Waste-to-useful: a biowaste-derived heterogeneous catalyst for a green and sustainable Henry reaction

Owing to the depletion of resources coupled with increasing waste generation, the conversion of waste biomass to value-added materials has gained interest. Here, we report for the first time the application of Musa acuminata (banana) peel ash (MAPA) as a heterogeneous catalyst for C-C bond formation via a Henry reaction under solvent-free conditions at ambient temperature. The catalyst was well characterized using different analytical techniques like FT-IR, SEM, TEM-EDS, XRD, XRF, XPS, BET and TGA, along with basicity determination by a Hammett indicator test and titration method. An excellent yield of nitroalcohol was obtained within 15-30 minutes. No dehydrated product was observed. The catalyst used in these studies has the advantage of being a waste material and is hence low-cost, easily prepared, recyclable and environmentally friendly. In addition, the use of a biogenic renewable catalyst, its atom economy, and room temperature and solvent-free reaction conditions and the avoidance of column chromatography make the protocol highly significant from green and sustainable chemistry perspectives.