GB606608A - Improvements in the manufacture of alcohols by hydration of olefines - Google Patents

Abstract

Ethyl alcohol and isopropyl alcohol are obtained by absorbing ethylene or propylene in sulphuric acid of a concentration not substantially below 85 per cent, hydrolysing the absorption product, separating from the products of hydrolysis any oily or tarry matters, and distilling the residue under sub-atmospheric pressure to obtain a head product of dilute aqueous alcohol and a base product of sulphuric acid of a concentration substantially above 40 per cent. Sulphuric acid of 90 or 95 per cent concentration is preferred for the absorption stage, together with 0.8-1 mols. of ethylene per mol. of sulphuric acid, and 1.2-1.5 mols. of water in the hydrolysis stage. The mixture may be agitated during hydrolysis until the diethyl sulphate phase has disappeared, after which it may be boiled under reflux. The oily or tarry matters separate from the hydrolysis product and may be removed by decantation. The pressure in the distillation step may be about 100 mm., the base temperature should not be above 115 DEG C., and the sulphuric acid remaining may have a concentration of 70 per cent. The last 10-15 per cent of the dilute alcohol recovered is preferably returned to the process by being mixed with the water added to the absorption product. An example is given of a batch and a continuous process.