A crystallization process for 2-methyl-4-amino-5-(thiocarbamoylthio) pyrimidine sodium salt

Abstract

This invention pertains to the field of intermediate purification technology in vitamin B1 production, specifically to a crystallization process for 2-methyl-4-amino-5-(thiocarbamoylthio) pyrimidine sodium salt. The process comprises the following steps: mixing an aqueous solution of aminopyrimidine with carbon disulfide, initiating stirring, and maintaining the system temperature at 28°C; adding a 30% mass fraction of sodium hydroxide solution dropwise at a rate of 1.5g / min, maintaining the system pH at 10.2 during the addition, and maintaining the reaction for 1.5 hours after the addition is complete; by establishing a synergistic system of solvent selection, temperature control, and reaction conditions, this invention effectively cuts off the impurity transfer pathway, significantly enhances the extraction yield and purity of the intermediate, and simultaneously reduces the content of key impurities, ensuring high-quality production of downstream thiamine and thiamine nitrate. Compared to traditional processes, the product quality stability is greatly improved. Translate into patent document.