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 in a molar ratio ranging from 1:1 to 1:20 ammonia, water and air/oxygen the feed ratio ranging from 30 cc per min over a vanadium-silico-alumino-phosphate (VSAPO) catalyst prepared by the process such as herein described at a temperature in the range of 250-450°C and weight hourly space velocity of liquid feed products in the range of 0.25 to 1.0 per hour, recovering the benzonitrile by conventional methods.

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 in a molar ratio ranging from 1:1 to 1:20 ammonia, water and air/oxygen the feed ratio ranging from 30 cc per min over a vanadium-silico-alumino-phosphate (VSAPO) catalyst prepared by the process such as herein described at a temperature in the range of 250-450°C and weight hourly space velocity of liquid feed products in the range of 0.25 to 1.0 per hour, recovering the benzonitrile by conventional methods.

Full Text	This invention elates to an improved process for the preparation of benzonitrile. This invention particularly relates to an improved process for the preparation of benzonitrile from toluene over vanadium silico - alumino - phosphate (VSAPO) cata-lysts via ammoxidation. According to the process of the present invention, toluene is reacted with ammonia and air in the presence of crystalline , porous vanadium silico-aluminophos-phates(VSAPO) catalyst. The process of preparing the above catalyst has been described and claimed in our copending application number 963/Del/95. 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 latent 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 benzonitrile employing Porous active catalyst materials as described and claimed in our copending application No.963/Del/95. The other objective of the present invention is to provide a process for the preparation of benzonitrile wherein the formation of CO, CO2 and high-boiling products are minimized. The present invention provides >90% yield of benzonitrile from toluene ammoxidation in one step with very high selectivity over VSAPO catalysts at a temperature in the range of 250 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 in a molar ratio ranging from 1:1 to 1:20 ammonia, water and air/oxygen the feed ratio ranging from 30 cc per min over a vanadium-silico-alumino-phosphate (VSAPO) catalyst prepared by the process such as herein described at a temperature in the range of 250-450°C and weight hourly space velocity of liquid feed products in the range of 0.25 to 1.0 per hour, recovering the benzonitrile by conventional methods. In an embodiment of the present invention the molar ratio of the toluene and ammonia ranges from 1:1 to 1:20. In another embodiment of the invention wherein the feed ratio of air and oxygen gas is in the range of 30-100 cc per minute. The catalysts are prepared in general in the following way. AI2(SO4)3 H3PO4, Na2SiO3, V2O5 with or without VaCI and tetrapropylammonium bromide (TPA) or tetrabutyl-ammonium bromide (TBA) used as a template, are mixed in distilled water in the pH range of 5.0 to 12.0. The slurry is mixed for atleast 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 hours 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 hours. Then the calcined material was modified by promoters like Sb2O3 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 Si or V elements as discussed and claimed in the copending patent number 1459/Del/95. Al also may be substituted partially by Si or 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 VSAPO (TPA-A), VSAPO(TBA), VSAPO-37, VSAPO (TriPA). The temperature was varied m 250 to 450 C.Tb 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 c.c. per min) ammonia and 60 cc per min air over 4 gm Sb2O3-VSAPO(TPA-A) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ,the yield of benzonitrile was 94.7 % based on toluene at 97.2 % conversion of toluene. EXAMPLE -2 In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 CC per min) ammonia and 6 0 cc per min air over 4 gm VSAPO(TPA-A) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 61.9 % based on toluene at 71.9 % conversion of toluene. EXAMPLE -3 In the reaction of 1.734 gm per hr toluene, 0.228 gm CC 30/per min) ammonia and 60 cc per min air over 4 gm VSAPO(TriPA) at 400° C and 0.5 hr W.H.S.V. of liquid feed ; the yield of 1 anzonitrile was 61.2 % based on toluene at 63.5 % conversion of toluene. EXAMPLE -4 In the reaction of 1.734 gm per hr toluene, 0.228 gm 420 cc per min) ammonial and 60 cc per min air over 4 gm VSAPO-37 a 400° C and 0.5 hr • W.H.S.V. of liquid feed ; the yield of benzonitrile was 28.7 based on toluene at 29.8 % 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 VSAPO(TBA) at 420° C and 0.5 hr"1 W.H.S.V. of liquid feed ; the yield of benzonitril was 24.0 % based on toluene at 26.0 % conversion of toluene. Advantages : 1. The process of present invention is one step process for the preparation of benzonitrile and ammoxidation of toluene is highly selective. 2. According to present process the formation of CO, CO2 and high boiling products are minimised which create environmental and disposal problems. 3 . The process of present invention provides very high yield of benzonitrile (>90 %) . We Claims: 1. An improved process for the preparation of benzonitrile which comprises passing a feed consisting of toluene in a molar ratio ranging from 1:1 to 1:20 ammonia, water and air/oxygen the feed ratio ranging from 30 cc per min over a vanadium-silico-alumino-phosphate (VSAPO) catalyst prepared by the process such as herein described at a temperature in the range of 250-450°C and weight hourly space velocity of liquid feed products in the range of 0.25 to 1.0 per hour, recovering the benzonitrile by conventional methods. 2. An improved process as claimed in claim 1 wherein the feed ratio of air or oxygen is 60 cc per minute. 3. An improved process for the preparation of benzonitrile substantially as herein described with reference to the examples.

Full Text

This invention elates to an improved process for the preparation of benzonitrile. This invention particularly relates to an improved process for the preparation of benzonitrile from toluene over vanadium silico - alumino - phosphate (VSAPO) cata-lysts via ammoxidation. According to the process of the present invention, toluene is reacted with ammonia and air in the presence of crystalline , porous vanadium silico-aluminophos-phates(VSAPO) catalyst. The process of preparing the above catalyst has been described and claimed in our copending application number 963/Del/95. 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 latent 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 benzonitrile employing
Porous active catalyst materials as described and claimed in our copending application No.963/Del/95. The other objective of the present invention is to provide a process for the preparation of benzonitrile wherein the formation of CO, CO2 and high-boiling products are minimized.
The present invention provides >90% yield of benzonitrile from toluene ammoxidation in one step with very high selectivity over VSAPO catalysts at a temperature in the range of 250 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 in a molar ratio ranging from 1:1 to 1:20 ammonia, water and air/oxygen the feed ratio ranging from 30 cc per min over a vanadium-silico-alumino-phosphate (VSAPO) catalyst prepared by the process such as herein described at a temperature in the range of 250-450°C and weight hourly space velocity of liquid feed products in the range of 0.25 to 1.0 per hour, recovering the benzonitrile by conventional methods.
In an embodiment of the present invention the molar ratio of the toluene and ammonia ranges from 1:1 to 1:20.
In another embodiment of the invention wherein the feed ratio of air and oxygen gas is in the range of 30-100 cc per minute.
The catalysts are prepared in general in the following way. AI2(SO4)3 H3PO4, Na2SiO3, V2O5 with or without VaCI and tetrapropylammonium bromide (TPA) or tetrabutyl-ammonium bromide (TBA) used as a template, are mixed in distilled water in the pH range of 5.0 to 12.0. The slurry is mixed for atleast 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 hours 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 hours. Then the calcined material was modified by promoters like Sb2O3 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 Si or V elements as discussed and claimed in the copending patent number 1459/Del/95. Al also may be substituted partially by Si or 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 VSAPO (TPA-A),
VSAPO(TBA), VSAPO-37, VSAPO (TriPA). The temperature was varied
m 250 to 450 C.Tb 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 c.c. per min) ammonia and 60 cc per min air over 4 gm Sb2O3-VSAPO(TPA-A) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ,the yield of benzonitrile was 94.7 % based on toluene at 97.2 % conversion of toluene.
EXAMPLE -2
In the reaction of 1.734 gm per hr toluene, 0.228 gm (30 CC per min) ammonia and 6 0 cc per min air over 4 gm VSAPO(TPA-A) at 420° C and 0.5 hr-1 W.H.S.V. of liquid feed ; the yield of benzonitrile was 61.9 % based on toluene at 71.9 % conversion of toluene.
EXAMPLE -3
In the reaction of 1.734 gm per hr toluene, 0.228 gm CC 30/per min) ammonia and 60 cc per min air over 4 gm VSAPO(TriPA)
at 400° C and 0.5 hr W.H.S.V. of liquid feed ; the yield of
1 anzonitrile was 61.2 % based on toluene at 63.5 % conversion of
toluene.
EXAMPLE -4
In the reaction of 1.734 gm per hr toluene, 0.228 gm 420 cc per min) ammonial and 60 cc per min air over 4 gm VSAPO-37 a 400° C and 0.5 hr • W.H.S.V. of liquid feed ; the yield of benzonitrile was 28.7 based on toluene at 29.8 % 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 VSAPO(TBA) at 420° C and 0.5 hr"1 W.H.S.V. of liquid feed ; the yield of benzonitril was 24.0 % based on toluene at 26.0 % conversion of toluene.
Advantages :
1. The process of present invention is one step process for the preparation of benzonitrile and ammoxidation of toluene is highly selective.
2. According to present process the formation of CO, CO2 and high boiling products are minimised which create environmental and disposal problems.
3 . The process of present invention provides very high yield of benzonitrile (>90 %) .

We Claims:
1. An improved process for the preparation of benzonitrile which comprises passing a feed consisting of toluene in a molar ratio ranging from 1:1 to 1:20 ammonia, water and air/oxygen the feed ratio ranging from 30 cc per min over a vanadium-silico-alumino-phosphate (VSAPO) catalyst prepared by the process such as herein described at a temperature in the range of 250-450°C and weight hourly space velocity of liquid feed products in the range of 0.25 to 1.0 per hour, recovering the benzonitrile by conventional methods.
2. An improved process as claimed in claim 1 wherein the feed ratio of air or oxygen is 60 cc per minute.
3. An improved process for the preparation of benzonitrile substantially as herein described with reference to the examples.

Documents:

960-del-1995-abstract.pdf

960-del-1995-claims.pdf

960-del-1995-correspondence-others.pdf

960-del-1995-correspondence-po.pdf

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

960-del-1995-form-1.pdf

960-del-1995-form-2.pdf

960-del-1995-form-4.pdf

960-del-1995-form-5.pdf

960-del-1995-form-6.pdf

960-del-1995-form-9.pdf

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Patent Number

190762

Indian Patent Application Number

960/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 110 001,INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	ALLA VENKAT RAMA RAO	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	SURESH FARSINAVIS	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD, INDIA
5	REVUR RAMCHANDRA RAO	INDIAN INSTITUTE OF CHEMICAL TECHNOLOGY, HYDERABAD, INDIA
6	SHIVANAND JANARDAN KULKARNI	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