| 摘要 |
PURPOSE:To prepare the titled high quality compound in high yield without requiring treatment of waste water, by reacting o-phenylenediamine with carbon disulfide in an aqueous medium in the presence of sodium sulfide or sodium hydrosulfide. CONSTITUTION:In preparing 2-mercaptobenzimidazole by reacting o-phenylenediamide (OPD for short) with carbon disulfide in an aqueous medium (preferably water), the reaction is carried out in the presence of sodium sulfide or sodium hydrosulfide in a molar ratio of it to OPD of 0.5-1.5, preferably 1-1.2. Mother liquid of the reaction of sodium sulfide or sodium hydrosulfide is reusable, discharge of the mother liquid is not required, so treatment of pollution is not needed. Hydrogen sulfide prepared as a by-product is treated at the outside of the system, it contains no impurities such as organic substance, etc. and is recoverable as high-purity sodium hydrosulfide.
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