JP2017185462A - Gas separation membrane, gas separation module, gas separation device and gas separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas separation membrane capable of achieving gas permeability and gas separation selectivity at a desired high level and capable of persistently expressing the above excellent separation membrane performances (gas permeability, gas separation selectivity) even under existence of plasticization impurities, and to provide the gas separation module, gas separation device and gas separation method using the membrane.SOLUTION: There is provided a gas separation membrane having a gas separation layer containing a high molecular compound having the constitutional unit represented by formula (1) on a main chain (Zand Zare each independently a divalent connection group; Qis a divalent group including a sulfonamide group; Yis H, alkyl, aryl, alkoxy, alkylsulfone or dialkyl phosphine oxide; and n is an integer of 0 or more).SELECTED DRAWING: None

Description

  The present invention relates to a gas separation membrane, a gas separation module, a gas separation device, and a gas separation method.

  A material made of a polymer compound has a gas permeability unique to each material. Based on the property, a desired gas component can be selectively permeated and separated by a membrane composed of a specific polymer compound. As an industrial utilization mode of this gas separation membrane, it is related to the problem of global warming, and it is separated and recovered from a large-scale carbon dioxide generation source in a thermal power plant and / or a cement plant, a steelworks blast furnace, etc. Is being considered. And this membrane separation technique attracts attention as a means for solving environmental problems that can be achieved with relatively small energy. On the other hand, natural gas and biogas (gas generated by fermentation and anaerobic digestion of biological waste, organic fertilizer, biodegradable substances, sewage, garbage, energy crops, etc.) are mainly mixed gases containing methane and carbon dioxide. As a means for removing impurities such as carbon dioxide, a membrane separation method has been studied.

  In the purification of natural gas using a membrane separation method, excellent gas permeability and gas separation selectivity are required in order to separate gases more efficiently. Further, in an actual plant, the membrane is plasticized due to the influence of impurity components (for example, benzene, toluene, xylene) present in natural gas, and this causes a problem of reduction in gas separation selectivity. Therefore, the gas separation membrane is also required to have plastic resistance capable of continuously expressing desired gas separation selectivity even in the presence of the impurity component. In order to realize these, various membrane materials have been studied, and as part of this, the following gas separation membranes have been studied. For example, Patent Document 1 describes that a microporous membrane coated with polysulfonamide-polyurea is used as a gas separation layer of a gas separation membrane. Patent Document 2 describes that a resin membrane made of a fluorine-based copolymer having a sulfonamide group is used as a gas separation layer of a gas separation membrane.

In order to obtain a practical gas separation membrane, the gas separation layer must be made thin to ensure sufficient gas permeability, and a higher degree of gas separation selectivity must be realized. As a method for thinning the gas separation layer, a polymer compound that forms the gas separation layer responsible for the gas separation function is made into an asymmetric membrane by a phase separation method, and a portion contributing to the separation is called a dense layer or a skin layer. There is a way to layer. In this asymmetric membrane, a portion other than the dense layer is allowed to function as a support layer that bears the mechanical strength of the membrane.
In addition to the asymmetric membrane, the gas separation layer responsible for the gas separation function and the support layer responsible for the mechanical strength are made of different materials, and the gas separation layer having gas separation ability is thinly formed on the gas permeable support layer. The form of the composite film formed in the above is also known.

Special table 2011-522058 JP-A-5-329343

In general, gas permeability and gas separation selectivity are in a so-called trade-off relationship. Therefore, by adjusting the copolymerization component of the polymer compound used in the gas separation layer, either gas permeability or gas separation selectivity of the gas separation layer can be improved, but both characteristics are high as desired. It is difficult to achieve both levels.
Conventionally, the polymer compound used for the gas separation layer may not sufficiently cope with the problem of plastic resistance. In particular, when a polymer compound having high gas permeability is used for the gas separation layer, it becomes more susceptible to the above-mentioned impurity components, and the swelling of the gas separation layer is promoted.

  The present invention can achieve gas permeability and gas separation selectivity at a desired high level, and also provides the above excellent separation membrane performance (gas permeability and separation selectivity) even in the presence of plasticizing impurities. It is an object to provide a gas separation membrane that can be continuously expressed. Another object of the present invention is to provide a gas separation module, a gas separation device, and a gas separation method using the gas separation membrane.

  As a result of intensive studies in view of the above problems, the present inventors have used a polymer compound having a sulfonamide group introduced into the main chain structure (polysulfonamide compound) in the gas separation layer of the gas separation membrane. We found that both gas permeability and plasticization resistance can be achieved by overcoming the conventional trade-off relationship. Furthermore, it has been found that this gas separation membrane exhibits excellent gas separation selectivity even under high pressure conditions. The present invention has been further studied and completed based on these findings.

式（１）中、Ｚ^１、Ｚ^２はそれぞれ独立に二価の連結基を示し、Ｑ^１はスルホンアミド基を含む二価の基を示し、Ｙ^１は水素原子、アルキル基、アリール基又は式（３）〜式（５）のいずれかの基を示し、ｎは０以上の整数である。

式（３）〜式（５）中、Ｒ^３〜Ｒ^６はそれぞれ独立に、アルキル基又はアリール基を示す。＊１は、上記窒素原子との結合部位である。
［２］
上記高分子化合物を構成する上記式（１）で表される構成単位の一部又は全部が、下記式（７）で表される構成単位である［１］に記載のガス分離膜。

式（７）中、Ｚ^５〜Ｚ^６はそれぞれ独立に二価の連結基を示し、Ｙ^２、Ｙ^３はそれぞれ独立に水素原子、アルキル基、アリール基又は式（３）〜式（５）のいずれかの基を示す。

式（３）〜式（５）中、Ｒ^３〜Ｒ^６はそれぞれ独立に、アルキル基又はアリール基を示す。＊１は、上記窒素原子との結合部位である。
［３］
上記Ｚ^１〜Ｚ^２及びＺ^５〜Ｚ^６がそれぞれ独立に、アリーレン基を含む二価の基である、［１］又は［２］に記載のガス分離膜。
［４］
上記Ｚ^１〜Ｚ^２及びＺ^５〜Ｚ^６がそれぞれ独立に、下記式Ａ−１〜Ａ−１１のいずれかである、［１］又は［２］に記載のガス分離膜。

式中、Ｗ^１〜Ｗ^５０はそれぞれ独立に、水素原子、ハロゲン原子、アルキル基、アルコキシ基、水酸基又はカルボキシ基を示し、Ｚ^１１は−ＣＲ^８ _２−、−Ｏ−、−ＮＲ^８−、−Ｓ−又は単結合を示し、Ｌ^１〜Ｌ^２はそれぞれ独立に、−ＣＲ^９ _２−、−Ｏ−、−ＮＲ^９−、−Ｓ−又は単結合を示す。Ｒ^８は、水素原子、アルキル基又はアリール基を示す。Ｒ^９は、水素原子、アルキル基又はアリール基を示す。
［５］
上記ガス分離膜が、上記ガス分離層をガス透過性の支持層上側に有するガス分離複合膜である、［１］〜［４］のいずれか１つに記載のガス分離膜。
［６］
分離処理されるガスが二酸化炭素とメタンの混合ガスである場合において、４０℃、５ＭＰａにおける二酸化炭素の透過速度が２０ＧＰＵ超であり、二酸化炭素とメタンとの透過速度比（Ｒ_ＣＯ２／Ｒ_ＣＨ４）が１５以上である、［１］〜［５］のいずれか１つに記載のガス分離膜。
［７］
上記支持層が、ガス分離層側の多孔質層と、その逆側の不織布層とからなる、［１］〜［６］のいずれか１つに記載のガス分離膜。
［８］
二酸化炭素及びメタンを含むガスから二酸化炭素を選択的に透過させるために用いられる、［１］〜［７］のいずれか１つに記載のガス分離膜。
［９］
［１］〜［７］のいずれか１つに記載のガス分離膜を具備するガス分離モジュール。
［１０］
［９］に記載のガス分離モジュールを備えたガス分離装置。
［１１］
［１］〜［８］のいずれか１つに記載のガス分離膜を用いて、二酸化炭素及びメタンを含むガスから二酸化炭素を選択的に透過させるガス分離方法。 The above problem has been solved by the following means.
[1]
A gas separation membrane having a gas separation layer containing a polymer compound, wherein the polymer compound has a structural unit represented by the following formula (1) in the main chain.

