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Method for reducing byproduct chlorotoluene in benzyl chloride production process

A production process, technology of benzyl chloride, applied in the field of photocatalytic reaction of toluene and chlorine to produce benzyl chloride, can solve the problem of reduced activity of substitution reaction, achieve the effect of improving selectivity, reducing heat loss, and reducing deep substitution reaction

Pending Publication Date: 2020-12-15
CHINA SALT CHANGZHOU CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the synthesis and rectification of benzyl chloride need to be carried out at a lower temperature. At the same time, it is necessary to control the metal ion content in the chloride solution or add an inhibitor so that the metal ion catalyzed benzene ring substitution reaction activity is reduced.

Method used

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  • Method for reducing byproduct chlorotoluene in benzyl chloride production process
  • Method for reducing byproduct chlorotoluene in benzyl chloride production process
  • Method for reducing byproduct chlorotoluene in benzyl chloride production process

Examples

Experimental program
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Effect test

Embodiment 1

[0037] Add tributyl phosphate into a photochlorinated glass reaction kettle equipped with an ultraviolet light source according to the mass ratio of 0.05% to toluene (water content 29ppm), mix the materials evenly and preheat to 90°C, and pass the chlorine gas after metal removal into the In the light chlorination reaction kettle, the chlorination reaction temperature is controlled at 90°C during the reaction process, and the hydrogen chloride produced by the reaction is removed from the tail gas treatment process. When the conversion rate of toluene reaches 24.8%, the reaction liquid is added to the aeration kettle and nitrogen is introduced. After 30 minutes of aeration, the acid value of the material was 196ppm, and the temperature dropped to 81.5°C. The material was added to the toluene recovery tower, and the rectification vacuum was controlled to be -0.09MPa. A toluene stream containing a small amount of o- / p-chlorotoluene was obtained at the top of the tower, and the tolu...

Embodiment 2

[0041] Add tributyl phosphate and phenylethylene glycol amine to a photochlorinated glass reactor equipped with an ultraviolet light source at a mass ratio of 0.20% and 0.05% to toluene (water content 29ppm) respectively, mix the materials evenly and preheat to 105°C , pass the chlorine gas after metal removal into the photochlorination reaction kettle, control the chlorination reaction temperature to be 105°C during the reaction, and remove the tail gas treatment process for the hydrogen chloride produced by the reaction. When the toluene conversion rate reaches 20.3%, the reaction solution is Add it into the aeration kettle, and pass nitrogen gas into the aeration tank for 30 minutes, the acid value of the material is 177ppm, the temperature drops to 93.3°C, the material is added to the toluene recovery tower, the rectification vacuum is controlled to -0.08MPa, and a small amount of ortho is obtained at the top of the tower. / toluene flow of p-chlorotoluene, the toluene recov...

Embodiment 3

[0045] Add triethanolamine to toluene (water content 29ppm) in a mass ratio of 0.50% to a photochlorination glass reactor equipped with an ultraviolet light source, mix the materials evenly and preheat to 97°C, and pass the chlorine gas after metal removal into the photochlorination glass reactor. In the chemical reaction kettle, the chlorination reaction temperature is controlled at 97°C during the reaction process, and the hydrogen chloride generated by the reaction is removed from the tail gas treatment process. When the conversion rate of toluene reaches 22.4%, the reaction solution is added to the aeration kettle, and nitrogen is aerated. After 30 minutes, the acid value of the material was 185ppm, and the temperature dropped to 89.6°C. The material was added to the toluene recovery tower, and the rectification vacuum was controlled to be -0.085MPa. A small amount of o- / p-chlorotoluene was obtained at the top of the tower. Tower top material joins in the chlorination react...

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Abstract

The invention discloses a method for reducing byproduct chlorotoluene in a benzyl chloride production process. The method comprises the following steps: by using dehydrated or deironed toluene and chlorine as raw materials and phosphate and other substances as side reaction inhibitors, carrying out heating and photocatalytic reaction in a photochlorination kettle to generate benzyl chloride, and adding the reaction solution into a toluene recovery tower to recover unreacted toluene, and adding the tower bottom material of the recovery tower into a benzyl chloride rectifying tower, and carryingout vacuum rectification and purification to obtain benzyl chloride with the purity of more than 99.9%. According to the method provided by the invention, the content of metal ions in the material can be reduced, and meanwhile, the inhibitors are added to promote partial inactivation of the metal ions, so that the generation of chlorotoluene is reduced, the purity of the benzyl chloride obtainedafter rectification is high, and the impurity content can reach the standard of environment-friendly benzyl chloride.

Description

technical field [0001] The invention relates to a preparation method of benzyl chloride, in particular to a method for photocatalytic reaction of toluene and chlorine to produce benzyl chloride. [0002] technical background [0003] Benzyl chloride, also known as benzyl chloride, is a colorless liquid with a strong pungent odor. Its vapor is irritating to the mucous membranes of the eyes and is a strong lachrymator. At the same time, benzyl chloride is also an intermediate in organic synthesis, widely used in the synthesis of dyes, pesticides, synthetic spices, detergents, plasticizers, and medicines. [0004] There are many synthetic methods for benzyl chloride, mainly containing benzyl alcohol chlorination method using benzyl alcohol and hydrochloric acid as raw materials, chloromethyl method using benzene and formaldehyde (or paraformaldehyde) as raw materials, and using toluene and chlorine gas as raw materials The catalytic chlorination method, etc. Among them, the to...

Claims

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Application Information

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IPC IPC(8): C07C17/14C07C22/04
CPCC07C17/14C07C22/04
Inventor 姚迪王顺利张驰马凯刘向超吴发明朱成明孙运林董亮陶文平
Owner CHINA SALT CHANGZHOU CHEM
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