PURPOSE: To separate water from a water-contg. mixture of toluene and methyl ethyl ketone used for dewaxing of lube oil at a high selectivity and a high flow rate.

CONSTITUTION: A process for separating water from a water-contg. mixture of hydrocarbons and org. oxidized product in which the mixture is brought into contact with a non-porous poly(vinyl pyridine) membrane which has been cross-linked with an aliphat. polyhalide at a higher pressure side, to carry out per-vaporation. Thereby, a transmissible soln. contg. much water from the mixture is obtained to leave a residual soln. contg. much hydrocarbons and the org. oxidized products.