In formula (1), Z ¹ and Z ² each independently represent a divalent linking group, Q ¹ represents a divalent group containing a sulfonamide group, Y ¹ represents a hydrogen atom, an alkyl group, an aryl group or The group in any one of Formula (3)-Formula (5) is shown, and n is an integer greater than or equal to 0.

In formula (3) to formula (5), R ^{3 to} R ⁶ each independently represents an alkyl group or an aryl group. * 1 is a binding site with the nitrogen atom.
[2]
The gas separation membrane according to [1], wherein a part or all of the structural unit represented by the formula (1) constituting the polymer compound is a structural unit represented by the following formula (7).

In Formula (7), Z ^{5 to} Z ⁶ each independently represent a divalent linking group, and Y ² and Y ³ are each independently a hydrogen atom, an alkyl group, an aryl group, or Formula (3) to Formula (5). Any one of these groups is shown.

In formula (3) to formula (5), R ^{3 to} R ⁶ each independently represents an alkyl group or an aryl group. * 1 is a binding site with the nitrogen atom.
[3]
The gas separation membrane according to [1] or [2], wherein Z ^{1 to} Z ² and Z ^{5 to} Z ⁶ are each independently a divalent group containing an arylene group.
[4]
The gas separation membrane according to [1] or [2], wherein Z ^{1 to} Z ² and Z ^{5 to} Z ⁶ are each independently any one of the following formulas A-1 to A-11.

In the formula, each of W ^{1 to} W ⁵⁰ independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a hydroxyl group, or a carboxy group, and Z ¹¹ represents —CR ⁸ ₂ —, —O—, —NR ⁸ —, indicates -S- or a single ^bond, the L 1 ~L ² are each _{^{independently, -CR 9 2 -, - O}} -, - NR 9 -, - S- or a single bond. R ⁸ represents a hydrogen atom, an alkyl group or an aryl group. R ⁹ represents a hydrogen atom, an alkyl group or an aryl group.
[5]
The gas separation membrane according to any one of [1] to [4], wherein the gas separation membrane is a gas separation composite membrane having the gas separation layer above the gas-permeable support layer.
[6]
In the case where the gas to be separated is a mixed gas of carbon dioxide and methane, the permeation rate of carbon dioxide at 40 ° C. and 5 MPa exceeds 20 GPU, and the permeation rate ratio of carbon dioxide and methane (R _CO2 / R _CH4 ) Is a gas separation membrane according to any one of [1] to [5].
[7]
The gas separation membrane according to any one of [1] to [6], wherein the support layer includes a porous layer on the gas separation layer side and a nonwoven fabric layer on the opposite side.
[8]
The gas separation membrane according to any one of [1] to [7], which is used to selectively permeate carbon dioxide from a gas containing carbon dioxide and methane.
[9]
A gas separation module comprising the gas separation membrane according to any one of [1] to [7].
[10]
A gas separation apparatus comprising the gas separation module according to [9].
[11]
The gas separation method which makes a carbon dioxide selectively permeate | transmit from the gas containing a carbon dioxide and methane using the gas separation membrane as described in any one of [1]-[8].

In the present specification, the numerical value range represented by “to” means that the numerical values described before and after it are included as the lower limit value and the upper limit value.
In the present specification, when there are a plurality of substituents, linking groups, and the like (hereinafter referred to as substituents) indicated by specific symbols, or when a plurality of substituents are specified simultaneously or alternatively, It means that a substituent etc. may mutually be same or different. The same applies to the definition of the number of substituents and the like. Further, when there are repetitions of a plurality of partial structures represented by the same indication in the formula, each partial structure or repeating unit may be the same or different.

In this specification, about the display of a compound thru | or group, it uses for the meaning containing those salts and those ions other than a compound thru | or group itself. In addition, it means that a part of the structure is changed as long as the desired effect is achieved.
In the present specification, a substituent that does not clearly indicate substitution or non-substitution (the same applies to a linking group) means that the group may have an arbitrary substituent as long as a desired effect is achieved. . This is also the same for compounds that do not specify substitution or non-substitution.
In the present specification, the substituent group Z is a preferred range unless otherwise specified.
The sulfonamido group herein, -S (= O) (= O) NR Q - or -S (= O) (= O ) N - - means a divalent group represented by. ^RQ represents a hydrogen atom or a substituent.

The gas separation membrane, the gas separation module, and the gas separation device of the present invention can achieve both gas permeability and plasticization resistance at a high level that is not on a conventional general trade-off line even when used under high pressure conditions. The gas separation can be realized with high speed, high selectivity and excellent plasticization resistance.
According to the gas separation method of the present invention, gas can be separated with excellent gas permeability and excellent gas separation selectivity even under high pressure conditions, and high speed and high selectivity gas separation is possible. And excellent plasticization resistance.

It is sectional drawing which shows typically one Embodiment of the gas separation composite membrane of this invention. It is sectional drawing which shows typically another embodiment of the gas separation composite membrane of this invention.

Hereinafter, preferred embodiments of the present invention will be described.
The gas separation membrane of the present invention contains a specific polymer compound (polysulfonamide compound) (hereinafter also referred to as a specific polymer compound) in the gas separation layer.

[Polymer compound]
The specific polymer compound used in the present invention contains a structural unit represented by the following formula (1) in the main chain. That is, in the specific polymer compound used in the present invention, a structural unit represented by the following formula (1) is incorporated in the main chain structure.
The structural unit represented by Formula (2) may be included in the main chain together with the structural unit represented by Formula (1).
Here, the proportion of the structural unit represented by the formula (2) contained in the polymer compound is preferably as small as possible, and the formula (2) with respect to 100 mol% of all the structural units contained in the polymer compound. It is more preferable that the proportion of the structural unit represented by) is 5 mol% or less.

In the above formulas (1) and (2), Z ^{1 to} Z ⁴ each independently represent a divalent linking group, for example, an arylene group (preferably a 1-5 cyclic arylene group, more preferably phenylene. Group, naphthylene group), alkylene group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and further preferably 1 to 6 carbon atoms), divalent saturated alicyclic hydrocarbon group (preferably carbon). 2 to 3 or more, more preferably 3 to 18 carbon atoms, still more preferably 4 to 8 carbon atoms, preferably a cyclohexyl group, a cyclopentyl group), an alkylene group, an arylene group, or two or more selected from these groups And a group formed by connecting groups with a single bond or a divalent group (preferably a group formed by connecting two or more arylene groups with a single bond or a divalent group). Two or more groups selected from the arylene group, alkylene group, and saturated alicyclic hydrocarbon group linked by the above divalent group, the substituents of these groups are linked to each other, You may form a ring with group. Examples of such a divalent group include an alkylene group (preferably a methylene group), an arylene group (preferably a phenylene group), and a saturated alicyclic hydrocarbon group (preferably a cyclohexyl group).
Z ^{1 to} Z ⁴ are preferably divalent groups including an arylene group, and more preferably, the above Z ^{1 to} Z ⁴ are each independently any one of the following formulas A-1 to A-11.

W ^{1 to} W ⁵⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a hydroxyl group or a carboxy group, preferably an alkyl group, a carboxy group or a hydrogen atom. Specific examples of the halogen atom, alkyl group, and alkoxy group that can be adopted by W ^{1 to} W ⁵⁰ include those exemplified in Substituent Group Z below.

Z ¹¹ represents _{^{-CR 8 2 -, - O -}} , - NR 8 -, - S- or a single bond, preferably -O - a -, - ^CR _{8 2.}

L ^{1 to} L ² each independently represent —CR ⁹ ₂ —, —O—, —NR ⁹ —, —S—, or a single bond, preferably —O— or —CR ⁸ ₂ —.

R ⁸ or R ⁹ represents a hydrogen atom, an alkyl group or an aryl group.
The alkyl group that can be adopted as R ⁸ or R ⁹ may be linear or branched, and may have a cyclic structure. Alkyl group which may take as R ⁸ or ^{R 9} is the number of carbon atoms thereof is preferably 1 to 20, more preferably 1 to 10, preferably 1 to 8 further more preferably more 1-6, particularly preferably 1-4 . Preferable specific examples of this alkyl group include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, s-butyl, isobutyl, cyclobutyl, n-hexyl and cyclohexyl. preferable. A halogen-substituted alkyl group is preferred. Preferable specific examples of the halogen-substituted alkyl group include, for example, a trifluoromethyl group.

R ⁸ or a carbon number of possible aryl group as ^{R 9} preferably 6 to 40, more preferably 6 to 30, more preferably 6 to 20, more preferably more 6 to 15, 6 to 12 are particularly preferred. Specific examples of the aryl group include phenyl, naphthyl, biphenyl, and terphenyl, and phenyl and biphenyl are particularly preferable. A halogen-substituted aryl group is preferred. Preferable specific examples of the halogen-substituted aryl group include trifluoromethyl.

