Title of Invention	AN IMPROVED PROCESS FOR THE PREPARATION OF BENZONITRILE
Abstract	An improved process for the preparation of benzonitrile which comprises passing a feed consisting of toluene, ammonia in a molar ratio in the range of 1:1 to 1:20, water and air or oxygen gas in a feed ratio of 60 oc per minute of ammonia over a silico-alumino-phosphate (SAPO) catalyst, prepared by the process such as herein described at a temperature in the range of 300-450°C and weight hourly space velocity of liquid products in the range of 0.25 to 1.0 per hour to obtain benzonitrile.

Title of Invention

AN IMPROVED PROCESS FOR THE PREPARATION OF BENZONITRILE

Abstract

An improved process for the preparation of benzonitrile which comprises passing a feed consisting of toluene, ammonia in a molar ratio in the range of 1:1 to 1:20, water and air or oxygen gas in a feed ratio of 60 oc per minute of ammonia over a silico-alumino-phosphate (SAPO) catalyst, prepared by the process such as herein described at a temperature in the range of 300-450°C and weight hourly space velocity of liquid products in the range of 0.25 to 1.0 per hour to obtain benzonitrile.

Full Text	This invention relates to an improved process for the preparation of benzonitrile. The present invention particularly relates to an improved process for the preparation of benzonitrile. According to the process of the present invention, toluene is reacted with ammonia and air in the presence of crystalline, porous vanadium aluminophpsphates(VAPO) catalyst. The process of preparing the above catalyst has been described and claimed in our copending application number 1459/del/95. In the presently known process, benzonitrile can be produced from ammox-idation. The conventional catalysts have been amorphous in nature and not shape selective catalysts. These catalysts have been employed in mostly fixed bed reactors. The following patents have discussed the preparation of nitriles of present interest, e.g. Eur.Pat; Appl. EP 37173 (1981), US Patent 4876348 (1989),US Patent 4603 207 (1986), Eur. Pat 0037123A1 (1981), Brit. Patent 77746 (1957), Ger. (East) DDPatent 241903 (1985), US Patent 3981879 (1976), US Patent 2839535 (1958), US Patent 2510605 (1950) , US Patent 3981879 (1976) . In these inventions the yield of nitrile may or may not be highly selective. Particularly high-boiling products, CO,C02 were formed, due to the amorphous nature of the catalysts. The high-boiling products create environmental and disposal problems. The object of the present invention is to provide an improved process for the preparation of benzonitrile employing porous active catalytic materials. The other objective of the invention is to provide a process for the preparation of nitriles wherein the formation of CO, C02 and high-boiling products are minimized. The present invention provides >50% yield of benzonitrile from toluene ammoxidation in one step with very high selectivity over SAPO catalysts at a temperature in the range of 350 to 450°C and weight hourly space velocity (W.H.S.V) in the range of 0.25 to 1.0 per hour. Accordingly, the present invention provides an improved process for the preparation of benzonitrile which comprises passing a feed consisting of toluene, ammonia in a molar ratio in the range of 1:1 to 1:20, water and air or oxygen gas in a feed ratio of 60 cc per minute of ammonia over a silico-alumino-phosphate (SAPO) catalyst, prepared by the process such as herein described at a temperature in the range of 300-450°C and weight hourly space velocity of liquid products in the range of 0.25 to 1.0 per hour to obtain benzonitrile. In an embodiment of the present invention the molar ratio of the toluene and ammonia is 1:4.5. In another embodiment of the present invention the feed ratio of air or oxygen is 60 cc per minute. The catalysts are prepared in general in the