Recent Advances in the Value Addition of Biomass-Derived Levulinic Acid: A Review Focusing on its Chemical Reactivity Patterns

Abstract

Levulinic acid (LA) is one of the most prominent biomass-derived chemical building blocks that can be transformed into specialty chemicals like fuels, solvents, monomers for polymers, plasticizers, surfactants, agrochemicals, and pharmaceuticals. Over the past three decades, an enormous amount of research data have been acquired on the preparation and downstream value addition of LA, and these works have been reviewed. However, considering the astonishing number of publications appearing every year on LA derivatives, the periodical review of recent works focusing on unique aspects of chemistry must be undertaken to critically evaluate the achievements to date, reassess the challenges, and recognize new opportunities. This review discusses the chemical-catalytic synthesis of various derivatives of LA by focusing on its functionalities and reactivity patterns. Recent literature on some crucial derivatives such as γ-valerolactone, 4,4’-diphenolic acid, and ethyl levulinate have been tabulated and discussed. The synthetic interconversion between various derivatives, mechanistic insights, critical analysis of the reaction parameters toward selective preparation of various derivatives, and their potential commercial applications have been elaborated using predominantly heterogeneous catalysts. A critical assessment of the relative advantages and shortcomings of the existing synthetic strategies for various derivatives of LA has been presented to enkindle fresh ideas. © 2021 Wiley-VCH GmbH