Q ^{1, Q 2} are each independently, a sulfonamide group in a sulfonamido group (herein, -S (= O) (= O) NR Q - or -S (= O) (= O ) N - -. means a divalent group represented by .R ^Q is a divalent group containing a) represents a hydrogen atom or a substituent, for example, a sulfonamido group, respectively, an arylene group, an alkylene group or an alicyclic And divalent groups formed by combining groups selected from the formula hydrocarbon groups. In this divalent group, the connecting structure of the sulfonamide group and a group selected from an arylene group, an alkylene group or an alicyclic hydrocarbon group is preferably a single bond.

Y ¹ represents a hydrogen atom, an alkyl group, an aryl group, or any group of formulas (3) to (5).

R ^{3 to} R ⁶ each independently represents an alkyl group or an aryl group.
* 1 is a binding site with the nitrogen atom.

Examples of the alkyl group or aryl group that Y ¹ or R ^{3 to} R ⁶ can take include the above alkyl group or aryl group.

X ¹⁺ represents an organic or inorganic cation, and examples thereof include an ammonium cation and an alkali metal cation. Of these, organic cations are preferred.
n is an integer of 0 or more, preferably 0-2.

The polymer compound used in the present invention preferably contains a structural unit represented by the following formula (7) in the main chain.
A structural unit represented by the formula (8) may be included in the main chain together with the structural unit represented by the formula (7).
Here, the proportion of the structural unit represented by the formula (8) contained in the polymer compound is preferably small, and the formula (8) represents 100 mol% of all the structural units contained in the polymer compound. The proportion of the structural unit represented in the polymer compound is more preferably 5 mol% or less.

In the above formula (7) and formula (8), Z ^{5 to} Z ⁶ , Z ^{8 to} Z ⁹ , Y ^{2 to} Y ³ , X ^{2+ to} X ³⁺ are Z in the above formula (1) and formula (2). ¹ to Z ^4, a ^{Y 1,} synonymous with ^{X 1+.}

<Group represented by any one of formula (3) to formula (5)>
The specific polymer compound used in the present invention preferably contains a group represented by any ^one of formulas (3) to (5) as Y1. The groups represented by the formulas (3) to (5) are high in the monohydric acid anhydride or monovalent acid halide compound and the sulfonamide group incorporated in the main chain in the specific polymer compound. It can be formed by molecular reaction. The monovalent acid anhydride or monovalent acid halide compound means a monovalent compound that can react with the sulfonamide group in the specific polymer compound to form the group. Preferable examples of the monovalent acid anhydride or monovalent acid halide compound include carboxylic acid anhydride, sulfonic acid anhydride, carboxylic acid chloride, sulfonic acid chloride, and phosphoric acid chloride. Examples of the halide in the monovalent acid halide compound include chloride and bromide.
Specific examples of the monovalent acid anhydride and monovalent acid halide compound that can be used in the present invention are listed below, but the present invention is not limited thereto.
For example, the following H-1 and CL-1 can form the same group as Y ¹ even if the raw materials are different.

<Monovalent acid anhydride>

<Monovalent acid halide compound>

The structural unit constituting the polymer compound used in the present invention is a polysulfonamide compound having a sulfonamide group, which is a polar group, in the main chain of the polymer compound. It is considered that the gas selectivity and plasticization resistance were improved. When such a polymer compound is used in the gas separation layer, it is possible to achieve both excellent gas selectivity and plasticization resistance at a high level.
Moreover, by changing the aromatic units of Z ^{1 to} Z ⁶ , Z ^{8 to} Z ⁹ and Y ^{1 to} Y ³ , the balance of gas permeability, gas separation selectivity, and plasticization resistance can be adjusted well. It becomes possible.

The specific polymer compound used in the present invention is preferably synthesized from a diamine compound and a disulfonic acid halide compound.
The specific polymer compound used in the present invention is more preferably synthesized from the diamine compound exemplified below and the disulfonic acid halide compound exemplified below.
The specific polymer compound used in the present invention may have only one type of diamine compound and only one type of disulfonic acid halide compound, but two or more types of diamine compounds and two or more types of disulfonic acid halide compounds may be used. It is preferable to have.

  Examples of the diamine compound and disulfonic acid halide compound that can be suitably obtained for synthesizing the specific polymer compound are shown below.

<Disulfonic acid halide compound>

<Diamine compound>

  Examples of compounds suitable for synthesizing the specific polymer compound are shown below.

  The specific polymer compound used in the present invention is produced, for example, by a polycondensation reaction of a compound having two or more acid halide groups and a compound having two or more amino groups.

For example, according to the following two polymerization reactions, the same specific polymer compound (polysulfonamide compound) can be obtained. The molecular weight increases when the raw material diamine shown in the lower part is used.

  The specific polymer compound used in the present invention is more preferably produced by a sequential polymerization reaction of a compound having two or more acid halide groups and a diamine compound containing at least one sulfonamide group.

  The specific polymer compound used in the present invention is preferably a linear polymer compound.

Preferred specific examples of the specific polymer compound used in the present invention are shown in the following table. Exemplified compounds PS-1 to PS-25 mean polymer compounds obtained by reacting the diamine compounds described above and disulfonic acid halide compounds in the proportions (molar ratio) described in the table.
Moreover, the weight average molecular weight (Mw) of a polymer is the value measured by GPC method.
The specific polymer compound used in the present invention is not limited to the specific examples described in the following table.

The specific polymer compound of the present invention may contain other components (other structural units) as desired as long as the effects of the present invention are not impaired.
Hereinafter, the monovalent basic compound will be described.

<Monovalent basic compound>
The specific polymer compound of the present invention preferably contains a monovalent basic compound.
The monovalent basic compound used in the present invention means a monovalent basic compound capable of forming a salt structure with the sulfonamide group in the specific polymer compound. Preferred examples include alkali metal water. Oxides, oxides or bicarbonates, alkoxides (ROM), phenoxides (ArONa), etc., amines other than ammonia (gas or aqueous solution), diarylamines and triarylamines (diarylamines and triarylamines are almost Nearly neutral and excluded due to insufficient salt formation with acid groups), heterocyclic bases such as pyridine, quinoline, piperidine, hydrazine derivatives, amidine derivatives, tetraalkylammonium hydroxide, etc. Can do.
In the present invention, “forms a salt structure” means that a compound or group defined therein forms a salt as it is, and a part of the compound or salt is combined to form a salt. For example, the anion of a specific compound may dissociate and only the cation moiety may form a salt with a sulfonamide group. Further, the “salt structure” may be dissociated in the gas separation layer.
Among the monovalent basic compounds that can be used in the present invention, alkali metal hydroxides, oxides or bicarbonates, alkoxides (ROM), phenoxides (ArONa), ammonia (gas or aqueous solution). Preferred are nitrogen-containing compounds.
Specific examples of the monovalent basic compound that can be used in the present invention are listed below, but the present invention is not limited thereto.

Specific examples of the specific polymer compound suitable for the present invention having a salt structure formed of the specific polymer compound and a monovalent basic compound in the molecule are shown below.
The specific polymer compound used in the present invention is not limited to these specific examples.

Below, the specific example of the specific polymer compound suitable for this invention formed with the specific polymer compound and the acid anhydride or acid halide compound is shown.
The specific polymer compound used in the present invention is not limited to these specific examples.

