|Title of Invention||
LAYERED COMPOSITION AND PROCESSES FOR PREPARING AND USING THE COMPOSITION
|Abstract||A layered composition for catalyzing production alkenyl alkanoates, comprising: an inner core; and an outer layer comprising a refractory inorganic oxide, a fibrous component, an inorganic binder; and palladium and gold as catalytic components dispersed on the outer layer, characterized in that the inorganic oxide binder is derived from an inorganic binder precursor, wherein the inorganic binder precursor may decompose to form the same oxide as the refractory inorganic oxide.|
LAYERED COMPOSITION AND PROCESSES FOR
PREPARING AND USING THE COMPOSITION
FIELD OF THE INVENTION
 This invention relates to a layered composition, a process for preparing and a
hydrocarbon conversion process using the composition. The composition comprises an inner
core such as cordierite and an outer layer comprising an outer refractory inorganic oxide and a
fibrous component. The outer layer can optionally comprise a catalytic component dispersed
BACKGROUND OF THE INVENTION
 Numerous commercial processes are carried out using a catalyst. This is especially
true of various hydrocarbon conversion processes. These catalysts comprise one or more
catalytic element deposited onto a relatively high surface area support. Further, the catalytic
element or component can be evenly dispersed throughout the support, be dispersed on the
surface of the support or present as a band below the surface.
 The art also discloses catalysts containing an inert core or layer and an active outer
layer or shell. For example, US 3,145,183 discloses spheres having an impervious center and a
porous shell. Although it is disclosed that the impervious center can be small, the overall
diameter is 1/8" or larger. It is stated that for smaller diameter spheres (less than 1/8"),
uniformity is hard to control. US 5,516,740 discloses a thin outer shell of catalytic material
bonded to an inner core of catalytically inert material. The outer layer can have catalytic metals
such as platinum dispersed on it. The '740 patent further discloses that this catalyst is used in an
isomerization process. Finally, the outer layer material contains the catalytic metal prior to it
being coated onto the inner core.
 US 4,077,912 and US 4,255,253 disclose a catalyst having a base support having
deposited thereon a layer of a catalytic metal oxide or a combination of a catalytic metal oxide
and an oxide support. US 5,935,889 discloses a catalyst which comprises a catalytically inert
core material on which is deposited and bonded a thin shell of material containing active sites.
Finally, US 6,177,381 discloses a layered catalyst composition containing an inner core, an outer
layer bonded to the inner core and where the outer layer has dispersed thereon a platinum group
metal, a promoter metal and a modifier metal.
 One problem associated with the layered compositions of the prior art is that the
strength or attrition resistance was not sufficient for certain applications. Applicants have
discovered that adding a fibrous component to the outer layer greatly increases its strength. The
fibrous components can be either inorganic fibers such as silica or mullite fibers or organic fibers
such as carbon fibers.
SUMMARY OF THE INVENTION
 One embodiment of the invention is a layered composition comprising an inner core
and an outer layer comprising a refractory inorganic oxide and a fibrous component.
 Another embodiment of the invention is a process for preparing the layered
composition described above, the process comprising coating an inner core with a slurry
comprising the outer refractory inorganic oxide, a fibrous component, an inorganic binder, an
organic bonding agent and a solvent to give a coated core; and calcining the coated core at a
temperature of at least 200°C for a time sufficient to bond the outer layer to the inner core and
provide a layered composition.
 Yet another embodiment of the invention is a hydrocarbon conversion process
comprising contacting a hydrocarbon with the layered composition described above at conversion
conditions to give a converted product.
 These and other objects and embodiments will become clearer after a detailed
description of the invention.
DETAILED DESCRIPTION OF THE INVENTION
 One element of the layered composition of the present invention is an inner core. One
characteristic of the materials which can be used for the inner core is the ability to be formed into
a desired shape. Examples of materials which can be used include but are not limited to metals,
refractory inorganic oxides and silicon carbide. Refractory inorganic oxides are preferred with
non-limiting examples being aluminas, cordierite, mullite, montmorillonite, silica, zirconia,
titania and mixtures thereof. Aluminas include gamma, theta, delta and alpha alumina. A
preferred inorganic oxide is cordierite. When the inner core is a refractory inorganic oxide, it is
necessary that it be different from the outer layer refractory inorganic oxide.
 Further, when the outer layer will have additional components, e.g. metals or metal
oxides, which are deposited thereon by impregnation means, it is preferred that the inner core
have a lower adsorptive capacity relative to the outer layer. This adsorptive capacity is with
respect to solvents which may be used to impregnate the outer layer with a compound of a
catalytic component. The inner core should also have a substantially lower capacity for the
compounds themselves versus the outer layer.
 These materials which form the inner core can be formed into a variety of shapes such
as pellets, extrudates, spheres, hollow tubes or irregularly shaped particles although not all materials
can be formed into each shape. Preparation of the inner core can be done by means known in the
art such as oil dropping, pressure molding, metal forming, pelletizing, granulation, extrusion,
rolling methods and marumerizing. A spherical inner core is preferred. The inner core whether
spherical or not has an effective average diameter of about 0.05 mm to about 15 mm and preferably
from about 0.5 mm to about 10 mm. For a non-spherical inner core, effective diameter is defined
as the diameter the shaped article would have if it were molded into a sphere. Once the shaped
inner core is formed it is optionally calcined at a temperature of about 400°C to about 1500°C.
