Biodiesel production via esterification of oleic acid catalyzed by Brønsted acid-functionalized porphyrin grafted with benzimidazolium-based ionic liquid as an efficient photocatalyst

The production of ethyl oleate was explored using novel metal-free Bronsted acid-functionalized porphyrin, grafted with benzimidazolium-based ionic liquid (BAPBIL) as a recyclable photocatalyst. The synthesized photocatalyst was characterized by FT-NMR and FT-IR spectroscopy techniques. The esterification reaction was carried out under a homemade photoreactor equipped with a 5 W LED as a visible light source. In this work, BAPBIL displayed as an efficient photocatalyst for esterification of oleic acid and levulinic acid using different alcohols such as methanol, ethanol, propanol, and octanol at ambient conditions. The mechanism of the photocatalyst was studied to confirm the role of the catalyst. Moreover, a scavenger study showed the effect of the scavenger on the rate of esterification of oleic acid. The heterogeneous recyclable photocatalyst (BAPBIL) presented recyclability up to five successive runs without losing its activity. The maximum conversion of the esterification product was achieved at 96% at optimized reaction conditions.