JP6547503B2 - Gas separation membrane - Google Patents

Description

  The present invention relates to a gas separation membrane. In particular, it relates to a separation membrane of carbon dioxide.

  In recent years, there has been an increasing demand for a technology for efficiently and economically separating and recovering carbon dioxide from other gases (hereinafter sometimes referred to as "gas").

  For example, in order to extract natural gas and use methane gas obtained from biomass as fuel, it is necessary to separate carbon dioxide from these gases and to concentrate the methane gas. In addition, as measures against global warming, it has been studied to separate and collect carbon dioxide emitted by combustion of fossil fuel and store it in the ground (Non-Patent Document 1).

  As a technology for separating and recovering carbon dioxide, there are a chemical adsorption method, a physical adsorption method, a separation method using an adsorbent, and the like. Above all, membrane separation is attracting attention as a technology that can realize low environmental load and low cost.

  In the membrane separation method, “solubility of gas molecules on the membrane surface” and “aggregation in the membrane” occur when gas permeates through the polymer membrane by utilizing the pressure difference between the gases separating the membranes. This is a technology for separating two or more types of mixed gases by the difference in the “diffusivity of gas molecules in the interstices of polymer chains”, and the polymer membrane used for gas separation is a gas separation membrane.

  As materials for gas separation membranes, polymer materials such as cellulose acetate, polysulfone and polyimide are known. However, since the gas separation membrane using the above-mentioned polymer material has low gas permeability, the membrane separation method has not reached widespread use as a separation and recovery technology of carbon dioxide, and the separation efficiency is excellent with excellent gas permeability. Researches for creating polymer materials are actively conducted.

  For example, as a method of improving gas permeability, it has been revealed that it is effective to introduce a fluorine atom into the chemical structure of a polymer material. Non-Patent Document 2 describes that by introducing a fluorine atom into polyimide, the free volume fraction indicating the proportion of the passage of gas is increased, and the gas permeability is improved.

  On the other hand, in Non-Patent Document 3, basic nitrogen such as amine has high affinity to carbon dioxide, and the permeability and selectivity of carbon dioxide are improved by introducing a basic nitrogen functional group into the polymer. It is described. Non-Patent Document 4 compares the gas permeability of a polypyridine ester having a basic nitrogen atom and a polypyridine ester in which the basic nitrogen is protected by a methyl group to eliminate the effect of the basic atom, It is described that the polypyridine ester having the carbon dioxide is more excellent in carbon dioxide permeability and selectivity.

Although gas separation membranes containing both fluorine atoms and basic nitrogen atoms are extremely rare, Patent Documents 1, 2 and 3 disclose gas separation membranes using polymer compounds containing both atoms. Is described. The polymer compound is a copolymer comprising a polyimide skeleton having a hexafluoroisopropanol group (—C (CF ₃ ) ₂ OH, hereinafter abbreviated as HFIP group) and a fluorine-containing heterocyclic skeleton having a basic nitrogen atom. is there.

  In the future, if gas separation membranes are widely used in industrial applications as carbon dioxide separation and recovery techniques, gas separation membranes with superior carbon dioxide permeability and excellent selectivity, which are superior in efficiency and economy to other separation techniques, can be used. Is considered necessary.

JP, 2013-010096, A JP, 2014-128787, A JP 2014-128788 A

Toray Research Center Research and Research Department issued 'Gas Gas and Gas Separation Technology Co., Ltd.' pp 307, 2011 S. A. Stern, Journal of Membrane Science, Vol, 94, 1-65, 1994 Published by Toray Research Center Research and Development Department, 'Gas Barrier and Gas Separation Technology Co., Ltd.' pp 312-314, 2011 H. R. Kricheldorf, P .; Jahnke, N .; Scharnagl, Macrolecules, vol. 25, pp 1382-1386, 1992

  An object of the present invention is to provide a gas separation membrane which has a high gas permeation coefficient and is excellent in gas throughput per unit time in separation operation. In particular, it is an object of the present invention to provide a gas separation membrane having a high permeability coefficient of carbon dioxide.

  As a result of intensive investigations, the present inventors thought of a gas separation membrane containing a polymer compound having a repeating unit represented by the general formula (1). The gas separation membrane substantially having no protic acidic group such as an HFIP group improves the gas permeability, and in particular, the permeability coefficient of carbon dioxide is high, and the problem has been solved.

(Wherein, R ¹ is a single bond or a methylene chain, R ² is a hydrogen atom or a methyl group, and R ³ is a divalent organic group).
Specifically, the gas separation membrane of the present invention has the following general formula (1A)

(Wherein, R ¹ is a single bond or a methylene chain, R ² is a hydrogen atom or a methyl group, and R ³ is a divalent organic group)
A precursor consisting of a polyamide containing a repeating unit represented by (hereinafter sometimes referred to as precursor polyamide (1A)) is prepared by polymerization,
The precursor polyamide (1A) is then cyclized by heating,
General formula (1):

A polymer compound having a repeating unit represented by (hereinafter, may be referred to as a polymer compound (1)) is used.

  In the case where both a basic nitrogen atom and a structure of an acidic HFIP group are present in the structure of the polymer compound as in the precursor polyamide (1A), the present inventors are a protic acid group. The acidic hydrogen atom at the hydroxy site in the HFIP group interacts with the basic nitrogen atom to lose the basicity of the nitrogen atom, so that the affinity of the nitrogen atom for carbon dioxide is not fully utilized and the high permeation of carbon dioxide It was guessed that it was difficult to obtain

  The present inventors cyclized the HFIP group in the precursor polyamide (1A) to remove the hydroxy group of the HFIP group, and the polymer compound (1) has a basic nitrogen atom and a tricycle in the heterocyclic structure. The gas permeability is significantly improved by the respective effects of the fluoromethyl group being expressed, and when separating carbon dioxide from a mixed gas, it functions as a gas separation membrane excellent in the amount of processed gas per unit time. I found it.

The present invention includes the following inventions 1 to 13.
[Invention 1]
General formula (1):

Wherein R ¹ is a single bond or a methylene chain, R ² is a hydrogen atom or a methyl group, and R ³ is a divalent organic group. A polymer compound having a repeating unit represented by Including
In addition, in the polymer compound, the number of hexafluoroisopropanol groups is 20% or less of the total number of the following fluorine-containing heterocyclic structure (A):

Gas separation membrane.
[Invention 2]
The polymer compound having a repeating unit represented by the general formula (1) is a polymer compound in which the content of the repeating unit represented by the general formula (1) with respect to the polymer compound is 90% by mass or more. The gas separation membrane of the invention 1.
[Invention 3]
The gas separation membrane of the invention 1 whose polymer compound which has a repeating unit represented by General formula (1) is a polymer compound which consists only of repeating units represented by General formula (1).
[Invention 4]
In the above general formula (1), R ¹ is a methylene chain, R ² is a hydrogen atom, and a divalent organic group R ³ is
Formula (2):

The gas separation membrane of the invention 1-3 which is group represented by these.
[Invention 5]
In the above general formula (1), R ¹ is a methylene chain, R ² is a hydrogen atom, and a divalent organic group R ³ is
Formula (3):

The gas separation membrane of the invention 1-3 which is group represented by these.
[Invention 6]
In the above general formula (1), R ¹ is a methylene chain, R ² is a hydrogen atom, and a divalent organic group R ³ is
Formula (4):

The gas separation membrane of the invention 1-3 which is group represented by these.
[Invention 7]
In the above general formula (1), R ¹ is a methylene chain, R ² is a hydrogen atom, and a divalent organic group R ³ is
Formula (5):

The gas separation membrane of the invention 1-3 which is group represented by these.
[Invention 8]
In the above general formula (1), R ¹ is a single bond, R ² is a methyl group, and a divalent organic group R ³
But,
Formula (2):

The gas separation membrane of the invention 1-3 which is group represented by these.
[Invention 9]
In the above general formula (1), R ¹ is a single bond, R ² is a methyl group, and a divalent organic group R ³ is
Formula (3):

The gas separation membrane of the invention 1-3 which is group represented by these.
[Invention 10]
In the above general formula (1), R ¹ is a single bond, R ² is a methyl group, and a divalent organic group R ³ is
Formula (4):

The gas separation membrane of the invention 1-3 which is group represented by these.
[Invention 11]
In the above general formula (1), R ¹ is a single bond, R ² is a methyl group, and a divalent organic group R ³ is
Formula (4):

The gas separation membrane of the invention 1-3 which is group represented by these.
[Invention 12]
A gas separation method, wherein carbon dioxide is separated from a gas containing at least carbon dioxide using the gas separation membrane according to any of the first to eleventh aspects.
[Invention 13]
The gas separation method of invention 12, wherein carbon dioxide is separated from a gas containing at least hydrocarbon and carbon dioxide.