 The inner core is now coated with a layer of a refractory inorganic oxide which is
different from the inorganic oxide which may be used as the inner core and will be referred to as the
outer refractory inorganic oxide. This outer refractory oxide is one which has good porosity, has a
surface area of at least 2 m2/g, and preferably at least 20 m2/g and most preferably at least 30 m2/g,
an apparent bulk density of about 0.2 g/ml to about 1.8 g/ml. Non-limiting examples of the
refractory inorganic oxides which can be used are gamma alumina, delta alumina, eta alumina, theta
alumina, silica/alumina, zeolites, non-zeolitic molecular sieves (NZMS), titania, zirconia and
mixtures thereof. It should be pointed out that silica/alumina is not a physical mixture of silica and
alumina but means an acidic and amorphous material that has been cogelled or coprecipitated. This
term is well known in the art, see e.g., US 3,909,450, US 3,274,124 and US 4,988,659, all of which
are incorporated by reference. Examples of zeolites include, but are not limited to, zeolite Y,
zeolite X, zeolite L, zeolite beta, ferrierite, MFI, UZM-4(see US 6,776,975), UFI, UZM-8(US
6,756,030), UZM-9(US 6,713,041), mordenite and erionite. Non-zeolitic molecular sieves
(NZMS) are those molecular sieves which contain elements other than aluminum and silicon and
include silicoaluminophosphates (SAPOs) described in US 4,440,871, ELAPOs described in US
4,793,984, MeAPOs described in US 4,567,029 all of which are incorporated by reference.
Preferred refractory inorganic oxides are gamma, eta alumina and zirconia.
 The refractory inorganic oxide is applied to the inner core by first forming a slurry
comprising the refractory inorganic oxide. The slurry is formed by admixing a solvent with the
refractory inorganic oxide to form a mixture and milling the mixture for a time sufficient to form a
slurry. The solvent which is usually used is water although organic solvents can also be used. The
mixture can also contain an agent which will aid in forming the slurry such as but not limited to
nitric acid, hydrochloric acid, sulfuric acid and acetic acid. The slurry will also contain an inorganic
binder precursor which is usually, a sol, a gel or a compound of a metal which on heating will
decompose to form an inorganic oxide binder. The inorganic binders which can be used include
but are not limited to alumina, silica, zirconia, titania, aluminum phosphate, etc. Nonlimiting
examples of binder precursors which can be added to the slurry are: ZrO(C2H3O2)2; ZrO(NO3)2;
ZrO (OH)Cl- nH2O; zirconia sol; ZrOCO3; ZrO (OH)2; Zr (C5HsO2)4; Zr(SO4)2-4H2O; alumina sol;
silica sol; aluminum nitrate and boehmite. Although in some cases it is preferred that the binder
give the same refractory oxide as the outer layer oxide, generally any inorganic binder can be used
with any outer layer refractory oxide. For example, an alumina binder can be used when the outer
layer is a zeolite, titania, silica or alumina. However, it has been found that when zirconia is the
outer refractory inorganic layer, it is preferred to have a zirconia binder. The amount of inorganic
binder precursor present in the slurry is that amount which will provide from about 1 wt.% to about
99 wt.% inorganic binder on the deposited outer layer. Preferably the amount of binder precursor
present is that amount which will give from 2 to 40 wt.% of the outer layer of inorganic binder and
most preferably the amount which will provide from 5 to 30 wt.% of the outer layer.
 Another necessary component of the slurry is a fibrous component. Suitable fibrous
components include those that comprise fibers that are elongated, thread-like objects or structures
or filaments. The types of fibers which can be used include both inorganic and organic fibers either
of which can be natural or synthetic. Generally fibers can comprise a large array of materials
including without limitation glasses, minerals, metal oxides, ceramics, metals, polymers and
carbons. Specific examples of inorganic fibers include but are not limited to titania fibers,
potassium titanate fibers, zirconia fibers, mullite fibers, alumina fibers, silicon carbide fibers, glass
wool, boron fibers, aluminum fibers, silica fibers and cordierite fibers. A preferred fiber which is
mostly silica (60% SiO2, 33% CaO and 6% MgO) is Superwool™ manufactured and sold by
Thermal Ceramics. Nonlimiting examples of organic fibers are graphite fibers, carbon fibers and
polymeric fibers such as polyethylenes, polyesters, polyurethanes, polyamides, aromatic polyamides
(e.g. Kevlar™), polystyrenes (e.g. syndiotactic polystyrene), polytetrafluoroethylenes (e.g.
Teflon™). Furthermore, combinations of materials may be used in the fibers as well as
combinations of fibers in the fibrous component. It should be pointed out that when organic fibers
are used, the subsequent treating temperatures and the process temperature that it will be used at
must be below the combustion temperature of the organic fibers. Obviously the inorganic fibers
will not combust, but the operating temperature must be below its melting temperature.
Furthermore, fibers may be further treated (e.g. coated) to accentuate desirable characteristics (e.g.
treated to increase decomposition or melting temperature). While the fibrous component may
include fibers that are woven, braided or otherwise entangled or connected in an unwoven manner,
the fibers may also be free of connections with other fibers.
 Although the length of the fibers is not critical, usually the fibers have a length from
about 1 to about 10,000 micrometers, preferably from about 2 to about 1,000 micrometers and most
preferably from about 5 to about 300 micrometers. The fibers also have varying diameters which
again is not critical. Smaller diameter fibers are more easily dispersed and thus are preferred. Since
both the length and diameter of the fibers can be varied, a preferred length/diameter (L/D) ratio can
be determined experimentally. This L/D ratio is different for different fibers.
[0017) The amount of fibers which can be added to the slurry can vary considerably and is
usually that amount which will give from about 1 to about 30 wt.% of the final layer weight,
preferably from about 1 to about 20 wt.% and most preferably from about 3 to about 10 wt.%.
 It is also necessary that the slurry contain an organic bonding agent which aids in the
adhesion of the layer material to the inner core. Examples of this organic bonding agent include but
are not limited to polyvinyl alcohol (PVA), hydroxy propyl cellulose, methylcellulose and carboxy
methylcellulose. The amount of organic bonding agent which is added to the slurry will vary
considerably from about 0.1 wt. % to about 5 wt. % of the slurry.
