Process method for preparing chlorosulfonyl isocyanate through continuous reactive distillation

Abstract

The invention provides a process method for preparing chlorosulfonyl isocyanate through continuous reactive distillation, and relates to the technical field of fine chemical engineering, and the process method comprises the following steps: enabling sulfur trioxide and cyanogen chloride to enter a reactor for primary reaction; continuously feeding the reaction liquid into a first reactive distillation tower, extracting heavy components from the bottom of the tower, extracting sulfur trioxide and cyanogen chloride which do not react completely from the top of the tower, and extracting a chlorosulfonyl isocyanate crude product liquid containing a small amount of chlorinated pyrosulfonyl isocyanate after preliminary concentration from a side liquid phase; continuously feeding the crude product liquid into a second reactive distillation tower, extracting a small amount of sulfur trioxide and cyanogen chloride generated by decomposing chlorinated pyrosulfonyl isocyanate from the top of thetower, extracting a small amount of heavy components from the bottom of the tower, and extracting a qualified chlorosulfonyl isocyanate product from a side gas phase. The preparation efficiency of thechlorosulfonyl isocyanate is improved.

Description

technical field [0001] The invention relates to the technical field of fine chemicals, in particular to a process for preparing chlorosulfonyl isocyanate through continuous reactive distillation. Background technique [0002] Chlorosulfonyl isocyanate is a more active type of isocyanate. It has isocyanate groups, so it can undergo addition reactions with compounds such as hydroxyl, amino, and carboxyl groups to form compounds such as carbamates, ureas, and amides. Because it also contains a sulfonyl chloride group, no matter itself or the reactant after the reaction, as long as it has this group, it can undergo a series of reactions to obtain new compounds. [0003] The production of chlorosulfonyl isocyanate generally adopts the method of reacting sulfur trioxide and cyanogen chloride. When the molar ratio of the two is different, different reaction products can be obtained. For example, when the molar ratio of sulfur trioxide to cyanogen chloride is 1:1, chlorosulfonyl is...

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Problems solved by technology

This just causes great difficulty to separating the chlorosulfonyl isocyanate with higher mass fraction, the traditional production process extracts the chlorosulfonyl isocyanate product at the top of the tower, while extracting the product, the by-product will decompose to generate sulfur trioxide again, The boiling point of sulfur trioxide is much lower than the boiling point of chlorosulfonyl isocyanate, so that sulfur trioxide will be extracted from the top of the tower and chlorosulfonyl isocyanate at the same time, resulting in that the content of sulfur trioxide in the product chlorosulfonyl isocyanate cannot be effectively obtained. reduction of

Therefore, the traditional distillation method is difficult to realize the effective control of the production index of chlorosulfonyl isocyanate

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