Deep Eutectic Solvents for Decarbonization in the Petroleum and Hydrogen Industries: A Critical Review and Roadmap

Abstract Decarbonizing the petroleum and hydrogen industries is essential to climate goals, yet conventional amine scrubbing faces high energy consumption, degradation, and toxicity. This critical review evaluates deep eutectic solvents (DESs) as a next-generation capture platform, offering generally lower toxicity, negligible vapor pressure, and tunable properties; however, these environmental and economic benefits remain uncertain given inconsistent life cycle assessment boundaries and limited pilot-scale data (Sections 8, 10). We bridge molecular design to process-scale engineering, providing a roadmap for implementation. Amine-functionalized DESs achieve CO2 capacities of 0.5–1.35 mol/mol, with life cycle assessments showing 40–60% lower eutrophication and toxicity impacts than MEA. However, high viscosity impedes industrial adoption, keeping DESs at low Technology Readiness Levels (TRL 2–4). Future work should prioritize viscosity reduction (<50 mPa·s), standardized benchmarking, and pilot-scale demonstrations to translate DES technology from a laboratory concept toward industrial decarbonization.