following way. Al2(S04)3, H3P04, Na2 Si03, with or without NaCI and tetrapropylammonium bromide (TPA) or tetrabutylammonium bromide (TBA) used as a template, are mixed in distilled water in the pH range of 7.0 to 12.0. The slurry is mixed for at least 2 hours at room temperature with constant stirring and the pH is adjusted by aqueous ammonia. The slurry was put into an autoclave for autoclaving under autogeneous pressure in the temperature range of 150 to 220°C for 24 hrs to 80 hrs till complete crystallization was achieved. The mixture was filtered and washed with distilled water. The solid catalyst was dried in oven at 120°C over night. The organic template was removed by the activation of the catalyst at 500-550°C for 5-15 hrs. Then the calcined material was modified by promoters like Sb203 or oxides of the elements active as promoters in the respective reactions. Basically in alumino-phosphate molecular sieves the AI:P atomic ratio is 1:1. We have substituted P partially by V as discussed and claimed in the copending patent No.1459/Del/95. Al also may be substituted partially by V; with the corresponding variation in the atomic ratio. The above said reactions were carried out in a tubular, down-flow pyrex reactor with 20 mm internal diameter. The reaction mixture was fed from top using syringe pump (Sage Instruments, USA). The product was cooled by using ice-cooled water and collected at the bottom. The required number of ice-cooled traps were used to collect the total amount of products. The products were analysed by using SE-30 (5%) and OV-17 columns. The analysis was confirmed by mass spectra and GC-mass. The reaction of toluene with ammonia in the presence of air (or oxygen) was carried out over VAPO (TPA-B), VAPO (TPA-C), VAPO (TPA-D). The temperature was varied from 250 to 420°C. The molar ratio of toluene to ammonia was 1:4.5 (30 cc per min of ammonia). The following examples are given to illustrate the process of the present invention,however these should not be construed to limit the scope of invention. EXAMPLE - 1 In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 per min) ammonia and 60 cc per min air over 4 gm VAPO(TPA-B) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 63.5 % based on toluene at 69.8 % conversion of toluene. EXAMPLE -2 In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 per min) ammonia and 60 cc per min air over 4 gm VAPO(TPA-C) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 19.8 % based on toluene at 30.5 % conversion of toluene. EXAMPLE -3 In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 per min) ammonia and 60 cc per min air over 4 gm VAPO(TPA-D) at 400° C and 0.5 hr-1 W.H.S.V. of liquid feed : the yield of benzonitrile was 12.4 % based on toluene at 15.1 % conversion of toluene. Advantages of the present invention are as follows: 1. This invention provides a process for the preparation of benzonitrile in one step. 2. According to present process the formation of CO, CO2 and high boiling products are minimised which creates environmental and disposal problems. 3. Present process provides the yield of benzonitrile (>60 %) . We claim : An improved process for the preparation of benzonitrile which comprises passing a feed consisting of toluene, ammonia in a molar ratio in the range of 1:1 to 1:20, water and air or oxygen gas in a feed ratio of 60 cc per minute of ammonia over a silico-alumino-phosphate (SAPO) catalyst, prepared by the process such as herein described at a temperature in the range of 300-450°C and weight hourly space velocity of liquid products in the range of 0.25 to 1.0 per hour to obtain benzonitrile. An improved process as claimecf in claim 1 wherein the molar ratio of toluene and ammonia is 1:4.5 preferably. An improved process for the preparation of benzonitrile substantially as herein described with reference to the examples.

Full Text

This invention relates to an improved process for the preparation of benzonitrile. The present invention particularly relates to an improved process for the preparation of benzonitrile. According to the process of the present invention, toluene is reacted with ammonia and air in the presence of crystalline, porous vanadium aluminophpsphates(VAPO) catalyst. The process of preparing the above catalyst has been described and claimed in our copending application number 1459/del/95. In the presently known process, benzonitrile can be produced from ammox-idation.
The conventional catalysts have been amorphous in nature and not shape selective catalysts. These catalysts have been employed in mostly fixed bed reactors. The following patents have discussed the preparation of nitriles of present interest, e.g. Eur.Pat; Appl. EP 37173 (1981), US Patent 4876348 (1989),US Patent 4603 207 (1986), Eur. Pat 0037123A1 (1981), Brit. Patent 77746 (1957), Ger. (East) DDPatent 241903 (1985), US Patent 3981879 (1976), US Patent 2839535 (1958), US Patent 2510605 (1950) , US Patent 3981879 (1976) . In these inventions the yield of nitrile may or may not be highly selective. Particularly high-boiling products, CO,C02 were formed, due to the amorphous nature of the catalysts. The high-boiling products create environmental and disposal problems.
The object of the present invention is to provide an improved process for the preparation of benzonitrile employing porous active catalytic materials. The other objective of the invention is to provide a process for the preparation of nitriles
wherein the formation of CO, C02 and high-boiling products are minimized.
The present invention provides >50% yield of benzonitrile from toluene ammoxidation in one step with very high selectivity over SAPO catalysts at a temperature in the range of 350 to 450°C and weight hourly space velocity (W.H.S.V) in the range of 0.25 to 1.0 per hour.
Accordingly, the present invention provides an improved process for the preparation of benzonitrile which comprises passing a feed consisting of toluene, ammonia in a molar ratio in the range of 1:1 to 1:20, water and air or oxygen gas in a feed ratio of 60 cc per minute of ammonia over a silico-alumino-phosphate (SAPO) catalyst, prepared by the process such as herein described at a temperature in the range of 300-450°C and weight hourly space velocity of liquid products in the range of 0.25 to 1.0 per hour to obtain benzonitrile.
In an embodiment of the present invention the molar ratio of the toluene and ammonia is 1:4.5.
In another embodiment of the present invention the feed ratio of air or oxygen is 60 cc per minute.
The catalysts are prepared in general in the following way. Al2(S04)3, H3P04, Na2 Si03, with or without NaCI and tetrapropylammonium bromide (TPA) or tetrabutylammonium bromide (TBA) used as a template, are mixed in distilled water in the pH range of 7.0 to 12.0. The slurry is mixed for at least 2 hours at room temperature with constant stirring and the pH is adjusted by aqueous ammonia. The slurry was put into an autoclave for autoclaving under autogeneous pressure in the temperature range of 150 to
220°C for 24 hrs to 80 hrs till complete crystallization was achieved. The mixture was filtered and washed with distilled water. The solid catalyst was dried in oven at 120°C over night. The organic template was removed by the activation of the catalyst at 500-550°C for 5-15 hrs. Then the calcined material was modified by promoters like Sb203 or oxides of the elements active as promoters in the respective reactions. Basically in alumino-phosphate molecular sieves the AI:P atomic ratio is 1:1. We have substituted P partially by V as discussed and claimed in the copending patent No.1459/Del/95. Al also may be substituted partially by V; with the corresponding variation in the atomic ratio.
The above said reactions were carried out in a tubular, down-flow pyrex reactor with 20 mm internal diameter. The reaction mixture was fed from top using syringe pump (Sage Instruments, USA). The product was cooled by using ice-cooled water and collected at the bottom. The required number of ice-cooled traps were used to collect the total amount of products. The products were analysed by using SE-30 (5%) and OV-17 columns. The analysis was confirmed by mass spectra and GC-mass.
The reaction of toluene with ammonia in the presence of air (or oxygen) was carried out over VAPO (TPA-B), VAPO (TPA-C), VAPO (TPA-D). The temperature was varied from 250 to 420°C. The molar ratio of toluene to ammonia was 1:4.5 (30 cc per min of ammonia).
The following examples are given to illustrate the process of the present invention,however these should not be construed to limit the scope of invention.
EXAMPLE - 1
In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 per min) ammonia and 60 cc per min air over 4 gm VAPO(TPA-B) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 63.5 % based on toluene at 69.8 % conversion of toluene.
EXAMPLE -2
In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 per min) ammonia and 60 cc per min air over 4 gm VAPO(TPA-C) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 19.8 % based on toluene at 30.5 % conversion of toluene.
EXAMPLE -3
In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 per min) ammonia and 60 cc per min air over 4 gm VAPO(TPA-D) at 400° C and 0.5 hr-1 W.H.S.V. of liquid feed : the yield of benzonitrile was 12.4 % based on toluene at 15.1 % conversion of toluene.
Advantages of the present invention are as follows:
1. This invention provides a process for the preparation of benzonitrile in one step.
2. According to present process the formation of CO, CO2 and high boiling products are minimised which creates environmental and disposal problems.
3. Present process provides the yield of benzonitrile (>60 %) .

We claim :
An improved process for the preparation of benzonitrile which comprises passing a feed consisting of toluene, ammonia in a molar ratio in the range of 1:1 to 1:20, water and air or oxygen gas in a feed ratio of 60 cc per minute of ammonia over a silico-alumino-phosphate (SAPO) catalyst, prepared by the process such as herein described at a temperature in the range of 300-450°C and weight hourly space velocity of liquid products in the range of 0.25 to 1.0 per hour to obtain benzonitrile. An improved process as claimecf in claim 1 wherein the molar ratio of toluene and ammonia is 1:4.5 preferably.
An improved process for the preparation of benzonitrile substantially as herein described with reference to the examples.

Documents:

959-del-1995-abstract.pdf

959-del-1995-claims.pdf

959-del-1995-correspondence-others.pdf

959-del-1995-correspondence-po.pdf

959-del-1995-description (complete).pdf

959-del-1995-form-1.pdf

959-del-1995-form-2.pdf

959-del-1995-form-4.pdf

959-del-1995-form-5.pdf

959-del-1995-form-6.pdf

959-del-1995-form-9.pdf

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Patent Number

190761

Indian Patent Application Number

959/DEL/1995

PG Journal Number

34/2003

Publication Date

23-Aug-2003

Grant Date

15-Mar-2004

Date of Filing

25-May-1995

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	REVUR RAMCHANDRA RAO	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD, INDIA
2	MACHIRAJU SUBRAHMANYAM	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD, INDIA
3	ALLA VENKAT RAMA RAO	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD, INDIA
4	SHIVANAND JANARDAN KULKARNI	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD, INDIA
5	SURESH FARSINAVIS	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD, INDIA
6	PANJA KANTA RAO	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD, INDIA

PCT International Classification Number

C07C 121/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA