JP5404228B2 - Carbon membrane and gas separation method using the same - Google Patents

Description

  The present invention relates to a novel carbon membrane obtained by thermally decomposing a membrane made of an aromatic polyether having a proton acid group, and a gas separation method using the carbon membrane.

  The separation of a specific gas from a mixed gas has been conventionally performed by a cryogenic separation method, an adsorption separation method (PSA), and a chemical / physical absorption method. However, since these techniques require a cryogenic state, a high pressure state, or a regeneration operation of the absorbing solution for separation, enormous energy is required to implement these techniques.

  On the other hand, polyimide, polyaramid, polyamide, polyethersulfone, silicon, silicon carbide, silicon nitride, polypropylene, polyethylene, polycarbonate, palladium-based oxides such as silica, alumina, titania, zirconia, and complex oxides thereof, zeolite, etc. The gas separation technology using a polymer separation membrane has advantages such as low energy, miniaturization of the apparatus, and easy maintenance of the apparatus. Therefore, the technologies include hydrogen recovery from various processes in petroleum refining, water removal in oil, adjustment of hydrogen / carbon monoxide ratio in various reaction processes in the chemical industry, hydrogen recovery, production of high purity hydrogen, natural gas and land It has been applied to carbon dioxide separation from fill gas, helium recovery from natural gas, acid gas removal, and the like. Landfill gas refers to gas generated from the landfill of waste, and about 40% of the gas is composed of methane.

  However, the separation of the gaseous object by the polymer separation membrane is greatly influenced by the permeation rate of each component present in the gas. Therefore, when trying to separate a gas containing many trace impurities such as coke oven gas and coal gasification gas with a polymer separation membrane, performance such as separation and recovery rate of gaseous objects in the polymer separation membrane The decline is severe. Although studies have been made to prevent this performance degradation, it has not been put into practical use industrially.

  Carbon molecular sieve membrane (CMSM) is a material with excellent heat resistance and chemical resistance, and has high separation performance and gas transport characteristics for mixed gas through a molecular sieve mechanism. Over the years, CMSM having gas separation characteristics has been produced by changing the pyrolysis temperature and time of the polymer that becomes CMSM (see Non-Patent Documents 1 and 2).

  CMSM has both micropores (<7 ＜) and micropores. Ultra micropores are mainly involved in molecular sieving, and micropores have little resistance to gas diffusion and have a high gas adsorption capacity. However, no CMSM that can achieve both gas separation characteristics and transport characteristics at a high level has been provided.

C. W. Jones, W. J. Koros, Carbon molecular sieve gas separation membranes-II.Regeneration following organic exposure, Carbon 32 (1994) 1427-1432 K. M. Steel, W. J. Koros, Investigation of porosity of carbon materials and related effects on gas separation properties, Carbon 41 (2003) 253-266

  An object of the present invention is to provide a novel carbon membrane having excellent gas separation performance and a gas separation method using the carbon membrane.

  As a result of intensive investigations to achieve the above object, the present inventors have obtained a novel carbon membrane obtained by pyrolyzing a membrane comprising a novel aromatic polyether having a proton acid group. As a result, the present invention was completed.

That is, the present invention relates to a carbon membrane shown in the following [1] to [11] and a gas separation method using the carbon membrane.
[1] A carbon film obtained by thermally decomposing a film made of an aromatic polyether having a proton acid group.

  [2] The carbon film according to [1], wherein the aromatic polyether is an aromatic polyether having a repeating structural unit represented by the following general formula (1):

［式（１）中、各Ｘはそれぞれ独立にＨ、プロトン酸基、−Ｃ_mＨ_2m+1（ｍは１〜１０の整数），−Ｃｌ，−Ｆ，−ＣＦ₃または−ＣＮであり、
複数存在するＸのうち少なくとも一つはプロトン酸基であり、
Ａ¹およびＡ²はそれぞれ独立して直接結合，−ＣＨ₂−，−Ｃ（Ｃ_pＨ_2p+1）₂−（ｐは１〜１０の整数），−Ｃ（ＣＦ₃）₂−，−Ｏ−，−ＳＯ₂−または−ＣＯ−であり、
ｊ，ｋ，ｌはそれぞれ独立して０または１を示す。］。

In Expression (1), each X is independently H, protonic acid _{group, -C m H 2m + 1 (} m is an integer of from 1 to 10), - Cl, -F, be -CF ₃ or -CN ,
At least one of the plurality of X is a protonic acid group,
A ¹ and A ² are each independently a direct bond, —CH ₂ —, —C (C _p H _{2p + 1} ) ₂ — (p is an integer of 1 to 10), —C (CF ₃ ) ₂ —, — O—, —SO ₂ — or —CO—,
j, k, and l each independently represent 0 or 1. ].

