Abstract: The invention provides an improvement in terms of control and process technology for a method of continuous removal of a component from a liquid mixture using a membrane unit comprising at least one membrane stage. The improvement is that a portion of the overall permeate stream is recycled to the feed vessel and/or beyond the feed vessel but upstream of the conveying device, and the remainder of the overall permeate stream is removed, with the recycled permeate having a higher concentration of the component to be separated off than the removed permeate. The presently disclosed method can especially be used for separation of a homogeneously dissolved catalyst from a liquid reaction mixture.

Abstract: The invention provides a process for preparing an alcohol by hydrogenating an ester which is obtained by alkoxycarbonylating a C2 to C20 hydrocarbon having at least one multiple bond, preferably having at least one olefinic double bond, in which the homogeneous catalyst system used is separated from the product mixture by means of membrane separation. In a development of the present invention, the ester thus formed is converted to another ester by transesterification and then hydrogenated.

Abstract: The present invention provides a process for preparing aldehydes from C2 to C20 olefins using a subsequent membrane separation to separate the homogeneously dissolved catalyst system, wherein prior to the membrane separation a gas exchange that increases the partial pressure fraction of carbon monoxide or hydrogen is carried out in order to boost catalyst retention by the membrane.

Abstract: The invention provides an improvement in terms of control and process technology for a method of continuous removal of a component from a liquid mixture using a membrane unit comprising at least one membrane stage. The improvement is that a portion of the overall permeate stream is recycled to the feed vessel and/or beyond the feed vessel but upstream of the conveying device, and the remainder of the overall permeate stream is removed, with the recycled permeate having a higher concentration of the component to be separated off than the removed permeate. The presently disclosed method can especially be used for separation of a homogeneously dissolved catalyst from a liquid reaction mixture.

Abstract: The invention provides an improvement in terms of control and process technology for a method of continuous removal of a component from a liquid mixture using a membrane unit comprising at least one membrane stage. The improvement is that at least some of the overall permeate stream obtained is recycled to the feed vessel and/or beyond the feed vessel but upstream of the conveying device. The presently disclosed method can especially be used for separation of a homogeneously dissolved catalyst from a liquid reaction mixture.

Abstract: The invention relates to a process for preparing an ester by alkoxycarbonylation of a C2 to C20 hydrocarbon having at least one multiple bond, preferably having at least one olefinic double bond, in which the homogeneous catalyst system used is separated from the product mixture by means of membrane separation and recycled into the reaction zone. In a development of the present invention, the ester thus formed is converted into another ester by transesterification.

Abstract: The present invention provides a process for preparing aldehydes from C2 to C20 olefins using a subsequent membrane separation to separate the homogeneously dissolved catalyst system, wherein prior to the membrane separation a gas exchange that increases the partial pressure fraction of carbon monoxide or hydrogen is carried out in order to boost catalyst retention by the membrane.

Abstract: The invention relates to a process for preparing carboxylic acids or salts thereof by hydrolysis or saponification of an ester, which is obtained by alkoxycarbonylation of a C2 to C20 hydrocarbon having at least one multiple bond, preferably having at least one olefinic double bond, in which the homogeneous catalyst system used is separated from the product mixture by means of membrane separation. In a development of the present invention, the ester thus formed is converted into another ester by transesterification and then hydrolyzed or saponified.

Abstract: The invention relates to a process for preparing an ester by alkoxycarbonylation of a C2 to C20 hydrocarbon having at least one multiple bond, preferably having at least one olefinic double bond, in which the homogeneous catalyst system used is separated from the product mixture by means of membrane separation and recycled into the reaction zone. In a development of the present invention, the ester thus formed is converted into another ester by transesterification.

Abstract: The invention relates to a process for preparing carboxylic acids or salts thereof by hydrolysis or saponification of an ester, which is obtained by alkoxycarbonylation of a C2 to C20 hydrocarbon having at least one multiple bond, preferably having at least one olefinic double bond, in which the homogeneous catalyst system used is separated from the product mixture by means of membrane separation. In a development of the present invention, the ester thus formed is converted into another ester by transesterification and then hydrolyzed or saponified.

Abstract: The invention relates to a process for separating one or more components from a mixture by a membrane separation in which—depending on the component to be separated—an acid or a base is added to the mixture before the membrane separation.

Abstract: The invention provides a process for preparing an alcohol by hydrogenating an ester which is obtained by alkoxycarbonylating a C2 to C20 hydrocarbon having at least one multiple bond, preferably having at least one olefinic double bond, in which the homogeneous catalyst system used is separated from the product mixture by means of membrane separation. In a development of the present invention, the ester thus formed is converted to another ester by transesterification and then hydrogenated.

Abstract: A homogeneous catalyst system is removed from a reaction mixture of two liquid phases by separating the two liquid phases with a membrane having at least one separation-active layer in such a way that the homogeneous catalyst system is at least partially concentrated in a membrane retentate; wherein the reaction mixture contains at least one partially epoxidized cyclic unsaturated compound having twelve carbon atoms; and wherein the membrane separation-active layer contains crosslinked a silicone acrylate and/or polydimethylsiloxane and/or polyimide.

Abstract: An apparatus for the epoxidation of a cyclic unsaturated C12 compound with hydrogen peroxide is provided. The apparatus includes a reactor for carrying out the reaction, wherein the walls of the reactor are at least partially furnished with a separation-active layer of crosslinked silicone acrylates and/or polydimethylsiloxane.

Abstract: The present invention concerns regulating the water content in a process for production of methacrolein. Methacrolein is used in chemical synthesis particularly as an intermediate for production of methacrylic acid, methyl methacrylate or else of active, aroma or flavor chemicals. The present invention is particularly concerned with regulating the water content in a process for production of methacrolein from formaldehyde and propionaldehyde via a Mannich condensation.

Abstract: The present invention concerns regulating the water content in a process for production of methacrolein. Methacrolein is used in chemical synthesis particularly as an intermediate for production of methacrylic acid, methyl methacrylate or else of active, aroma or flavour chemicals. The present invention is particularly concerned with regulating the water content in a process for production of methacrolein from formaldehyde and propionaldehyde via a Mannich condensation.

Abstract: A homogeneous catalyst system is removed from a reaction mixture of two liquid phases by separating the two liquid phases with a membrane having at least one separation-active layer in such a way that the homogeneous catalyst system is at least partially concentrated in a membrane retentate; wherein the reaction mixture contains at least one partially epoxidized cyclic unsaturated compound having twelve carbon atoms; and wherein the membrane separation-active layer contains crosslinked a silicone acrylate and/or polydimethylsiloxane and/or polyimide.