Green environmental assessment and rating for solvents (GEARS) as an innovative tool for solvent selection

Abstract

This study introduces the Green Environmental Assessment and Rating for Solvents (GEARS) as a novel metric designed to evaluate the environmental, functional and economic viability of solvents used in research and industrial applications. GEARS integrates comprehensive Environmental Health and Safety (EHS) criteria with Life Cycle Assessment (LCA) to provide a holistic evaluation of solvent efficiency. The metric assesses ten critical parameters: toxicity, biodegradability, renewability, volatility, thermal stability, flammability, environmental impact, efficiency, recyclability, and cost. Each parameter is scored based on specific thresholds, contributing to an overall score that highlights the strengths and weaknesses of each solvent. The effectiveness of GEARS is demonstrated through case studies evaluating methanol, ethanol, acetonitrile, benzene, and glycerol, revealing insights into their overall performance. The results highlight the importance of using a comprehensive assessment tool to facilitate the selection of greener solvents, thereby promoting sustainable practices in the chemical industry. The GEARS software is available as an open-source tool at bit.ly/GEARS2025. • GEARS is a novel metric for holistic solvent assessment for sustainable applications. • Evaluates 10 parameters: toxicity, cost, renewability, recyclability, and more. • Provides a clear scoring system to guide proper and efficient solvent choices. • Case studies reveal performance differences among common solvents. • Supports sustainable chemistry through data-driven evaluation open-source software.