  [3] The carbon film according to [1] or [2], wherein the aromatic polyether is an aromatic polyether having a repeating structural unit represented by the following general formula (2):

［式（２）中、各Ｘはそれぞれ独立にＨ、プロトン酸基、−Ｃ_mＨ_2m+1（ｍは１〜１０の整数），−Ｃｌ，−Ｆ，−ＣＦ₃または−ＣＮであり、
複数存在するＸのうち少なくとも一つはプロトン酸基であり、
Ａ¹は−ＳＯ₂−または−ＣＯ−であり、
Ａ²は直接結合，−ＣＨ₂−，−Ｃ（Ｃ_pＨ_2p+1）₂−（ｐは１〜１０の整数），−Ｃ（ＣＦ₃）₂−，−Ｏ−，−ＳＯ₂−または−ＣＯ−であり、
ｋ，ｌはそれぞれ独立して０または１を示す。］。

[In the formula (2), each X is independently H, protonic acid _{group, -C m H 2m + 1 (} m is an integer of from 1 to 10), - Cl, -F, be -CF ₃ or -CN ,
At least one of the plurality of X is a protonic acid group,
A ¹ is —SO ₂ — or —CO—.
A ² is a direct bond, —CH ₂ —, —C (C _p H _{2p + 1} ) ₂ — (p is an integer of 1 to 10), —C (CF ₃ ) ₂ —, —O—, —SO ₂ —. Or -CO-
k and l each independently represent 0 or 1. ].

[4] The protonic acid group is —C _n H _2n —SO ₃ Y (n is an integer of 0 to 10, and Y is H, Na, K or Ag). The carbon film according to any one of [1] to [3].

  [5] The aromatic polyether is a copolymer composed of repeating structural units represented by the following formulas (3) and (4), according to any one of [1] to [4] Carbon film:

［式（３）および（４）中、Ｒ₁〜Ｒ₆はそれぞれ独立に水素または−Ｃ_mＨ_2m+1（ｍは１〜８の整数）であり、
２つ存在するＹは独立にＮａ，Ｋ，ＨまたはＡｇであり、
式（３）で表わされる繰り返し構造単位の共重合比率（モル比）をｗ、式（４）で表わされる繰り返し構造単位の共重合比率をｚとすると（ただしｗ＋ｚ＝１）、０．２≦ｗ≦０．８かつ０．８≧ｚ≧０．２である。］。

[In the formulas (3) and (4), R _{1 to} R ₆ are each independently hydrogen or —C _m H _{2m + 1} (m is an integer of 1 to 8),
The two Ys are independently Na, K, H or Ag;
When the copolymerization ratio (molar ratio) of the repeating structural unit represented by the formula (3) is w and the copolymerization ratio of the repeating structural unit represented by the formula (4) is z (where w + z = 1), 0.2 ≦ w ≦ 0.8 and 0.8 ≧ z ≧ 0.2. ].

  [6] Any one of [1] to [5], wherein the aromatic polyether is a copolymer composed of repeating structural units represented by the following formulas (5) and (6): Carbon film:

［式（５）中、２つ存在するＹは独立にＮａ，Ｋ，ＨまたはＡｇであり、
式（５）で表わされる繰り返し構造単位の共重合比率（モル比）をｓ、式（６）で表わされる繰り返し構造単位の共重合比率をｔとすると（ただしｓ＋ｔ＝１）、０．２≦ｓ≦０．８かつ０．８≧ｔ≧０．２である。］。

[In Formula (5), two Ys are independently Na, K, H or Ag;
When the copolymerization ratio (molar ratio) of the repeating structural unit represented by the formula (5) is s and the copolymerization ratio of the repeating structural unit represented by the formula (6) is t (where s + t = 1), 0.2 ≦ s ≦ 0.8 and 0.8 ≧ t ≧ 0.2. ].

