Process transformation of accelerator M from acid-base method to solvent method

Rubber accelerator M (chemical name 2-sulfonylbenzothiazole) is not only an important rubber accelerator, but also an important intermediate for the synthesis of other accelerators. It has excellent vulcanization accelerator performance, wide use and large consumption. It is the parent for the synthesis of other after-effect accelerators (such as thiazole accelerator, secondary sulfonamide accelerator). For example, rubber accelerator DM, CZ, NS, MZ, etc. are all from the parent M.

Characteristics of acid-base method M

Accelerator MBT (M) is a relatively large type of rubber vulcanization accelerator products. The advantages of acid-base method M are good quality, high purity and good application effect of rubber products. However, in the production process of acid-base method M, which is widely used in China, there are problems such as high consumption of raw materials and serious environmental pollution. The wastewater produced has the characteristics of high salinity, high pollutant concentration and difficult degradation, which makes the wastewater treatment difficult. Using this method to produce 1 ton of M, more than 20 tons of wastewater will be produced, including about 0.6 tons of sodium sulfate and more than 4000mg/L of COD; At the same time, the production process of acid-base method M also has waste gas and slag emissions. The waste gas is mainly H2S, and the waste residue is mainly the by-product of the synthesis process, which accounts for about 15% of the total synthesis.

M Clean production solvent method

In recent years, the clean production of M has also become a hot and difficult point in the development of rubber additives. M The cleaning process adopts solvent method, using organic solvent to replace the original alkali dissolution, acid precipitation and other processes. More than 20 tons of diluted caustic soda, diluted sulfuric acid and process water were originally produced for 1 ton of M, but now no water solvent is used. Without water, there is no waste water, and the goal of source control has been truly achieved. Based on the domestic annual output of 200000 tons M, if promoted in the whole industry, the annual output of wastewater can be reduced by 4 million tons, and the discharge of COD, BOD, ammonia nitrogen and other pollutants can be greatly reduced, reducing environmental pollution, protecting the human social environment, and promoting the sustainable development of enterprises!

Different process routes of solvent method M

In order to reduce waste water and improve product conversion rate, domestic scientific research institutions and production enterprises have improved the existing rubber accelerator M process with reference to domestic technology, and achieved results. Domestic researchers have developed similar solvent extraction refining processes, but there are also problems. The selection of environmentally friendly, safe and efficient new organic solvents is the key to the purification of M solvent. The existing solvent extraction methods mainly include solvent crystallization, distillation extraction, solid-liquid extraction, liquid-liquid extraction, etc., but the technology is not perfect. At present, the organic solvent can be toluene, carbon disulfide, aniline, benzene, etc.