JP2006231095A - Carbonized film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and economical carbonized film for use in the separation of gas having excellent gas permeability and gas permselectivity and simple in manufacturing operation. <P>SOLUTION: The carbonized film for use in the separation of the gas is manufactured from phenylene oxide substantially comprising repeated units represented by formulae (a), (b), (c) and (d) (wherein R<SP>11</SP>-R<SP>12</SP>, R<SP>21</SP>-R<SP>22</SP>and R<SP>31</SP>-R<SP>34</SP>are each independently a hydrogen atom, a halogen atom, a lower alkyl group which may have a substituent, a lower alkylsilyl group which may have a substituent, a sulfone group, a carboxyl group or a diarylphosphino group which may have a substituent. R<SP>11</SP>-R<SP>12</SP>are not hydrogen at the same time, R<SP>21</SP>-R<SP>22</SP>are not hydrogen at the same time and all of R<SP>31</SP>-R<SP>34</SP>are not simultaneously hydrogen) and characterized in that the ratio of the sum [(b)+(c)+(d)] of the repeating units to [(a)+(b)+(c)+(d)] is 0-100%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a gas separation carbonized film comprising polyphenylene oxide, a precursor thereof, and a method for producing the gas separation carbonized film. In particular, the present invention relates to a carbon membrane for gas separation, a precursor thereof, and a method for producing the carbon membrane for gas separation, characterized by comprising polyphenylene oxide excellent in gas permeability and gas separation property.

A method using a membrane is known as a method of selectively separating and recovering a desired gas and using it effectively. Since this method has a feature that it is energy saving as compared with other gas separation and recovery methods, development of technology for efficiently separating and purifying a specific gas from a gas mixture has been actively studied.
As a study of materials constituting a gas separation membrane, a separation membrane using ceramics, special glass, or the like as a membrane material having chemical resistance and heat resistance has been reported. Although these separation membranes have a certain performance in terms of gas separation properties, it is difficult to form into a separation membrane shape, etc., and it is difficult to control and manufacture the gas separation function according to the purpose of use. There was a problem that it was difficult.
Carbon technology has attracted attention as a technique for revising this point. For example, a carbonized film obtained by applying a liquid thermosetting resin such as a phenol resin to the surface of a ceramic porous body and then carbonizing it in a non-oxidizing atmosphere. (See Patent Document 1), and a carbonized film (see Patent Document 2) obtained by carbonizing an asymmetric hollow fiber membrane made of aromatic polyimide and aromatic polyimide on the surface of the porous substrate. There has been reported a carbon film obtained by thermally decomposing a precursor formed by coating, heating and drying in an oxygen inert atmosphere (see Patent Document 3).
However, the former requires an expensive ceramic porous body, and it is necessary to go through a complicated process of repeating the coating operation many times. The latter is not satisfactory in terms of price, and the preparation of the carbon material There are problems such as complicated law.

Therefore, the appearance of a carbonized film for gas separation that is excellent in moldability and excellent in gas permeability as well as gas permeability with an inexpensive material and a simple process is desired.

JP-A-10-52629 JP-A-4-193334 JP 2003-286018 A

Accordingly, an object of the present invention is to provide a carbonized membrane for gas separation that is excellent in moldability and has excellent gas permeability as well as inexpensive materials and simple steps. Another object of the present invention is to provide a precursor for the gas separation carbonized film and a method for producing the gas separation carbonized film.

In the course of diligent research to solve the above problems, the inventors focused on poly (2,6-dimethyl-1,4-phenylene oxide) and produced a carbonized film from this polymer. Surprisingly, it has been found that it has excellent gas permeation selectivity similar to that of a polyimide carbide membrane, and has a faster gas permeability than a polyimide carbide membrane. In addition, the present inventor prepared a polyphenylene oxide derivative having a functional group added to this polyphenylene oxide by a simple one-step reaction, and a carbonized film obtained by carbonizing the polyphenylene oxide derivative can be molded according to the purpose. And it discovered that it had high gas separation performance. The present inventor has further studied based on these findings and finally reached the present invention.

