TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The aqueous stream containing the organic byproducts of the reaction is fed to the pervaporation unit at 20-100 (preferably 30-70) degrees C. On the feeding side (retentate side) of the pervaporation unit the operating pressure is 0.5-5 (preferably 1-2.5) bar. The permeate side of the pervaporation units the operating pressure is 0.0005-0.5 (preferably 0.001-0.25) bar. The total flow mass is 0.05-10 (preferably 0.1-8) kg/(m2x hour). The method involves feeding aqueous stream from the reaction to a distillation or stripping column; and feeding the aqueous stream enriched in alcohols leaving the head of the column to pervaporation units. Preferred Components: The aqueous stream is enriched in 2-4C alcohols; and has an alcohol concentration of greater than or equal to 40 (preferably greater than or equal to 80, especially greater than or equal to 95) wt.%. The aqueous stream enriched in water has a water concentration of greater than or equal to 95 (preferably greater than or equal to 99) wt.%.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polymeric pervaporation membrane is selected from hydrophilic polymeric membranes, or lipophilic polymeric membranes (preferably hydrophilic polymeric membranes). The hydrophilic polymeric membranes are selected from at least one polymer (p1) selected from polyvinyl alcohol, polyvinyl alcohol/polyacrylic acid copolymers, cellulose diacetate and/or cellulose triacetate. The polymer (p1) is cross-linked; and is selected from polyvinyl alcohol, polyvinyl alcohol/polyacrylic acid copolymers. The lipophilic polymeric membranes are selected from at least one polymer (p2) selected from nitrile rubber, neoprene, polydimethylsiloxane (silicon rubber), polyethylene chlorosulfonate, polysilicone-carbonate copolymers, fluoroelastomers, plasticized polyvinyl chloride, polyurethane, cis-polybutadiene, cis-polyisoprene, polychloroprene , poly(butene-1), ethylene/propylene copolymers, ethylene/propylene/diene terpolymers, polystyrene/butadiene copolymers, styrene/butadiene/styrene block copolymers, styrene/ethylene/butylene block copolymers, thermoplastic polyolefin elastomers, polyesteramides, and/or polyether and polyester block copolymers. The polymer (p2) is cross-linked; and is polyalkylsiloxane. EXAMPLE - No suitable example given.