Copolyimide gas separation membranes derived from substituted phenylene diamines and substituted methylene dianilines

摘要

An aromatic copolyimide gas separation membrane and the process of using it to separate one or more gases from a mixture of gases are disclosed. The aromatic copolyimide is the condensation product of an aromatic tetracarboxylic dianhydride with a phenylene diamine and a methylene dianiline both of which diamines are substituted with alkyl groups on all positions ortho to the amino groups.