（式中、Ｒ^１〜Ｒ^４は各々独立して、水素原子、ハロゲン原子、置換基を有してもよい低級アルキル基、置換基を有してもよいトリ低級アルキルシリル基、スルホン基、カルボキシル基、置換基を有してもよいジアリールホスフィノ基、−ＣＨ_２Ｒ^９を示し、Ｒ^９はハロゲン原子、置換基を有してもよいトリ低級アルキルシリル基、スルホン基、カルボキシル基、置換基を有してもよいジアリールホスフィノ基を示す。） That is, the invention of claim 1 is a carbon membrane for gas separation, characterized by being substantially composed of a carbide of a polyphenylene oxide polymer having the following repeating unit (1). Here, the carbide refers to a product obtained by carbonizing the polymer by a known method. The molecular weight of the polyphenylene oxide polymer is not limited as long as it is a size capable of producing a carbonized membrane for gas separation, but the lower limit is usually about 5,000 as the weight average molecular weight. The upper limit is not limited as long as it is a size capable of producing a carbonized membrane, particularly a carbonized membrane for gas separation.

(Wherein R ^{1 to} R ⁴ are each independently a hydrogen atom, a halogen atom, a lower alkyl group which may have a substituent, a tri-lower alkylsilyl group which may have a substituent, a sulfone group, A carboxyl group, a diarylphosphino group which may have a substituent, and —CH ₂ R ⁹ , wherein R ⁹ is a halogen atom, a tri-lower alkylsilyl group which may have a substituent, a sulfone group, a carboxyl group, (The diarylphosphino group which may have a substituent is shown.)

（式中、Ｒ^１１〜Ｒ^１２、Ｒ^２１〜Ｒ^２２、Ｒ^３１〜Ｒ^３４は各々独立して、水素原子、ハロゲン原子、置換基を有してもよい低級アルキル基、置換基を有してもよいトリ低級アルキルシリル基、スルホン基、カルボキシル基、置換基を有してもよいジアリールホスフィノ基を示すが、Ｒ^１１〜Ｒ^１２が共に水素原子ではなく、Ｒ^２１〜Ｒ^２２Ｒ^１１〜Ｒ^１２が共に水素原子ではなく、Ｒ^３１〜Ｒ^３４全てが水素原子ではない。） The invention of claim 2 comprises a polyphenylene oxide polymer having substantially the following repeating units and a ratio of 0 to 100% of the sum of the repeating units (b + c + d) and the sum of the repeating units (a + b + c + d). It is the carbonized film for gas separation characterized.

(In the formula, R ^{11 to} R ¹² , R ^{21 to} R ²² and R ^{31 to} R ³⁴ each independently have a hydrogen atom, a halogen atom, a lower alkyl group which may have a substituent, or a substituent. good tri-lower alkylsilyl group, a sulfone group, a carboxyl group, exhibit an optionally substituted diaryl phosphino ^group, rather than the R 11 ^{to R 12} are both hydrogen ^{atoms, R 21} ~R 22 R ¹¹ rather than to R ¹² are both hydrogen ^atoms, R 31 ^{to R 34} all are not a hydrogen atom.)

According to a third aspect of the present invention, in the polyphenylene oxide polymer according to the ^{first aspect} , at least one selected from R ¹ , R ² , R ³ and R ⁴ may have a substituent. The repeating unit (1) is a group, and the invention according to claim 4 further has at least one selected from R ¹ , R ² , R ³ , and R ⁴ having a substituent. It has the repeating unit (1) which is a carboxyl group which may be.
Invention of claim 5, wherein the polyphenylene oxide polymer of claim 2 wherein the at ^least one selected from ^{R 11 ~R 12, R 21 ~R} 22, R 31 ~R 34 is may have a substituent It has repeating units (b), (c) and (d) which are good tri-lower alkylsilyl groups, and the invention according to claim 6 further comprises R ^{11 to} R ¹² , R ^{21 to} R ^22. At least one selected from R ^{31 to} R ³⁴ has a repeating unit (b), (c), or (d) that is a carboxyl group.

A seventh aspect of the present invention is a gas separation carbonized film comprising a carbide of a polyphenylene oxide polymer according to one of the claims selected from the third to sixth aspects, and is asymmetric after carbonizing the polyphenylene oxide. A gas separation carbonized film characterized by having a mold structure.
The invention according to claim 8 is a carbon separation membrane precursor for gas separation, comprising the polyphenylene oxide polymer according to claim 1 selected from claims 1-6.
According to a ninth aspect of the invention, a polyphenylene oxide polymer according to one of the claims selected from the first to sixth aspects is formed into a predetermined separation membrane shape to form a carbonized film precursor, and the carbonized film precursor is formed. A gas separation carbonized film obtained by heating and carbonizing in an anaerobic atmosphere.
Accordingly, the invention according to claim 10 forms the carbonized film precursor by forming the polyphenylene oxide polymer according to one of the claims selected from claims 1 to 6 into a predetermined separation membrane shape, and forms the carbonized film precursor. It is a method for producing a carbonized film, in particular, a carbonized film for gas separation, characterized by heating and carbonizing a body in an anaerobic atmosphere.
In addition, this invention is also the carbonized film which consists of a carbide | carbonized_material of the polyphenylene oxide polymer of one Claim selected from Claims 1-6.