 As stated, the slurry is milled using any of a variety of mills known in the art such as
ball milling, impact milling, etc. Milling is carried out to ensure adequate blending of the various
components and to optionally reduce the particle size of the refractory inorganic oxide powder
and/or fibers. Milling is usually carried out for a time of about 2 to about 8 hours.
 Coating of the inner core with the slurry can be accomplished by means such as rolling,
dipping, spraying, etc. One preferred technique involves using a fixed fluidized bed of inner core
particles and spraying the slurry into the bed to coat the particles evenly. The thickness of the layer
can vary considerably, but usually is from about 40 to about 400 micrometers preferably from about
40 to about 300 micrometers and most preferably from about 50 to about 200 micrometers. It
should be pointed out that the optimum layer thickness depends on the use for the catalyst and the
choice of the outer refractory oxide. Once the inner core is coated with the layer of outer refractory
inorganic oxide, the resultant layered composition is dried at a temperature of about 100°C to about
150°C for a time of about 1 to about 24 hours and then calcined at a temperature of at least 200°C
for a time of about 0.5 to about 10 hours to effectively bond the outer layer to the inner core and
provide a layered composition. The calcination conditions are chosen to not only effectively bond
the outer layer to the inner core but to optimize the characteristics of the outer layer, e.g. surface
area of the layer, integrity of the fibers, pore volume of the inorganic oxide etc. As stated above, if
organic fibers are used the calcination temperature must be below their combustion temperature.
Thus, preferred calcination temperatures are from about 200°C to about 1500°C and most preferably
from about 400°C to about 1100°C. Finally, the drying and calcining steps can be combined into
one step. It should also be pointed out that in some cases it may be necessary to carry out the
layering process more than once in order to obtain the desired layer thickness. Intermediate
calcining steps may not be necessary with a drying step being sufficient to ensure that the first layer
does not dissolve during the subsequent layering step.
 In one embodiment of the invention, the layered composition comprises more than one
layer. Successive layers are applied to the coated composition after the first (or subsequent layer)
has been calcined. Coating of a layered core is carried out as described above for the first layer.
The second layer of refractory inorganic oxide is different from the first layer and will be different
from the third layer (if any), although the first and third layer can be the same inorganic oxide.
Thus, it is only necessary that adjacent layers be of different refractory inorganic oxides. The
thickness of each layer is as stated for the first layer and the number of additional layers can vary
from 1 to about 5 layers or more.
 As stated the use of fibers in the outer layer greatly improves the strength or attrition
resistance of the resultant layered composition. The strength of the layered composition was
determined by measuring its impact breakage (IB). Impact breakage was determined by taking an
amount of layered composition (about 50 cc) after calcination, placing them in a flat drum and
rotating the drum at 25 rpm for 10 minutes. The fines were collected, weighted and the IB
determined from the following equation:
IB = (Weight of Fines / Total Weight of Layered Composition) x 100%
 The layered composition of the invention will have an IB of preferably less than about
10 wt.%, more preferably less than about 5 wt.% and most preferably less than about 3 wt.%.
Ranges within the above stated ranges are also contemplated.
 Although the layered composition described above can be used as is to catalyze various
reactions, it is usually used as a support for various catalytic components. These catalytic
components are selected from the group consisting of Groups 3-12 of the Periodic Table of the
Elements using the IUPAC system of numbering the groups and as set forth at
http://pearl 1 .lanl.gov/periodic/default.htm. Preferred catalytic elements or metals are the noble
metals or platinum group metals which include platinum, palladium, rhodium, ruthenium, osmium
and iridium. Gold and silver are also preferred catalytic metals. Combinations of catalytic
components are also preferred, such as palladium used in combination with gold and/or rhodium.
 These catalytic metal components can be deposited on the layered support in any
suitable manner known in the art. One method involves impregnating the layered composition or
support with a solution (usually aqueous, although organic solvents can be used) of a decomposable
compound of the catalytic metal or metals. By decomposable is meant that upon heating the metal
compound is converted to the metal or metal oxide with the release of byproducts. Examples of the
compounds which can be used include without limitation chlorides, other halides, nitrates, nitrites,
hydroxides, oxides, oxalates, acetates, sulfates and amines. Illustrative examples of decomposable
compounds of the platinum group metals are chloroplatinic acid, ammonium chloroplatinate,
bromoplatinic acid, dinitrodiamino platinum, sodium tetranitroplatinate, rhodium trichoride, hexa-
amminerhodium chloride, rhodium carbonylchloride, sodium hexanitrorhodate, chloropalladic acid,
palladium chloride, palladium nitrate, diamminepalladium hydroxide, tetraamminepalladium
chloride, hexachloroiridate (IV) acid, hexachloroiridate (III) acid, ammonium hexachloroiridate
(III), ammonium aquohexachloroiridate (IV), ruthenium tetrachloride, hexachlororuthenate, hexa-
ammineruthenium chloride, osmium trichloride and ammonium osmium chloride. Examples of
other palladium compounds include but are not limited to Na2PdCl4, Pd(NH3)4(NO2)2,
Pd(NH3)4(OH)2, Pd(NH3)4(NO3)2, Pd(NH3)4(OAc)2, Pd(NH3)2(OAc)2, Pd(OAc)2 in KOH and/or
NMe4OH and/or NaOH, Pd(NH3)4(HCO3)2 and palladium oxalate. Examples of gold and silver
compounds include but are not limited to AuCl3, HAuCl4, NaAuCl4, KAuO2, NaAuO2,
NMe4AuO2, Au(OAc)3, HAu(NO3)4, AgNO3, AgC2H3O2 and AgClO3. Solubility modifiers may be
utilized to aid in solubilizing the decomposable compound of the catalytic metal or metals. For
example, acids or bases may be used to facilitate the catalytic compound going into solution. In one
embodiment, KOH and/or NMe4OH is used in combination with Au(OAc)3 or nitric acid is used
 Multiple solutions containing the catalytic compounds may be impregnated onto the
layered composition or support simultaneously (e.g. co-impregnation) or sequentially and may be
impregnated through the use of one or multiple solutions.
 One or more calcining steps may be used, such that at any point after at least one
catalytic component compound is contacted with the layered composition or refractory inorganic
oxide, it may be calcined. For example, the calcining step is carried out at a temperature in the
range of about 100°C to about 700°C, preferably between about 200°C and about 500°C in a
non-reducing atmosphere. Calcination times may vary but preferably are between about 1 and 5
hours. The degree of decomposition of the catalytic component compound depends on the
temperature used and length of time the impregnated catalyst is calcined and can be followed by
monitoring volatile decomposition products.
 Preferably, the last calcining step occurs before contact of the gold catalytic
component to a zirconia containing layered composition. Alternately, calcining of a zirconia
containing support composition containing gold is conducted at temperatures below about
300°C. Exemplary protocols including a calcining step include: a) impregnating with palladium
followed by calcining followed by impregnating with gold; b) co-impregnating palladium and
rhodium followed by calcining followed by impregnating with gold; c) impregnating with
palladium followed by calcining followed by impregnating with rhodium followed by calcining
followed by impregnating with gold; or d) impregnating with palladium and rhodium, followed
by impregnating with gold, followed by calcination.
 One impregnation procedure involves the use of a steam-jacketed rotary dryer. The
layered composition is immersed in the impregnating solution containing the desired metal
compound(s) contained in the dryer and the support is tumbled therein by the rotating motion of the
dryer. Evaporation of the solution in contact with the tumbling support is expedited by applying
steam to the dryer jacket. The resultant composite is allowed to dry under ambient temperature
conditions, or dried at a temperature of about 80° to about 110°C, followed by calcination, thereby
converting the metal compound to the metal or metal oxide.
 Another impregnation procedure is spray impregnation which is well known in the art
and is presented here only for completeness. The layered composition is loaded into a drum and a
spray nozzle is inserted into the opening of the drum. The support is tumbled and the metal
containing solution is delivered through the spray nozzle for 15 to 30 minutes. The amount of
solution can be varied to determine the depth of penetration into the support. The support is dried
at 110°C to 150°C and additional metals can be added by repeating the above procedure or the
support can be calcined to convert the metal compounds to the metal or metal oxide.
 The dispersion of the catalytic metals can either be done as described above after the
refractory inorganic oxide has been applied to the inner core or the refractory inorganic oxide can
first be impregnated with the desired solution, dried, calcined, slurried and then applied to the inner
core. If the layered composition contains more than one layer, all the layers need not have catalytic
metals dispersed thereon. For example, the first layer can have one or more catalytic metal
dispersed thereon, while the second layer does not have any catalytic metals thereon or vice versa.
Alternatively, the first layer can have one or more catalytic metal while the second layer has
different catalytic metal(s).
 In addition to the catalytic components, various promoters and modifiers can also be
dispersed on the layered composition. Promoters and modifiers can be any elements selected from
the group consisting of alkali metals, alkaline earth metals, tin, germanium, rhenium, gallium,
bismuth, lead, indium, cerium, zinc, boron and mixtures thereof. One preferred promoter for use in
vinyl acetate production is an alkali metal, which may be provided in the form of an acetate such as
KOAc. The addition of the alkali metal may be referred to as activating the catalyst.
 The promoter and modifier components can be dispersed onto the layered support in the
same way as described for the catalytic component. All the components can be impregnated using
one common solution or they can be sequentially impregnated in any order, but not necessarily with
equivalent results. Additionally, these promoters and modifiers can be present in one layer, but not
in another layer. They can also be present in a layer where there are no catalytic metals or only in
layers where there are catalytic metals.
 When it is stated that the catalytic components, promoters and modifiers are "dispersed
or deposited on" the outer layer it is meant that they can be dispersed either on the surface of the
layer, throughout the layer or even below the outer surface in a tight band. It should be pointed out
that when the inner core comprises a material that has some adsorptive property, a small fraction of
the catalytic component, promoter and/or modifier can be found on or throughout the core.
 The catalysts of the present invention may be utilized to produce alkenyl alkanoates
from an alkene, alkanoic acid and an oxygen containing gas in the presence of a catalyst.
Preferred alkene starting materials contain from two to four carbon atoms (e.g. ethylene,
propylene and n-butene). Preferred alkanoic acid starting materials used in the process of this
invention for producing alkenyl alkanoates contain from two to four carbon atoms (e.g., acetic,
propionic and butyric acid). Preferred products of the process are vinyl acetate, vinyl propionate,
vinyl butyrate, and allyl acetate. The most preferred starting materials are ethylene and acetic
acid with the vinyl acetate being the most preferred product. Thus, the present invention is
useful in the production of olefinically unsaturated carboxylic esters from an olefinically
unsaturated compound, a carboxylic acid and oxygen in the presence of a catalyst. Other
methods of making alkenyl alkanoates may be found in U.S. Application No. 10/993,507, which
incorporated by reference.
 When vinyl acetate is produced using the catalyst of the present invention, a stream of
gas, which contains ethylene, oxygen or air, and acetic acid is passed over the catalyst. The
composition of the gas stream can be varied within wide limits, taking into account the zone of
flammability of the effluent. For example, the molar ratio of ethylene to oxygen can be about 80:20
to about 98:2, the molar ratio of acetic acid to ethylene can be about 100:1 to about 1:100,
preferably about 10:1 to 1:10, and most preferably about 1:1 to about 1:8. The gas stream may also
contain gaseous alkali metal acetate and/or inert gases, such as nitrogen, carbon dioxide and/or
saturated hydrocarbons. Reaction temperatures which can be used are elevated temperatures,
preferably those in the range of about 125-220°C. The pressure employed can be a somewhat
reduced pressure, normal pressure or elevated pressure, preferably a pressure of up to about 2026
kPa (20 atmospheres gauge).
