JP2001081193A - Polyimide, method for producing the same, and gas separation membrane using the same - Google Patents

Abstract

(57) [Problem] To provide a gas separation membrane which is excellent in heat resistance, chemical resistance, film forming property, etc., and has high gas permeability and high selectivity. The following formula (I): (However, S is a tetravalent organic group, R is a halogen atom, a methyl group, a trifluoromethyl group or a methoxy group. M is 0
It means an integer of ~ 4. Further, n means an integer of 50 to 1800. And a gas separation membrane using the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas separation membrane made of polyimide containing a diacetylene skeleton and having excellent permeability. The gas separation membrane of the present invention not only has excellent permeation performance, but also has extremely good heat resistance, chemical resistance, and the like.

[Industrial applications]

[0002] Gas separation using a separation membrane is useful in various fields because it requires less energy for separation than other methods. The gas separation membrane of the present invention, for example, separation and recovery of hydrogen during the synthesis of ammonia, recovery of carbon dioxide from waste gas from thermal power plants and waste incinerators, removal of sulfur oxides and nitrogen oxides, off-gas from oil fields Recovery of carbon dioxide, removal of hydrogen sulfide and carbon dioxide from natural gas and separation of helium, recovery of gasoline leaked from gasoline distribution stations, pervaporation separation of volatile substance mixture liquid, removal of gas dissolved in liquid Used for removal, separation of oxygen and nitrogen in air, etc.

[0003]

2. Description of the Related Art Conventionally, a cellulose acetate membrane is well known as a gas separation membrane having excellent properties such as heat resistance, solubility, and film forming properties. Etc. are low and are not satisfactory for practical use. Polysulfone semipermeable membranes are industrially produced as separation membranes with improved heat resistance, but their permeation performance is insufficient and not satisfactory. Also, a silicone membrane is known as an oxygen selective permeable membrane, but silicone is not industrially satisfactory because of insufficient mechanical strength.
Recently, aromatic polyimide resins with high elastic modulus, high strength, low expansion properties, and excellent heat resistance have begun to be studied, but in practice, emphasis is placed on selective separation and heat resistance, and solubility in various solvents, In addition, a satisfactory gas separation membrane cannot be obtained, and a practical gas separation membrane has not been obtained.

[0004]

OBJECTS AND SUMMARY OF THE INVENTION An object of the present invention is to provide a gas separation membrane having excellent permselectivity and excellent heat resistance, chemical resistance, film forming properties, and the like.

The inventor of the present invention has intensively studied to solve the problems of the above-mentioned polyimide gas separation membrane and to obtain a polyimide gas separation membrane excellent in permselectivity. As a result, a gas separation membrane made of polyimide using tetracarboxylic dianhydride, which is a precursor of a tetravalent residue forming a polyimide, and condensation-polymerizing a specific diamine component forming a divalent residue. As a result, the present inventors have found that the above problem can be solved and completed the present invention.

[0006] The first invention of the present application is the following formula (I):

Embedded image (However, S is a tetravalent organic group, R is a halogen atom, a methyl group, a trifluoromethyl group or a methoxy group. M is 0
It means an integer of ~ 4. Further, n means an integer of 50 to 1800. The present invention provides a polyimide having a repeating structural unit represented by the formula (1).

Further, the second invention of the present application is the following formula (II):

Embedded image (Where S means a tetravalent organic group) and a tetracarboxylic dianhydride represented by the following formula (III):

Embedded image (Where R is a halogen atom, a methyl group, a trifluoromethyl group or a methoxy group; m represents an integer of 0 to 4), which is characterized by condensation polymerization with a diamine having a diacetylene skeleton represented by the formula: The following formula (I):

Embedded image (However, S, R, m and n are the same as described above.) The present invention provides a method for producing a polyimide having a repeating structural unit. Further, the third invention of the present application is a gas separation membrane formed of the polyimide.

DETAILED DESCRIPTION OF THE INVENTION The first invention is a polyimide having a repeating structural unit represented by the above general formula (I).

In the formula (I), S is a tetravalent organic group and is derived from an acid dianhydride represented by the following formula (II).

