Gas separation membrane, gas separation module, gas separation apparatus, and polyimide compound
Provided are a polyimide compound including a repeating unit having an aromatic diamine component having a specific structure in which a side-chain benzylic position is regioselectively brominated, a gas separation membrane having a gas separation layer containing the polyimide compound, and a gas separation module and a gas separation apparatus each having the gas separation membrane.
1 . A gas separation membrane comprising a gas separation layer containing a polyimide compound,
wherein the polyimide compound includes a repeating unit represented by formula (I):
in formula (I), R represents a group represented by any one of formulae (I-1) to (I-28), where in formulae (I-1) to (I-28), X 1 to X 3 each represent a single bond or a divalent linking group, L represents —CH═CH— or —CH 2 —, and R 1 and R 2 each represent a hydrogen atom or a substituent, and * represents a bonding site,
in formula (I), L 2 represents a group represented by any one of formulae (II-1) to (II-3):
in formulae (II-1) to (II-3), A represents a group represented by any one of formulae (III-1) to (III-8), B represents unsubstituted methyl, unsubstituted ethyl, unsubstituted n-propyl, unsubstituted i-propyl, a fluorine-substituted alkyl group having 1 to 5 carbon atoms, a fluorine-substituted acyl group having 2 to 6 carbon atoms, or a halogen atom, and * represents a bonding site, wherein at least one A is the group represented by formula (III-4), the group represented by formula (III-5), the group represented by formula (III-6), the group represented by formula (III-7) or the group represented by formula (III-8),
α and β in formula (II-1) are integers satisfying (a), and α1, β1, α2, and β2 in formulae (II-2) and (II-3) are integers satisfying (b),
1≤α≤4,0≤β≤3,2≤α+β≤4 (a)
1≤α1+α2≤8,0≤1+β2≤7,2≤α1+α2+β1+β2≤8 (b)
R a and R b in formula (II-2) each represent a hydrogen atom, unsubstituted methyl, unsubstituted ethyl, unsubstituted n-propyl, unsubstituted i-propyl, or a fluorine-substituted alkyl group having 1 to 5 carbon atoms, and
in formulae (III-1) to (III-8), * represents a bonding site.
2 . The gas separation membrane according to claim 1 , wherein the groups represented by formulae (II-1) to (II-3) each have a fluorine-substituted alkyl group having 1 to 5 carbon atoms.
3 . The gas separation membrane according to claim 1 , wherein the groups represented by formulae (II-1) to (II-3) each have at least one of unsubstituted ethyl, the group represented by formula (III-4), or the group represented by formula (III-5).
4 . The gas separation membrane according to claim 1 , wherein the gas separation membrane is a gas separation composite membrane having the gas separation layer on an upper side of a gas-permeable support layer.
5 . The gas separation membrane according to claim 1 , wherein the gas separation membrane is used for selective permeation of carbon dioxide in a gas including carbon dioxide and methane.
6 . A gas separation module comprising the gas separation membrane according to claim 1 .
7 . A gas separation apparatus comprising the gas separation membrane according to claim 1 .
8 . A polyimide compound comprising a repeating unit represented by formula (I):
in formula (I), R represents a group represented by any one of formulae (I-1) to (I-28), where in formulae (I-1) to (I-28), X 1 to X 3 each represent a single bond or a divalent linking group, L represents —CH═CH— or —CH 2 —, R 1 and R 2 each represent a hydrogen atom or a substituent, and * represents a bonding site,
in formula (I), L 2 represents a group represented by any one of formulae (II-1) to (II-3):
in formulae (II-1) to (II-3), A represents a group represented by any one of formulae (III-1) to (III-8), B represents unsubstituted methyl, unsubstituted ethyl, unsubstituted n-propyl, unsubstituted i-propyl, a fluorine-substituted alkyl group having 1 to 5 carbon atoms, a fluorine-substituted acyl group having 2 to 6 carbon atoms, or a halogen atom, and * represents a bonding site, wherein at least one A is the group represented by formula (III-4), the group represented by formula (III-5), the group represented by formula (III-6), the group represented by formula (III-7) or the group represented by formula (III-8),
α and β in formula (II-1) are integers satisfying (a), and α1, β1, α2, and β2 in formulae (II-2) and (II-3) are integers satisfying (b),
1≤α≤4,0≤β≤3,2≤α+β≤4 (a)
1≤α1+α2≤8,0≤1+β2≤7,2≤α1+α2+β1+β2≤8 (b)
R a and R b in formula (II-2) each represent a hydrogen atom, unsubstituted methyl, unsubstituted ethyl, unsubstituted n-propyl, unsubstituted i-propyl, or a fluorine-substituted alkyl group having 1 to 5 carbon atoms, and
in formulae (III-1) to (III-8), * represents a bonding site.