Efficient photocatalytic acetalization of furfural to biofuel components using carboxyl-functionalized porphyrin photocatalyst, under visible light irradiations

The carboxyl-functionalized porphyrin entangled with benzimidazolium-based ionic liquid (CFPBIL) was successfully synthesized and characterized by FT-IR, FT-NMR and TGA analysis. The proton level was determined by the Hammett acidity function, and DR spectra have been supported to confirm the band gap of photocatalyst. The present study reveals the metal-free, conventional photocatalytic acetalization of furfural to biofuel components under visible light irradiations using carboxyl-functionalized porphyrin catalyst. The effect of different parameters on the photocatalytic reaction, catalyst loading, ratio of furfural:alcohol, duration and intensity of light were investigated. The model reaction of furfural and ethanol in a home-made photoreactor using a 5-W LED presented that a very high yield of furfural acetal (92%) could be obtained under optimized conditions. Moreover, the eco-friendly method of acetalization reactions with higher alcohols (1-butanol, 1- pentanol, 1-hexanol, 1-octanol) was carried out at optimized reaction conditions which also afforded good to excellent yield of the target products, demonstrating the potential of CFPBIL as a highly active, stable and recyclable heterogeneous photocatalyst. Moreover, physical properties of biodiesel-diesel blends comprising B10, B20 and B30 were determined and furfural acetals were found as a potential fuel additive.