Title of Invention

A PROCESS FOR THE PREPARATION OF INTERCALATED CLAY COMPOSITES USEFUL AS SOLID ACID CATALYSTS.

Abstract The present invention relates to a process for the preparation of metal ion exchanged clay composites useful as solid acid catalysts. The novel catalyst containins metal cations supported on acid treated layered clay (Montmorillonite) for Friedel Crafts (F.C.) reaction. The intercalated clay composites are prepared by exchanging suitable metal cations with protons and other exchangeable cations in the interlamellar spacing of expandable acid treated layered aluminosilicates (like Montmorillonite clay mineral of smectite group clays). These composites are useful as solid Bronsted and Lewis acid catalysts for organic synthesis.
Full Text The present invention relates to a process for the preparation of metal ion exchanged clay composites useful as solid acid catalysts.
This invention is more particularly related to a novel catalyst containing metal cations supported on acid treated layered clay (Montmorillonite) for Friedel Crafts (F.C.) reaction.
The present invention particularly provides an improved process for the preparation of intercalated clay composites by exchanging suitable metal cations with protons and other exchangeable cations in the interlamellar spacing of expandable acid treated layered aluminosilicates (like Montmorillonite clay mineral of smectite group clays). These composites are useful as solid Bronsted and Lewis acid catalysts for organic synthesis.
Different types of modified supported inorganic reagents are rapidly emerging as a new and environment friendly materials. Attempts are being made to replace highly corrosive HF in olefm alkylation, anhydrous AlClj in F.C. alkylation etc. by supported solid acid catalysts. All the solid acids are characterized by the presence of protons or coordinatively unsaturated cationic centers on the surface leading to Bronsted and Lewis acidity. Acid treated clays are partially delaminated and exhibit higher surface area than the parent clays. Initially protons occupy exchanged sites in acid treated clays and then unstable H+forms of the clays are converted into predominantly A13+ forms due to significant dissolution of aluminium from the octahedral lattice layers. These highly acidic forms of smectite clays have been described as broad spectrum catalysts for organic synthesis.
Replacement of environmentally unacceptable anhydrous AlCh, an established catalyst for F.C. alkylation by supported AlCb on Montmorillonite K10 (i.e. acid treated

Montmorillonite having no layer structure ) has been claimed to be an efficient catalyst [J.H.Clark, K.M.Andrew, A.J.Teasdale and S.J.Barlow; J.Chem.Soc. Chem. Commun. (1995) 2037]. Such solid catalyst was prepared by refluxing a well stirred slurry of anhydrous AlC^, predried support i.e. Montmorillonite(Mont) K-10 (typically 300°C for 18 h) and benzene for 1 h under nitrogen to make an optimum loading as 0.75 mmol AlCb g"1 Mont K-10. .Anchoring of Aids on the hydroxy groups of the supporting materials may occur through the active group - O - AlCla [ R.S.Drago and E.E.Gatty; J. Am. Chem. Soc. 110 (1988) 3311] . Reference may be made to the patent J. P.Pat. 9255605 issued to I.Fukada et.al. where bisphenol was prepared by condensation of PhOH with acetone in presence of Mont. Mn+x/n(Al4-xMgx)Si8O2o(OH)4.yH2O(M = Metal, H; 0 1; y > 0) where interlayer cations have been exchanged with cations chosen from Al, Cr, Fe and Cu. Phenol was autoclaved with acetone in presence of Al -exchanged Mont, at 100 °C and 5 kg / cm2 pressure for 2 hours to give 6.3% bisphenol and 1.3% 2-(2/-hydroxyphenyl)-2-(4/-hydroxyphenyl)propane. Smectite clays have been shown to be very effective supports for a number of transition metal salts which may be used as F.C.alkylation catlysts [J.H.Clark, A.P.Kybett, D.J.Macquarrie, S.J.Barlow and P.Landon; J.Chem.Soc. Chem. Commun. (1989) 1353]. One such example is "Clayzic" (ZnCla -Montmorillonite K10 ) which exhibits both Bronsted and Lewis surface acidities [ J. Massam & D.R. Brown; Catalysis Letters 35 (1995) 335] and such solid catalyst was prepared by deposition of ZnCb on Montmorillonite K 10 by evaporation to dryness of 1 % suspension of K 10 in methanol solution of ZnCU at a concentration equivalent to loading of 1.0 mmol ZnCl2 g"1 Mont K-10. Good conversion rates are also achieved in F.C alkylation by using transition metal exchanged Montmorillonite K 10 [P. Laszlo and

A. Mathy; Helvetica Chimica Acta 70 (1987) 577]. U.Flessner (DE Pat. 19935914) discloses alkylation of phenol by olefins in presence acid activated Montmorillonite containing Fe3+ as the interlayer cations. The catalyst having a specific surface of 290 m2/g and pore volume 0.338 ml/g gives 38.7% product at 90°C in 3 hours. The US Pat. 6180557 issued to Choudhary et.al. wherein preparations of solid catalyst of metal oxide or halide on different types of supports useful for heterogeneously catalysed F. C. reactions such as alkylation were disclosed. Such solid catalysts are mixed oxides or halides of Ga, Al, Fe, Zn, In, Tl etc. on porous support like SZ5564 (a product of NORTON Co USA; chemical composition 94.1 % (ZrO2 + HfO2), 3.5 % CaO, 1.6 % Si02 and 0.41 % A12O3, Surface area 0.1 m2/g, Porosity 45 %) or Montmorillonite K 10 (a product of Aldrich Chemical Co USA). The ZnTlO-SZ5564 supported catalysts was prepared by impregnating a mixture of 0.1 g zinc acetate and 5.0 g thallous acetate, dissolved in 14 ml distilled water, on 20 g fine particles (>100 mesh) of SZ5564 catalyst support by incipient wetness technique (in incipient wetness technique, the volume of impregnation solution is just sufficient to completely wet the solid to be impregnated and there is no free solution in the impregnation mixture), drying the impregnated mass in an air oven at 110 °C for 10 h and calcining in air at 550°C for 4 h. The surface area of the catalyst was 0.22 m2/g . Again, the preparation of FeTlCl-Montmorillonite K 10 was done by impregnating a mixture 0.9 g ferric chloride and 0.1 g thallic-fhloride, dissolved in 18 ml moisture free acetonitrile, on 10 g Montmorillonite K 10 clay by incipient technique, drying the impregnated mass under vacuum at 40 °C for 20 h and then calcining or heating further in a flow of nitrogen free from oxygen and traces of moisture at 120°CforlOh.

The main object of the present invention is to provide a process for the preparation of metal ion exchanged clay composites useful as solid acid catalysts.
Another object of the present invention is to provide a simple process of preparing solid acid catalysts with Bronsted and Lewis acid sites for organic synthesis.
Accordingly, the present invention provides a process for the preparation of metal ion exchanged clay composites useful as solid acid catalysts which comprises
refluxing treating with metal chloride (MC12) solution where M = Zn,£Cd etc. for a period of about 12 hours followed by dialysis to obtain a pure electrolyte free metal cations Mn+-
exchanged acid treated Montmorillonite [ Mn+ - Montmorillonite (AT)] composites, (iii)
o "f° drying the above said composite at a temperature ranging 50 ± 5 C /.obtain the solid
be)nscw products, activating the dried material at a temperature ranging/100 - 200°C for a period
of 1-6 hours.
In an embodiment of the present invention, the oxide composition of Montmorillonite clay collected from Crook County, Wyonimg, USA (SWy - 2) after purification is as follows - SiO2: 58.12; A12O3: 18.93; Fe2O3 : 4.63; MgO : 2.52; CaO : 1.12; LOI: 13.54 and others(alkali metal oxides) 1.14%.
The different process steps of the present invention are given below:The present invention is distinguished from the prior arts in that the metal ion exchanged acid treated Montmorillonite composites are prepared by acid treatment of The novelty of such solid acid catalysts lies in that the active acid sites i.e. protons and metal cations are mostly present in the interlamellar spacing of the clay which have the potentiality for shape or size selectivity in organic synthesis.
The main object of the present invention is to provide a simple process of
preparing solid acid catalysts with Bronsted and Lewis acid sites for organic synthesis.
Accordingly, the present invention provides a process for the preparation of intercalated clay composites useful as solid acid catalysts which comprises; i) characterized in that treating
activated at 100 - 200oC before using as solid catalyst in the synthesis of Friedel crafts reaction.
In an embodiment of the present invention, the oxide composition of Montmorillonite clay collected from Crook County, Wyonimg, USA (SWy - 2) after purification is as follows - SiO2 : 58.12; A12O3: 18.93; Fe2O3 : 4.63; MgO : 2.52; CaO : 1.12; LOI: 13.54 and others(alkali metal oxides) 1.14%.
The different process steps of the present invention are given below:
Purification of the clay (Montmorillonite):
About 50 g of the Montmorillonite clay was suspended in 1000 ml distilled water by stirring for half an hour and was set aside for about 24 hours. The suspension upto 10 cm height from the top of the surface of the suspending liquid was collected for Conversion into Na +- Montmorillonite:
About 2 g of dry purified clay was suspended into 100 ml of distilled water and to it 100 ml of 2 M NaCl solution was added and kept stirring for about 12 hours. The mass was allowed to settle and the supernatant liquid was decanted off. The slurry was again treated with 2 M NaCl solution and stirred. This step was repeated for about four times. The excess NaCl was removed by dialysing the residue against distilled water till the conductivity of dialyzate approached that of distilled water and showed negative test for chloride ion with silver nitrate. The mass was then dried at 50 ± 5°C in air oven.
Acid treatment of Montmorillonite;
3.0 g of dry XRD evaluation;
Oriented films for the study were prepared from H+- Montmorillonite, Zn2+-Montmorillonite(AT), Cd2+- Mont-morillonite (AT) on glass slides by allowing a few drops of suspension of the clay in water to dry at room temperature. The basal spacings (dooi) at room temperature as determined by XRD technique were found to be about 12.4, 14.7, 15.6 A for H+-Montmorillonite, Zn2+- Montmorillo-nite (AT), Cd2+-Montmorillonite (AT) respectively. The basal spacings of the layered solid acid composites reflect the interlayer spacing available for carrying out the organic synthesis particularly in respect of shape and size selectivity.
Cation Exchange Capacity (CEO;
CEC of Na+ -Montmorillonite as well as acid treated Montmorillonite was determined by stirring 0.5 g of the dry clay with 10 ml 0.5 M alcoholic solution

(stock solution) for 24 hours so that all the interlayer cations were exchanged with Ca2+. Then the slurry was filtered and washed the residue with alcohol and hot water till the washings were Cl" free. The washings were collected along with the filtrate and Ca2+ was estimated in this solution. Difference of amount of Ca2+ in the stock solution and in the filtrate gave the amount of Ca2+ exchanged. From these exchange data the CECs of Na+ -Montmorillonite and H*- Montrnorillonite were found to be 80 and 35 meq / lOOg clay respectively. The decrease of CEC value in acid treated Montmorillonite signifies the leaching of aluminium from octahedral sites with increase in porosity of the matrix beneficial for solid acid catalysis.
The following examples are given by way of illustration of the present invention and should not be construed to limit the scope of the invention.
Example 1:
1.0 g of dried H+ - Montmorillonite clay was dispersed in 100 ml of distilled water by stirring for about 3 hours. To this homogeneous suspension, 100 ml of 2 M ZnCla solution was added and stirred for about 12 hours. The mass was allowed to settle and the supernatant liquid was decanted off. The slurry is again treated with another 100 ml of 2 M ZnC\2 solution and whole process was repeated. Then this settled mass was dialysed against distilled water till the conductivity of dialyzate approached that of distilled water and showed negative test for chloride ion with silver nitrate. The mass which contained Zn2*- Montmorillonite (AT) was then dried at 50 ± 5°C in air oven. The dried mass was then activated at about 150°C for a period of 3 hours before using as solid acid catlyst in organic synthesis like F.C.reaction for alkylation.

Example 2:
1.0 g of dried H* - Montmorillonite clay was dispersed in 100 ml of distilled water by stirring for about 3 hours. To this homogeneous suspension, 100 ml of 2 M CdCb solution was added and stirred for about 12 hours. The mass was allowed to settle and the supernatant liquid was decanted off. The slurry is again treated with another 100 ml of 2 M CdCh solution and whole process was repeated. Then this settled mass was dialyzed against distilled water till the conductivity of dialyzate approached that of distilled water and showed negative test for chloride ion with silver nitrate. The mass which contained Cd2+- Montmorillonite (AT) was then dried at 50 ± 5°C in air oven. The dried mass was then activated at about 150 °C for a period of 3 hours before using as solid acid catlyst in organic synthesis like F.C.reaction for alkylation.
ExampleS:
0.3 g ( 0.105 mmol) H+ - Montmorillonite composite heated at 150°C in an air oven for about 3 hours and cooled in a desiccator to room temperature and then added to mixture of 8 ml benzene (dry) and 0.24 ml benzyl chloride (dry) in a round bottom flask fitted with moisture arresting guard tube and stirring arrangement. The reaction was allowed to continue at room temperature for a period of 24 hours. 31.1% of benzyl chloride was converted to the major product diphenylmethane as analysed by Gas Liquid Chromatography.

