Method used for producing 3,3'-dichlorobenzidine dihydrochloride from white oil instead of toluene

A technology of dichlorobenzidine hydrochloride and dichlorohydroazobenzene, which is applied in the field of dyes, can solve the problems of toxicity, large toluene volatilization, occupational diseases, etc., and achieve the effects of simple process flow, reduced pollution and high quality

Inactive Publication Date: 2018-10-09
SHANDONG XINHUA LONGXIN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, both methods will inevitably use a large amount of toluene as a solvent. Because there is a precious metal catalyst in the catalytic hydrogenation reaction, the catalyst must be recovered and reused. A large amount of toluene will inevitably volatilize during recovery, and there is a relatively large problem in the subsequent treatment process. Toluene volatilization
Toluene is poisonous, prone to static electricity, low flash point, not environmentally friendly, and likely to cause occupational diseases to the human body

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The invention provides a technical solution: a method for producing 3,3′-dichlorobenzidine hydrochloride by replacing toluene with white oil, which comprises the following steps:

[0025] S1: Reduction reaction, put o-nitrochlorobenzene, white oil, sodium hydroxide, water, catalyst, co-catalyst and surfactant into the high-pressure reactor, start stirring, control the stirring speed to 160rpm, and continue the reaction for 5 hours, Filter the material in the high-pressure reactor, recover the catalyst from the filter cake for use, and obtain a mixture of 2,2'-dichlorohydroazobenzene and white oil from the filtrate;

[0026] S2: Transposition rearrangement, cool the mixture of 2,2'-dichlorohydroazobenzene and white oil to 40°C to obtain 2,2'-dichlorohydroazobenzene crystals, then filter, return the filtrate for reduction, Use a grinder to grind 2,2′-dichlorohydroazobenzene until the particle size is 60 mesh, send it into 23% hydrochloric acid for transposition rearrangem...

Embodiment 2

[0033] The invention provides a technical solution: a method for producing 3,3′-dichlorobenzidine hydrochloride by replacing toluene with white oil, which comprises the following steps:

[0034] S1: Reduction reaction, put o-nitrochlorobenzene, white oil, sodium hydroxide, water, catalyst, co-catalyst and surfactant into the high-pressure reactor, start stirring, control the stirring speed to 180rpm, and continue the reaction for 6 hours, Filter the material in the high-pressure reactor, recover the catalyst from the filter cake for use, and obtain a mixture of 2,2'-dichlorohydroazobenzene and white oil from the filtrate;

[0035] S2: Transposition rearrangement, cool the mixture of 2,2'-dichlorohydroazobenzene and white oil to 35°C to obtain 2,2'-dichlorohydroazobenzene crystals, then filter, and return the filtrate for reduction. Use a grinder to grind 2,2′-dichlorohydroazobenzene to a particle size of 60 mesh, send it into 23% hydrochloric acid for transposition rearrangeme...

Embodiment 3

[0042] The invention provides a technical solution: a method for producing 3,3′-dichlorobenzidine hydrochloride by replacing toluene with white oil, which comprises the following steps:

[0043]S1: Reduction reaction, put o-nitrochlorobenzene, white oil, sodium hydroxide, water, catalyst, co-catalyst and surfactant into the high-pressure reactor, start stirring, control the stirring speed to 200rpm, and continue the reaction for 7 hours, Filter the material in the high-pressure reactor, recover the catalyst from the filter cake for use, and obtain a mixture of 2,2'-dichlorohydroazobenzene and white oil from the filtrate;

[0044] S2: Transposition rearrangement, cool the mixture of 2,2'-dichlorohydroazobenzene and white oil to 30°C to obtain 2,2'-dichlorohydroazobenzene crystals, then filter, and return the filtrate for reduction. Use a grinder to grind 2,2'-dichlorohydroazobenzene to a particle size of 60 mesh, send it into 23% hydrochloric acid for transposition rearrangemen...

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Abstract

The invention discloses a method used for producing 3,3'-dichlorobenzidine dihydrochloride from white oil instead of toluene, and belongs to the technical field of dye. The method comprises followingsteps: 1, reduction reaction; 2, transposition rearrangement; 3, purification; 4, decoloring; 5, cooling crystallization; and 6, centrifugation. The method is scientific and reasonable; the technicalprocess is simple; white oil is adopted to replace toluene as a solvent in ortho-nitrochlorobenzene catalytic hydrogenation, white oil is colorless, odourless, and nontoxic, so that safety and environment protection hidden troubles caused by using of toluene are avoided; pollution is reduced greatly; the method is extremely friendly to the environment, is a clean production technology; after transposition reaction, separation of 3,3'-dichlorobenzidine dihydrochloride with white oil can be realized easily; product yield is high; and quality is high.

Description

technical field [0001] The invention relates to the technical field of dyes, in particular to a method for producing 3,3'-dichlorobenzidine hydrochloride by replacing toluene with white oil. Background technique [0002] 3,3′-Dichlorobenzidine hydrochloride (C12H10Cl2N2 2HCl) is an important intermediate in the production of dichlorobenzidine series organic pigments, and the output of organic pigments prepared with it as the main raw material accounts for about 27%, widely used in ink, paint, rubber, plastic and other coloring and pigment printing paste and pigment dyeing paste production. [0003] Now domestically and internationally, two catalytic reduction methods are used to prepare 3,3′-dichlorobenzidine hydrochloride. These two methods are based on the catalytic hydrogenation method. The difference is that one is transposition with hydrochloric acid. Reaction, one is transposition reaction with sulfuric acid + hydrochloric acid. However, both methods will inevitably ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/56C07C209/54C07C209/84C07C245/08
CPCC07C209/54C07C209/84C07C245/08C07C211/56Y02P20/584
Inventor 韩志强于永坤庞建伟崔成武
Owner SHANDONG XINHUA LONGXIN CHEM
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