A new process for purifying rubber accelerator mbt

Abstract

The invention discloses a new process for purifying rubber accelerator MBT, which belongs to the field of fine chemical industry. In the present invention, the crude rubber accelerator MBT is dissolved in an organic naphthalene solvent at 170-200°C, stirred for 1-3 hours, and filtered hot, and the filtrate is slowly cooled to 20-60°C, filtered, and dried to obtain light yellow MBT crystals. The present invention uses the organic naphthalene solvent liquid-liquid extraction of crude MBT to realize the refining of the rubber accelerator MBT, which can effectively avoid the shortcomings of the current industrially used organic solvents such as toluene, carbon disulfide, aniline, etc., which cannot really realize liquid-liquid extraction and poor product quality. The whole extraction is carried out at 170~200°C (170°C higher than the melting point of MBT), and the liquid-liquid contact extraction is truly realized, and can be crystallized after cooling, filtered and dried to obtain high-purity light yellow MBT, with a melting point of more than 172°C and a purity of more than 98%. The whole process produces no waste water, which is very suitable for industrial production.

Description

technical field [0001] The invention relates to the field of fine chemicals, in particular to a new process for purifying rubber accelerator MBT. Background technique [0002] Rubber accelerator MBT is a general-purpose accelerator, widely used in various rubbers, and has rapid vulcanization acceleration in natural rubber and general synthetic rubber. In addition, it also has certain plasticizing and anti-aging properties, and can be used as a retarder in chloroprene rubber. At the same time, its derivatives such as: CZ, NS, DZ, NOBS, etc. have better rubber vulcanization acceleration performance. Rubber accelerator MBT is easy to disperse in rubber and does not pollute. It is mainly used in the manufacture of tires, inner tubes, tapes, rubber shoes and industrial products. [0003] At present, the rubber accelerator MBT is generally produced by the high-pressure method in industry, that is, aniline, sulfur, and carbon disulfide are reacted at high temperature (250-300°C)...

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Problems solved by technology

[0005] In the traditional acid-base method, air, oxygen or hydrogen peroxide are used as oxidants. Although higher-quality MBT products can be obtained, a large amount of high-salt, high-pollution wastewater and odorous gases will be generated during production, which will pollute the environment and is not conducive to the occupational health of workers. ; And prone to peroxidation to oxidize MBT salt to DM, and the end point is not easy to judge

[0006] The solvent method uses organic solvents (such as toluene, carbon disulfide, aniline, chlorobenzene, methanol, etc., one or more compound) to liquid-liquid extraction or solid-liquid extraction of crude MBT, such as patents CN102718728A, CN104031003 A, CN105061357 A, CN1687040A, CN101693701A, etc. Patent, although it can realize the refining of crude MBT, but because the liquid-liquid extraction cannot be realized, the obtained MBT product has low purity and cannot be directly used as commercial grade MBT for rubber vulcanization; at the same time, the obtained MBT product is used for sulfenamide raw materials , it will affect the product index of downstream sulfenamide accelerators

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