Substituent group Z:
An alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, such as methyl, ethyl, iso-propyl, tert-butyl, n-octyl , N-decyl, n-hexadecyl, etc.), a cycloalkyl group (preferably a cycloalkyl group having 3 to 30 carbon atoms, more preferably 3 to 20 carbon atoms, particularly preferably 3 to 10 carbon atoms). For example, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably an alkenyl group having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, Vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 2 carbon atoms). 0, more preferably an alkynyl group having 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as propargyl and 3-pentynyl), an aryl group (preferably having 6 to 30 carbon atoms, and more). An aryl group having 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms is preferable, and examples thereof include phenyl, p-methylphenyl, naphthyl, anthranyl, and the like, amino groups (amino groups, alkylamino groups, An arylamino group and a heterocyclic amino group are included, preferably an amino group having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 10 carbon atoms, such as amino, methylamino, dimethylamino , Diethylamino, dibenzylamino, diphenylamino, ditolylamino, etc.), alkoxy group Preferably it is a C1-C30, More preferably, it is a C1-C20, Most preferably, it is a C1-C10 alkoxy group, for example, a methoxy, an ethoxy, butoxy, 2-ethylhexyloxy etc. are mentioned. An aryloxy group (preferably an aryloxy group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy, 2-naphthyloxy, etc. A heterocyclic oxy group (preferably a heterocyclic oxy group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as pyridyloxy, pyrazyloxy, Pyrimidyloxy, quinolyloxy, etc.),

  An acyl group (preferably an acyl group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, pivaloyl, etc.), alkoxy A carbonyl group (preferably an alkoxycarbonyl group having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl and ethoxycarbonyl), aryloxy A carbonyl group (preferably an aryloxycarbonyl group having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonyl), an acyloxy group ( Preferably 2-30 carbons, more preferably 2-20 carbons, especially preferred. Or an acyloxy group having 2 to 10 carbon atoms such as acetoxy and benzoyloxy), an acylamino group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably carbon number). 2-10 acylamino groups such as acetylamino and benzoylamino).

  An alkoxycarbonylamino group (preferably an alkoxycarbonylamino group having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino), aryl Oxycarbonylamino group (preferably an aryloxycarbonylamino group having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonylamino group). A sulfonylamino group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino and benzenesulfonylamino), a sulfamoyl group (Preferably 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably a sulfamoyl group having 0 to 12 carbon atoms, for example sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, and the like phenylsulfamoyl.),

  An alkylthio group (preferably an alkylthio group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio and ethylthio), an arylthio group (preferably An arylthio group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, and a heterocyclic thio group (preferably having 1 to 30 carbon atoms). More preferably a heterocyclic thio group having 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like. ),

  A sulfonyl group (preferably a sulfonyl group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as mesyl and tosyl), a sulfinyl group (preferably A sulfinyl group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, and the like, and a ureido group (preferably 1 carbon atom). -30, more preferably a ureido group having 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably having carbon number) 1 to 30, more preferably a phosphoric acid amide group having 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms. For example, diethyl phosphoric acid amide, phenylphosphoric acid amide, etc.), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom, more preferably fluorine atom). ),

A cyano group, a carboxy group, an oxo group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group (preferably a 3- to 7-membered heterocyclic group, neither an aromatic heterocyclic ring nor aromatic The hetero atom may be a hetero ring, and examples of the hetero atom constituting the hetero ring include a nitrogen atom, an oxygen atom and a sulfur atom, preferably 0 to 30 carbon atoms, more preferably a hetero ring having 1 to 12 carbon atoms. Specific examples include imidazolyl, pyridyl, quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl, azepinyl and the like, and a silyl group (preferably having a carbon number). A silyl group having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms. For example, trimethylsilyl, triphenylsilyl, etc.), a silyloxy group (preferably a silyloxy group having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms. , Triphenylsilyloxy, etc.). These substituents may be further substituted with any one or more substituents selected from the above substituent group Z.
In the present invention, when one structural site has a plurality of substituents, these substituents are connected to each other to form a ring, or condensed with a part or all of the above structural sites to form an aromatic group. A ring or an unsaturated heterocyclic ring may be formed.

When a compound or a substituent includes an alkyl group, an alkenyl group, etc., these may be linear or branched, and may be substituted or unsubstituted. When an aryl group, a heterocyclic group, or the like is included, they may be monocyclic or condensed, and may be substituted or unsubstituted.
In the present specification, what is merely described as a substituent refers to this substituent group Z unless otherwise specified, and when the name of each group is only described ( For example, when only “alkyl group” is described), preferred ranges and specific examples of the corresponding group in the substituent group Z are applied.

  The molecular weight of the polymer compound used in the present invention is preferably 10,000 to 1,000,000 as a weight average molecular weight, more preferably 15,000 to 500,000, still more preferably 20,000 to 200,000.

  In the present specification, unless otherwise specified, the molecular weight and the degree of dispersion are values measured using a GPC (gel filtration chromatography) method, and the molecular weight is a weight average molecular weight in terms of polystyrene. The gel packed in the column used in the GPC method is preferably a gel having an aromatic compound as a repeating unit, and examples thereof include a gel made of a styrene-divinylbenzene copolymer. It is preferable to use 2 to 6 columns connected together. Examples of the solvent used include ether solvents such as tetrahydrofuran and amide solvents such as N-methylpyrrolidinone. The measurement is preferably performed at a solvent flow rate in the range of 0.1 to 2 mL / min, and most preferably in the range of 0.5 to 1.5 mL / min. By performing the measurement within this range, the apparatus is not loaded and the measurement can be performed more efficiently. The measurement temperature is preferably 10 to 50 ° C, most preferably 20 to 40 ° C. Note that the column and carrier to be used can be appropriately selected according to the physical properties of the polymer compound that is symmetrical to the measurement.

[Synthesis of polymer compounds]
The polymer compound used in the present invention can be synthesized by condensation polymerization of a disulfonic acid halide compound and a diamine compound.

The polymer compound used in the present invention can be obtained by condensation polymerization using a method in which the above raw materials and a basic catalyst (for example, triethylamine, pyridine, etc.) are mixed in a solvent.
The solvent is not particularly limited, but ester organic solvents such as methyl acetate, ethyl acetate, and butyl acetate; aliphatics such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, cyclopentanone, and cyclohexanone. Ketone-based organic solvents, ether-based organic solvents such as ethylene glycol dimethyl ether, dibutyl ether, tetrahydrofuran, methylcyclopentyl ether, dioxane, and amide-based organic solvents such as N-methylpyrrolidone, 2-pyrrolidone, dimethylformamide, dimethylimidazolidinone, and dimethylacetamide Examples of the solvent include sulfur-containing organic solvents such as dimethyl sulfoxide and sulfolane. These organic solvents are appropriately selected as long as it is possible to dissolve the disulfonic acid halide compound and the diamine compound as the reaction substrate and the polymer compound as the final product. Preferably, ester type (preferably butyl acetate), aliphatic ketone type (preferably methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, cyclopentanone, cyclohexanone), ether type (diethylene glycol monomethyl ether, methyl cyclopentyl ether), amide A solvent of a system (preferably N-methylpyrrolidone) or a sulfur-containing system (dimethyl sulfoxide, sulfolane) is preferable. Moreover, these can be used combining 1 type (s) or 2 or more types of solvent.

  There is no restriction | limiting in particular in polymerization reaction temperature, The temperature normally employ | adopted in the synthesis | combination of a high molecular compound is employable. Specifically, it is preferably −50 to 250 ° C., more preferably −25 to 225 ° C., further preferably −10 ° C. to 100 ° C., and particularly preferably 0 ° C. to 70 ° C.

  In the present invention, the total concentration of the disulfonic acid halide compound and the diamine compound in the polymerization reaction solution of the polymer compound is not particularly limited, but is preferably 5 to 100% by mass, more preferably 20 to 90% by mass. Preferably, it is 30-60 mass% more preferably.

[Gas separation membrane]
[Gas separation composite membrane]
In the gas separation composite membrane which is a preferred embodiment of the gas separation membrane of the present invention, a gas separation layer containing a specific polymer compound is formed on the upper side of the gas permeable support layer. This composite membrane is applied to the above-mentioned coating solution (dope) forming the gas separation layer on at least the surface of the porous support (in this specification, coating is meant to include an aspect in which it is attached to the surface by dipping) )) Is preferable.
FIG. 1 is a longitudinal sectional view schematically showing a gas separation composite membrane 10 which is a preferred embodiment of the present invention. 1 is a gas separation layer, 2 is a support layer which consists of a porous layer. FIG. 2 is a cross-sectional view schematically showing a gas separation composite membrane 20 which is another preferred embodiment of the present invention. In this embodiment, a nonwoven fabric layer 3 is added as a support layer in addition to the gas separation layer 1 and the porous layer 2.
1 and 2 show an embodiment in which carbon dioxide is selectively permeated from a mixed gas of carbon dioxide and methane to make the permeated gas rich in carbon dioxide.

  In this specification, “upper support layer” means that another layer may be interposed between the support layer and the gas separation layer. As for the upper and lower expressions, unless otherwise specified, the side to which the gas to be separated is supplied is “upper”, and the side from which the separated gas is released is “lower”.

  In the gas separation composite membrane of the present invention, a gas separation layer may be formed and disposed on the surface or inner surface of a porous support (support layer). be able to. By forming a gas separation layer on at least the surface of the porous support, a composite membrane having the advantages of having both high separation selectivity, high gas permeability, and mechanical strength can be obtained. The thickness of the separation layer is preferably a thin film as much as possible under the condition of imparting high gas permeability while maintaining mechanical strength and separation selectivity.

