Title of Invention

A CRYSTALLINE INORGANIC MATERIAL HAVING LONG-RANGE CRYSTALLINITY AND A METHOD OF MAKING A MENOSTRUCTURED INORGANIC MATERIAL

Abstract One aspect of the present invention relates to crystalline inorganic materials having long-range crystallinity and comprising a plurality of mesopores. A cross-sectional area of each of the plurality of mesopores is substantially the same. A method of producing a hydrocarbon material product is also disclosed. The method comprises contacting a higher molecular weight hydrocarbon material with the crystalline inorganic material under conditions of controlled temperature and pressure to produce a hydrocarbon material product having a lower molecular weight. A method of processing a polymer is also disclosed. The method comprises contacting a polymer with the crystalline inorganic material and thermally treating the polymer in the presence of the crystalline inorganic material. A method of water treatment is further disclosed. The method comprises contacting contaminated water with the crystalline inorganic material and removing contaminants from the water with the crystalline inorganic material.
Full Text Related Applications
This application claims the benefit of and priority to U.S. patent application serial
number 10/830,714, filed on April 23, 2004, and entitled "Mesostructured Zeolitic Materials,
and Methods of Making and Using the Same."
Government Funding
This invention was made with support under Grant Number DAAD19-02-D0002,
awarded by the Army Research Office; the government, therefore, has certain rights in the
invention.
Field of the Invention
The invention relates to crystalline inorganic materials having long-range crystallinity
and comprising a plurality of mesopores and to methods of producing a hydrocarbon material
product, processing a polymer and a method of water treatment.
Background of the Invention
Zeolites and related crystalline molecular sieves are widely used due to their regular
microporous structure, strong acidity, and ion-exchange capability, van Bekkum, H.,
Flanigen, E. M., Jacobs, P. A., Jansen, 1. C. (editors), Introduction to Zeolite Science and
Practice, 2nd edition. Studies in Surface Science and Catalysis, Vol. 137 (2001); Corma, A.,
Chem. Rev., 1997, 97, 2373-2419; Davis, M. E., Nature, 2002, 417,813-821. However, their
applications are limited by their small pore openings, which are typically narrower than 1
nm. The discovery ofMCM-41, with tuneable mesopores of2-10 nra, overcomes some of the
limitations associated with zeolites. Corma, A., Chem. Rev., 1997, 97,2373-2419; Kresge, C.
T., et al., Nature, 1992,259, 710-712; Kosslick, H., et al., Appl. Catal. A: Gen., 1999,184,
49-60; Linssen, T., Cassiers, K., Cool, P., Vansant, E. F., Adv. Coll. Interf. Sci., 2003,103,
121-147. However, unlike zeolites, MCM-41-type materials are not crystalline, and do not
possess strong acidity, high hydrothermal stability and high ion-exchange capability, which
are important for certain catalytic applications. Corma, A., Chem. Rev., 1997,97,2373-2419.
Over the past 10 years, a great deal of effort has been devoted to understanding and
improving the structural characteristics ofMCM-41. It was found that the properties of Al-
MCM-41 could be improved through (i) surface silylation, (ii) Al grafting on the pore walls
to increase acidity, (iii) salt addition during synthesis to facilitate the condensation of
aluminosilicate groups, (iv) use of organics typically employed in zeolite synthesis to
transform partially the MCM-41 wall to zeolite-like structures, (v) preparation of
zeolite/MCM~41 composites, (vi) substitution of cationic surfactants by tri-block copolymers
and Gemini amine surfactants to thicken the walls, and (vii) assembly of zeolite nanocrystals
into an ordered mesoporous structure. Liu, Y., Pinnavaia, T. 1., J Mater. Chem., 2002, 12,
3179-3190. In the latter approach, Liu et al. were able to prepare the first steam-stable
hexagonal aluminosilicate (named MSU-S) using zeolite Y nanoclusters as building blocks.
Pentasil zeolite nanoclusters were also used to produce MSU-S(mfi) and MSU-S(bea)).
United States Patent No. 5,849,258 to Lujano et al. aggregates the nuclei of
crystalline microporous molecular sieve material (e.g., the nuclei of zeolites) to provide a
narrowed size distribution of mesopore-sized pore volumes, forming a polycrystalline
material. Figure 1A is a schematic illustration of a prior art amorphous mesoporous material
100, which is described by, for example, Lujano and Pinnavaia. United States Patent No.
5,849,258 to Lujano et al. and Liu, Y., Pinnavaia, T. J., J Mater. Chem., 2002, 12,31793190.
As shown in Figure 1A, zeolite nucleii 105a, 105b, 105e were aggregated around surfactant
micelles under controlled conditions to form a solid. Thereafter, the aggregated nuclei 105a,
105b, 105c are washed in water and dried and the surfactant is extracted to provide a desired
mesopore-sized pore volume 110, forming amorphous mesoporous zeolite nuclei material
100. Each of the zeolite nuclei, for example, 105a, 105b, 105c, is a nanosized crystal. When
they are aggregated the material 100 is polycrystalline because the nuclei material is lacking
the long-range regular lattice structure of the crystalline state (i.e., the aggregated nuclei are
not fully crystalline or truly crystalline).
Some strategies have managed to improve appreciably the acidic properties of Al-
MCM-41 materials. Liu, Y., Pinnavaia, T. J., J. Mater. Chem., 2002,12,3179-3190; van
Donk, S., et al., Catal. Rev., 2003, 45, 297-319; KlOetstra, K. R., et al., Chem. Commun.,
1997, 23, 2281-2282; Corma, A., Nature, 1998, 396, 353-356; Karlsson, A., et al.,
Microporous Mesoporous Mater., 1999, 27, 181-192; Jacobsen, C. 1. H., et al., J. Am. Chem.
Soc, 2000,122, 7116-7117; Huang L., et al., J. Phys. Chem. B., 2000, 104, 2817-2823; On,
D. T., et al., Angew. Chem. Int. Ed, 2001, 17, 3248-3251; Liu, Y., et al., Angew. Chem. Int.
Ed, 2001, 7, 1255-1258. However, due to the lack of long-range crystallinity in these
materials, their acidity was not as strong as those exhibited by zeolites. Corma, A., Chem.
Rev., 1997, 97, 2373-2419. For example, semicrystalline mesoporous materials, such as
nanocrystalline aluminosilicate PNAs and A1-MSU-S(mFI), even being more active than
conventional Al-MCM-41, showed significantly lower activity than H-ZSM-5 for cumene
cracking; the catalyst activity for this reaction has usually been correlated to the Bronsted
acid strength of the catalyst. Corma, A., Chem. Rev., 1997, 97, 2373-2419; Liu, Y.,
Pinnavaia, T. J., J. Mater. Chem., 2002, 12, 3179-3190; Kloetstra, K. R., et al., Chem.
Commun., 1997, 23, 2281-2282; Jacobsen, C. J. H., et al, J. Am. Chem. Soc, 2000, 122,
7116-7117.
Previous attempts to prepare mesostructured zeolitic materials have been ineffective,
resulting in separate zeolitic and amorphous mesoporous phases. Karlsson, A., et al.,
Microporous Mesoporous Mater., 1999, 27, 181-192; Huang L., et al., J. Phys. Chem. B.,
2000, 104, 2817-2823.
Moreover, some authors pointed out the difficulty of synthesizing thin-walled
mesoporous materials, such as MCM-41, with zeolitic structure, due to the surface tension
associated with the high curvature of the mesostructure. Liu, Y., Pinnavaia, T. J., J. Mater.
Chem., 2002, 12, 3179-3190. Thus, the need exists for zeolite single crystals with ordered
mesoporosity, and methods of making and using them.
Summary of the Invention
In one aspect, the present invention relates to a crystalline inorganic material
organized in a mesostructure. In a further embodiment, the inorganic material is a metal
oxide. In a further embodiment, the inorganic material is a zeolite. In a further embodiment,
the inorganic material is a zeotype. In a further embodiment, the inorganic material has a
faujasite, mordenite, or ZSM-5 (MFI) structure. In a further embodiment, the mesostructure
has the hexagonal pore arrangement ofMCM-41. In a further embodiment, the mesostructure
has the cubic pore arrangement ofMCM-48. In a further embodiment, the mesostructure has
the lamellar pore arrangement ofMCM-50. In a further embodiment, the mesostructure has
pores organized in a foam arrangement. In a further embodiment, the mesostructure has
randomly placed pores.
In a further embodiment, the mesostructure is a one dimensional nanostructure. In a
further embodiment, the nanostructure is a nanotube, nanorod, or nanowire.
In a further embodiment, the mesostructure is a two dimensional nanostructure. In a
further embodiment, the nanostructure is a nanoslab, nanolayer, or nanodisc.
n a further embodiment, the crystalline inorganic material is Y[MCM-41],
MOR[MCM-41], orZSM-5[MCM-41].
In a further embodiment, the mean pore diameter within the mesostructure is about 2
to about 5 nm. In a further embodiment, the mean pore diameter within the mesostructure is
about 2 to about 3 nm. In a further embodiment, the wall thickness within the mesostructure
is about 1 to about 5 nm. In a further embodiment, the wall thickness within the
mesostructure is about 1 to about 3 nm.
In another aspect, the present invention relates to a method of preparing a
mesostructured zeolite comprising: a) adding a zeolite to a medium comprising an acid or
base, and optionally a surfactant; b) adding a surfactant to the medium from step a) if it is not
there already; c) optionally adding a swelling agent to the medium from step b); d) optionally
hydrothermally treating the medium from step b) or c); and e) washing and drying the
resulting material.
In a further embodiment, the resulting material is further calcined at elevated
temperatures. In a further embodiment, the calcination step is performed in air or oxygen. In
a further embodiment, the calcination step is performed in an inert gas. In a further
embodiment, the inert gas is N2. In a further embodiment, the maximum elevated
temperatures are at about 500 to 600°C. In a further embodiment, the maximum elevated
temperatures are at about 550°C.
In a further embodiment, the zeolite is selected from the group consisting of faujasite
(FAU), mordenite (MOR), and ZSM-5 (MFI). In a further embodiment, the medium in step
a) comprises a base. In a further embodiment, the base is an alkali hydroxide, alkaline earth
hydroxide, NH4OH or a tetralkylammonium hydroxide. In a further embodiment, the base is
NaOH, NH4OH, or tetramethylammonium hydroxide. In a further embodiment, the medium
in step a) comprises an acid. In a further embodiment, the acid is HF. In a further
embodiment, the surfactant is an alkylammonium halide. In a further embodiment, the
surfactant is a cetyltrimethylammonium bromide (CTAB) surfactant. In a further
embodiment, hydrothermally treating the medium from step b) or c) occurs at about 100 to
about 200°C. In a further embodiment, hydrothermally treating the medium from step b) or
c) occurs at about 120 to about 180°C. In a further embodiment, hydrothermally treating the
medium from step b) or c) occurs at about 140 to about 160°C. In a further embodiment,
hydrothermally treating the medium from step b) or c) occurs at about 150°C. In a further
embodiment, hydrothermally treating the medium from step b) or c) takes place overnight. In
a further embodiment, hydrothermally treating the medium from step b) or c) takes place
over about 20 hours.
In another aspect, the present invention relates to a mesostructured zeolite prepared
by any of the aforementioned methods.
In another aspect, the present invention relates to a method of preparing a
mesostructured zeolite comprising: a) adding a zeolite in its acidic form to a medium
comprising a base, and optionally a surfactant, in which the zeolite is partially dissolved to
produce a suspension; b) adding a surfactant to the medium from step a) if it is not there
already; c) optionally adding a swelling agent to the medium from step b); d) optionally
hydrothermally treating the medium from step b) or c); e) washing and drying the resulting
material; and f) removing the surfactant from the resulting material either by calcining at
elevated temperatures, or by solvent extraction.
In another aspect, the present invention relates to a mesostructured zeolite prepared
by the above method, wherein the mesostructured zeolite is in the form of a nanotube,
nanorod, or nanowire.
In another aspect, the present invention relates to a mesostructured zeolite prepared
by the above method, wherein the mesostructured zeolite is in the form of a nanoslab,
nanolayer, or nanodisc.
In another aspect, the present invention relates to a method of anchoring a positively
charged chemical species to a mesostructured zeolite comprising contacting the
mesostructured zeolite and the positively charged species in a medium. In a further
embodiment, the positively charged species is selected from the group consisting of cations
of an element, quaternary amines, ammonium ions, pyridinium ions, phosphonium ions, and
mixtures thereof.
In another aspect, the present invention relates to a method of anchoring a chemical
species to a mesostructured zeolite comprising: contacting the mesostructured zeolite in its
acidic form and a basic chemical species in a medium. In a further embodiment, the basic
chemical species is an inorganic base or an organic base. In a further embodiment, the basic
chemical species is selected from the group consisting of hydroxide, amine, pyridine,
phosphine, and mixtures thereof.
In another aspect, the present invention relates to a method of anchoring a
homogeneous catalyst on a mesostructured zeolite comprising: contacting a mesostructured
zeolite comprising a chemical species anchored on it, and a homogeneous catalyst in a
medium, wherein the anchored chemical species is capable of acting as a ligand to the
homogeneous catalyst.
In another aspect, the present invention relates to a method of supporting a
heterogeneous catalyst on a mesostructured zeolite comprising contacting the mesostructured
zeolite and the heterogeneous catalyst by a method selected from the group consisting of
physical mixture, dry impregnation, wet impregnation, incipient wet impregnation, ion-
exchange, and vaporization. In a further embodiment, the heterogeneous catalyst comprises a
metal or a mixture thereof. In a further embodiment, the heterogeneous catalyst comprises a
metal oxide or a mixture thereof. In a further embodiment, the heterogenous catalyst
comprises a nanoparticle, cluster, or colloid.
In another aspect, the present invention relates to a method of catalytically cracking
an organic compound comprising contacting the organic compound with a mesostructured
zeolite. In a further embodiment, the organic compound is a hydrocarbon. In a further
embodiment, the organic compound is an unsaturated hydrocarbon. In a further embodiment,
the organic compound is an aromatic hydrocarbon. In a further embodiment, the organic
compound is an alkylated benzene. In a further embodiment, the organic compound is 1,3,5-
triisopropyl benzene. In a further embodiment, the organic compound is crude oil. In a
further embodiment, the organic compound is gas-oil. In a further embodiment, the organic
compound is vacuum gas oil. In a further embodiment, the mesostructured zeolite has the
zeolitic structure of a faujasite (FAU), mordenite (MOR), or ZSM-5 (MFI). In a further
embodiment, the mesostructured zeolite has the hexagonal pore arrangement of MCM-41. In
a further embodiment, the mesostructured zeolite is Y[MCM-41], MOR[MCM-41], or ZSM-
5[MCM-41].
In another aspect, the present invention relates to a method of refining crude oil
comprising contacting the crude oil with a mesostructured zeolite. In a further embodiment,
the contacting of the oil with the mesostructured zeolite takes place within a Fluid Catalytic
Cracking Unit. In a further embodiment, production of gasoline is increased relative to the
amount of gasoline produced in the absence of the mesostructured zeolite. In a further
embodiment, production of light olefins is increased relative to the amount of light olefins
produced in the absence of the mesostructured zeolite.
In another aspect, the present invention relates to a method of catalytically degrading
a polymer comprising contacting the polymer with a mesostructured zeolite. In a further
embodiment, the polymer is a hydrocarbon polymer. In a further embodiment, the polymer is
a poly(alkylene), poly(alkynyl) or poly(styrene). In a further embodiment, the polymer is
polyethylene (PE). In a further embodiment, the mesostructured zeolite has the zeolitic
structure of a faujasite (FAU), mordenite (MOR), or ZSM-5 (MFI). In a further embodiment,
the mesostructured zeolite has the hexagonal pore arrangement ofMCM-41. In a further
embodiment, the mesopostructured zeolite is Y[MCM-41], MOR[MCM-41], or ZSM-
5[MCM-41].
In another aspect, the invention relates to an inorganic material having a fully
crystalline mesostructure. The fully crystalline mesostructure includes mesopore surfaces
defining a plurality of mesopores. A cross-sectional area of each of the plurality of
mesopores is substantially the same. In one embodiment, the material has a pore volume. For
example, the plurality of mesopores have a pore volume of the material and the pore volume
of the plurality of mesopores is controlled. The pore volume can be from about 0.05 cc/g to
about 2 cc/g, in another embodiment, the pore volume is from about 0.5 cc/g to about 1 cc/g.
The fully crystalline inorganic material can be, for example, mono crystalline, multi
crystalline, or single crystalline.
An area of each of the plurality of mesopores has a controlled cross sectional area
range. The controlled cross sectional area has, for example, a controlled distribution range.
Optionally, the controlled cross sectional area has a diameter and the diameter ranges from
about 2 ran to about 60 nm. In one embodiment, each mesopore diameter has a controlled
distribution range, for example, each mesopore diameter falls within a 1 nm distribution
range. Alternatively, the controlled cross sectional area has a diameter ranging from about 2
nm to about 5 nm, or from about 2 nm to about 3 nm.
The inorganic material can have, for example, a 1D pore structure, a 2D pore
structure, or a 3D pore structure prior to defining the plurality of mesopores. The material
can be a metal oxide, a zeolite, a zeotype, aluminophosphate, gallophosphate,
zincophosphate, titanophosphate, faujasite (FAU), mordenite (MOR), ZSM-5 (MFI), or
CHA, or any combination thereof.
The fully crystalline mesostructure can have a controlled pore arrangement. The
mesostructure pore arrangement can be: an organized pore arrangement, the hexagonal pore
arrangement of MCM-41, the cubic pore arrangement of MCM-48, the lamellar pore
arrangement of MCM-50, the hexagonal pore arrangement ofSBA-15, or a foam-like
arrangement. Alternatively, the mesostructure can have randomly placed pores. The fully
crystalline mesostructure can be, for example, Y[MCM-41], MOR[MCM-41], ZSM-
5[MCM-41], Y[MCM-48], MOR[MCM-48], ZSM-5[MCM-48], Y[MCM-50], MOR[MCM-
50], or ZSM-5 [MCM-50]. A wall thickness between adjacent mesopores can measure about
1 nm to about 5 nm, or about 1 nm to about 3 nm.
A charged chemical species, for example a positively charged chemical species, can
be anchored to the fully crystalline mesostructure. The charged chemical species can be
cations of an element, quaternary amines, ammonium ions, pyridinium ions, or phosphonium
