阅读说明：本技术 盐酸转位合成3,3’-二氯联苯胺盐酸盐的方法 (Method for synthesizing 3, 3' -dichlorobenzidine hydrochloride by hydrochloric acid transposition ) 是由 史乐萌 付春 黄伟 韦志强 郁铭 高留冕 于 2018-06-25 设计创作，主要内容包括：一种盐酸转位合成3,3’-二氯联苯胺盐酸盐的方法,包括以下步骤：(1)溶解：将2,2’-二氯氢化偶氮苯加入甲苯中,完全溶解；(2)转位反应：在上述溶液中加入助剂,在常温下缓慢滴加与溶液相同质量的31%盐酸。滴加完毕后升温,进行转位反应。反应一段时间后,对溶液中的2,2’-二氯氢化偶氮苯含量进行检测,当检测结果﹤0.5%时即终止转位反应；(3)后处理：将转位液加水溶解,分出下层水相后进行脱色、过滤,即得3,3’-二氯联苯胺盐酸盐成品。本发明操作简便,更易于实施,因此具备更好的应用前景。(A method for synthesizing 3, 3' -dichlorobenzidine hydrochloride by hydrochloric acid transposition comprises the following steps: (1) dissolving: adding 2, 2' -dichlorohydrazobenzene into toluene, and completely dissolving; (2) and (3) transposition reaction: adding an auxiliary agent into the solution, and slowly dropwise adding 31% hydrochloric acid with the same mass as the solution at normal temperature. After the dropwise addition, the temperature is raised, and the transposition reaction is carried out. After reacting for a period of time, detecting the content of 2, 2' -dichlorohydrazobenzene in the solution, and stopping the transposition reaction when the detection result is less than 0.5%; (3) and (3) post-treatment: dissolving the transposition liquid in water, separating the lower water phase, decoloring and filtering to obtain the finished product of the 3, 3' -dichlorobenzidine hydrochloride. The method is simple and convenient to operate and easy to implement, and therefore has a better application prospect.)

1. A method for synthesizing 3, 3' -dichlorobenzidine hydrochloride by hydrochloric acid transposition is characterized in that the synthesis process comprises the following steps:

(1) dissolving: adding 2, 2' -dichlorohydrazobenzene into toluene, and completely dissolving;

(2) and (3) transposition reaction: adding an auxiliary agent into the solution, slowly dropwise adding 31% hydrochloric acid with the same mass as the solution at normal temperature, heating after dropwise adding, carrying out transposition reaction, detecting the content of 2, 2' -dichlorohydrazobenzene in the solution after reacting for a period of time, and stopping the transposition reaction when the detection result is less than 0.5%;

(3) and (3) post-treatment: dissolving the transposition liquid in water, separating the lower water phase, decoloring and filtering to obtain the finished product of the 3, 3' -dichlorobenzidine hydrochloride.

2. The method according to claim 1, wherein in the dissolving step, the mass ratio of 2, 2' -dichlorohydrazobenzene to toluene is 1: 0.9 ~ 1.2.2.

3. The method according to claim 1, wherein in the step of translocation reaction, the additive is TX series emulsifier; one or two of sodium dodecyl benzene sulfonate, sodium dodecyl sulfonate and hexadecyl trimethyl ammonium bromide.

4. The method according to claim 1, wherein in the step of transposition reaction, the mass ratio of the auxiliary agent to the 2, 2' -dichlorohydrazobenzene is 1: 125-200.

5. The method according to claim 3, wherein in the translocation reaction step, the mass ratio of one or two of sodium dodecylbenzene sulfonate, sodium dodecylbenzene sulfonate and hexadecyl trimethyl ammonium bromide to the TX series emulsifier is 1: 4 to 5.

6. The method according to claim 1, wherein the time for dropping hydrochloric acid in the translocation reaction step is 1.5 to 2.5 hours.

7. The method according to claim 1, wherein the transposition reaction step comprises heating to 40-50 ℃ after the hydrochloric acid is added dropwise to perform the transposition reaction.

Technical Field

The invention relates to a method for synthesizing 3, 3' -dichlorobenzidine hydrochloride by hydrochloric acid transposition, belonging to the technical field of chemical industry.

