Method and device for preparing heptafluoroisobutyronitrile

Abstract

The invention discloses a method and device for preparing heptafluoroisobutyronitrile, wherein the method comprises the steps: adding methyl heptafluoroisobutyrate into a reaction kettle, adding an alcoholic solution of ammonia, and controlling the reaction temperature to be lower than 0 DEG C; carrying out a reaction for 2-5 h, heating to 60 DEG C, finishing the reaction when the content of methyl heptafluoroisobutyrate in a reaction solution is less than 0.1%, removing a methanol solvent by vacuum distillation, and removing the vacuum when the content of methanol in the reaction solution inthe reaction kettle is less than 1%; and adding a dimethylformamide/pyridine solvent into the reaction system, controlling the reaction temperature to be lower than 0 DEG C, adding a dehydrating agenttrifluoroacetic anhydride, and collecting heptafluoroisobutyronitrile gas. According to the method, an intermediate heptafluoroisobutyrylamide synthesis step and a step device for preparing heptafluoroisobutyronitrile by dehydrating heptafluoroisobutyrylamide are integrated; transfer of an intermediate heptafluoroisobutyramide is not needed and water washing, extraction, recrystallization and other operations are avoided, so the heptafluoroisobutyronitrile is directly synthesized, the equipment investment is greatly reduced, the operation process is simplified, and the method is suitable forindustrial production.

Description

technical field [0001] The invention relates to a synthesis device of heptafluoroisobutyronitrile, in particular to a device for synthesizing heptafluoroisobutyronitrile through ammoniation and dehydration of heptafluoroisobutyronitrile. Background technique [0002] Heptafluoroisobutyronitrile is a new type of environmentally friendly insulating gas material. It has the characteristics of low boiling point, high volatility, excellent electrical insulation properties and good environmental performance. It can be used as a dielectric composition for electrical equipment insulators. The greenhouse effect index (GWP) of heptafluoroisobutyronitrile is only 2210, which is much lower than that of sulfur hexafluoride (GWP=23500). It can be used to replace the traditional sulfur hexafluoride insulating gas and greatly reduce the problem of atmospheric greenhouse effect. Heptafluoroisobutyronitrile has received widespread attention from the global electrical industry and has begun to...

AI Technical Summary

Problems solved by technology

During the process, materials need to be transferred and multi-step operations such as washing, extraction, liquid separation, and drying are used. The process is long, the equipment is complicated, and the operation is difficult.

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