  In the gas separation composite membrane of the present invention, the thickness of the gas separation layer is not particularly limited. The thickness of the gas separation layer is preferably 0.01 to 5.0 μm, and more preferably 0.05 to 2.0 μm.

The porous support (porous layer) preferably applied to the support layer is not particularly limited as long as it has the purpose of meeting mechanical strength and imparting high gas permeability. It may be a material. Preferably, it is an organic polymer porous film, and its thickness is 1 to 3000 μm, preferably 5 to 500 μm, and more preferably 5 to 150 μm. The pore structure of this porous membrane usually has an average pore diameter of 10 μm or less, preferably 0.5 μm or less, more preferably 0.2 μm or less. The porosity is preferably 20 to 90%, more preferably 30 to 80%.
Here, that the support layer has “gas permeability” means that carbon dioxide is supplied to the support layer (a film composed of only the support layer) at a temperature of 40 ° C. with a total pressure of 5 MPa on the gas supply side. It means that the permeation rate of carbon dioxide is 1 × 10 ⁻⁵ cm ³ (STP) / cm ² · sec · cmHg (10 GPU) or more. Further, the gas permeability of the support layer is such that when carbon dioxide is supplied at a temperature of 40 ° C. and the total pressure on the gas supply side is 5 MPa, the carbon dioxide transmission rate is 3 × 10 ⁻⁵ cm ³ (STP) / It is preferably cm ² · sec · cmHg (30 GPU) or more, more preferably 100 GPU or more, and further preferably 200 GPU or more. Examples of porous membrane materials include conventionally known polymers such as polyolefin resins such as polyethylene and polypropylene, fluorine-containing resins such as polytetrafluoroethylene, polyvinyl fluoride, and polyvinylidene fluoride, polystyrene, cellulose acetate, and polyurethane. And various resins such as polyacrylonitrile, polyphenylene oxide, polysulfone, polyethersulfone, polyimide, and polyaramid. The shape of the porous membrane may be any shape such as a flat plate shape, a spiral shape, a tubular shape, and a hollow fiber shape.

  In the gas separation composite membrane of the present invention, it is preferable that a support is formed to further impart mechanical strength to the lower portion of the support layer forming the gas separation layer. Examples of such a support include woven fabrics, nonwoven fabrics, nets, and the like, but nonwoven fabrics are preferably used in terms of film forming properties and cost. As the nonwoven fabric, fibers made of polyester, polypropylene, polyacrylonitrile, polyethylene, polyamide or the like may be used alone or in combination. The nonwoven fabric can be produced, for example, by making a main fiber and a binder fiber uniformly dispersed in water using a circular net or a long net, and drying with a dryer. Moreover, it is also preferable to apply a heat treatment by sandwiching a non-woven fabric between two rolls for the purpose of removing fluff and improving mechanical properties.

<Method for producing gas separation composite membrane>
The production method of the composite membrane of the present invention is preferably a production method including forming a gas separation layer by applying a coating liquid containing the polymer compound on a support. Although content of the high molecular compound in a coating liquid is not specifically limited, It is preferable that it is 0.1-30 mass%, and it is more preferable that it is 0.5-10 mass%. When the content of the polymer compound is too low, when the film is formed on the porous support, it easily penetrates into the lower layer, so that there is a high possibility that defects will occur in the surface layer that contributes to separation. On the other hand, if the content of the polymer compound is too high, the pores are filled at a high concentration when the film is formed on the porous support, and the permeability may be lowered. The gas separation membrane of the present invention can be appropriately produced by adjusting the molecular weight, structure, composition, and solution viscosity of the polymer in the separation layer.

  The organic solvent used as a medium for the coating solution is not particularly limited, but is a hydrocarbon organic solvent such as n-hexane or n-heptane, an ester organic solvent such as methyl acetate, ethyl acetate, or butyl acetate, Lower alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and tert-butanol, aliphatic ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, cyclopentanone and cyclohexanone, ethylene glycol , Diethylene glycol, triethylene glycol, glycerin, propylene glycol, ethylene glycol monomethyl or monoethyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, triplicate Ether-based organics such as pyrene glycol methyl ether, ethylene glycol phenyl ether, propylene glycol phenyl ether, diethylene glycol monomethyl or monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl or monoethyl ether, dibutyl ether, tetrahydrofuran, methylcyclopentyl ether, dioxane Examples include solvents, N-methylpyrrolidone, 2-pyrrolidone, dimethylformamide, dimethylimidazolidinone, dimethyl sulfoxide, dimethylacetamide and the like. These organic solvents are appropriately selected as long as they do not adversely affect the substrate. Preferably, ester type (preferably butyl acetate), alcohol type (preferably methanol, ethanol, isopropanol, isobutanol), aliphatic ketone (preferably methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, cyclopentanone, cyclohexanone) , Ether-based (ethylene glycol, diethylene glycol monomethyl ether, methylcyclopentyl ether) solvents are preferable, and aliphatic ketone-based, alcohol-based, and ether-based solvents are more preferable. Moreover, these can be used combining 1 type (s) or 2 or more types of solvent.

(Other layers between the support layer and the gas separation layer)
In the gas separation composite membrane of the present invention, another layer may exist between the support layer and the gas separation layer. A preferred example of the other layer is a siloxane compound layer. By providing the siloxane compound layer, the unevenness on the outermost surface of the support can be smoothed, and the separation layer can be easily thinned. Examples of the siloxane compound forming the siloxane compound layer include those having a main chain made of polysiloxane and compounds having a siloxane structure and a non-siloxane structure in the main chain.
In the present specification, the term “siloxane compound” means an organopolysiloxane compound unless otherwise specified.

-Siloxane compound whose main chain is made of polysiloxane-
Examples of the siloxane compound having a main chain made of polysiloxane that can be used in the siloxane compound layer include one or more polyorganosiloxanes represented by the following formula (1) or (2). Moreover, these polyorganosiloxanes may form a crosslinking reaction product. As the cross-linking reaction, for example, a compound represented by the following formula (1) is crosslinked by a polysiloxane compound having a group capable of linking by reacting with the reactive group X ^S of the formula (1) at both ends The compound of the form is mentioned.

In the formula (1), R ^S is a non-reactive group and is an alkyl group (preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms) or an aryl group (preferably having 6 to 6 carbon atoms). 15, more preferably an aryl group having 6 to 12 carbon atoms, still more preferably phenyl).
^XS is a reactive group, and is selected from a hydrogen atom, a halogen atom, a vinyl group, a hydroxy group, and a substituted alkyl group (preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms). It is preferably a group.
Y ^S and Z ^S are the above R ^S or X ^S.
m is a number of 1 or more, and preferably 1 to 100,000.
n is a number of 0 or more, preferably 0 to 100,000.

Wherein ^{(2), X S, Y} S, Z S, R S, m and n are ^X S of each formula ^{(1), Y S, Z} S, R S, and m and n synonymous.

In the above formulas (1) and (2), when the non-reactive group R ^S is an alkyl group, examples of the alkyl group include methyl, ethyl, hexyl, octyl, decyl, and octadecyl. . When the non-reactive group R is a fluoroalkyl group, examples of the fluoroalkyl group include —CH ₂ CH ₂ CF ₃ and —CH ₂ CH ₂ C ₆ F ₁₃ .

