Gas separation composite membrane, gas separation module, gas separation apparatus, gas separation method, and method of producing gas separation composite membrane

1. A gas separation composite membrane, comprising:

a gas permeable supporting layer; and

a gas separating layer containing a crosslinked polyimide resin above the gas permeable supporting layer,

wherein the crosslinked polyimide resin has a structure in which 2 to 4 molecules of a polyimide compound is coordinated with a divalent to tetravalent central metal via an oxygen atom or a sulfur atom,

wherein when the crosslinked polyimide resin has plural central metals, the plural central metals are linked via the polyimide chain of the polyimide compound, and

wherein a concentration of metal complex in a coating liquid forming the gas separating layer is from 0.2% to 30% by mass relative to 100% by mass of the polyimide compound.

2. The gas separation composite membrane according to claim 1 , wherein the polyimide compound has a repeating unit represented by Formula (I), a repeating unit represented by Formula (II-a) or (II-b), and a repeating unit represented by Formula (III-a) or (III-b):

wherein R represents a group having a structure represented by any one of Formulas (I-a) to (I-h); X 1 represents 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 the symbol “*” represents a bonding site to the carbonyl group;

wherein R 3 represents an alkyl group or a halogen atom; R 4 and R 5 each represent an alkyl group or a halogen atom, or are linked to each other to form a ring together with X 2 ; l1, m1 and n1 each represent an integer of from 0 to 4; and X 2 represents a single bond or a divalent linking group; and

wherein R 6 , R 7 , and R 8 each represent a substituent; J 1 represents a single bond or a divalent linking group; l2, m2, and n2 each represent an integer of from 0 to 3; A 1 represents a group selected from the group consisting of —COOH, —OH, —SH, and —S(═O) 2 OH; and X 3 represents a single bond or a divalent linking group.

3. The gas separation composite membrane according to claim 1 , wherein the central metal is Be, Mg, Ca, Sc, Y, Ti, Zr, V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Zn, B, Al, Ga, or In.

4. The gas separation composite membrane according to claim 1 , wherein in a case in which the gas to be separation treated is a mixed gas of carbon dioxide and methane, the permeation rate of the carbon dioxide at 40° C. and 40 atmospheric pressure is more than 20 GPU, and the ratio of the permeation rate of the carbon dioxide to the permeation rate of the methane (R CO2 /R CH4 ) is 15 or more.

5. The gas separation composite membrane according to claim 1 , wherein the supporting layer comprises a porous layer on a side of the gas separating layer and a nonwoven fabric layer on a side reverse thereto.

6. The gas separation composite membrane according to claim 5 , wherein the cut-off molecular weight of the porous layer is 100,000 or less.

7. A gas separation module, comprising the gas separation composite membrane according to claim 1 .

8. A gas separation apparatus, comprising the gas separation module according to claim 7 .

9. A method of separating a gas, comprising causing carbon dioxide to selectively permeate from a gas containing carbon dioxide and methane, using the gas separation composite membrane according to claim 1 .

10. A method of producing a gas separation composite membrane,

wherein the gas separation composite membrane comprises a gas permeable supporting layer, and a gas separating layer above the gas permeable supporting layer,

the method comprising the steps of:

applying a solution comprising a polyimide compound having an active hydrogen-containing group and a metal complex above the gas permeable supporting layer, thereby performing ligand exchange between the polyimide compound and the metal complex; and

forming the gas separating layer comprising a metal-crosslinked polyimide resin above the gas permeable supporting layer,

wherein a concentration of the metal complex in a coating liquid forming the gas separating layer is from 0.2% to 30% by mass relative to 100% by mass of the polyimide compound.

11. The method according to claim 10 , wherein the central atom of the metal complex is Be, Mg, Ca, Sc, Y, Ti, Zr, V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Zn, B, Al, Ga, or In.

12. The method according to claim 10 , wherein the metal complex has two or more ligands selected from the group consisting of an alkoxy group, an aryloxy group, a carboxylate group, a sulfate group, a cyano group, an ammonium group, a phosphate group, a β-diketone, a β-keto ester, and a halogen atom.

13. The method according to claim 10 , wherein the polyimide compound has a repeating unit represented by Formula (I), a repeating unit represented by Formula (II-a) or (II-b), and a repeating unit represented by Formula (III-a) or (III-b):

wherein R represents a group having a structure represented by any one of Formulas (I-a) to (I-h); X 1 represents 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 the symbol “*” represents a bonding site to the carbonyl group;

wherein R 3 represents an alkyl group or a halogen atom; R 4 and R 5 each represent an alkyl group or a halogen atom, or are linked to each other to form a ring together with X 2 ; l1, m1 and n1 each represent an integer of from 0 to 4; and X 2 represents a single bond or a divalent linking group; and

wherein R 6 , R 7 , and R 8 each represent a substituent; J 1 represents a single bond or a divalent linking group; l2, m2, and n2 each represent an integer of from 0 to 3; A 1 represents a group selected from the group consisting of —COOH, —OH, —SH, and —S(═O) 2 OH; and X 3 represents a single bond or a divalent linking group.

14. The method according to claim 10 , wherein the crosslinked polyimide resin has a structure in which 2 to 4 molecules of a polyimide compound is coordinated with a divalent to tetravalent central metal via an oxygen atom or a sulfur atom, and when the crosslinked polyimide resin has plural central metals, the plural central metals are linked via the polyimide chain of the polyimide compound.