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Synthesis method for aromatic hydrazine sulfate

A synthetic method and sulfate technology, applied in the preparation of hydrazine, organic chemistry, etc., can solve the problems of high infrastructure cost and operating cost, high acidity, complicated operation, etc., and achieve high recycling value, high yield and purity, and application good effect

Active Publication Date: 2017-04-19
ZHEJIANG QICAI ECO TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are the following problems: (1) using sulfuric acid as an acidifying agent, the acidity of the required sulfuric acid is relatively high, and the cost is relatively high (2) the temperature of the diazo process is -5~-15°C, which is relatively low and difficult to control , high cost; (3) obtain phenylhydrazine by extraction and separation, complicated operation, high capital construction cost and operating cost; (4) use ammonia gas to adjust pH in the extraction process, ammonia gas is volatile and easy to generate air pollution; (5) Adopt ammonium nitrite to make diazonium reagent, ammonium nitrite is easy to decompose, easy to explode, and the risk is higher; (6) adopt solid reducing agent, easily cause local reaction violently, the problem of reaction efficiency reduction; (7) phenylhydrazine yield Low, about 80% or so

Method used

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  • Synthesis method for aromatic hydrazine sulfate
  • Synthesis method for aromatic hydrazine sulfate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Weighing p-chloroaniline 12.7g joins 60g mass fraction and is in the sulfuric acid of 11%, ice bath cools down to 5 ℃, keeps this temperature and slowly adds 47g of nitrosylsulfuric acid (hereinafter referred to as liquid sub) with a content of 28%, After reacting for 2 hours, use starch potassium iodide test paper to measure the completion of the reaction of p-chloroaniline to obtain the diazonium salt.

[0025] Weigh 30g of sodium sulfite, add water to form a 20% sodium sulfite solution, and simultaneously add dropwise the diazonium salt generated in the above steps and 30% liquid caustic soda in the solution, and keep the pH at 6-7 during the dropping process. After the salt was added dropwise, the temperature was raised to 70° C. and kept for 13 hours. After the reduction reaction was completed, it was filtered to obtain the filtrate as the reduction product.

[0026] The obtained reduced product was heated to 80°C, slowly added dropwise with 20% sulfuric acid to ke...

Embodiment 2

[0030] Weigh 12.7g of p-chloroaniline and add it to 60g of sulfuric acid with a mass fraction of 11%, cool it in an ice bath to 5°C, keep the temperature and slowly add 30g of 40% liquid solution dropwise, react for 2h, and measure it with starch potassium iodide test paper After the reaction of p-chloroaniline is completed, the diazonium salt is obtained.

[0031] Weigh 28g sodium bisulfite, add water to make 20% sodium bisulfite solution, neutralize to pH 6-7 with 30% liquid caustic soda, add dropwise the weight generated by the above steps in the solution simultaneously Nitrogen salt and liquid caustic soda with a mass fraction of 30%, keep the pH at 6-7 during the dropwise addition, raise the temperature to 70°C after the diazonium salt is added dropwise, keep it warm for 3 hours, after the reduction reaction is completed, filter to obtain the filtrate as the reduction product.

[0032] The obtained reduced product was heated to 80°C, slowly added dropwise with 20% sulfuri...

Embodiment 3

[0035] Weigh 12.7g of p-chloroaniline and add it to 60g of sulfuric acid with a mass fraction of 50%, cool it down to 5°C in an ice bath, and slowly add sodium nitrite solution with a content of 28% dropwise at this temperature, react for 2 hours, and use starch potassium iodide test paper It is determined that the reaction of p-chloroaniline is completed and the diazonium salt is obtained.

[0036] Weigh 30g of sodium sulfite, add water to form a 20% sodium sulfite solution, and simultaneously add dropwise the diazonium salt generated in the above steps and 30% liquid caustic soda in the solution, and keep the pH at 6-7 during the dropping process. After the salt was added dropwise, the temperature was raised to 70° C. and kept for 3 hours. After the reduction reaction was completed, it was filtered to obtain the filtrate as the reduction product.

[0037] The obtained reduced product was heated to 80°C, slowly added dropwise with 20% sulfuric acid to keep the pH at 2, and re...

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Abstract

The invention discloses a synthesis method for aromatic hydrazine sulfate. The synthesis method includes the steps that firstly, aromatic amine is added in sulfuric acid with the mass fraction ranging from 15% to 65%, the temperature is lowered to -5-15 DEG C, a diazotization reagent is dropwise added in the reaction liquid, and diazonium salt is obtained after reaction; secondly, a reducing agent is prepared into a solution, a reducing solution is obtained, the diazonium salt obtained in the first step is dropwise added in the reducing solution, heating reduction is conducted after drop-by-drop addition is completed, and reducing material liquid is obtained through filtration; and thirdly, the reducing material liquid obtained in the second step is heated, dilute sulphuric acid is dropwise added in the reducing material liquid to conduct the acidolysis reaction, the temperature is lowered after the reaction is finished, the aromatic hydrazine sulfate is separated out, a filter cake and filtrate are obtained through filtration, the filter cake is washed with dilute sulphuric acid, and an aromatic hydrazine sulfate product is obtained, and sodium sulfate salt is recycled after the filtrate is preprocessed. Compared with a traditional process, the obtained aromatic hydrazine sulfate is high in yield and purity, the purity reaches 97% or above, the yield is higher than 91%, salt in the wastewater obtained through the reaction is the simplex sodium sulfate salt, and the recycling value is high.

Description

technical field [0001] The invention relates to the field of organic compound synthesis, in particular to a method for synthesizing aromatic hydrazine sulfate, a commonly used pharmaceutical intermediate. Background technique [0002] As an important chemical raw material and intermediate, aromatic hydrazine plays a very important role in the fields of organic synthesis and fine chemicals such as medicine, pesticides and dyes, especially in recent years with the in-depth research and continuous expansion of heterocyclic compounds , the role of aromatic hydrazines in the fields of fine chemicals and organic synthesis is becoming more and more obvious. [0003] At present, the synthesis method of aromatic hydrazine is mainly to carry out diazotization reaction under hydrochloric acid condition with aromatic amine as raw material, the obtained diazonium salt is reduced with sodium sulfite or sodium bisulfite, after the reduction solution is acidolysis with dilute hydrochloric a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C243/22C07C241/02
CPCC07C241/02C07C245/20C07C243/22
Inventor 郭晓峰梁伟张清义沈一鸣傅智杰赵骏吴勇前
Owner ZHEJIANG QICAI ECO TECH CO LTD
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