Abstract: Disclosed are a CMS membrane, characterized in that it is obtainable by pyrolysis of a polyimide composed of the monomers 1-(4-aminophenyl)-1,3,3-trimethyl-2H-inden-5-amine and 5-(1,3-dioxo-2-benzofuran-5-carbonyl-2-benzofuran-1,3-dione of the following formulae: preferably by pyrolysis of the polyimide having the CAS number 62929-02-6, and a supported CMS membrane comprising a CMS membrane obtainable from a polyimide by pyrolysis and a porous support, characterized in that a mesoporous intermediate layer is provided between the CMS membrane and the porous support. Further disclosed are a process for preparing the supported membrane, the use of the membranes for separating gas mixtures or liquid mixtures, an apparatus for gas separation or for liquid separation, and the use of the polyimide for preparing a CMS membrane by pyrolysis.

Abstract: Disclosed are a CMS membrane, characterized in that it is obtainable by pyrolysis of a polyimide composed of the monomers 1-(4-aminophenyl)-1,3,3-trimethyl-2H-inden-5-amine and 5-(1,3-dioxo-2-benzofuran-5-carbonyl-2-benzofuran-1,3-dione of the following formulae: preferably by pyrolysis of the polyimide having the CAS number 62929-02-6, and a supported CMS membrane comprising a CMS membrane obtainable from a polyimide by pyrolysis and a porous support, characterized in that a mesoporous intermediate layer is provided between the CMS membrane and the porous support. Further disclosed are a process for preparing the supported membrane, the use of the membranes for separating gas mixtures or liquid mixtures, an apparatus for gas separation or for liquid separation, and the use of the polyimide for preparing a CMS membrane by pyrolysis.