CN108129350B

CN108129350B - Preparation method of 2, 4-dichlorobenzonitrile

Info

Publication number: CN108129350B
Application number: CN201810050599.8A
Authority: CN
Inventors: 程卫习; 鲍瑞雪; 范思源; 刘迎; 郑艺; 樊洪波; 谷彦彬; 郝亚楠; 赵荣荣; 王晓君; 王颖颖; 魏克明; 王福; 程宇洁; 薛沛
Original assignee: Henan Luoyang Hydrology And Water Resources Survey Bureau
Current assignee: Henan Luoyang Hydrology And Water Resources Survey Bureau
Priority date: 2018-01-18
Filing date: 2018-01-18
Publication date: 2020-06-05
Anticipated expiration: 2038-01-18
Also published as: CN108129350A

Abstract

The invention relates to a preparation method of 2, 4-dichlorobenzonitrile, which comprises the steps of dissolving 2, 4-dichlorobenzyl alcohol and a nitrogen source in glacial acetic acid, introducing oxygen, adding a mixture of nitric acid and tetramethyl piperidine nitrogen oxide as a catalyst, sealing a reactor, and reacting for 1-24h at the temperature of 25-100 ℃ to obtain the 2, 4-dichlorobenzonitrile. The preparation method of the invention uses nonmetal as catalyst and oxygen as oxidant, thus avoiding the use of metal catalyst and reducing environmental pollution.

Description

Preparation method of 2, 4-dichlorobenzonitrile

Technical Field

The invention relates to the technical field of chemical raw material preparation, and particularly relates to a preparation method of 2, 4-dichlorobenzonitrile.

Background

The 2, 4-dichlorobenzonitrile is a pesticide intermediate with wide application, can be used for producing fluorine-containing benzoyl urea insecticides, herbicides and water quality analysis reagents, and has certain application in the aspects of plastics, dyes, electronic materials and the like. At present, a plurality of synthesis methods of dihalogenobenzonitrile exist, wherein an ammoxidation method is common, and the used raw material is 2, 4-dichlorobenzotrichloride which is used as a catalyst and reacts with ammonia gas under the oxidation of oxygen to prepare the 2, 4-dichlorobenzonitrile. The method has short route and low raw material cost; however, it is difficult to develop a stable catalyst, and the demand for production facilities is high. 2, 4-dichlorobenzonitrile can also be produced by reacting 2, 4-dichlorobenzaldehyde as a raw material with a reagent such as ammonia gas or hydroxylamine hydrochloride in the presence of an oxidizing agent. This method usually achieves a high yield, but the aldehyde raw material used is easily oxidized and deteriorated, is difficult to store, and is expensive. The literature reports that 2, 4-dichlorobenzonitrile is prepared from 2, 4-dichlorobenzamide or 2, 4-dichlorobenzaldehyde oxime as a raw material through a dehydration step. The two methods do not need to use an oxidant, have little pollution, but have high raw material cost and are not beneficial to industrial application. Another method which has been used industrially is the 2, 4-dichlorobenzylamine method. The method comprises two reaction steps of diazotization and cyanidation, and then the 2, 4-dichlorobenzonitrile product is separated out by steam distillation. However, the use of highly toxic sodium cyanide in the cyanidation step creates a serious safety hazard.

Disclosure of Invention

The invention aims to solve the technical problems, provides a preparation method of 2, 4-dichlorobenzonitrile, and solves the problem of high comprehensive cost caused by the use of metal catalysts or dangerous reaction reagents and the like in the existing method.

In order to solve the technical problems, the invention adopts the technical scheme that: a preparation method of 2, 4-dichlorobenzonitrile comprises the steps of dissolving 2, 4-dichlorobenzyl alcohol and a nitrogen source in glacial acetic acid, introducing oxygen, adding a mixture of nitric acid and tetramethylpiperidine nitrogen oxide as a catalyst, sealing a reactor, and reacting at the temperature of 25-100 ℃ for 1-24h to obtain the 2, 4-dichlorobenzonitrile.

The structural formula of 2, 4-dichlorobenzonitrile is as follows:

；

the synthetic route is as follows:

；

the optimization of the preparation method of the 2, 4-dichlorobenzonitrile of the invention is as follows: the nitrogen source is ammonium acetate, ammonium sulfate or ammonium nitrate, and the amount ratio of the nitrogen source to the 2, 4-dichlorobenzyl alcohol substance is 1-3: 1.

The optimization of the preparation method of the 2, 4-dichlorobenzonitrile of the invention is as follows: the pressure of the oxygen is 1-50 atm.

The optimization of the preparation method of the 2, 4-dichlorobenzonitrile of the invention is as follows: the amount ratio of nitric acid to 2, 4-dichlorobenzyl alcohol in the catalyst is 0.1-0.6:1, and the amount ratio of tetramethyl piperidine oxynitride to 2, 4-dichlorobenzyl alcohol in the catalyst is 0.1-0.6: 1.

Advantageous effects

(1) The preparation method of the invention uses nonmetal as catalyst and oxygen as oxidant, thus avoiding the use of metal catalyst and reducing environmental pollution.

(2) The product prepared by the method has high purity and high conversion rate of raw materials, effectively improves the product quality and reduces the production cost.

Drawings

FIG. 1 is a scheme showing the preparation of 2, 4-dichlorobenzonitrile of example 1¹H-NMR chart.

