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 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.

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 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.

Full Text	This invention relates to an improved process for the preparation of benzonitrile. Particularly this invention relates to an improved process for the preparation of benzonitrile from toluene over silico - alumino - phosphate catalysts via ammoxida-tion. According to the process of the present invention toluene is reacted with ammonia and air in the presence of crystalline , porous silico-aluminophosphates(SAPO) catalyst. The process of preparing the above catalyst has been described and claimed in our copending application number NF 225/96. In the presently known process, benzonitrile can be produced from ammoxidation. 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,CO2 were formed, due to the amorphous nature of the catalysts. The high-boling products create environmental and disposal problems. The object of the present invention is to provide an improved process for the preparation of nitriles employing porous active catalytic materials. The other objective of the invention is to provide a process for the preparation of nitriles wherein 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. AI2(S04)3, H3PO4, 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 aluminophosphate molecular sieves the Al:P atomic ratio is 1:1. We have substituted P partially by Si as described and claimed in the copending patent number : NF 225/96. Al also may be substituted partially by Si with the corresponding variation in the atomic ratio. The above said reactions were carried out in a tubular, down-flow pyrex reactortor 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 SAPO(TPA),SAPO(TBA),SAPO-37, at a temperature range of 300 - 450 °C. The molar ratio of toluene to ammonia was in the range of 1:1 to 1:20. 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 cc per min) ammonia and 60 cc per min air over 4 gm SAPO(TriPA) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed : the yield of benzonitrile was 56.7 % based on toluene at 67.8 % conversion of toluene. EXAMPLE -2 In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 cc per min) ammonia and 60 cc per min air over 4 gm SAPO-37 at 420°C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 43.5 % based on toluene at 46.6 % conversion of toluene. EXAMPLE -3 In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 cc per min) ammonia and 60 cc per min air over 4 gm SAPO(TPA) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 23.5 % based on toluene at 25.2 % conversion of toluene. EXAMPLE -4 In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 cc per min) ammonia and 60 cc per min air over 4 gm SAPO(DPA) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 47.6 % based on toluene at 50.9 % conversion of toluene. EXAMPLE -5 In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 cc per min) ammonia and 60 cc per min air over 4 gm SAPO(TBA) at 420° C and 0.5 hr"1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 30.2 % based on toluene at 31.5 % conversion of toluene. Advantages of the present invention are as follows: 1. The process of present invention is one step process for the preparation of benzonitrile from toluene. 2. According to present process the formation of CO, C02 and high boiling products are minimised which solves the problem of disposal. We claim: 1. 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. 2. An improved process as claimed in claim 1 wherein the molar ratio of toluene and ammonia is 1:4.5 preferably. 3. 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. Particularly this invention relates to an improved process for the preparation of benzonitrile from toluene over silico - alumino - phosphate catalysts via ammoxida-tion. According to the process of the present invention toluene is reacted with ammonia and air in the presence of crystalline , porous silico-aluminophosphates(SAPO) catalyst. The process of preparing the above catalyst has been described and claimed in our copending application number NF 225/96. In the presently known process, benzonitrile can be produced from ammoxidation.
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,CO2 were formed, due to the amorphous nature of the catalysts. The high-boling products create environmental and disposal problems.
The object of the present invention is to provide an improved process for the preparation of nitriles employing porous active catalytic materials. The other objective of the invention is to provide a process for the preparation of nitriles wherein
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. AI2(S04)3, H3PO4, 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 aluminophosphate molecular sieves the Al:P atomic ratio is 1:1. We have substituted P partially by Si as described and claimed in the copending patent number : NF 225/96. Al also may be substituted partially by Si with the corresponding variation in the atomic ratio.
The above said reactions were carried out in a tubular, down-flow pyrex reactortor 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 SAPO(TPA),SAPO(TBA),SAPO-37, at a temperature range of 300 - 450 °C. The molar ratio of toluene to ammonia was in the range of 1:1 to 1:20.
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 cc per min) ammonia and 60 cc per min air over 4 gm SAPO(TriPA) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed : the yield of benzonitrile was 56.7 % based on toluene at 67.8 % conversion of toluene.
EXAMPLE -2
In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 cc per min) ammonia and 60 cc per min air over 4 gm SAPO-37 at 420°C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 43.5 % based on toluene at 46.6 % conversion of toluene.
EXAMPLE -3
In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 cc per min) ammonia and 60 cc per min air over 4 gm SAPO(TPA) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 23.5 % based on toluene at 25.2 % conversion of toluene.
EXAMPLE -4
In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 cc per min) ammonia and 60 cc per min air over 4 gm SAPO(DPA) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 47.6 % based on toluene at 50.9 % conversion of toluene.
EXAMPLE -5
In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 cc per min) ammonia and 60 cc per min air over 4 gm SAPO(TBA) at 420° C and 0.5 hr"1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 30.2 % based on toluene at 31.5 % conversion of toluene.
Advantages of the present invention are as follows:
1. The process of present invention is one step process for the preparation of benzonitrile from toluene.
2. According to present process the formation of CO, C02 and high boiling products are minimised which solves the problem of
disposal.

We claim:
1. 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.
2. An improved process as claimed in claim 1 wherein the molar ratio of toluene and ammonia is 1:4.5 preferably.
3. An improved process for the preparation of benzonitrile substantially as herein described with reference to the examples.

Documents:

958-del-1995-abstract.pdf

958-del-1995-claims.pdf

958-del-1995-correspondence-others.pdf

958-del-1995-correspondence-po.pdf

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

958-del-1995-form-1.pdf

958-del-1995-form-2.pdf

958-del-1995-form-4.pdf

958-del-1995-form-5.pdf

958-del-1995-form-6.pdf

958-del-1995-form-9.pdf

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Patent Number

190760

Indian Patent Application Number

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