Example 4:
0.6 g (0.105 mmol) Cd2+-Montmorillonite (AT) composite heated at 150°C in an air oven for about 3 hours and cooled in a desiccator to room temperature and then added to mixture of 8 ml benzene (dry) and 0.24 ml benzyl chloride (dry) in a round bottom flask fitted with moisture arresting guard tube and stirring arrangement. The reaction was allowed to continue at room temperature for a period of 24 hours. 46.7% of benzyl chloride was converted to the major product diphenylmethane as analysed by Gas Liquid Chromatography.
Example 5:
0.6 g (0.105 mmol) Zn2+- Montmorillonite (AT) composite heated at 150°C in an air oven for about 3 hours and cooled in a desiccator to room temperature and then added to mixture of 8 ml benzene (dry) and 0.24 ml benzyl chloride (dry) in a round bottom flask fitted with moisture arresting guard tube and stirring arrangement. The reaction was allowed to continue at room temperature for a period of 24 hours. 99.9% of benzyl chloride was converted to the major product diphenylmethane as analysed by Gas Liquid Chromatography.
Example 6:
0.6 g ( 0.105 mmol) Zn2+ - Montmorillonite (AT) composite heated at 150°C in an air oven for about 3 hours and cooled in a desiccator to room temperature and then added to mixture of 40ml benzene (dry) and 1.21 rnl benzyl chloride (dry) in a round bottom

flask fitted with moisture arresting guard tube and stirring arrangement. The reaction was allowed to continue at room temperature for a period of 24 hours. 92.2% of benzyl chloride was converted to the major product diphenylmethane as analysed by Gas Liquid Chromatography.
The main advantages of the present invention are :
1. The metal ion exchanged acid treated clay composites could maintain interlamellar
spacing in the range 5 - 6 A at room temperature and hence may be used as size/shape
selective solid acid catalysts.
2. These composites exhibit layered structure up to about 200°C.
3. These composites can be prepared by a simple method and activation temperature of
the catalysts could preferably be maintained at around 150°C for about 3 hours.





We Claim:
(1) A process for the preparation of intercalated clay composites useful as solid acid catalysts which comprises; i) characterized in that treating (2) A process as claimed in 1, wherein metal ions in the acid treated Montmorillonite clay composites are any active metal from transition metal groups.
(3) A process for the preparation of intercalated clay composites useful as solid acid catalysts substantially as herein described with reference to the examples.

Documents:

398-DEL-2002-Abstract-(11-08-2010).pdf

398-del-2002-abstract.pdf

398-DEL-2002-Claims-(11-08-2010).pdf

398-del-2002-claims.pdf

398-DEL-2002-Correspondence-Others-(11-08-2010).pdf

398-del-2002-correspondence-others.pdf

398-del-2002-correspondence-po.pdf

398-DEL-2002-Description (Complete)-(11-08-2010).pdf

398-del-2002-description (complete).pdf

398-del-2002-form-1.pdf

398-del-2002-form-18.pdf

398-del-2002-form-2.pdf

398-DEL-2002-Form-3-(11-08-2010).pdf

398-del-2002-form-3.pdf


Patent Number 243747
Indian Patent Application Number 398/DEL/2002
PG Journal Number 45/2010
Publication Date 05-Nov-2010
Grant Date 03-Nov-2010
Date of Filing 28-Mar-2002
Name of Patentee COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110001, INDIA
Inventors:
# Inventor's Name Inventor's Address
1 DIPAK KUMAR DUTTA REGIONAL RESEARCH LABORATORY, JORHAT-785006, ASSAM, INDIA.
2 MADAN GOPAL PATHAK REGIONAL RESEARCH LABORATORY, JORHAT-785006, ASSAM, INDIA.
3 OMAR SAADUDDIN AHMED REGIONAL RESEARCH LABORATORY, JORHAT-785006, ASSAM, INDIA.
PCT International Classification Number C07C 1/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA