Synthesis of biochar modified with 12-tungstophosphoric acid for the selective conversion of isoeugenol to vanillin

Abstract

A heterogeneous acid catalyst was synthesized by anchoring 12–tungstophosphoric acid (HPW) onto biochar derived from Brazil nut shells (Bertholletia excelsa). This catalyst was used for the synthesis of vanillin from isoeugenol, employing hydrogen peroxide in acetonitrile solvent. The HPW-functionalized biocatalyst was prepared using a sonication method, which avoids the need for toxic and corrosive solvents, effectively incorporating tungsten at a mass proportion of 25%. Characterization of the catalysts utilized various techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and ultraviolet–visible spectroscopy. 30HPW/CC(200–2) exhibited high selectivity for vanillin (55%) with a significant conversion rate (69%). Over four cycles, selectivity and conversion remained consistently above 56% and 45%, respectively. The results presented in this study have the potential to promote a more sustainable vanillin production process, a valuable additive in the food and perfume industries, renowned for its high economic value.

Keywords

• Waste valorization
• Biochar
• Heterogeneous catalysis
• Isoeugenol oxidation
• Vanillin
• Amazon