Dimethyl sulphur-based ethylene synthesis method

Abstract

The invention provides a dimethyl sulphur-based ethylene synthesis method. In the method, potassium hydroxide which has grain size at the range of 100 to 300 nm is replaced by nano potash to serve as a raw material to react. The method comprises the following steps: adding the raw materials of carbon disulfide, nitromethane or malononitrile, the nano potash and solvent into a reactor to react; filtering after complete reaction to obtain brick red solid, carrying out atmospheric distillation on filtrate and recovering the solvent; dissolving the brick red solid in water, slowly adding dimethyl sulfate while stirring; filtering after complete reaction; and recrystallizing the solid with ethanol to obtain buff solid 1,1-dimethyl sulfur-2-nitroethyleneor or 1,1-dimethyl sulfur-2,2-dicyano ethenyl. In the method, strong base potassium hydroxide is not used, and the method has moderate reaction condition and hardly any side reaction, and is simple and convenient in operation.

Description

technical field [0001] The invention relates to a synthesis method of dimethylthioethylene, in particular to a synthesis method for synthesizing 1,1-dimethylthio-2-nitroethylene and 1,1-dimethylthio-2,2-dicyanoethylene. Background technique [0002] 1,1-dimethylthio-2-nitroethylene and 1,1-dimethylthio-2,2-dicyanoethylene are two important chemical intermediates, widely used in the synthesis of medicines and pesticides. [0003] At present, 1,1-dimethylthio-2-nitroethylene is synthesized by KOH method: first, nitromethane and carbon disulfide are added to the reactor, and KOH ethanol solution is slowly added at 20-50°C. After the addition, react at 50°C for a period of time, cool and filter to obtain brick red solid 1,1-dipotassium thio-2-nitroethylene (commonly known as dipotassium salt). Then dissolve 1,1-dipotassium thio-2-nitroethylene in water, react with dimethyl sulfate at 10-30°C, and filter to obtain the crude product 1,1-dimethylthio-2-nitroethylene , recrystalli...

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Problems solved by technology

[0005] The weak point of above-mentioned method: 1) when dripping KOH ethanol solution, reaction is particularly violent, needs just to carry out reaction smoothly under ice-salt water cooling; 2) KOH not only reacts with nitromethane, also takes place strong side reaction with carbon disulfide, and side reaction is many, The product yield is less than 50%; 3) Wastewater contains a large amount of organic by-products, causing serious environmental pollution

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