Well-defined core-shell nanostructural block copolymer supported recyclable Bronsted acidic ionic liquid catalyst for the synthesis of biodiesel

A series of Bronsted acidic ionic liquid catalysts was synthesized by anchoring 1-(3-sulfopropyl)pyridinium trifluoromethanesulfonate onto the stable core-shell micelles, which were formed by cross-linking various chain length ratios PS-b-P4VP in toluene with 1,4-dibromobutane. These catalysts display excellent catalytic activity in the esterification or transesterification of palmitic acid or glycerol tripalmitate with methanol or ethanol to synthesize the biodiesel (yield > 99%) in the presence of 4 mol% catalyst loading. Furthermore, the biodiesel yield was maintained about 90% even with a water content of 10 wt% corresponding to the total weight of reaction system. More importantly, these supported catalysts with core-shell structure could be recycled for 5-6 times (5 cycles: yield 89.3%, 6 cycles: yield 84%) only by simple centrifugation without appreciating activity decrease.