Upgrading the Brønsted acidity of zeolite Hβ via phosphotungstates: engineering a high-performance catalytic platform for the production of energy-efficient biofuel additives

Abstract

This investigation reports an environmentally benign approach to meet the current paradigm of synthesizing fossil fuel alternatives, contributing to a sustainable future. For this, a novel catalytic material designed to advance both chemical science and sustainable technology has been engineered. A systematic strategy has been employed to upgrade the Brønsted acidity of zeolite Hβ through the incorporation of 12-tungstophosphoric acid, providing a heterogeneous catalyst whose structural, acidic, and textural features have been established via physicochemical characterization. It is applied for the first time in the esterification of highly promising bioplatform molecules, levulinic acid and succinic acid, and exhibits significant selectivity toward the production of butyl levulinate (99%) and dibutyl succinate (82%), both of which are recognized as promising clean-energy biofuel additives. A kinetics study validated the chemical steps by measuring activation energy values (>60 kJ mol⁻¹). Extending the overall versatility of this catalyst, methanol, ethanol, propanol, pentanol, hexanol and heptanol were utilized in the esterification and yielded remarkable conversion rates to produce levulinates and succinates of C1–C7 alcohols, demonstrating its high potential in industry. In addition, regeneration and scale-up studies were conducted, and industrially and environmentally important metrics, such as Environmental Factor, Process Mass Intensity and Carbon Efficiency, were computed to demonstrate their industrial applicability. This study introduces a functional catalytic material that integrates catalysis, green processing and sustainable technologies, providing an environmentally efficient route to convert renewable feedstocks into next-generation fuel additives.