Desiccant efficiency in solvent and reagent drying 8. molecular sieve column drying of 95% ethanol: An application of hygrometry to the assay of solvent water content

Abstract

The use of hygrometry for the measurement of ethanol water content and the application of molecular sieves for column drying of 95% ethanol are described. The commercial hygrometer used in this study permitted measurement of water content in the range 0.005-5% (by vol) but was subject to a number of limitations which made measurements more time-consuming than anticipated. Grossly wet ethanol containing 5% (by vol) water was readily dried to a water content of about 0.3% (by vol), by treatment with a column of 3A molecular sieves. Slow flow rates enhanced the drying action, which was largely independent of the column dimensions and scale of the drying process. Water breakthrough occurred when water adsorption by the sieves exceeds about 10% (by wt).