Hereinafter, the present invention will be described in detail.
One major feature of the present invention is a component constituting a carbon membrane for gas separation, and the component is a carbide of a polyphenylene oxide polymer substantially consisting of the repeating unit (1).
R ^{1 to} R ⁴ in the formula in the repeating unit (1) are each independently a hydrogen atom, a halogen atom, a lower alkyl group that may have a substituent, or a tri-lower alkyl that may have a substituent. A silyl group, a sulfone group, a carboxyl group, an optionally substituted diarylphosphino group, —CH ₂ R ⁹ , wherein R ⁹ is a halogen atom, an optionally substituted tri-lower alkylsilyl group, A diarylphosphino group which may have a sulfone group, a carboxyl group or a substituent is shown.
Here, the halogen atom includes a chlorine atom, a bromine atom or a fluorine atom.
Examples of the lower alkyl group include alkyl groups having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, n- or iso-propyl group, n-, sec- or tert-butyl group, n -There are amyl groups and the like. This alkyl group may be substituted with a halogen atom, cyano group, hydroxy group, alkoxy group, alkoxycarbonyl group, aryl group or the like.
The lower alkyl group of the tri-lower alkylsilyl group is the same as that exemplified above, and may be substituted with those exemplified above.
The aryl group of the diarylphosphino group is preferably a phenyl group, and this aryl group may be substituted with a halogen atom, a cyano group, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, or the like.
Each group ^{R 9} in the -CH ₂ R ⁹ are as described above.

A known method is used to measure the molecular weight of the polyphenylene oxide polymer of the present invention. For example, polyphenylene oxide is dissolved in a solvent and then measured by a gel permeation chromatogram (GPC) method.

In the present invention, the polyphenylene oxide composed of the repeating units (a), (b), (c), and (d) is selected from the polyphenylene oxide, and the polyphenylene oxide is used as a carbon membrane for gas separation. It is advantageous.
The abundance ratio of the repeating units (a), (b), (c), and (d) in the polyphenylene oxide polymer is not particularly limited. Here, R < ¹¹ > -R < ¹² >, R < ²¹ > -R < ²² >, R < ³¹ > -R < ³⁴ > in each repeating unit is the same as the above.

Among the above polyphenylene oxide polymers, when a polyphenylene oxide polymer having a tri-lower alkylsilyl group which may have a substituent is used, a gas separation membrane having excellent performance can be produced. When a polyphenylene oxide polymer having a tri-lower alkylsilyl group which may have a carboxyl group and a carboxyl group is used, a gas separation membrane having better performance can be produced.

A preferred method for preparing the polyphenylene oxide polymer defined in the present invention is patented to the starting polyphenylene oxide polymer, particularly poly (2,6-dimethyl-1,4-phenylene oxide) (hereinafter sometimes referred to as PPO). Although the method of introduce | transducing the functional group prescribed | regulated by a claim is mentioned, It is not limited to the method at all. Other methods include, for example, selecting an appropriate monomer capable of preparing the polyphenylene oxide specified in the claims, specifically a phenol compound that may have a functional group, and an appropriate catalyst such as an oxidative coupling catalyst. In the presence of the above, a method of oxidizing the monomer using oxygen gas or an oxygen-containing mixed gas, a method of preparing the polyphenylene oxide polymer by modifying the obtained polymer, and the like can be mentioned.

As the poly (2,6-dimethyl-1,4-phenylene oxide), any polymer having any molecular weight that can produce the polyphenylene oxide polymer can be used. About 5,000 to 1,000,000. The PPO can be easily obtained by purchasing a commercial product, but may be prepared by a known method.

