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Method for selectively preparing o-chlorotoluene

An o-chlorotoluene and selectivity technology, which is applied in the field of selective preparation of o-chlorotoluene, can solve the problems of difficult separation, complicated catalyst preparation, insufficient ortho-chlorination selectivity, etc., and achieves the effect of improving the selectivity.

Active Publication Date: 2022-01-07
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

Patents [US4647709, US 5105036, US5621153] etc. have reported the method for adjusting the content of o-chlorotoluene and p-chlorotoluene after adding different auxiliary catalysts. The above-mentioned method has the following disadvantages. %, the mass ratio of o-chlorotoluene and o-chlorotoluene is only 1.48
The second is that there are many by-products of m-chlorotoluene, and the rectification method currently used for m-chlorotoluene is difficult to separate from p-chlorotoluene
The content of p-chlorotoluene reported in this patent is more after toluene is chlorinated. The selectivity of this combined catalyst to o-chlorotoluene is not high, and the preparation of the catalyst is complicated, and the industrial cost is relatively large.

Method used

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  • Method for selectively preparing o-chlorotoluene
  • Method for selectively preparing o-chlorotoluene
  • Method for selectively preparing o-chlorotoluene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Add 30 mg of iron powder and 30 mg of 4-iododibenzothiophene (0.1% of the mass of toluene) into 30 ml of toluene, and under the condition of avoiding light and 35 ° C, uniformly and slowly pass in chlorine gas for about 7 hours, and take samples during the reaction. Gas chromatography detection. After the chlorination is finished, the toluene monochlorination mixed liquid component detection result is as follows: the transformation rate of toluene 99.81%, o-chlorotoluene content 68.50%, p-chlorotoluene content 30.08%, meta-chlorotoluene content 0.05%, the sum of polychlorinated toluene content was 1.18%.

Embodiment 2

[0033] 30 mg of iron powder and 15 mg of 1-bromodibenzothiophene (0.05% of the total mass of toluene) were added to 30 ml of toluene, and under the condition of avoiding light and 30°C, chlorine gas was uniformly and slowly introduced for about 8 hours, and samples were taken during the reaction. Gas chromatography detection. After the chlorination finishes, the toluene monochlorination mixed liquid component detection result is as follows: the conversion rate of toluene 99.28%, o-chlorotoluene content 63.69%, p-chlorotoluene content 33.30%, meta-chlorotoluene content 0.08%, the sum of polychlorinated toluene content was 2.21%.

Embodiment 3

[0035] 30mg of iron powder and 30mg of 2-bromodibenzothiophene (0.1% of the total mass of toluene) were added to 30ml of toluene, under the condition of avoiding light and 30°C, chlorine gas was evenly and slowly passed in for about 8 hours, and samples were taken during the reaction. Gas chromatography detection. After the chlorination finishes, the toluene monochlorination mixed liquid component detection result is as follows: the conversion rate of toluene 99.63%, o-chlorotoluene content 58.29%, p-chlorotoluene content 40.05%, meta-chlorotoluene content 0.15%, the sum of polychlorinated toluene content was 1.14%.

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Abstract

The invention discloses a method for selectively preparing o-chlorotoluene, which is characterized in that a mixture of iron powder and a dibenzothiophene compound is used as a combined catalyst, and chlorine is introduced into toluene under a dark condition to obtain o-chlorotoluene. The temperature in the chlorination process is controlled to be 30-50 DEG C, and the conversion rate of toluene is 98-100% by controlling the chlorine introduction amount. The chlorination liquid obtained after the catalyst is applied to toluene chlorination takes o-chlorotoluene as a main product, the percentage content of o-chlorotoluene is effectively increased, the highest content of o-chlorotoluene reaches 68.50%, the content of m-chlorotoluene is smaller than 0.15%, the content of total dichlorotoluene is smaller than 2.21%, and the mass ratio of o-chlorotoluene to p-chlorotoluene reaches 2.28.

Description

technical field [0001] The invention relates to a method for selectively preparing o-chlorotoluene, which belongs to the technical field of chemical synthesis. Background technique [0002] Ortho-chlorotoluene (OCT) is an important raw material intermediate, widely used as fine chemical intermediates such as pesticides, dyes and pharmaceuticals. Use o-chlorotoluene as raw material to synthesize o-chlorobenzoic acid series derivatives. It is used in the pharmaceutical industry to synthesize perphenazine. In the pesticide industry, it is mainly used to synthesize the insecticide diflubenzuron and the herbicide cyclafen. In the dye industry It is mainly used in the synthesis of dye disperse brilliant blue S-FR. [0003] In industry, toluene is generally used as raw material, chlorine gas is used as chlorine source, iron powder or ferric chloride and other Lewis acids are used as catalysts to co-produce o-chlorotoluene and p-chlorotoluene, and the chlorination reaction mixture ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/12C07C25/02
CPCC07C17/12C07C25/02
Inventor 年立春王明亮倪佳伟金海峰朱啸庆
Owner 常州新东化工发展有限公司
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