 For a vinyl acetate catalyst according to the present invention preferably comprises
between about 1 to about 10 grams of palladium, and about 0.5 to about 10 grams of gold per
liter of catalyst. The amount of gold is preferably from about 10 to about 125 wt % based on the
weight of palladium. Further, the catalyst preferably contains about 10 to about 70, preferably
about 20 to about 60 grams of promoter (e.g. KOAc) per liter of catalyst.
 In one application, a layered catalytic composite is used to produce vinyl acetate from
the reaction of ethylene with acetic acid and oxygen. In this particular case, the inner core
preferably comprises cordierite and the refractory oxide layer is a zirconia layer having fibers
such as mullite, Superwool or TiO2. The layered composition has dispersed thereon palladium,
gold and potassium with rhodium being optional. A preferred method of dispersing the metals
onto the support is to first impregnate the layered support with an aqueous solution comprising a
palladium compound such as Pd(NH3)4 (OH)2 and then calcining the impregnated layered
composition. Next the calcined composition is impregnated with a solution comprising a gold
compound such as KAuO2, drying, calcining, and finally reducing the catalyst at a temperature
from ambient to about 550°C for a time of about 1 to about 5 hours. Reduction is carried out
under hydrogen or other reducing atmospheres. Addition of a promoter may be carried out
before or after the reduction step.
 The layered composition of the invention with catalytic metals thereon can also be
used for other hydrocarbon conversion processes such as hydrocracking, cracking, isomerization,
hydrogenation, dehydrogenation, oxidation and alkylation of both aromatic and isoparaffin
hydrocarbons. The desirable catalytic metals for these reactions are the platinum group metals,
as described above. Promoter metals selected from the group consisting of Sn, Ge, Re, Ga, Bi,
Pb, In, Ce, Zn and mixtures thereof can also be present as well as modifier metals selected from
the group consisting of alkali metals, alkaline earth metals and mixtures thereof can also de
dispersed on the layered support. Methods of dispersing these various components onto the
layered support are as set forth above. As described in US 6,280,608 B1 and incorporated herein
by reference in its entirety, a halogen component can also be present on the layered catalytic
 Although in the above embodiments all three metals are uniformly dispersed in the
outer layer of refractory oxide and substantially present only in the outer layer, it is also within the
bounds of this invention that the modifier metal can be present both in the outer layer and the inner
core. This is owing to the fact that the modifier metal can migrate to the inner core, when the core
is other than a metallic core.
 Although the concentration of each metal component can vary substantially, it is
desirable that the platinum group metal be present in a concentration of about 0.01 to about 5
weight percent on an elemental basis of the entire weight of the catalytic composition and
preferably from about 0.05 to about 2.0 wt.%. The promoter metal is present in an amount from
about 0.05 to about 10 wt.% of the entire catalytic composition while the modifier metal is present
in an amount from about 0.1 to about 5 wt.% and preferably from about 2 to about 4 wt.% of the
entire catalytic composition.
 The conditions necessary to carry out alkylation of aromatic compounds are well known
and are disclosed, for example, in US 3,965,043 and US 3,979,331 which are incorporated by
reference. Generally the process can be carried out in a batch type or a continuous type operation.
In a batch type process, the catalyst, aromatic compound and alkylating agent are placed in an
autoclave and the pressure increased, if necessary, in order to effect the reaction in the liquid phase.
An excess amount of aromatic compound should be present, preferably in a range of about 2:1 to
about 20:1 moles of aromatic compound per mole of alkylating agent. The reaction is carried out at
an elevated temperature since the rate of alkylation is undesirably low at room temperature.
Preferably the temperature is in the range of about 40°C to about 200°C. The process is carried out
for a time of about 0.5 to about 4 hours, after which the product is separated from the starting
materials by conventional means.
 If it is desired to carry out the process in a continuous manner, the catalyst is placed in a
reactor which is heated to the desired operating temperature and the pressure increased above
atmospheric, if necessary. The aromatic compound and alkylating agent are flowed over the
catalyst bed at a predetermined liquid hourly space velocity sufficient to effect alkylation. The
effluent is continuously withdrawn and conventional separation means used to isolate the desired
 Hydrocracking conditions typically include a temperature in the range of 240°C to
649°C (400°F - 1200°F), preferably between about 316°C and about 510°C (600-950°F). Reaction
pressures are in the range of atmospheric to about 24,132 kPag (3,500 psig), preferably between
about 1,379 and 20,685 kPag (200 - 3,000 psig). Contact times usually correspond to liquid hourly
space velocities (LHSV) in the range of about 0.1 hr-1 to 15 hr-1, preferably between about 0.2 and 3
hr-1. Hydrogen circulation rates are in the range of about 178 to 8,888 standard cubic meters per
cubic meter of charge (1,000 to 50,000 standard cubic feet (scf) per barrel of charge) preferably
between about 355 to about 5,333 std. m3/m3 (2,000 and 30,000 scf per barrel of charge).
 The reaction zone effluent is normally removed from the catalyst bed, subjected to
partial condensation and vapor-liquid separation and then fractionated to recover the various
components thereof. The hydrogen and, if desired some or all of the unconverted heavier materials,
are recycled to the reactor. Alternatively, a two-stage flow may be employed with the unconverted
material being passed into a second reactor. Catalysts of the subject invention may be used in just
one stage of such a process or may be used in both reactor stages.
 Catalytic cracking processes are preferably carried out with the catalyst composition
using feedstocks such as gas oils, heavy naphthas, deasphalted crude oil residua, etc. with gasoline
being the principal desired product. Temperature conditions of about 454°C to about 593°C (850°
to 1100°F,) LHSV values of 0.5 to 10 hr"1 and pressure conditions of from about 0 to about 345
kPag (50 psig) are suitable.
