Abstract: A method of cleaning surfaces made of glass, graphite, ceramics, polymeric and metallic materials, synthetic and vegetable fibres, e.g. fabrics, textiles or waste paper, in particular membrane surfaces, by detaching or dissolving organic and inorganic soilings by a simple flushing operation, where a solution of an iminocarboxylic acid, a polyamino acid, an emulsifier or a mixture thereof is used.

Abstract: A process has been found for the preparation of dialkyl maleates from maleic acid, maleic anhydride or monoalkyl maleates with C.sub.1 -C.sub.8 -alcohols, in particular ethanol, in the presence or absence of an acidic catalyst and at boiling heat, which is characterized in that the escaping water/alcohol/vapour mixture, together with its condensed phase if appropriate, is conducted as feed along a hydrophilic membrane at which it is purged of water and the dehydrated alcohol is returned to the reaction mixture.

Abstract: A first alkanol having from 1 to 3 carbon atoms can be separated off from other organic compounds of higher carbon number from the group comprising other alcohols, polyalcohols, ethers, oxo compounds, esters of carboxylic acids and of carbonic acid, haloaliphatics, amines, amides, hydrocarbons, carboxylic acids and nitriles, which in each case have at least 1 carbon atom more than the first alkanol, where in the case of halogenoaliphatics, halogen substituents are counted as further carbon atoms, by permeation on membranes, if a water content from 1 to 30% by weight, preferably from 5 to 15% by weight, based on the amount of mixture and water, is maintained.

Abstract: Methanol can be substantially removed from dimethyl carbonate (DMC)/methanol mixtures by absorption on ion exchange resins. The enriched DMC is obtained as filtrate. The absorption is carried out at from -50.degree. C. to +100.degree. C. and 0.1-10 bar.

Abstract: A first alkanol having 1 to 3 C atoms or a mixture of this first alkanol with water or water itself can be separated off from oxygen-containing organic compounds having 3 to 7 C atoms from the group comprising second alkanols and dialkyl carbonates, which always have at least 2 C atoms more than the first alkanol, by permeation on membranes if a membrane obtained by plasma polymerization is employed.