ions, or any combination thereof. Alternatively, a chemical species can be anchored and/or
covalently bonded to the fully crystalline mesostructure. The chemical species can be a basic
chemical species, an inorganic base, an organic base, hydroxide, amine, pyridine, or
phosphine, or any combination thereof. In another embodiment, a homogeneous catalyst
adheres to the inorganic material and a chemical species binds to the homogeneous catalyst A
heterogeneous catalyst can be supported by the fully crystalline mesostructure. The
heterogeneous catalyst can be a metal, a metal oxide, a nanoparticle, a cluster, or a colloid, or
any combination thereof.
In another aspect, the invention relates to an inorganic material that has an external
surface contour substantially the same as the external surface contour of the material prior to
defining the plurality of mesopores. In another aspect, the invention relates to a material that
has a chemical composition framework substantially the same as the chemical composition
framework of the material prior to defining the plurality of mesopores. For example, the
framework has unchanged stoichiometry after the mesopores are defined.
In another aspect, the invention relates to a material that has a connectivity
substantially the same as the connectivity of the material prior to defining the plurality of
mesopores. In another aspect, the invention relates to a material that has an improved
intracrystalline diffusion compared to the intracrystalline diffusion of the material prior to
defining the plurality of mesopores.
In another aspect, the invention relates to a method of making an inorganic material
that includes the steps of (a) providing a fully crystalline inorganic material, (b) exposing the
fully crystalline inorganic material to a pH controlled medium under a first set of time and
temperature conditions, (c) exposing the fully crystalline inorganic material to a surfactant
under a second set of time and temperature conditions, and (d) treating the inorganic material
by controlling the first and second set of time and temperature conditions to form a plurality
of mesopores having a controlled cross sectional area within the fully crystalline inorganic
material. Optionally, the method includes the step (e) adjusting the first and second set of
time and temperature conditions such that the plurality of mesopores is arranged in a
hexagonal [MCM-41] pore arrangement, in a cubic [MCM-48] pore arrangement, in a
lamellar [MCM-50] pore arrangement, in a hexagonal [SBA-15] pore arrangement, in a
foam-like pore arrangement, in a random pore arrangement, in an organized pore
arrangement, or in a controlled pore arrangement in the fully crystalline inorganic material.
In one embodiment, the step (b) includes selecting the pH controlled medium to
control a pore volume of the fully crystalline inorganic material, to control a diameter of each
of the plurality of mesopores, or to control a cross sectional area of each of a plurality of
mesopores in the fully crystalline inorganic material. In another embodiment, the step (c)
includes selecting a quantity of the surfactant to control a pore volume of the fully crystalline
inorganic material, to control a diameter of each of the plurality of mesopores, or to control a
cross sectional area of each of a plurality of mesopores in the fully crystalline inorganic
material. In another embodiment, the method further includes the step of adding a swelling
agent and/or a triblock copolymer to the pH controlled medium.
In another embodiment, the material produced in step (d) is washed and dried.
Alternatively, or in addition, surfactant is removed from material produced in step (d) by, for
example, extracting the surfactant and/or calcining the surfactant after performing steps (a)
through (d).
In another embodiment, the first or second temperature conditions can include
hydrothermal conditions. The first or second temperature conditions can include room
temperature conditions and/or can range from about 100 to about 200°C. The first or second
time conditions can range from about 1 hour to about 2 weeks.
The fully crystalline inorganic material can be a metal oxide, a zeolite, a zeotype,
aluminophosphate, gallophosphate, zincophosphate, titanophosphate, faujasite (FAU),
mordenite (MOR), ZSM-5 (MFI), or CRA, or any combination thereof. The pH controlled
medium can include a pH control setpoint that is at least about 8 to not more than about 12, at
least about 10 to not more than about 14, at least about 2 to not more than about 6, or at least
about -2 to not more than about 2.
The surfactant can be cationic, ionic, or neutral surfactants, or any combination
thereof. For example, the surfactant can be cetyltrimethylammonium bromide (CTAB).
The method of making the inorganic material can also include introducing a charged
chemical species to the fully crystalline inorganic material produced in step (d). The charged
chemical species can: positively charged. In addition, the charged chemical species can be
cations of an element, quaternary amines, ammonium ions, pyridinium ions, or phosphonium
ions, or any combinations thereof.
The method of making the inorganic material can also include introducing a chemical
species to the fully crystalline inorganic material produced in step (d). The chemical species
can be a basic chemical species, an inorganic base, an organic base, hydroxide, amine,
pyridine, or phosphine, or any combination thereof. A homogeneous catalyst can be added
such that the chemical species binds to the homogeneous catalyst. A heterogeneous catalyst
can be contacted with the fully crystalline inorganic material produced in step (d). The
heterogeneous catalyst can be a metal, a metal oxide, a nanoparticle, a cluster, or a colloid, or
any combination thereof.
In another aspect, the invention relates to an inorganic material made by the process
of (a) providing a fully crystalline inorganic material, (b) exposing the fully crystalline
inorganic material to a pH controlled medium under a first set of time and temperature
conditions, (c) exposing the fully crystalline inorganic material to a surfactant under a second
set of time and temperature conditions; and (d) treating the inorganic material by controlling
the first and second set of time and temperature conditions to form a plurality of mesopores
having a controlled cross sectional area within the fully crystalline inorganic material.
In another aspect, the invention relates to a hydrocarbon material produced by the
process of reacting a larger hydrocarbon material in the presence of a catalyst including
inorganic material having a fully crystalline mesostructure. The fully crystalline
mesostructure includes mesopore surfaces defining a plurality ofmesopores. A cross-
sectional area of each ofthe plurality ofmesopores is substantially the same. The hydrocarbon
material produced by this process can be 1,3-diisopropyl benzene, gasoline, propylene,
butene, coke, total dry gas, or liquefied petroleum gases, or combinations thereof.
In another aspect, the invention relates to a method of catalytically cracking an
organic compound. The method includes the step of contacting the organic compound with
an inorganic material having a fully crystalline mesostructure. The fully crystalline
mesostructure includes mesopore surfaces defining a plurality of mesopores. A cross-
sectional area of each of the plurality of mesopores is substantially the same. The organic
compound can be at least one of a hydrocarbon, unsaturated hydrocarbon, an aromatic
hydrocarbon, an alkylated benzene, 1,3,5-triisopropyl benzene, crude oil, gas-oil, or vacuum
gas oil. Optionally, the cross sectional area has a diameter greater than a diameter of the
organic compound being cracked.
In another aspect, the invention relates to a method of processing crude oil. The
method includes contacting crude oil with an inorganic material having a fully crystalline
mesostructure. The fully crystalline mesostructure includes mesopore surfaces defining a
plurality of mesopores. A cross-sectional area of each of the plurality of mesopores is
substantially the same. The crude oil is reacted in the presence of the inorganic material
under conditions of controlled temperature and pressure. The crude oil can be reacted in the
presence of the inorganic material within a Fluid Catalytic Cracking unit. In one
embodiment, the fraction of gasoline produced is increased relative to the amount of gasoline
produced using a fully crystalline inorganic material. In another embodiment, light olefin
production is increased relative to the amount of light olefins produced using a fully
crystalline inorganic material.
In another aspect, the invention relates to a method of processing a polymer. The
method includes contacting a polymer with an inorganic material having a fully crystalline
mesostructure. The fully crystalline mesostructure includes mesopore surfaces defining a
plurality of mesopores. A cross-sectional area of each of the plurality of mesopores is
substantially the same. The polymer can be thermally treated in the presence of the inorganic
material. The polymer can be a hydrocarbon polymer, poly(alkylene), poly(alkynyl),
poly(styrene), or polyethylene (PE), or any combination thereof.
In another aspect, the invention relates to a benzene compound made by the process
of contacting a crude oil with an inorganic material having a fully crystalline mesostructure.
The fully crystalline mesostructure includes mesopore surfaces defining a plurality of
mesopores. A cross-sectional area of each of the plurality of mesopores is substantially the
same. The crude oil is reacted in the presence of the inorganic material under conditions of
controlled temperature and pressure. The benzene compound can include benzene derivatives
such as, for example, toluene and xylene. In one embodiment the quantity of benzene
compound produced with the inorganic material having a fully crystalline mesostructure is a
lesser quantity than is produced with a conventional unmodified fully crystalline zeolite.
In another aspect, the invention relates to a gasoline compound made by the process
of contacting a crude oil with an inorganic material having a fully crystalline mesostructure.
The fully crystalline mesostructure includes mesopore surfaces defining a plurality of
mesopores. A cross-sectional area of each of the plurality of mesopores is substantially the
same. The crude oil is reacted in the presence of the inorganic material under conditions of
controlled temperature and pressure. In one embodiment the quantity of gasoline produced
with the inorganic material having a fully crystalline mesostructure is a greater quantity than
is produced with a conventional unmodified fully crystalline zeolite.
In another aspect, the invention relates to a method of water treatment that includes
contacting contaminated water with an inorganic material having a fully crystalline
mesostructure. The fully crystalline mesostructure includes mesopore surfaces defining a
plurality of mesopores. A cross-sectional area of each of the plurality of mesopores is
substantially the same. Contaminants from the water are removed with the inorganic
material. In one embodiment, the removed contaminant is a dye.
In another aspect, the invention relates to an inorganic material that includes a
crystalline nanostructure having a plurality of members. Each member defines a plurality of
pores and adjacent members define voids therebetween. At least one dimension of each of
the plurality of members is less than 100 nm. In one embodiment, at least one dimension of
each of the plurality of member measures between about 3 nm and about 20 nm. In one
embedment, the inorganic material is semi crystalline or poly crystalline. The nanostructure
can be one dimensional, two dimensional, or three dimensional. The nanostructure can be a
nanotube, nanoring, nanorod, nanowire, nanoslab, nanolayer, or nanodisc. In one
embodiment, one member has one nanostructure and another member has another
nanostructure, for example, a nanorod is adjacent a nanotube. The inorganic material can
include a metal oxide, a zeolite, a zeotype, aluminophosphate, gallophosphate,
zincophosphate, titanophosphate, faujasite (FAD), mordenite (MOR), and ZSM-5 (MFI), or
CHA, or any combination thereof. The nanostructure can be, for example, nanostructure is
Y[ZNR], MORfZNR], or ZSM-5[ZNR].
In another aspect, the invention relates to a method of making an inorganic material
that includes the steps of (a) providing a crystalline inorganic material, (b) exposing the
crystalline inorganic material to a pH controlled medium to partially dissolve the crystalline
inorganic material producing an amorphous inorganic material, (c) adjusting the pH of the
amorphous inorganic material, (d) exposing the amorphous inorganic material to a surfactant,
and(e) treating the inorganic material by controlling time and temperature conditions of steps
(b) through (d) to form nanostructures. Optionally, the method further includes treating the
inorganic material by controlling the time and temperature conditions to first form a [MCM-
50] mesostructure and then to form nanostructures.
In one embodiment of the method, the pH controlled medium has a pH control
setpoint that is at least about 10 to not more than about 14, that is at least about 2 to not more
than about 6, or that is at least about -2 to not more than about 2. In another embodiment, the
amorphous inorganic material has a pH ranging from about 8 to about 12. The temperature
conditions can range from about 100 to about 200°C. The time can range from 15 about 12
hours to about 2 weeks. The temperature conditions can be hydrothermal temperature
conditions.
In one embodiment, the surfactant employed in accordance with the method is a
cationic surfactant, an ionic surfactant, or a neutral surfactants, or any combination thereof.
For example, cetyltrimethylammonium bromide (CTAB) can be employed as a surfactant.
The fully crystalline inorganic material can be a metal oxide, a zeolite, a zeotype,
aluminophosphate, gallophosphate, zincophosphate, titanophosphate, faujasite (FAU),
mordenite (MOR), and ZSM-5 (MFI), or CHA, or any combination thereof.
In another aspect, the invention relates to an inorganic material made by the process
of (a) providing a crystalline inorganic material, (b) exposing the crystalline inorganic
material to a pH controlled medium to partially dissolve the crystalline inorganic material
producing an amorphous inorganic material, (c) adjusting the pH of the amorphous inorganic
material, (d) exposing the amorphous inorganic material to a surfactant, and(e) treating the
inorganic material by controlling time and temperature conditions of steps (b) through (d) to
form nanostructures.
In another aspect, the invention relates to a cracked organic compound made by the
process of contacting an organic compound with an inorganic material that includes a
crystalline nanostructure having a plurality of members. Each member defines a plurality of
pores and adjacent members define voids therebetween. At least one dimension of each of
the plurality of members is less than 100 nm. In one embodiment, the hydrocarbon material
is 1,3-diisopropyl benzene, gasoline, propylene, butene, coke, total dry gas, or liquefied
petroleum gases, or combinations thereof
In another aspect, the invention relates to a method of catalytically cracking an
organic compound. The method includes contacting the organic compound with an inorganic
material that includes a crystalline nanostructure having a plurality of members. Each
member defines a plurality of pores and adjacent members define voids therebetween. At
least one dimension of each of the plurality of members is less than 100 nm. In one
embodiment, the organic compound is at least one of a hydrocarbon, unsaturated
hydrocarbon, an aromatic hydrocarbon, an alkylated benzene, 1,3,5-triisopropyl benzene,
crude oil, gas-oil, or vacuum gas oil.
In another aspect, the invention relates to a method of processing crude oil. The
method includes contacting crude oil with an inorganic material that includes a crystalline
nanostructure having a plurality of members. Each member defines a plurality of pores and
adjacent members define voids therebetween. At least one dimension of each of the plurality
of members is less than 100 nm. The crude oil is reacted in the presence of the inorganic
material under conditions of controlled temperature and pressure. Optionally, the crude oil is
reacted in the presence of the inorganic material within a Fluid Catalytic Cracking unit. In
one embodiment, the fraction of gasoline produced is increased relative to the amount of
gasoline produced using a fully crystalline inorganic material. In another embodiment, light
olefin production is increased relative to the amount of light olefins produced using a fully
crystalline inorganic material.
In another aspect, the invention relates to a method of processing a polymer. The
method includes contacting a polymer with an inorganic material that includes a crystalline
nanostructure having a plurality of members. Each member defines a plurality of pores and
adjacent members define voids therebetween. At least one dimension of each of the plurality
of members is less than 100 nm. The polymer can be thermally treated in the presence of the
inorganic material. The polymer can be a hydrocarbon polymer, poly(alkylene),
poly(alkynyl), poly(styrene), or polyethylene (PE), or any combination thereof.
In another aspect, the invention relates to a benzene compound made by the process
of contacting a crude oil with an inorganic material that includes a crystalline nanostructure
having a plurality of members. Each member defines a plurality of pores and adjacent
members define voids therebetween. At least one dimension of each of the plurality of
members is less than 100 nm. The crude oil is reacted in the presence of the inorganic
material under conditions of controlled temperature and pressure. The benzene compound
can include benzene derivatives such as, for example, toluene and xylene. In one
embodiment the quantity of benzene compound produced with the crystalline nanostructure
material is a lesser quantity than is produced with a conventional unmodified fully crystalline
zeolite.
In another aspect, the invention relates to a gasoline compound made by the process
of contacting a crude oil with an inorganic material that includes a crystalline nanostructure
having a plurality of members. Each member defines a plurality of pores and adjacent
members define voids therebetween. At least one dimension of each of the plurality of
members is less than 100 nm. The crude oil is reacted in the presence of the inorganic
material under conditions of controlled temperature and pressure. In one embodiment the
quantity of gasoline produced with the inorganic material having a crystalline nanostructure
is a greater quantity than is produced with a conventional unmodified fully crystalline zeolite.
In another aspect, the invention relates to a method of water treatment that includes
contacting contaminated water with an inorganic material that includes a crystalline
nanostructure having a plurality of members. Each member defines a plurality of pores and
adjacent members define voids therebetween. At least one dimension of each of the plurality
