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Crystallization purification method of thiourea

A purification method and thiourea technology are applied in the field of crystallization and purification of high-quality thiourea, which can solve problems such as purification of rare thiourea products, and achieve the effects of improving purity, uniform crystallization, and preventing the color of feed liquid from becoming darker.

Active Publication Date: 2013-03-20
SHANDONG EFIRM BIOCHEMISTRY & ENVIRONMENTAL PROTECTION CO LTD
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  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

[0004] The synthesis of thiourea by calcium cyanamide method is a mature technology widely used. Calcium cyanamide and hydrogen sulfide are used as raw materials to synthesize thiourea in an alkaline environment, and the product is purified by crystallization. There are a large number of literature reports on the improvement of thiourea production process, but there are few reports on the purification of thiourea products

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Add 0.32 kg of AEO-7 fatty alcohol polyoxyethylene ether to 632.87 kg of thiourea-containing feed solution (expected thiourea yield of 70.38 kg), stir and react at 30°C for 2 hours, cool down to 8°C at a rate of 2°C / h to crystallize, and filter , the crystalline solid was dried at 80°C to obtain 69.54 kg of thiourea, with a content of 99.5%, as white crystals.

Embodiment 2

[0018] Add 0.62 kg of JFC-2 fatty alcohol polyoxyethylene ether to 619.27 kg of feed liquid containing thiourea (the expected thiourea yield is 72.86 kg), stir and react at 50°C for 3 hours, cool down to 20°C at a rate of 2°C / h to crystallize, filter , the crystalline solid was dried at 75°C to obtain 69.54 kg of thiourea, with a content of 99.3%, as white crystals.

Embodiment 3

[0020] Add 0.26 kg of AEO-15 fatty alcohol polyoxyethylene ether to 651.28 kg of thiourea-containing feed solution (the expected thiourea output is 77.84 kg), stir and react at 40°C for 2.5h, cool down to 14°C at a rate of 1.5°C / h for crystallization, After filtering, the crystalline solid was dried at 80°C to obtain 75.4 kg of thiourea, with a content of 99.6%, as white crystals.

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Abstract

The invention belongs to the technical field of fine chemical industry and relates to crystallization purification technology of chemicals, in particular to the crystallization purification technology for of thiourea. According to the crystallization purification method of the thiourea, surfactant is mainly adopted to solubilize impurity of the thiourea solvent system in a selected mode, the crystallization ability of the impurity is reduced, the impurity is left in fluid phase, and the purity degree of the thiourea is increased. The crystallization purification method of the thiourea is simple in operation, easy to control, low in energy consumption and free of special equipment input, obtained products are even in crystallization and good in whiteness, content of crystallization is higher than 99%, and the crystallization purification method of the thiourea suitable for crystallizing the thiourea product in industrial production, satisfying demands of medicine, fine chemical and other industries, and improving purity degree of down-stream products.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, and relates to the crystallization and purification technology of chemicals, in particular to the crystallization and purification technology of high-quality thiourea. Background technique [0002] Thiourea is a fine chemical product that is currently in short supply in the domestic and foreign markets. It is a white shiny diamond-shaped hexahedral crystal, bitter in taste, slightly toxic, and has a density of 1.406 g / cm 3 , melting point is 180-182 ℃, decomposes at higher temperature, easily soluble in water, soluble in ethanol when heated, very slightly soluble in ether, easy to deliquescence in air. [0003] Thiourea can be used in the manufacture of drugs (sulfathiazole, methionine), epoxy resins, dyes, rubber vulcanization accelerators, metal mineral flotation agents, diazo sensitizers, thiourea peroxide and cold perm agents, etc.; it can also be used in resin compression molding Pow...

Claims

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Application Information

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IPC IPC(8): C07C335/02
Inventor 许倩倩吴文雷吴志红张建林常忠臣马韵升史庆苓
Owner SHANDONG EFIRM BIOCHEMISTRY & ENVIRONMENTAL PROTECTION CO LTD
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