[7] The carbon film according to [5], wherein in the general formula (3), Y is Ag.
[8] The carbon film according to [6], wherein in the general formula (5), Y is Ag.

[9] The carbon film according to any one of [1] to [8], wherein a maximum temperature of heating in the pyrolysis is 500 to 1000 ° C.
[10] The carbon film according to any one of [1] to [9], having a thickness of 20 to 100 μm.

  [11] A method of separating at least one gas or vapor from the mixture by bringing the gas mixture or vapor mixture into contact with the carbon membrane according to any one of [1] to [10] under pressure.

  According to the present invention, a novel carbon membrane having excellent gas separation performance and a gas separation method using the carbon membrane are provided.

The present invention is described in detail below.
The carbon membrane according to the present invention is a robust carbon membrane having high separation and transport performance in the separation of mixed gas. Such a carbon film can be obtained by thermally decomposing a film made of an aromatic polyether having a proton acid group (hereinafter also referred to as “proton acid group-containing aromatic polyether”). In particular, when the proton acid group is a sulfonic acid group, good gas separation and transport characteristics can be obtained.

[Membrane made of aromatic acid group-containing aromatic polyether]
The film used as the raw material of the carbon film according to the present invention is made of a protonic acid group-containing aromatic polyether.

<Protonic acid group-containing aromatic polyether>
From the membrane composed of the protonic acid group-containing aromatic polyether, holes for gas separation of hydrogen, nitrogen, methane, carbon dioxide and the like are formed by thermal decomposition.

Specific examples of the protonic acid group include sulfonic acid groups, carboxylic acid groups, and phosphonic acid groups represented by the following formulas (A) to (C). Among these, since excellent gas separation performance is achieved, a sulfonic acid group represented by the following formula (A) is preferable, and a sulfonic acid group when n = 0 in the following formula (A) is particularly preferable.
_{(A) -C n H 2n -SO} 3 Y (n is an integer of 0, Y is H, Na, K, or Ag)
(B) —C _n H _2n —COOY (n is an integer of 0 to 10, Y is H, Na, K or Ag)
_{(C) -C n H 2n -PO} 3 Y 2 (n is an integer of 0, Y is H, Na, K, or Ag).

The “aromatic polyether” is a polyether having an aromatic ring such as a benzene ring.
The logarithmic viscosity (η _inh ) of the protonic acid group-containing aromatic polyether is usually 0.5 to 2.5 dl / g.

  The protonic acid group-containing aromatic polyether is preferably an aromatic polyether having a repeating structural unit represented by the following general formula (1) from the viewpoint of achieving excellent gas separation performance.

式（１）中、各Ｘはそれぞれ独立にＨ、プロトン酸基、−Ｃ_mＨ_2m+1（ｍは１〜１０の整数），−Ｃｌ，−Ｆ，−ＣＦ₃または−ＣＮであり、複数存在するＸのうち少なくとも一つはプロトン酸基であり、Ａ¹およびＡ²はそれぞれ独立して直接結合，−ＣＨ₂−，−Ｃ（Ｃ_pＨ_2p+1）₂−（ｐは１〜１０の整数），−Ｃ（ＣＦ₃）₂−，−Ｏ−，−ＳＯ₂−または−ＣＯ−であり、ｊ，ｋ，ｌはそれぞれ独立して０または１を示す。

In the formula (1), each X is independently H, protonic acid _{group, -C m H 2m + 1 (} m is an integer of from 1 to 10), - Cl, -F, a -CF ₃ or -CN, at least one of the plurality present X is a protonic acid group, a ¹ and a ² are each independently a direct _{bond, -CH 2 -, - C (} C p H 2p + 1) 2 - (p is 1 10 _{integer), - C (CF 3)} 2 -, - O -, - SO 2 - or a -CO-, showing j, k, l is 0 or 1 each independently.