of members is less than 100 nm. Contaminants from the water are removed with the
inorganic material. In one embodiment, the removed contaminant is a dye.
These embodiments of the present invention, other embodiments, and their features
and characteristics, will be apparent from the description, drawings and claims that follow.
Brief Description of the Accompanying Drawings
Figure 1A is a schematic diagram of a prior art polycrystalline mesoporous material.
Figure 1B is a schematic illustration of a fully crystalline mesostructured zeolite of
the present invention.
Figure 1C depicts a TEM image of a nanosostructured zeolite of the present
invention where the nanostructure shape includes nanorods.
Figure 1D depicts the X-ray diffraction pattern of the fully crystalline mesostructured
zeolite H-Y[MCM-41]. Both the ordered mesostructure MCM-41 (revealed by the XRD
peaks at low angles) and the unmodified zeolitic fully crystalline structure H-Y are present.
Figure 2 depicts the X-ray diffraction pattern of the fully crystalline mesostructured
zeolite H-MOR[MCM-41]. Both the ordered mesostructure MCM-41 (revealed by the
XRD peaks at low angles) and the unmodified zeolitic fully crystalline structure H-MOR are
present.
Figure 3 depicts the X-ray diffraction pattern of the fully crystalline mesostructured
zeolite H-ZSM-5[MCM-41]. Both the ordered mesostructure MCM-41 (revealed by the XRD
peaks at low angles) and the unmodified zeolitic crystalline structure H-ZSM-5 are present.
Figure 4 depicts FTIR characterization peaks for the fully crystalline mesostructured
zeolite H-Y[MCM-41], labeled Meso-H-Y, and the unmodified zeolite Y.
Figure 5 depicts FTIR spectra of the fully crystalline mesostructured zeolites H-
Y[MCM-41] (upper top), H-MOR[MCM-41] (upper middle), H-ZSM-5 [MCM-41] (upper
bottom) and FTIR spectra of their unmodified fully crystalline zeolitic versions H-Y (lower
top), H-MOR (lower middle), H-ZSM-5 (lower bottom). A match between each fully
crystalline mesostructured zeolite and its corresponding unmodified zeolite is observed,
indicating the fully zeolitic connectivity present in the fully crystalline mesostructured
zeolites.
Figure 6 depicts the physisorption isotherm of N2 at 77 K of the fully crystalline
mesostructured zeolite H-Y[MCM-41], labeled Meso-H-Y, and its unmodified zeolitic
version, H-Y. The pore size distribution (BJH method) of the fully crystalline mesostructured
zeolite is included in inset. The presence of well developed narrow pore size mesoporosity in
the mesostructured sample is evident by the sharp uptake at P/P0~0.3.
Figure 7 depticts the physisorption isotherm of N2 at 77 K of the fully crystalline
mesostructured zeolite H-MOR[MCM-41], labeled Meso-H-MOR, and its unmodified
zeolitic version, H-MOR. The pore size distribution (BJH method) of the fully crystalline
mesostructured zeolite is included in inset. The presence of well developed narrow pore size
mesoporosity in the mesostructured sample is evident by the sharp uptake at P/P0~0.3.
Figure 8 depicts the physisorption isotherm of N2 at 77 K of the fully crystalline
mesostructured H-ZSM-5[MCM-41], labeled Meso-H-ZSM-5, and its unmodified zeolitic
version, H-ZSM-5. The pore size distribution (Bill method) of the fully crystalline
mesostructured zeolite is included in inset. The presence of well developed narrow pore size
mesoporosity in the mesostructured sample is evident by the sharp uptake at P/P0~0.3.
Figure 9 depicts pore volumes (darker columns) of fully crystalline mesostructured
zeolites H-Y[MCM-41] (left), H-MOR[MCM-41] (center), and H-ZSM-5[MCM-41] (right)
and their unmodified zeolitic versions (lighter columns) of H-Y (left), H-MOR (center), and
H-ZSM-5 (right).
Figure 10 depicts images obtained by transmission electron microscopy (TEM) of a)
detail of a H-Y[MCM-41] fully crystalline mesostructured zeolite, and b) detail of a H-
Y[MCM-41] fully crystalline mesostructured zeolite at different focus. The electron
diffraction patterns are included as insets.
Figure 11 depict a TEM image of a fully crystalline mesostructured zeolite of the
present invention.
Figure 12 depicts a TEM image of a fully crystalline mesostructured zeolite of the
present invention.
Figure 13 depicts a schematic illustration of catalytic cracking of 1,3,5-triisopropyl
benzene by the unmodified conventional zeolite H-Y.
Figure 14 depicts a schematic illustration of catalytic cracking of 1,3,5-triisopropyl
benzene a fully crystalline mesostructured zeolite of the present invention.
Figure 15 depicts catalytic activity for 1,3,5-triisopropyl benzene cracking shown as
conversion vs. time for the fully crystalline mesostructured zeolite H-Y[MCM-41], labeled
Meso-HY, its unmodified zeolitic version H-Y, and a conventional Al-MCM-41. A 50
mL/min of He flow saturated with 1,3,5-triisopropylbenzene at 120°C was flowed at 200 °C
over 50 mg of catalyst.
Figure 16 depicts the catalytic cracking of 1,3,5-triisopropyl benzene with the fully
crystalline mesostructured zeolite H-Y[MCM-41], labeled Meso-H-Y, to diisopropyl benzene
and cumene. The H-Y[MCM-41] results are compared to the normalized results from a
commercial sample of unmodified fully crystalline zeolite H-Y. Catalytic cracking with the
fully crystalline mesostructured zeolite H-Y[MCM-41] results in higher selectivity and
reduction in benzene production.
Figure 17 depicts the hydrothermal stability of the fully crystalline mesostructured
zeolite H-Y, H-Y[MCM-41], labeled Meso-H-Y, compared to the conventional non-
mesolytic zeolite Al-MCM-41.
Figure 18 depicts catalytic activity for 1,3,5-triisopropyl benzene cracking shown as
conversion vs. time for the fully crystalline mesostructured zeolite H-MOR[MCM-48],
labeled Meso-HMOR, and its unmodified zeolitic version H-MOR. A 50 mL/min of He flow
saturated with 1,3,5-triisopropylbenzene at 120 °C was flowed at 200 CC over 50 mg of each
catalyst, H-MOR[MCM-48] and H-MOR.
Figure 19 depicts catalytic activity for 1,3,5-triisopropyl benzene cracking shown as
conversion vs. time for the fully crystalline mesostructured zeolite H-ZSM-5[MCM-41],
labeled Meso-H-ZSM-5, and its unmodified zeolitic version H-ZSM-5. A 50 mL/min of He
flow saturated with 1,3,5-triisopropylbenzene at 120 °C was flowed at 200 °C over 50 mg of
each catalyst, H-ZSM-5[MCM-41] and H-ZSM-5.
Figure 20A depicts, on the left hand side Y axis, the conversion of 1,3,5-
triisopropylbenzene versus time for the nanostructure H-MOR[ZNR] and the unmodified
fully crystalline zeolite H-MOR. The ratio of benzene produced by H-MOR/ benzene
produced by H-MOR[ZNR] as a function of time is also shown on the right hand side Y axis.
A helium flow of 50 mL/min saturated with 1,3,5-triisopropylbenzene at 120°C was
introduced over 50 mg of each catalyst, H-MOR[ZNR] and H-MOR, at 200°C.
Figure 20B depicts microactivity test (MAT) results of a conventional fully
crystalline zeolite H-Y (Si/Al=15) and its fully crystalline mesostructured version H-
Y[MCM-41].
Figure 20C depicts the composition of the LPG fraction obtained by Microactivity
test (MAT) of a conventional fully crystalline zeolite H-Y (Si/Al=15) and its fully crystalline
mesostructured version H-Y[MCM-41].
Figure 21 depicts the percentage of polyethylene (PE) weight lost vs. temperature for
the mixtures of catalysts in weight ratio to PE labelled: (A): no catalyst, (B): H-ZSM-5:PE
1:2, (C): H-ZSM-5[MCM-41]:PE 1:2, (D): H-ZSM-5:PE 1:1, (E) H-ZSM-5:PE 2:1, (F): H-
ZSM-
5[MCM-41]:PE 1:1, and (G) H-ZSM-5[MCM-41]:PE 2:1.
Figure 22 depicts the FTIR spectra of a) H-Y[MCM-41], b) NH4-Y[MCM-41], c)
NH2(CH2)2NMe3Cl, d) NH2(CH2)2NMe3-Y[MCM-41], d) Rh(PPh3)3Cl, and e)
Rh(PPh3)3NH2(CH2)2NMe3-Y[MCM-41 ].
Detailed Description of the Invention
Definitions
For convenience, before further description of the present invention, certain terms
employed in the specification, examples, and appended claims are collected here. These
definitions should be read in light of the remainder of the disclosure and understood as by a
person of skill in the art.
The articles "a" and "an" are used herein to refer to one or more than one (i.e., at least
one) of the grammatical object of the article. By way of example, "an element" means one
element or more than one element.
The term "catalyst" is art-recognized and refers to any substance that notably affects
the rate of a chemical reaction without itself being consumed or significantly altered.
The terms "comprise" and "comprising" are used in the inclusive, open sense,
meaning that additional elements may be included.
The term "cracking" is art-recognized and refers to any process of breaking up
organic compounds into smaller molecules.
The term "including" is used to mean "including but not limited to". "Including" and
"including but not limited to" are used interchangeably.
"MCM-41" represents a Mobil composite of matter and refers to an amorphous
mesoporous silica with a hexagonal pore arrangement, wherein the mean pore diameter is in
the range of about 2-10 nm.
"MCM-48" represents a Mobil composite of matter and refers to an amorphous
mesoporous silica with a cubic pore arrangement, wherein the mean pore diameter is in the
range of about 2-10 nm.
"MCM-50" represents a Mobil composite of matter and refers to an amorphous
mesoporous silica with a lamellar pore arrangement, wherein the mean pore diameter is in
the range of about 2-10 nm.
The term "mesoporous" is art-recognized and refers to a porous material comprising
pores with an intermediate size, ranging anywhere from about 2 to about 50 nanometers.
The term "mesostructure" is art-recognized and refers to a structure comprising
mesopores which control the architecture of the material at the mesoscopic or nanometer
scale, including ordered and non-ordered mesostructured materials, as well as nanostructured
materials, i.e. materials in which at least one of their dimension is in the nanometer size
range, such as nanotubes, nanorings, nanorods, nanowires, nanoslabs, and the like.
The term "mesostructured zeolites" as used herein includes all crystalline mesoporous
materials, such as zeolites, aluminophosphates, gallophosphates, zincophosphates,
titanophosphates, etc. Its mesostructure maybe in the form of ordered mesporosity (as in, for
example MCM-41, MCM-48 or SB A-15), non-ordered mesoporosity (as in mesocellular
foams (MCF)), or mesoscale morphology (as in nanorods and nanotubes). The notation
zeolite[mesostructure] is used to designate the different types of mesostructured zeolites.
"MOR" represents a mordenite which is a zeolite comprising approximately 2 moles
of sodium and potassium and approximately 1 mole of calcium in its orthorhombic crystal
structure. This term also includes the acidic form of MOR which may also be represented as
"H-MOR."
"MSU-S (MFI)" represents a mesoporous material made with nanosized zeolites with
a pore range of about 2-15 nm. The (MFI) refers to its structure.
"MSU-S (BEA)" represents a mesoporous material made with nanosized zeolites with
a pore range of about 1-15 nm. The (BEA) refers to its structure.
"PNA" represents a semicrystallized form of MCM-41.
"SBA-15" represents mesoporous (alumino) silicas with pore diameters up to 30 nm
arranged in a hexagonal manner and pore walls up to 6 nm thick.
The term "surfactant" is art-recognized and refers to any surface-active agent or
substance that modifies the nature of surfaces, often reducing the surface tension of water.
Cetyltrimethylammonium bromide is a non-limiting example of a surfactant.
"Y" represents a faujasite which is a zeolite comprising 2 moles of sodium and 1
mole of calcium in its octahedral crystal structure. This term also includes the acidic form of
Y which may also be represented as "H-Y."
The term "zeolite" is defined as in the International Zeolite Association Constitution
(Section 1.3) to include both natural and synthetic zeolites as well as molecular sieves and
other microporous and mesoporous materials having related properties and/or structures. The
term "zeolite" also refers to a group, or any member of a group, of structured aluminosilicate
minerals comprising cations such as sodium and calcium or, less commonly, barium,
beryllium, lithium, potassium, magnesium and strontium; characterized by the ratio
(Al+Si):0 = approximately 1:2, an open tetrahedral framework structure capable of ion
exchange, and loosely held water molecules that allow reversible dehydration. The term
"zeolite" also includes "zeolite-related materials" or "zeotypes" which are prepared by
replacing Si4+ or Al3+ with other elements as in the case of aluminophosphates (e.g., MeAPO,
SAPO, E1APO, MeAPSO, and E1APSO), gallophosphates, zincophophates, titanosilicates,
etc.
"ZSM-5" or "ZSM-5 (MFI)" represents a Mobil synthetic zeolite-5. This term also
includes the acidic form of ZSM-5 which may also be represented as "H-ZSM-5." The (MFI)
relates to its structure.
A comprehensive list of the abbreviations utilized by organic chemists of ordinary
skill in the art appears in the first issue of each volume of the Journal of Organic Chemistry;
this list is typically presented in a table entitled Standard List of Abbreviations.
For purposes of this invention, the chemical elements are identified in accordance
with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics,
67th Ed., 1986-87, inside cover.
Contemplated equivalents of the zeolitic structures, subunits and other compositions
described above include such materials which otherwise correspond thereto, and which have
the same general properties thereof (e.g., biocompatible), wherein one or more simple
variations of substituents are made which do not adversely affect the efficacy of such
molecule to achieve its intended purpose. In general, the compounds of the present invention
may be prepared by the methods illustrated in the general reaction schemes as, for example,
described below, or by modifications thereof, using readily available starting materials,
reagents and conventional synthesis procedures. In these reactions, it is also possible to make
use of variants which are in themselves known, but are not mentioned here.
Synthesis of Fully Crystalline Mesostructured Zeolites
In recent years, expertise has been gained in the synthesis of zeolites with desired
properties by the choice of the organic molecule used as structure directing agent (SDA),
control of the synthesis conditions, and post-synthesis treatments, van Bekkum, H., 5
Flanigen, E. M., Jacobs, P. A., Jansen, J. C. (editors) Introduction to Zeolite Science and
Practice, 2nd edition. Studies in Surface Science and Catalysis, 2001, 137; Corma, A., Chem.
Rev., 1997, 97, 2373-2419; Davis, M. E., Nature, 2002, 417, 813 - 821; Davis, M.E., et al.,
Chem. Mater., 1992, 4, 756-768; de Moor P-P.E.A. et al, Chem. Eur. J, 1999,5(7), 2083-
2088; Galo, J. de A. A., et al., Chem. Rev., 2002, 102, 4093-4138. At the same time, the
family of ordered mesoporous materials has been greatly expanded by the use of different
surfactants and synthesis conditions. Corma, A., Chem. Rev., 1997, 97, 2373-2419; Davis, M.
E., Nature, 2002, 417, 813 - 821; Galo, J. de A. A., et al., Chem. Rev., 2002, 102, 4093-4138;
Ying, J.Y., et al, Angew. Chem. Int. Ed, 1999, 38, 56-77. The family of fully crystalline
mesostructured zeolites disclosed herein is a one-phase hybrid material consisting of a
zeolitic structure with controlled mesoporosity, which bridges the gap between crystalline
microporous and amorphous mesoporous materials. In accordance with the instant invention,
a surfactant is employed to penetrate a fully crystalline zeolite structure forming pores, more
specifically, forming a plurality of mesopores throughout at least a portion of the volume of
the fully crystalline zeolite structure. An mesopore surface surrounds each mesopore within
the mesostructure. Full crystallinity includes all solids with one or more phases including
having repeating structures, referred to as unit cells, that repeat in a space for at least 10 nm.
A fully crystalline zeolite structure may have, for example, single crystallinity, mono
crystallinity, or multi crystallinity. Multi crystallinity includes all solids having more than
one phase having repeating structures, referred to as unit cells, that repeat in a space for at
least 10 nm. A fully crystalline zeolite is exposed to the surfactant, for a time, under
temperature, and pH conditions suitable to achieve a desired mesopore structure throughout
all or a portion of the volume of the fully crystalline zeolite. It is expected that any fully
crystalline inorganic material would have a similar structure, would similarly be produced,
and/or would similarly be employed where, for example, a zeolite, a fully crystalline zeolite,
or zeolites are described.
In contrast with Figure 1A, Figure 1B is a schematic illustration of a fully crystalline
mesostructured zeolite 200 of the instant invention, which features a fully crystalline zeolite
structure 205 with mesopores 210 penetrating throughout the volume of the zeolite structure
205. The mesostructure 215 that surrounds the mesopores 210 is fully crystalline. The pore
wall or interior wall between adjacent mesopores has a wall thickness 230. As illustrated in
Figure 1B, the mesostructure 215 and the mesopores 210 are viewed from a side 220 of the
zeolite structure 205. Although not depicted in this schematic illustration, the mesostructure
and the mesopores can be viewed from other sides of the mesostructured zeolite 200.
Referring now to Figures 1A and 1B, unlike the fully crystalline mesostructure 215 of
the fully crystalline mesostructured zeolite 200 of the instant invention, in the aggregated
crystalline mesoporous zeolite nuclei material 100, the pore walls that surround the
mesopore-sized pore volume 110 are discontinuous, featuring multiple zeolite nuclei crystals
e.g., 105a, 105b, 105c.
The synthesis of fully crystalline mesostructured zeolites is applicable to a wide
variety of materials. The first strategy is based on the short-range reorganization of a zeolite
structure in the presence of a surfactant to accommodate mesoporosity without loss of
zeolitic full crystallinity. A zeolite is added to a pH controlled solution containing a
surfactant. Alternatively, a zeolite is added to a pH controlled solution and thereafter a
surfactant is added. The pH controlled solution can be, for example, a basic solution with a
pH ranging from about 8 to about 12, or from about 9 to about 11, or alternatively, the basic
solution pH can be about 10. The strength of the base and the concentration of the basic
solution are selected to provide a pH within the desired range. Any suitable base can be
employed that falls within the desired pH range.
Suitable surfactants that can be employed in accordance with the invention include
cationic, ionic, neutral surfactants and/or combinations. The quantity of surfactant is varied
according to, for example, the surfactant and the zeolite that are mixed. For example, in one
embodiment, the weight of surfactant is about equal to the weight of zeolite added to the
solution. Alternatively, the weight of surfactant can be about half of the weight of zeolite
added to the solution.
The mixture is hydrothermally treated for a period of time that is selected to allow the
fully crystalline zeolite to achieve a desired mesostructure, for example, a H-Y[MCM-41] is
a fully crystalline acidic form of faujasite having a fully crystalline mesostructure
