Preparation method of rubber accelerator dibenzothiazyl disulfide

Abstract

The invention relates to a preparation method of rubber accelerator dibenzothiazyl disulfide. The preparation method comprises the following steps of: measuring 500 ml of M-Na salt solution; dropwise adding mixed oxidant into a container with the M-Na salt solution according to a proportion of 58-80 ml of mixed oxidant per every liter of M-Na salt solution under a stirring condition at 70-80 DEG C; controlling the pH (Potential of Hydrogen) to be stable in a range of 6.5 to 7.5; adding 0.1-0.2 g of 30 percent sodium hydroxide solution after the pH is stabilized; directly oxidizing the M-Na salt to obtain a DM product. The preparation method has the advantages that (1) a hydrogen peroxide stabilizer is added, so that the oxidation of the oxidant is improved, (2) no toxic gas is produced in a production process, so that the environmental pollution is less, the operation is easy and the production period is short, (3) a product has white appearance, high purity and a melting point of greater than or equal to 173 DEG C, (4) a small amount of caustic soda liquid is added, so that the product quality and the purity are improved, and (5) separation can be performed without cooling after the reaction is finished, so that the process period is shortened, the energy consumption is reduced and the cost is saved.

Description

technical field [0001] The invention relates to a preparation method for synthesizing dibenzothiazole disulfide (DM) as a rubber accelerator by utilizing hydrogen peroxide, and belongs to the technical field of rubber accelerator DM synthesis. Background technique [0002] Rubber accelerators play a very important role in the rubber vulcanization process, accelerating the reaction between rubber and vulcanizing agents and improving production efficiency. DM is an indispensable auxiliary in the rubber accelerator industry. Regarding the production process of DM, there are also some reports at home and abroad, mainly using 2-mercaptobenzothiazole (M) as the raw material, which is obtained by oxidation with an oxidant. The main oxidants used are nitrous acid, oxygen, chlorine, potassium permanganate, etc., Although the above methods have their own advantages, they produce a large number of by-products, which have a certain impact on the environment, bring a lot of pressure to t...

AI Technical Summary

Problems solved by technology

Regarding the production process of DM, there are also some reports at home and abroad, mainly using 2-mercaptobenzothiazole (M) as raw material, and oxidizing it with oxidants. The main oxidants used are nitrous acid, oxygen, chlorine, potassium permanganate, etc. Although the above methods have their own advantages, they produce a large number of by-products, which have a certain impact on the environment and bring great pressure to the water treatment project. The process conditions are not easy to control and the operation is complicated.

[0003] Literature (Advances in Fine Petrochemical Industry, 2006, 7(9): 35) reported the oxidation of M with hydrogen peroxide and the preparation of DM with isopropanol as a carrier. Isopropanol can be recycled. , reduce the pressure on environmental pollution, but increase the mother liquor separation process, the distillation of the mother liquor requires a lot of energy, increase the production cost, the process is complicated, and it is not easy to operate

The patent (200710016805.5, 2007-7-9) reported that after dissolving M with ammonia water or liquid ammonia, the ammonium salt solution was obtained and filtered, and a catalyst was added to react with oxygen or air at a certain temperature and pressure for a certain period of time to obtain DM products. This process The method is complicated to operate, the ammonium salt solution needs to be filtered, the whole process needs a catalyst, and the ammonia nitrogen content in the wastewater is high

The patent (200810183218.X, 2008-12-16) reported that the mixture of hydrogen peroxide and sulfuric acid was used as the oxidant to directly oxidize the sodium salt of 2-mercaptobenzothiazole at 55-65°C. When the pH was stable at 6.5-7.5, the reaction At the end, the solid-liquid separation is carried out at a controlled temperature of about 30°C to obtain the product DM. This process is simple to operate and less polluting, but it also has shortcomings. The oxidant is easy to decompose, the oxidation temperature is low, the material is high in viscosity, and it is not easy for solid-liquid separation. After the reaction, the temperature must be lowered to about 30°C before separation, which prolongs the reaction cycle and causes energy waste during the cooling process