 Isomerization reactions are carried out in a temperature range of about 371 °C to about
538°C (700 - 1000°F). Olefins are preferably isomerized at temperatures of about 260°C to about
482°C (500°F to 900°F), while paraffins, naphthenes and alkyl aromatics are isomerized at
temperatures of about 371°C to 538°C (700°F to 1000°F). Hydrogen pressures are in the range of
about 689 to about 3,445 kPag (100 to 500 psig). Contact times usually correspond to liquid hourly
space velocities (LHSV) in the range of about 0.1 hr-1 to 10 hr-1. Hydrogen to hydrocarbon molar
ratios in the range of 1 to 20, preferably between 4 and 12.
 In a dehydrogenation process, dehydrogenatable hydrocarbons are contacted with the
catalyst of the instant invention in a dehydrogenation zone maintained at dehydrogenation
conditions. This contacting can be accomplished in a fixed catalyst bed system, a moving catalyst
bed system, a fluidized bed system, etc., or in a batch-type operation. A fixed bed system is
preferred. In this fixed bed system the hydrocarbon feed stream is preheated to the desired reaction
temperature and then flowed into the dehydrogenation zone containing a fixed bed of the catalyst.
The dehydrogenation zone may itself comprise one or more separate reaction zones with heating
means there between to ensure that the desired reaction temperature can be maintained at the
entrance to each reaction zone. The hydrocarbon may be contacted with the catalyst bed in either
upward, downward or radial flow fashion. Radial flow of the hydrocarbon through the catalyst bed
is preferred. The hydrocarbon may be in the liquid phase, a mixed vapor-liquid phase or the vapor
phase when it contacts the catalyst. Preferably, it is in the vapor phase.
 Hydrocarbons which can be dehydrogenated include hydrocarbons with 2 to 30 or more
carbon atoms including paraffins, isoparaffins, alkylaromatics, naphthenes and olefins. A preferred
group of hydrocarbons is the group of normal paraffins with 2 to about 30 carbon atoms. Especially
preferred normal paraffins are those having 2 to 15 carbon atoms.
 Dehydrogenation conditions include a temperature of from about 400°C to about 900°C,
a pressure of from about 1 to about 1013 kPa and a liquid hourly space velocity (LHSV) of from
about 0.1 to about 100 hr-1. Generally for normal paraffins the lower the molecular weight the
higher the temperature required for comparable conversion. The pressure in the dehydrogenation
zone is maintained as low as practicable, consistent with equipment limitations, to maximize the
chemical equilibrium advantages.
 The effluent stream from the dehydrogenation zone generally will contain unconverted
dehydrogenatable hydrocarbons, hydrogen and the products of dehydrogenation reactions. This
effluent stream is typically cooled and passed to a hydrogen separation zone to separate a hydrogen-
rich vapor phase from a hydrocarbon-rich liquid phase. Generally, the hydrocarbon-rich liquid
phase is further separated by means of either a suitable selective adsorbent, a selective solvent, a
selective reaction or reactions or by means of a suitable fractionation scheme. Unconverted
dehydrogenatable hydrocarbons are recovered and may be recycled to the dehydrogenation zone.
Products of the dehydrogenation reactions are recovered as final products or as intermediate
products in the preparation of other compounds.
 The dehydrogenatable hydrocarbons may be admixed with a diluent material before,
while or after being flowed to the dehydrogenation zone. The diluent material may be hydrogen,
steam, methane, ethane, carbon dioxide, nitrogen, argon and the like or a mixture thereof.
Hydrogen is the preferred diluent. Ordinarily, when hydrogen is utilized as the diluent it is utilized
in amounts sufficient to ensure a hydrogen to hydrocarbon mole ratio of about 0.1:1 to about 40:1,
with best results being obtained when the mole ratio range is about 1:1 to about 10:1. The diluent
hydrogen stream passed to the dehydrogenation zone will typically be recycled hydrogen separated
from the effluent from the dehydrogenation zone in the hydrogen separation zone.
 Water or a material which decomposes at dehydrogenation conditions to form water
such as an alcohol, aldehyde, ether or ketone, for example, may be added to the dehydrogenation
zone, either continuously or intermittently, in an amount to provide, calculated on the basis of
equivalent water, about 1 to about 20,000 weight ppm of the hydrocarbon feed stream. About 1 to
about 10,000 weight ppm or water addition gives best results when dehydrogenating paraffins
having from 2 to 30 or more carbon atoms.
 Hydrogenation processes including selective hydrogenation of dienes and trienes can be
carried out using reactors and hydrogenation zones similar to the dehydrogenation process
described above. Specifically, hydrogenation conditions include pressures of about 0 kPag to about
13,789 kPag, temperatures of about 30°C to about 280°C, H2 to hydrogenatable hydrocarbon mole
ratios of about 5:1 to about 0.1:1 and LHSV of about 0.1 to about 20 hr-1.
 The layered catalysts of this invention can also be used in oxidation reactions. These
oxidation reactions include:
1) partial oxidation of hydrocarbon streams, such as naphtha or methane, to generate
synthesis gas (CO +H2);
2) selective oxidation of hydrogen produced from endothermic dehydrogenation
reactions such as ethylbenzene to styrene; and,
3) oxidation of methane, ethane or carbon monoxide to clean up flue gas emissions from
 The layered sphere catalyst will be of most benefit to processes where the activity or
selectivity of the catalyst is limited by intraparticle diffusional resistance of product or reactants.
 The conditions for the oxidation process depend on the individual process application
but are generally about 350°C to about 800°C, about 40 kPa to about 2030 kPa, with a diluent
present in the feedstream such as N2, CO2, HO to control the reaction. Hydrogen may also be
present as a diluent and also a reactant. For the selective oxidation of hydrogen, the molar ratio of
oxygen to H2 may vary from about 0.05 to about 0.5. The diluent level is generally from about 0.1
to about 10 moles of diluent per mole of hydrocarbon. For example, the steam to ethylbenzene
molar ratio may be from about 5:1 to about 7:1 during the dehydrogenation of ethylbenzene.