For example, the polyphenylene oxide polymer can be prepared by reacting the PPO with a compound supplying a functional group to be introduced in a reaction system. Examples of the compound that supplies a functional group to be introduced include ClSO ₃ H, Br ₂ , Cl ₂ , Me ₃ SiCl, Ph ₂ PCl (Me represents a methyl group, Ph represents a phenyl group), CO ₂ , and the like. Although it can illustrate, it is not limited to these.
In this reaction, it is preferable that a compound such as n-R ⁸ Li (R ⁸ represents lower alkyl) is allowed to coexist so that the functional group is easily introduced into the polymer.
The reaction temperature is preferably about 60 ° C. from the temperature reached by the dry ice bath, and the reaction time is preferably several minutes to several tens of hours. More preferably, the reaction time is 10 minutes to 24 hours at a reaction temperature of 0 to 30 ° C.

A carbonized membrane for gas separation is produced using the polyphenylene oxide polymer thus prepared as a raw material. In the present invention, the shape of the carbon separation membrane for gas separation is not particularly limited, and for example, a hollow fiber membrane shape, a flat membrane shape, or a capillary membrane shape can be taken. Moreover, it can take the structure closely_contact | adhered to the support body surface like a ceramic porous body. Of these molded products, when practical aspects such as cost and pressure resistance are taken into consideration, it is most preferable that the molded product is formed into a hollow fiber membrane shape.

The method for producing the carbonized film is not particularly limited, and a known method may be employed. First, the polyphenylene oxide polymer prepared by the above method is dissolved in an arbitrary solvent to prepare a film forming stock solution. At this time, a substance that maintains the stability of the solution may be added in an amount within the initial target coordination. Examples of the solvent used here include methanol, chloroform, tetrahydrofuran, N, N-dimethylformamide, N-methyl-2-pyrrolidone and the like.
In the present invention, the polymer membrane obtained by molding the membrane-forming stock solution is called a carbonized membrane or a precursor of a carbon membrane for gas separation. For example, a hollow fiber membrane-like carbonized membrane precursor is as follows. Mold.
The membrane-forming stock solution is extruded into the coagulation liquid from the peripheral annular port of the double-pipe hollow fiber spinning nozzle, and mixed with the solvent of the membrane-forming stock solution from the circular nozzle at the center of the spinning nozzle. On the other hand, a non-soluble solvent is added to the coagulating liquid to form a hollow fiber-like product.
Here, as the coagulation liquid, there are ethanol, water, and saturated saline, which are mixed with the solvent of the film forming stock solution, but for the polyphenylene oxide polymer, ethanol, water, and saturated saline are used as the insoluble solvent. is there.
The temperature of the coagulation liquid is −20 ° C. to 60 ° C., preferably 0 ° C. to 30 ° C.

A flat film-like carbon film precursor or a gas separation carbon film precursor is cast or coated on a smooth glass plate with the above film-forming stock solution, and after heat treatment as necessary, the solvent is evaporated. Although it mixes with the solvent of the said film forming undiluted | stock solution, with respect to a polyphenylene oxide polymer, you may immerse in a poor solvent or a non-soluble solvent, and you may make it desolvate.

A capillary membrane-shaped carbonized film precursor or a gas separation carbonized film precursor is obtained by injecting the film-forming stock solution into a capillary film-forming apparatus and heat-treating the solvent as necessary to evaporate the solvent. Alternatively, the capillary membrane may be produced by extruding the membrane-forming stock solution into a coagulation solution as in the hollow fiber membrane production method. The temperature of the coagulation liquid is −20 ° C. to 60 ° C., preferably 0 ° C. to 30 ° C.
In these production methods, depending on the combination of the solvent and the coagulation liquid, it is possible to produce a separation membrane precursor having an asymmetric structure. For example, when the membrane-forming stock solution using N, N-dimethylformamide as a solvent is immersed in a coagulating solution of cold water to remove the solvent, a separation membrane precursor having an asymmetric structure is obtained. In particular, when a polyphenylene oxide polymer having a carboxyl group is used, a separation membrane precursor having an asymmetric structure is easily obtained, which is advantageous.
This hollow fiber-like material can be dried to obtain carbonized film precursors having various shapes or carbonized film precursors for gas separation. The carbonized film precursor or the carbonized film precursor for gas separation may be carbonized as it is. For example, the carbonized film precursor or the gas is obtained by performing heat treatment at a temperature lower than the carbonizing temperature, for example, about 150 to 300 ° C It is advantageous to infusibilize the separation carbonized film precursor. By performing this infusibilization treatment, the performance as a carbonized membrane or a carbonized membrane for gas separation is particularly improved.

