Abstract: The invention relates to a process for the preparation of diaminodicyclohexylmethane (“PACM”) with a proportion of trans,trans-4,4′-diaminodicyclohexylmethane of from 17 to 24% by hydrogenation of diaminodiphenylmethane (“MDA”) in the presence of a pulverulent catalyst in a continuously operated suspension reactor at a conversion of MDA of at least 95%, based on the amount of MDA used.

Abstract: The invention relates to a process for the preparation of diaminodicyclohexylmethane (“PACM”) with a proportion of trans,trans-4,4′-diaminodicyclohexylmethane of from 17 to 24% by hydrogenation of diaminodiphenylmethane (“MDA”) in the presence of a pulverulent catalyst in a continuously operated suspension reactor at a conversion of MDA of at least 95%, based on the amount of MDA used.

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: The invention relates to the use of polyaspartic acids and their mixtures with surfactants and emulsifiers for inhibiting or delaying deposit formation by sparingly soluble organic and inorganic components in the feed of a process that uses a membrane.

Abstract: A process as been found for the removal of water from reaction mixtures of acids or acid anhydrides or of aqueous alkali metal hydroxide solutions with alcohols using vapor permeation/pervaporation at the boiling point of the reaction mixture, which includes initially introducing the lowest-boiling educt in less than the stoichiometric amount, based on the other particular educt, together with this other educt, heating the reaction mixture to the boiling point and freeing the vapor mixture, which is formed from the boiling reaction mixture and includes chiefly water and the lowest-boiling component, from water on a membrane, recycling the vapor mixture which has been freed from water into the reaction mixture and topping up the reaction mixture with the lowest-boiling educt in the course of the reaction.

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.