Title of Invention

"A PROCESS FOR THE PREPARATION OF A NOVEL CATALYST USEFUL FOR CONDENSATION REACTIONS"

Abstract The Present invention relates to a process for preparation of novel catalyst useful for condensation reactions. The catalyst comprising oxides of copper, zinc, and alumina prepared through a novel deposition precipitation method using urea as hydrolyzing method. The desired ammonium hydroxide to hydrolyze the active metal component precursors was generated in situ. Thus, in this method the active copper and zinc metal hydroxides are precipitated together over a finely dispersed alumina support. This method thus results in the preparation of the active catalyst possessing high surface area, nano sized particles, homogeneous in structure, and uniform throughout bulk. The resulting catalysts exhibit high activity and selectivity for condensation reactions
Full Text The Present invention relates to a process for preparation of novel catalyst useful for condensation reactions.
The present invention particularly relates to a process for the preparation of a highly active and selective catalyst for the synthesis of quinolines. The catalyst prepared by the process of the present invention is useful for the preparation of quinoline from aniline and glycerol, and 2-methyl-8-ethylquinoline from 2-ethylaniline and ethylene glycol in vapour phase in high yields. Quinoline and substituted quinolines are an important class of heterocyclic compounds of high industrial interest. These compounds find many applications such as intermediates in the production of Pharmaceuticals, herbicides, fungicides, acid-binding agents and corrosion inhibitors.
As known from modern catalytic surface science that the nature and quality of the
catalytic carrier material is a key component of catalysis. Defined properties and consistent quality of the carrier material are pre-requisites for a successful catalyst. It is known that the nature and quality of a catalyst carrier material is an utmost important to the overall performance of the catalyst. The carrier influences the catalytic reaction and process by its chemical, physical and mechanical properties. There are several methods such as impregnation, precipitation, physical mixing, and chemical vapour deposition to incorporate the active metal component over the catalytic carrier. Most of these methods are suitable for incorporating a single active metal component over the catalyst carrier. To achieve better catalytic properties such as high activity, high selectivity, and long life it is necessary to incorporate more than one active metal component over the catalyst carrier. Therefore, a better catalyst system and preparation method was necessary to incorporate more than one active metal component to a catalyst carrier. As a result of extensive research we have devised a better method of deposition precipitation to make a novel catalyst system useful for condensation reactions such as the synthesis of quinolines. In this method the desired active metal components are co-precipitated together over a finely dispersed carrier material by in situ generated ammonium hydroxide. This method thus results in better catalyst systems having nanosized particles, high surface area, uniform throughout bulk, and good reproducibility.
Quinoline and substituted quinolines are very important chemical intermediates for the design of many synthetic anti-malarial compounds. Recently, Campanati et al
reported [Catalysis Letters, 47, 247 (1997)] the vapour phase synthesis of 2-methyl-8-ethylquinoline from ethylene glycol and 2-ethylaniline over a K 10-montmorillonite catalyst at 603 K with a 41 % yield of the desired product. The K 10-montmorillonite is a porous material, therefore, operation in vapour phase for longer times is arduous and no quick diffusion of the products formed on the surface is possible. In this patent we describe a better catalyst system for the synthesis of quinolines from aniline and glycerol, and 2-methyl-8-ethylquinoline from 2-ethylaniline and ethylene glycol by condensation followed by oxidative dehydrogenation.
The main objective of the present invention is to provide a process for the preparation of new catalysts useful for the condation reactions, which obviates the drawbacks of known catalysts such as clays, heteropoly acids and transition metal oxides.
f
Another object of the present invention is to provide a process for the preparation of highly active and selective catalyst useful for producing quinoline from aniline and glycerol, and 2-methyl-8-ethylquinoline from 2-ethylaniline and ethylene glycol in greater yields by vapour phase route, which overcomes the drawbacks of the hitherto known processes.
In view of the above, the present invention as a result of extensive research could overcome such disadvantages to bring out a catalyst comprising oxides of copper, zinc, and alumina prepared through a novel deposition precipitation method using urea as hydrolyzing method. The desired ammonium hydroxide to hydrolyze the active metal component precursors was generated in situ. Thus, in this method the active copper and zinc metal hydroxides are precipitated together over a finely dispersed alumina support. This method thus results in the preparation of the active catalyst possessing high surface area, nanosized particles, homogeneous in structure, and uniform throughout bulk. The resulting catalysts exhibit high activity and selectivity for condensation reactions. These novel catalysts additionally possess dehydration, dehydrogenation and hydrogenation functionality on its surface. Combining all these important properties together in a desired proportion on a single catalyst is an important achievement in the area of catalyst making.
