Transesterification of methylsulfate and ethylsulfate ionic liquids—an environmentally benign way to synthesize long-chain and functionalized alkylsulfate ionic liquids

A new environmentally friendly method to synthesize long-chain and functionalized alkylsulfate ionic liquids is reported. The two-step synthesis comprises the synthesis of a methylsulfate or ethylsulfate ionic liquid by direct alkylation in the first step. In the second step, this intermediate is transformed in a transesterification reaction, using different functionalized and non-functionalized alcohols, to the corresponding new alkylsulfate melts. The entire reaction sequence is halide-free and liberates methanol or ethanol as the only by-products. Moreover, it is carried out in a solvent-free manner and scale-up is straight forward.