Embedded image

Specific examples of such an acid dianhydride include:
Pyromellitic dianhydride, 3,3'-biphenyltetracarboxylic dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, 3'4,4'-benzophenonetetracarboxylic dianhydride 4,4'-oxydiphthalic anhydride, 3,3'4,4'-diphenylsulfonetetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 3,4, 9,10-perylenetetracarboxylic dianhydride and the like. In consideration of solubility in various solvents and film-forming properties, 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride is preferred.

The polyimide of the formula (I) of the present invention comprises the above acid dianhydride and the following formula (III):

Embedded image (In the formula, R and m are the same as described above.) Having a structure of polycondensation with a diamine having a diacetylene skeleton.

Specific examples of the diamine component include 4
-[4- (4-aminophenyl) buta-1,3-diynyl]
Phenylamine, 4- [4- (4-amino-3-fluorophenyl) buta-1,3-diynyl] -2-fluorophenylamine, 4- [4- (4-amino-3-chlorophenyl)
Buta-1,3-diynyl] -2-chlorophenylamine,
4- [4- (4-amino-3-bromophenyl) buta-1,
3-diynyl] -2-bromophenylamine, 4- [4-
(4-amino-3-methylphenyl) buta-1,3-diynyl] -2-methylphenylamine, 4- {4- [4-amino-3- (trifluoromethyl) phenyl] buta-1,3-
Diynyl} -2- (trifluoromethyl) phenylamine,
4- [4- (4-amino-3,5-dimethylphenyl) buta-1,3-diynyl] -2,6-dimethylphenylamine, 4- [4- (4-amino-2,5-dimethylphenyl) )
Buta-1,3-diynyl] -2,5-dimethylphenylamine, 4- {4- [4-amino-2,5-bis (trifluoromethyl) phenyl] buta-1,3-diynyl} -2, 5-bis (trifluoromethyl) phenylamine,

4- [4- (4-amino-2,5-difluorophenyl) buta-1,3-diynyl] -2,5-difluorophenylamine, 4- [4- (4-amino-2) , 5-Dichlorophenyl) buta-1,3-diynyl] -2,5-dichlorophenylamine, 4- [4- (4-amino-2,5-dibromophenyl) buta-1,3-diynyl] -2,5 -Dibromophenylamine, 4- [4- (4-amino-2,3,6-
Trifluorophenyl) but-1,3-diynyl] -2,3,
5-trifluorophenylamine, 4- [4- (4-amino-2,3,6-trichlorophenyl) buta-1,3-diynyl] -2,3,5-trichlorophenylamine, 4- [4-
(4-amino-2,3,6-tribromophenyl) buta-
1,3-diynyl] -2,3,5-tribromophenylamine, 4- [4- (4-amino-2,3,6-trimethylphenyl) buta-1,3-diynyl] -2,3, 5-trimethylphenylamine,

4- {4- [4-amino-2,3,6-tris
(Trifluoromethyl) phenyl] buta-1,3-diynyl}
-2,3,5-tris (trifluoromethyl) phenylamine, 4- [4- (4-amino-2,3,5,6-tetrafluorophenyl) buta-1,3-diynyl] -2,3 , 5,6-tetrafluorophenylamine, 4- [4- (4-amino-
2,3,5,6-tetrachlorophenyl) buta-1,3-diynyl] -2,3,5,6-tetrachlorophenylamine,
4- [4- (4-amino-2,3,5,6-tetrabromophenyl) buta-1,3-diynyl] -2,3,5,6-tetrabromophenylamine, 3- [4- ( 3-aminophenyl) but-1,3-diynyl] phenylamine, 5- [4-
(3-amino-4-fluorophenyl) buta-1,3-diynyl] -2-fluorophenylamine,