In the above formulas (1) and (2), when the reactive group ^XS is a substituted alkyl group, examples of the alkyl group include a hydroxyalkyl group having 1 to 18 carbon atoms and an aminoalkyl having 1 to 18 carbon atoms. Group, a carboxyalkyl group having 1 to 18 carbon atoms, a chloroalkyl group having 1 to 18 carbon atoms, a glycidoxyalkyl group having 1 to 18 carbon atoms, a glycidyl group, an epoxycyclohexylalkyl group having 7 to 16 carbon atoms, Examples thereof include (1-oxacyclobutan-3-yl) alkyl groups, methacryloxyalkyl groups, and mercaptoalkyl groups having 4 to 18 carbon atoms.
Preferably the number of carbon atoms of the alkyl group constituting the hydroxyalkyl groups is an integer of 1 to 10, for _example, -CH _{2 CH 2} CH ₂ OH.
Preferably the number of carbon atoms of the alkyl group constituting the amino alkyl group is an integer of 1 to 10, for _{example, -CH 2 CH 2 CH 2 NH 2} .
Preferably the number of carbon atoms of the alkyl group constituting the carboxyalkyl group is an integer of 1 to 10, for _example, -CH ₂ CH ₂ CH ₂ COOH.
The number of carbon atoms of the alkyl group constituting the chloroalkyl group is preferably an integer of 1 to 10, and a preferred example is —CH ₂ Cl.
The preferred carbon number of the alkyl group constituting the glycidoxyalkyl group is an integer of 1 to 10, and a preferred example is 3-glycidyloxypropyl.
The preferable carbon number of the said C7-C16 epoxy cyclohexyl alkyl group is an integer of 8-12.
A preferable carbon number of the (1-oxacyclobutan-3-yl) alkyl group having 4 to 18 carbon atoms is an integer of 4 to 10.
Preferred number of carbon atoms of the alkyl group constituting the methacryloxy group is an integer of 1 to 10, for _{example, -CH 2 CH 2 CH 2 -OOC} -C (CH 3) = CH 2 and the like.
The preferable carbon number of the alkyl group constituting the mercaptoalkyl group is an integer of 1 to 10, and examples thereof include —CH ₂ CH ₂ CH ₂ SH.
m and n are preferably numbers that give a molecular weight of 5,000 to 1,000,000.

In the above formulas (1) and (2), a reactive group-containing siloxane unit (wherein the number is a structural unit represented by n) and a siloxane unit having no reactive group (wherein the number is m The distribution of the structural unit represented by That is, in the formulas (1) and (2), the (Si (R ^S ) (R ^S ) —O) unit and the (Si (R ^S ) (X ^S ) —O) unit may be randomly distributed. .

-Compounds having siloxane structure and non-siloxane structure in the main chain-
Examples of the compound having a siloxane structure and a non-siloxane structure in the main chain that can be used in the siloxane compound layer include compounds represented by the following formulas (3) to (7).

Wherein ^{(3), R} S, m and n are respectively the same as ^R S, m and n in formula (1). R ^L is —O— or —CH ₂ —, and R ^S1 is a hydrogen atom or methyl. Both ends of the formula (3) are preferably an amino group, a hydroxyl group, a carboxy group, a trimethylsilyl group, an epoxy group, a vinyl group, a hydrogen atom, or a substituted alkyl group.

  In Formula (4), m and n are synonymous with m and n in Formula (1), respectively.

  In Formula (5), m and n are synonymous with m and n in Formula (1), respectively.

  In Formula (6), m and n are synonymous with m and n in Formula (1), respectively. It is preferable that the both ends of Formula (6) have an amino group, a hydroxyl group, a carboxy group, a trimethylsilyl group, an epoxy group, a vinyl group, a hydrogen atom, or a substituted alkyl group bonded thereto.

  In Formula (7), m and n are synonymous with m and n in Formula (1), respectively. It is preferable that an amino group, a hydroxyl group, a carboxy group, a trimethylsilyl group, an epoxy, a vinyl group, a hydrogen atom, or a substituted alkyl group is bonded to both ends of the formula (7).

  In the above formulas (3) to (7), the siloxane structural unit and the non-siloxane structural unit may be randomly distributed.

  The compound having a siloxane structure and a non-siloxane structure in the main chain preferably contains 50 mol% or more of siloxane structural units, more preferably 70 mol% or more, based on the total number of moles of all repeating structural units. .

  The weight average molecular weight of the siloxane compound used for the siloxane compound layer is preferably 5,000 to 1,000,000 from the viewpoint of achieving both thinning and durability. The method for measuring the weight average molecular weight is as described above.

Furthermore, the preferable example of the siloxane compound which comprises a siloxane compound layer is enumerated below.
Polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, polysulfone / polyhydroxystyrene / polydimethylsiloxane copolymer, dimethylsiloxane / methylvinylsiloxane copolymer, dimethylsiloxane / diphenylsiloxane / methylvinylsiloxane copolymer, methyl -3,3,3-trifluoropropylsiloxane / methylvinylsiloxane copolymer, dimethylsiloxane / methylphenylsiloxane / methylvinylsiloxane copolymer, diphenylsiloxane / dimethylsiloxane copolymer terminal vinyl, polydimethylsiloxane terminal vinyl, One or more selected from polydimethylsiloxane terminal H and dimethylsiloxane / methylhydrosiloxane copolymer. In addition, these include the form which forms the cross-linking reaction product.

In the composite film of the present invention, the thickness of the siloxane compound layer is preferably 0.01 to 5 μm, and more preferably 0.05 to 1 μm, from the viewpoint of smoothness and gas permeability.
Further, the gas permeability at 40 ° C. and 4 MPa of the siloxane compound layer is preferably 100 GPU or more, more preferably 300 GPU or more, and further preferably 1000 GPU or more in terms of carbon dioxide transmission rate.

[Gas separation asymmetric membrane]
The gas separation membrane of the present invention may be an asymmetric membrane. The asymmetric membrane can be formed by a phase change method using a solution containing a polyimide compound. The phase inversion method is a known method for forming a film while bringing a polymer solution into contact with a coagulation liquid to cause phase conversion. In the present invention, a so-called dry / wet method is suitably used. The dry and wet method evaporates the solution on the surface of the polymer solution in the form of a film to form a thin dense layer, and then immerses it in a coagulation liquid (solvent that is compatible with the solvent of the polymer solution and the polymer is insoluble), This is a method of forming a porous layer by forming micropores using the phase separation phenomenon that occurs at that time, and proposed by Rob Thrillerjan et al. (For example, US Pat. No. 3,133,132) It is.

  In the gas separation asymmetric membrane of the present invention, the thickness of the surface layer that contributes to gas separation called a dense layer or a skin layer is not particularly limited. The thickness of the surface layer is preferably 0.01 to 5.0 μm, more preferably 0.05 to 1.0 μm, from the viewpoint of imparting practical gas permeability. On the other hand, the porous layer below the dense layer lowers the gas permeability resistance and at the same time plays a role of imparting mechanical strength, and its thickness is particularly limited as long as it is self-supporting as an asymmetric membrane. It is not limited. This thickness is preferably 5 to 500 μm, more preferably 5 to 200 μm, and still more preferably 5 to 100 μm.

  The gas separation asymmetric membrane of the present invention may be a flat membrane or a hollow fiber membrane. The asymmetric hollow fiber membrane can be produced by a dry and wet spinning method. The dry-wet spinning method is a method for producing an asymmetric hollow fiber membrane by applying a dry-wet method to a polymer solution that is discharged from a spinning nozzle to have a hollow fiber-shaped target shape. More specifically, the polymer solution is discharged from a nozzle into a hollow fiber-shaped target shape, and after passing through an air or nitrogen gas atmosphere immediately after discharge, the polymer is not substantially dissolved and is compatible with the solvent of the polymer solution. In this method, an asymmetric structure is formed by immersing in a coagulating liquid containing, then dried, and further heat-treated as necessary to produce a separation membrane.

  The solution viscosity of the solution containing the polyimide compound discharged from the nozzle is 2 to 17000 Pa · s, preferably 10 to 1500 Pa · s, particularly preferably 20 to 1000 Pa · s at the discharge temperature (for example, 10 ° C.). It is preferable because a shape after discharge such as a thread shape can be stably obtained. For immersion in the coagulation liquid, the film is immersed in the primary coagulation liquid and solidified to such an extent that the shape of the hollow fiber or the like can be maintained, wound on a guide roll, and then immersed in the secondary coagulation liquid to fully saturate the entire film. It is preferable to solidify. It is efficient to dry the coagulated film after replacing the coagulating liquid with a solvent such as hydrocarbon. The heat treatment for drying is preferably performed at a temperature lower than the softening point or secondary transition point of the used polyimide compound.

  In the gas separation membrane of the present invention, a siloxane compound layer may be provided on the gas separation layer as a protective layer in contact with the gas separation layer.

[Uses and characteristics of gas separation membranes]
The gas separation membrane (composite membrane and asymmetric membrane) of the present invention can be suitably used as a gas separation recovery method and gas separation purification method. For example, hydrogen, helium, carbon monoxide, carbon dioxide, hydrogen sulfide, oxygen, nitrogen, ammonia, sulfur oxides, nitrogen oxides, hydrocarbons such as methane and ethane, unsaturated hydrocarbons such as propylene, tetrafluoroethane, etc. A gas separation membrane capable of efficiently separating a specific gas from a gas mixture containing a gas such as a perfluoro compound. In particular, a gas separation membrane that selectively separates carbon dioxide from a gas mixture containing carbon dioxide / hydrocarbon (methane) is preferable.

