Sandwich like poly(ionic liquid)s functionalized microspheres: Efficient interfacial catalysts for preparation of biodiesel

Smart photo-responsive nanospheres azo-p(St-TMGILs)-OEt with sandwich like structure were prepared by introducing alkaline ionic liquids (TMG ILs) and a pioneering photo-responsive monomer (azo-TEPIC) on the surface of polystyrene microspheres by one-pot soap-free emulsion polymerization with free radical polymerization. Then the as-prepared nanoparticles were used as interfacial catalysts for constructing Pickering emulsions, wherein, azo-TEPIC was first obtained by using organosilane to functionalize azobenzene. Pickering emulsions can be reversibly switched between emulsification and breakage by alternate exposure to UV and visible light. The Pickering emulsion was used for the transesterification of soybean oil and ethanol to produce biodiesel and was found to give yields above 97% under mild reaction conditions with superior cycling stability of the catalyst.