  The gas separation membrane of the present invention is superior in gas permeability to the conventional gas separation membrane while having the carbon dioxide selectivity equivalent to that of the conventional gas separation membrane. In particular, there is an effect that the gas throughput per unit time is high in the separation operation of carbon dioxide from the mixed gas containing carbon dioxide.

General formula (1) which the gas separation membrane of the present invention comprises

(Wherein, R ¹ is a single bond or a methylene chain, R ² is a hydrogen atom or a methyl group, and R ³ is a divalent organic group)
A fluorine-containing heterocyclic structure (A) contained in the repeating unit represented by

When there is present in the polymer compound, the base having excellent affinity for carbon dioxide and the trifluoromethyl group which has the effect of improving the gas diffusivity by increasing the proportion of the free volume which becomes the passage of the gas. Together with the reactive nitrogen atoms. In this case, unlike the presence of the HFIP group which is a protic acid group as in the precursor polyimide (1A), the nitrogen atom in the heterocyclic structure does not lose basicity, so the gas separation membrane of the present invention Permeability to carbon dioxide was estimated to be excellent.

  The polymer compound having a repeating unit represented by the general formula (1) used in the gas separation membrane of the present invention is a precursor polyamide having an HFIP group by polymerizing a diamine having an HFIP group and a dicarboxylic acid derivative as a raw material compound. The solution is prepared into a solution containing the compound and then heated to form a fluorine-containing heterocyclic structure.

  In the polymer compound contained in the gas separation membrane of the present invention, the number of HFIP groups which are protic acid groups is 20% or less of the total number of fluorine-containing heterocyclic structures (A) contained in the polymer compound, It is preferably at most 10%, particularly preferably at most 5%, and most preferably one containing no HFIP group. However, in the synthesis of the polymer compound having the repeating unit represented by the general formula (1) contained in the gas separation membrane of the present invention, the precursor polyamide (1A) is cyclized by heating and the general formula having no HFIP group In the cyclization reaction for obtaining the polymer compound having a repeating unit represented by (1), a partially uncyclized structure may remain.

In addition to the HFIP group, examples of the above-mentioned protic acid group may include phenol group and carboxyl group.
1. Diamine having an HFIP group The diamine having an HFIP group, which is a monomer compound used when synthesizing the polymer compound (fluorine-containing heterocyclic polymer compound) used for the gas separation membrane of the present invention, has the following general formula ( It is represented by 1B).

In the formula, R ¹ is a single bond or a methylene chain, and R ² is a hydrogen atom or a methyl group.

  As a diamine represented by General formula (1B), the diamine represented by the following formula (5) and Formula (6) can be illustrated, for example. Hereinafter, the diamine represented by Formula (5) may be called HFIP-MDA, and the diamine represented by Formula (6) may be called HFIP-mTB. HFIP-MDA and HFIP-mTB may be used alone or in combination.

2. Dicarboxylic Acid Derivative A dicarboxylic acid derivative as a raw material compound for synthesizing the polymer compound (fluorine-containing heterocyclic polymer compound) represented by the general formula (1) used for the gas separation membrane of the present invention is represented by the following general formula ( 7) and the general formula (8).
[Dicarboxylic Acid Derivative Represented by General Formula (7)]

In the formula, R ³ is a divalent organic group. Preferably, it is an aliphatic hydrocarbon group, a divalent organic group having an alicyclic or aromatic ring, may contain a nitrogen atom, an oxygen atom or a sulfur atom in the structure, and part of hydrogen atoms is a fluorine atom, chlorine It may be substituted by an atom, a bromine atom, an iodine atom, an alkyl group, a fluoroalkyl group or a cyano group. A is each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
[Dicarboxylic Acid Derivative Represented by General Formula (8)]

In the formula, R ⁴ is a divalent organic group. Preferably, it is an aliphatic hydrocarbon group, a divalent organic group having an alicyclic or aromatic ring, may contain a nitrogen atom, an oxygen atom or a sulfur atom in the structure, and part of hydrogen atoms is a fluorine atom, chlorine It may be substituted by an atom, a bromine atom, an iodine atom, an alkyl group, a fluoroalkyl group or a cyano group. X is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

  In order to synthesize a polymer compound (fluorine-containing heterocyclic polymer compound) containing a repeating unit represented by the general formula (1) used in the gas separation membrane of the present invention, it can be represented by the general formula (7) or the general formula (8) The dicarboxylic acid derivatives represented can be used.

  If these dicarboxylic acid derivatives are specifically described with dicarboxylic acids as raw materials, oxalic acid as aliphatic dicarboxylic acid, malonic acid, succinic acid, glutaric acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid or sebacic acid, aroma Acid, isophthalic acid, terephthalic acid, 3,3'-dicarboxylic diphenyl ether, 3,4-dicarboxyl diphenyl ether, 4,4'-dicarboxylic diphenyl ether, 3,3'-dicarboxylic diphenylmethane, 3 4, 4-dicarboxyldiphenylmethane, 4,4'-dicarboxyldiphenylmethane, 3,3'-dicarboxyldiphenyldifluoromethane, 3,4-dicarboxyldiphenyldifluoromethane, 4,4'-dicarboxyldiphenyldifluoromethane, 3, 3 ' Dicarboxyl diphenyl sulfone, 3,4-dicarboxyl diphenyl sulfone, 4,4'-dicarboxyl diphenyl sulfone, 3,3'-dicarboxyl diphenyl sulfide, 3,4-dicarboxyl diphenyl sulfide, 4,4'-di Carboxyl diphenyl sulfide, 3,3'-dicarboxyl diphenyl ketone, 3,4-dicarboxyl diphenyl ketone, 4,4'-dicarboxyl diphenyl ketone, 3,3'-dicarboxyl diphenylmethane, 3,4-dicarboxyl diphenylmethane, 4,4'-Dicarboxyldiphenylmethane, 2,2-bis (3-carboxyphenyl) propane, 2,2-bis (3,4'-carboxyphenyl) propane, 2,2-bis (4-carboxyphenyl) propane , 2, 2-bis (3- Voxyphenyl) hexafluoropropane, 2,2-bis (3,4'-carboxyphenyl) hexafluoropropane, 2,2-bis (4-carboxyphenyl) hexafluoropropane, 1,3-bis (3-carboxyphenoxy) Benzene, 1,4-bis (3-carboxyphenoxy) benzene, 1,4-bis (4-carboxyphenoxy) benzene, 3,3 ′-(1,4-phenylenebis (1-methylethylidene)) bisbenzoic acid 3,4 ′-(1,4-phenylenebis (1-methylethylidene)) bisbenzoic acid, 4,4 ′-(1,4-phenylenebis (1-methylethylidene)) bisbenzoic acid, 2,2 -Bis (4- (3-carboxyphenoxy) phenyl) propane and 2,2-bis (4- (4-carboxyphenoxy) phenyl) prop 2,2-bis (4- (3-carboxyphenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (4-carboxyphenoxy) phenyl) hexafluoropropane, 2,2-bis (4- ( 3-Carboxyphenoxy) phenyl) sulfide, 2,2-bis (4- (4-carboxyphenoxy) phenyl) sulfide, 2,2-bis (4- (3-carboxyphenoxy) phenyl) sulfone or 2,2-bis (4- (4-Carboxyphenoxy) phenyl) sulfone, 4- (perfluorononenyloxy) phthalic acid as a perfluorononenyloxy group-containing dicarboxylic acid, 5- (perfluorononenyloxy) isophthalic acid, 2- (perfluorononenyloxy) isophthalic acid (Perfluorononenyloxy) terephthalic acid or 4-methoxy-5- (perfluoronone) Nyloxy) isophthalic acid, 4- (perfluorohexenyloxy) phthalic acid as a perfluorohexenyloxy group-containing dicarboxylic acid, 5- (perfluorohexenyloxy) isophthalic acid, 2- (perfluorohexenyloxy) terephthalic acid or 4- (perfluorohexenyloxy) terephthalic acid Methoxy-5- (perfluorohexenyloxy) isophthalic acid can be exemplified. These dicarboxylic acid derivatives may be used alone or in combination of two or more.