The carbonized film precursor or the gas separating carbonized film precursor thus obtained can be carbonized by a known method to produce a carbonized film or a gas separating carbonized film. For example, the precursor is accommodated in a container, subjected to reduced pressure treatment of less than 1 torr, preferably less than 0.1 torr, and heat treatment. The heating conditions vary depending on the type and amount of the material constituting the precursor, and cannot be generally defined, but are usually 300 to 1000 ° C. and 24 hours or less in many cases. Preferably, it is 30 minutes to 4 hours at 550 to 850 ° C.
In addition, it is possible to produce a gas separation membrane by performing an overheat treatment in an anaerobic atmosphere substituted with an argon gas, a nitrogen gas, or the like without performing a decompression treatment.

By the method of the present invention, it is excellent in heat resistance, cold resistance, mechanical strength, and hot water resistance, and a carbon film precursor for gas separation or a carbon separation film precursor for gas separation is obtained with a polyphenylene oxide polymer used as an engineer plastic. The precursor is preferably carbonized after infusibilization to obtain a carbonized film or a gas separating carbonized film, so that the carbonized film precursor or the gas separating carbonized film precursor is heated even when heated to a relatively high temperature during carbonization. Thus, a carbonized film having a uniform pore diameter or a carbonized film for gas separation with few structural defects can be obtained. In addition, polyphenylene oxide polymer has excellent solvent solubility, so it can be made into a hollow fiber and formed into a film by a wet process. Carbonized carbon film precursors for various shapes or carbonized film precursors for gas separation can be molded and carbonized. Therefore, various shapes of carbonized films can be easily manufactured. Furthermore, since it is excellent in moldability, the carbonized film can be filled in the container in a compact manner, so that it is possible to manufacture a small and efficient gas separation device.

In the present invention, in particular, when a polyphenylene oxide polymer having a tri-lower alkylsilyl group which may have a substituent is used, a gas separation membrane having excellent performance can be produced. If a polyphenylene oxide polymer having a tri-lower alkylsilyl group and a carboxyl group may be used, a gas separation membrane having an asymmetric structure can be produced. This gas separation membrane having an asymmetric structure is advantageous in that it has a particularly excellent gas separation ability.

The method of using the carbonized film of the present invention can be the same as a known carbonized film, but is particularly useful as a carbonized film for gas separation. It is particularly useful in fields such as hydrogen production, carbon dioxide separation and recovery, exhaust gas separation and recovery, natural gas separation, gas dehumidification, and production of oxygen from air.

According to the present invention, a carbonized membrane and a carbonized membrane for gas separation can be produced with an inexpensive material and a simple process. The gas separation membrane obtained by the present invention is excellent in gas permeability and gas separation properties. Moreover, the moldability is also excellent. The gas separation membrane obtained by the present invention enables separation of many kinds of gases, but is particularly effective for separation of hydrogen, helium gas, carbon dioxide, and oxygen. It is also effective for the production of hydrogen and oxygen.

Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to the following examples.

Production of PPO carbonized film (preparation of stock solution for carbonized film production)
5.0 g of PPO (Aldrich No. 181781) was dissolved in 23.6 g of chloroform to prepare a film-forming stock solution of 17.5% by weight of PPO.
(Creation of carbonized film precursor)
The obtained membrane-forming stock solution was extruded into the ethanol coagulation tank at the same time through the membrane-forming stock solution from the annular port of the hollow tube spinning nozzle having a double-pipe structure, and ethanol from the circular port. A film (carbonized film precursor) was obtained.
Using a test gas (He, H ₂ , CO ₂ , O ₂ , N ₂ ), the gas separation performance of the carbide film precursor was examined.
The results are shown in Table 1.
(Manufacture of carbonized film intermediate)
Next, the obtained hollow fiber membrane was heated to 280 ° C. at a rate of 8 ° C./min in an air atmosphere in a muffle furnace, heated at this temperature for 45 minutes, and then allowed to cool, and a carbonized film precursor Infusibilization treatment was performed.
(Manufacture of carbonized film)
Subsequently, the carbonized film intermediate obtained above was carbonized using a vacuum electric furnace. In this operation, the vacuum electric furnace was first depressurized to 10 ⁻⁵ torr or less, heated to 650 ° C. at a rate of 10 ° C./min, heated at this temperature for 2 hours, allowed to cool, Obtained. This membrane was a symmetrical membrane.
The gas separation performance of the carbonized membrane obtained using the same test gas as described above was examined.
The method is as follows.
A test gas was supplied to the inner surface of the hollow fiber module attached to the hollow fiber gas permeability measuring device at a constant pressure, and the permeated gas flow rate was measured with a flow meter. At this time, the gas separation performance of the hollow fiber carbonized membrane was determined from the gas permeation coefficient P and the gas permeation rate Q obtained by the following equations. Further, the gas separation coefficient α was determined from the ratio of P or Q.
P = {gas permeation flow rate (cm ³ · STP) × film thickness (cm)} ÷ {membrane area (cm ² ) × time (seconds) × pressure difference (cmHg)}
Q = {gas permeation flow rate (cm ³ · STP)} ÷ {membrane area (cm ² ) × time (seconds) × pressure difference (cmHg)}
The results are shown in Table 2.

