SU759506A1 - Method of preparing substituted benzonitriles - Google Patents

Description

The invention relates to an improved method for producing substituted benzonitriles of the general formula

she is 5

Where A = H or CH ^, 10

which can be used

upon receipt and stabilization of Polymeric materials, in agriculture and organic synthesis :.

A method of obtaining 4-chloro-, 5 -M-tolunitrile and 4-chlorois phthalic acid dinitrile by oxidative ammonolysis of 4-chloro-** .- xylene on bismuth molybdate at 350-400 ° С.

Under these conditions, isomeric 4-chloro-M-tolunitriles and dinitrile of 4-chloro-isophthalic acid in a kebol amount were obtained with a yield of 61% (in terms of the reacted starting material). The total conversion of raw materials 25 is about 30%.

The disadvantages of this method are the destruction of the molecule due to the high temperature in the reaction zone and hydrogen cyanide is formed 39

2

and carbon dioxide, which is difficult to utilize, as well as low yield and selectivity of the process.

Closest to the proposed technical essence of the method of obtaining substituted benzonitriles, the specified General formula ', by oxidative ammonolysis of chloroxylenes in the vapor phase in the presence of tin vanadate or vanadium pentoxide. The total yield of the 2nd 3-chlorotolunitriles does not exceed 38%. The selectivity of the process on the sum of mono- and dinitriles is 70-80%. The process is conducted at 380-400 ° C and the weight ratio of air and ammonia, equal to (11-22): 1 TH ·

The disadvantages of this method are the relatively low selectivity, the low yield of the target product, the high temperature of the reactions, and the release of NSC, CO, CO ₂ , which are highly toxic (especially NSY and difficult to utilize. '

The purpose of the invention is to increase the yield and selectivity of the process.

This goal is achieved using the method of obtaining substituted benzonitriles, specified

3

'g'- · '. ··' '. · -Г ·· -.- ••• to-'Х · -Чг - /: ·· С ·· -'. ·

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of the general formula, by oxidative ammonolysis of the corresponding substituted toluene at elevated temperature in the presence of a catalyst, ps of which the process is carried out in the Liquid phase in the environment of benzonitrile with

At a temperature of 140-180 ° C and a weight ratio of oxygen and ammonia (30-50): 1, and as a catalyst a mixture of cobalt acetate and ammonium bromide is used, preferably, θ Completely in a mole ratio of 1.16: 1. ^one

-The proposed method allows to obtain the target products (mononitriles of chlorine-substituted aromatic acids) with a yield of up to 80% with a selectivity of 96%.

Example 1. Experiments. Carried out in a laboratory setup at atmospheric pressure. The components of the ammonia-oxygen mixture — oxygen and ammonia from the cylinders — enter the mono-system and rheometer system, after which they are mixed in a mixer, from where the gas mixture is fed to the reactor.

The latter is a glass flask with a capacity of 300 cm / Pyrex, made of glass, equipped with an inlet for supplying the gas mixture, a pocket for the thermophone ’with a special device for

sampling from the reactor in the course of the reaction. At the exit of the reactor, a system of reverse refrigerators connected to the Dean-Stark trap is installed,

“- for the recovery and separation of the initial hydrocarbon from the reaction water. ^ 5

The reactor is equipped with an efficient mixing device in the form of a high-speed mixer with a syringe gate. In terms of experience, the number of revolutions of the mixer is 100-1200 rpm.

The heating of the reaction apparatus is carried out using a special electric furnace, and the temperature in the reactor is monitored and controlled automatically by means of an EPV and a thermocouple placed with

Pocket's power to the reaction zone.

Experiments are carried out in the next after ^! ^ "More info: \ 7th <solid product P-chlorotoluene 63.8 g, solvent benzonitrile 126.1 g, catalyst - 50

cobalt acetate 7.4 g, and ammonium bromide 2.5 g loaded into the reactor and the mixture is heated. Upon reaching the test temperature of 170 ° C, an oxygen-ammonia mixture (oxygen

200.2 g and ammonia 6.9 g) and this moment is taken as the start of the reaction.

Reaction time 3.5 h. '

The resulting reaction mass (207.1 g) is subjected to rectification. First, the unreacted 60 are distilled off.

the initial product - And - chlorotoluene 10.0 g (fraction 162-163 ° C) and a solution agent - benzonitrile 125.0 g (fraction 190-191 * C), and then the resulting reaction products -. P-chlorobenzo, nitrile 55 , 8 g (fraction 222-223's) and chlorobenzoic acid 2.0 g (fraction 256-257 ° C).

The spent catalyst (9.0 g) remains in the residue, η-ChlorobenzonitRil is separated from the impurities of p-chlorobenzoic acid by treatment with an aqueous solution of alkali. Next, p-chlorobenzonitrile in a separating funnel is separated from the alkaline layer, washed with water until neutral, and dried. 55.2 g of p-chlorobenzonitrile are obtained. The alkaline layer is neutralized with hydrochloric acid, the precipitated P-chlorobenzoic acid is filtered off, washed with water until neutral and dried. 0.4 g of p-chlorobenzoic acid is obtained.

