PREPARATION OF ANHYDROUS LOWER ALCOHOL

PURPOSE:To prepare an anhydrous lower alcohol efficiently at low cost, by treating a dilute aqueous solution of lowr alcohol in order of a preconcentration process, extraction process, extraction and separation process, and azeotropic distillation process. CONSTITUTION:A dilute aqueous solution of lower alcohol is concentrated into 10-80wt% alcohol concentration by the preconcentation device 1, the prepared concentrated solution is brought into contact with an orgnaic solvent such as an organic acid, alcohol, ketone, etc. by the extractor 2, extracted, separated into an extracted solution and the extraction residue by the separator 3, the extraction residue is returned to the preconcentration device 1, the extracted solution is optionally introduced to the a water reducing device, treated with a dehydrating agent, etc., its water content is reduced, the extracted solution is sent to the azeotropic separator 4, separated by an azeotropic constitution consisting of a low-boiling solvent, water, and a lower alcohol with the low- boiling solvent in the extraction solvent, it is returend to the extractor 2, the azeotropic residue is separated into an anhydrous lower alcohol and the remaining solvent, and the remaining solvent is returned to the extractor 2.