Kraft Lignin Ethanolysis over Zeolites with Different Acidity and Pore Structures for Aromatics Production

To utilize its rich aromatics, lignin, a high-volume waste and environmental hazard, was depolymerized in supercritical ethanol over various zeolites types with different acidity pore structures. Targeting at high yield/selectivity of aromatics such as phenols, microporous Beta, Y, ZSM-5 were first examined lignin ethanolysis, followed by similar micropore size but acidity. Further comparisons made between fin-like worm-like mesoporous structures their counterparts. Despite depolymerization complexity diversified ethanolysis products, strong found effective to cleave both C–O–C C–C linkages while mild works mainly ether bond breakdown. However, when diffusion gigantic molecules is severe, size, particularly mesopores, becomes more decisive on phenol selectivity. These findings provide important guidelines future selection design appropriate structure promote or other hydrocarbon cracking processes.