|Accelerator Chemical Name|
Initial M.P. (Min) ≥ °C
Loss on drying (Max) ≤ %
Ash (Max) ≤ %
Residues on 150μm sieve, % ≤
Oil content, %
Granular diameter mm
DPG is one of the most important rubber vulcanization promoters, which is mainly used in natural and synthetic rubber.It has good aging resistance in vulcanized rubber and also ACTS as an activator of thiazole, thiuram and sulfonamide promoters.In the chloroprene rubber has the plasticizer, the plasticizer the function, is also produces the dye the raw material, the plastic product crosslinking agent, the temperature material and the building materials use the auxiliary agent and so on, mainly USES in the manufacture tire and the rubber product and so on rubber sole.
The main production processes of promoter DPG include cyanide chloride, metal oxide desulfurization and oxidation desulfurization.Among them, catalytic oxygen oxidation is the most suitable process for green chemistry.
At present, the industrialization methods of rubber vulcanization promoter DPG are using oxygen as oxidant, under the catalysis of copper acetate catalyst, the raw material diphenyl thiourea (CA) ammonia is oxidized to generate the promoter DPG.Specifically, (1) preparation of diphenyl thiourea by first mixing aniline with water and then reacting with carbon disulfide and sulfur;(2) diphenyl thiourea was mixed with water, ammonia was added, oxygen was passed through, and diphenyl guanidine was obtained by catalytic oxidation reaction.(3) the product is then dissolved in acid to filter out the dregs. Then the liquid alkali is used to precipitate and filter the product. Then a large amount of salt in the product is washed with a large amount of water.This method is a relatively traditional one. In order to ensure the conversion rate of CA in the production process, excessive ammonia water is generally required. In the production process, ammonia gas and oxygen are easy to form explosive mixture, which poses a great safety risk.At the same time, in order to speed up the reaction speed, the production process needs to provide a certain amount of pressure, the pressure resistance of the equipment is also required, the long-term operation process of the equipment requirements are high, the industrialization investment is large.
In addition, at present, the synthesis process of promoter DPG mainly adopts kettle type reactor for batch operation, and the batch is greatly affected by personnel operation, so the product quality is prone to instability.At the same time, during the kettle oxidation process, the amount of ammonia feed is large, and the unreacted ammonia and oxygen are easy to form explosive mixture, which increases the process risk.At the same time, the manufacture cost of pressure reactor is high, and it is easy to have problems in long-term operation.
Microchannel reactor has a large specific surface area, fast mixing, high mass transfer efficiency of heat transfer, reaction conditions of uniform and has attracted many attentions of the researchers in the field of chemical synthesis, its high mass transfer, heat transfer efficiency to make a lot of reaction can realize accurate control, and then to the theory of instantaneous reaction, to increase the efficiency of the product in the process of synthesis, process safety and product quality has a great help.
The method of continuous production of vulcanization accelerator DPG needs further research.