Background

3, 3' -dichlorobenzidine, DCB for short, is an important intermediate for producing organic pigments of the dichlorobenzidine series, and the yield of series of organic pigments mainly manufactured by the intermediate accounts for about 25 percent of the total amount of the organic pigments, so the intermediate is widely applied to the production of coloring slurry and pigment dyeing slurry of coloring and pigment printing slurry such as printing ink, paint, rubber, plastic and the like. The commercial product is generally in the form of a hydrochloride salt having the formula:

at present, the transposition process of 3, 3' -dichlorobenzidine hydrochloride has two kinds of transposition processes of sulfuric acid and hydrochloric acid. The transposition of sulfuric acid has the advantages of fast reaction, standing for layering and easy further purification, but the process is more complicated because the solubility of the sulfate of the 3, 3' -dichlorobenzidine is high and the sulfate is converted into hydrochloride after rearrangement, and the generated waste sulfuric acid is required to be treated, so that the treatment difficulty of three wastes is high and the cost is high. Many patents, such as CN101372381A, CN1752032A, and CN1629131A, are all dedicated to the research on recycling of waste sulfuric acid in the sulfuric acid transposition process.

Compared with the prior art, the hydrochloric acid transposition process is simple, easy to operate and high in yield, waste acid needing to be recovered is not generated in the reaction process, and the three-waste treatment cost and pressure are obviously reduced, so that the hydrochloric acid transposition process has a better development prospect, but the hydrochloric acid transposition process also has the defects of viscous materials, large mass transfer resistance, slow reaction and the like, and the high yield can be achieved only by long reaction time.

Patent CN1861568A reports a technical scheme for preparing 3, 3' -dichlorobenzidine hydrochloride, which is a hydrochloric acid transposition process. The technical scheme has the advantages of low reaction system viscosity, short reaction time, high product yield and the like, but the method can be realized only by adding high-concentration hydrochloric acid, adopting a special reactor to improve a stirring mode and pre-cooling a hydrochloric acid solution and a 2, 2' -dichlorohydrazobenzene aromatic hydrocarbon solution, so that the application prospect is limited.

Disclosure of Invention

The invention aims to provide a method for synthesizing 3, 3' -dichlorobenzidine hydrochloride by hydrochloric acid transposition. Aiming at the defects of the existing technology for synthesizing 3, 3' -dichlorobenzidine hydrochloride by hydrochloric acid transposition, the defects of viscous material, large mass transfer resistance, slow reaction and the like in the hydrochloric acid transposition reaction can be solved by adding an auxiliary agent in the transposition reaction, a special reactor is not needed, hydrochloric acid is dripped at normal temperature, and the raw material is not needed to be pre-cooled.

The invention is carried out according to the following steps:

(1) dissolving: adding 2, 2' -dichlorohydrazobenzene into toluene, and completely dissolving;

(2) and (3) transposition reaction: adding an auxiliary agent into the solution, and slowly dropwise adding 31% hydrochloric acid with the same mass as the solution at normal temperature. After the dropwise addition, the temperature is raised, and the transposition reaction is carried out. After reacting for a period of time, detecting the content of 2, 2' -dichlorohydrazobenzene in the solution, and stopping the transposition reaction when the detection result is less than 0.5%;

(3) and (3) post-treatment: dissolving the transposition liquid in water, separating the lower water phase, decoloring and filtering to obtain the finished product of the 3, 3' -dichlorobenzidine hydrochloride.

In the step (1), the mass ratio of the 2, 2' -dichlorohydrazobenzene to the toluene is 1: 0.9 ~ 1.2.2.

In the step (2), the added auxiliary agent is one or two of TX series emulsifier, sodium dodecyl benzene sulfonate, sodium dodecyl sulfonate and hexadecyl trimethyl ammonium bromide.

In the step (2), the mass ratio of the auxiliary agent to the 2, 2' -dichlorohydrazobenzene is 1: 125-200.

In the step (2), the mass ratio of the two added auxiliary agents is 1: 4 to 5.

In the step (2), the hydrochloric acid is dripped for 1.5-2.5 h.

In the step (2), after the hydrochloric acid is dripped, the temperature is raised to 40-50 ℃ for transposition reaction.

The invention has the advantages that: (1) compared with the sulfuric acid transposition process, the invention adopts the hydrochloric acid transposition method, does not generate waste acid, obviously reduces the treatment difficulty of three wastes and has higher product yield; (2) compared with the traditional hydrochloric acid transposition process, the invention has the advantages that the addition agent is added in the transposition reaction, so that the viscosity of the reaction system is obviously reduced, the reaction system is improved, the reactants are fully contacted, and the reaction rate is greatly accelerated; (3) compared with the prior patent, the invention reduces the viscosity of the material by adding the auxiliary agent, and the prior patent realizes the purposes of improving the reactor, pre-cooling the reactant and the like. Compared with the prior art, the method is simple and convenient to operate and easy to implement, and therefore has a better application prospect.

Detailed Description