In order to reduce the waste water and increase the conversion rate of products, domestic scientific research institutions and production enterprises used domestic technology for reference, improved the existing rubber accelerator M process, and achieved results. Domestic researchers have developed a similar solvent extraction process with foreign countries, but there are also problems. Environmental protection, safety and high efficiency selection of new organic solvents is the key to the purification of M by solvent method. The existing solvent extraction methods include solvent crystallization method, distillation-extraction method, solid-liquid extraction method, liquid-liquid extraction method and so on. However, the technology is not perfect enough.
At present, organic solvents can choose toluene, carbon disulfide, aniline, benzene and so on.
Using carbon disulfide as solvent, cost control and safety control are prominent problems. Although the quality is stable and the products can meet the international requirements, the safety needs to be improved due to the flammability and explosion of carbon disulfide.
When aniline is used as solvent, aniline is slightly soluble in water, resulting in an increase in the amount of aniline in the solution, which is not conducive to production.
Benzene and toluene are used as solvents, the solubility of the resin is small, the purity of product M is affected, and the recovery of solvent is also considered. Moreover, benzene and toluene are flammable and explosive, the safety factor is low, and volatilization causes solvent loss in the air. Lead to the increase of production costs, but also cause harm to the atmospheric environment.