surrounding a hexagonal pore arrangement. Similarly, a H-Y[MCM-48] is a fully crystalline
acidic form of faujasite having a fully crystalline mesostructure surrounding a cubic pore
arrangement, and a H-Y[MCM-50] is a fully crystalline acidic form of faujasite having a
having a fully crystalline mesostructure surrounding a lamellar pore arrangement, etc.
Generally, the time and temperature are related such that a higher temperature requires a
shorter period of time to achieve a desired mesoporosity and a certain mesostructure as
compared to a lower temperature, which would require a relatively longer period of time to
achieve the same mesoporosity. Because time and temperature are related, any suitable
combination of time and temperature may be employed when hydrothermally treating the
mixture. For example, the temperature ranges from about room temperature to about 60 °C,
alternatively, the temperature ranges from 100 to about 200°C. Where the temperature is
about 60 °C or greater, the controlled temperature conditions take place under hydrothermal
conditions, for example, in a sealed reactor. The time ranges from about one hour to about
two weeks.
In two synthesis experiments, the parameters of time, temperature, zeolite type and
quantity, and surfactant type and quantity are kept constant, however, the pH in the first
synthesis is 9 and the pH in the second synthesis is 11. As a result of the different pH values
in the two synthesis experiments, the two fully crystalline zeolite mesostructures differ from
one another. Specifically, the fully crystalline zeolite mesostructure synthesized with the 9
pH solution features fewer mesopore surfaces, because fewer mesopores were incorporated
into the conventional fully crystalline zeolite, compared to the fully crystalline zeolite
mesostructure synthesized with the 11 pH, which has more mesopore surfaces, because the
higher base concentration resulted in increased mesoporosity.
In an exemplary synthesis, a zeolite is added to a diluted NH40H solution containing
cetyltrimethylammonium bromide (CTAB) surfactants. The mixture is hydrothermally
treated at about 100 to about 200 °C, about 120 to about 180 °C, about 140 to about 160 °C,
or about 150 °C for about 20 hr or overnight during which the zeolite structure undergoes
short-range rearrangements to accommodate the MCMA1 type of mesostructure. Higher
surfactant concentrations and longer hydrothermal treatments would produce mesostructured
zeolites with the MCM-48 type of mesostructure. After washing and drying, the surfactant is
removed by, for example, calcination or surfactant extraction. In one embodiment, the
resulting material is calcined in N2 at a maximum temperature from about 500 to 600°C, or at
about 550°C; and then in air for surfactant removal. The surfactant removal technique is
selected based, for example, on the time needed to remove all of the surfactant from the
mesostructured zeolites. This synthetic scheme could be used to produce mesostructured
zeolites with various zeolitic structures.
Without being bound to anyone theory, it is believed that the controlled pH solution
softens the conventional fully crystalline zeolite surface enabling the surfactant to penetrate
the zeolite creating the mesostructured zeolite. More specifically, the pH conditions that are
employed enable the surfactant to penetrate the structure of the zeolite however the pH
conditions do not dissolve the zeolite. As the surfactant penetrates the zeolite, forming
mesopores, the penetrated portion is exposed to the controlled pH solution and is softened,
enabling further penetration by the surfactant. The penetration continues in this fashion
throughout the volume of the zeolite. The penetration through the zeolite volume may be in
any single direction or in a combination of directions, for example, the penetration may be
through the x direction, the y direction, the z direction, or any combination thereof The
penetration direction or rate is not necessarily linear. Penetration may be ordered or
optionally the penetration and consequently the mesopores may be disordered or random.
Optionally, one or more of the mesopores intersect, interconnect, converge, and/or align,
which impacts the arrangement of the resulting mesoporous fully crystalline mesostructure.
The surfactant enables penetration into the fully crystalline zeolite, creating mesopores. The
type of surfactant determines, at least in part, the size of the mesopore including, for
example, the size of the mesopore diameter and/or the size of the mesopore cross section.
Penetration into the conventional fully crystalline zeolite is not observed where a controlled
pH solution, for example, a base having a pH of 10, held at controlled time and temperature
conditions is mixed with a zeolite without a surfactant.
Certain conventional fully crystalline zeolites are very stable (e.g., ZSM-5, MOR,
CHA etc.) and it is difficult to incorporate mesoporosity into these zeolites. In such cases,
strong base having, for example, a pH ranging from about 11 to about 14, or from about 12 to
about 13, or an acid, for example, HF having, for example, a pH ranging from about 2 to
about 6, or from about 3 to about 5, or at about 4, is necessary to dissolve silica and soften
the conventional fully crystalline zeolite surface to enable the surfactant to penetrate and
create mesopores through the fully crystalline zeolite.
Conventional fully crystalline zeolites with a dense structure (e.g. ZSM-5) are more
resistant to acids and basis relative to fully crystalline zeolites with less dense structures.
Zeolites with a low solubility (e.g. ZSM-5) and/or a dense structure are relatively stable with
respect to penetration by acids and bases, accordingly, a diluted tetramethyl ammonium
hydroxide (TMA-OH) having a pH ranging from about 10 to about 14 or a solution of acid,
for example hydrofluoric acid, HF, having a pH ranging from about 2 to about 6 can be used
instead of a dilute NH4OH solution, having a pH ranging from about 9 to about 10, in the
synthesis scheme. More specifically, base treatment alone, even at very high pH, is not
sufficient to soften some of the very stable zeolites. The acid HF dissolves silica and softens
the structure of the densely structured conventional fully crystalline zeolite (e.g., ZSM-5).
After softening the conventional fully crystalline zeolite by exposing it to HF, the pH is
increased by including a base solution having a pH from about 9 to about 11 and a suitable
surfactant is added in a quantity selected according to, for example, the quantity of zeolite
and the desired mesosporosity volume. The mixture is exposed to appropriate time and
temperature conditions to provide the desired mesoporosity and resulting mesostructure in a
fully crystalline mesostructured zeolite.
In another exemplary synthesis, a fully crystalline zeolite is added to an acid solution
having a pH from about -2 to about 2, or from about -1 to about 1, or at about 0, containing a
neutral surfactant, for example, PLURONIC(C) (available from BASF (Florham Park, NJ).
The mixture is exposed to appropriate temperature conditions for a period oftime selected to
achieve a desired mesostructure. The mixture can be held at room temperature and stirred for
from about 1 day to about 1 week. Alternatively, the mixture is hydrothermally treated. In
one embodiment, the mixture is hydrothermally treated at about 120°C for from about 4
hours to about 1 week. The resulting mesopores having a pore diameter measuring from
about 5 to 60 nm. An mesopore surface surrounds each mesopore of the mesostructure.
The mesopore size and architecture may also be conveniently tuned by well-known
techniques, such as the use of surfactants with different aliphatic chain lengths, non-ionic
surfactants, triblock copolymers, swelling agents, etc. For example, use of a surfactant with
longer chain length increases pore size and conversely, use of surfactant with a shorter chain
length decreases pore size. For example, use of a swelling agent will expand the surfactant
micelles. Any of these mesopore size and mesostructure architecture altering properties may
be used either alone or in combination. Also, post-synthesis treatments (e.g., silanation,
grafting, surface functionalization, ion-exchange, immobilization of homogeneous catalysts
and deposition of metal nanoclusters) could be employed to further improve the textural
properties of the materials and/or modify their surface chemistry.
Another aspect of the invention features mesostructures, e.g., as illustrated in Figure
1C. Such mesostructures can be achieved based on the dissolution of a zeolite in a pH
controlled medium, either in an acidic or basic medium, followed by hydrothermal treatment
in the presence of a surfactant. Suitable surfactants that may be employed include cationic,
ionic, neutral surfactants, and/or combinations of the cationic, ionic, and neutral surfactants.
The quantity of surfactant is varied according to, for example, the selected surfactant and the
selected zeolite. For example, the weight of surfactant can be about equal to the weight of
zeolite added to the solution, alternatively, the weight of surfactant can be about half of the
weight of zeolite added to the solution. Where the pH controlled medium is basic, the pH that
dissolves the zeolite ranges from about 10 to about 14. Where the pH controlled medium is
acidic, the pH that dissolves the zeolite ranges from about -2 to about 2, when using HF, the
pH range is from about 2 to about 6. Under these more extreme pH conditions, a mesoporous
solid was obtained wherein the pore walls were initially amorphous. The pore walls can later
be transformed to a zeolitic phase, with or without affecting the mesoporous structure. More
specifically, after the zeolite is exposed to this aggressive pH treatment, the pH is adjusted to
about 10 by adding, for example NH4OH, and surfactant (e.g., CTAB) to produce self-
assembling partially dissolved zeolites. This synthesis mixture can be hydrothermally treated
or stirred at room temperature over a period of time to obtain a highly stable mesoporous
amorphous aluminosilicate. More specifically, if the synthesis mixture is hydrothermally
treated at, for example, from about 100 to about 150°C, a highly stable mesoporous
amorphous aluminosilicate is obtained. Alternatively, the synthesis mixture is stirred at room
temperature for sufficient time (from about 4 hours to about 1 day) to obtain a highly stable
mesoporous amorphous aluminosilicate. The mesoporous amorphous aluminosilicate
maintains its mesoporosity after boiling for 48 hours under reflux conditions. The acidity of
the material produced is higher than that of amorphous mesoporous materials obtained from
non-zeolitic silica and alumina sources. Where the synthesis mixture is hydrothermally
treated for a longer period of time (from about 12 hours to about 2 weeks) a zeolitic
mesostructure is obtained. By adjusting the synthesis conditions (e.g., pH, time, temperature,
zeolite type, surfactant concentration) different zeolite nanostructures, for example,
nanotubes, nanorings, nanorods, nanowires, nanoslabs, nanofibers, nanodiscs, etc. can be
produced. Referring again to Figure 1C, a nanostructure including, for example, nanorods is
made from adjacent members (e.g., a first nanorod adjacent a second nanorod). Voids can be
formed between adjacent members (e.g., adjacent nanorods). Each nanostructure member
defines a plurality of pores (e.g., each nanorod has pores in its structure). Different members
can join together within a single nanostructure, for example, a nanorod may be adjacent a
nanoring.
Zeolitic nanorods (ZNRs) have been prepared by this approach in three steps: (i)
basic treatment of a zeolite in a pH controlled medium to partially dissolve the zeolite and
produce a suspension of amorphous aluminosilicate, (ii) pH adjustment and surfactant
addition to produce MCM-41, and (iii) hydrothermal treatment of the resulting solid at a
temperature typically ranging from about 100 to about 200°C for from about 12 hours to
about 2 weeks. During the last step, the MCM-41 (the hexagonal pore arrangement)
mesostructure is first transformed to MCM-48 (the cubic pore arrangement) and is then
transformed to MCM-50 (the lamellar pore arrangement), while the amorphous pore walls
are transformed to a crystalline zeolitic phase. MCM-50 is a lamellar structure and is a
precursor to zeolitic nanostructures including, for example, nanotubes, nanorings, nanorods,
nanowires, nanoslabs, etc. The specific nanostructure formed by using steps (i)-(iii) is
determined by the selected zeolite, surfactant, temperature, time, and pH. The zeolite and
other conditions can be selected to achieve a single nanostructure shape (e.g., all nanorod) or,
alternatively, multiple nanostructure shapes. Without being bound to any single theory, it
appears that nanostructures are achieved, at least in part, because the zeolite dissolved by a
pH controlled solution into a suspension of amorphous aluminosilicate retains some degree
of the zeolitic connectivity that is characteristic of a zeolite starting material. It is expected
that some of the 1R spectra bands characteristic of zeolites remain present in the dissolved
solution, i.e., in the suspension of amorphous aluminosilicate. In contrast, if rather than
dissolving a zeolite to produce a suspension of amorphous aluminosilicate an alumina, a
slilica, or an amorphous aluminosilicate were exposed to steps (ii)-(iii), described above, the
nanostructure fails to form. The building blocks of connectivity present in dissolved zeolite
solution appear to playa part in forming nanostructures.
Although the nanostructures are crystalline they are not fully crystalline. They have a
few units in one direction and are semi crystalline or are polycrystalline. Semi crystalline and
polycrystalline refers to, for example, nanosized crystals, crystal nuclei, or crystallites that,
for example, aggregate to form a solid. Unit cells are the simplest repeating unit in a
crystalline structure or crystalline material. Nanostructures have an open structure. They have
a high surface area due to an extended structure in the space as well as due to spaces between
multiple structures or voids within the structures themselves. Generally, these nanostructures
also have a high external surface area. In one embodiment, one nanostructure is adjacent
another nanostructure. Figure 1C depicts a TEM image of a nanosostructured zeolite of the
present invention where the nanostructure shape includes nanorods. The nanorods have a
thickness measuring about 5 run. As depicted, the nanorods sit adjacent one another and the
nanorods curve. The background of the curved rods seen in the TEM image is noise and it
should be ignored.
Zeolite-like materials, which represent a growing family of inorganic and
organic/inorganic molecular sieves, may also be used as precursors for the synthesis of
mesostructured zeolites, since the synthetic approaches described above may be adapted for a
wide variety of materials.
The mesostructured zeolites and methods ofmaking the mesostructured zeolites of the
instant invention utilize available, inexpensive, non-toxic, non-waste producing materials.
Previous attempts an improved porosity in zeolites required more steps, exercised limited
control on the final structure, and employed more expensive and toxic materials. The method
improves on the material cost and production efficiency of prior art processes, requiring
fewer steps to achieve improved porosity in zeolites. In addition, the methods of the
invention produce fully crystalline mesostructured zeolites. The methods of the invention
also produce nanostructured zeolites having a high surface area.
Structure of Mesostructured Zeolites
The hybrid structure of the mesostructured zeolites was studied via XRD. Figures 1D-
3 show the XRD patterns of H-Y[MCM-41], H-MOR[MCM-41], and H-ZSM-5[MCM-41],
respectively. As used herein, the naming convention for mesostructured zeolites, e.g., H-
Y[MCM-41] first includes the starting zeolite structure, e.g., H-Y and then, placed adjacent,
in brackets, is the name of the mesostructure, e.g., [MCM-41]. The mesostructured zeolite H-
Y[MCM-41] retains the full crystallinity of the zeolite H-Y, and features hexagonal pores
[MCM-41]. The fully crystalline mesostructure surrounds these hexagonal mesopores that
have been formed by the invention. Thus, the resulting structure is a fully crystalline H-Y
material that features an [MCM-41] type of mesostructure. For convenience, this is
designated as H-Y[MCM-41].
Figure ID depicts the X-ray diffraction pattern of the mesostructured zeolite H-
Y[MCM-41] and both the ordered mesostructure MCM-41 (revealed by the XRD peaks at
low angles) and the zeolitic fully crystalline structure H-Y are present. Figure 2 depicts the
X-ray diffraction pattern of the mesostructured zeolite H-MOR[MCM-41] and both the
ordered mesostructure MCM-41 (revealed by the XRD peaks at low angles) and the zeolitic
crystalline structure H-MOR are present. Figure 3 depicts the X-ray diffraction pattern of the
mesostructured zeolite H-ZSM-5 [MCM-41] and both the ordered mesostructure MCM-41
(revealed by the XRD peaks at low angles) and the zeolitic crystalline structure H-ZSM-5 are
present. Referring now to Figures 1D-3, very intense peaks, both at low and high 29° values
reveal both the ordered mesostructure and the zeolitic crystallinity of this family of materials.
In all cases, the peaks at low 20° values can be indexed to hexagonal symmetry indicating the
presence ofMCM-41, whereas the well-defined XRD peaks at high 29° values correspond,
respectively, to the zeolites Y, MOR and ZSM-5. This observation is remarkable since no
long-range crystallinity has been previously observed in mesoporous metal oxides and only
semicrystallinity (due to the presence of zeolite nanoclusters) has been achieved in thick-wall
mesoporous materials prepared using triblock copolymers. Kloetstra, K. R., et al, Chem.
Commun, 1997, 23, 2281-2282; Liu, Y. et al., Angew. Chem. Int. Ed. 2001, 7, 1255-1258;
On, D. T., et al., Angew. Chem. Int. Ed, 2001, 17, 3248-3251.
The connectivity of the mesostructured zeolites was studied by infrared spectroscopy
(FTIR) (See Figures 4-5). Figure 4 depicts FTIR characterization peaks for the fully
crystalline mesostructured zeolite H-Y[MCM-41], labeled Meso-H-Y, and zeolite Y.
Referring still to Figure 4, the FTIR spectra of the fully crystalline mesostructured zeolite H-
Y[MCM-41], labeled Meso-H-Y, is on the top and the FTIR spectra of the unmodified
conventional fully crystalline zeolite H-Y is on the bottom. Figure 5 depicts FTIR spectra of
H-Y[MCM-41] (upper top), H-MOR[MCM-41] (upper middle), H-ZSM-5 [MCM-41] (upper
bottom) and FTIR spectra of their fully crystalline zeolitic versions in conventional,
unmodified form, H-Y (lower top), H-MOR (lower middle), H-ZSM-5 (lower bottom). The
spectra of the fully crystalline mesostructured zeolite H-Y[MCM-41] is the upper top spectra
and the spectra of the unmodified fully crystalline zeolite H-Y is the lower top spectra. The
spectra of the fully crystalline mesostructured zeolite H-MOR[MCM-41] is the upper middle
spectra and the spectra of the unmodified fully crystalline zeolite H-MOR is the lower middle
spectra. The spectra of the fully crystalline mesostructured zeolite H-ZSM-5[MCM41] is the