Acid dichlorides are preferred in view of reactivity with diamines, and isophthalic acid dichloride, tephthalic acid chloride, 4,4'-biphenyl carbonyl chloride and 4,4'-dicarboxyl diphenyl ether are particularly preferred in view of easy availability.
3. Synthesis of Polyamide Precursor The polymer compound (fluorine-containing heterocyclic polymer compound) having a repeating unit represented by the general formula (1) used for the gas separation membrane of the present invention is an HFIP represented by the above-mentioned formula (1B) It can synthesize | combine by dehydrating-cyclizing the precursor polyamide obtained by condensation-polymerizing the diamine which has group and the dicarboxylic acid derivative represented by General formula (7), (8). For example, a precursor polyamide obtained by condensation polymerization of a diamine having an HFIP group represented by the above formulas (5) and (6) and a dicarboxylic acid derivative represented by the general formulas (7) and (8) It can be synthesized by dehydration cyclization.

  The polymer compound of the present invention is high in order to improve the organic solvent solubility, moldability, strength when used as a gas separation membrane, weather resistance, corrosion resistance, etc. when producing a gas separation membrane. The total amount of molecular compounds may contain a repeating unit not belonging to the general formula (1), but from the viewpoint of increasing the gas permeation amount per unit time, the inclusion of the repeating unit represented by the general formula (1) It is preferable that the ratio be 90% by mass or more.

  In order to introduce a repeating unit not belonging to the general formula (1) into the polymer compound contained in the gas separation membrane of the present invention, a diamine compound not belonging to the general formula (1B) (hereinafter referred to as another diamine compound) There may be used in combination, which is one of the preferred embodiments of the present invention. The amount used is less than 10% by mass with respect to the total amount of the diamine compound used. If the proportion of the other diamine compound is 10% by mass or more, a significant decrease in carbon dioxide permeability or selectivity may occur. The polymer compound substantially consisting only of the repeating unit represented by the general formula (1) can preferably perform the separation of carbon dioxide, so other diamines should not be used unless necessary. Is also possible. As another diamine compound, what does not contain a protic acidic group is preferable.

  Specific examples of other diamine compounds that can be used in combination include 5- (trifluoromethyl) -1,3-phenylenediamine, 2- (trifluoromethyl) -1,3-phenylenediamine, 4- (trifluoromethyl) 1,3-phenylenediamine, 2- (trifluoromethyl) -1,4-phenylenediamine, 2,2'-bis (trifluoromethyl) benzidine, 2,2'-difluoro-4,4'-diaminodiphenyl 2,2'-Dichloro-4,4'-diaminodiphenyl, 2,2'-dibromo-4,4'-diaminodiphenyl, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-dimethyl 1,3-phenylenediamine, 2,5-dimethyl-1,3-phenylenediamine, 2,3-dimethyl-1,4-phenylenediamine, 2,5-dimer Chill-1,4-phenylenediamine, 2,6-dimethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 2,2'-dimethylbiphenyl-4, 4'-diamine, 2,2'-dimethoxy-4,4'-diaminodiphenyl, 2,2'-diethoxy-4,4'-diaminodiphenyl, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether 4,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis ( 4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, bis (4- (3-aminophenoxy) phenyl) sulfone, Bis (4- (4-aminophenoxy) phenyl) sulfone, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoro Propane, 2,2-bis (4- (3-aminophenoxy) phenyl) propane, 2,2-bis (4- (3-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (4 (4 -Aminophenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis (3-amino-4-) Hydroxyphenyl) hexafluoropropane, 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, or 4,4 ′ It can be exemplified diamino benzanilide. The other diamine compounds may be used alone or in combination of two or more.

  Preferably, 5- (trifluoromethyl) -1,3-phenylenediamine, 2- (trifluoromethyl) -1,3-phenylenediamine, 4- (trifluoro), which is a fluorine-containing compound which can be expected to have high gas permeability. Methyl) -1,3-phenylenediamine, 2- (trifluoromethyl) -1,4-phenylenediamine, 2,2'-bis (trifluoromethyl) benzidine or 2,2-bis (4- (4-amino) Phenyl) hexafluoropropane.

  The polymerization reaction in synthesizing the precursor polyamide will be described. The precursor polyamide used for the gas separation membrane according to the present invention essentially comprises a diamine having a HFIP group and a dicarboxylic acid derivative, and the aromatic compound in an organic solvent or at no solvent at a temperature of −100 ° C. or more and 100 ° C. or less It can synthesize | combine by mixing and carrying out the condensation reaction of diamine and a dicarboxylic acid derivative.

  In the present polymerization reaction, it is desirable that the diamine and the dicarboxylic acid derivative be expressed in a molar ratio and be reacted 1: 1 in an inert gas such as nitrogen or argon. If the reaction temperature is lower than -100 ° C, the reaction does not proceed, and if the reaction temperature is higher than 100 ° C, the dicarboxylic acid derivative may partially react with the hydroxy moiety of the HFIP group of the diamine derivative. Preferably, the temperature is −90 ° C. or more and 0 ° C. or less, and after mixing the aromatic diamine and the dicarboxylic acid derivative, the temperature is preferably gradually raised.

  The organic solvent that can be used for the polymerization reaction can be used without particular limitation as long as the diamine having the HFIP group and the dicarboxylic acid derivative, which are raw material compounds, dissolves, and amide solvents, ether solvents, aromatic solvents, halogen System solvents or lactone solvents can be used. Specifically, as an amide solvent, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylformamide, hexamethylphosphoric acid triamide or N-methyl-2-pyrrolidone, and as an ether solvent, Diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, diphenyl ether, dimethoxyethane, diethoxyethane, tetrahydrofuran, dioxane or trioxane, and aromatic solvents such as benzene, anisole, nitrobenzene or benzonitrile, halogen type As a solvent, chloroform, dichloromethane, 1,2-dichloroethane or 1,1,2,2-tetrachloroethane, as a lactone solvent, γ-butyrolactone, γ-bar Examples include lelolactone, ε-valerolactone, ε-valerolactone, γ-caprolactone, ε-caprolactone, or α-methyl-γ-butyrolactone.

Preferably, N, N-dimethylformamide, N, N-dimethylacetamide or N-methyl-2-pyrrolidone having high solubility of the aromatic diamine and the dicarboxylic acid derivative as raw materials are used.
4. Preparation of Polyamide Precursor Solution The precursor polyamide solution obtained by the above synthesis method can be used as it is for the production of a gas separation membrane. In addition, after the precursor polyamide solution is added to a poor solvent such as water or alcohol for the purpose of removing residual monomers and low molecular weight substances contained in the precursor polyamide solution, the precursor polyamide is precipitated and isolated and purified. Alternatively, it may be prepared by dissolving it in an organic solvent.

As the organic solvent which can be used, an amide solvent, an ether solvent, an aromatic solvent, a halogen solvent or a lactone solvent can be used as long as the precursor polyamide is dissolved. Specifically, as an amide solvent, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylformamide, hexamethylphosphoric acid triamide or N-methyl-2-pyrrolidone, and as an ether solvent, Diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, diphenyl ether, dimethoxyethane, diethoxyethane, tetrahydrofuran, dioxane, or trioxane, and as an aromatic solvent, benzene, anisole, nitrobenzene or benzonitrile, As a halogen-based solvent, chloroform, dichloromethane, 1,2-dichloroethane or 1,1,2,2-tetrachloroethane, as a lactone-based solvent, γ-butyrolactone .gamma.-valerolactone, .epsilon.-valerolactone, .epsilon.-valerolactone, .gamma.-caprolactone, it can show an example .epsilon.-caprolactone, or α- methyl -γ- butyrolactone. From these solvents, they may be selected and used, or two or more types of mixed solvents may be used.
5. Method for Producing Gas Separation Membrane The gas separation membrane containing the polymer compound according to the inventions 1 to 13 of the present invention is molded with a precursor polyamide solution, then the solvent is evaporated, and the carbonyl group (-C in the precursor polyamide) It can manufacture by cyclodehydration reaction of (= O)-) and the hydroxyl group (-OH) in HFIP group. The gas separation membrane may be either an entirely uniform membrane structure or an asymmetric membrane having a dense layer and a porous layer.

