Rubber accelerator MBT is a general-purpose accelerator, which is widely used in various rubbers and has fast vulcanization promotion effect in natural rubber and general synthetic rubber. Besides, it also has certain plasticity and anti-aging property, and can be used as retardant in neoprene. Meanwhile, its derivatives such as CZ, NS, DZ, NOBS, etc. have more excellent rubber vulcanization promotion performance.

At present, there are two main methods of refining MBT: acid-base method and solvent method. The traditional acid-base method uses air, oxygen or hydrogen peroxide as oxidant, although it can get higher quality MBT products, but in the production of a large amount of high salt and high pollution wastewater and odor gas, polluting the environment, which is not conducive to the occupational health of workers; the solvent method uses organic solvents (such as toluene, carbon disulfide, aniline, chlorobenzene, methanol and other one or several compounds) to liquid-liquid extraction or solid-liquid extraction of crude MBT, although it can achieve the refining of crude MBT, but because it can not really achieve liquid-liquid extraction, the obtained MBT products have low purity and can not be used directly as commercial grade MBT for rubber vulcanization; at the same time, when the obtained MBT products are used for hyposulfamide raw materials, it will affect the product index of downstream hyposulfamide accelerators. There is an urgent need to find a crystalline solvent with high yield, high purity, good safety and environmental friendly.

Through computer-aided molecular design, an organonaphthalene solvent was finally preferably selected, which can be used as an efficient extraction reagent for MBT crude products. The liquid-liquid extraction of MBT crude with organic naphthalene solvent can effectively avoid the shortcomings of the current industrial use of toluene, carbon disulfide, aniline and other organic solvents can not really achieve liquid-liquid extraction and poor product quality, the boiling point of tetrahydronaphthalene is greater than 200 ℃, the whole extraction 170-200 ℃ (greater than the melting point of MBT 170 ℃), the real liquid-liquid contact extraction, filtration and drying to obtain high purity of light yellow MBT, melting point greater than 172 ℃, purity greater than 98%.