upper bottom spectra and the spectra of the unmodified fully crystalline zeolite H-ZSM-5 is
the lower bottom spectra. In Figure 5 a match between each rally crystalline mesostructured
zeolite and its corresponding unmodified fully crystalline zeolite is observed, indicating the
zeolitic connectivity is present in fully crystalline mesostructured zeolites. Figure 5 shows a
remarkable match between the IR spectra of the fully crystalline mesostructured zeolites H-
Y[MCM-41], H-MOR[MCM-41], and H-ZSM-5[MCM-41] and those of the their
corresponding unmodified fully crystalline zeolitic versions, H-Y , H-MOR, H-ZSM-5,
contrary to highly stable AI-MCM-41, which presents only one IR broad peak, due to
imperfect zeolitic connectivity. Liu, Y., Pinnavaia, T.J., J. Mater. Chem., 2002, 12, 3179-
3190; Kloetstra, K. R., et al., Chem. Commun, 1997, 23, 2281-2282; Liu, Y. et al., Angew.
Chem. Int. Ed, 2001, 7, 1255-1258. The peak at 960 cm"1 in the H-Y[MCM-41]
mesostructured zeolite sample, characteristic of silanol groups on the wall surfaces, is an
additional evidence of the mesoporous/zeolitic hybrid nature of mesostructured zeolites.
Geidel, E., et al., Microporous andMesoporous Materials, 2003, 65, 31-42.
The presence of well-defined mesoporosity in mesostructured zeolites can be suitably
studied by nitrogen physisorption at 77 K. Storck, S., et al., Applied Catalysis A: General,
10 1998, 17, 137-146. Figures 6-8 show the nitrogen isotherms at 77 K of the fully
crystalline mesostructured zeolites, H-Y[MCM-41], H-MOR[MCM-41], and H-ZSM-
5[MCM-41], respectively, and their unmodified zeolitic versions, H-Y, H-MOR, and H-
ZSM-5. The presence of well developed narrow pore size diameter distribution mesoporosity
is evident in each mesostructured sample. The pore size of the mesoporosity is controlled
such that a diameter and or a cross sectional area of each of the mesopores in a specific fully
crystalline mesostructured zeolite fall within a narrow pore size diameter distribution. In
accordance with the fully crystalline mesostructured zeolites of the invention, in one
embodiment, more than 95% of the mesopores has a pore size (e.g., a diameter and/or a cross
sectional area) that falls within plus or minus 10% of the average pore size. In another
embodiment, more than 95% of the mesopores has a pore size (e.g., a diameter and/or a cross
sectional area) that falls within plus or minus 30% of the average pore size. In still another
embodiment, more than 95% of the mesopores has a pore size (e.g., a diameter and/or a cross
sectional area) that falls within plus or minus 75% of the average pore size. Each pore wall or
mesopore surface that surrounds a diameter controlled mesopore is substantially similar in
size. The fully crystalline mesostructured zeolites of the invention have controlled
mesoporosity pore size cross sectional area. Where the mesopores are substantially
cylindrical in shape in addition to having a pore size cross sectional area these pores have a
pore size diameter. However, where the shape of the mesopores are not cylinder like and are,
for example, slit shaped, worm-like, e.g., with a changing diameter throughout at least a
portion of the depth of the mesopore surface that surrounds an exemplary mesopore, or non
defined shapes then at least a portion of such a mesopore surface has a controlled mesopore
cross sectional area. The size of the mesopores is controlled by, for example, the selected
surfactant and/or quantity of surfactant used when making a fully crystalline mesostructured
zeolite from a conventional unmodified fully crystalline zeolite. Prior attempts to incorporate
mesostructures into zeolites have been unable to achieve such a controlled mesoporosity that
result in substantially all mesopores in a zeolite having a substantially similar size (e.g.,
diameter and/or cross sectional area) and a controlled pore arrangement (e.g., [MCM-41]
having a hexagonal pore arrangement). Rather, prior attempts to form mesostructures in
zeolites result in any or a combination of a broader pore size distribution ranging from small,
medium, to large size pores, different shaped pores, and uncontrolled arrangements.
A significant volume of mesoporosity can be introduced into the sample. For
example, referring to Figure 6, the mesopore volume roughly doubles when the zeolite is
mesostructured. In accordance with principles of the invention, in this example, the
unmodified zeolite H-Y had a mesopore volume of 30 cc/g whereas the fully crystalline
mesostructured zeolite labeled Meso-HY, which is HY[MCM-41], has a mesopore volume of
0.65 cc/g. Conventional zeolites adsorb nitrogen only at low pressures, producing type I
isotherms that are characteristic of microporous materials. Storck, S., et al., Applied
Catalysis A: General, 1998, 17, 137-146. However, the fully crystalline mesostructured
zeolites of the invention show sharp nitrogen uptakes at higher partial pressures (P/Po ~ 0.3),
which is a characteristic feature of mesostructured materials with narrow pore-size
distribution (pore diameter ~ 2.5 nm). Storck, S., et al., Applied Catalysis A: General, 1998,
17, 137-146. Figures 6-8 show similar results for fully crystalline mesostructured zeolites H-
Y[MCM-41], H-MOR[MCM-41], and H-ZSM-5 [MCM-41] and their unmodified
conventional zeolitic versions H-Y, H-MOR, and H-ZSM-5. Figure 9 depicts mesostructured
zeolite pore volumes (darker columns) of H-Y[MCM-41] (left), H-MOR[MCM-41] (center),
and H-ZSM-5[MCM-41] (right) and their zeolitic versions (lighter columns) of H-Y (left),
H-MOR (center), and H-ZSM-5 (right). Compared to conventional zeolites, the fully
crystalline mesostructured zeolites of the invention have more than double the pore volume
(see Figure 9) due to the incorporation of a well-developed, narrow distribution of pore-size
diameter mesoporosity. Referring still to Figure 9, the volume of mesoporosity that is
incorporated can be controlled. The fully crystalline mesostructured zeolite mesoporosity
volume is controlled by, for example, the quantity of surfactant added as a percentage of the
quantity of zeolite. Other factors that contribute to mesoporosity volume include the pH,
time, and temperature conditions employed. In one embodiment, the volume of the controlled
pH medium that is added is an amount suitable to achieve the desired surfactant
concentration in view of the amount of zeolite. The pore volume is expressed in cc/g, the
cubic centimeters of pores over the grams of the zeolite. The fully crystalline mesostructured
zeolite pore volume may range from about 0.05 cc/g to about 2 cc/g, or from about 0.5 cc/g
to about 1 cc/g. The mesopore size is controlled and the mesopore volume is controlled by
the type and the quantity of surfactant used to create the zeolite mesostructure from the
zeolite. The time and temperature conditions also contribute to the mesopore size and/or the
mesopore volume.
The mesostructured zeolites have sharper uptake at low partial pressures, which
indicates the presence of microporosity, and slightly higher pore size. As well known in
surfactant-templated mesoporous solids synthesis, the size of the mesopore in mesostructured
zeolites can be easily tuned or controlled by changing the length of the aliphatic chain of the
surfactant. Corma, A., Chem. Rev. 1997, 97, 2373-2419; Linssen, T., Cassiers, K., Cool, P.,
Vansant, E. P., Advances in Colloid and Interface Science, 2003, 103, 121-147; Ying, J.Y., et
al., Angew. Chem. Int. Ed., 1999, 38, 56-77. Optionally, the mesopore pore size diameter can
also be controlled by, for example, the choice of surfactant and/or the quantity of the
surfactant.
Previous attempts by others to prepare zeolitic mesostructured materials led to phase
separation into zeolite and amorphous mesoporous solids. Karlsson, A., et al., Microporous
and Mesoporous Materials, 1999, 27, 181-192; Huang L., et al., J. Phys. Chem. B. 2000,
104, 2817-2823. Moreover, some authors pointed out the difficulty of making thin-walled
mesoporous materials, such as MCM-41, with zeolitic walls, due to surface tension caused by
the high curvature of the structure. Yang, P., et al., Nature, 1998, 396, 152-155.
In one aspect of the invention, a fully crystalline mesostructured zeolite is produced,
as described above, by exposing a conventional zeolite to a suitable pH controlled solution
containing a suitable concentration of a selected surfactant under time and temperature
conditions desired to obtain the a desired mesopore size and mesopore volume. The fully
crystalline mesostructured zeolite retains substantially the same exterior surface contour
(e.g., has substantially the same external size and external shape) and covers substantially the
same perimeter as the unmodified conventional fully crystalline zeolite used to make the
fully crystalline mesostructured zeolite. Suitable unmodified conventional zeolites may range
in size from about 400 nm to about 5 microns. The conditions employed to form the
mesopores do not substantially change the external size, external shape or the perimeter of
the unmodified zeolite. The density of the fully crystalline mesostructured zeolite is less than
the density of the unmodified zeolite, however, the density difference is due to the zeolite
removed when the mesopores were formed. In addition, where the fully crystalline
mesostructured zeolite is produced from a fully crystalline conventional unmodified zeolite,
the fully crystalline mesostructured zeolite maintains the full crystallinity of the unmodified
conventional zeolite.
Where the unmodified conventional zeolite has a chemical composition in its
framework, after mesopores are formed in the conventional zeolite, the chemical composition
in the resulting fully crystalline mesostructured zeolite framework will remain substantially
the same as the chemical composition in the unmodified conventional zeolite framework that
was used as source material. The chemical composition of the unmodified conventional
zeolite can vary from the external surface (e.g., about the zeolite perimeter) to the inner core.
However, the chemical composition of unmodified conventional zeolite framework, whether
consistent or variable from the perimeter to the inner core of the zeolite, is unchanged when
the mesopores are formed in the zeolite. Thus, forming mesopores to create the fully
crystalline mesostructured zeolite does not chemically alter the framework of the
conventional zeolite. The zeolite stoichiometry is unchanged from the unmodified
conventional fully crystalline zeolite to the fully crystalline mesostructured zeolite.
Previous attempts by others to form mesostructures in zeolites has resulted in a
change in the chemical composition of the framework of the unmodified conventional
zeolite. For example, in zeolites containing Si and Al, prior methods treat the zeolite with a
base selected to remove more Al than Si from the zeolite. Where such dealumination
methods are employed, at least a portion of the chemical composition in the framework of the
zeolite changes, specifically, the tetracoordinated alumina ratio changes. Where the methods
of the invention are employed with a zeolite containing Si and Al, in a mesostructured zeolite
of the invention the alumina within the mesostructured zeolite framework remains
tetracoordinated.
Direct evidence for the hybrid single-phase nature of mesostructured zeolites was
obtained via transmission electronic microscopy (TEM). Figures 10a and 10b show two
details of the H-Y [MCM-41] mesostructured zeolite microstructure at different foci in which
both the crystallinity and ordered mesoporosity can be observed in a single phase. Additional
TEM images of mesostructured zeolites are depicted in Figures 11-12.
Additional evidence of the hybrid nature of mesostructured zeolites comes from
catalysis. The presence of mesopores, high surface area, and the thickness of the pore wall or
the interior wall between adjacent mesopores is (~2 nm). This must allow access to bulkier
molecules and reduce intracrystalline diffusion resistance in the fully crystalline
mesostructured zeolites of the invention as compared to conventional unmodified zeolites.
So, enhanced catalytic activity for bulky molecules must be observed in mesostructured
zeolites compared to zeolites.
For example, semicrystalline mesoporous materials, such as nanocrystalline
aluminosilicates PNAs and AI-MSU-S(MFI)' shows significantly lower activity for cumene
cracking (which is usually correlated to strong Bronsted acidity) than conventional H-ZSM-
5. Mesostructured zeolites, however, show even greater activity than zeolites, most likely due
to their fully zeolitic structure and the presence of mesopores. For example, H-ZSM-
5[MCM-41] converts 98% of cumene at 300oC whereas commercial H-ZSM-5 converts 95%
in similar conditions.
The anchoring of chemical species on mesostructured zeolites was confirmed by
Infrared Spectroscopy (FTIR). The pure chemical species to be anchored, the mesostructured
zeolites, and the species modified mesostructured zeolites prepared according the method
described herein were all ananlyzed by FTIR. The species modified mesostructured zeolites
exhibited the FTIR bands of the chemical species which did not disappear after washing the
samples.
Some of the chemical species anchored on mesostructured zeolites were used as
ligands for a homogeneous catalysts. This anchoring of a homogeneous catalyst was
confirmed by Infrared Spectroscopy (FTIR), and by catalytic testing of both the
homogeneous catalysts and the homogeneous catalysts anchored on the mesostructured
zeolite. These experiments were repeated after washing the samples and no major changes
were observed, indicating that this method is suitable for anchoring both chemical species
and homogeneous catalysts.
Applications
The unique structure of mesostructured zeolites will be useful to a variety of fields,
and should address certain limitations associated with conventional zeolites. As catalysis is
the most important field of application for zeolites, special emphasis is placed on the
catalytic applications of mesostructured zeolites, van Bekkum, H., Flanigen, E. M., Jacobs, P.
A., Jansen, J. C. (editors). Introduction to Zeolite Science and Practice, 2nd edition. Studies
in Surface Science and Catalysis, 2001, Vol. 137; Corma, A., Chem. Rev. 1997, 97, 2373-
2419; Davis, M. E., Nature 2002, 417, 813-821.
The combination of a mesostructure, a high surface-area, and controlled pore or
interior thickness (~ 2 ran) as measured between adjacent mesopores should provide for
access to bulky molecules and reduce the intracrystalline diffusion barriers. Thus, enhanced
catalytic activity for bulky molecules should be observed over mesostructured zeolites, as
compared to conventional zeolites. See Figures 13-14. Figures 13-20 include reactions with
1,3,5-triisopropylbenzene being catalytically cracked to form 1,3-diisopropyl benzene. The
1,3,5-triisopropylbenzene is representative of molecules present in crude oil and
l,3diisopropyl benzene is representative of a product within the gasoline range. These
experiments are a surrogate for molecules present in crude oil that are cracked to form
gasoline.
Figure 13 depicts the process of catalytic cracking of 1,3,5-triisopropyl benzene by
zeolite H-Y. Catalytic cracking is selectivity and/or efficiency limited, because diffusion is
limited by the small pore size of the zeolite H-Y. Because the conventional unconverted
zeolite crystal has limited diffusion, it is difficult for the reaction product, e.g., 1,3-
diisopropyl benzene, to exit the zeolite. As a result, over cracking occurs and light
compounds are formed resulting in excess formation of undesirable products cumene,
benzene, and coke. Figure 14 depicts the process of catalytic cracking of 1,3,5-triisopropyl
benzene by a mesostructured zeolite of the present invention. In contrast to catalytic cracking
with the unmodified conventional zeolite H-Y, the larger pore size, the controlled mesopore
volume, and the controlled interior or pore wall thickness present in the fully crystalline
mesostructured zeolite, facilitates the exit of desired products, e.g., 1,3- diisopropyl benzene,
from the mesostructure and over cracking that produces cumene, benzene and coke are
avoided. As a result, there is a higher catalytic cracking conversion of the desired product,
1,3-diisopropyl benzene.
Acid catalysts with well-defined ultralarge pores are highly desirable for many
applications, especially for catalytic cracking of the gas oil fraction of petroleum, whereby
slight improvements in catalytic activity or selectivity would translate to significant
economic benefits. Venuto, P. B., Habib, E. T., Jr. Fluid Catalytic Cracking with Zeolite
Catalysts. Marcel Dekker, New York, 1979; Harding, R. H., et al., Appl. Catal. A: Gen.,
2001, 221, 389-396; Degnan, T. F., et al., Microporous Mesoporous Mater., 2000, 35-36,
245-252. As a test reaction, we have examined the catalytic cracking of
l,3,5triisopropylbenzene (critical dimension ~ 0.95 nm) to produce 1,3-diisopropyl benzene.
Figure 15 depicts catalytic activity for 1,3,5-triisopropyl benzene cracking shown as percent
conversion to 1,3-diisopropyl benzene vs. time for the mesostructured zeolite H-Y[MCM-
41], which is labelled Meso-H-Y, the zeolite H-Y, and a conventional AI-MCM-41. Catalytic
cracking was performed when 50 mL/min of He saturated with 1,3,5-triisopropylbenzene at
120°C was flowed at 200 °C over 50 mg of each catalyst. The H-Y[ MCM-41]
mesostructured zeolite demonstrated superior catalytic activity for this cracking reaction after
400 min at 200°C (93% conversion) compared to the H-Y zeolite (71% conversion) and the
mesoporous AI-MCM-41 (39% conversion) (see Figure 15). This result was attributed to its
combination of strong acidity and mesostructured nature. The mesopores and the
mesostructure surrounding the mesopores greatly facilitated the hydrocarbon diffusion within
the H-Y[MCM-41] catalyst thereby improving conversion. The H-Y[MCM-41]
mesostructured zeolite is stable and maintains mesostructure integrity even under harsh
conditions. Figure 17 depicts the hydrothermal stability of H-Y[MCM-41], labelled Meso-H-
Y compared to the non-mesolytic zeolite AI-MCM-41. For example, the boiled
mesostructured zeolite H-Y[MCM-41], labelled Meso-H-Y, also maintained its
physicochemical integrity even after being boiled for several days, exhibiting a high 1,3,5-
triisopropylbenzene activity (87% conversion to 1,3-diisopropyl benzene after 400 min) even
after such severe treatment. The term boiled is used for convenience, however, the specific
treatment to the material includes suspending the solid in water and heating the water and
solid material under reflux conditions. See Figure 17. This outcome illustrated the superior
hydrothermal stability of H-Y[MCM-41] over the amorphous AI-MCM-41 catalyst, which
lost its activity and ordered mesostructure after exposure to similar conditions. These results
show that hydrothermally stable H-Y[MCM-41] is a crystalline material and its crystallinity
contrasts the amorphous AI-MCM-41 catalyst that structurally collapsed after boiling,
rendering it unable to convert appreciable quantities via catalytic cracking.
Figure 19 depicts catalytic activity for 1,3,5-triisopropyl benzene cracking shown as
percent conversion vs. time for H-ZSM-5[MCM-41], labeled Meso-H-ZSM-5, and its