When k and l are 1, two A ² exist, and in such a case, two A ² may be the same or different.
The protonic acid group-containing aromatic polyether is more preferably an aromatic polyether having a repeating structural unit represented by the following general formula (2).

式（２）中、各Ｘはそれぞれ独立にＨ、プロトン酸基、−Ｃ_mＨ_2m+1（ｍは１〜１０の整数），−Ｃｌ，−Ｆ，−ＣＦ₃または−ＣＮであり、複数存在するＸのうち少なくとも一つはプロトン酸基であり、Ａ¹は−ＳＯ₂−または−ＣＯ−であり、Ａ²は直接結合，−ＣＨ₂−，−Ｃ（Ｃ_pＨ_2p+1）₂−（ｐは１〜１０の整数），−Ｃ（ＣＦ₃）₂−，−Ｏ−，−ＳＯ₂−または−ＣＯ−であり、ｋ，ｌはそれぞれ独立して０または１を示す。

Equation (2), each X is independently H, protonic acid _{group, -C m H 2m + 1 (} m is an integer of from 1 to 10), - Cl, -F, a -CF ₃ or -CN, At least one of a plurality of X is a protonic acid group, A ¹ is —SO ₂ — or —CO—, A ² is a direct bond, —CH ₂ —, —C (C _p H _{2p + 1} ) _2- (p is an integer of 1 to 10), -C (CF ₃ ) _2- , -O-, -SO ₂ -or -CO-, and k and l each independently represent 0 or 1. .

When k and l are 1, two A ² exist, and in such a case, two A ² may be the same or different.
A further preferred example of the protonic acid group-containing aromatic polyether includes a copolymer composed of repeating structural units represented by the following formulas (3) and (4).

式（３）および（４）中、Ｒ₁〜Ｒ₆はそれぞれ独立に水素または−Ｃ_mＨ_2m+1（ｍは１〜８の整数）であり、２つ存在するＹは独立にＮａ，Ｋ，ＨまたはＡｇであり、式（３）で表わされる繰り返し構造単位の共重合比率（モル比）をｗ、式（４）で表わされる繰り返し構造単位の共重合比率（モル比）をｚとすると（ただしｗ＋ｚ＝１）、０．２≦ｗ≦０．８かつ０．８≧ｚ≧０．２である。

In formulas (3) and (4), R _{1 to} R ₆ are each independently hydrogen or —C _m H _{2m + 1} (m is an integer of 1 to 8), and two Ys are independently Na, K, H or Ag, the copolymerization ratio (molar ratio) of the repeating structural unit represented by the formula (3) is w, and the copolymerization ratio (molar ratio) of the repeating structural unit represented by the formula (4) is z. Then (where w + z = 1), 0.2 ≦ w ≦ 0.8 and 0.8 ≧ z ≧ 0.2.

  In the case of 0.2 ≦ w ≦ 0.8, the control of the carbon membrane structure by the sulfonic acid group is sufficient and preferable. The control of the carbon membrane structure is to control the balance of the existence of ultra-micropores and micropores, and by controlling the carbon membrane structure, both gas separation characteristics and transport characteristics can be achieved at a high level. Y is preferably Ag particularly from the balance of gas transport properties and selectivity.

The copolymer may be a random copolymer of repeating structural units represented by the above formulas (3) and (4), or may be a block copolymer.
As a most preferred example of the protonic acid group-containing aromatic polyether, a copolymer composed of repeating structural units represented by the following formulas (5) and (6) can be given.

式（５）中、Ｙは前記一般式（３）におけるＹと同じであり、式（５）で表わされる繰り返し構造単位の共重合比率（モル比）をｓ、式（６）で表わされる繰り返し構造単位の共重合比率（モル比）をｔとすると（ただしｓ＋ｔ＝１）、０．２≦ｓ≦０．８かつ０．８≧ｔ≧０．２である。

In the formula (5), Y is the same as Y in the general formula (3), the copolymerization ratio (molar ratio) of the repeating structural unit represented by the formula (5) is s, and the repetition represented by the formula (6) When the copolymerization ratio (molar ratio) of the structural units is t (where s + t = 1), 0.2 ≦ s ≦ 0.8 and 0.8 ≧ t ≧ 0.2.

