Method for measuring content of antimony in methyltin mercaptide composite heat stabilizer through indirect iodometric method

Abstract

The invention relates to a method for measuring content of antimony in a methyltin mercaptide composite heat stabilizer through an indirect iodometric method. The method comprises the following steps that firstly, a certain amount of methyltin mercaptide composite heat stabilizer samples are weighed, concentrated sulfuric acid, concentrated nitric acid and perchloric acid are sequentially added, the volume proportion of the concentrated sulfuric acid to the concentrated nitric acid to the perchloric acid is (2-3):1:1, the proportion of the sample mass to the mixed acid volume is 1: (35-55) g / ml, heating and dissolving are carried out, after the mixture is cooled to the room temperature, a (1+9) hydrochloric acid solution is added for constant volume V, and the mixture is shaken evenly to be used; secondly, the volume V0 of the solution prepared in the first step is moved and taken, a proper amount of potassium iodide and starch indicator are added, a sodium thiosulfate standard titration solution with the molar concentration being 1.000 mol / L is used for titration until the solution becomes colorless from blue so that a titration terminal can be achieved, the volume V1 of the consumed sodium thiosulfate standard titration solution is recorded, meanwhile, a blank test is made, volume V2 is recorded, and the antimony content is calculated according to formula 1 shown in the description. By means of the method, testing results are accurate and reliable, expensive special analytical instruments are not needed, the cost is low, and the method is easy to apply and popularize.

Description

technical field [0001] The invention relates to a method for measuring the antimony content of a methyl tin-antimony composite heat stabilizer for PVC, in particular to a method for measuring the antimony content in the methyl tin-antimony composite heat stabilizer by indirect iodometric method. Background technique [0002] The authorized patent ZL201010254909.1 applied by Zhejiang Hepton New Materials Co., Ltd. has prepared a methyl tin antimony liquid composite heat stabilizer through compounding technology. The main components are methyl tin mercaptide, antimony mercaptide and auxiliary auxiliary agent. The product improves the initial and long-term thermal stability of PVC products and the transparency of products, improves the processing rheological properties of PVC products, prolongs the production cycle, protects equipment, reduces the tin content in methyl tin heat stabilizers, reduces the consumption of rare metal tin and It pollutes, reduces the cost of methyl t...

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Problems solved by technology

[0004] Chinese patent CN103969396B describes "a method for detecting antimony content in liquid products". This invention includes two parts: the dissolution preparation and verification of liquid samples. The potassium bromate titration method is mainly used to test the content of antimony, which has complicated sample processing and slow reaction speed. , the titration end point is difficult to judge and other shortcomings

The methyl tin antimony composite heat stabilizer belongs to high molecular organic matter, and hydrochloric acid and potassium sodium tartrate are difficult to dissolve the methyl tin antimony composite heat stabilizer, so the detection of the antimony content in the methyl tin antimony composite heat stabilizer cannot be realized

Therefore, there is still no applicable detection method for measuring (high molecular organic matter) antimony content in the methyl tin antimony liquid composite stabilizer

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