5- [4- (3-amino-4-chlorophenyl) buta-1,3-diynyl] -2-chlorophenylamine, 5- [4- (3-amino-4-bromophenyl) buta-1, 3-diynyl] -2-bromophenylamine, 5-
[4- (3-Amino-4-methylphenyl) buta-1,3-
Diynyl] -2-methylphenylamine, 5- {4- [3
-Amino-4- (trifluoromethyl) phenyl] buta-1,
3-diynyl} -2- (trifluoromethyl) phenylamine, 5- [4- (3-amino-4,6-difluorophenyl)
Buta-1,3-diynyl] -2,4-difluorophenylamine, 5- [4- (3-amino-4,6-dichlorophenyl) buta-1,3-diynyl] -2,4-dichlorophenylamine, 5- [4- (3-amino-4,6-dibromophenyl) buta-1,3-diynyl] -2,4-dibromophenylamine, 5- [4- (3-amino-4,6-dimethylphenyl) ) But-1,3-diynyl] -2,4-dimethylphenylamine,

5- {4- [3-amino-6- (1,1-difluorophenyl) -4- (trifluoromethyl) phenyl] buta-1,3-diynyl} -2,4-bis (tri (Fluoromethyl)
Phenylamine, 5- [4- (3-amino-4,5,6-trifluorophenyl) buta-1,3-diynyl] -2,3,4
-Trifluorophenylamine, 5- [4- (3-amino-
4,5,6-trichlorophenyl) buta-1,3-diynyl] -2,3,4-trichlorophenylamine, 5- [4-
(3-amino-4,5,6-tribromophenyl) buta-
1,3-diynyl] -2,3,4-tribromophenylamine, 5- [4- (3-amino-4,5,6-trimethylphenyl) buta-1,3-diynyl] -2,3, 4-trimethylphenylamine, 5- {4- [3-amino-6- (1,1-
Difluoroethyl) -4,5-bis (trifluoromethyl) phenyl] buta-1,3-diynyl} -2,3,4-tris (trifluoromethyl) phenylamine, 5- [4- (3-amino-2) , 4,5,6-tetrafluorophenyl) buta-1,3-
Diynyl] -2,3,4,6-tetrafluorophenylamine,

5- [4- (3-amino-2,4,5,6-tetrachlorophenyl) buta-1,3-diynyl] -2,3,
4,6-tetrachlorophenylamine, 5- [4- (3-
Amino-2,4,5,6-tetrabromophenyl) buta-
1,3-diynyl] -2,3,4,6-tetrabromophenylamine, 4- [4- (4-amino-3-methoxyphenyl) buta-1,3-diynyl] -2-methoxyphenylamine, 4- [4- (4-amino-2-methoxyphenyl)
Buta-1,3-diynyl] -2-methoxyphenylamine, 4- [4- (4-amino-2-methoxyphenyl) buta-1,3-diynyl] -3-methoxyphenylamine,
5- [4- (3-amino-4-methoxyphenyl) buta-
1,3-diynyl] -2-methoxyphenylamine, 5-
[4- (3-Amino-5-methoxyphenyl) buta-1,3
-Diynyl] -2-methoxyphenylamine, 3- [4-
(3-amino-6-methoxyphenyl) buta-1,3-diynyl] -4-methoxyphenylamine, 3- [4- (3
-Amino-4-methoxyphenyl) buta-1,3-diynyl] -2-methoxyphenylamine, 3- [4- (3-amino-2-methoxyphenyl) buta-1,3-diynyl]
-2-methoxyphenylamine, 3- [4- (3-amino-6-methoxyphenyl) buta-1,3-diynyl] -2
-Methoxyphenylamine, 3- [4- (3-amino-5
-Methoxyphenyl) buta-1,3-diynyl] -2-methoxyphenylamine and the like. Considering solubility in various solvents and film forming property among these, 4-
[4- (4-aminophenyl) buta-1,3-diynyl] phenylamine, 3- [4- (3-aminophenyl) buta-
1,3-diynyl] phenylamine, 4- [4- (4-amino-3-methylphenyl) buta-1,3-diynyl] -2
-Methylphenylamine, 4- [4- (4-amino-2,
5-dimethylphenyl) but-1,3-diynyl] -2,5
-Dimethylphenylamine, 5- [4- (3-amino-4
-Methylphenyl) but-1,3-diynyl] -2-methylphenylamine, 4- [4- (4-amino-3-methoxyphenyl) buta-1,3-diynyl] -2-methoxyphenylamine, -[4- (4-amino-2-methoxyphenyl) buta-1,3-diynyl] -3-methoxyphenylamine, 5- [4- (3-amino-4-methoxyphenyl) buta-1,3- Diynyl] -2-methoxyphenylamine, 3- [4- (3-amino-6-methoxyphenyl)
Buta-1,3-diynyl] -4-methoxyphenylamine is preferred.