In the case of 0.2 ≦ s ≦ 0.8, the control of the carbon membrane structure by the sulfonic acid group is sufficient and preferable.
Y is preferably Ag particularly from the balance of gas transport properties and selectivity.

The copolymer may be a random copolymer of repeating structural units represented by the above formulas (5) and (6), or may be a block copolymer.
A method for producing a monomer that becomes a protonic acid group-containing aromatic polyether as described above by polymerization is known and commercially available. Examples of the monomer include 2,2-bis (4-hydroxy-3,5-dimethyl-phenyl) propane (tetramethylbisphenol A (TMBPA)), 5,5′-carbonylbis (2-fluorobenzenesulfonic acid) Sodium) (DSDFBP) and 4,4′-difluorobenzophenone (DFBP). For example, TMBPA and DSDFBP react to produce a repeating structural unit represented by the above formula (3) (Y is Na and R _{1 to} R ₆ are all methyl groups). Moreover, the copolymerization ratio of a repeating structural unit can be made into the said range by adjusting the usage-amount of the monomer used for a polymerization reaction.

<Method for producing a membrane comprising a protonic acid group-containing aromatic polyether>
The film used as the raw material of the carbon film according to the present invention is composed of the above protonic acid group-containing aromatic polyether. The carbon membrane according to the present invention may be in the form of a flat sheet, for example, or may be in the form of a hollow fiber, that is, a hollow fiber membrane.

  When the carbon film according to the present invention is formed into a flat sheet or the like, for example, a polymer solution comprising an appropriate concentration of protonic acid group-containing aromatic polyether and a solvent is prepared. The solution may be cast as a film forming raw material. As other methods, a melt casting method and a spin coating method can also be used.

  Moreover, a hollow fiber can be spun using this polymer solution. When the carbon membrane according to the present invention is produced in the form of a hollow fiber, the hollow fiber may be produced by similarly spinning the hollow fiber using a spinneret using the polymer solution as a raw material.

  When the above molding is performed, the protonic acid group-containing aromatic polyether is carbonized by thermal decomposition performed later, and a carbon membrane having a flat sheet shape and a carbon membrane having a hollow fiber membrane shape, respectively. become.

  The solvent used here is a solvent which can dissolve the protonic acid group-containing aromatic polyether at a predetermined concentration and can be easily removed after molding, such as N, N-dimethylformamide. Is mentioned. Further, the concentration of the protonic acid group-containing aromatic polyether in the polymer solution may be, for example, 1 to 30% by weight with respect to the weight of the solvent.

  As described above, when molding is performed using a polymer solution as a raw material, the production of the carbon film of the present invention further includes a step of removing the used solvent after molding. In the solvent removal step, it is preferable to gradually evaporate most of the solvent at an initial stage and then remove the remaining solvent under heating conditions so that the molded product does not deform. For example, after the solvent is gradually evaporated at room temperature over 1 day to 10 days, the remaining solvent can be removed by drying at 150 to 300 ° C. in a vacuum environment.

[Carbon film]
<Method for producing carbon film>
The carbon membrane according to the present invention is produced by thermally decomposing a membrane comprising the protonic acid group-containing aromatic polyether. Usually, the film is thermally decomposed while controlling the heat treatment and annealing conditions.

  At this time, since it is necessary to suppress embrittlement of the film in order to obtain a robust carbon film, it is preferable to control the thermal decomposition temperature and time. Specifically, the thermal decomposition of the film is performed at a maximum heating temperature of 500 to 1000 ° C., preferably at a maximum heating temperature of 700 to 900 ° C. in a vacuum environment. Such thermal decomposition at a relatively low temperature is preferable in terms of saving energy consumption and improving the productivity of the carbon film.

  Depending on the composition of the protonic acid group-containing aromatic polyether used, the optimum thermal decomposition temperature for producing a carbon membrane having high separation performance in the separation of gases such as hydrogen, nitrogen, methane, and carbon dioxide varies. There is a case.

