Industrial synthesis method for 4-trifluoromethylphenylhydrazine Hydrochloride

A technology of trifluoromethylphenylhydrazine and trifluoromethylaniline, which is applied in the field of industrialized preparation of 4-trifluoromethylphenylhydrazine hydrochloride, can solve the problem that there is no effective industrial synthesis method for preparation, and the yield of literature operation is not high. High, there are safety hazards and other problems, to achieve the effect of low requirements, high overall yield and easy operation

Inactive Publication Date: 2008-07-02
上海药明康德新药开发有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] 4-trifluoromethylphenylhydrazine is an important commonly used drug intermediate, but so far there is no effective industrial synthesis method for preparing this product
[0008] 1. The reaction process requires high temperature and high pressure, and the risk factor is high in industrial production
[0009] 2. Although the selectivity of this reaction is better, the required time is relatively long. It is reported in the literature that when the reaction is terminated for 6 hours, the yield and conversion rate are only 20% to 30%.
[0014] 1. The use of acid gas reagents has potential safety hazards in factory operations
[0015] 2. The reaction yield is low, and the yield reported in the literature is only 43%
But the literature operation yield is not high, only 67%

Method used

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  • Industrial synthesis method for 4-trifluoromethylphenylhydrazine Hydrochloride
  • Industrial synthesis method for 4-trifluoromethylphenylhydrazine Hydrochloride

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Embodiment 1

[0029] Synthesis of 4-Trifluoromethylphenylhydrazine Hydrochloride

[0030] Under mechanical stirring, a 10-liter three-necked flask equipped with 20% hydrochloric acid aqueous solution (3.5 L) was cooled to 5-10 ° C with an ice bath, and 4-trifluoromethylaniline (500 g, 3.1 mol ). The dropwise addition process is accompanied by heat release, and the reaction solution slowly becomes a suspension. After the dropwise addition, lower the reaction solution to 0-5°C, add sodium nitrite aqueous solution (225g / 0.5L) dropwise to the suspension with a dropping funnel, control the internal temperature below 5°C during the dropping process, and add the time Control in 2 hours. It can be observed that the reaction solution turns into a clear and transparent solution. After stirring for half an hour at 0-5°C, add SnCl dropwise to the clear liquid 2 .2H 2 O (1.7kg, 13.3mol) of hydrochloric acid solution (35-37% HCl, 1.7L), during the dropwise addition, the internal temperature was co...

Embodiment 2

[0032] Synthesis of 4-Trifluoromethylphenylhydrazine Hydrochloride

[0033] Under mechanical stirring, a 10-liter three-neck flask containing 20% ​​hydrochloric acid aqueous solution (3.5 L) was cooled to 0-5 ° C with an ice bath, and 4-trifluoromethylaniline (500 g, 3.1 mol ). The dropwise addition process is accompanied by heat release, and the reaction solution slowly becomes a suspension. After the dropwise addition, lower the reaction solution to 0-5°C, add sodium nitrite aqueous solution (225g / 0.5L) dropwise to the suspension with a dropping funnel, control the internal temperature below 5°C during the dropwise addition, and add the The time is controlled at 2 hours. It can be observed that the reaction solution turns into a clear and transparent solution. After stirring for half an hour at 0-5°C, add SnCl dropwise to the clear liquid 2 .2H 2 O (1.7kg, 13.3mol) of hydrochloric acid solution (35-37% HCl, 1.7L), during the dropwise addition, the internal temperature...

Embodiment 3

[0035] Synthesis of 4-Trifluoromethylphenylhydrazine Hydrochloride

[0036] Under mechanical stirring, a 10-liter three-necked flask equipped with 20% hydrochloric acid aqueous solution (3.5 L) was cooled to 5-10 ° C with an ice bath, and 4-trifluoromethylaniline (500 g, 3.1 mol ). The dropwise addition process is accompanied by heat release, and the reaction solution slowly becomes a suspension. After the dropwise addition, adjust the reaction solution to 5-10°C, add sodium nitrite aqueous solution (225g / 0.5L) dropwise to the suspension with a dropping funnel, control the internal temperature below 5°C during the dropping process, and add the time Control in 2 hours. It can be observed that the reaction solution turns into a clear and transparent solution. After stirring for half an hour at 0-5°C, add SnCl dropwise to the clear liquid 2 .2H 2 O (1.7kg, 13.3mol) of hydrochloric acid solution (35-37% HCl, 1.7L), during the dropwise addition, the internal temperature was ...

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Abstract

The invention relates to a preparation method for composing aromatic hydrazine hydrochloride, in particular to an industrial preparation method of 4-trifluoromethyl phenylhydrazine hydrochlorid. The invention mainly aims at solving the technical problems that low yield of the existing synthetic methods has low yield and industrial production can not be realized. The invention takes 4-trifluoromethyl aniline as raw material, successive reactions 'in one pot' happen, diazotization and reduction are carried out successively, diazonium hydrochloride is prepared after diazo reaction of sodium nitrite in aqueous hydrochloric acid solution, then hydrochloric acid solution of reducer stannous chloride is used for achieving reduction reaction, finally, filtration and washing are carried out and the 4-trifluoromethyl phenylhydrazine hydrochlorid is prepared. The invention can be used for the industrial production of the 4-trifluoromethyl phenylhydrazine hydrochlorid, and the yield can be up to more than 75 percent.

Description

Technical field: [0001] The invention particularly relates to a preparation method for the synthesis of aromatic hydrazine hydrochloride, in particular to an industrial preparation method for 4-trifluoromethylphenylhydrazine hydrochloride. Background technique: [0002] 4-Trifluoromethylphenylhydrazine is an important commonly used drug intermediate, but so far there is no effective industrial synthesis method for preparing this product. [0003] For the preparation of 4-trifluoromethylphenylhydrazine, there are three representative methods reported in the literature. [0004] Method 1: Using 4-trifluoromethylchlorobenzene as the starting material, react with hydrazine hydrate in an autoclave at 180°C and 0.4MPa to generate 4-trifluoromethylphenylhydrazine (Ref: US6410737). As follows: [0005] Literature synthetic route 1: [0006] [0007] This synthetic route is not suitable for industrial scale batch production because: [0008] 1. The reaction process requires hi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C241/02C07C243/22
Inventor 刘崇刚周盛峰顾虹唐苏翰李革
Owner 上海药明康德新药开发有限公司
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