Synthesis method of para-trifluoromethyl phenyl hydrazine hydrochloride

A technology of trifluoromethylphenylhydrazine and trifluoromethylaniline, which is applied in the field of reduction chemical reaction and diazotization, and can solve the problem of poor control of the input amount, inconvenient and troublesome operation, toxicity of stannous chloride Large and other problems, to achieve the effect of low production cost, easy to scale up, and low toxicity

Inactive Publication Date: 2010-07-21
大连凯飞精细化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] 1) SO 2 Reduction with ammonia water (Tetrahedron, 1960, Vol.8, pp.67 to 72.), the disadvantage is that it is troublesome to feed the gaseous sulfur dioxide, and the amount of feeding is not easy to control
[0004] 2) reduction of stannous chloride and concentrated hydrochloric acid (J.Org.Chem.1995, 60, 2411-2422), its disadvantage is that stannous chloride is relatively toxic, inconvenient and troublesome to operate
[0005] There is no simple and effective method reported so far

Method used

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  • Synthesis method of para-trifluoromethyl phenyl hydrazine hydrochloride

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] 1. Preparation of diazo compound:

[0027] (1) Add 36ml of concentrated hydrochloric acid and 12ml of water into a four-necked bottle with a mechanical stirrer, a thermometer, and an addition funnel, and start stirring.

[0028] (2) p-Trifluoromethylaniline (8.0 g, 0.05 mol) was added dropwise into the reaction flask to form a large amount of white solid, exothermic, and continued stirring to form a paste, the temperature was controlled at 0-10°C.

[0029] (3) Cool the reaction solution to -5°C, add dropwise sodium nitrite solution (prepared from 10.3 grams of sodium nitrite and 20.1 grams of water), and control the temperature at -5 to 0°C. Stir at ~0°C for 2h.

[0030] (4) Add 10 wt% sodium carbonate solution dropwise to adjust the pH value of the diazotization reaction solution to 6-7.

[0031] 2. Reduction reaction:

[0032] (1) Add 125 milliliters of the prepared 25% sodium sulfite solution into a four-necked bottle with a mechanical stirrer, a thermometer and a...

Embodiment 2

[0037] 1. Preparation of diazo compound:

[0038] (1) Add 29ml of concentrated hydrochloric acid and 6.5ml of water into a four-necked bottle with a mechanical stirrer, a thermometer, and an addition funnel, and start stirring.

[0039] (2) p-Trifluoromethylaniline (8.0 g, 0.05 mol) was added dropwise into the reaction flask to generate a large amount of white solid, exothermic, and continued stirring to form a paste with the temperature controlled at 5-10°C.

[0040] (3) Cool the reaction solution to 0°C, add sodium nitrite solution (6.9 grams of sodium nitrite and 12.2 grams of water) dropwise, and control the temperature at 0-5°C. Stir for 1.5h.

[0041] (4) Add 12wt% sodium carbonate solution dropwise to adjust the pH value of the diazotization reaction solution to 5-6.

[0042] 2. Reduction reaction:

[0043] (1) Add 115 ml of prepared 22% sodium sulfite solution into a four-necked bottle with a mechanical stirrer, a thermometer, and an addition funnel, start stirring,...

Embodiment 3

[0048] 1. Preparation of diazo compound:

[0049] (1) Add 15ml of concentrated hydrochloric acid and 5.6ml of water into a four-necked bottle with a mechanical stirrer, a thermometer, and an addition funnel, and start stirring.

[0050] (2) p-Trifluoromethylaniline (8.2 g, 0.051 mol) was added dropwise into the reaction flask to form a large amount of white solid, exothermic, and continued stirring to form a paste, the temperature was controlled at 10-15°C.

[0051] (3) Cool the reaction solution to 5°C, add sodium nitrite solution (5.27 grams of sodium nitrite and 12.3 grams of water) dropwise, and control the temperature at 5-10°C. Stir for 1h.

[0052] (4) Add 11wt% sodium carbonate solution dropwise to adjust the pH value of the diazotization reaction solution to 5-6.

[0053] 2. Reduction reaction:

[0054] (1) Add 77 milliliters of the prepared 25% sodium sulfite solution into a four-necked bottle with a mechanical stirrer, a thermometer and an addition funnel, start ...

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Abstract

The invention relates to a synthesis method of para-trifluoromethyl phenyl hydrazine hydrochloride, which comprises the following steps: firstly leading para-trifluoromethylaniline and sodium nitrite to carry out diazotization reaction: adding concentrated hydrochloric acid and water into a four-neck flask, and starting stirring; dripping the para-trifluoromethylaniline, generating a larger number of white solids, and controlling the temperature at -5 DEG C-15 DEG C; reducing the temperature to -5 DEG C-5 DEG C, dripping sodium nitrite solution, controlling the temperature at -5 DEG C-15 DEG C, dripping 10-12% of sodium carbonate solution, and adjusting the pH value of diazotization reaction solution to 5-7; further carrying out reduction reaction: adding sodium sulfite solution into the four-neck flask, reducing the temperature to 0-20 DEG C and starting stirring; dripping the diazotization reaction solution into the sodium sulfite solution in batches, keeping the temperature at 0-25 DEG C, and stirring at the room temperature for 1-3h; adding the concentrated hydrochloric acid, and carrying out heating reflux for 1-4h; and reducing the temperature to 0 DEG C-20 DEG C, filtering, drying, and obtaining the para-trifluoromethyl phenyl hydrazine hydrochloride. The yield is greater than 75% and the purity is 97%-99%.

Description

technical field [0001] The invention belongs to the technical field of compounds with a fluorocarbon alkyl group and an amino group on a six-carbon aromatic ring, and relates to the chemical reaction technology of diazotization and reduction of amines. Background technique [0002] The method for preparing p-trifluoromethylphenylhydrazine hydrochloride from p-trifluoromethylaniline is the preparation process of trifluoromethylphenylhydrazine hydrochloride by using the reduction of diazonium salt. The restoration methods currently used mainly include: [0003] 1) SO 2 Reduction with ammonia water (Tetrahedron, 1960, Vol.8, pp.67 to 72.), its disadvantage is that it is troublesome to feed sulfur dioxide gas, and the amount of feeding is not easy to control. [0004] 2) Reduction of stannous chloride and concentrated hydrochloric acid (J.Org.Chem.1995, 60, 2411-2422), its disadvantage is that stannous chloride is relatively toxic, and it is inconvenient and troublesome to ope...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C243/22C07C241/02
Inventor 李艳王永灿
Owner 大连凯飞精细化工有限公司
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