<Carbon film>
The carbon membrane obtained by the above manufacturing method is a robust carbon membrane having high gas separation / selection performance. Examples of the form of the carbon membrane include a flat sheet membrane and a hollow fiber membrane, and any carbon membrane can be used as a gas separation membrane.

  When the carbon film is in the form of a flat sheet, the thickness of the flat sheet carbon film is usually about 20 to 100 μm. On the other hand, when the carbon membrane is in the form of a hollow fiber membrane, the outer diameter of the hollow fiber membrane is usually about 300 to 1000 μm.

  As a method of using this carbon film, a gas mixture composed of a plurality of gases such as hydrogen, nitrogen, methane, carbon dioxide or a vapor mixture composed of a plurality of vapors such as hydrogen, nitrogen, methane, carbon dioxide is applied under pressure. A method of separating at least one gas or vapor from this mixture by contacting with a carbon membrane is mentioned.

  At this time, the carbon film is used to separate two kinds of gases or vapors having different molecular sizes. That is, the carbon membrane according to the present invention performs gas or vapor separation as a carbon molecular sieve membrane. For example, the carbon membrane can be used for hydrogen / nitrogen separation from a mixture containing hydrogen and nitrogen, and carbon dioxide / methane separation from a mixture containing carbon dioxide and methane.

The pressurization is usually a pressure of 3 atm to 30 atm.
In this specification, “vapor” is a component in a gas phase in which the state of a substance is different from a gas, and the state of the substance varies depending on the range of temperature and pressure. Vapor is distinguished from pure gas in that there is the same substance in a different state.

  The gas or vapor separation method may include a step of inspecting separation of hydrogen / nitrogen and carbon dioxide / methane.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by this. Each physical property was measured by the following method.

[Measurement method of physical properties]
(1) Logarithmic viscosity (η _inh )
The logarithmic viscosity of the polymer produced in the synthesis example is as follows. The polymer was dissolved in a mixed solvent of 50% by mass of N-methylpyrrolidinone / 50% by mass of dimethyl sulfoxide, and the solid content concentration was adjusted to 0.5 g / dl. Measured with

(2) Gas permeation characteristics
WH Lin, RH Vora, TS Chung, Gas Transport Properties of 6FDA-Durene / 1,4-phenylenediamine (pPDA) Copolyimides, [J. Polym. Sci .: Part B: Polym. Phys. 38 (2000) 2703-2713] The pure gas permeation coefficients of the (carbon) membranes produced in the examples and comparative examples were measured by the variable pressure constant volume method reported in the above. After measuring the permeation coefficient in the order of hydrogen, nitrogen, methane, carbon dioxide at 35 ° C. and 3.5 atm, the following equation (I) is used to calculate the gas obtained when the permeation reaches a stable state. The gas permeability coefficient P was determined from the pressure increase rate (dp / dt).

上記式（I）において、Ｐは、膜のガスに対するバーラー（Ｂａｒｒｅｒ）単位（１バーラー＝１×１０^-10 ｃｍ³（ＳＴＰ）・ｃｍ／（ｃｍ²・秒・ｃｍＨｇ））の透過係数であり、Ｖは、下流チャンバの容量（ｃｍ³）であり、Ａは、膜の有効面積（ｃｍ²）を表し、Ｌは、膜厚（ｃｍ）であり、Ｔは、測定温度（Ｋ）であり、ｄｐ／ｄｔは、下流チャンバにおける圧力変換器で測定される圧力増加速度（ｍｍＨｇ／ｓ）であり、さらに、上流チャンバにおける供給ガスの圧力は、ｐｓｉａ単位のｐ₀で与えられる。

In the above formula (I), P is a transmission coefficient of Barrer unit (1 barr = 1 × 10 ⁻¹⁰ cm ³ (STP) · cm / (cm ² · sec · cmHg)) with respect to the gas of the film. , V is the capacity (cm ³ ) of the downstream chamber, A is the effective area (cm ² ) of the film, L is the film thickness (cm), and T is the measurement temperature (K) , Dp / dt is the rate of pressure increase (mmHg / s) measured by the pressure transducer in the downstream chamber, and the pressure of the feed gas in the upstream chamber is given by p ₀ in psia.

Further, the ideal selectivity α _{A / B} of the film of the gas A with respect to the gas _B is defined as the following formula (II).