In particular, when the gas to be separated is a mixed gas of carbon dioxide and methane, the permeation rate of carbon dioxide at 40 ° C. and 5 MPa is preferably more than 20 GPU, more preferably more than 30 GPU, More preferably, it is 35 to 500 GPU. The permeation rate ratio between carbon dioxide and methane (R _CO2 / R _CH4 ) is preferably 15 or more, and more preferably 20 or more. R _CO2 represents the permeation rate of carbon dioxide, and R _CH4 represents the permeation rate of methane.
1 GPU is 1 × 10 ⁻⁶ cm ³ (STP) / cm ² · sec · cmHg.

[Other ingredients]
Various polymer compounds can be added to the gas separation layer of the gas separation membrane of the present invention in order to adjust the membrane properties. High molecular compounds include acrylic polymers, polyurethane resins, polyamide resins, polyester resins, epoxy resins, phenol resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl formal resins, shellac, vinyl resins, acrylic resins, rubber resins. Waxes and other natural resins can be used. Two or more of these may be used in combination.
In addition, a nonionic surfactant, a cationic surfactant, and / or an organic fluoro compound can be added to adjust liquid properties.

  Specific examples of the surfactant include alkylbenzene sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfonate of higher fatty acid ester, sulfate ester of higher alcohol ether, sulfonate of higher alcohol ether, higher alkyl Anionic surfactants such as alkyl carboxylates of sulfonamides, alkyl phosphates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, ethylene oxide adducts of acetylene glycol, Nonionic surfactants such as ethylene oxide adducts of glycerin and polyoxyethylene sorbitan fatty acid esters, as well as amphoteric boundaries such as alkylbetaines and amidebetaines Active agents, silicone surface active agents, including such fluorine-based surfactant, can be appropriately selected from surfactants and derivatives thereof are known.

  In addition, a polymer dispersant may be included, and specific examples of the polymer dispersant include polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, polyethylene glycol, polypropylene glycol, and polyacrylamide. Of these, polyvinylpyrrolidone is preferably used.

  Although there is no restriction | limiting in particular in the conditions which form the gas separation membrane of this invention, -30-100 degreeC is preferable, as for temperature, -10-80 degreeC is more preferable, and 5-50 degreeC is especially preferable.

In the present invention, a gas such as air or oxygen may coexist at the time of forming the film, but it is preferably in an inert gas atmosphere.
In the gas separation membrane of the present invention, the content of the polymer compound in the gas separation layer is not particularly limited as long as desired gas separation performance can be obtained. From the viewpoint of further improving the gas separation performance, the content of the polymer compound in the gas separation layer is preferably 20% by mass or more, more preferably 40% by mass or more, and 60% by mass or more. Is more preferable, and it is especially preferable that it is 70 mass% or more. Further, the content of the polymer compound in the gas separation layer may be 100% by mass, but is usually 99% by mass or less.

[Separation method of gas mixture]
The gas separation method of the present invention is a method for separating a specific gas from a mixed gas of two or more components using the gas separation membrane of the present invention. The gas separation method of the present invention is a method including selectively permeating carbon dioxide from a mixed gas containing carbon dioxide and methane. The pressure during gas separation is preferably 0.5 to 10 MPa, more preferably 1 to 10 MPa, and further preferably 2 to 7 MPa. The gas separation temperature is preferably −30 to 90 ° C., more preferably 15 to 70 ° C. In the mixed gas containing carbon dioxide and methane gas, the mixing ratio of carbon dioxide and methane gas is not particularly limited, but is preferably carbon dioxide: methane gas = 1: 99 to 99: 1 (volume ratio). Methane gas is more preferably 5:95 to 90:10.

[Gas separation module or gas separation device]
A gas separation membrane module can be prepared using the gas separation membrane of the present invention. Examples of modules include spiral type, hollow fiber type, pleated type, tubular type, plate & frame type and the like.
In addition, a gas separation apparatus having means for separating and recovering or purifying gas can be obtained using the gas separation composite membrane or gas separation membrane module of the present invention. The gas separation composite membrane of the present invention may be applied to, for example, a membrane used in combination with an absorbing solution as described in JP 2007-297605 A and / or a gas separation and recovery device as an absorption hybrid method.

  The present invention will be described below in more detail based on examples, but the present invention is not limited to these examples. In this example, “parts” and “%” mean “parts by mass” and “mass%” unless otherwise specified.

(Synthesis example)
<Synthesis of sulfonamide-containing diamine (SA-1)>
In a 1 L three-necked flask equipped with a condenser and a stirrer, 280.0 g of chlorosulfonic acid was weighed, then cooled to 0 ° C., and 64.91 g of 1,3-diisopropylbenzene (manufactured by Wako Pure Chemical Industries, Ltd.) The solution was added dropwise over time and stirred at room temperature for 1 hour. The reaction was warmed to 55 ° C. and stirred for 3 hours. The reaction solution was cooled to room temperature while stirring, crystallized in 2 L of ice-cold water, stirred for 30 minutes, and then collected by filtration and dissolved in 1 L of ethyl acetate. This ethyl acetate solution was transferred to a separating funnel, and separated and washed twice with pure water, and then separated and washed with saturated saline. The organic layer was transferred to an Erlenmeyer flask, 30 g of magnesium sulfate was added and stirred, and the solid matter was removed by filtration. Then, ethyl acetate was distilled off using an evaporator and dried in vacuo at 40 ° C. for 24 hours. 87.0g of precursor S-1 (disulfonic acid chloride body) was obtained. The precursor (S-1) was confirmed from the NMR spectrum.

In a 2 L three-necked flask equipped with a condenser and a stirrer, 45.1 g of 2,4,6-trimethyl-1,3-phenylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 200 g of acetonitrile were weighed, and 0 to 5 ° C. The mixture was stirred while cooling. After 18.0 g of the precursor (S-1) obtained above was dissolved in 200 g of tetrahydrofuran, it was transferred to a dropping funnel, dropped into the stirring three-necked flask over 1 hour, and stirred for 1 hour. The reaction solution was returned to room temperature and stirred for 2 hours, and then 200 g of 1M sodium hydroxide aqueous solution and 300 g of pure water were added and stirred. The crystal was vacuum-dried at 40 ° C. for 24 hours to obtain 21.1 g of the desired product (SA-1). The desired product was confirmed from the NMR spectrum.
Similarly, SA-2 to SA-100 can be synthesized.

<Synthesis Example of Polysulfonamide Compound (PS-1)>
A three-necked flask equipped with a condenser and a stirrer was weighed 20.538 g of SA-1 obtained by the same method as the above synthesis method, 40.60 g of dehydrated N-methylpyrrolidone, and 6.92 g of dehydrated pyridine. And stirred with ice cooling to obtain a homogeneous solution. Next, 11.102 g of 2,4,6-mesitylene disulfonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, stirred at 0-10 ° C. for 1 hour, reacted at 60 ° C. for 3 hours, and returned to room temperature. Next, 50.0 g of N-methylpyrrolidone was added to this three-necked flask and dissolved. The reaction solution was poured into a mixed solution of 1 L of methanol and 1 L of 1N hydrochloric acid water to precipitate a polymer. This was collected by filtration, washed and dried to obtain 28.2 g of a polysulfonamide compound (binder polymer) (PS-1) having a weight average molecular weight of 72,000. It was confirmed from the NMR spectrum, IR spectrum, and GPC (polystyrene conversion) that it was the target product.
PS-2 to PS-25 can be synthesized by the same method.

<Synthesis Example of Polysulfonamide Compound (PSC-1)>
In a 100 mL three-necked flask equipped with a condenser and a stirrer, 3.00 g of polyimide resin PS-13 obtained by the above synthesis method and 27.0 g of N-methylpyrrolidone were weighed and stirred at room temperature to obtain a uniform solution. . 3.00 g of pyridine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1.96 g of acetic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, stirred at room temperature for 1 hour, and reacted at 80 ° C. for 3 hours. Next, 10 g of N-methylpyrrolidone was added and dissolved. This reaction solution was poured into a mixed solution of 0.2 L of methanol and 0.2 L of 1N hydrochloric acid to precipitate a polysulfonamide compound. This was collected by filtration, washed and dried to obtain 2.5 g of a polysulfonamide compound (binder polymer) (PIC-1) having a weight average molecular weight of 65,000. It was confirmed from the NMR spectrum, IR spectrum, and GPC (polystyrene conversion) that it was the target product.
Note that PSC-2 to PSC-11 can be synthesized by the same method.

