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A kind of preparation method of p-substituted phenylhydrazine hydrochloride

A technology of phenylhydrazine hydrochloride and hydrochloric acid is applied in the field of preparation of para-substituted phenylhydrazine hydrochloride, which can solve the problems of low purity, low yield and high cost, and achieve the effect of high purity and high yield

Active Publication Date: 2022-02-22
HEBEI NORMAL UNIV FOR NATTIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But this method is still exactly the same as the sodium bisulfite method, has high cost, low yield, defects such as low purity

Method used

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  • A kind of preparation method of p-substituted phenylhydrazine hydrochloride

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preparation example Construction

[0021] The invention provides a kind of preparation method of p-substituted phenylhydrazine hydrochloride, comprising the following steps:

[0022] (1) Mixing para-substituted aniline, hydrochloric acid, water and a phase transfer agent, and heating the resulting mixed system to obtain a dissolved para-substituted aniline hydrochloride system;

[0023] (2) Mixing the dissolved p-substituted aniline hydrochloride system and sodium nitrite solution at a temperature of -10 to 10°C, and then performing a diazonium reaction to obtain a diazonium salt;

[0024] (3) At a temperature of 65-75°C, mix the obtained diazonium salt and sodium sulfite solution and perform a reduction reaction to obtain a para-substituted phenylhydrazine system;

[0025] (4) Mixing the p-substituted phenylhydrazine system and hydrochloric acid and then carrying out acid precipitation reaction to obtain p-substituted phenylhydrazine hydrochloride.

[0026] The invention mixes para-substituted aniline, hydroc...

Embodiment 1

[0045] Preparation of p-methylphenylhydrazine hydrochloride:

[0046] Add 21.4 g of p-toluidine (0.2 mol), 50 ml of 37% (0.6 mol) hydrochloric acid, 40 mL of water and 1.0 g of Triton X-100 into the beaker, raise the temperature to 85°C (dissolution temperature), and wait until all After dissolving the methylaniline hydrochloride, cool it to 5°C with an ice-salt bath, slowly drop in a solution made of 14.5g (0.21mol) sodium nitrite and 45ml water, stir for 15 minutes, and filter out the formed diazo Salt.

[0047] Put 200mL of the prepared 2.5 mol / L sodium sulfite solution into a beaker and heat it to 70°C, slowly add the above-mentioned filtered diazonium salt, and then keep it at 70°C for 2h. After the heat preservation, add 1.2g of zinc powder and 2.0g of activated carbon, continue heat preservation for 1 hour, add 70 mL of 37% concentrated hydrochloric acid, continue heat preservation for 1 hour, filter while hot, transfer to a beaker and cool to room temperature naturall...

Embodiment 2~5

[0050] The preparation of each product was carried out in the manner described in Example 1, wherein the distinguishing technical features are shown in Table 1.

[0051] Example 2 Example 3 Example 4 Example 5 raw material p-Fluoroaniline p-Chloroaniline p-Bromoaniline p-Hydroxyaniline end product p-Fluorophenylhydrazine hydrochloride p-Chlorophenylhydrazine hydrochloride p-bromophenylhydrazine hydrochloride p-Hydroxyphenylhydrazine hydrochloride Aniline hydrochloride dissolution temperature 40℃ 70℃ 75℃ room temperature Diazo reaction temperature 0℃ 10℃ 5℃ 5℃ reducing agent Sulfite Sulfite Sulfite Sulfite reduction reaction temperature 70℃ 70℃ 75℃ 70℃ reduction reaction time 2h 3h 3h 3h Whether to add carbon powder, zinc powder no yes yes no acid precipitation reaction temperature 80℃ 80℃ 80℃ 80℃ Acid analysis reaction time 1h 1h 1h 1h average total yi...

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Abstract

The invention belongs to the technical field of organic synthesis, and provides a preparation method of p-substituted phenylhydrazine hydrochloride: mixing p-substituted aniline, hydrochloric acid, water and a phase transfer agent, and heating the obtained mixed system to obtain dissolved Para-substituted aniline hydrochloride system; at a temperature of -10~10°C, mix the dissolved para-substituted aniline hydrochloride system with sodium nitrite solution and then perform diazonium reaction to obtain diazonium salt; at 65 At a temperature of ~75°C, the obtained diazonium salt and sodium sulfite solution are mixed for reduction reaction to obtain a para-substituted phenylhydrazine system; the para-substituted phenylhydrazine system is mixed with hydrochloric acid for acid precipitation reaction to obtain a para-substituted Phenylhydrazine hydrochloride. The method of the invention has the advantages of high yield, high purity, time-saving and labor-saving, and low cost. According to the experimental results of the examples, it can be seen that the yield of the method of the present invention can reach 92.6%, and the purity can reach a purity level of more than 99%.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a preparation method of p-substituted phenylhydrazine hydrochloride. Background technique [0002] At present, p-substituted phenylhydrazine hydrochloride is generally prepared by reducing diazonium salt with excess stannous chloride and concentrated hydrochloric acid saturated solution at about 0°C to 10°C. However, this method has a low yield and requires a long time of water bath heating, which is time-consuming, laborious and consumes more energy. [0003] It is also reported in the prior art that after the diazonium salt is dropped into the saturated sodium bisulfite solution, the temperature of the reaction solution is raised to the reflux temperature, and then kept for a period of time to directly obtain phenylhydrazine hydrochloride. However, although this method saves the acid analysis and is easy to operate, it has high cost, low yield and low purity, and nee...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C241/02C07C243/22
CPCC07C241/02C07C209/00C07C213/08C07C245/20
Inventor 吴琼张恒强金铜音马闯陈鸿利
Owner HEBEI NORMAL UNIV FOR NATTIES
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