A kind of recovery method of solvent nmp in polyphenylene sulfide resin production process

Abstract

The invention relates to a method for recycling a solvent NMP in a polyphenylene sulfide resin production process. The method for recycling the solvent NMP in the polyphenylene sulfide resin production process comprises the following steps: (1) carrying out solid-liquid separation on a mixture obtained after polymerization reaction on polyphenylene sulfide is finished, so that a polyphenylene sulfide resin product containing oligomer, a byproduct salt and most solvent NMP solutions are respectively obtained; (2) carrying out filter pressing and purification on the obtained solvent NMP solution, so that an NMP solution is obtained; (3) reversely soaking and rinsing the polyphenylene sulfide resin product containing oligomer and the byproduct salt, so that polyphenylene sulfide resin, the byproduct salt and washing liquor are respectively obtained; (4) washing and separating the polyphenylene sulfide resin and the byproduct salt, so that a cleaning solution and a wet polyphenylene sulfide product are respectively obtained, and the wet polyphenylene sulfide product is dried to obtain a qualified polyphenylene sulfide resin product; (5) separating the washing liquor and the cleaning solution, so that an NMP salt solution and viscous materials are respectively obtained; (6) desalting the NMP salt solution, and cooling to obtain mixed liquid containing NMP; and (7) drying the viscous materials, and cooling to obtain NMP. The method for recycling the solvent NMP in the polyphenylene sulfide resin production process is simple and efficient.

Description

technical field [0001] The invention relates to the technical field of organic solvent recovery, in particular to a method for recovering solvent NMP in the production process of polyphenylene sulfide resin. Background technique [0002] Using sodium sulfide (Na 2 S·H 2 O) and p-dichlorobenzene (P-DCB) as raw materials, in the process of polycondensation production of polyphenylene sulfide (PPS) resin under the action of alkali metal and lithium salt additives, alkali metal and lithium salt are required in the polymerization stage NMP (N-methylpyrrolidone) solution completes the catalysis. Compared with the cost of other raw materials, NMP lithium salt solvent occupies a considerable price proportion, but the solvent NMP and additives are theoretically not consumed in the production process of PPS. Therefore, whether the solvent NMP and additives can be recovered with a higher recovery rate is the key to reducing the production cost of PPS. [0003] After the polymerizati...

AI Technical Summary

Problems solved by technology

[0006] In the Chinese patent CN001161423, a solvent and co-solvent recovery technology in the production of polyphenylene sulfide is introduced. This technology uses carbonate to recover the so-called catalyst. The catalyst recovery is very low, generally between 5~10%wt, and Recycled additives cannot be reused at all

[0007] Due to the serious loss of solvent NMP in the traditional production of polyphenylene sulfide, the recovery rate of solvent NMP for polyphenylene sulfide produced by most domestic and foreign enterprises should preferably reach 60% %, and some companies even have a lower NMP recovery rate due to equipment, equipment technology and other reasons. Because the market price of NMP is relatively expensive (the current domestic price is more than 20,000 yuan / ton), the cost of producing PPS has doubled, and this It is a serious real problem faced by most enterprises