Recycling of Analytical Grade Solvents on a Lab Scale with a Purpose-Built Temperature-Controlled Distillation Unit

Abstract

Solvents constitute a major portion of a chemical laboratory’s waste and cause immediate costs for proper disposal and reordering. Next to reducing solvent usage, the recycling of used solvents by distillation is an obvious measure. In practice, commercially available equipment for distillation often offers insufficient separation and is inappropriately sized, overly costly, or simply not solvent-resistant. We constructed and put into service two distillation units for 6 L batches to recover analytical grade solvents–ethyl acetate and toluene for preparative chromatography and N,N-dimethylacetamide for analytical size exclusion chromatography. The systems separate fractions automatically at freely programmable vapor temperatures with high accuracy (0.1 K). The recovered solvents are therefore highly pure and are reused for analytical applications without any problems. Common laboratory glassware and standard electric components were used for construction. All wetted parts of the distillation systems are s...