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Novel synthesis process of P-chlorophenylhydrazine hydrochloride

A technology for the synthesis of chlorophenylhydrazine hydrochloride, applied in hydrazine preparation, organic chemistry, etc., can solve the problems of asphalt-like by-products, low temperature for reaction, cumbersome operation, etc., achieve low operating cost, convenient temperature control, Effects with simple processing steps

Inactive Publication Date: 2014-06-11
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The problem with the first method is that the yield is relatively low, but the reaction requires low temperature, the reagents are expensive, and the pollution is serious
The problem with the second method is that the yield can reach 86.5%, but it needs to be adjusted to pH = 6~7 with NaOH. If the control is not good, there will be asphalt-like by-products, and the preparation process needs to be heated and controlled several times. Response, cumbersome to operate

Method used

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  • Novel synthesis process of P-chlorophenylhydrazine hydrochloride
  • Novel synthesis process of P-chlorophenylhydrazine hydrochloride

Examples

Experimental program
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Effect test

Embodiment 1

[0027] Step 1: Add 0.555 mol of hydrochloric acid, 60 mL of water, and 0.225 mol of p-chloroaniline to the reaction flask, heat up to 60-70°C, and cool down slowly to 0-5°C after all p-chloroaniline hydrochloride is dissolved. ℃, slowly drop in a solution made of 0.231mol sodium nitrite and 40mL water, finish adding dropwise for 20 minutes, stir for 30 minutes, check the reaction end point with starch potassium iodide test paper, add 0.021mol urea, stir for 10 minutes, filter and refrigerate.

[0028] The second step: in the reaction bottle, under strong stirring, dissolve 0.45mol anhydrous sodium sulfite in 120ml water, and dissolve 0.225mol sodium bisulfite in 50ml water at the same time. After the anhydrous sodium sulfite is completely dissolved, mix the two solutions to make Its pH is maintained at 6.5, and the above-mentioned diazonium salt is slowly added below the liquid level at room temperature, reacted at 80°C for 2 hours, p-chloroaniline and sodium bisulfite are 1:1,...

Embodiment 2

[0031] The reaction steps are exactly the same as in Example 1, except that for the second step, the dropping temperature is 40°C, and p-chloroaniline diazonium salt is slowly added below the liquid level for reaction, wherein the reduction temperature becomes 60°C, and the reducing agent is anhydrous The molar ratio of sodium sulfite to sodium bisulfite was 1.8:1 and the pH was maintained at 7. In the third step, the molar ratio of hydrochloric acid to p-chloroaniline is changed to 1:2.3 to keep the pH at 3. The solid yield of reddish p-chlorophenylhydrazine hydrochloride is 89.77%. The confirmation method of the compound of this article embodiment is the same as that of Example 1.

Embodiment 3

[0033] The reaction steps are exactly the same as in Example 1, except that the reduction temperature in the second step is changed to 70°C, the molar ratio of reducing agent anhydrous sodium sulfite to sodium bisulfite is 1.5:1, and the pH is maintained at 6. In the third step, the molar ratio of hydrochloric acid to p-chloroaniline is changed to 1:2.3 to keep the pH at 3. The solid yield of reddish p-chlorophenylhydrazine hydrochloride is 92.79%. The confirmation method of the compound of this article embodiment is the same as that of Example 1.

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Abstract

The invention discloses a preparation method of P-chlorophenylhydrazine hydrochloride. The method comprises the following steps: diazotizing chloroaniline taken as a raw material so as to prepare a corresponding diazonium salt; mixing anhydrous sodium sulfite with sodium hydrogen sulfite in a stirring manner, maintaining a pH (Power Of Hydrogen) value within 6 to 7, controlling a temperature below 40 DEG C, slowly adding the diazonium salt below a liquid surface and reacting at the temperature of 60 DEG C to 90 DEG C according to the molar ratio of the p-chloroaniline to the sodium hydrogen sulfite being 1:(1-1):3; maintaining the unchanged pH value in the step 2, slowly adding hydrochloric acid so as to maintain the pH value within 1 to 3, reacting for 1 to 3 hours at the reaction temperature of 40 DEG C to 90 DEG C, cooling to a room temperature, filtering and drying so as to obtain a reddish P-chlorophenylhydrazine hydrochloride solid. The pH value of the reaction system is maintained within 6 to 7 by taking a mixture of the sodium sulfite and the sodium hydrogen sulfite as a reducing agent, so that the phenomenon that the pH value is always regulated by NAOH (sodium hydroxide) or HCL (hydrogen chloride) in a reaction process is avoided; and the repeated heating during the reaction process is not required, so that the temperature is convenient to control; and the adding amount of water is reduced, so that the discharge of wastewater is greatly reduced, namely, the wastewater treatment at a later period is avoided. As a result, the cost is lowered.

Description

technical field [0001] The invention relates to the fields of organic synthesis and pesticide synthesis, in particular to a novel synthesis process of p-chlorophenylhydrazine hydrochloride. Background technique [0002] p-Chlorophenylhydrazine hydrochloride is an important chemical production raw material and intermediate in my country, and is often used in the manufacture of medicines, pesticides and other fine chemical qualities. There are usually two types of p-chlorophenylhydrazine hydrochloride: (1) p-chloroaniline is used as raw material, diazotized by hydrochloric acid and sodium nitrite, and the reduction of stannous chloride is continued at about -10°C, for example, the total collection of p-chloroaniline The rate reached about 64%. (2) p-Chloroaniline is used as a raw material, diazotized by hydrochloric acid and sodium nitrite, reduced by sodium bisulfite, and then hydrochloric acid is acidified to form a salt. Among the reducing agents are anhydrous sodium sulf...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C243/22C07C241/02
Inventor 易文斌黄敏蔡春
Owner NANJING UNIV OF SCI & TECH
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