Chemical fixation of CO2: the influence of linear amphiphilic anions on surface active ionic liquids (SAILs) as catalysts for synthesis of cyclic carbonates under solvent-free conditions

Abstract

Carbon dioxide (CO2) conversion is an efficient option to mitigate environmental impacts caused by CO2 high concentration in the atmosphere. In this work are described catalytic activities of surface active ionic liquids (SAILs) composed of well-known cations 1-butyl-3-methylimidazolium ([bmim+]) and tetra-n-butylammonium ([TBA+]) and long alkyl chain anions: lauryl sulfate ([C12SO4−]), lauryl ether sulfate ([C12ESO4−]), lauryl benzene sulfonate ([C12BSO3−]) and lauroyl sarcosinate ([C12SAR−]) for cyclic carbonate synthesis. Results evidenced that [TBA+] is more active as a catalyst due to its higher molecular volume increasing the cation–anion distance and weakening the electrostatic interaction resulting in a more electrophilic cation. The [TBA][C12BSO3] SAIL presented better catalytic activity for styrene carbonate (SC) synthesis, reaching 81.4% of conversion and 87.0% of selectivity as well as the high recycle capacity and possible application as catalyst for the syntheses of different cyclic carbonates: glycidyl isopropyl ether carbonate (GC) and epichlorohydrin carbonate (EC).