The use of alternative solvent purification techniques

Abstract

A recent accident at the University of California, Irvine involved the purification of an organic solvent using a solvent still resulting in a fire in the lab. A graduate student was seriously burned and $3.5 million in property damage was incurred. In this report, lessons learned from this accident are used to improve the safety of solvent purification operations. Column methods of aprotic solvent purification processes, as well, as the purchasing of ultra-dry organic synthesis solvents are evaluated. Residual risks associated with the solvent still operation are compared with the alternative purification methods. While severity remains unchanged using the column method, employing the column reduces the likelihood of an accident. For most applications, the column method and the purchase of ultra-dry solvents remove moisture and oxygen at least to the same level as the solvent still method. This is not without additional costs. Column system have higher upfront capital costs and ultra-dry solvents cost 20-50% more than certified solvents. Cost-benefit analysis argues that the additional costs make alternative purification methods acceptable. In conclusion, column methods of aprotic solvent purification processes and the purchasing of ultra-dry organic synthesis solvents are, in many applications, a cost-effective alternative to solvent stills for producing a moisture- and oxygen-free product.