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Method for producing parachlorotoluene through continuous chlorination of methylbenzene

A technology for p-chlorotoluene and chlorinated products, applied in chemical instruments and methods, chemical recovery, organic chemistry, etc., can solve the problems of shortened service life, reduced para-selectivity of cyclic chlorination, and restrictions, and reduced production costs. , the effect of reducing solid waste emissions

Inactive Publication Date: 2018-08-31
江苏优普生物化学科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In recent years, there have been many reports on the synthesis, improvement and application of L-type zeolite, and the research is very active. It is reported that using L-type zeolite for toluene chlorination can obtain very ideal para-selectivity. The mass fraction of p-chlorotoluene Generally 70~90%, the selectivity of p-chlorotoluene is extremely high, which is a promising synthetic technology, but the hydrogen chloride generated in the reaction is easy to damage the zeolite lattice, which reduces the para-selectivity of ring chlorination and shortens the service life. shortening, catalyst regeneration is difficult, and the polychlorinated toluene content is high, resulting in high production costs and limited applications

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Molecular sieve preparation: Add 3060 kg (170 mol) of distilled water to a 5000L autoclave, start stirring, add 583 kg (96%, 9.99 mol) of potassium hydroxide, 1108 kg (92%, 16.99 mol) of white carbon black, and press Fix the lid of the kettle, heat it to 100~130℃, keep it warm for 1~3 hours, and make potassium silicate; add distilled water, potassium hydroxide, sodium hydroxide, white carbon black, distilled water, potassium hydroxide, The molar ratio of sodium hydroxide to white carbon black is 15~30:1:0.1~0.3:1.3~2.5, heated to 10~130°C and kept for 1~3 hours to make potassium sodium water glass; distilled water: potassium hydroxide : Aluminum hydroxide is added to the reaction kettle at a molar ratio of 5~12:1:0.1~0.5, and kept at 60~80°C for 2~3 hours to make a potassium metaaluminate solution. Put potassium water glass, potassium sodium water glass, potassium metaaluminate, and distilled water into the autoclave in a weight ratio of 1:1:2:1~3, stir vigorously for 2...

Embodiment 2

[0022] Put the catalyst obtained in Example 1 into two φ50×1000mm packed columns respectively to make fixed beds A and B, heat the toluene to 60~70°C, pump it in from the bottom of fixed bed A at a flow rate of 50~70g / h, and simultaneously 35~50g / h chlorine gas is fed from the bottom. The temperature in the bed is controlled at 70-80°C. After the chlorinated liquid coming out from the top is neutralized with soda ash, gas spectrum detection shows that toluene is 7.9%, p-chlorotoluene is 77.3%, o-chlorotoluene is 14.4%, and m-chlorotoluene is 0.1%. The conversion rate of toluene is 90.7%, and the para-ortho ratio is 5.37.

Embodiment 3

[0024] After the fixed bed A described in Example 2 was chlorinated for 90 hours, gas spectrometry detected the chlorinated liquid coming out of the top, toluene 11.4%, p-chlorotoluene 47.9%, ortho-chlorotoluene 40.3%, m-chlorotoluene 0.2%. The conversion rate of toluene is 85.2%, and the para-ortho ratio is 1.19. Switch the toluene and chlorine to the fixed bed B, and the fixed bed A discharges the toluene chlorinated liquid, blows and replaces it with nitrogen, gradually increases the temperature of the nitrogen to 60~70°C, and then pours potassium sodium water glass and metaaluminate from the bottom of the fixed bed Potassium solution is mixed at a mass ratio of 1:0.5~1.5 and pumped in circulation, the total amount is 800ml, the temperature is 60~100°C, and the temperature is kept for 12~48h. After the heat preservation is completed, the mixed liquid is drained, and nitrogen is purged from the bottom, and the nitrogen temperature is gradually increased to 150-200 ° C, and t...

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Abstract

The invention discloses a method for producing parachlorotoluene through continuous chlorination of methylbenzene. The method comprises the following steps: with an active molecular sieve as a catalyst, performing continuous chlorination on methylbenzene in a static bed, wherein a ratio of parachlorotoluene to o-chlorotoluene in the chlorination products is 1.2-6.0; performing aeration and distillation separation on the chlorination product to obtain high-purity parachlorotoluene, and enabling the separated methylbenzene and raw material methylbenzene to enter the static bed together so as toperform continuous chlorination; periodically reproducing the catalyst in the static bed; and alternately using and activating two groups or more than two groups of static beds. According to the method disclosed by the invention, continuous chlorination production of methylbenzene is realized, the ratio of parachlorotoluene to o-chlorotoluene is 1.2-6.0, the catalyst can be repeatedly used, the production cost is reduced, and solid waste emission is reduced.

Description

technical field [0001] The present invention relates to a kind of method of producing p-chlorotoluene. Background technique [0002] Chlorotoluene is an important chemical raw material and intermediate, which can be used as a raw material to prepare a variety of industrial products, mainly involving pesticides, medicines, dyes, new materials, etc. Chlorotoluene has three isomers: p-chlorotoluene, o-chlorotoluene, and m-chlorotoluene, among which p-chlorotoluene has been developed and used most widely. According to relevant information, in recent years, more than 100 kinds of pesticides, medicines, dyes, etc. have been derived from p-chlorotoluene. Esters, enolazole, oxacarb, Huwei, Guoer, etc., and pharmaceuticals such as fenalu, pyrimethamine, chlortrimidone, etc. The early production method is to diazotize p-methylaniline to generate diazonium salt, and then obtain p-chlorotoluene under the catalysis of cuprous chloride. This method has serious pollution and backward tec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/12C07C17/383C07C25/02
CPCC07C17/12C07C17/383C07C25/02Y02P20/584
Inventor 谢斌于海军邱历张继钱
Owner 江苏优普生物化学科技股份有限公司
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