Water-saving high-purity monosultap synthesis process

Abstract

The invention discloses a water-saving high-purity monosultap synthesis process, which mainly improves a reaction system of amination reaction in the monosultap synthesis process, adopts pyridine to replace water as the reaction system, and adopts pyridine to replace dimethylamine as an acid-binding agent, thereby enhancing the purity and reaction yield of the prepared N,N-dimethylacrylamide. Meanwhile, as the boiling point of pyridine is far higher than that of dimethylamine, production and recovery are facilitated, and compared with dimethylamine serving as an acid-binding agent, volatilization is little, the production environment is facilitated, and the recovery rate is high; and meanwhile, the total wastewater amount can be reduced to 30%-40% of the wastewater amount of the amination reaction of the traditional dimethylamine aqueous solution system, and the environmental benefit is extremely high.

Description

technical field [0001] The invention relates to a synthesis process of monosultap, in particular to a synthesis process of water-saving and high-purity monosultap. Background technique [0002] Dimehypo, the chemical name is 2-dimethylamine-1-sodium thiosulfate-3-thiosulfate propane, its common preparation method is to obtain dimehypo by excessive alkalization first, and then produce dimehypo through Hydrochloric acid is acidified and crystallized to obtain monosultap, which generally contains one molecule of crystal water, and its structural formula is as follows: [0003] [0004] In the prior art, the most widely used monosultap synthesis process steps are: 1, amination reaction of dimethylamine and chloropropene; 2, acidification with hydrochloric acid; 3, chlorination reaction with chlorine addition; 4, alkaline Sulfonation reaction with sodium thiosulfate under certain conditions; 5. Acidification and crystallization with hydrochloric acid. [0005] Wherein, the g...

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Problems solved by technology

[0007] 1. The amination reaction is a nucleophilic substitution reaction. Due to the presence of a strong polar substance such as water in the reaction system, some side reactions occur, so that the obtained N,N-dimethylacrylamine (CH 3 ) 2 NCH 2 CH=CH 2 The purity is not high and the yield decreases;

[0008] 2. The above-mentioned amination process uses dimethylamine as an acid-binding agent to absorb the HCl produced in the amination process. However, due to the extremely low boiling point of dimethylamine, it is very volatile at 7°C, which causes dimethylamine to The recovery rate is not high during recycling, and it leads to a foul smell in the production environment, which is extremely detrimental to human safety and environmental safety, and makes the utilization rate of raw materials low, and the refrigeration energy consumption during distillation is extremely high;

[0009] 3. Due to the large amount of water introduced by the aqueous solution of dimethylamine, there is a huge amount of waste water after recovering excess dimethylamine

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