| 摘要 |
<p>GW 31828 PROCESS FOR THE PREPARATION OF 2-MERCAPTOBENZOTHIAZOLE A process for the preparation of 2-mercaptobenzothiazole is disclosed. In a first embodiment the process comprises heating a reaction mixture comprising nitrobenzene and hydrogen sulfide in a molar ratio of from about 1:3 to about 1:6, respectively, to a temperature from about 100 to about 170.degree.C, for a time sufficient to substantially reduce the nitrobenzene. Subsequently, the resultant product mixture is reacted with from about 1 to about 3 mol equivalents of carbon disulfide, based on the weight of the originally present nitrobenzene, at a temperature from about 200 to about 300.degree.C for a time sufficient to convert at least a portion of the reactants into 2-mercaptobenzothiazole. Preferably, the water of reaction formed by reacting the nitrobenzene and hydrogen sulfide is removed prior to reacting the resultant product mixture with carbon disulfide. In an alternative embodiment, the process comprises reacting a mixture comprising nitrobenzene, hydrogen sulfide, and carbon disulfide in a molar ratio of about 1:3 to 6:1 to 3, at gradually increasing incremental temperatures which are above about 100.degree.C and below about 170.degree.C until the nitrobenzene is substantially reduced. Subsequently, the temperature is increased to at least about 200.degree.C for a period of time sufficient to convert at least a portion of the reactants into 2-mercaptobenzothiazole.</p> |
