Catalyst-free biphasic oxidation of Thiophenes in continuous-flow

A mild and practical oxidation process of thiophene derivatives in continuous-flow has been developed. The oxidant phase consists of mCPBA and acetonitrile, which formed an immiscible liquid-liquid segmented flow with the fuel phase. In the oxidation of thiophenes, high yields of sulfone could be realized with only 10 min of residence time in the microreactor. The oxidant phase can be separated with the fuel phase with a continuous membrane separator, rendering it a clean and potentially scalable method to facilitate fuel refining.