The objective of the present invention is to provide a process for the preparation of a new catalyst comprising of copper oxide, zinc oxide and alumina by a deposition precipitation method.
Accordingly the present invention provides a process for the preparation of a novel catalyst useful for the condensation reactions which comprises: the co-precipitation of mixed oxides together with a support by a homogeneous deposition precipitation method and drying the obtained materials at a temperature of 383 to 403 K and calcining it at a temperature in the range of 673 to 973 K, optionally treating with promoter metal oxides / hydroxides followed by drying and calcination by conventional method to get novel catalyst.
In an embodiment of the present invention the support material used may be such as alumina, silica, titania, alumina-silica and mixtures thereof. In another embodiment of the present invention the active compound used may be in the range of 5-20 wt %.
In yet another embodiment of the present invention the composition of mixed oxide varies in the range of 1 to 5 mole %. In still another embodiment the calcination temperature of the precipitated catalyst may range from 673 to 973 K for 6 to 16 hr.
In further embodiment of the invention the promoter oxides / hydroxides used may be such as potassium, cobalt, cesium, silver and manganese. In yet another embodiment the active oxides used may be such as vanadium, molybdenum, and tungsten.
The process for the preparation of a new catalyst of the present invention is illustrated by the examples given below which should not however be considered to limit the scope of the invention.
EXAMPLE 1
The CuO-ZnO-Al2O3 catalyst (1:2.3:2.7 mole ratio) was prepared by a deposition precipitation method using urea as hydrolyzing agent. The required quantities of copper nitrate (10.02 g) and zinc nitrate (17.66 g) to yield the desired composition of the catalyst was dissolved in deionized water to which an excess amount of urea (246 g) was added. The alumina support (surface area 204 m2g-1, pore volume 0.65 cm3g-1, particle size less than 0.1 mm) in fine powder form (20 g) was added to this solution and heated to 368 K with vigorous stirring. Precipitation to neutral pH was complete in 8 hours. The precipitates thus obtained were filtered off; washed several times with deionized water,
dried at 383 K for 16 hours and calcined at 623 K. The finished catalyst had the specific surface area of 80 m2g-1. The X-ray powder diffraction pattern of the sample revealed that the material to be in an amorphous state. The catalyst was employed for the condensation of aniline and glycerol in vapour phase. The overall conversion of aniline was 72% and the quinoline yield was 56%.
EXAMPLE 2
The catalyst was obtained by impregnating Cr atoms on Zn oxide solid. To impregnate Cr, the chromium nitrate (15.98 g) was dissolved in water and to which oven dried zinc hydroxide catalyst sample was, added. The excess water was evaporated on a water bath. To make zinc hydroxide, zinc nitrate (60 g) and urea (300 g) were dissolved in distilled water and were heated to 368 K for 8 hours. The resulting precipitate was washed with distilled water until free from anions. The obtained catalyst sample was oven dried again and calcined at 773 K for 6 h. The resulting catalyst was employed for the condensation of aniline and glycerol in vapour phase. The overall conversion of aniline was 65% and the quinoline yield was 48%.
EXAMPLE 3
A SiO2 supported CuO-ZnO mixed oxide based catalyst was used. The SiO2 support material was separately prepared by hydrolysis of sodium silicate (50 g) with dilute ammonium hydroxide (0.1%). The obtained precipitate was washed thoroughly with deionized water until free from anion impurities and dried in oven for 24 hours at 398 K and calcined at 673 K for 8 hours. Zinc and copper oxides from their nitrate salts were impregnated on the support material and was subsequently dried at 393 K for 12 hours and finally calcined at 773 K for 6 hours. To impregnate zinc, zinc nitrate (17.7 g) was dissolved in doubly distilled water (120 ml) to which the finely powder silica support was added. The excess water was evaporated on a water bath and oven dried at 393 K for 8 h. To this oven dried sample the copper nitrate (10.5 g) dissolved in doubly distilled water (100 ml) was added and the excess water was evaporated on a water bath. The
resulting sample was once again oven dried at 393 K for 8 h and obtained sample was finally calcined in open-air furnace at 773 K for 6 h. The resulting catalyst was employed for the condensation reaction of 2-ethylaniline and ethylene glycol in vapour phase. The overall conversion of 2-ethylaniline was 74% and the 2-methyl-8-ethylquinoline yield was 55%.
EXAMPLE 4
Copper nitrate (20.04 g) and zinc nitrate (26.5 g) were dissolved separately in distilled water and mixed together to which an excess of urea (1:1.5 mole ratio) was added. To this solution the A12O3 (30 g) in fine powder form was added and heated to 368 K with vigorous stirring. Precipitation to neutral pH was complete in 8 hours. The

