Iron containing di-cationic ionic liquid [DIL]2+[2FeCl4]2− as a highly efficient catalyst for the acylation of alcohols, phenols and amines

Abstract

In this study, we describe the synthesis of an efficient catalyst for the acylation of alcohols, phenols, and amines in the presence of 3,3′-(ethane-1,2-diyl)bis(1-methyl-1H-imidazol-3-ium) tetrachloroferrate [DIL]2+[2FeCl4]2− and acetyl chloride (acylating reagent). Remarkably, when exposed to 7 mol% of catalyst [DIL]2+[2FeCl4]2− in a solvent-free environment, acetyl chloride demonstrated excellent acylation activity in a shorter period of time. As a result, a generic approach for the acylation of alcohols, phenols, and amines has been developed. As an ionic liquid, [DIL]2+[2FeCl4]2− can be easily recovered and reused up to five times in a row with little loss of catalytic activity. TGA and DSC analyses were also performed to determine the thermal robustness of [DIL]2+[2FeCl4]2−. We were able to illustrate the several advantages of this acylation approach. It provides better yields in less time and opens up the possibility of a safe, environmentally friendly remedy for acylation reaction.