Preparation of brominated PPO carbonized film ((a): (b) + (d) = 2: 98)
(Preparation of stock solution for carbonized film production)
4.8 g of PPO (same as in Example 1: the same applies hereinafter) was dissolved in 480 ml of chloroform, and a solution of 6.4 g of bromine in 20 ml of chloroform was added dropwise thereto and reacted overnight at room temperature to obtain brominated PPO. The reaction formula is shown below. This brominated PPO (2.3 g) was dissolved in chloroform (7.6 g) to prepare a membrane-forming stock solution of brominated PPO (23 wt%).
Using this stock solution for carbonized film production, the same operation as in Example 1 was performed to obtain a carbonized film. This membrane was a symmetrical membrane. The gas separation performance of the carbonized film precursor and the carbonized film obtained using the same test gas as described above was examined.
The results are shown in Tables 1 and 2.

Preparation of sulfonated PPO carbonized membrane (functional group introduced = SO ₃ H, (a): (b) + (d) = 56:44)
(Preparation of stock solution for carbonized film production)
15.0 g of PPO was dissolved in 300 ml of chloroform, and a solution of 17.6 g of chlorosulfuric acid in 25 ml of chloroform was added dropwise thereto and reacted at room temperature for 30 minutes to obtain a sulfonated PPO. The reaction formula is shown below. 3.0 g of this sulfonated PPO was dissolved in 9.0 g of methanol to prepare a membrane forming stock solution of 25% by weight of sulfonated PPO.
(Preparation of carbonized film precursor)
The obtained membrane-forming stock solution was extruded from the annular port of the double-pipe hollow fiber spinning nozzle, and the saturated salt (NaCl) water was simultaneously extruded from the circular port into the saturated saline coagulation tank. After being immersed in HCl solution, it was air-dried at room temperature to obtain a carbonized film precursor.
The gas separation performance of the hollow fiber membrane was examined using the same test gas as described above.
The results are shown in Table 1.
Using this stock solution for carbonized film production, the same operation as in Example 1 was performed to obtain a carbonized film. This membrane was a symmetrical membrane. The gas separation performance of the carbonized membrane obtained using the same test gas as described above was examined. The results are shown in Table 2.

Preparation of trimethylsilylated PPO separation membrane (Introduced functional group = SiMe ₃ , (a): (b) + (c) + (d) = 1: 99)
(Adjustment of stock solution for carbonized film production)
Dissolve 5.0 g of PPO in 250 ml of tetrahydrofuran, add 27.6 ml of 1.6 mol / l n-butyllithium hexane solution and stir at room temperature for 1 hour, then add 4.6 g of chlorotrimethylsilane dropwise and continue for 10 minutes at room temperature. Reaction was performed to obtain trimethylsilylated PPO. The reaction formula is shown below. 3.0 g of this trimethylsilylated PPO was dissolved in 12.0 g of chloroform to prepare a film-forming stock solution of 20% by weight of brominated PPO.
Using this stock solution for carbonized film production, the same operation as in Example 1 was performed to obtain a carbonized film. This membrane was a symmetrical membrane. The gas separation performance of the carbonized film precursor and the carbonized film obtained using the same test gas as described above was examined.
The results are shown in Tables 1 and 2.

Preparation of diphenylphosphinolated PPO separation membrane (functional group introduced = PPh ₂ , (a): (b) + (c) + (d) = 20: 80)
(Adjustment of stock solution for carbonized film production)
Dissolve 5.0 g of PPO in 250 ml of tetrahydrofuran, add 27.6 ml of 1.6 mol / l n-butyllithium hexane solution and stir at room temperature for 1 hour, drop 9.7 g of chlorodiphenylphosphine, To give diphenylphosphinoylated PPO. The reaction formula is shown below. This diphenylphosphinolated PPO (3.0 g) was dissolved in chloroform (9.0 g) to prepare a membrane forming stock solution of diphenylphosphinoylated PPO (25% by weight).
(Adjustment of carbonized film precursor)
Using the obtained membrane-forming stock solution, the same operation as in Example 1 was performed to obtain a separation membrane precursor. Using the same test gas as described above, the gas separation performance of the carbonized film precursor was examined.
The results are shown in Table 1.
(Manufacture of carbonized film intermediate)
Next, the obtained hollow fiber membrane was heated to 150 ° C. at a rate of 8 ° C./min in an air atmosphere in a muffle furnace, heated at this temperature for 2 hours, and then allowed to cool, whereby a separation membrane precursor Infusibilization treatment was performed.
(Manufacture of carbonized film)
Then, the operation similar to Example 1 and Example 1 was performed using the vacuum electric furnace, and the carbonized film was obtained. This membrane was a symmetrical membrane. The gas separation performance of the carbonized membrane obtained using the same test gas as described above was examined.
The results are shown in Table 2.

表中、PHeはヘリウムガスの時の分離膜の気体透過係数を示す（以下、同様）。単位は１０^−１０ｃｍ^３（ＳＴＰ）ｃｍ・ｃｍ^２・ｓｅｃ・ｃｍＨｇである。測定温度は２５℃であった（以下同様）。ガスの分離係数αHe/N₂は測定値Ｐの比から求める。（以下同様）。

In the table, PHe indicates the gas permeability coefficient of the separation membrane when helium gas is used (hereinafter the same). The unit is 10 ⁻¹⁰ cm ³ (STP) cm · cm ² · sec · cmHg. The measurement temperature was 25 ° C. (the same applies hereinafter). The gas separation factor αHe / N ₂ is determined from the ratio of the measured values P. (The same applies hereinafter).

Preparation of carboxylated PPO separation membrane (functional group introduced = CO ₂ H, (a): (b) + (c) + (d) = 32: 68)
(Adjustment of stock solution for carbonized film production)
Dissolve 5.0 g of PPO in 200 ml of tetrahydrofuran, add 18.0 ml of 1.6 mol / l n-butyllithium hexane solution and stir at room temperature for 1 hour, add excess dry ice, and react at room temperature for 30 minutes. To give carboxylated PPO. The reaction formula is shown below. This carboxylated PPO (3.0 g) was dissolved in dimethylacetamide (12.0 g) to prepare a film-forming stock solution of carboxylated PPO (20 wt%).
(Adjustment of carbonized film precursor)
The obtained membrane forming stock solution is extruded from the annular port of the hollow fiber spinning nozzle having a double-pipe structure, and water is extruded from the circular port into the water coagulation tank at the same time. A carbonized film precursor was obtained.
The gas separation performance of the carbonized film precursor obtained using the same test gas as described above was examined.
The results are shown in Table 3.
Using this carbonized film precursor, the same operation as in Example 1 was performed to obtain a carbonized film. This membrane was an asymmetric membrane. The gas separation performance of the carbonized membrane obtained using the same test gas as described above was examined.
The results are shown in Table 4.

Preparation of carboxyl-trimethylsilylated PPO carbonized film (Introduced functional group = CO ₂ H, Introduced functional group = SiMe ₃ , ratio of former to latter = 30: 70, (a): (b) + (c ) + (d) = 1:99)
(Adjustment of stock solution for carbonized film production)
PPO (5.0 g) was dissolved in tetrahydrofuran (200 ml), 1.6 mol / l n-butyllithium hexane solution (18.0 ml) was added thereto, and the mixture was stirred at room temperature for 1 hour. After adding 4.6 g of chlorotrimethylsilane to n-butyllithium so as to be 0.7 equivalent and reacting at room temperature for 10 minutes, adding excess dry ice and reacting at room temperature for 30 minutes, carboxyl-trimethylsilylation Got PPO. This carboxyl-trimethylsilylated PPO (3.0 g) was dissolved in dimethylacetamide (12.0 g) to prepare a film-forming stock solution of carboxyl-trimethylsilylated PPO (20% by weight).
(Formation of carbonized film precursor)
The same operation as in Example 6 was performed using the obtained film forming stock solution to obtain a carbonized film precursor.
Using this carbonized film precursor, the same operation as in Example 1 was performed to obtain a carbonized film. This membrane was an asymmetric membrane. The gas separation performance of the carbonized film precursor and the carbonized film obtained using the same test gas as described above was examined.
The results are shown in Table 3 and Table 4.