zeolitic version, H-ZSM-5. A 50 mL/min of He flow saturated with 1,3,5-
triisopropylbenzene at 120°C was flowed at 200 °C over 50 mg of each catalyst, H-ZSM-
5[MCM-41] and H-ZSM-5. H-ZSM-5 is used as an important additive in cracking catalysts
to increase propylene production and improve octane number in gasoline. Degnan, T. F., et
al., Microporous Mesoporous Mater., 2000, 35-36, 245-252. However, due to its small pores,
H-ZSM-5 is inactive in 1,3,5-triisopropylbenzene cracking at 200°C ( 1,3-diisopropyl benzene after 400 min). The incorporation ofMCM-41 mesostructure in this
zeolite (H-ZSM-5[MCM-41]) successfully achieved substantial activity, with 40%
conversion of 1,3,5-triisopropylbenzene to 1,3-diisopropyl benzene after 400 min (see Figure
19). In this case, the activity was attributed to the mesopores and strong acidity of the
mesostructured zeolite.
More than 135 different zeolitic structures have been reported to date, but only about
a dozen of them have commercial applications, mostly the zeolites with 3-D pore structures.
Corma, A., Chem. Rev., 1997, 97, 2373-2419; Davis, M. E., Nature, 2002, 417, 813-821. The
incorporation of 3-D mesopores would be especially beneficial for zeolites with 1-D and 2-D
pore structures as it would greatly facilitate intracrystalline diffusion. Zeolites with 1-D and
2-D pore structures are not widely used, because the pore structure is less then optimal. To
illustrate the potential of mesostructure processing of zeolites with low pore
interconnectivity, H-MOR with 1-D pores were prepared with a MCM-48 mesostructure by
exposing the H-MOR zeolite with 1-D pores to a pH controlled solution in the presence of a
surfactant under suitable time and temperature conditions, described above. The resulting H-
MOR[MCM-48] with 3-D mesostructured structures was examined for die catalytic cracking
of 1,3,5-triisopropylbenzene at 200°C. Figure 18 depicts catalytic activity for
l,3,5triisopropyl benzene cracking shown as conversion to 1,3-diisopropyl benzene vs. time
for H-MOR[MCM-48] labeled Meso-HMOR, and its zeolitic version, H-MOR. A 50 mL/min
of He flow saturated with 1,3,5-triisopropylbenzene at 120°C was flowed at 200 °C over 50
mg of each catalyst, H-MOR[MCM-48] and H-MOR. Catalytic cracking with H-
MORfMCM-48] exhibited 50% conversion after 400 min, which was significantly higher
compared to the 7% conversion achieved by H-MOR (see Figure 18). Zeolites with 1-D pore
structures show a more dramatic improvement when exposed to the mesostructure process as
compared to the zeolites with 2-D pore structures, but this is to be expected, because the 1-D
pore structure zeolites begin with a more limited diffusion. When exposed to the
mesostructure process, zeolites with 2-D pore structures result in 3-D mesostructures.
Exposing 1-D and 2-D pore structure zeolites to the instant process for forming
mesostructures in fully crystalline inorganic material, e.g., zeolites, may increase the
usefulness of these otherwise underused zeolites.
Mesostructured zeolites not only showed much higher catalytic activity, but also
enhanced selectivity over zeolites. Referring now to Figure 16, a commercially available
zeolite H-Y was employed to catalytically crack 1,3,5-triisopropylbenzene. The resulting
products were 1,3-diisopropyl benzene, benzene, and cumene and the fractional composition
results were normalized to be 100%. The mesostructured zeolite labelled Meso-BY, which is
H-Y[MCM-41], was employed to catalytically crack 1,3,5-triisopropylbenzene under
identical conditions employed with H-Y. Increased production of 1,3-diisopropyl benzene
(about 110% of the 1,3-diisopropyl benzene produced with the zeolite H-Y) and decreased
production of benzene and cumene (about 75% of the benzene and cumene produced with the
zeolite H-Y) was observed. In this example, H-Y[MCM-41] mesostructured zeolite produced
only 75% of the benzene generated by the H-Y zeolite. See Figure 16. Benzene is a toxic
compound whose presence in gasoline is being increasingly restricted by legislation. Degnan,
T. F., et al., Microporons Mesoporous Mater., 2000, 35-36, 245-252. The benzene
production was even lower in the case of H-MOR[MCM-48], and was minimal in the case of
H-ZSM-5[MCM-41]. The decrease in benzene production has been observed in small zeolite
crystals, and was related to the intrinsic ability of crystals with higher surface areas to limit
successive cracking reactions. Al-Khattaf, S., et al., Appl. Catal. A: Gen, 2002, 226, 139-153.
It also reduced the formation of coke, which was the undesired end-product of the cracking
process that was responsible for catalyst deactivation. Thus, the mesostructured zeolites not
only provided for higher catalytic activity and selectivity, but also longer catalyst life time.
Zeolitic nanorods (ZNRs), another form of mesostructured zeolite, also enhance
catalytic activity by increasing active-site accessibility. The rod-shape ZNRs are only
nanometer-sized in diameter, so internal diffusional resistance is minimal. These new
mesostructured zeolites (also referred to as nanostructures) were tested as cracking catalysts
for the gas oil fraction of petroleum to assess their potential. Figure 20A depicts, on the left
hand side Y axis, the percent conversion of 1,3,5-triisopropylbenzene to 1,3-diisopropyl
benzene versus time for H-MOR[ZNR] and H-MOR. The ratio of benzene produced by
HMOR/ benzene produced by H-MOR[ZNR] as a function of time is also shown on the
secondary Y axis located on the right hand side of Figure 20A and an arrow is present on the
line that connects this data. A helium flow of 50 mL/min saturated with
l,3,5triisopropylbenzene at 120°C was introduced over 50 mg of each catalyst, H-
MORfZNR] and H-MOR, at 200°C.
In the cracking of 1,3,5-triisopropylbenzene, the conventional H-MOR zeolite
showed a low activity (7% conversion to 1,3-diisopropyl benzene after 400 min) due to its
medium-sized (0.65 x 0.70 ran), 1-D pores. In contrast, H-MOR[ZNR] achieved a much
higher catalytic activity under similar conditions (~ 52% conversion to 1,3-diisopropyl
benzene) (see Figure 20A). This significant increase in catalytic activity was attributed to
ZNRs' higher surface areas, readily accessible active sites, and improved intracrystalline
diffusivity.
Besides increased activity, ZNRs also showed improved selectivity due to their
nanostructured rod-shape morphology. For example, H-MOR[ZNR] produced 3 times less
benzene per mole of 1,3,5-triisopropylbenzene converted as compared to the commercial
zeolite H-MOR (see the secondary Y axis on the right hand side of Figure 20A). Benzene
may include, for example, benzene derivatives such as, for example, toluene, xylene, and
other related derivative compounds. This significant increase in selectivity also helped to
reduce coke formation, which has been a major problem with conventional cracking
catalysts, especially those containing I-D pores, such as mordenite.
The simple, inexpensive and generalized synthesis strategy described here allows for
the preparation of ZNR, a crystalline material with walls that are only several nanometers
thick (3-20 nm), in which nanorings and junctions are common. The novel synthesis strategy
was based on the "programmed" zeolitic transformation of mesoporous materials, which
avoided the typical drawbacks of nanoscaled zeolite synthesis (e.g., low yield, difficulty in
separation, and high pressure drops), and did not require the use of a layered precursor. The
unique crystalline structure of ZNRs provided for improved catalytic conversion of bulky
molecules by increasing the accessibility to its microporosity, while reducing interparticle
and intraparticle diffusion barriers.
Referring now to Figures 20B and 20C, mesostructured zeolites were tested for crude
oil refining via Microactivity Test (ASTM D-3907). This is a well known and widely
accepted technique to estimate the performance of FCC (Fluid Catalytic Cracking) catalysts.
Vacuum gas-oil was used as feed in a fluid-bed stainless steel reactor. The experiments were
conducted under identical conditions with mesostructured zeolites and their conventional
zeolites counterparts.
Figure 20B depicts microactivity test (MAT) results of a conventional fully
crystalline zeolite H-Y (Si/AI=15) and its fully crystalline mesostructured version H-
Y[MCM-41]. Microactivity test conditions included the reaction temperature of 500°C, the
catalyst contact time was 60 seconds, the catalyst charge was 1 grams, the catalyst/vacuum
gas oil ration was 2, the WHSV was 30 g/h/g. The conversion, specifically, how much of the
vacuum gas oil feed was converted into product, with all yield normalized to 100% for
comparison purposes, was for the unmodified fully crystalline zeolite H-Y: 61.22% and for
the fully crystalline mesostructured zeolite, H-Y[MCM-41]: 67.20%. Although not depicted
in Figure 20B, the results of this test provide an LPG fraction of H-Y of 17.45 % and LPG
fraction of H-Y[MCM-41] of 15.27 %.
Figure 20C depicts the composition of the LPG fraction obtained by Microactivity
test (MAT) of a conventional fully crystalline zeolite H-Y (Si/AI=15) and its fully crystalline
mesostructured version H-Y[MCM-41], described above in conjunction with Figure 20B.
The composition of the LPG fraction was analyzed to determine the components of the LPG
fraction. Where the fully crystalline zeolite H-Y was used the LPG fraction was 17.45 %.
Where the fully crystalline mesostructured zeolite H-Y[MCM-41] was used the LPG fraction
was 15.27 %. In addition, the fully crystalline mesostructured zeolites produced more olefins,
which are desired products. Referring now to the X-axis on Figure 20C the label C3 indicates
propane, the label C3= indicates propene, the label i-C4 indicates isobutane, the label n-C4
indicates normal butane, the label i-C4= indicates isobutene, and the label n-C4= indicates
normal butene. Specifically, the fully crystalline mesostructured zeolite produced increased
propene, isobutene, and normal butene in the LPG fraction then the unmodified fully
crystalline zeolite. Further, the fully crystalline mesostructured zeolite produced a lesser
fraction of LPG than with its counter part conventional unmodified fully crystalline zeolite.
The internal wall thickness of the fully crystalline mesostructured zeolite is less than the
internal wall thickness of the unmodified fully crystalline zeolite. Thus the thinner internal
walls in the fully crystalline mesostructured zeolites reduce hydrogen transfer reactions,
which are responsible for the undesired conversion of olefins to paraffins. Accordingly, an
increased number of desired olefins are produced where fully crystalline mesostructured
zeolites are used instead of conventional unmodified fully crystalline zeolites.
In the MET, generally, the samples were displayed in a fluidized-bed stainless steel
reactor. Reaction temperature was 500°C, the amount of catalyst was 3.0 g, the catalyst/oil
ratio was 2.0, the WHSV was 30 g/h/g, and the contact time was 60 seconds. These tests
showed that using H-Y[MCM-41] in place of conventional H-Y resulted in a 43% increase in
gasoline production, a 75% increase in propylene and a 110% increase in butenes.
Additionally, there is a 32% decrease in coke formation, a 23% decrease in Total Dry Gas,
and a 12% decrease in LPG (Liquified Petroleum Gases). The presence of mesopores in the
H-Y[MCM-41], which has at least double the surface area of H-Y, favours the cracking of
the larger molecules present in the crude oil, which cannot be transformed within the
micropores of conventional zeolites. Typically, conventional zeolites have pores measuring
about 0.7 nm, which are too small to efficiently process desirable products, for example,
alkyl benzene, contained in heavy crude oil fractions. Larger pore sizes are required to
facilitate improved surface area contact (including within the pore walls or mesopore
surfaces) with the hydrocarbon materials. For comparison, the diameter of each of the
mesopores, which are surrounded by the mesopore surfaces of the fully crystalline
mesostructure of the invention, can measure, e.g., about 2 nm. The increased production of
light olefins was related to the reduction of hydrogen transfer reaction due to the presence of
favorable interior or pore wall thickness in the fully crystalline mesostructured zeolites (~2
nm) as opposed to the thick crystals of conventional zeolites (-1000 nm). This interior or
pore wall thickness also results in reduction of overcracking, significantly reduces coke
formation, and reduces production of Total Dry Gas and LPG.
Pyrolysis of plastics has gained renewed attention due to the possibility of converting
these abundant waste products into valuable chemicals while also producing energy.
Williams, P. T. Waste Treatment and Disposal; John Wiley and Sons, Chichester, UK, 1998.
Acidic catalysts, such as zeolites, have been shown to be able to reduce significantly the
decomposition temperature of plastics and to control the range of products generated.
Williams, P. T. Waste Treatment and Disposal. John Wiley and Sons, Chichester, UK, 1998;
Park, D. W., et al, Polym. Degrad Stability 1999,65, 193-198; Bagri, R., et al., J. Anal.
Pyrolysis, 2002, 63, 29-41. However, the accessibility of the bulky molecules produced
during plastic degradation has been severely limited by the micropores of zeolites.
The catalytic degradation of polyethylene (PE) by commercially available zeolites
and their corresponding mesostructured zeolites was studied by thermal gravimetric analysis
(TGA). Figure 21 depicts the percentage of polyethylene (PE) weight lost vs. temperature for
the following mixtures of catalysts in weight ratio to PE. The curves labeled (A)-(G) depicts
results of the following degradation curves: (A): no catalyst, (B): H-ZSM-5:PE 1:2, (C): H-
ZSM-5[MCM-41]:PE 1:2, (D): H-ZSM-5:PE 1:1, (E) H-ZSM-5:PE 2:1, (F): H-ZSM-
5[MCM-41]:PE 1:1, and (G) H-ZSM-5[MCM-41]:PE 2:1. In all cases, fully crystalline
mesostructured zeolites allow for reduced decomposition temperatures compared to the
unmodified commercial zeolites (by ~ 35°C in the case of (C) H-ZSM-5[MCM-41] vs. (B)
H-ZSM-5), even at high catalyst:PE ratios (see Figure 21). In fact, referring to the curve
labelled (F), with a H-ZSM-5[MCM-41]:PE weight ratio of 1:1, a lower decomposition
temperature was achieved compared to that required by, referring to curve labeled (E), a
ZSM-5:PE weight ratio of2:1.
The large accessible surface area and ion-exchange properties of fully crystalline
mesostructured zeolites will also facilitate the surface functionalization, the immobilization
of homogeneous catalysts, and the deposition of metal clusters. Thus, fully crystalline
mesostructured zeolites also serve as a very useful catalyst support for a variety of reactions.
With their improved accessibility and diffusivity compared to conventional zeolites,
fully crystalline mesostructured zeolites may also be employed in place of unmodified
conventional zeolites in other applications, such as gas and liquid-phase adsorption,
separation, catalysis, catalytic cracking, catalytic hydrocracking, catalytic isomerization,
catalytic hydrogenation, catalytic hydroformilation, catalytic alkylation, catalytic acylation,
ion-exchange, water treatment, pollution remediation, etc. Many ofthese applications suffer
currently from limitations associated with the small pores of zeolites, especially when bulky
molecules are involved, van Bekkum, H., Flanigen, E. M., Jacobs, P. A., Jansen, J. C.
(editors), Introduction to Zeolite Science and Practice, 2nd edition. Studies in Surface
Science and Catalysis, Vol. 137, 2001; Corma, A., Chem. Rev., 1997, 97, 2373-2419; Davis,
M. E., Nature, 2002, 417, 813-821. Mesostructured zeolites present attractive benefits over
zeolites in such applications.
Organic dye and pollutant removal from water is of major environmental importance,
and represents the third major use of zeolites (accounting for 80 tons of zeolites per year).
Galo, J. de A. A., et al., Chem. Rev. 2002, 102, 4093-4138. However, most of the organic
dyes are bulky, which make their removal slow or incomplete, requiring a huge excess of
zeolites in the process. Fully crystalline mesostructured zeolites offer significant advantage
over unmodified conventional zeolites in organic dye and pollutant removal with their larger
surface area and pore size.
Kits
This invention also provides kits for conveniently and effectively implementing the
methods of this invention. Such kits comprise any of the zeolitic structures of the present
invention or a combination thereof, and a means for facilitating their use consistent with
methods of this invention. Such kits provide a convenient and effective means for assuring
that the methods are practiced in an effective manner. The compliance means of such kits
includes any means which facilitates practicing a method of this invention. Such compliance
means include instructions, packaging, and dispensing means, and combinations thereof. Kit
components may be packaged for either manual or partially or wholly automated practice of
the foregoing methods. In other embodiments involving kits, this invention contemplates a
kit including block copolymers ofthe present invention, and optionally instructions for their
use.
Exemplification
The invention now being generally described, it will be more readily understood by
reference to the following examples, which are included merely for purposes of illustration of
certain aspects and embodiments of the present invention, and are not intended to limit the
invention.
Example 1
Synthesis of H-YrMCM-41] - 0.79 g of zeolite H-Y (Zeolyst CBV-720 Si/Al=15) were
stirred in 50 mL of a 0.37 M NH4OH solution containing 0.55 g of CTAB, for 20 minutes,
after which time the synthesis mixture was hydrothermally treated at 150°C for 10 hours. The
solid was filtered, washed, and finally ramped in nitrogen at 5°C/min until 550°C, and then
switched to air for 4 hours. Similar conditions were used to calcine all of the samples.
Alternatively, 1 g of H-Y (Zeolyst CBV-720 Si/Al=15) was stirred for in 30 mL of a 0.09 M
tetramethylammonium hydroxide (TMA-OH) solution. Then 0.5 g of
cetyltrimethylammonium bromide (CTAB) was added. After 30 minutes of stirring the
suspension was hydrothermally treated for 20 hours at 150°C. Structural parameters are
presented in Table 1.
Example 2
Synthesis of H-MOR.[MCM-41] - 2.0 g of zeolite H-MOR (calcined Zeolyst CBV21A
Si/Al=10) was stirred in 50 mL of 0.27 M TMA-OH solution. Afterwards, 1.0 g of CTAB
was added. After other 30 minutes of stirring the synthesis solution was hydrothermally
treated at 150°C for 20 hours. Structural parameters are presented in Table 1.
Example 3
Synthesis of H-ZSM-5[MCM-41] - 1.0 g ofNRt-ZSM-5 (Zeolyst CBV3024E Si/AI=15) was
stirred in 50 mL of 0.8 M HF solution for 4 hours. This suspension was added to a solution
containing 0.69 g of CTAB, and stirred for 30 minutes. The resulting synthesis mixture was
basified by slowly adding 2.5 g of a 30% NH4OH solution. Finally, it was hydrothermally
treated at 150°C for 20 hours. Stlllctural parameters are presented in Table 1. The wall
thickness was determined by the standard method within the art by substracting the distance
between two pore centers (a0, obtained via X-ray diffraction) and the pore size (determined
by N2 adsorption).
Table 1. Structural parameters for the mesostructured zeolites.

