Synthesis method of p-toluenesulfonyl semicarbazide foaming agent

Abstract

The invention discloses a synthesis method of a p-toluenesulfonyl semicarbazide foaming agent. The synthesis method comprises the following steps: S1, reducing p-toluenesulfonyl chloride into a p-toluenesulfinate in the presence of an inorganic alkali by using p-toluenesulfonyl chloride as an initial raw material, sodium sulfite as a reducing agent and water as a solvent to obtain a p-toluenesulfinate aqueous solution; and S2, adding azodicarbonamide into the p-toluenesulfinate aqueous solution obtained in the step S1 for a reaction, stopping the reaction when no gas is released, and carryingout cooling, filtering, water washing and drying to obtain a target product, namely the p-toluenesulfonyl semicarbazide, wherein the reaction temperature in the step S2 is 70-90 DEG C, preferably, thereaction temperature in the step S2 is 78-82 DEG C. The synthesis method disclosed by the invention is safe and environmentally friendly, is high in yield, and is simple to operate; the raw materialsare convenient and easy to obtain and are low in cost; and thus the synthesis method is a synthesis route suitable for industrial production.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a synthesis method of p-toluenesulfonylsemicarbazide foaming agent. Background technique [0002] p-toluenesulfonylsemicarbazide is a high-temperature nitrogen blowing agent, which has the characteristics of non-toxicity, small powder particles, good dispersion in polymers, fine and uniform bubbles, and has been widely used in many fields. It is especially suitable for plastics processed at high temperature, such as ABS resin, nylon, rigid PVC, HDPE, PP, PC, etc. It can also be used for foaming of natural rubber and synthetic rubber. Good processing safety, no risk of premature foaming. [0003] At present, there are not many synthetic methods publicly reported in the literature, and there are mainly the following two methods: [0004] Synthetic method one (Chinese patent CN1406663, "Chemical Engineering"): [0005] Reaction equation: [0006] [0007] The first ...

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Problems solved by technology

[0022] 1. In the first step, large-scale industrial production has been carried out, the reaction temperature is high, the yield is low, and a large amount of three wastes (ammonia gas, nitrogen-containing wastewater and polymer solid waste) are produced in the production process, and the market price of raw materials is also very expensive

[0023] 2. Hydrazine hydrate is a dangerous chemical that is prone to explosion, and there are great safety hazards in the production process

[0024] 3. Since the yield in the first step is only 62%, the total yield is low, there are many by-products, and the synthesis cost is high

[0025] There are many problems in the above two synthetic methods, and they are not suitable for industrial production.

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