Bio-Based and Eco-Friendly Solvent Systems for Sustainable Industrial and Biological Applications

Abstract

Traditional organic solvents provide considerable environmental and health risks, although their widespread use in chemical manufacturing, pharmaceutical production, and materials processing sectors. This study examines the rational design, systematic assessment, and industrial validation of environmentally benign solvent alternatives, such as deep eutectic solvents, bio-based solvents, and supercritical fluids, aimed at substituting hazardous conventional solvents in extraction, synthesis, and formulation processes. Four case studies investigated the crystallisation of pharmaceutical active ingredients, extraction of natural products, processing of polymers, and treatment of metal surfaces, contrasting green solvents with traditional options in terms of performance, environmental impact, health, safety, and economic factors. Deep eutectic solvents formulated from choline chloride and glycerol attained a 94% yield in pharmaceutical crystallisation, compared to 89% with dichloromethane, while mitigating toxicity and decreasing waste production by 76%. Bio-based ethyl lactate extracted 87-92% of bioactive chemicals from plant materials, in contrast to 91-95% for ethyl acetate, while providing total biodegradability and renewable source. Supercritical carbon dioxide processing of polymers attained comparable product quality to traditional organic solvents, resulting in 65% energy savings and zero emissions of volatile organic compounds. Magnetic deep eutectic solvents achieved metal degreasing with 96% efficiency and total solvent recovery, in contrast to 78% efficiency and 45% losses associated with trichloroethylene. Environmental assessments using solvent selection recommendations indicated a 60-85% enhancement in health and environmental hazard ratings for eco-friendly alternatives. Life cycle study indicated reductions of 35-68% in global warming potential and 42-79% in human toxicity consequences, albeit 15-35% increased material prices in the majority of applications. Industrial pilot experiments validated scalability and process compatibility, demonstrating economic payback times of 1.2 to 3.8 years when factoring in waste treatment savings and regulatory compliance expenses. This study shows that scientifically formulated eco-friendly solvents may equal or surpass the efficacy of traditional solvents while significantly diminishing environmental impact and health hazards, offering viable alternatives for sustainable industrial solvent substitution.