Metallgesellschaft Aktiengesellschaft

Metallgesellschaft Aktiengesell-Schaft

Harald Helmrich

Ulrich Heinrich Sander

Peter Hanel

Wilfried Weiss

Erika Schwerdtner

Pavel Soukup

Peter Haenel

Disclosed is a composite membrane for removing water from dilute organic or inorganic acids by pervaporation or vapor permeation. The composite membrane in accordance with the invention is of a porous carrier layer, a porous backing layer, and a non-porous separating layer, which consists of a PVC-PCac copolymer having a PVac content of 10 to 25% by weight of the copolymer.

Composite membrane, process of manufacturing it and process of using it

A multilayer membrane is composed of a carrier layer, a porous supporting layer and a separating layer. The carrier layer consists of fibers of polyamide, polyvinylidene difluoride, polyester or glass; the porous supporting layer consists of a polysulfone, polyvinylidene difluoride, polyethersulfone, polyimide, polyvinyl alcohol, polyurethane, polyacrylonitrile or polyether imide; the separating layer consists of polyvinyl alcohol. The separating layer is nonporous and has a structure having a high microcrystalline content. A process of manufacturing that membrane is also described.

Multilayer membrane and process of manufacturing the same

The process of making a multilayer membrane composed of a carrier layer, a porous supporting layer and a separating layer includes making a modified polyvinyl alcohol by decomposing a polyvinyl ester or ether until the proportion of the vinyl alcohol monomer units in the modified polyvinyl alcohol corresponds to that in a material consisting of 80 to 95% of the polyvinyl ester or ether and 20 to 5% of a polyvinyl alcohol obtained by completely decomposing the polyvinyl ester or ether; preparing a composite material consisting of the carrier layer and the porous supporting layer, preparing a dilute aqueous solution containing 1 to 10% by weight of the modified polyvinyl alcohol; preferably storing the dilute solution at temperatures from -10.degree. to +10.degree. C., preferably from 0.degree. to 5.degree. C., for 3 to 20 days, after storing, applying the dilute solution to the supporting layer of the composite material to coat the composite material with the modified polyvinyl alcohol; and after the applying, heating the composite material coated with the modified polyvinyl alcohol at a temperature of from 100.degree. to 180.degree. for 1 to 60 minutes.

Multilayer membrane and process of manufacturing same

A process is described for the production of alcoholates from alkali metal hydroxides and aliphatic alcohol which in their molecule contain 1 to 6 carbon atoms. The alcoholates are produced in that alkali metal hydroxide is mixed with an alcohol and is reacted with said alcohol at a temperature from 80.degree. to 110.degree. C., preferably from 80.degree. to 100.degree. C., and under a pressure from 0.3 to 1.2 bars, the alcohol water mixture which evaporates during the reaction is separated into its components by at least one membrane, the alcohol vapor and the water vapor are condensed and the condensed alcohol is recycled to the reaction.

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Frankfurt am Main, Germany

Harald Helmrich