The molecular sieve is a more energy-efficient method than azeotropic distillation. Furthermore, this method avoids the occupational haz­ards associated with azeotropic chemical admixtures. In molecular sieve drying, 95% ethanol is passed through a bed of synthetic zeolite with uniform pore sizes that preferentially adsorb water molecules. Approximately three-fourths of adsorbed material is water and one — fourth is ethanol. The bed becomes saturated after a few minutes and must be regenerated by heating or evacuation to drive out the adsorbed water. During the regeneration phase, a side stream of ethanol/water (often around 50%) is produced, which must be redistilled before return­ing to the drying process [82].