Highly Efficient SO۳H-Carbon Catalysed Solvent-Free Synthetic Protocol for Wax Esters Via Esterification of Long Chain Fatty Acids and Alcohols

Solvent-free synthesis of saturated and monounsaturated wax esters (WEs), ۳a-j with carbon chain ranging from C۲۶ to C۳۸ was successfully demonstrated through esterification of long chain fatty acids (LCFAs), ۱a-g (C۱۰:۰, C۱۲:۰, C۱۶:۰, C۱۸:۰, C۱۸:۱, C۱۸:۱,۱۲-OH, C۲۲:۰, and C۲۲:۱ acids) with long chain fatty alcohols (LCFAlc), ۲a-d (cetyl (C۱۶), stearyl (C۱۸), behenyl (C۲۲) and erucyl (C۲۲:۱) alcohols) by SO۳H-carbon catalyst derived from glycerol. The optimized reaction conditions for the efficient synthesis of WEs with excellent conversion and selectivity recorded in solvent free system are: ۲۰ wt.% of SO۳H-carbon catalyst, reaction time of ۶-۱۰ h, temperature of ۹۰ °C and substrate (LCFA:LCFAlc) molar ratio of ۱:۱. All the synthesized WEs were purified by silica gel column chromatography and characterized by FTIR, ۱H-NMR, and GC-MS spectral studies. In addition, this methodology involves simple workup protocol, without use of dean stark or dehydrating agents compared to the reported homogeneous/heterogeneous catalysed methods. Furthermore, the resulting synthetic WEs can play a potential alternates for the commercial products extracted from natural sources of lesser availability, thus making this SO۳H-carbon catalysed route very promising for further potential industrial implementation.