Method for preparing monochlorotoluene with toluene chloridizing method

A monochlorotoluene, ring chlorination technology, applied in the chemical field, can solve the problems of insufficient selectivity, reduce the total yield of p-chlorotoluene and o-chlorotoluene, and many by-products of m-chlorotoluene, and achieve the goal of improving selectivity Effect

Inactive Publication Date: 2012-10-24
常州新东化工发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above method has the following disadvantages. The one is that the selectivity of para-chlorotoluene is not high enough, and the highest p-chlorotoluene / ortho-chlorotoluene is only 1.66; The method is difficult to separate from p-chlorotoluene. To obtain high-purity p-chlorotoluene, it is necessary to feed excess chlorine gas to convert m-chlorotoluene into dichlorotoluene with a higher boiling point, and also make part of p-chlorotoluene and o-chlorotoluene Converted into dichlorotoluene to facilitate separation, thereby reducing the total yield of p-chlorotoluene and o-chlorotoluene

Method used

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  • Method for preparing monochlorotoluene with toluene chloridizing method
  • Method for preparing monochlorotoluene with toluene chloridizing method
  • Method for preparing monochlorotoluene with toluene chloridizing method

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Experimental program
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Effect test

Embodiment 1

[0018] Take by weighing 30g toluene, iron powder 20mg, auxiliary agent I (R 1 =NHOH) 10 mg, and evenly and slowly pass chlorine gas for 4 hours while stirring in the dark, and the temperature in the whole process is controlled at 0°C. After the reaction is completed, filter, wash with water, dry over anhydrous sodium sulfate, and filter. Sampling was carried out for gas chromatography detection. The toluene conversion rate was 97.2%, the content ratio of p-chlorotoluene and o-chlorotoluene was about 2.1, the content of m-chlorotoluene was 0.12%, and the content of total dichlorobenzene was 0.55%.

Embodiment 2

[0020] Take by weighing 30g toluene, iron powder 20mg, auxiliary agent II (R 2 = Cl) 25 mg, and evenly and slowly pass chlorine gas for 4 hours while stirring in the dark, and the temperature in the whole process is controlled at 20°C. After the reaction is completed, filter, wash with water, dry with anhydrous sodium sulfate, and filter. Sampling was carried out for gas chromatography detection, and the toluene conversion rate was 96.5%, the content ratio of p-chlorotoluene and o-chlorotoluene was about 1.8, the content of m-chlorotoluene was 0.10%, and the content of total dichlorotoluene was 0.72%.

Embodiment 3

[0022] Take by weighing 30g toluene, iron powder 20mg, auxiliary agent II (R 2 =NH 2 ) 25 mg, and stirred slowly in the dark for 4 hours, and the temperature of the whole process was controlled at 30 ° C. After the reaction was completed, filtered, washed with water, dried with anhydrous sodium sulfate, and filtered. Sampling was carried out for gas chromatography detection, and the toluene conversion rate was 98.0%, the content ratio of p-chlorotoluene and o-chlorotoluene was about 1.7, the content of m-chlorotoluene was 0.15%, and the content of total dichlorobenzene was 0.84%.

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Abstract

The invention provides a method for preparing monochlorotoluene with a toluene chloridizing method. The method comprises the following specific steps of: adding iron powder or iron chloride serving as a catalyst into a toluene liquid, adding an aid, introducing chorine gas under a light-shading situation, controlling the temperature of an entire chloridizing process at 0-30 DEG C, and controlling the chlorine-introducing amount to keep the transformation rate of toluene between 96 percent and 99 percent; and cooling, and filtering an ion liquid out to obtain a toluene mono-chlorinated mixed solution. After the aid and iron or iron chloride serving as a catalyst used in the method are mixed and applied to toluene chloridizing, the selectivity of a product on toluene chloride is effectively increased, the highest selectivity on chlorotoluene / o-chlorotoluene is up to 2.1, the selectivity on m-chlorotoluene is less than 0.15 percent, and the selectivity on total dichlorotoluene is less than 1.0 percent.

Description

technical field [0001] The invention belongs to the technical field of chemistry and relates to a method for preparing monochlorotoluene by a toluene ring chlorination method. Background technique [0002] Using chlorine gas as a chlorination agent to chlorinate toluene to co-produce o-chlorotoluene and p-chlorotoluene is a commonly used method in industry. Due to the low activity of toluene, the reaction usually needs to be catalyzed by adding a catalyst. [0003] When chlorine gas is used as the chlorination agent to carry out ring chlorination of toluene, Lewis acid is often used as a catalyst. 3 Or iron powder, but only when Lewis acid is used as catalyst for toluene ring chlorination, p-chlorotoluene / o-chlorotoluene is only 1:3. The para-selectivity can be improved by adding different sulfur-containing additives, including sulfur powder, sulfur monochloride, sulfur dichloride, mercaptan, mercapto aliphatic carboxylic acid, aliphatic thiocarboxylic acid, thioether, alky...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C25/02C07C17/12
Inventor 王明亮陶文平杨振伟顾留杰毛素华马健葛裕华
Owner 常州新东化工发展有限公司
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