Bio-Solvents: Synthesis, Industrial Production and Applications

Solvents are at the heart of many research and industrial chemical processes and consumer product formulations, yet an overwhelming number are derived from fossils. This is despite societal and legislative push that more products be produced from carbon-neutral resources, so as to reduce our carbon footprint and environmental impact. Biomass is a promising renewable alternative resource for producing bio-solvents, and this review focuses on their extraction and synthesis on a laboratory and large scale. Starch, lignocellulose, plant oils, animal fats and proteins have been combined with creative synthetic pathways, novel technologies and processes to afford known or new bio-derived solvents including acids, alkanes, aromatics, ionic liquids (ILs), furans, esters, ethers, liquid polymers and deep eutectic solvents (DESs)—all with unique physiochemical properties that warrant their use as solvation agents in manufacturing, pharmaceutical, cosmetics, chemicals, energy, food and beverage industries, etc. Selected bio-solvents, conversion technologies and processes operating at commercial and demonstration scale including (1) Solvay’s Augeo™ SL 191 renewable solvent, (2) Circa Group’s Furacell™ technology and process for making levoglucosenone (LGO) to produce dihydrolevoglucosenone (marketed as Cyrene™), (3) Sappi’s Xylex® technology and demonstration scale processes that aim to manufacture precursors for bio-solvents and (4) Anellotech’s Bio-TCat™ technology and process for producing benzene, toluene and xylenes (BTX) are highlighted.