Polymer and method for producing the same, gas separation membrane, gas separation module, and gas separation apparatus using the polymer, and m-phenylenediamine compound

A gas separation membrane comprising, as a polymer for a gas separation layer, a polyimide compound having a constitutional unit represented by formula (II) below,

• wherein in the formula (II), RA, RB, and RC represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom,
• at least one of RA, RB, or RC represents an alkyl group having 1 to 4 carbon atoms,
• the alkyl group having 1 to 4 carbon atoms is not trifluoromethyl, and
• R represents a group represented by any one of formulae (I-1) to (I-28) below, where X1 to X3 represent a single bond or a divalent linking group, L represents —CH═CH— or —CH2—, R1 and R2 represent a hydrogen atom or a substituent, and * represents bonding sites with carbonyl groups in the formula (II).

A m-phenylenediamine compound represented by formula (Ia-1) below,

• wherein in the formula (Ia-1), Ra represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a halogen atom, a hydroxy group, an alkoxy group having 1 to 3 carbon atoms, or an acyloxy group having 1 to 3 carbon atoms,
• —C(Ra)3 has 1 to 4 carbon atoms and is not trifluoromethyl,
• RB and RC represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom,
• the alkyl group that is represented by RB and RC and has 1 to 4 carbon atoms is not trifluoromethyl, and
• RB, RC and all Ras do not represent a hydrogen atom simultaneously.