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Method for producing salicylic acid by refining salicylic acid solution

A technology of sodium salicylate and refining treatment, applied in the preparation of carboxylate, chemical instruments and methods, preparation of organic compounds, etc., can solve the problems of poor production environment, low production efficiency, high energy consumption, and achieve less consumption of raw materials , The effect of large production capacity and low energy consumption

Inactive Publication Date: 2008-03-19
SHANDONG XINHUA LONGXIN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This process has low production efficiency, high energy consumption, and poor production environment. Therefore, it is necessary to study the production process of salicylic acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] 100kg of sodium salicylate solution with a mass concentration of 20% is heated to 50-75°C, and the pH value is adjusted to 4 with a mass concentration of 30% sulfuric acid. Add 0.8 kg of activated carbon (which can be adjusted into a paste with water) and stir and keep warm for 2 hours at a temperature of 50-75°C. Repeatedly filter (filter with diatomaceous earth) under heat preservation conditions until the filtrate is clear, add 0.06 kg of sodium hydrosulfite, stir well, filter, and put the filtrate in a beaker. Adjust the pH value to 1 with a mass concentration of 20% sulfuric acid to separate out 16.5 kg of salicylic acid, and obtain 99.3% pure salicylic acid after cooling, conventional filtration, pure water washing and drying.

Embodiment 2

[0016] 100kg of sodium salicylate solution with a mass concentration of 40% is heated to 50-75°C, and the pH value is adjusted to 6 with a mass concentration of 40% sulfuric acid. Add 0.4 kg of activated carbon (which can be adjusted into a paste with water) and stir and keep warm for 4 hours at a temperature of 50-75°C. Repeated filtration (diatomaceous earth filtration) under heat preservation conditions until the filtrate is clarified, add 0.08 kg of sodium hydrosulfite, stir well, then filter, and put the filtrate in a beaker. Adjust the pH value to 2.5 with a mass concentration of 30% sulfuric acid to separate out 33.0 kg of salicylic acid. After cooling, conventional filtration, pure water washing and drying, pure salicylic acid with a content of 99.4% was obtained.

Embodiment 3

[0018] 100 kg of sodium salicylate solution with a mass concentration of 20% is heated to 50-75° C., and the pH value is adjusted to 3 with a mass concentration of 20% sulfuric acid. Add 1 kg of activated carbon (which can be made into a paste with water) and stir and keep warm for 3 hours at a temperature of 50-75°C. Repeatedly filter (filter with diatomaceous earth) under heat preservation conditions until the filtrate is clear, add 0.04kg of sodium hydrosulfite, stir evenly, filter, and put the filtrate in a beaker. Adjust the pH value to 1.5 with a mass concentration of 40% sulfuric acid to separate out 16 kg of salicylic acid, and obtain 99.5% pure salicylic acid after cooling, conventional filtration, pure water washing and drying.

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Abstract

The invention relates to a method which utilizes sodium salicylate solution to refine, process and produce salicylic acid. Phenol reacts with liquid alkali, so that sodium phenolate is generated, the dried sodium phenolate reacts with carbon dioxide to generate sodium salicylate, which is then resolved in water, and therefore the sodium salicylate solution is produced. The first step is to regulate the pH value, that is, the sodium salicylate solution with twenty to forty percent of mass concentration is heated until 50 DEG C to 75 DEG C, and the pH value is regulated to four to six; the second step is to preserve heat, that is, the sodium salicylate solution is added with activated carbon and thermally insulated for two to four hours under the condition of temperature between 50 DEG C and 75 DEG C; the third step is filtration, the sodium salicylate solution is filtered, the filtrate is added with rongalite when filtrate is clean, and after five to twenty minutes, the filtrate is filtered into an acid eduction pot; in the fourth step, the salicylic acid is separated out from the acid eduction pot by utilizing vitriol to regulate the pH valve to one to two point five, and a pure product with more than ninety nine point three percent of content is produced after temperature reduction, filtration, washing and drying of the salicylic acid. The production technique of the invention has the advantages of simple process, convenient operation, little pollution, low material consumption and high purity of products, and meanwhile, the invention is convenient for industrialized production.

Description

technical field [0001] The invention belongs to the production process of salicylic acid, in particular to a method for producing salicylic acid by refining sodium salicylate solution. Background technique [0002] Salicylic acid is a raw material widely used in medicine, chemical industry and other industries. At present, the sublimation process is generally used in China to produce salicylic acid. The process uses phenol and liquid caustic soda as raw materials to react to produce sodium phenoxide, and after drying, reacts with carbon dioxide to produce sodium salicylate, which is dissolved in water to obtain sodium salicylate solution, and then undergoes steps such as acid precipitation, centrifugation, drying, and sublimation to obtain salicylate Sour finished product. The production efficiency of this process is low, the energy consumption is high, and the production environment is poor. Therefore, the research on the production process of salicylic acid is very neces...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C65/10C07C51/15
Inventor 韩志刚
Owner SHANDONG XINHUA LONGXIN CHEM
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