Perspective and prospects of ionic liquids in biodiesel production: a review

Purpose This study aims to provide a comprehensive evaluation of the potential of ionic liquids (ILs) as green alternatives to conventional catalysts and solvents in biodiesel production. It highlights the need for sustainable, low-impact processes that overcome the environmental and energy-intensive limitations of traditional biodiesel synthesis routes. Design/methodology/approach This review systematically examines recent literature on the application of ILs in biodiesel production, focusing on their catalytic mechanisms, extraction efficiency and process optimization. Emphasis is placed on comparing the performance of ILs with that of conventional acid and base catalysts, assessing their reusability, stability and influence on reaction kinetics and yields. Findings It was revealed that ILs exhibit tunable physicochemical properties and impressive solvent versatility, enabling enhanced conversion efficiency and product purity in biodiesel synthesis. They significantly reduce by-product formation and energy consumption while offering potential recyclability. Nonetheless, challenges such as high production cost, toxicity of certain ILs and limited large-scale application remain key barriers to commercialization. Originality/value This review consolidates recent advances in the integration of ILs into biodiesel production and provides a critical perspective on their environmental and economic implications. It offers an updated framework for understanding how IL-based catalytic systems can drive the transition toward more sustainable and circular biofuel production technologies.