A process for the efficient conversion of trimethylsulfonium methylsulfate into dimethylsulfonium methanide, thence epoxides, has been devised. Thus dimethyl sulfate and dimethyl sulfide are caused to react in the presence of either a mineral acid or an organic acid. The anion of trimethylsulfonium methyl sulfate is converted by the acid into methyl hydrogen sulfate, which in turn reacts with excess dimethyl sulfide to form trimethylsulfonium hydrogen sulfate. The outcome is that both methyl groups of dimethyl sulfate are converted into the desired trimethylsulfonium salt, thence dimethylsulfonium methanide; the process is mediated by low boiling dimethyl sulfide which can be recycled, and the by-product (K2SO4) is more easily disposed of than potassium methyl sulfate.
现已设计出一种将甲基
硫酸三甲锍有效转化为
甲烷化二甲锍,进而转化为
环氧化物的工艺。这样,
硫酸二甲酯和
硫化二甲酯在矿物酸或有机酸的存在下发生反应。三甲基
硫酸甲酯的阴离子被酸转化为
硫酸氢甲酯,
硫酸氢甲酯又与过量的
硫化二甲酯反应生成三甲基
硫酸氢鎓。其结果是,
硫酸二甲酯的两个甲基基团都转化为所需的
三甲基锍盐,进而转化为
甲烷二甲基锍;该过程由低沸点的
硫化二甲酯介导,可以循环使用,而且副产品(K2SO4)比甲基
硫酸钾更容易处理。