THEpreparation of nearly anhydrous alcohol by fractionation of mixtures of aqueous alcohol and benzene, whereby the water is removed as a ternary azeotrope with alcohol and benzene, is well known and widely used on the large scale. A variety of other methods for the dehydration of alcohol have been proposed, such as the use of anhydrous calcium chloride, the use of glycerol alone or in combination with hygroscopic salts, the use of metallic calcium, aluminum, or magnesium, etc. None of these other processes has met with the success of the distillation method in the presence of a liquid which yields an azeotropic mixture owing to the economy of operation which the latter process permits. The distillation process, however, reaches its maximum efficiency only on very large-scale operation, where continuous operation and automatic control can be applied.

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