Published: August 2003
Solvent usage is an essential part of many industries. Solvents are used in adhesives, paints and coatings, pharmaceuticals, inks and printing, semiconductor manufacturing and metal cleaning. The annual global consumption of solvents is estimated at 30 billion lb/yr (14million t/yr) Consumption in the United States is in excess of 8.4 billion lb/yr (3.8 million t/yr). It comprised almost entirely of solvents. Users of petroleum-based solvents are coming under increasing regulatory pressure to reduce consumption of existing solvents, reduce solvent emissions, recycle spent solvents or replace them with more environmentally friendly substitutes (EFS). One class of solvents vying to replace conventional petroleum-based solvents is bio-based solvents (BBS). The bio-based solvents evaluated in this report, ethyl lactate and methyl soyate are derived from agricultural crops corn and soybeans. In addition to being sourced from both renewable resources, BBS generate less volatile organic compounds (VOCs) than conventional solvents, have lower toxicity and are biodegradable. Increases in production capacity of key raw materials for the production of BBS ethyl lactate and innovations in process technology for both ethyl lactate and methyl soyate have the potential to dramatically reduce BBS production costs. Estimates of the volume of petroleum-based solvents that can be replaced by BBS vary, Argonne National Laboratory estimates that BBS could replace up to 80% of the conventional solvents in use today. In this report, two processes for the production of ethyl lactate (EL) are examined, a lactide route employed by Cargill-Dow (C-D) and a membrane-separation route patented by Argonne National Laboratory (ANL). We also examine the production of the methyl ester of soybean oil methyl soyate (SME) using homogeneous alkaline catalyst. This report should be of interest to manufacturers and consumers of petroleum-based industrial solvents and those interested in the use of bio-based solvents in formulation and cleaning applications.