Compositions of and methods for producing modified monomers and polyimides for sour mixed gas separation

A membrane for separating the components of a sour natural gas feed, the membrane comprising:

• at least three distinct moieties polymerized together, the moieties including a first moiety comprising an alky or acyl group;
• a second moiety selected from the group consisting of:
• 6FDA;
• CARDO;
• 6FpDA;
• TPA;
• mPDA;
• durene diamine;
• PTCDA;
• PMDA;
• BAPT;
• TBB;
• FDA;
• ODA;
• ABL-21;
• 3,3′-dihydroxybenzidine;
• 3,3′-(hexafluoroisopropylidene)dianiline;
• DAM;
• MDEA;
• 9,9-bis(4-aminophenyl-3-isopropyl-5-methylphenyl) fluorene;
• MDA;
• TFMB;
• 4,4′-Diaminooctafluorobiphenyl;
• 4,4′-Diaminobiphenyl;
• 2,3,5,6-Tetrafluoro-1,4-phenylenediamine;
• and BTDA;
• and
• a third moiety selected from the group consisting of:
• 6FDA;
• CARDO;
• 6FpDA;
• TPA;
• mPDA;
• durene diamine;
• PTCDA;
• PMDA;
• BAPT;
• TBB;
• FDA;
• ODA;
• ABL-21;
• 3,3′-dihydroxybenzidine;
• 3,3′-(hexafluoroisopropylidene)dianiline;
• DAM;
• MDEA;
• 9,9-bis(4-aminophenyl-3-isopropyl-5-methylphenyl) fluorene;
• MDA;
• TFMB;
• 4,4′-Diaminooctafluorobiphenyl;
• 4,4′-Diaminobiphenyl;
• 2,3,5,6-Tetrafluoro-1,4-phenylenediamine;
• and BTDA;
• wherein one or more of the first moiety, the second moiety, or the third moiety is generated by carrying out the Friedel-Crafts alkylation or acylation reaction on the polyimide-containing compound to bond an alkyl group or acyl group to a reactive site on an aromatic compound of the polyimide-containing compound.