The present disclosure relates to a hydrogen gas production method including: a first step of generating a mixed gas containing hydrogen and carbon dioxide from a hydrogen storage agent by dehydrogenation reaction using a catalyst in a reactor; a second step of purifying the generated mixed gas to acquire a gas having a high hydrogen concentration; a third step of separating a solution in the reactor into a solution enriched with the catalyst and a permeate using a separation membrane unit; and a fourth step of supplying the solution enriched with the catalyst to the reactor for reusing in the first step.

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.

The present disclosure relates to a method for separating an organic zinc catalyst dispersed in a polyalkylene carbonate resin solution by filtering the polyalkylene carbonate resin solution using a composite filtering membrane, which is a composite material comprising a hydroxyl group-containing material and polyolefin material and has a form in which one or both surfaces of the polyolefin material is coated with the hydroxyl group-containing material.

The invention relates to a process for separating one or more components from a mixture by a membrane separation in whichdepending on the component to be separatedan acid or a base is added to the mixture before the membrane separation.

The invention relates to a process for separating one or more components from a mixture by a membrane separation in whichdepending on the component to be separatedan acid or a base is added to the mixture before the membrane separation.

The invention deals with the separation of homogeneous catalysts from reaction mixtures with the help of organophilic nanofiltration. It is based on the object of indicating an option as to how organophilic nanofiltration can be used economically for separating off homogeneous catalysts from reaction mixtures if the separation-active material of the membrane satisfying the separation aim is not available in sufficiently large amounts or only at high cost. This object is achieved by taking into consideration a particular membrane performance indicator during the design and/or the execution of the corresponding membrane separation process.

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.

An apparatus for the epoxidation of a cyclic unsaturated C.sub.12 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.

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.