Highly effective solvent free esterification of phytosterols employing edible metal oxide-emulsifier as catalyst

A general highly efficient solvent-free esterification of phytosterols with edible magnesium oxide and Span-60 emulsifier catalyst system has been developed. The edible emulsifier dramatically promotes the catalyzing activity of the metal oxide in the reaction. The loading of the magnesium oxide is as low as 0.1 wt% to phytosterols and far lower than the known ones. As demonstrated by the results of scanning electro-microscopy (SEM), the synergistic effect of emulsifier and magnesium oxide presumably results from elimination of nano-scale interfacial barrier between phytosterols and fatty acids and facilitation of mass transfer of reaction agents. The mild, environmentally benign, and highly effective nature of this catalytic transformation suggests its great potential applications.