  The gas separation membrane having a totally homogeneous structure may be prepared, for example, by wet-coating the above-described precursor polyamide solution onto a substrate such as a glass substrate using a spin coater or an applicator or the like, and then drying such as air, nitrogen or argon. After heating in a gas, evaporation of the solvent, and the cyclization dehydration reaction, it is obtained by peeling from the glass substrate. For use as a gas separation membrane, the film thickness is preferably 5 μm or more and 1 mm or less. If the thickness is less than 5 μm, film formation is difficult and the film is easily broken. If the thickness is more than 1 mm, gas may not be easily transmitted. More preferably, they are 10 micrometers or more and 100 micrometers or less.

  The heating temperature at which the cyclization reaction proceeds is preferably 100 ° C. or more and 400 ° C. or less, and more preferably 150 ° C. or more and 350 ° C. or less. When the heating temperature is lower than 100 ° C., the drying removal of the solvent and the cyclization dehydration reaction can not be sufficiently performed, and when the heating temperature is higher than 400 ° C., film defects such as film breakage occur.

  As a method of forming a gas separation membrane as an asymmetric structural membrane having a dense layer and a porous layer, a precursor polyamide solution is put in a pressure vessel, and it is compatible with the solvent of the precursor polyamide solution from the discharge port. The precursor polyamide is discharged into a bath filled with a coagulating solution using a poor solvent which does not dissolve, and the solvent present near the surface of the developed precursor polyamide film is evaporated in the air to form a dense layer on the surface side After that, there is a method of forming a fine porous layer on the bath side.

  When such an asymmetric membrane is used for a gas separation membrane, the dense layer has different permeation rates depending on gas species, and plays a role of separating mixed gas, while the porous layer is for maintaining the membrane shape. It can serve as a support.

  The asymmetric membrane having a fluorine-containing heterocyclic structure, which is used for the gas separation membrane of the present invention, may be in the form of a flat membrane or a hollow fiber, and after forming, it is heated and the cyclization reaction is carried out It can be manufactured by advancing it.

  The thickness of the dense layer in the asymmetric film is preferably 10 nm or more and 10 μm or less. If it is thinner than 10 nm, it is difficult to form a film and it is not practical. If it is thicker than 10 μm, gas can not easily permeate. Preferably it is 30 nm or more and 1 μm or less.

  The thickness of the porous layer in the asymmetric membrane is preferably 5 μm or more and 2 mm or less for a flat membrane. If it is thinner than 5 μm, it is difficult to form a film and it is not practical. If it is thicker than 2 mm, gas can not easily permeate. Preferably they are 10 micrometers or more and 500 micrometers or less. In the case of hollow fiber, it is preferable to use a dense layer on the outside and a porous layer on the inside. The hollow fiber has an inner diameter of 10 μm to 4 mm, preferably 20 μm to 1 mm, and an outer diameter of 30 μm to 8 mm, preferably 50 μm to 1.5 mm. It is difficult to produce a hollow fiber having an inner diameter of 10 μm and an outer diameter of less than 30 μm. Hollow fibers having an inner diameter of 1 mm and an outer diameter of greater than 8 mm are not practical as gas separation membranes.

  Water or a water-based coagulating solution which is a mixed solution of water and an organic solvent is preferably used as the coagulating solution when producing an asymmetric membrane. The mixed solution preferably contains 30% by weight or more and 90% by weight or less, preferably 40% by weight or more and 80% by weight or less of water based on the total weight of the mixed solution. Examples of the organic solvent to be used include methanol, ethanol or isopropanol as an alcohol solvent, acetone, methyl ethyl ketone or diethyl ketone as a ketone solvent.

  A precursor polyamide solution of a polymer compound having a fluorine-containing heterocyclic ring used for the gas separation membrane of the present invention has N, N-dimethylformamide as an amide-based solvent by having an HFIP group which is a polar group in the structure, It is particularly easy to dissolve in N, N-dimethylacetamide or N-methyl-2-pyrrolidone, γ-butyrolactone as a lactone solvent and γ-valerolactone, and it is easy to prepare a film having a desired uniform film thickness. is there. In addition, it is easy to produce an asymmetric membrane using the aqueous coagulating solution.

  When preparing a membrane with an asymmetric structure, change the distance from the discharge port to the coagulation bath, and when discharging in the form of hollow fibers, discharge dry air, water-based coagulation liquid, etc. together inside the discharge port. Thus, an asymmetric membrane having a desired dense layer and porous layer can be formed, and a porous layer having a desired pore size, pore size distribution, and thickness can be formed by changing the type of organic solvent in the coagulation bath. be able to.

The membrane immersed in the coagulating solution can be used as a gas separation membrane after being heated, and drying and advancing the cyclization reaction. The heating temperature at that time is preferably 100 ° C. or more and 400 ° C. or less. More preferably, the temperature is 150 ° C. or more and 350 ° C. or less. When the heating temperature is lower than 100 ° C., the drying and cyclization reaction of the solvent can not be sufficiently performed, and when the heating temperature is higher than 400 ° C., the glass transition temperature is exceeded and the asymmetric structure of the polymer film may be impaired.
6. Composition of Material of Gas Separation Membrane The gas separation membrane of the above [Invention 1] is a gas separation membrane containing a polymer compound having a repeating unit represented by the general formula (1).

  The polymer compound contained in the gas separation membrane of [Invention 2] is a polymer compound in which the content of the repeating unit represented by the general formula (1) is 90% by mass or more based on the total amount of the polymer compound.

  The high molecular compound which the gas separation membrane of [Invention 3] contains is a high molecular compound which consists only of the repeating unit represented by General formula (1).

  The content of the repeating unit represented by the general formula (1) with respect to the total amount of the polymer compound is preferably 90% by mass or more, more preferably 95% by mass or more, and preferably 98% by mass or more May be The balance is a diamine compound which does not belong to the general formula (1B), and is preferably an “other diamine compound” which does not contain a protic acid group.

  Specifically, the gas separation membrane of [Invention 4] is a gas separation membrane of Inventions 1 to 3 including a polymer compound containing a repeating unit represented by the following formula (2A).

  Specifically, the gas separation membrane of [Invention 5] is the gas separation membrane of Inventions 1 to 3 including a polymer compound having a repeating unit represented by the following formula (3A).

  Specifically, the gas separation membrane of [Invention 6] is the gas separation membrane of Inventions 1 to 3 including a polymer compound having a repeating unit represented by the following formula (4A).

  Specifically, the gas separation membrane of [Invention 7] is the gas separation membrane of Inventions 1 to 3 including a polymer compound having a repeating unit represented by the following Formula (5A).

  The gas separation membrane of [Invention 8] is the gas separation membrane of Inventions 1 to 3 including the polymer compound having the repeating unit (6A) represented by the following formula.

  The gas separation membrane of the above [invention 9] is the gas separation membrane of the first to third aspects specifically including a polymer compound having a repeating unit represented by the following formula (7A).

  The gas separation membrane of [Invention 10] is the gas separation membrane of Inventions 1 to 3 specifically including a polymer compound having a repeating unit represented by the following formula (8A).

  The gas separation membrane of the [invention 11] is the gas separation membrane of the first to third aspects, which specifically includes a polymer compound having a repeating unit represented by the following formula (9A).

The degree of polymerization of the polymer compound contained in the gas separation membrane of the present invention is preferably 30,000 or more and 500,000 or less in terms of the weight average molecular weight of the precursor polyamide. If the degree of polymerization is less than 30,000, a tough membrane can not be formed, and if it is more than 500,000, the obtained membrane is difficult to dissolve in the solution, and a polyamide precursor solution can hardly be produced, or a viscous membrane even if a polyamide precursor solution is produced. As a result, it is difficult to form a film.
7. Gas Separation Method The gas separation membrane of the present invention can be used for gas separation and recovery from a mixed gas, and for gas separation and purification. The mixed gas is, for example, hydrogen, helium, carbon monoxide, carbon dioxide, hydrogen sulfide, oxygen, nitrogen, ammonia, sulfur oxides, nitrogen oxides, methane as a hydrocarbon, ethane or propane, as an unsaturated hydrocarbon. A mixed gas containing propylene or tetrafluoroethane which is a perfluoro compound can be exemplified. The gas separation membrane of the present invention can be used as a gas separation membrane capable of efficiently separating a specific gas from these mixed gases, and in particular from a mixed gas containing carbon dioxide and a hydrocarbon such as carbon dioxide and methane. It can be used to selectively separate carbon dioxide.

