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New process for preparing p-xylylene dichloride by adopting novel reaction equipment

A technology of para-dichlorobenzyl and reaction equipment, applied in the field of preparing para-dichlorobenzyl, can solve the problems of low single-pass yield of dichlorobenzyl, low content of dichlorobenzyl, low reaction selectivity, etc., so as to reduce the generation of by-products , reduce the reaction temperature, the effect of high initiation efficiency

Pending Publication Date: 2018-08-17
青岛和兴精细化学有限公司
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  • Abstract
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Problems solved by technology

[0003] The preparation process of p-dichlorobenzyl mentioned in previous literatures has the following problems in varying degrees: low reaction selectivity, resulting in the generation of a large number of by-products; The content of benzyl is low, and the one-pass yield to dichlorobenzyl is not high; the production cost caused by various reasons is high, etc.

Method used

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  • New process for preparing p-xylylene dichloride by adopting novel reaction equipment
  • New process for preparing p-xylylene dichloride by adopting novel reaction equipment

Examples

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Effect test

Embodiment 1

[0043] A novel reaction equipment for preparing p-dichlorobenzyl includes a reactor, a gas-liquid separator, a crystallizer, and an LED lamp;

[0044] The outside of the reactor is fixed with an LED lamp 4, and the reactor is sealed with a chlorine gas inlet pipe 5;

[0045] The reactors are divided into three groups, which are respectively a first-stage reactor 1, a second-stage reactor 2, and a third-stage reactor 3;

[0046] The gas-liquid separator is divided into two groups, which are gas-liquid separator one 6 and gas-liquid separator two 7;

[0047] The gas-liquid separator one 6 is arranged between the first-stage reactor 1 and the second-stage reactor 2, and the first-stage reactor 1 is sealed and connected through the material pipeline 8, and the second-stage reactor 2 is sealed through the reaction liquid pipeline 9; The gas-liquid separator 2 7 is arranged between the second-stage reactor 2 and the third-stage reactor 3, and is sealed and connected to the second-s...

Embodiment 2

[0059] A total of 1000G p-xylene and 1210G chlorine gas are continuously pumped into the chlorinator with a high-pressure pump, and the reaction is initiated by an LED lamp. After a period of chlorine reaction, the material enters the gas-liquid separator to complete the reaction liquid and the hydrogen chloride gas generated by the reaction. After the gas-liquid separation, a reaction solution and chlorine gas are passed into the second-stage reactor, so that chlorine is divided into three sections, and the final reaction solution is sampled and tested (Table 1). The conversion rate of p-xylene is 97.75%, and p-dichlorobenzyl And the total selectivity to benzyl chloride is 99.01%, wherein the content of benzyl chloride is 74.65%. The third section of chlorinated material enters the crystallizer, and after gas-liquid separation and crystallization, the final product is obtained by filtration and separation, and the product content reaches 99.62%.

Embodiment 3

[0061] A total of 1000G p-xylene and 1170G chlorine gas are continuously pumped into the chlorinator with a high-pressure pump, and the reaction is initiated by an LED lamp. After a period of chlorine reaction, the material enters the gas-liquid separator to complete the reaction liquid and the hydrogen chloride gas produced by the reaction. After the gas-liquid separation, a reaction solution and chlorine gas are passed into the second-stage reactor, so that chlorine is divided into three sections, and the final reaction solution is sampled and tested (Table 1). The conversion rate of p-xylene is 96.49%, and p-dichlorobenzyl And the total selectivity to benzyl chloride is 99.09%, wherein the content of benzyl chloride is 70.04%. The third stage of chlorinated material enters the crystallizer, and after gas-liquid separation and crystallization, the final product is obtained by filtration and separation, and the product content reaches 99.59%.

[0062] Substance name ...

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Abstract

The invention discloses a new process for preparing p-xylylene dichloride by adopting novel reaction equipment. The novel reaction equipment comprises a chlorinator, a gas-liquid separator, a crystallizer and the like. The process for preparing the p-xylylene dichloride by adopting the novel reaction equipment comprises the following steps: (1) reaction; and (2) separation by crystallization. Theprocess has the beneficial effects that by adopting the novel reaction equipment, p-xylene and chlorine gas can be thoroughly and uniformly mixed, and excessive chlorination caused by high local chlorine concentration is avoided; chlorination is carried out in three stages, a reactant proportioning ratio of each stage is accurately controlled, the single-pass conversion ratio of p-xylene is higherthan 96%, the total selectivity of p-xylylene dichloride and p-methyl benzyl chloride in a chlorination solution reaches up to 98%, and the content of p-xylylene dichloride reaches up to 70% or more;a used LED lamp, as a light source, for initiating reaction is proper in wavelength and is high in initiating efficiency, the reaction temperature can be greatly lowered, and side reactions can be effectively reduced; and the chlorination solution is low in impurity content, the product is not required to be purified by a vacuum rectification process, and the product with the content of 99% or more can be obtained by once simple crystallization.

Description

technical field [0001] The invention relates to a new process for preparing p-dichlorobenzyl by adopting novel reaction equipment. Background technique [0002] p-Dichlorobenzyl is an important chemical raw material, its appearance is white flaky crystal, as an intermediate of organic synthesis, it is mainly used in the manufacture of p-xylylenedimethanol, p-xylylene dimethyl ether, terephthalaldehyde and other dyes. Can be used as pharmaceutical intermediates. [0003] The preparation process of p-dichlorobenzyl mentioned in previous literatures has the following problems in varying degrees: low reaction selectivity, resulting in the generation of a large number of by-products; The content of benzyl is low, and the one-pass yield to dichlorobenzyl is not high; the production cost caused by various reasons is high. Contents of the invention [0004] The technical problem to be solved by the present invention is to provide a new process for preparing p-dichlorobenzyl by a...

Claims

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Application Information

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IPC IPC(8): C07C22/04C07C17/14C07C17/38
CPCC07C17/14C07C17/38C07C22/04
Inventor 况宗盛孙晓伟张相荣
Owner 青岛和兴精细化学有限公司
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