上記式（II）において、Ｐ_AおよびＰ_Bは、それぞれガスＡおよびガスＢについてのガス透過係数である。なお、Ｐ_A＞Ｐ_BとなるようにガスＡおよびガスＢを選定する。

In the above formula (II), P _A and P _B are gas permeability coefficients for gas A and gas B, respectively. Gas A and gas B are selected so that P _A > P _B is satisfied.

(3) Abbreviations of the compounds Abbreviations of the compounds used in the synthesis examples are as follows.
TMBPA: 2,2-bis (4-hydroxy-3,5-dimethyl-phenyl) propane (tetramethylbisphenol A)
DSDFBP: 5,5′-carbonylbis (sodium 2-fluorobenzenesulfonate)
DFBP: 4,4′-difluorobenzophenone DMSO: dimethyl sulfoxide NMP: N-methylpyrrolidinone DMF: N, N-dimethylformamide.

[Synthesis Example 1]
A reaction flask equipped with a stirrer, a thermometer and a condenser was charged with DFBP (0.525 mol) and 210 ml of 50% fuming sulfuric acid, and then reacted at 100 ° C. for 12 hours.

The obtained reaction solution was discharged into 1000 g of ice water and then neutralized with 210 g of NaOH. Next, 210 g of NaCl was added, and the crude product was dissolved by heating, then allowed to cool and left overnight.
After the precipitated crystals were filtered, 400 ml of water and 400 ml of ethanol were added to the crystals and dissolved by heating. Thereafter, the solution was allowed to cool and recrystallized.

  The precipitated crystals were filtered and then dried at 100 ° C. for 6 hours to obtain DSDFBP white crystals. The yield was 155.2 g (0.368 mol, yield 70%).

[Synthesis Example 2]
In a five-necked reactor equipped with a nitrogen inlet tube, a thermometer, a reflux condenser, and a stirring device, 37.16 g (0.088 mol) of DSDFBP obtained in Synthesis Example 1, 28.8 g (0.132 mol) of DFBP, TMBPA62 .57 g (0.220 mol) and potassium carbonate 36.49 g (0.264 mol) were weighed. DMSO (480 g) and toluene (120 g) were added thereto, and the mixture was stirred under a nitrogen atmosphere and heated at 140 ° C. for 8 hours to remove generated water out of the system, and then toluene was distilled off.

Then, after cooling the reaction solution to room temperature, 180 g of NMP was charged into the reactor for dilution. The obtained polymer solution was discharged into 2000 g of methanol, the precipitated polymer powder was filtered, washed with methanol and water, and then dried in a nitrogen atmosphere at 80 ° C. for 10 hours and at 150 ° C. for 8 hours to obtain sodium sulfonate. 109.1 g of group-containing aromatic polyether ketone (Na-SPEK) was obtained (91% yield). Η _inh of this Na-SPEK was 0.82 dl / g.

[Synthesis Example 3]
The Na-SPEK powder obtained in Synthesis Example 2 was immersed in 10% sulfuric acid for 24 hours. Thereafter, the obtained powder was washed with distilled water three times and dried at 120 ° C. under reduced pressure to obtain a sulfonic acid group-containing aromatic polyether ketone (H-SPEK).

[Synthesis Example 4]
The H-SPEK powder obtained in Synthesis Example 3 was immersed in a 10% silver nitrate aqueous solution. Then, the powder obtained similarly to the synthesis example 2 was wash | cleaned and dried, and the sulfonate silver group containing aromatic polyether ketone (Ag-SPEK) was obtained.

[Synthesis Example 5]
In a five-neck reactor equipped with a nitrogen inlet tube, a thermometer, a reflux condenser, and a stirrer, 23.35 g (0.107 mol) of DFBP, 30.13 g (0.106 mol) of TMBPA and 18.30 g (0.30 mol) of potassium carbonate were added. 132 mol) was weighed.

  NMP 160g was added to this solution, it stirred under nitrogen atmosphere, and it heated at 200 degreeC for 8 hours. The solution was then cooled to 100 ° C., and 300 g of NMP was charged into the reactor for dilution.

