A kind of dehydration process of sodium sulfide polyhydrate in the synthesis of polyphenylene sulfide

Abstract

The invention discloses a dehydration process of multi-water sodium sulfide during polyphenyl thioether resin synthesis. The dehydration process comprises the following steps of heating and stirring the multi-water sodium sulfide, a catalyst and an NMP (N-Methyl Pyrrolidone) solution in a reaction kettle in the dehydrating stage of the raw material multi-water sodium sulfide, continuously increasing temperature to 150-200 DEG C, and introducing nitrogen. The dehydration process disclosed by the invention can reduce the dewatering time of the multi-water sodium sulfide in the synthetic process of polyphenyl thioether, increase the dehydration efficiency, reduce the energy consumption, prevent the problems of easiness for decomposition and oxidation and the like of NMP (N-Methyl Pyrrolidone) and sodium sulfide at high temperature in air, generate extremely less NMP gas and other foreign gas in the dehydration process, can be used for carrying away the nitrogen through water vapors and is simplified in process flow and favorable to industrialized production and environmental protection.

Description

technical field [0001] The invention relates to the technical field of polyphenylene sulfide synthesis, in particular to a dehydration process of polyhydrate sodium sulfide in the synthesis of polyphenylene sulfide. Background technique [0002] At present, most of the synthesis of polyphenylene sulfide is obtained by dehydration, polycondensation and other process steps using p-dichlorobenzene and sodium sulfide as raw materials. Due to the strong water absorption of sodium sulfide, it is difficult to preserve, and the price of anhydrous sodium sulfide is expensive and the cost is very high. Therefore, sodium sulfide containing crystal water is generally used in the synthesis process of polyphenylene sulfide, that is, sodium polyhydrate. , so it is necessary to dehydrate sodium polyhydrate before synthesizing polyphenylene sulfide. The conventional dehydration method is to establish a special dehydration facility for dehydration, which not only increases the investment cos...

AI Technical Summary

Problems solved by technology

The conventional dehydration method is to establish a special dehydration facility for dehydration, which not only increases the cost of additional equipment investment, but also greatly increases the energy consumption

[0003] The Chinese invention patent application with application number 201110199757.4 introduces the polyhydrate sodium sulfide dehydration technology in the production of polyphenylene sulfide. It heats the reaction system containing sodium sulfide, N-methylpyrrolidone and co-solvent sodium acetate. Due to the long dehydration time , Dehydration temperature is high, sodium sulfide exposed to the air will react to produce sulfur dioxide, hydrogen sulfide and other toxic gases, and because the heating temperature is higher than the boiling point of N-methylpyrrolidone solution, more N-methylpyrrolidone will be absorbed Therefore, after the gas is discharged from the reactor, it needs to be separated by rectification. The whole process has the defects of long dehydration time, high energy consumption and low efficiency.

The Chinese invention patent application with the application number 201110229726.9 introduces a dehydration process of polyhydrated sodium sulfide in the synthesis process of polyphenylene sulfide resin. Distillation and separation are required, which requires additional equipment costs, long dehydration time, high energy consumption, and low efficiency

[0004] In summary, the existing dehydration process of polyhydrated sodium sulfide is difficult to be popularized and applied in industrial production. It is necessary to improve the existing technology and develop a dehydration process that does not need to increase equipment costs, has short dehydration time, high efficiency, and low energy consumption. Dehydration process to facilitate industrial production

[0005] In order to overcome the technical problems described above, the present invention provides a dehydration process of sodium polyhydrate sulfide in the synthesis of polyphenylene sulfide, so that the dehydration time of sodium polyhydrate sulfide in the synthesis of polyphenylene sulfide is reduced, energy consumption is reduced, and the efficiency is improved. Improve and solve the problem that N-methylpyrrolidone (NMP) and sodium sulfide are easily decomposed and oxidized at high temperature and in the air, the process flow is simplified, and it is beneficial to industrial production and environmental protection