CN110655443A

CN110655443A - Novel chlorination process of 4-chlorotrifluoromethane

Info

Publication number: CN110655443A
Application number: CN201810682779.8A
Authority: CN
Inventors: 郑龙生; 方东; 张亮; 李付香
Original assignee: JIANGSU FENGHUA CHEMICAL INDUSTRIAL Co Ltd
Current assignee: JIANGSU FENGHUA CHEMICAL INDUSTRIAL Co Ltd
Priority date: 2018-06-28
Filing date: 2018-06-28
Publication date: 2020-01-07

Abstract

The invention discloses a novel chlorination process of 4-trichloro-4-chlorotoluene. 4-chlorotoluene is used as a raw material, and the 4-chlorotrifluoromethylbenzene target compound is obtained through the steps of side chain chlorination, reduced pressure rectification, neutralization, filtration and the like. Compared with the prior art, the invention adopts a step-by-step catalytic process, the reaction condition is mild, and no special equipment is added in the production process; the side chain trichlorination selectivity is high, the generation of monochloride, dichlorate, side chain and benzene ring chlorination byproducts is greatly reduced, the separation and purification process is simplified, and the emission of organic three wastes is reduced; the yield is about 99 percent and is about 10 percent higher than that of the common chlorination process.

Description

Novel chlorination process of 4-chlorotrifluoromethane

Technical Field

The invention relates to a preparation method of a pesticide chemical intermediate product, in particular to a novel chlorination process of 4-trichloro-4-chlorotoluene. The method is suitable for the occasion of synthesizing the 4-trichloro toluene by catalyzing side chain chlorination by taking the 4-chlorotoluene as a raw material.

Background

4-trichloro toluene chloride is an important medical intermediate, and a side chain chlorine atom in a molecular structure of the 4-trichloro toluene chloride can have special activity after being substituted by a fluorine atom, so that the 4-trichloro toluene chloride can be widely applied to the fields of fine organic synthesis such as medicines, pesticides, dyes and the like. Wherein, the most used amount at present is to synthesize diphenyl ether herbicides, such as lactofen, fomesafen, fluoroglycofen-ethyl, dichlorofluroxypyr, oxyfluorfen, fluroxypyr, acifluorfen, fluoronaphthyl oxalate, fluoroglycofen ester, HC-252, SN106279 and the like, and in addition, pyrazole pesticide fipronil can be synthesized. The herbicide is sold in the market at home and abroad, and the yield and sales are increased year by year.

Currently, the known synthesis method is shown as formula 1: 4-chlorotoluene (1) is taken as a raw material, 4-chlorotrifluoromethylbenzene (2) is obtained through side chain chlorination,

formula 1

The yield of the side chain chlorination method is about 90 percent, the production process is complicated, and a large amount of by-products, namely hydrochloric acid and sodium hypochlorite solution are generated and accompanied with exhaust emission. In addition, monochloride (3), dichloride (4), side chains and a benzene ring chlorination by-product (5) are generated during side chain chlorination, so that the conversion rate and yield of a target product are low, the separation and purification process is complicated and time-consuming, and the amount of organic three wastes is large.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art and provide a novel method for synthesizing 4-chlorotrifluoromethylene by catalyzing side chain chlorination, wherein 4-chlorotoluene is used as a raw material, a mixture of inorganic salt cuprous chloride and copper powder is used as a catalyst, and the side chain chlorination is catalyzed to obtain a target compound of the 4-chlorotrifluoromethylene.

The technical solution of the invention is as follows:

catalytic side chain chlorination: putting 4-chlorotoluene into a reaction kettle, heating to a certain temperature, adding a catalyst in batches, and introducing dry chlorine gas at a flow rate of 40-80 m³And h, adding the catalyst every 15 minutes, controlling the temperature to be 115-125 ℃, and reacting for more than 20 hours. When the content of the 4-chlorotrifluoromethane is less than 0.5 percent, stopping introducing chlorine, and introducing dry air instead to discharge unreacted chlorine, hydrogen chloride gas generated by the reaction and gaseous impurities in the reaction kettle to obtain a crude product of the 4-chlorotrifluoromethane.

(2) And (3) rectification: and (2) carrying out vacuum rectification on the crude product obtained in the step (1) to obtain the 4-trichloro-toluene chloride with the purity of more than 99 wt%.

(5) And (3) neutralization packaging: and (3) transferring the 4-chlorotrifluoromethane with the purity of more than 99wt% obtained in the step (2) into a neutralization kettle, adding a certain amount of sodium carbonate, stirring, neutralizing until the pH value is neutral, filtering, and packaging the finished product of the 4-chlorotrifluoromethane.

