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Production method of para chlorotoluene

A technology of p-chlorotoluene and its production method, which is applied in the field of directional chlorination of toluene to produce high-purity p-chlorotoluene, which can solve the problems of limited industrialization prospects and achieve the effects of low production cost, obvious economic benefits, and high product quality

Active Publication Date: 2009-07-08
ZHEJIANG WEIHUA NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, there is little prospect of industrialization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] In a four-necked flask equipped with a condenser tube, a chlorine pipe, stirring, and a thermometer, add 350 g of newly prepared L-type zeolite molecular sieves, 3500 g (1 mol) of toluene and 130 g of 2-chloroethanol, start stirring, and heat the mixture to 50 ° C. Then feed chlorine gas at a rate of 2mol / hr, the reaction releases heat, the temperature of the feed liquid rises to 75°C, and the temperature of the feed liquid is controlled to be 75°C to 80°C when the chlorine is passed through. Chlorine and hydrogen chloride gas, cooling, filtration recovery catalyst, the catalyst is used for the next batch of chlorination reaction through regeneration and activation; the filtrate is mixed chlorotoluene, wherein p-chlorotoluene / o-chlorotoluene=4.16, polychlorinated compound 3.55%, m-chlorotoluene 0.86%, toluene conversion rate 98.32%.

[0025] Mixed chlorine toluene enters the toluene tower, recovers a small amount of unreacted toluene, and recycles the toluene for chlori...

Embodiment 2

[0028] Preparation of L-type zeolite molecular sieve:

[0029] press K 2 O:Al 2 o 3 : SiO 2 :H 2 The molar ratio of O was 8:1:12:300 to form a gel, and crystallized at 130°C for 5 hours to prepare a crystallization directing agent. Press K again 2 O:Al 2 o 3 : SiO 2 :H 2 The molar ratio of O is 4.2:1.0:10:160 to form a gel, add 5% by weight of crystallization directing agent, crystallize at 150°C for 19 hours, filter off the liquid, wash with water until pH = 10-10.5, and dry , and then baked at 540°C for 5 hours. Crushing, grinding, and sieving to make 100-mesh powdered L-type zeolite molecular sieve, and placing it in a closed container for later use. Before use, bake at 500°C for another 3 hours.

[0030] It can also be used as a molded catalyst, and the preparation method is as follows: silica sol (containing 30% SiO 2 ) and L-type zeolite in a weight ratio of 3:7 to form, dry and crush, screen the particles with a diameter of 0.1 mm to 0.3 mm, and roast at 5...

Embodiment 3

[0032] Chlorination reaction:

[0033]Add 8g L-type zeolite molecular sieves, 92.1g (1mol) toluene, and 3g chloroethanol in the reaction flask, heat the mixture to 70°C, and maintain this temperature, then feed chlorine gas at a rate of about 0.25mol / hr, after the reaction is completed , warming up and aeration, drive away chlorine and hydrogen chloride gas remaining in the reaction solution, lower the temperature, filter and recover the catalyst, p-chlorotoluene / o-chlorotoluene=3.25 in the filtrate, 7.6% of polychlorinated compounds, 0.9% of m-chlorotoluene, and 0.9% of toluene The conversion rate was 88.6%.

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Abstract

The present invention relates to a production method of high-purity p-chlorotoluene. Said method includes the following steps: using L-type zeolite molecular sieve as catalyst, using low-grade halogenated saturated alkanol or low-grade halogenated saturated fully acid or its potassium and sodium salt as cocatalyst, making toluene and chlorine gas be fully reacted, then aerating, removing chlorine gas and hydrogen chloride from reaction solution, rectifying to remove unreacted toluene and tolylchloride, then more adding L-type zeolite molecular sieve catalyst, continuously introducing chlorine gas to make reaction, after said reaction is completed, aerating, removing chlorine gas and hydrogen chloride, further making rectification and separation so as to obtain high-purity p-chloro to luene.

Description

technical field [0001] The invention relates to a production method of p-chlorotoluene, in particular to a production method of directional chlorination of toluene to produce high-purity p-chlorotoluene. Background technique [0002] P-chlorotoluene is an important organic chemical raw material, widely used in the manufacture of fine organic chemical products such as pesticides, medicines, and dyes. p-Chlorotoluene is produced by toluene cyclochlorination reaction, but using common Lewis acid as a catalyst, most of the monochlorotoluene obtained by toluene ring chlorination reaction is o-chlorotoluene, and p-chlorotoluene only accounts for 30% to 35%. . Since the use of p-chlorotoluene is far greater than that of o-chlorotoluene, it is necessary to select a suitable directional catalyst for ring chlorination to increase the proportion of p-chlorotoluene in the ring chlorination of toluene. The most common method is to use a Lewis acid catalyst At the same time, sulfur powd...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C17/12C07C25/02
Inventor 吴顺华
Owner ZHEJIANG WEIHUA NEW MATERIAL CO LTD
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