表中、ＱHeはヘリウムガスの時の分離膜の気体透過係数を示す（以下、同様）。単位は１０^−６ｃｍ^３（ＳＴＰ）／ｃｍ^２・ｓｅｃ・ｃｍＨｇである。測定温度は２５℃であった。（以下同様）。ガスの分離係数αHe/N₂は測定値Ｑの比から求める。（以下同様）。

In the table, QHe indicates the gas permeability coefficient of the separation membrane when helium gas is used (hereinafter the same). The unit is 10 ⁻⁶ cm ³ (STP) / cm ² · sec · cmHg. The measurement temperature was 25 ° C. (The same applies hereinafter). The gas separation factor αHe / N ₂ is determined from the ratio of the measured values Q. (The same applies hereinafter).

Claims (10)

A carbon membrane for gas separation, characterized by comprising a carbide of a polyphenylene oxide polymer substantially comprising the following repeating unit (1).

(Wherein R ^{1 to} R ⁴ are each independently a hydrogen atom, a halogen atom, a lower alkyl group which may have a substituent, a tri-lower alkylsilyl group which may have a substituent, a sulfone group, A carboxyl group, a diarylphosphino group which may have a substituent, and —CH ₂ R ⁹ , wherein R ⁹ is a halogen atom, a tri-lower alkylsilyl group which may have a substituent, a sulfone group, a carboxyl group, (The diarylphosphino group which may have a substituent is shown.) The carbon membrane for gas separation according to claim 1, wherein the polyphenylene oxide polymer is substantially composed of the following repeating units, and the ratio of the sum (b + c + d) of the repeating units to (a + b + c + d) is 0 to 100%.

(In the formula, R ^{11 to} R ¹² , R ^{21 to} R ²² and R ^{31 to} R ³⁴ each independently have a hydrogen atom, a halogen atom, a lower alkyl group which may have a substituent, or a substituent. A tri-lower alkylsilyl group, a sulfone group, a carboxyl group, and a diarylphosphino group which may have a substituent, provided that R ^{11 to} R ¹² are not hydrogen atoms, and R ^{21 to} R ²² are Both are not hydrogen atoms, and all of R ^{31 to} R ³⁴ are not hydrogen atoms at the same time.) The polyphenylene oxide polymer has a repeating unit (1) in which at least one selected from R ¹ , R ² , R ³ and R ⁴ is a tri-lower alkylsilyl group which may have a substituent. The carbonized membrane for gas separation according to claim 1. The gas separation according to claim 3, wherein the polyphenylene oxide polymer further has a repeating unit (1) in which at least one selected from R ¹ , R ² , R ³ and R ⁴ is a carboxyl group. Carbonized film. The repeating unit (b) in which the polyphenylene oxide polymer is a tri-lower alkylsilyl group in which at least one selected from R ^{11 to} R ¹² , R ^{21 to} R ²² and R ^{31 to} R ³⁴ may have a substituent. The carbonized membrane for gas separation according to claim 2, comprising: (c) and (d). The polyphenylene oxide polymer is a repeating unit (b), (c), and (d) in which at least one selected from R ^{11 to} R ¹² , R ^{21 to} R ²² , R ^{31 to} R ³⁴ is a carboxyl group, The carbonized membrane for gas separation according to claim 5, further comprising: A gas separation carbonized film made of a carbide of a polyphenylene oxide polymer according to one of claims 3 to 6, which has an asymmetric structure after carbonization. A carbon separation film precursor for gas separation, comprising the polyphenylene oxide polymer according to claim 1 selected from claims 1 to 6. A polyphenylene oxide polymer according to one claim selected from claims 1 to 6 is molded into a predetermined separation membrane shape to form a carbonized film precursor, and the carbonized film precursor is heated and carbonized in an anaerobic atmosphere. A carbon separation membrane for gas separation characterized by the above. A polyphenylene oxide polymer according to one of claims 1 to 6 selected from claims 1 to 6 is formed into a predetermined separation membrane shape to form a carbonized film precursor, and the carbonized film precursor is heated and carbonized in an anaerobic atmosphere. A method for producing a carbonized film, comprising: