Esterification of levulinic acid in the production of fuel additives catalyzed by porous sulfonated carbon derived from pine needle

Pine needle derived porous sulfonated carbon is facilely synthesized and subsequently applied in the levulinic acid (LA) esterification with ethanol. Various preparation parameters are optimized to improve the catalytic efficiency. The resulting heterogeneous catalysts possess a hierarchical porous structure and a high acidic density of 2.08 mmol g⁻¹, leading to their high activity and superior recyclability. Under the present conditions, the initial activity is maintained as high as 91.3% even after six runs. This work verifies the porous biomass-derived sulfonated carbon are highly promising catalysts for the environmentally benign synthesis of ethyl levulinate fuel additive.