Abstract: A preparation method of a polyphenylene sulfide resin, and a polyphenylene sulfide resin prepared by the method using a sulfur-containing compound, an alkaline substance and p-dichlorobenzene as raw materials, a fatty acid as a polycondensation aid to carry out a polycondensation reaction. After purification treatment, a primary polyphenylene sulfide is obtained, which then reacts with a terminal-group adjusting agent at a high temperature to generate the polyphenylene sulfide resin resulting in high yield and low cost. The prepared polyphenylene sulfide resin has high reactivity, high melting crystallization temperature and excellent thermal stability. The resulting polyphenylene sulfide resin can be directly used for extrusion and injection molding.

Abstract: The present disclosure discloses a preparation method for 4-phenylthio-benzenethiol. The preparation method comprises the following steps: subjecting phenyl sulfide as a raw material to a halogenation reaction to obtain 4-halophenyl sulfide; subjecting the 4-halophenyl sulfide to a sulfhydrylation reaction to obtain a 4-phenylthio-phenylthiolate; and subjecting the 4-phenylthio-phenylthiolate to acidification. The preparation method of the present disclosure avoids the use of materials such as thiophenol which pollutes the environment, and realizes efficient recycling of the reaction materials, solvents, water and the like. The preparation method of the present disclosure is a green process for the synthesis of 4-phenylthio-phenylthiol without organic waste, waste acid and waste water discharge.

Abstract: The present disclosure discloses a preparation method for 4-phenylthio-benzenethiol. The preparation method comprises the following steps: subjecting phenyl sulfide as a raw material to a halogenation reaction to obtain 4-halophenyl sulfide; subjecting the 4-halophenyl sulfide to a sulfhydrylation reaction to obtain a 4-phenylthio-phenylthiolate; and subjecting the 4-phenylthio-phenylthiolate to acidification. The preparation method of the present disclosure avoids the use of materials such as thiophenol which pollutes the environment, and realizes efficient recycling of the reaction materials, solvents, water and the like. The preparation method of the present disclosure is a green process for the synthesis of 4-phenylthio-phenylthiol without organic waste, waste acid and waste water discharge.

Abstract: The present disclosure provides a production method of a semi-aromatic polyamide, and a semi-aromatic polyamide. Said production method of a semi-aromatic polyamide includes: step 1 of subjecting an initial charge of a diamine and a binary acid in an amine/acid molar ratio of less than 1.0 to form a slurry together with water and a catalyst, and subjecting the slurry to heating and dissolution to form a saline solution; step 2 of dehydrating said saline solution after detecting the composition thereof, detecting the content of diamine in a steam condensate from a dehydration unit, adjusting the amine/acid molar ratio to be larger than 1.0 by a molten diamine and a monoacid as a molecular weight regulator, and performing pre-polymerization; and step 3 of subjecting a pre-polymerization solution to post-polycondensation after vacuum flashing. The semi-aromatic polyamide of the present disclosure has a low gel content, excellent performance and extensive scope of application.

Abstract: The present invention discloses a fiber-grade polyphenylene sulfide resin synthesis method, taking sodium bisulfide and p-dichlorobenzene as raw materials, N-methyl pyrrolidone as the solvent and C5-C6 fatty acid salt formed through dehydration to C5-C6 fatty acid and sodium hydroxide as the polymerization additive for synthesis through polymerization. White polyphenylene sulfide resin is obtained through acidification and washing of reaction slurry. In view of the fact that MFR is below 125 g/10 min, weight-average molecular weight as measured by GPC is over 4.2×104, and whiteness is over 90, it can satisfy requirements for fiber polyphenylene sulfide resin. C5-C6 fatty acid salt according to the method of the present invention has a higher solubility in NMP, which can better promote polymerization. It is to be fully diverted into the filtrate after filter prior to conversion into free fatty acid again through acidification with hydrochloric acid.