Example 1. Experience carried out at 170 ° C for 3.5 hours. Take, g: P-chlorto'luol 63.8 ", benzonitrile 126.1; cobalt acetate 7.4; ammonium bromide 2.5) oxygen 200.2; ammonia 6.9.

Received, g: η-chlorotoluene unreacted 10.0, 'benzonitrile 125.0; unreacted oxygen 178, o; ammonia, unreacted 0.4; spent catalyst 9.0 P-chlorobenzonitrile 55.2 (79.6% for taken p-chlorotoluene, 96.3% for reacted p-chlorotoluene); p-chlorobenzoic acid 2.4, reaction water 20.0, loss 6.9.

Example 2. Experience conducted in example 1, at 150 ⁶ With 4.5 hours Take, g: p-chlorortsluol 64,6; benzonitrile

127.7; cobalt acetate 7.4, ammonium bromide 2.5 / oxygen 193.0, ammonia 6.0.

Received, g: p-chlorotoluene unreacted 18, O; benzonitrile 126.0, unreacted oxygen 174.0; unreacted ammonia 0.5; spent catalyst 8.9; P-chlorobenzonitrile 47.5 (67.7 mol.% Per taken P-chlorotoluene, 96.1% on reacted p-chlorotoluene); P-chlorobenzoic acid 2.2; reaction water 17.5, loss 6.6.

Example 3. The methodology of the experiment is similar to example 1,

Experience conducted at 180 ° C -2h. Take, g: P-chlorotoluene 64.8, ’benzonitrile 128.0; cobalt acetate 7.4, ’ammonium bromide 2.5,’ oxygen 114.4; ammonia 2.3.

Cum, g: P-chlorotoluene unreacted 21.0; benzonitrile 126.5; unreacted oxygen 97.0; unreacted ammonia 0.3; spent catalyst 8.9; P-chlorobenzonitrile 15.1 (21.5 mol.% To taken P-chlorotoluene, 30% to reacted p-chlorotoluene), p-chlorobenzoic acid 35.3, ’reaction water 9.0; loss of 6.3.

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Example 4. The methodology of the experiment is similar to example 1. The experience is carried out at 140 ° C for 3 hours

Take, g: p-chlorotoluene 64, '6, benzonitrile 127.6, ¹ cobalt acetate 7.4; ammonium bromide 2.5, * oxygen 171.6; ammonia 3.4

Received, g: P-chlorotoluene unreacted 51.0, * benzonitrile 126.0, oxygen unreacted 166.0) unreacted ammonia 1.5; spent catalyst 8.9; η-chlorobenzonitrile 11.9 (17 mol.% per p-chlorotoluene taken, 91.2% on reacted P-chlorotoluene) P-chlorobenzoic acid 1.3, reaction water 4.3; loss of 5.7 '.

Example 5. Methodology. experience similar to example 1. The experience is carried out at 170 ° C for 3.5 hours

Taken, g: 4-chloro-o-xylene 64.1 / benzonitrile 126.5; cobalt acetate 7.4; ammonium bromide 2.5, oxygen 200.0, ammonia 6.0.

Obtained, g: 4-chloro-o-xylene unreacted 11.5; benzonitrile 125.0, unreacted oxygen 181.0; ammonia 0.3, ’spent catalyst 8.9; 4-chlorotolunitriles (mixture) 52.6 (76.1 mol% for taken 4-chloro-6-xylene, 95.3% for reacted 4-chloro-0-xylene); 4-chlorotoluic acids (mixture) 2, 9 ', reaction water 18.0,' loss of 6.5.

Example ^. The procedure of the experiment is similar to example 1. The experiment is conducted at 170 ° C for 4 hours.

Taken, g: 2-chloro-p-xylene 64.7; benzonitrile 128.0, cobalt acetate 7.4, ammonium bromide 2.5) oxygen 228.8, * ammonia 6.8.

Received, g: 2-chloro-P-xylene unreacted 9.5; benzonitrile 126.6, unreacted oxygen 209.0 ammonia unreacted ammonia 0.4, spent catalyst 8.8; 2-chlorotoluNitriles (mixture) 55.7

(79.8 mol.% On taken 2-chloro-p-xylene, 95.6% on the reacted 2-chloro-p-xylene-2-chlorotoluic acids (mixture) '2.9) reaction water 19.0, * loss 6 3

five

Claims (2)

Claim 1, method for producing substituted benzonitriles of general formula SI l 5 “0’ BUT where A = H or CH ^ 20 by oxidative ammonolysis of the corresponding substituted toluenes at elevated temperatures in the presence of a catalyst, but this is not the case. in order to increase the selectivity of the process and * · * Increases the yield, the process is carried out in the liquid phase in the environment of benzonitrile at 140-180 ° C and the weight ratio of oxygen and ammonia (30-50): 1, and as a catalyst is used 30 mixture of cobalt acetate and ammonium bromide. 2. The method according to π.1, which differs with i in that a mixture of cobalt acetate and ammonium bromide is used in a molar ratio of 1.16: 1.