The catalyst in the step (1) is: cuprous chloride and copper powder.

The mass ratio of each component of the catalyst is as follows: 1:1.

The catalyst was added in portions, with 15 minutes intervals between each portion, and the portions were added in 4 portions.

The mass ratio of the raw materials used in the reaction is as follows: 4-chlorotoluene: catalyst = 1: 0.05 to 0.1.

The temperature required by the reaction is 115-125 ℃.

The time required for the reaction is 20-24 hours.

The vacuum rectification conditions in the step (2) are as follows: the vacuum degree is 0.095Mpa, the reflux ratio is 5: 2-3: 1, fractions with the gas phase temperature of 145-148 ℃ at the top of the tower are collected, and the target compound is obtained after condensation.

The chemical reaction formula of the invention is as follows:

due to the adoption of the technical scheme, the invention has the beneficial effects that the economic benefit and the social benefit are obvious:

1. the method takes 4-chlorotoluene as a raw material to produce 4-chlorotrifluoromethylene, and the raw material has wide sources and low price;

2. the catalyst adopted by the invention is a common chemical raw material sold in the market, and has wide source and lower cost;

3. the invention adopts the step-by-step catalytic process, the reaction condition is mild, and no special equipment is added in the production process;

4. the side chain trichloro-selective catalyst has high side chain trichloro-selective performance, greatly reduces the generation of monochloride, dichlorinate, side chain and benzene ring chloro-byproducts, simplifies the separation and purification process, and reduces the emission of organic three wastes;

5. the yield of the invention is about 99 percent, which is about 10 percent higher than the yield of the common chlorination process.

Detailed description of the invention

The following examples further illustrate the invention in order to provide a better understanding of the invention. The examples do not limit the scope of the invention in any way. Modifications and adaptations of the present invention within the scope of the claims may occur to those skilled in the art and are intended to be within the scope and spirit of the present invention.

Example 1

(1) Catalytic side chain chlorination: putting 800g of 4-chlorotoluene into a 3L reaction kettle, heating to 115 ℃, adding a catalyst, and introducing dry chlorine gas at a flow rate of 40-80 m³And h, adding the catalyst every 15 minutes, adding 40g of the catalyst in total, controlling the temperature to be 115-117 ℃, and reacting for 24 hours. Stopping introducing chlorine when the content of the 4-chlorotrifluoromethane is less than 0.5 percent, and introducing dry air to discharge unreacted chlorine, hydrogen chloride gas generated by reaction and gaseous impurities in the reaction kettle to obtain a crude product of the 4-chlorotrifluoromethane;

(2) and (3) rectification: carrying out reduced pressure rectification on the crude product under the conditions that the vacuum degree is 0.095Mpa and the reflux ratio is 5:2, collecting fractions with the gas phase temperature of 145-148 ℃ at the top of the tower, and condensing to obtain 4-trichlorotoluene with the purity of 99.1 wt%;

(3) and (3) neutralization packaging: transferring the 4-trichloro toluene with the purity of 99.1 weight percent into a neutralization kettle, adding a certain amount of sodium carbonate, stirring and neutralizing until the pH value is neutral, filtering, and packaging the finished product of the 4-trichloro toluene.

Example 2

(1) Catalytic side chain chlorination: putting 800g of 4-chlorotoluene into a 3L reaction kettle, heating to 115 ℃, adding a catalyst, and introducing dry chlorine gas at a flow rate of 40-80 m³And h, adding the catalyst every 15 minutes, adding 80g of catalyst in total, controlling the temperature to be 120-125 ℃, and reacting for 22 hours. Stopping introducing chlorine when the content of the 4-chlorotrifluoromethane is less than 0.5 percent, and introducing dry air to discharge unreacted chlorine, hydrogen chloride gas generated by reaction and gaseous impurities in the reaction kettle to obtain a crude product of the 4-chlorotrifluoromethane;

(2) and (3) rectification: carrying out reduced pressure rectification on the crude product under the conditions that the vacuum degree is 0.095Mpa and the reflux ratio is 3:1, collecting fractions with the gas phase temperature of 145-148 ℃ at the top of the tower, and condensing to obtain 4-trichloro toluene with the purity of 99.3 wt%;

(3) and (3) neutralization packaging: transferring the 4-trichloro toluene with the purity of 99.3wt% into a neutralization kettle, adding a certain amount of sodium carbonate, stirring and neutralizing until the pH value is neutral, filtering, and packaging the finished product of the 4-trichloro toluene.

