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Tech. of preparing 3,3-dichlorobenzidine hydrochloride

A dichlorobenzidine hydrochloride and process technology, applied in the chemical industry, can solve the problems of selectivity of transposition products, uneven mixing, and complicated processes that affect the conversion rate of transposition, achieve low cost, reduce heat transfer, good selectivity

Inactive Publication Date: 2006-11-15
CHANGZHOU JIASEN CHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The transposition reaction of sulfuric acid has fast reaction, and the organic phase can be removed by static layering, which is easy to be further purified. However, due to the high solubility of 3'3-dichlorobenzidine sulfate, it will be converted into hydrochloride after transposition, and the process is very difficult. Complicated; and the hydrochloride transposition reaction is simple and easy to operate compared with the sulfate transposition reaction, but in the transposition process of 2,2'-dichlorohydroazobenzene (abbreviated as DHB), due to the generated 3, 3'-Dichlorobenzidine hydrochloride is poorly soluble in benzene, toluene and xylene, etc., and slightly soluble in high-concentration hydrochloric acid and water. Therefore, after the reaction reaches a certain level, the viscosity of the reaction solution is too high, accompanied by crystallization. This situation directly leads to difficulty in stirring and serious uneven mixing, which affects the conversion rate of transposition and the selectivity of transposition products.

Method used

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  • Tech. of preparing 3,3-dichlorobenzidine hydrochloride

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Embodiment 1

[0025] A kind of preparation 3,3'-dichlorobenzidine hydrochloride technique, described process step is as follows:

[0026] (1). Mixing and cooling, the aromatic hydrocarbon toluene solvent of 2,2'-dichlorohydroazobenzene is mixed into 2,2'-dichlorohydroazobenzene toluene solution, then cooled to 10°C±2°C.

[0027] (2). Transposition reaction, 2,2'-dichlorohydroazobenzenetoluene solution is slowly all added dropwise to 1000 liters of hydrochloric acid solution in the cooled propulsion type transposition reactor to carry out transposition reaction, 2, The volume ratio of 2'-dichlorohydroazobenzene to the added hydrochloric acid solution is 1:1.2, the concentration of the added hydrochloric acid solution is 35%, the temperature is 10°C±2°C, and the temperature is kept at 10°C during the transposition reaction ±5°C, continue to stir for 1.5h, keep the temperature at 10±5°C, make the transposition reaction between 2,2'-dichlorohydroazobenzene and hydrochloric acid, the total opera...

Embodiment 2

[0032] A kind of preparation 3,3'-dichlorobenzidine hydrochloride technique, described process step is as follows:

[0033] (1). Mixing and cooling, the aromatic hydrocarbon toluene solvent of 2,2'-dichlorohydroazobenzene is mixed into 2,2'-dichlorohydroazobenzene toluene solution, then cooled to 10°C±2°C.

[0034] (2).Transposition reaction, 2,2'-dichlorohydroazobenzenetoluene solution is slowly added dropwise to 800 liters of hydrochloric acid solution in the cooled propulsion type transposition reactor, and the temperature is maintained in the process of adding. 10°C±5°C, after adding 2,2'-dichlorohydroazobenzene toluene solution, continue to add 200 liters of hydrochloric acid to the reaction system and continue stirring for 1.5h, 2,2'-dichlorohydroazobenzene and hydrochloric acid The volume ratio of the solution is 1: 1.2, the concentration of the added hydrochloric acid solution is 35%, and the temperature is kept at 10 ± 5°C to make 2,2'-dichlorohydroazobenzene and hydr...

Embodiment 3

[0039] A kind of preparation 3,3'-dichlorobenzidine hydrochloride technique, described process step is as follows:

[0040] (1). Mixing and cooling, the aromatic hydrocarbon toluene solvent of 2,2'-dichlorohydroazobenzene is mixed into 2,2'-dichlorohydroazobenzene toluene solution, then cooled to 10°C±2°C.

[0041] (2).Transposition reaction, 2,2'-dichlorohydroazobenzenetoluene solution is slowly added dropwise to 640 liters of hydrochloric acid solution in the cooled propulsion type transposition reactor, and the temperature is maintained in the process of adding. 10°C±5°C, after adding 2,2'-dichlorohydroazobenzene toluene solution, continue to add 200 liters of hydrochloric acid to the reaction system and continue stirring for 1.5h, 2,2'-dichlorohydroazobenzene and hydrochloric acid The volume ratio of the solution is 1: 1.0, the concentration of the added hydrochloric acid solution is 35%, and the temperature is maintained at 10±5° C., so that 2,2'-dichlorohydroazobenzene a...

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Abstract

A process for preparing 3,3'-dichlorobiphenylamine hydrochloride includes such steps as mixing 2,2'-azobenzene dichlorohydride with arylhydrocarbon solvent, cooling, adding the solution to cooled solution of hydrochloric acid, translocation reaction, mixing the resultant with water or dilute solution of hydrochloric acid, washing, liquid-liquid separation to obtain lower-layer water phase 3,3'-dichlorobiphenylamine hydrochloride and upper-layer oil phase arylhydrocarbon solution, separating said water phase and refining.

Description

technical field [0001] The invention relates to a transposition reaction process, in particular to a process for preparing 3,3'-dichlorobenzidine hydrochloride, which belongs to the technical field of chemical industry. Background technique [0002] 3'3-dichlorobenzidine (DCB) hydrochloride (C 12 h 10 Cl 2 N 2 2HCl), slightly soluble in water, soluble in alcohol, easy to oxidize, relatively stable in dilute hydrochloric acid solution, is an important pigment and dye intermediate, and benzidine yellow and urkangjian produced by this intermediate Fast red and azo dyes are better in acid resistance than those produced with benzidine, fast and green in color. The series of organic pigments made with it as the main body account for about 27% of the total organic pigments. In addition, it can also prepare direct dyes with excellent performance. At present, the common transposition reactions of 3,3'-dichlorobenzidine hydrochloride include sulfuric acid transposition reaction a...

Claims

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Application Information

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IPC IPC(8): C07C211/56C07C209/54
Inventor 许文林段玉辉刘学谦
Owner CHANGZHOU JIASEN CHEM
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