Catalytic cracking of Cumene and 1.3.5-triisopropylbenzene - Catalytic tests were carried out
in a lab-scale packed-bed catalytic reactor connected to a gas chromatograph (Hewlett
Packard HP6890 Series) with a DB petrol (50 m x 0.2 mm x 0.5 microns) column. In all
cases, 50 mL/min of He were flowed through 50 mg of catalyst. For cumene cracking the gas
flow was saturated with cumene at room temperature and the reaction temperature was
300°C. For 1,3,5-triisopropylbenzene cracking the gas flow was saturated at 120°C and the
reaction temperatures were 300°C.
Example 5
Polyethylene (PE) degradation - An initial mass of~10 mg of catalyst:PE samples with ratios
1:2, 1:1, and 2:1 were ramped in a thermogravimetric analyzer (Perkin Elmer TGA7) at 10°C/
min in a 250 mL/min flow of He until 600°C. Results are depicted in Figure 21.
Example 6
Chemical species and homogeneous anchoring on mesostructured zeolites - The acid form of
the fully crystalline mesostructured zeolite with faujasite structure and MCM-41 architecture,
H-Y[MCM-41], (Si/Al~15), was ion exchanged in a 0.1 NFLOH solution for 24 h in order to
produce Nt4-Y[MCM-41]. The resulting material was ion-exchanged again in a 7.0 mM
NH2(CH2)2NMe3Cl solution for 24 h. After filtering and washing thoroughly, the sample was
dried at 60°C overnight. Finally, this amine functionalized mesostructured zeolite was added
to a 2.0 mM Rh(PPh3)3 solution (Wilkinson catalyst) for 24 h. After filtering and washing
thoroughly, the sample was dried at 60°C overnight. All the products, as well as the
quartenary amine and the Wilkinson catalyst, were analyzed by FTIR to confirm the presence
of the different species on the mesostructured zeolite even after thorough washing (see
Figure 22). Figure 22 depicts the FTIR spectra of a) H-Y[MCM-41], b) NH4-Y[MCM-41], c)
NH2(CH2)2NMe3Cl, d) NH2(CH2)2NMe3-Y[MCM-41], d) Rh(PPh3)3Cl, and e)
Rh(PPh3)3NH2(CH2)2NMe3-Y[MCM-41].
Example 7
Synthesis of Zeolitic NanoRods (ZNRs) - In a synthesis of nanostructured zeolites, 0.36 g of
NaOH are dissolved in 30 ml of water to produce a basic solution with a pH measuring 13.5.
Thereafter 1 g of H-Y (Zeolyst CBV 720) with an original Si/Al ratio of~15 is added to the
basic solution. After a 12 hours of stirring at room temperature, the zeolite and base mixture
had a pH measuring 11.5. Thereafter, 0.5 g ofCTAB (cetyl-trimethyl ammonium bromide)
was added to the zeolite and base mixture to produce a cloudy suspension. The cloudy
suspension was transferred into teflon-lined stainless steel autoclaves and treated
hydrothermally at 150°C under autogeneous pressure. The samples were collected at
different times, washed, dried and analyzed by X-ray Difraction, IR Spectroscopy, TEM, N2
adsorption at 17K, TGA and Elemental Analysis. In a similar synthesis procedure H-ZSM-
5[ZNR] was produced using H-Y (Zeolyst Si/Al ~ 80).
Incorporation by Reference
All of the patents and publications cited herein are hereby incorporated by reference.
Equivalents
Those skilled in the art will recognize, or be able to ascertain using no more than
routine experimentation, many equivalents to the specific embodiments of the invention
described herein. Such equivalents are intended to be encompassed by the following claims.
WE CLAIM :
1. A crystalline inorganic material, such as described herein, having long-range
crystallinity comprising a plurality of mesopores, wherein a cross-sectional area of each
of the plurality of mesopores is substantially the same.
2. The crystalline inorganic material as claimed in claim 1 wherein the plurality of
mesopores have a pore volume and the pore volume is controlled.
3. The crystalline inorganic material as claimed in claim 1, wherein the crystalline
inorganic material has an external surface contour substantially the same as the external
surface contour of the crystalline inorganic material prior to defining the plurality of
mesopores.
4. The crystalline inorganic material as claimed in claim 1, wherein the crystalline
inorganic material has a chemical composition framework substantially the same as the
chemical composition framework of the crystalline inorganic material prior to defining
the plurality of mesopores.
5. The crystalline inorganic material as claimed in claim 1, wherein the crystalline
inorganic material has a connectivity substantially the same as the connectivity of the
crystalline inorganic material prior to defining the plurality of mesopores.
6. The crystalline inorganic material as claimed in claim 1, wherein the crystalline
inorganic material has an improved intracrystalline diffusion compared to the
intracrystalline diffusion of the crystalline inorganic material prior to defining the
plurality of mesopores.
7. The crystalline inorganic material as claimed in claim 1, wherein an area of each
of the plurality of mesopores has a controlled cross sectional area range.
8. The crystalline inorganic material as claimed in claim 7, wherein the controlled
cross sectional area has a controlled distribution range.
9. The crystalline inorganic material as claimed in claim 7, wherein the controlled
cross sectional area has a diameter and each mesopore diameter has a controlled
distribution range.
10. The crystalline inorganic material as claimed in claim 7, wherein the controlled
cross sectional area has a diameter and each mesopore diameter falls within a 1 nm
distribution range.
11. A method of making a mesostructured inorganic material, the method comprising
the steps of:
a) providing an inorganic material having long-range crystallinity;
b) exposing the inorganic material to a pH controlled medium under a first
set of time and temperature conditions;
c) exposing the inorganic material to a surfactant under a second set of time
and temperature conditions; and
d) treating the inorganic material by controlling the first and second set of
time and temperature conditions to define a plurality of mesopores having a controlled
cross sectional area, forming a mesostructured inorganic material having long-range
crystallinity.
12. The method as claimed in claim 11 further comprising:
(b) selecting the pH controlled medium to control a pore volume, a diameter of
each of a plurality of mesopores, or a cross sectional area of each of a plurality of
mesopores; and
(c) selecting a quantity of the surfactant to control a pore volume, a diameter of
each of a plurality of mesopores, or a cross sectional area of each of a plurality of
mesopores.
13. The method as claimed in claim 11, wherein steps (b) and (c) occur
simultaneously.
14. The method as claimed in claim 11, wherein steps (b) and (c) occur sequentially.