Example 3

(1) Catalytic side chain chlorination: putting 800g of 4-chlorotoluene into a 3L reaction kettle, heating to 115 ℃, adding a catalyst, and introducing dry chlorine gas at a flow rate of 40-80 m³And h, adding the catalyst every 15 minutes, adding 60g of the catalyst in total, controlling the temperature to be 115-120 ℃, and reacting for 20 hours. Stopping introducing chlorine when the content of the 4-chlorotrifluoromethane is less than 0.5 percent, and introducing dry air to discharge unreacted chlorine, hydrogen chloride gas generated by reaction and gaseous impurities in the reaction kettle to obtain a crude product of the 4-chlorotrifluoromethane;

(2) and (3) rectification: carrying out reduced pressure rectification on the crude product under the conditions that the vacuum degree is 0.095Mpa and the reflux ratio is 3:1, collecting fractions with the gas phase temperature of 145-148 ℃ at the top of the tower, and condensing to obtain 4-trichloro toluene with the purity of 99.5 wt%;

(3) and (3) neutralization packaging: transferring 4-trichloro toluene with purity of more than 99.5wt% into a neutralization kettle, adding a certain amount of sodium carbonate, stirring and neutralizing until pH is neutral, filtering, and packaging the 4-trichloro toluene.

Example 4

(1) Catalytic side chain chlorination: putting 600kg of 4-chlorotoluene into a 3000L reaction kettle, heating to 115 ℃, adding a catalyst, introducing dry chlorine gas at a flow rate of 40-80 m³And h, adding the catalyst every 15 minutes, adding 40kg of catalyst in total, controlling the temperature to be 115-125 ℃, and reacting for 24 hours. Stopping introducing chlorine when the content of the 4-chlorotrifluoromethane is less than 0.5 percent, and introducing dry air to discharge unreacted chlorine, hydrogen chloride gas generated by reaction and gaseous impurities in the reaction kettle to obtain a crude product of the 4-chlorotrifluoromethane;

(2) and (3) rectification: carrying out reduced pressure rectification on the crude product under the conditions that the vacuum degree is 0.095Mpa and the reflux ratio is 5: 2-3: 1, collecting fractions with the gas phase temperature of 145-148 ℃ at the top of the tower, and condensing to obtain 4-chlorotrifluoromethane with the purity of 99.3 wt%;

(3) and (3) neutralization packaging: transferring the 4-trichloro toluene with the purity of 99.3wt% into a neutralization kettle, adding a certain amount of sodium carbonate, stirring and neutralizing until the pH value is neutral, filtering, and packaging the 4-trichloro toluene.

Claims

1. A novel chlorination process of 4-trichloro-4-toluene is characterized by comprising the following steps: 4-chlorotoluene is taken as a raw material, and a 4-trichloro toluene target compound is obtained through the steps of side chain chlorination, reduced pressure rectification, neutralization, filtration and the like; wherein the side chain chlorination step is to put 4-chlorotoluene into a reaction kettle, heat the mixture to a certain temperature, add the mixture of cuprous chloride and copper powder in batches as a catalyst, and start to introduce dry chlorine gas with the flow rate of 40-80 m³And h, controlling the temperature to be 115-125 ℃, reacting for more than 20 hours, stopping introducing chlorine when the content of the 4-chlorotrifluoromethane is less than 0.5%, introducing dry air instead of the chlorine which is not reacted in the reaction kettle, hydrogen chloride gas generated by the reaction and gaseous impurities to discharge the chlorine, the hydrogen chloride gas and the gaseous impurities to obtain a crude product of the 4-chlorotrifluoromethane, and rectifying, neutralizing and filtering to obtain a finished product of the 4-chlorotrifluoromethane.

2. The novel chlorination process of 4-chlorotrifluoromethylene as claimed in claim 1, characterized in that: the catalyst in the side chain chlorination step is prepared from the following components in a mass ratio of 1:1 cuprous chloride and copper powder.

3. The novel chlorination process of 4-chlorotrifluoromethylene as claimed in claim 1, characterized in that: the mass ratio of the raw materials used in the side chain chlorination reaction is as follows: 4-chlorotoluene: catalyst = 1: 0.05 to 0.1.

4. The novel chlorination process of 4-chlorotrifluoromethylene as claimed in claim 1, characterized in that: the catalyst in the side chain chlorination step was added in 4 batches, each batch separated by 15 minutes.

5. The novel chlorination process of 4-chlorotrifluoromethylene as claimed in claim 1, characterized in that: the vacuum rectification conditions are as follows: the vacuum degree is 0.095Mpa, the reflux ratio is 5: 2-3: 1, and fractions with the gas phase temperature of 145-148 ℃ at the top of the tower are collected.