Typical space velocity for oxidation is between about 0.5 to about 50 hr-1 LHSV.
 The following examples are presented in illustration of this invention and are not
intended as undue limitations on the generally broad scope of the invention as set out in the
 A slurry was prepared by adding to a vessel 634.2g of deionized water, 110g of 15%
of poly-vinyl alcohol (PVA) solution and 11.lg of acetic acid. The subsequent mixture was
stirred and to it there were added 221.8g of zirconia powder followed by 272.8g of zirconia sol
binder. The resultant mixture was milled for 8 hours.
 This resultant slurry was used to spray 700g of 7 mm diameter cordierite spheres
using a coating apparatus to give a layer having an average thickness of 200 micrometer. The
coated spheres were unloaded from the coating chamber and heated in air up to 600°C where they
were calcined for 4 hours under dry air. The calcined spheres were tested for attrition resistance
by taking 50cc of the calcined spheres, placing them in a flat drum and rotating the drum at
25rpm for 10 minutes. The impact breakage (IB) was determined as the weight percent fines
generated versus the total weight of the spheres. The IB for this sample was found to be 17.5 wt.
 Into a container there were added 1,021.6g of deionized water, 205.9g of a 15% PVA
solution and 21.2g of acetic acid. The mixture was stirred and to it there were added 27.3g of
mullite fibers comprising 80% Al2O3, 20% SiO2 with an average fiber length of about 200
micrometers and an average diameter of about 3 micrometers. Next, 426.2g of zirconia powder
was added followed by 469.8g of zirconia sol binder. The mixture was then ballmilled for about
 The resultant slurry from above was sprayed onto 711 g of 7mm diameter cordierite
spheres using a slurry coating apparatus to obtain wet spheres having an outer layer of about 200
micrometers thick. The wet spheres were heated in air to 600°C and calcined at 600°C for 4
hours under dry air. The calcined spheres were tested for impact breakage and were found to
have an 1B of 3.3 wt.%.
 A slurry was formed by adding l,121.7g of deionized water and 225.5g of a 15%
PVA solution and 23.2g of acetic acid into a vessel. The resultant mixture was stirred and to it
there were added 29.9g of mullite fibers as described in Example 2 followed by the addition of
463.9g of zirconia powder and then 514.5g of zirconia sol binder. The resultant slurry was
ballmilled for 6 hours.
 The resultant slurry was used to deposit a layer onto 800g of 7mm diameter cordierite
spheres using a slurry coating apparatus thereby producing wet spheres having a layer with an
average thickness of about 100 micrometers. The wet spheres were calcined at 600°C for 4 hours
under dry air and were found to have an IB of 3.0 wt.%.
 Into a mixing vessel there were added 602.8g of deionized water, 122.5g of a 15%
PVA solution and 12.6g of acetic acid. The mixture was stirred and to it there were added 15.3g
of titania fibers having an average length of about 3 micrometers and an average diameter of
about 0.3 micrometers. Next 253.7g of zirconia powder were added followed by 279.6g of
zirconia sol binder. The resulting slurry was ballmilled for 6 hours.
 The slurry described above was used to deposit a layer onto 730g of 7mm diameter
cordierite spheres by spraying the slurry onto the spheres using a slurry coating apparatus to give
wet spheres having an outer layer of with an average thickness of 200 micrometers. The wet
spheres were calcined at 600°C under dry air for 4 hours. The calcined spheres were tested and
were found to have an IB of 2.0 wt.%.
 Into a mixing vessel there were added 622.lg of deionized water, 129g of 15% PVA
solution and 13. lg of acetic acid. The mixture was stirred and to it there were added 35.8g of
titania fibers as described in Example 4 followed by the addition of 263.8g of zirconia powder
and finally 310.4g of zirconia sol binder. The resultant slurry was ballmilled for about 6 hours.
The slurry contained approximately 10 wt.% titania fibers.
 A portion of the slurry was deposited onto 730g of 7mm diameter cordierite spheres
using a slurry coating system to give a layer having an average thickness of about 200
micrometers. The wet spheres were calcined at 600°C for 4 hours under dry air and were found
to have an IB of 1.4 wt. %.
 It will be further appreciated that functions or structures of a plurality of components
or steps may be combined into a single component or step, or the functions or structures of one-
step or component may be split among plural steps or components. The present invention
contemplates all of these combinations. Unless stated otherwise, amounts, dimensions and
geometries of the various components depicted herein are not intended to be restrictive of the
invention, and other amounts, dimensions or geometries are possible. It will also be appreciated
from the above that the fabrication of the unique catalysts herein and the use thereof also
constitute methods in accordance with the present invention. The present invention also
encompasses intermediate (e.g. pre-catalysts) and end products resulting from the practice of the
methods herein. The use of "comprising", "having", "containing" or "including" also
contemplates embodiments that "consist essentially of or "consist of the recited feature.
 The explanations and examples presented herein are intended to acquaint others
skilled in the art with the invention, its principles, and its practical application. Those skilled in
the art may adapt and apply the invention in its numerous forms, as may be best suited to the
requirements of a particular use. Accordingly, the specific embodiments of the present invention
as set forth are not intended as being exhaustive or limiting of the invention. The scope of the
invention should, therefore, be determined not with reference to the above description, but should
instead be determined with reference to the appended claims, along with the full scope of
equivalents to which such claims are entitled. The disclosures of all articles and references,
including patents, patent applications and publications, are incorporated by reference for all
1. A layered composition for catalyzing production alkenyl alkanoates, comprising:
an inner core; and
an outer layer comprising a refractory inorganic oxide, a fibrous component, an
inorganic binder; and palladium and gold as catalytic components dispersed on the
outer layer, characterized in that the inorganic oxide birder is derived from an
inorganic binder precursor, wherein the inorganic binder precursor may decompose
to form the same oxide as the refractory inorganic oxide.