The polyimide of the present invention has an intrinsic viscosity of 0.4 to 3.0, preferably 0.5 to 2.5, as measured with a solution of N-methyl-2-pyrrolidone, 0.5 g dissolved in 1 deciliter, at 30 ° C. 0. If the intrinsic viscosity is too low, the self-supporting property of the gas separation membrane is poor, and the mechanical strength is insufficient. On the other hand, if the intrinsic viscosity is too large, it is difficult to obtain a uniform film-forming solution, and it becomes difficult to form a film. Therefore, in the above formula, n is from 50 to 1800, preferably from 150 to 1
600.

(Production method) The novel polyimide of the present invention has the general formula (II):

Embedded image (Wherein S is as defined above) and a tetracarboxylic dianhydride represented by the following formula (III):

Embedded image (R and m are the same as described above). The ratio of the two used for double-jumping is 1: 0.95 to 1: 1 in molar ratio.
05, preferably about equimolar.

The polymerization method is not particularly limited, and a known polymerization method can be used in the production of polyimide by polycondensation of tetracarboxylic dianhydride and diamine.

As the solvent used in the polymerization reaction, N-
Methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, diglyme, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidin, hexamethylphosphoramide, m-cresol and the like. These may be used alone or in combination. The use amount of the solvent with respect to the raw material is not particularly limited, but usually it is preferable to use 3 to 30% by weight.

In the reaction, a diamine component and a tetracarboxylic dianhydride component are mixed and reacted at a temperature lower than room temperature for usually 3 to 20 hours to obtain a polyamic acid. Next, a dehydration ring-closing agent such as acetic anhydride, pyridine or triethylamine is added to the reaction solution, and the mixture is further added at room temperature for 3 hours.
The polyamide acid is made into polyimide by reacting for ~ 20 hours. Alternatively, the polyamic acid is heated to 180 to 200 ° C., and benzene, toluene, xylene, chlorobenzene,
While adding a hydrocarbon or a chlorinated solvent which can azeotrope with water such as dichlorobenzene and removing the water generated by the cyclization of the amic acid out of the system by azeotropy, the polyamic acid is reacted with the polyimide for 5 to 10 hours to obtain a polyimide. Become The polyimide obtained from these was N-methyl-2-pyrrolidone, N, N-
Dimethylacetamide, dimethylsulfoxide, diglyme, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidin, hexamethylphosphoramide,
It is soluble in m-cresol and the like.

(Gas Separation Membrane and Manufacturing Method Thereof) The third invention of the present application is a gas separation membrane made of the polyimide and a manufacturing method thereof. The polyimide of the present invention may be used alone as a separation membrane, or may be used as a mixture.

The gas separation membrane of the present invention can be produced from the polyimide by various methods. That is, the polyimide represented by the general formula (I) is dissolved in a film-forming solution solvent to form a uniform film-forming solution, which is cast and applied to a suitable support substrate, and then subjected to a heat treatment or a heat treatment under reduced pressure. To evaporate the solvent to form a homogeneous film. Practical gas permeation performance,
In other words, a sufficiently thin film is necessary to obtain a high transmission speed, but from the viewpoint of mechanical strength and prevention of pinholes, the thickness is desirably 0.03 to 20 μm. Therefore, the film forming solution is preferably 20% by weight or less, preferably 10% by weight or less for forming the thin film. As the solvent for the film forming solution, N-methyl-
Organic solvents such as 2-pyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, diglyme, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidine, hexamethylphosphoramide, and m-cresol are preferred. Especially N-methyl-2-pyrrolidone,
N, N-dimethylacetamide and diglyme are preferred.

