| abstract |
A highly permeable aromatic polyimide gas separation membrane and the process of using it are disclosed. The aromatic polyimide has the formula ##STR1## wherein --Ar-- is ##STR2## or mixtures thereof, --X, --X 1 , --X 2 and --X 3 independently are alkyl groups having 1 to 6 carbon atoms or aromatic groups having 6 to 13 carbon atoms, and --Z is --H, --X, --X 1 , --X 2 , or --X 3 ; and R is ##STR3## or mixtures thereof. |