  The pressure for permeating carbon dioxide to the gas separation membrane is preferably 0.12 MPa or more and 10 MPa or less, and more preferably 0.15 MPa or more and 7 MPa or less. Further, the temperature at the time of permeating carbon dioxide to the gas separation membrane is preferably -30 ° C or more and 90 ° C or less, and more preferably 15 ° C or more and 70 ° C or less.

EXAMPLES The present invention will be more specifically described below with reference to examples, but the present invention is not limited to these examples.
Example 1
[Preparation of precursor polyamide (1) solution and film formation of film of polymer compound (1)]
In a three-necked flask with an internal volume of 300 mL equipped with a nitrogen introduction tube, HFIP-MDA as a diamine containing HFIP group shown in the following reaction formula, 7.5 g (14.1 mmol), dimethylacetamide as a solvent (hereinafter DMAc and 42 g was added and stirred for 20 minutes at a temperature of −78 ° C. under a nitrogen atmosphere. Isophthalic acid chloride, 2.86 g (14.1 mmol) is dissolved in 8 g of DMAc, added, and stirred for 10 minutes at a temperature of −78 ° C. using a low temperature constant temperature reaction tank, then the bottom of the flask is put in an ice bath and stirred for 3 hours Then, it was stirred at room temperature for 2 hours to prepare a solution containing polyamide (1) as a precursor. Gel permeation chromatography (hereinafter sometimes referred to as GPC) apparatus (manufactured by Tosoh Corporation, model name HLC-8320GPC, column name: TSKgel Super HZM-H, solvent: tetrahydrofuran (hereinafter sometimes referred to as THF)) The molecular weight of the precursor polyamide (1) was measured, and the molecular weight of the precursor polyamide (1) was weight average molecular weight (Mw) = 156000 and weight average molecular weight / number average molecular weight (Mw / Mn) = 1.87. The

  The solution of the obtained precursor polyamide (1) is subjected to pressure filtration, then developed on a glass substrate, and after reaching a rotational speed of 300 rpm in 10 seconds with a spin coater, held at a rotational speed of 300 rpm for 10 seconds It applied so that it might become uniform thickness on a substrate. After heating for cyclization reaction at a temperature of 300 ° C. for 1 hour in a nitrogen atmosphere, the film was cooled, and the film was peeled from the glass substrate to obtain a film of a polymer compound (1). It was 29 micrometers when the film thickness of the film | membrane of a high molecular compound (1) was measured with Nikon Corporation make digital length measuring machine, model name: DIGIMICRO MH-15.

  The reaction pathway of the polymer compound (1) contained in the gas separation membrane of the present invention is shown in the following reaction formula.

Example 2
[Preparation of precursor polyamide (2) solution and film formation of polymer compound (2)]
To a three-necked flask with an internal volume of 300 mL equipped with a nitrogen introduction tube, add 7.5 g (14.1 mmol) of HFIP-MDA as a diamine containing an HFIP group shown in the following reaction formula, 42 g of DMAc as a solvent, Under an atmosphere, the mixture was stirred at a temperature of −78 ° C. for 20 minutes using a low temperature constant temperature reaction tank. Dissolve terephthalic acid chloride, 2.86 g (14.1 mmol) in 8 g of DMAc, and stir for 10 minutes at a temperature of -78 ° C, then immerse the bottom of the flask in an ice bath and stir for 3 hours, then at room temperature 2 The mixture was stirred for a period of time to prepare a solution containing polyamide (2) as a precursor. When the molecular weight of precursor polyamide (2) was measured with the above-mentioned GPC apparatus, the molecular weight of precursor polyamide (2) was Mw = 85700 and Mw / Mn = 1.68.

  The solution of the obtained precursor polyamide (2) is subjected to pressure filtration, then developed on a glass substrate, and after reaching a rotational speed of 300 rpm in 10 seconds with a spin coater, held for 10 seconds at a rotational speed of 300 rpm It applied so that it might become uniform thickness on a substrate. After heating for cyclization reaction at a temperature of 300 ° C. for 1 hour in a nitrogen atmosphere, the film was cooled, and the film was peeled from the glass substrate to obtain a film of a polymer compound (2). It was 20 micrometers when the film thickness of the film | membrane of a high molecular compound (2) was measured with the above-mentioned length measuring machine.

  The synthetic route of the polymer compound (2) in the above operation is shown in the following reaction formula.

Example 3
[Preparation of precursor polyamide (3) solution and film formation of polymer compound (3)]
To a three-necked flask with an internal volume of 300 mL equipped with a nitrogen introduction tube, add 7.5 g (14.1 mmol) of HFIP-MDA as a diamine containing an HFIP group shown in the following reaction formula, 42 g of DMAc as a solvent, Under an atmosphere, the mixture was stirred at a temperature of −78 ° C. for 20 minutes using a low temperature constant temperature reaction tank. Dissolve and add 4,4'-biphenyl carbonyl chloride, 3.94 g (14.1 mmol) in 8 g of DMAc and stir at a temperature of -78 ° C for 10 minutes, then immerse the bottom of the flask in an ice bath and stir for 3 hours Then, the mixture was stirred at room temperature for 2 hours to prepare a solution containing polyamide (3) as a precursor. When the molecular weight of the precursor polyamide (3) was measured by the above-mentioned GPC apparatus, the molecular weight of the precursor polyamide (3) was Mw = 62,400 and Mw / Mn = 1.67.

  The solution of the obtained precursor polyamide (3) is subjected to pressure filtration, then developed on a glass substrate, and after reaching a rotational speed of 300 rpm in 10 seconds with a spin coater, held at a rotational speed of 300 rpm for 10 seconds It applied so that it might become uniform thickness on a substrate. After heating for cyclization reaction at a temperature of 300 ° C. for 1 hour in a nitrogen atmosphere and cooling, the film was peeled from the glass substrate to obtain a film of a polymer compound (3). It was 18 micrometers when the film thickness of the film of a high molecular compound (3) was measured with the above-mentioned side machine.

  The synthetic route of the polymer compound (3) in the above operation is shown in the following reaction formula.

Example 4
[Preparation of precursor polyamide (4) solution and film formation of polymer compound (4)]
In a three-necked flask with an internal volume of 300 mL equipped with a nitrogen introduction tube, HFIP-mTB as a diamine containing an HFIP group shown in the following reaction formula, 21.8 g (40.0 mmol), dimethylacetamide as a solvent (hereinafter DMAc and 60 g was added and stirred at a temperature of −78 ° C. for 20 minutes under a nitrogen atmosphere. Dissolve 11.8 g (40.0 mmol) of 4,4'-oxybis (benzoyl chloride) (hereinafter sometimes referred to as OBBC) in 70 g of DMAc and add, and use a low-temperature constant temperature reaction tank to obtain a temperature of -78 ° C. After stirring for 10 minutes, the bottom of the flask was placed in an ice bath and stirred for 3 hours, and then stirred at room temperature for 2 hours to prepare a solution containing polyamide (4) as a precursor. Gel permeation chromatography (hereinafter sometimes referred to as GPC) apparatus (manufactured by Tosoh Corporation, model name HLC-8320GPC, column name: TSKgel Super HZM-H, solvent: tetrahydrofuran (hereinafter sometimes referred to as THF)) The molecular weight of the precursor polyamide (4) was measured, and the molecular weight of the precursor polyamide (4) was weight average molecular weight (Mw) = 227700, and weight average molecular weight / number average molecular weight (Mw / Mn) = 1.83. The

  The solution of the obtained precursor polyamide (4) is subjected to pressure filtration, then developed on a glass substrate, and after reaching a rotational speed of 500 rpm in 10 seconds with a spin coater, held at a rotational speed of 500 rpm for 10 seconds It applied so that it might become uniform thickness on a substrate. After heating for cyclization reaction at a temperature of 250 ° C. for 1 hour in a nitrogen atmosphere, the film was cooled and the film was peeled from the glass substrate to obtain a film of a polymer compound (4). It was 45 micrometers when the film thickness of the film | membrane of a high molecular compound (4) was measured with the above-mentioned length measuring machine.

  The reaction pathway of the polymer compound (4) contained in the gas separation membrane of the present invention is shown in the following reaction formula.

Example 5
[Preparation of precursor polyamide (5) solution and film formation of polymer compound (5)]
To a 300 mL three-necked flask equipped with a nitrogen introduction tube, add 7.5 g (13.8 mmol) of HFIP-mTB as a diamine containing an HFIP group shown in the following reaction formula, 42 g of DMAc as a solvent, and nitrogen atmosphere Below, it stirred for 20 minutes at the temperature of -78 degreeC using a low temperature isothermal reaction tank. Isophthalic acid chloride, 2.80 g (13.8 mmol) is dissolved in 8 g of DMAc and added, and stirred at a temperature of −78 ° C. for 10 minutes, then the bottom of the flask is immersed in an ice bath and stirred for 3 hours; The mixture was stirred for a period of time to prepare a solution containing polyamide (5) as a precursor. When the molecular weight of precursor polyamide (4) was measured with the above-mentioned GPC apparatus, the molecular weight of precursor polyamide (5) was Mw = 43100 and Mw / Mn = 1.69.

  The solution of the obtained precursor polyamide (5) is subjected to pressure filtration, then developed on a glass substrate, and after reaching a rotation number of 300 rpm in 10 seconds with a spin coater, held for 10 seconds at a rotation number of 300 rpm It applied so that it might become a film of uniform thickness on a substrate. Under a nitrogen atmosphere, the mixture was heated at a temperature of 300 ° C. for 1 hour to cause cyclization reaction, followed by cooling, and the film was peeled from the glass substrate to obtain a film of a polymer compound (5). It was 13 micrometers when the film thickness of the film of a high molecular compound (5) was measured with the above-mentioned length measuring machine.

  It shows in the following reaction formula of the synthetic pathway of a high molecular compound (5) in the above operation.

Example 6
[Preparation of precursor polyamide (6) solution and film formation of polymer compound (6)]
To a three-necked flask with an internal volume of 300 mL equipped with a nitrogen introducing tube, add 7.5 g (13.8 mmol) of HFIP-mTB as a diamine containing an HFIP group shown in the following reaction formula, 42 g of DMAc as a solvent, The mixture was stirred at a temperature of −78 ° C. for 20 minutes under an atmosphere. Isophthalic acid chloride, 1.40 g (6.9 mmol) and terephthalic acid chloride, 1.40 g (6.9 mmol) are dissolved in 8 g of DMAc and added, and the temperature is kept at −78 ° C. for 10 minutes using a low temperature thermostatic reaction tank. After stirring, the bottom of the flask was immersed in an ice bath and stirred for 3 hours, and then stirred at room temperature for 2 hours to prepare a solution containing a precursor polyamide (6) as a precursor. The molecular weight of the precursor polyamide (6) was measured by the above-mentioned GPC apparatus, and the molecular weight of the polyamide (6) was Mw = 79800 and Mw / Mn = 1.76.

  The solution of the obtained precursor polyamide (6) is subjected to pressure filtration, then developed on a glass substrate, and after reaching a rotation number of 300 rpm in 10 seconds with a spin coater, held at a rotation number of 300 rpm for 10 seconds It applied so that it might become uniform thickness on a substrate. After heating for cyclization reaction at a temperature of 300 ° C. for 1 hour in a nitrogen atmosphere, the film was cooled and the film was peeled from the glass substrate to obtain a film of a polymer compound (6). It was 28 micrometers when the film thickness of the film of a high molecular compound (6) was measured with the above-mentioned side machine.

  The synthesis route of the polymer compound (6) in the above operation is shown in the following reaction formula.

Example 7
[Preparation of precursor polyamide (7) solution and formation of film of polymer compound (7)]
To a three-necked flask with an internal volume of 300 mL equipped with a nitrogen introducing tube, add 7.5 g (13.8 mmol) of HFIP-mTB as a diamine containing an HFIP group shown in the following reaction formula, 42 g of DMAc as a solvent, The mixture was stirred at a temperature of −78 ° C. for 20 minutes under an atmosphere. Isophthalic acid chloride, 1.40 g (6.9 mmol) and 4,4'-biphenyl carbonyl chloride, 1.93 g (6.9 mmol) were dissolved in 8 g of DMAc and added, and stirred at a temperature of -78 ° C for 10 minutes Thereafter, the bottom of the flask was immersed in an ice bath and stirred for 3 hours, and then stirred at room temperature for 2 hours to prepare a solution containing a precursor polyamide (7) as a precursor. When the molecular weight of precursor polyamide (7) was measured with the above-mentioned GPC apparatus, it was Mw = 57300 and Mw / Mn = 1.87.

  The solution of the obtained precursor polyamide (7) is subjected to pressure filtration, then developed on a glass substrate, and after reaching a rotational speed of 300 rpm in 10 seconds with a spin coater, held at a rotational speed of 300 rpm for 10 seconds, It applied so that it might become a film of uniform thickness on top. After heating for cyclization reaction at a temperature of 300 ° C. for 1 hour in a nitrogen atmosphere, the film was cooled and the film was peeled from the glass substrate to obtain a film of a polymer compound (7). When the film thickness of the polymer compound film (7) was measured by the above-mentioned length measuring machine, the film thickness was 21 μm.

  The synthesis route of the polymer compound (7) in the above operation is shown in the following reaction formula.

Example 8
[Preparation of precursor polyamide (8) solution and membrane formation of polymer compound (8)]
In a three-necked flask with an internal volume of 300 mL equipped with a nitrogen introduction tube, HFIP-mTB as a diamine containing an HFIP group shown in the following reaction formula, 21.8 g (40.0 mmol), dimethylacetamide as a solvent (hereinafter DMAc and 60 g was added and stirred at a temperature of −78 ° C. for 20 minutes under a nitrogen atmosphere. After dissolving 11.8 g (40.0 mmol) of OBBC in 70 g of DMAc and stirring for 10 minutes at a temperature of −78 ° C. using a low temperature constant temperature reaction tank, place the bottom of the flask in an ice bath and stir for 3 hours, Subsequently, it stirred at room temperature for 2 hours, and prepared the solution containing polyamide (8) used as a precursor. Gel permeation chromatography (hereinafter sometimes referred to as GPC) apparatus (manufactured by Tosoh Corporation, model name HLC-8320GPC, column name: TSKgel Super HZM-H, solvent: tetrahydrofuran (hereinafter sometimes referred to as THF)) When the molecular weight of the precursor polyamide (8) was measured, the molecular weight of the precursor polyamide (1) was weight average molecular weight (Mw) = 134200 and weight average molecular weight / number average molecular weight (Mw / Mn) = 1.81. The

  The solution of the obtained precursor polyamide (8) is subjected to pressure filtration, then developed on a glass substrate, and after reaching a rotational speed of 800 rpm in 10 seconds with a spin coater, held at a rotational speed of 800 rpm for 10 seconds It applied so that it might become uniform thickness on a substrate. After heating for cyclization reaction by heating at a temperature of 250 ° C. for 1 hour in a nitrogen atmosphere, the film was cooled, and the film was peeled from the glass substrate to obtain a film of a polymer compound (8). It was 68 micrometers when the film thickness of the film | membrane of a high molecular compound (8) was measured with the above-mentioned length measuring machine.

  The reaction pathway of the polymer compound (8) contained in the gas separation membrane of the present invention is shown in the following reaction formula.

Comparative Example 1
[Preparation and Film Formation of Polymer Compound (9)]
In a 500 mL three-necked flask equipped with a nitrogen introduction tube, 58.3 g (110 mmol) of HFIP-MDA represented by the following reaction formula, and 3,3 ', 4,4'-biphenyltetracarboxylic acid dianhydride ( In the following, 32.4 g (110 mmol) and DMAc (220 g) were added, which may be referred to as BPDA), and stirred at a temperature of 20 ° C. for 20 minutes under a nitrogen atmosphere. Next, 34.8 g (440 mmol) of pyridine and 44.9 g (440 mmol) of acetic anhydride were sequentially added to the reaction system, and the mixture was further stirred for 24 hours to carry out imidation reaction to prepare a solution containing a polymer compound (9). When the molecular weight was measured by the above-mentioned GPC apparatus, it was Mw = 91000 and Mw / Mn = 1.84.

  The solution of the obtained polymer compound (9) is subjected to pressure filtration, then developed on a glass substrate, and after reaching a rotation number of 800 rpm in 10 seconds with a spin coater, held at a rotation number of 800 rpm for 10 seconds It applied so that it might become uniform thickness on a substrate. After heating at a temperature of 300 ° C. for 2 hours in a nitrogen atmosphere and cooling, the film was peeled from the glass substrate to obtain a film of a polymer compound (9) consisting only of repeating units shown in the following reaction formula. It was 43 micrometers when the film thickness of the film | membrane of a high molecular compound (7) was measured with the above-mentioned long machine.