One aspect of the present invention relates to crystalline inorganic materials having
long-range crystallinity and comprising a plurality of mesopores. A cross-sectional area of
each of the plurality of mesopores is substantially the same.
A method of producing a hydrocarbon material product is also disclosed. The method
comprises contacting a higher molecular weight hydrocarbon material with the crystalline
inorganic material under conditions of controlled temperature and pressure to produce a
hydrocarbon material product having a lower molecular weight.
A method of processing a polymer is also disclosed. The method comprises
contacting a polymer with the crystalline inorganic material and thermally treating the
polymer in the presence of the crystalline inorganic material.
A method of water treatment is further disclosed. The method comprises contacting
contaminated water with the crystalline inorganic material and removing contaminants from
the water with the crystalline inorganic material.

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3433-KOLNP-2006-ABSTRACT 1.1.pdf

3433-KOLNP-2006-ABSTRACT-1.2.pdf

3433-KOLNP-2006-AMANDED CLAIMS-1.1.pdf

3433-KOLNP-2006-AMANDED CLAIMS.pdf

3433-KOLNP-2006-ASSIGNMENT.pdf

3433-KOLNP-2006-CORRESPONDENCE 1.1.pdf

3433-KOLNP-2006-CORRESPONDENCE 1.1.pdf

3433-KOLNP-2006-CORRESPONDENCE-1.3.pdf

3433-KOLNP-2006-CORRESPONDENCE.1.2.pdf

3433-KOLNP-2006-CORRESPONDENCE.pdf

3433-KOLNP-2006-DESCRIPTION (COMPLETE) 1.1.pdf

3433-KOLNP-2006-DESCRIPTION (COMPLETE)-1.2.pdf

3433-KOLNP-2006-DRAWINGS 1.1.pdf

3433-KOLNP-2006-DRAWINGS-1.2.pdf

3433-KOLNP-2006-EXAMINATION REPORT.pdf

3433-KOLNP-2006-FORM 1 1.1.pdf

3433-KOLNP-2006-FORM 1-1.2.pdf

3433-KOLNP-2006-FORM 13.pdf

3433-KOLNP-2006-FORM 18 1.1.pdf

3433-kolnp-2006-form 18.pdf

3433-KOLNP-2006-FORM 2-1.1.pdf

3433-KOLNP-2006-FORM 2.pdf

3433-KOLNP-2006-FORM 3 1.2.pdf

3433-KOLNP-2006-FORM 3-1.3.pdf

3433-KOLNP-2006-FORM 3.1.1.pdf

3433-KOLNP-2006-FORM 3.pdf

3433-KOLNP-2006-FORM 5.pdf

3433-KOLNP-2006-FORM-27.pdf

3433-KOLNP-2006-GPA.pdf

3433-KOLNP-2006-GRANTED-ABSTRACT.pdf

3433-KOLNP-2006-GRANTED-CLAIMS.pdf

3433-KOLNP-2006-GRANTED-DESCRIPTION (COMPLETE).pdf

3433-KOLNP-2006-GRANTED-DRAWINGS.pdf

3433-KOLNP-2006-GRANTED-FORM 1.pdf

3433-KOLNP-2006-GRANTED-FORM 2.pdf

3433-KOLNP-2006-OTHERS 1.1.pdf

3433-KOLNP-2006-OTHERS 1.1.pdf

3433-KOLNP-2006-OTHERS-1.2.pdf

3433-KOLNP-2006-OTHERS.pdf

3433-KOLNP-2006-PETITION UNDER RULE 137.pdf

3433-KOLNP-2006-REPLY TO EXAMINATION REPORT 1.1.pdf

3433-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf


Patent Number 250467
Indian Patent Application Number 3433/KOLNP/2006
PG Journal Number 02/2012
Publication Date 13-Jan-2012
Grant Date 04-Jan-2012
Date of Filing 20-Nov-2006
Name of Patentee MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Applicant Address 5 CAMBRIDGE CENTER NE25-230, CAMBRIDGE, MA 02142-1493
Inventors:
# Inventor's Name Inventor's Address
1 YING JACKIE Y 9 FAIRLANE TERRACE, WINCHESTER, MA 01890
2 GARCIA-MARTINEZ JAVIER C/O PINTOR CABERA, 29 2G ALICANTE ES 03003
PCT International Classification Number C01B39/02; B01J20/18
PCT International Application Number PCT/US2005/014129
PCT International Filing date 2005-04-22
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/830,714 2004-04-23 U.S.A.