FIG. 2 is the product of example 1, 2, 4-dichlorobenzonitrile¹³C-NMR chart.

Detailed Description

The technical solution of the present invention is further described below with reference to specific embodiments.

Example 1

Magnetons, 2mL of glacial acetic acid, 0.5mmol of 2, 4-dichlorobenzyl alcohol, 1.5mmol of ammonium acetate, 0.15mmol of nitric acid and 0.15mmol of tetramethylpiperidine nitroxide were added in sequence to a glass reaction tube (the pressure of oxygen was 1 atm). After the reaction tube was sealed, it was placed in a heating bath at 50 ℃ and reacted for 12 hours under magnetic stirring. Once the reaction time was reached, the reaction was cooled to room temperature and the product was quantitatively analyzed by internal standard analysis using a gas chromatograph to give a yield of 93% 2, 4-dichlorobenzonitrile product. And then repeating the experiment, and separating and purifying the product by a column chromatography separation method to obtain the 2, 4-dichlorobenzonitrile product. By using¹H-NMR、¹³The structure of the product is determined by C-NMR as shown in FIGS. 1 and 2.

Example 2

Magnetons, 2mL of glacial acetic acid, 0.5mmol of 2, 4-dichlorobenzyl alcohol, 1.5mmol of ammonium acetate, 0.15mmol of nitric acid and 0.15mmol of tetramethylpiperidine nitroxide were added in succession to a glass-lined autoclave. After the reaction kettle is sealed, 10atm of oxygen is filled, the reaction kettle is placed in a heating tank at 50 ℃, and the reaction kettle reacts for 12 hours under magnetic stirring. Once the reaction time was reached, the reaction was cooled to room temperature and the product was quantitatively analyzed by internal standard analysis using a gas chromatograph to give a yield of 77% 2, 4-dichlorobenzonitrile product.

Examples 3 to 4

The ammonium acetate in example 1 was changed to ammonium sulfate and ammonium nitrate, and the other conditions were not changed, yielding yields of the product (gas phase internal standard) of 63% and 52%, respectively.

Examples 5 to 9

The amounts of ammonium acetate in example 1 were changed to 0.5mmol, 0.7mmol, 1mmol, 1.3mmol, and 1.5mmol, and the other conditions were not changed, to obtain yields of the products (gas phase internal standards) of 47%, 72%, 91%, 90%, and 93%, respectively.

Examples 10 to 18

Changing the oxygen pressure in example 2 to 1atm, 3atm, 10atm, 15atm, 20atm, 25atm, 30atm, 40atm, 50atm, and the other conditions were not changed, yields of the products (gas phase internal standard) were 93%, 75%, 77%, 69%, 80%, 72%, 75%, 79%, 82%, respectively.

Examples 19 to 24

The amounts of nitric acid substance in example 1 were changed to 0.05mmol, 0.1mmol, 0.15mmol, 0.2mmol, 0.25mmol and 0.3mmol, and the other conditions were not changed, whereby the yields (gas phase internal standards) of the products were 43%, 81%, 93%, 96%, 90% and 98%, respectively.

Examples 25 to 30

The amounts of substance of tetramethylpiperidine nitroxide in example 1 were changed to 0.05mmol, 0.1mmol, 0.15mmol, 0.2mmol, 0.25mmol and 0.3mmol, and the other conditions were not changed, whereby the yields of the products (gas phase internal standards) were 31%, 73%, 93%, 91%, 89% and 95%, respectively.

Examples 31 to 38

The reaction temperatures in example 1 were changed to 25 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃ and 100 ℃ respectively, and other conditions were not changed, whereby the yields (internal standards in gas phase) of the products were 49%, 77%, 93%, 91%, 86%, 72%, 56% and 32%, respectively.

Examples 39 to 47

The reaction times in example 1 were changed to 1h, 3h, 6h, 9h, 12h, 15h, 18h, 21h, and 24h, respectively, and the other conditions were not changed, resulting in product yields (gas phase internal standards) of 46%, 62%, 69%, 88%, 93%, 96%, 92%, and 95%, respectively.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A preparation method of 2, 4-dichlorobenzonitrile is characterized by comprising the following steps: dissolving 2, 4-dichlorobenzyl alcohol and a nitrogen source in glacial acetic acid, introducing oxygen, adding a mixture of nitric acid and tetramethylpiperidine nitrogen oxide as a catalyst, sealing the reactor, and reacting at the temperature of 25-100 ℃ for 1-24h to prepare 2, 4-dichlorobenzonitrile; the nitrogen source is ammonium acetate.

2. The process according to claim 1, wherein the reaction is carried out in the presence of a solvent selected from the group consisting of: the ratio of the amount of the nitrogen source to the amount of the 2, 4-dichlorobenzyl alcohol substance is 1-3: 1.

3. The process according to claim 1, wherein the reaction is carried out in the presence of a solvent selected from the group consisting of: the pressure of the oxygen is 1-50 atm.

4. The process according to claim 1, wherein the reaction is carried out in the presence of a solvent selected from the group consisting of: the amount ratio of nitric acid to 2, 4-dichlorobenzyl alcohol in the catalyst is 0.1-0.6:1, and the amount ratio of tetramethyl piperidine oxynitride to 2, 4-dichlorobenzyl alcohol in the catalyst is 0.1-0.6: 1.