2. The composition as claimed in claim 1 where the fibrous component comprises
inorganic fibers, organic fibers or combinations thereof.
3. The composition as claimed in claim 2 where the inorganic fibers comprise mullite,
titania, potassium titanate, alumina, zirconia, silica, silicon carbide, cordierite, glass
or combinations thereof.
4. The composition as claimed in claim 2 where the organic fibers comprise graphite,
carbon, polymers or combinations thereof.
5. The composition as claimed in claim 1 where the inner core comprises alpha
alumina, theta alumina, silicon carbide, metals, montmorillonite, cordierite, gamma
alumina or combinations thereof.
6. The composition as claimed in claim 1 where the outer refractory inorganic oxide
comprises gamma alumina, delta alumina, eta alumina, theta alumina,
silica/alumina, zeolites, nonzeolitic molecular sieves, titania, zirconia, niobia or
7. The composition as claimed in claim 1 where the inorganic binder comprises
alumina, silica, zirconia, titania, aluminum phosphate or combinations thereof.
8. The composition as claimed in claim 1 where the layered composition has an impact
breakage of less than 10 wt. %, wherein the impact breakage equals weight of fines
divided by total weight of layered composition multiplied by 100%.
9. The composition as claimed in claim 8 where the layered composition has an impact
breakage of less than 5 wt. %, wherein the impact breakage equals weight of fines
divided by total weight of layered composition multiplied by 100%.
10.The composition as claimed in claim 9 where the layered composition has an impact
breakage of less than 3 wt. %, wherein the impact breakage equals weight of fines
divided by total weight of layered composition multiplied by 100%.
11.The composition as claimed in claim 1 further comprising a promoter component
dispersed on the outer layer, where the promoter component comprises an alkali
12.The composition as claimed in claim 1 further comprising an organic bonding agent.
13.The composition as claimed in claim 12 where the organic bonding agent comprises
polyvinyl alcohol (PVA), hydroxyl propyl cellulose, methyl cellulose, carboxy
methylcellulose or combinations thereof.
14.The composition as claimed in claim 1 where the outer layer has deposited thereon
from one to 5 additional layers and where adjacent layers comprise different
15.The composition as claimed in claim 1 where the inner core has a lower capacity for
catalytic components relative to the outer layer.
16.A method as claimed in producing alkenyl alkanoates, comprising:
contacting a feed comprising an alkene, an alkanoic acid and an oxygen containing
gas to a catalyst comprising a layered composition comprising:
an inner core; and
an outer layer comprising a refractory inorganic oxide, a fibrous component, an
inorganic binder, and palladium and gold as catalytic components dispersed on the
outer layer, wherein the inorganic oxide binder is derived from an inorganic binder
precursor, and the inorganic binder precursor may decompose to form the same
oxide as the refractory inorganic oxide.
17.The method as claimed in claim 16 where the catalyst comprises between 1 to 10
grams of palladium, and 0.5 to 10 grams of gold per liter of catalyst, with the
amount of gold being from 10 to 125 wt % based on the weight of palladium.
18.The method as claimed in claim 17 where the catalyst further comprises a potassium
containing promoter component dispersed on the outer layer in an amount between
10 and 70 grams per liter of catalyst.
19.The method as claimed in claim 18 where the inner core comprises cordierite.
20.The method as claimed in claim 19 where the outer layer comprises zirconia.
21. A method for preparing a catalyst for alkenyl alkanoate production, comprising:
coating an inner core with a slurry comprising an outer refractory inorganic oxide,
an inorganic binder precursor, a fibrous component, an organic bonding agent and a
solvent to give a coated core with an outer layer; and
calcining the coated core at a temperature of at least 200°C for a time sufficient to
bond the outer layer to the inner core to provide a layered composition;
where the layered composition comprises at least one catalytic component
comprising palladium and gold.
22.The method as claimed in claim 21 further comprising:
impregnating the outer layer with a solution comprising palladium, gold or
combinations thereof to provide an impregnated outer layer; and
calcining the outer layer.
23.The method as claimed in claim 22 where the impregnating step is a co-
impregnation of one or more of palladium, or gold.
24.The method as claimed in claim 22 where the impregnating step is a sequential
impregnation of one or more of palladium, or gold.
25.The method as claimed in claim 22 where the impregnating step comprises co-
impregnating with a solution comprising palladium and followed by impregnating
with a solution comprising gold.
26.The method as claimed in claim 22 further comprising:
impregnating the outer layer with a solution comprising palladium;
calcining the outer layer; and
impregnating the outer layer with a solution comprising gold.
27.The method as claimed in claim 21 wherein the slurry comprises a refractory
inorganic oxide comprising palladium, gold or combinations thereof.
A layered composition for catalyzing production alkenyl alkanoates, comprising: an inner
core; and an outer layer comprising a refractory inorganic oxide, a fibrous component, an
inorganic binder; and palladium and gold as catalytic components dispersed on the outer
layer, characterized in that the inorganic oxide binder is derived from an inorganic binder
precursor, wherein the inorganic binder precursor may decompose to form the same oxide
as the refractory inorganic oxide.
|Indian Patent Application Number||1638/KOLNP/2007|
|PG Journal Number||06/2011|
|Date of Filing||08-May-2007|
|Name of Patentee||CELANESE INTERNATIONAL CORPORATION|
|Applicant Address||1601 WEST LBJ FREEWAY DALLAS, TX|
|PCT International Classification Number||B01J 23/44|
|PCT International Application Number||PCT/US2006/012064|
|PCT International Filing date||2006-03-30|