precipitates thus obtained were filtered off, washed several times with deionized water until free from anion impurities, dried at 383 K for 16 hours and calcined at 623 K. The resulting catalyst was employed for the condensation reaction of 2-ethylaniline and ethylene glycol in vapour phase. The overall conversion of 2-ethylaniline was 68% and the 2-methyl-8-ethylquinoline yield was 52%.
EXAMPLE 5
Copper nitrate (10 g) and zinc nitrate (17.7 g) were dissolved separately in distilled water and mixed together to which an excess of urea (1:1.5 mole ratio) was added. To this solution the A12O3 (20 g) in fine powder form was added and heated to 368 K with vigorous stirring. Precipitation to neutral pH was complete in 8 hours. The precipitates thus obtained were filtered off, washed several times with deionized water until free from anion impurities, dried at 383 K for 16 hours and calcined at 623 K. Potassium hydroxide (1.2 g) promoter was dissolved in doubly distilled water (50 ml) and to which the calcined sample was added. The excess water was evaporated and oven dried at 393 K for 8 h and calcined again at 773 K for 4 h. The resulting catalyst was employed for the condensation of aniline and glycerol in vapour phase. The overall conversion of aniline was 68% and the quinoline yield was 56%.
EXAMPLE 6
Ammonium metavanadate (6.5 g) and ammonium heptamolydate (8.2 g) were dissolved separately in distilled water and mixed together. To this solution the A12O3 (20 g) in fine powder form was added and heated on a water bath with vigorous stirring until all excess water was evaporated. The obtained sample was oven dried at 383 K for 16 hours and calcined at 773 K for 5 hours. The resulting catalyst was employed for the condensation of aniline and glycerol in vapour phase. The overall conversion of aniline was 69 % and the quinoline yield was 54 %.




We claim:
1. A process for the preparation of novel catalyst useful for the condensation reactions which comprises: the co-precipitation of mixed oxides together with a support by a homogeneous deposition precipitation method and drying the obtained materials at a temperature of 383 to 403 K and calcining it at a temperature in the range of 673 to 973 K, optionally treating with promoter metal oxides / hydroxides followed by drying and
calcination by conventional method to get novel catalyst.
2. A process as claimed in claim 1 wherein the support material is selected from alumina, silica, titania, alumina-silica and mixtures thereof.
3. A process as claimed in claims 1 and 2 wherein the amount of active mixed oxide component used ranges from 5 to 20 wt%.
4. A process as claimed in claims 1 to 3 wherein the calcination temperature of the mixed oxide catalyst ranges from 673 to 973 K for 6 to 16 hours.
5. A process as claimed in claims 1-5 wherein the promoter oxide / hydroxide is such as potassium, cobalt, cesium, silver and manganese.
6. A process as claimed in claims 1-6 wherein the active oxide component used is such as copper, vanadium, molybdenum, zinc, and tungsten.
7. A process for the preparation of a novel catalyst useful for condensation reactions substantially as herein described with reference to the examples.


Documents:

771-del-2000-abstract.pdf

771-del-2000-claims.pdf

771-del-2000-correspondence-others.pdf

771-del-2000-correspondence-po.pdf

771-del-2000-description (complete).pdf

771-del-2000-form-1.pdf

771-del-2000-form-19.pdf

771-del-2000-form-2.pdf


Patent Number 226261
Indian Patent Application Number 771/DEL/2000
PG Journal Number 01/2009
Publication Date 02-Jan-2009
Grant Date 16-Dec-2008
Date of Filing 29-Aug-2000
Name of Patentee COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110 001, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 BENJARAM MAHIPAL REDDY INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD - 500 007,ANDHRA PRADESH, INDIA.
2 IBRAM GANESH INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD - 500 007,ANDHRA PRADESH, INDIA.
3 BISWAJIT CHOWDHURY INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD - 500 007,ANDHRA PRADESH, INDIA.
4 VANGALA RANGA REDDY INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD - 500 007,ANDHRA PRADESH, INDIA.
PCT International Classification Number B01J 023/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA