Preparation method of sulfur bridge-containing reverse ester thiol methyltin

Abstract

The invention discloses a preparation method of sulfur bridge-containing reverse ester thiol methyltin. The method comprises two stages: in a first stage, preparing mercaptoethanol oleate, and controlling the vacuum degree in a first reaction container to descend stepwise in a reacting process; and in a second stage, preparing sulfur bridge-containing reverse ester thiol methyltin by taking mercaptoethanol oleate obtained at the first stage as a raw material, dropwise adding a methyl tin chloride aqueous solution and a sodium sulfide aqueous solution into the mercaptoethanol oleate simultaneously, and undergoing a condensation reaction and a bridging reaction simultaneously to control sulfur atoms in sodium sulfide and tin atoms in methyl tin chloride to be connected in a sulfur bridge form. The preparation method is easy to implement, the problems of emulsification, saponification and the like in a production process can be solved effectively, and the productivity and production efficiency are increased; and meanwhile, the ratio of a sulfur bridge is controlled, so that the thermal stability of a product is in an optimal state.

Description

technical field [0001] The invention relates to the technical fields of production of plastic additives and plastic processing, in particular to a preparation method of methyl tin mercaptide containing a sulfur bridge. Background technique [0002] Among the many PVC heat stabilizers, methyl tin mercaptide is recognized as a heat stabilizer with good effect in the industry. In the 1950s, the United States patent document US 2731484 mentioned the production and potential use of dialkyl tin mercaptide; from the early 1980s, methyl tin mercaptide began to be produced and applied on a large scale; in 1989, my country's first large-scale production line of methyl tin mercaptide was built in Hubei Nanxing Chemical General Factory. After more than 20 years of development, my country now has nearly 70% of the world's production and sales of methyl tin mercaptide. [0003] Usually, methyl tin mercaptide has the following general structural formula: (CH3) X Sn[S(R 1 ) MCOOR 2 ] 4-...

AI Technical Summary

Problems solved by technology

[0013] 1. In the process of producing mercaptoethanol oleate, the raw materials include oleic acid and mercaptoethanol. Since the two are heated during the reaction, a large amount of mercaptoethanol will be evaporated, and considering that mercaptoethanol is much more expensive than oleic acid, so In the prior art, the usage amount of oleic acid is more than the usage amount of mercaptoethanol, yet, the usage amount of oleic acid is more can cause the poor quality of product;

[0014] 2. Both U.S. Patents US4120845 and US5821274 mentioned that methyl tin chloride and mercaptoethanol oleate were first condensed to generate hydrogen chloride, and then hydrogen chloride was neutralized with aqueous sodium hydroxide solution, and then sodium sulfide was added dropwise for bridging Reaction, in recent years, domestic manufacturers have also followed this idea, but this process cannot guarantee that the Sn-S-Sn bridging structure will be formed according to the set ratio, resulting in the product being easily emulsified, difficult to wash and stratify, and the reactant is easy to turn black , at the same time, hydrogen sulfide may be generated during the production process

Images