Abstract: The invention provides a process for continuously preparing polyether alcohols by adding alkylene oxides to H-functional starter substances using a DMC catalyst, comprising the steps of a) preparing a precursor by continuously metering an H-functional starter substance, an alkylene oxide or a mixture of at least two alkylene oxides and the required amount of DMC catalyst into a continuous reactor, b) continuously withdrawing the precursor from step a) from the reactor, c) continuously metering the product from step a), an alkylene oxide different from that in step a) or a mixture of at least two alkylene oxides different from that in step a) and, if appropriate, the required amount of DMC catalyst into a further continuous reactor.

Abstract: The present invention relates to copolymers which are obtainable from the free radical copolymerization of at least (a) a monoethylenically unsaturated carboxylic acid having 3 to 6 carbon atoms or the anhydride thereof with (b) a reaction mixture comprising a component of the general structural formula where R1, R2, R3, R4, independently of one another, are H or C1- to C4-alkyl, n and m, independently of one another, are an integer from 1 to 100 and R5 is H or methyl, a process for the preparation of the polymer according to the invention and the use thereof as a scale inhibitor.

Abstract: The invention provides a process for continuously preparing polyether alcohols using DMC catalysts, which comprises, in a first step, in a continuous reactor, adding alkylene oxides onto H-functional starter substances and transferring the output of this reactor to a second step in a reactor which is divided by closed trays into mutually separate sections, known as compartments, which are connected to one another by external pipelines, in which the output of the reactor from the first step of the reaction passes through the compartments in succession.

Abstract: The invention relates to a process for the continuous preparation of polyether alcohols by reacting H-functional initiators with alkylene oxides using basic catalysts, wherein at least one initiator is metered with at least one alkylene oxide continuously into a back-mixing reactor and the reaction product is removed continuously from the back-mixing reactor.

Abstract: A process for preparing polyether polyols by reaction of the following starting materials: a) one or more alkylene oxides and, if appropriate, carbon dioxide and also b) one or more H-functional starter substances, in the presence of a catalyst, in a reaction unit having a plurality of parallel layers A, B which are microstructured so that each layer has a multiplicity of channels which are arranged parallel to one another and form a continuous flow path from one side of the plate to the opposite side of this, wherein a distribution device for introduction of the starting materials and the catalyst is provided at one end of the channels of the layers A and a collection device for the reaction mixture is provided at the other end of these is proposed.

Abstract: The invention provides a process for preparing polyether alcohols by adding alkylene oxides onto H-functional starter substances using DMC catalysts, which comprises, in a first step, adding propylene oxide or a mixture of propylene oxide and ethylene oxide onto H-functional starter substances and, in a second step, transferring the product thus formed into a tubular reactor in which mixtures of ethylene oxide and propylene oxide are metered in at least two metering points, the proportions of ethylene oxide and propylene oxide in the mixtures metered in in the first and in the second step being different, the proportions of ethylene oxide and propylene oxide in the mixtures metered in at least two metering points in the second step being different, and the mixture metered in in the second step, at least at the last metering point, comprising at least 40% by weight of ethylene oxide.