The obtained polymer solution is discharged into 1000 g of acetone, the precipitated polymer powder is filtered, washed with methanol and water, and then dried in a nitrogen atmosphere at 50 ° C. for 4 hours and at 180 ° C. for 4 hours. 44.6 g of ether ketone (PEK) was obtained (91% yield). Η _inh of this PEK was 0.59 dl / g.

[Example 1]
A polymer solution was prepared by dissolving 0.1 g of Na-SPEK obtained in Synthesis Example 2 in 4.9 g of DMF. This polymer solution was filtered through a Whatman filter (1 μmφ) to remove insoluble matters and dust particles, and the resulting solution was cast on a horizontal silicon wafer surrounded by a stainless steel ring at room temperature.

  DMF was gradually evaporated over about 5 days to obtain a homogeneous film with a thickness of about 50 μm. Next, the obtained film was heated at a rate of 10 ° C./min from room temperature to 250 ° C. and 0.2 ° C./min from 250 ° C. to 800 ° C. using a Centurion (registered trademark) Netech Qex vacuum furnace. And calcining by holding at 800 ° C. for 2 hours. Thereafter, the carbon film was obtained by cooling to room temperature at a rate of 1 ° C./min.

The gas permeability coefficient was measured using the obtained carbon membrane. The gas permeability coefficient and ideal selectivity are shown in Table 1 below.
[Example 2]
A carbon film was prepared and evaluated in the same manner as in Example 1 except that Na-SPEK was changed to H-SPEK obtained in Synthesis Example 3. The gas permeability coefficient and ideal selectivity are shown in Table 1 below.

[Example 3]
A carbon film was prepared and evaluated in the same manner as in Example 1 except that Na-SPEK was changed to Ag-SPEK obtained in Synthesis Example 4. The gas permeability coefficient and ideal selectivity are shown in Table 1 below.

[Comparative Example 1-3]
After producing a film made of an aromatic polyether by the same method as in Example 1-3, the physical properties of the film were evaluated without performing a baking operation. The evaluation results are shown in Table 1 below.

[Comparative Example 4]
Using the PEK obtained in Synthesis Example 5, a membrane made of PEK was prepared in the same manner as in Example 1, and then the gas permeability coefficient and ideal selectivity were evaluated for the obtained membrane without performing a baking operation. did. The evaluation results are shown in Table 1 below.

Claims (7)

A carbon film obtained by thermally decomposing a film made of an aromatic polyether having a proton acid group ,
The carbon film, wherein the aromatic polyether is a copolymer composed of repeating structural units represented by the following formulas (3) and (4):

[In the formulas (3) and (4), R _{1 to} R ₆ are each independently hydrogen or —C _m H _{2m + 1} (m is an integer of 1 to 8),
The two Ys are independently Na, K, H or Ag;
When the copolymerization ratio (molar ratio) of the repeating structural unit represented by the formula (3) is w and the copolymerization ratio of the repeating structural unit represented by the formula (4) is z (where w + z = 1), 0.2 ≦ w ≦ 0.8 and 0.8 ≧ z ≧ 0.2. ] The carbon film according to claim 1 , wherein the aromatic polyether is a copolymer composed of repeating structural units represented by the following formulas (5) and (6):

[In Formula (5), Y is each independently Na, K, H, or Ag,
When the copolymerization ratio (molar ratio) of the repeating structural unit represented by the formula (5) is s and the copolymerization ratio of the repeating structural unit represented by the formula (6) is t (where s + t = 1), 0.2 ≦ s ≦ 0.8 and 0.8 ≧ t ≧ 0.2. ]. In Formula (3), the carbon film according to claim 1, characterized in that Y is Ag. In the said General formula (5), Y is Ag, The carbon film of Claim 2 characterized by the above-mentioned. Carbon film according to any one of claims 1 to 4, the maximum temperature of heating in the thermal decomposition is characterized by a 500 to 1000 ° C.. Carbon film according to any one of claims 1-5 thickness of 20 to 100 [mu] m. A method for separating at least one gas or vapor from the mixture by contacting the gas mixture or the vapor mixture with a carbon membrane according to any one of claims 1 to 6 under pressure.