Fine purification method for rubber vulcanization accelerant 2-mercaptobenzothiazole (M)

Abstract

The invention relates to a method for refining a thiofide 2-mercaptobenzothiazole (M). The method is characterized in that an extraction method and an alkali dissolving and acid isolation method are creatively combined. The method comprises the following steps: crude thiofide M is extracted by using toluene for three times to remove resin impurities so as to obtain high-purity thiofide M; the thiofide M in the resin is purified by the alkali dissolving and acid isolation method; and the thiofideoluene is reclaimed by a distillation method. By adopting the processing, the thiofide M with high purity, high melting point and short melting period can be obtained.

Description

technical field [0001] The invention relates to a method for refining a rubber vulcanization accelerator 2-mercaptobenzothiazole (M), which belongs to the field of fine chemicals. Background technique [0002] With the development of the rubber industry, people pay more and more attention to the research and production of vulcanization accelerators. Vulcanization accelerator plays a very important role in the rubber vulcanization process. It can greatly speed up the reaction between rubber and vulcanizing agent, improve productivity, and at the same time improve the physical and mechanical properties of vulcanized rubber. Rubber vulcanization accelerator M is a kind of Usually, the impurity in this accelerator is mainly resin and intermediate product (such as benzothiazole), and the existence of impurity makes the quality of the product not high. [0003] At present, most of the refining of rubber vulcanization accelerator M in my country adopts the traditional alkali-disso...

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Problems solved by technology

Vulcanization accelerator plays a very important role in the rubber vulcanization process. It can greatly speed up the reaction between rubber and vulcanizing agent, improve productivity, and at the same time improve the physical and mechanical properties of vulcanized rubber. Rubber vulcanization accelerator M is a kind of An important accelerator, usually, the impurity in this accelerator is mainly resin and intermediate product (such as benzothiazole), the existence of impurity makes the quality of the product not high

[0003] At present, most of the refining of rubber vulcanization accelerator M in my country adopts the traditional alkali-dissolving acid analysis method. This process consumes a large amount of alkali and is costly. In addition, it has obvious defects in environmental protection. It not only produces a lot of black tar-like substances that are difficult to handle , and produce a large amount of waste water

[0004] There is also an aniline extraction and crystallization method in the literature to refine the rubber vulcanization accelerator M, which uses the rubber vulcanization accelerator M to be insoluble in aniline to remove the aniline-soluble resin, but this method has a long process and complicated operation

[0005] Another toluene alkali-soluble extraction method is to add the crude product rubber vulcanization accelerator M to an excessive amount of alkali solution, extract the filtrate with toluene several times to remove soluble impurities and part of insoluble impurities, and then add acid to precipitate the rubber vulcanization accelerator M, Although this method combines the advantages of the high purity of the solvent extraction method and the high yield of the alkali dissolution method, it still produces a large amount of waste water.

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