  The synthetic route of the polymer compound (9) in the above operation is shown in the following reaction formula. The polymer compound (9) has no heterocyclic structure.

Comparative example 2
[Preparation and film formation of polymer compound (10)]
In a 500 mL three-necked flask equipped with a nitrogen introduction tube, add 60.0 g (110 mmol) of HFIP-mTB, 32.4 g (110 mmol) of BPDA, 220 g of DMAc shown in the following reaction formula, and under a nitrogen atmosphere The mixture was stirred at a temperature of 20 ° C. for 20 minutes. Then, 34.8 g (440 mmol) of pyridine and 44.9 g (440 mmol) of acetic anhydride were sequentially added to the reaction system, and the mixture was further stirred for 24 hours to carry out imidation reaction to prepare a solution containing a polymer compound (10). When the molecular weight was measured by the above-mentioned GPC apparatus, it was Mw = 134000 and Mw / Mn = 1.97.

  The resulting solution containing the polymer compound (10) is diluted with 150 g of DMAc, and after pressure filtration, the solution is developed on a glass substrate and developed with a spin coater for 10 seconds, and the rotation speed of 1200 rpm is reached. It hold | maintained for 10 seconds at 1200 rpm, and apply | coated so that it might become uniform thickness on a glass substrate. After heating at a temperature of 300 ° C. for 2 hours in a nitrogen atmosphere, the film was cooled and the film was peeled from the glass substrate to obtain a film of a polymer compound (10). It was 51 micrometers when the film thickness of the film of a high molecular compound (10) was measured with the above-mentioned side machine.

  The synthetic route of the polymer compound (10) in the above operation is shown in the following reaction formula. The polymer compound (10) does not have a heterocyclic structure.

Comparative example 3
[Preparation and Film Formation of Polymer Compound (11)]
7.5 g (13.8 mmol) of HFIP-mTB shown in the following reaction formula and 15 g of DMAc are added to a three-necked flask with an inner volume of 300 mL equipped with a nitrogen introduction tube, and a low temperature thermostatic reaction tank is used under a nitrogen atmosphere. The mixture was stirred at a temperature of −78 ° C. for 20 minutes. Next, 1.40 g (6.89 mmol) of isophthalic acid chloride was added and stirred for 10 minutes at a temperature of -78 ° C, and then the bottom of the flask was placed in an ice bath and stirred for 3 hours. Thereafter, BPDA, 2.03 g (6.89 mmol), DMAc, 2 g were sequentially added and stirred at room temperature for 2 hours. To the reaction system, 2.18 g (27.6 mmol) of pyridine, acetic anhydride, 2.82 g (27.6 mmol) were added in this order, and the mixture was further stirred for 24 hours to prepare a solution containing polyamideimide (11). When molecular weight was measured with the above-mentioned GPC apparatus, it was Mw = 52,400 and Mw / Mn = 1.66.

  After pressure-filtering the solution containing the obtained polyamidoimide (11), it apply | coated to the glass substrate. After spreading on a glass substrate and reaching 500 rpm with a spin coater in 10 seconds, it was held at 500 rpm for 10 seconds and coated on a glass substrate so as to have a uniform thickness. After heating at a temperature of 300 ° C. for 1 hour in a nitrogen atmosphere, the film was cooled, and the film was peeled from the glass substrate to obtain a film of the polymer compound (11). It was 47 micrometers when the film thickness of the film | membrane of a high molecular compound (11) was measured with the above-mentioned long machine.

  The synthetic route of the polymer compound (11) in the above operation is shown in the following reaction formula. The polymer compound (11) has both an HFIP group and a heterocyclic structure.

  The polymer compounds (1) to (4) and (6) to (8) containing the heterocyclic structure of the present invention in Examples 1 to 8 are shown in Table 1 below, according to Comparative Examples 1 to 3 of the present invention. Polymer compounds (9) to (11) not included in the category are shown in Table 2 below.

  The polymer compounds (1) to (4) of Examples 1 to 4 of the present invention and the polymer compound (9) of Comparative Example 1 not included in the category of the present invention used the HFIP-MDA as a raw material compound. It is a polymer compound. When the polymer compounds (6) to (8) of Examples 6 to 8 of the present invention and the polymer compounds (10) to (11) of Comparative Examples 2 to 3 not included in the category of the present invention were used as raw material compounds. It is a polymer compound using the HFIP-mTB.

The polymer compound (6) of Example 6, the polymer compound (7) of Example 7, and the polymer compound (11) of Comparative Example 3 are isophthalic acid relative to 1 mole of diamine having a HFIP group as a raw material compound. Acid chloride, 0.5 molar equivalents, and 0.5 molar equivalents of each dicarboxylic acid derivative or 0.5 molar equivalents of tetracarboxylic acid dianhydride are used, corresponding to the equivalent ratio of the starting compounds It has a structure derived from each raw material in proportion. The polymer compounds (9) to (11) of Comparative Examples 1 to 3 have a polyimide structure having an HFIP group derived from BPDA which is a tetracarboxylic acid dianhydride.
[Method of evaluating transparency]
The permeability was evaluated by a differential pressure type pressure gauge method using a gas permeability measuring device (GTR-2ADF manufactured by GTR Tech Co., Ltd.).

Specifically, a gas separation membrane having a membrane area of 3.14 cm ² is disposed in a stainless steel cell, and hydrogen gas (H ₂ ), helium gas (He), methane gas (CH ₄ ), and the like at a temperature of 35 ° C. Using carbon dioxide gas (CO ₂ ), nitrogen gas (N ₂ ) and oxygen gas (O ₂ ), the permeation coefficient of each gas was measured at a supply gas pressure of 150 kPa. The gas selectivity was calculated from the permeability coefficients of two types of gas.
[Measurement of Permeability Coefficient of Membrane Composed of Polymer Compounds (1) to (4) of Examples 1 to 4 and Membrane Composed of Polymer Compound (9) of Comparative Example 1 and Selectivity of Membrane Calculated From It]
The measurement results of the permeability of the membranes comprising the polymer compounds (1) to (4) of Examples 1 to 4 and the polymer compound (9) of Comparative Example 1 are shown in Table 3.

The selectivity of the gas calculated from the permeation coefficients of Table 3 is shown in Table 4.

Hereinafter, Table 3 and Table 4 will be described.
<Transmittance coefficient>
In all the measured gases, the permeability coefficient of the membrane composed of the polymer compounds (1) to (4) using HFIP-MDA of Examples 1 to 4 is the polymer compound which is the fluorine-containing polyimide compound of Comparative Example 1 It was higher than the permeability coefficient of the membrane consisting of (9).
<Permeability of carbon dioxide>
The permeability coefficient of CO ₂ of the films of the polymer compounds (1) to (4) of Examples 1 to 3 was higher than the permeability coefficient of CO ₂ of the polymer compound (9) of Comparative Example 1.
<Permeability of methane>
The permeation coefficient of CH ₄ of the films of the polymer compounds (1) to (4) of Examples 1 to ₃ was higher than that of CH ₄ of the polymer compound (9) of Comparative Example 1.
<Selectivity of carbon dioxide and methane>
The selectivity CO ₂ / CH ₄ of the membrane composed of the polymer compounds (1) to (4) of Examples 1 to ₄ is similar to the selectivity of the membrane composed of the polymer compound (9) of Comparative Example 1 , Showed sufficient selectivity as a gas separation membrane. The film composed of the polymer compounds (1) to (4) of Examples 1 to 4 in which the permeability is excellent compared to the film composed of the polymer compound (9) of Comparative Example 1 has a smaller membrane area in a short time It is possible to separate and process gases containing higher amounts of CO ₂ and CH ₄ .
<Permeability of nitrogen>
The permeability coefficient of N ₂ of the membranes of the polymer compounds (1) to (4) of Examples 1 to 4 was higher than the permeability coefficient of CO ₂ of the polymer compound (7) of Comparative Example 1.
<Selectivity of carbon dioxide and nitrogen>
The selectivity CO ₂ / N ₂ of the membrane comprising the polymer compound (1), the polymer compound (2) and the polymer compound (4) of Example 1, Example 2 and Example 4 is as high as that of Comparative Example 1. It was superior to the selectivity of the membrane composed of the molecular compound (9). The selectivity CO ₂ / N ₂ of the membrane composed of the polymer compound (3) of Example 3 is comparable to the selectivity of the membrane composed of the polymer compound (9) of Comparative Example 1, and as a gas separation membrane It showed sufficient selectivity.