  In the examples, “weight average molecular weight” was calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC). However, a GPC column packed with polystyrene cross-linked gel (TSKgel SuperAWM-H; manufactured by Tosoh Corporation) and N-methylpyrrolidone (phosphoric acid and lithium bromide 0.01 mol / L each) were used as a GPC solvent.

<Synthesis Example of Polyimide Compound (PSB-1)>
In a 200 ml three-necked flask, 95 g of N-methyl-2-pyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.) was weighed, then 5 g of polysulfonamide (PS-1) was added and dissolved while stirring. Next, 0.054 g of triethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was weighed, added, and stirred at room temperature for 1 hour. The reaction solution was poured into 0.5 L of methanol and 0.5 L of pure water to precipitate a polymer. This was filtered, washed and dried to obtain 4.6 g of a polysulfonamide compound (binder polymer) (PSB-1) having a weight average molecular weight of 78000. It was confirmed from the NMR spectrum, IR spectrum, and GPC (polystyrene conversion) that it was the target product.

Example 1
<Production of composite membrane>
A gas separation composite membrane shown in FIG. 2 was produced.
In a 30 ml brown vial, 1.4 g of polysulfonamide compound (PIC-1) and 8.6 g of tetrahydrofuran were mixed and stirred for 30 minutes, and further 1-hydroxycyclohexyl phenyl ketone (manufactured by Aldrich, product number: 40, 281-2 of 561-2) was added, and the mixture was further stirred for 30 minutes. A polyacrylonitrile porous membrane (manufactured by GMT) is allowed to stand on a 10 cm square clean glass plate, and the polysulfonamide compound (PIC-1) solution is cast on the porous support membrane surface using an applicator, A composite membrane (Example 1) was obtained. The thickness of the polysulfonamide compound (PIC-1) layer was about 1 μm, and the thickness of the polyacrylonitrile porous film including the nonwoven fabric was about 180 μm.
These polyacrylonitrile porous membranes had a molecular weight cut-off of 100,000 or less.

Examples 2-8
<Production of other composite films>
In the said Example 1, the composite film of Examples 2-8 shown in Table 1 was produced by changing a polysulfonamide compound (PIC-1) as shown in Table 1.

Comparative Examples 1-2
<Production of composite membrane>
In the said Example 1, the composite film of Comparative Examples 1-2 shown in Table 1 is produced by changing a polysulfonamide compound (PIC-1) into the comparative polymers C-1 and C-2 of Table 1. did.
Comparative polymers C-1 and C-2 used in Comparative Examples 1 and 2 are shown below.

<Evaluation of gas separation performance>
For each of the obtained composite membranes, a volume ratio of carbon dioxide (CO ₂ ) and methane (CH ₄ ) is 1: 1 using a stainless steel cell made of SUS316 (DENISSEN) having high pressure resistance. Using a mass flow controller, the permeability of each gas of CO ₂ and CH ₄ is TCD detection type gas chromatograph at 40 ° C. and the total pressure on the gas supply side is 5 MPa (CO ₂ and CH ₄ partial pressure: 2.5 MPa). Measured graphically. The gas permeability of each composite membrane was compared by calculating the gas permeability (Permeance). The unit of gas permeability was expressed in GPU (GPU) units (1 GPU = 1 × 10 ⁻⁶ cm ³ (STP) / (s · cm ² · cmHg)).
A carbon dioxide / methane permeation ratio of 30 or more was evaluated as A, 20 or more and less than 30 as evaluation B, 10 or more and less than 20 as evaluation C, and 0 or more and less than 10 as evaluation D.
Gas permeability of 80 GPU or more was evaluated as A, 50 GPU or more and less than 80 GPU as evaluation B, 20 or more and less than 50 as evaluation C, and less than 20 GPU as evaluation D.

<Toluene exposure test>
Create a bulk sample of about 150-180 mg (1 mass% solution is dried overnight), then age at 90 ° C. for 1 week (1 wk), leave it at 25 ° C. and 20% RH for more than half a day, Measure the mass. Store in a toluene atmosphere container in a vapor-liquid equilibrium state, measure the mass after 7 days, and determine the mass change (mass after 7 days / initial mass). Furthermore, toluene swelling rate was calculated | required from the following formula.

Toluene swelling ratio = [(mass after 7 days−initial mass) / initial mass] × 100

The toluene swelling rate was less than 10% as evaluation A, 10% or more and less than 25% as evaluation B, 25% or more and less than 40% as evaluation C, and toluene swelling rate as 40% or more as evaluation D.
The above measurement results are shown in Table 4.

As shown in Table 4 above, the gas separation membrane of the comparative example using the comparative polymer (C-1 or C-2) has gas permeability, carbon dioxide and methane selectivity, and toluene swelling (plasticization resistance). (Comparative Examples 1 and 2).
On the other hand, the gas separation membrane containing the polymer compound containing the structural unit represented by the formula (1) of the present invention has gas permeability, selectivity of carbon dioxide and methane, and toluene swelling (plasticization resistance). (Examples 1 to 8).

  From the above results, it was found that when the gas separation membrane of the present invention is used, an excellent gas separation method, a gas separation module, and a gas separation apparatus equipped with this gas separation module can be provided.

DESCRIPTION OF SYMBOLS 1 Gas separation layer 2 Porous layer 3 Nonwoven fabric layer 10, 20 Gas separation composite membrane

Claims (11)

A gas separation membrane having a gas separation layer containing a polymer compound, wherein the polymer compound has a structural unit represented by the following formula (1) in the main chain.

In formula (1), Z ¹ and Z ² each independently represent a divalent linking group, Q ¹ represents a divalent group containing a sulfonamide group, Y ¹ represents a hydrogen atom, an alkyl group, an aryl group or The group in any one of Formula (3)-Formula (5) is shown, and n is an integer greater than or equal to 0.

In formula (3) to formula (5), R ^{3 to} R ⁶ each independently represents an alkyl group or an aryl group. * 1 is a binding site with the nitrogen atom. The gas separation membrane according to claim 1, wherein a part or all of the structural unit represented by the formula (1) constituting the polymer compound is a structural unit represented by the following formula (7).

In Formula (7), Z ^{5 to} Z ⁶ each independently represent a divalent linking group, and Y ² and Y ³ are each independently a hydrogen atom, an alkyl group, an aryl group, or Formula (3) to Formula (5). Any one of these groups is shown.

In formula (3) to formula (5), R ^{3 to} R ⁶ each independently represents an alkyl group or an aryl group. * 1 is a binding site with the nitrogen atom. Z ^{1 to} Z ² and Z ^{5 to} Z ⁶ are each independently a divalent group containing an arylene group.
The gas separation membrane according to claim 1 or 2. The gas separation membrane according to claim 1 or 2, wherein Z ^{1 to} Z ² and Z ^{5 to} Z ⁶ are each independently any of the following formulas A-1 to A-11.

In the formula, each of W ^{1 to} W ⁵⁰ independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a hydroxyl group, or a carboxy group, and Z ¹¹ represents —CR ⁸ ₂ —, —O—, —NR ⁸ —, indicates -S- or a single ^bond, the L 1 ~L ² are each _{^{independently, -CR 9 2 -, - O}} -, - NR 9 -, - S- or a single bond. R ⁸ represents a hydrogen atom, an alkyl group or an aryl group. R ⁹ represents a hydrogen atom, an alkyl group or an aryl group.   The gas separation membrane according to any one of claims 1 to 4, wherein the gas separation membrane is a gas separation composite membrane having the gas separation layer on the gas permeable support layer. In the case where the gas to be separated is a mixed gas of carbon dioxide and methane, the permeation rate of carbon dioxide at 40 ° C. and 5 MPa exceeds 20 GPU, and the permeation rate ratio of carbon dioxide and methane (R _CO2 / R _CH4 ) The gas separation membrane according to any one of claims 1 to 5, wherein is 15 or more.   The gas separation membrane according to any one of claims 1 to 6, wherein the support layer comprises a porous layer on the gas separation layer side and a nonwoven fabric layer on the opposite side.   The gas separation membrane according to any one of claims 1 to 7, which is used for selectively transmitting carbon dioxide from a gas containing carbon dioxide and methane.   A gas separation module comprising the gas separation membrane according to claim 1.   A gas separation apparatus comprising the gas separation module according to claim 9.   A gas separation method in which carbon dioxide is selectively permeated from a gas containing carbon dioxide and methane using the gas separation membrane according to claim 1.

Images