The film composed of the polymer compounds (1) to (4) of Examples 1 to 4 in which the permeability is excellent compared to the film composed of the polymer compound (9) of Comparative Example 1 has a smaller membrane area in a short time It is possible to separate and process a gas containing a large amount of CO ₂ and N ₂ .
<Permeability of helium>
The permeability coefficient of He of the films of the polymer compounds (1) to (4) of Examples 1 to 4 was higher than that of He of the polymer compound (9) of Comparative Example 1.
<Selectivity of Helium and Methane>
The selectivity He / CH ₄ of the film comprising the polymer compound (1) and the polymer compound (4) of Example 1 and Example ₄ is based on the selectivity of the film comprising the polymer compound (9) of Comparative Example 1 It was excellent. The selectivity He / CH ₄ of the film comprising the polymer compound (2) and the polymer compound (3) of Example 2 and Example 3 is the selectivity of the film comprising the polymer compound (9) of Comparative Example 1 and It was comparable and showed sufficient selectivity as a gas separation membrane.

The film composed of the polymer compounds (1) to (4) of Examples 1 to 4 in which the permeability is excellent compared to the film composed of the polymer compound (9) of Comparative Example 1 has a smaller membrane area in a short time It is possible to separate and process a gas containing a larger amount of He and CH ₄ .
[Measurement of Permeability Coefficient of Membrane Composed of Polymer Compounds (6) to (8) of Examples 6 to 8 and Membrane Composed of Polymer Compounds (10) to (11) of Comparative Examples 2 to 3 and Calculated From It [Selectivity of Membrane] Table 1 shows the results of measurement of gas permeability of membranes comprising the high molecular compounds (6) to (8) of Examples 4 to 5 and the high molecular compounds (10) to (11) of Comparative Examples 2 to 3. Shown in 5.

The selectivity of the gas calculated from the permeation coefficients of Table 5 is shown in Table 6.

Hereinafter, Table 5 and Table 6 will be described.
<Transmittance coefficient>
The permeability coefficients of the films comprising the polymer compounds (6) to (8) using HFIP-mTB in Examples 6 to 8 are the polymer compounds (10) to ((6)) which are the fluorine-containing polyimide compounds of Comparative Examples 2 to 3. The permeability coefficient of the membrane consisting of 11) was higher.
<Permeability of carbon dioxide>
The permeability coefficients of the polymer compounds (6) to (8) of Examples 6 to 8 were higher than the permeability coefficient of CO ₂ composed of the polymer compounds (10) to (11) of Comparative Examples 2 to 3.
<Permeability of methane>
The permeability coefficients of the polymer compounds (10) to (11) of Examples 6 to 8 were higher than the permeability coefficient of CH ₄ composed of the polymer compounds (10) to (11) of Comparative Examples 2 to 3.
<Selectivity of carbon dioxide and methane>
With regard to the selectivity of carbon dioxide and methane, the selectivity CO ₂ / CH ₄ of the membranes comprising the polymer compounds (6) to (8) of Examples 6 to 8 and the polymer compounds of Comparative Examples 2 to 3 (10 Although the selectivity of the membrane consisting of (1) to (11) is lower, it shows sufficient selectivity as a gas separation membrane.
The membranes composed of the polymer compounds (6) to (8) of Examples 6 to 8 which are superior in permeability to the membranes composed of the polymer compounds (10) to (11) of Comparative Examples 2 to 3 are smaller. Even the membrane area can separate and process a gas containing a large amount of CO ₂ and CH ₄ in a short time.
<Permeability of nitrogen>
Transmission of Examples 6-8 of the polymer compound (6) to the transmission coefficient of the polymer compound of Comparative Example 2-3 N ₂ membrane made of (8) (10) to the film made of (11) N ₂ It was higher than the coefficient.
<Selectivity of carbon dioxide and nitrogen>
The selectivity CO ₂ / N ₂ of the membrane composed of the polymer compounds (6) to (8) of Examples 6 to 8 is the selection of the membrane composed of the polymer compounds (10) to (11) of Comparative Examples 2 to 3. Although it is less than sex, it shows sufficient selectivity as a gas separation membrane.
The membranes composed of the polymer compounds (6) to (8) of Examples 6 to 8 which are superior in permeability to the membranes composed of the polymer compounds (10) to (11) of Comparative Examples 2 to 3 are smaller. Even the membrane area can separate and process a gas containing a large amount of CO ₂ and N ₂ in a short time.
<Permeability of helium>
Permeability Coefficients of Membranes Composed of Polymer Compounds (6) to (8) of Examples 6 to 8 The permeability coefficients of He composed of Polymer Compounds (10) to (11) of Comparative Examples 2 to 3 of Comparative Examples 2 to 3 were higher.
<Selectivity of Helium and Methane>
The selectivity He / CH ₄ of the films consisting of the polymer compounds (6) to (8) of Examples 6 to 8 is the selectivity of the films consisting of the polymer compounds (10) to (11) of Comparative Examples 2 to 3. Although it is lower, it shows sufficient selectivity as a gas separation membrane. The membranes composed of the polymer compounds (6) to (8) of Examples 6 to 8 which are superior in permeability to the membranes composed of the polymer compounds (10) to (11) of Comparative Examples 2 to 3 are smaller. The film area can also process the gas containing a larger amount of He and CH ₄ in a short time.

Claims (13)

General formula (1):

(Wherein, R ¹ is a single bond or a methylene chain, R ² is a hydrogen atom or a methyl group, and R ³ is any of the divalent groups represented by the following formulas (2) to (5) Organic group of

Containing a polymer compound having a repeating unit represented by
And, in the polymer compound, the number of hexafluoroisopropanol groups is 20% or less with respect to the total number of the following fluorine-containing heterocyclic structure (A).

Gas separation membrane. The polymer compound having a repeating unit represented by the general formula (1) is a polymer compound in which the content of the repeating unit represented by the general formula (1) with respect to the polymer compound is 90% by mass or more. The gas separation membrane according to claim 1. The gas separation membrane according to claim 1, wherein the polymer compound having a repeating unit represented by the general formula (1) is a polymer compound consisting only of the repeating unit represented by the general formula (1). In the general formula (1), R ¹ is a methylene chain, R ² is a hydrogen atom, and a divalent organic group R ³ is
Formula (2):

The gas separation membrane according to any one of claims 1 to 3, which is a group represented by In the general formula (1), R 1 is a methylene chain, R ² is a hydrogen atom, and a divalent organic group R ³ is
Formula (3):

The gas separation membrane according to any one of claims 1 to 3, which is a group represented by In the general formula (1), R ¹ is a methylene chain, R ² is a hydrogen atom, and a divalent organic group R ³ is
Formula (4):

The gas separation membrane according to any one of claims 1 to 3, which is a group represented by In the general formula (1), R ¹ is a methylene chain, R ² is a hydrogen atom, and a divalent organic group R ³ is
Formula (5):

The gas separation membrane according to any one of claims 1 to 3, which is a group represented by In the general formula (1), R ¹ is a single bond, R ² is a methyl group, and a divalent organic group R ³ is
Formula (2):

The gas separation membrane according to any one of claims 1 to 3, which is a group represented by In the general formula (1), R ¹ is a single bond, R ² is a methyl group, and a divalent organic group R ³ is
Formula (3):

The gas separation membrane according to any one of claims 1 to 3, which is a group represented by In the general formula (1), R ¹ is a single bond, R ² is a methyl group, and a divalent organic group R ³ is
Formula (4):

The gas separation membrane according to any one of claims 1 to 3, which is a group represented by In the general formula (1), R ¹ is a single bond, R ² is a methyl group, and a divalent organic group R ³ is
Formula (5):

The gas separation membrane according to any one of claims 1 to 3, which is a group represented by A gas separation method for separating carbon dioxide from a gas containing at least carbon dioxide using the gas separation membrane according to any one of claims 1 to 11. The method for separating gas according to claim 12 , wherein carbon dioxide is separated from gas containing at least hydrocarbon and carbon dioxide.