The support substrate of the gas separation membrane is not particularly limited, and may be, for example, a heat-resistant polymer, glass, metal,
Any known support for a gas separation membrane having a smooth surface made of ceramics or the like may be used.
To form a polyimide film on such a supporting substrate,
For example, a film forming solution is applied to a supporting substrate, and then heated. The heating temperature depends on the solvent for the film-forming solution, but is 80 to 200 ° C, preferably 100 to 150 ° C for the above-mentioned organic solvent. In particular, it is preferable to evaporate most of the solvent in such a temperature range and then elevate the temperature to 200 to 300 ° C. to completely evaporate the solvent.

As another method, water or an organic solvent mixed with the above-mentioned organic solvent after the film-forming solution is applied to the supporting substrate
(Polyimide poor solvent) and then dried at the above temperature to form a heterogeneous film. The membrane shape and membrane form of the polyimide gas separation membrane of the present invention are not particularly limited, and may be a composite membrane. The membrane shape can be a flat membrane or a hollow fiber membrane.

[0026]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following, the film performance is defined as follows.

Gas Permeability Coefficient An index indicating the gas permeation rate through a semipermeable membrane, the unit of which is expressed by the following equation. Barrer = 1 × 10 ⁻¹⁰ cm ³ (STP) cm / cm ²
/ S / cmHg [cm ³ (STP) is the volume of gas permeating at standard temperature and pressure (0 ° C., 1 atm), cm is the thickness of the film, cm ²
Indicates the area of the film, s indicates time, and cmHg indicates pressure. ]

Selectivity The gas selectivity of a semi-permeable membrane is expressed as the ratio of the permeation coefficients measured for individual gases alone on the same membrane. For example, CO ₂ / N ₂
= 50 indicates that the film permeates CO ₂ gas at 50 times the speed of N ₂ gas. The gas separation membrane provided by the present invention has excellent heat resistance, chemical resistance, etc., can be used as a gas separation membrane in a wide range of fields, and has a gas permeation performance and selectivity that are significantly higher than conventional heat-resistant polymer materials. It is excellent. Hereinafter, the present invention will be described in more detail with reference to Examples, but it should not be construed that the invention is limited thereto.

Example 1 (Preparation of polyimide) 4- [4- (4-aminophenyl) buta-1,3- was placed in a 1 L three-necked flask equipped with a dropping funnel.
Diynyl] phenylamine 5.00 g (21.5 mmol
1) 60 g of N, N-dimethylacetamide was taken and dissolved by stirring under an argon gas atmosphere. Remove this flask from 0
After immersion in a 4 ° C. water bath, 9.56 g (21.5 mmol) of 4,4 ′-(hexafluoroisopropylidene) diphthalic dianhydride
l) was added in three portions over 1 hour. After the addition, the flask was returned to room temperature and reacted with stirring for 8 hours to obtain a polyamic acid. 7.69 g of acetic anhydride (7.
5.2 mmol) and 6.96 g (75.2 mm) of pyridine
ol) and reacted at room temperature for 15 hours, and then poured into a water-alcohol mixed solution to obtain a polyimide resin precipitate. It was further washed several times with alcohol and dried.
The obtained yellow flake-form polyimide was soluble in an organic solvent, and the amount was 13.3 g (96.5%). The intrinsic viscosity of the polyimide resin is 1.95 (dL / g) (0.5 g / dL
NMP, 30 ° C.). This polyimide resin has an average degree of polymerization of 131 composed of repeating units having the following structure.
It was confirmed that the polyimide was 0. 1 and 2 show 1H-NMR and FT-IR spectra of this polyimide.

[0030]

Embedded image

The obtained polyimide resin is an organic solvent (N-
Methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphoramide, It could be used as a solvent. It was partially soluble in chloroform and tetrahydrofuran.

(Production of Gas Separation Membrane and Selective Permeability of Gas)
This polyimide resin was dissolved in N-dimethylacetamide at a concentration of 9% by weight, filtered through a stainless filter having a pore size of 5 μm, and defoamed under reduced pressure. This resin solution was applied on a glass plate by casting, and then 80 ° C. × 2 hours, 110 ° C. × 1 hour, 15 ° C.
The solvent was removed at 0 ° C for 1 hour. After peeling from the glass plate, 1
Heat treatment was performed for 24 hours in a 50 ° C. vacuum dryer. Even if the obtained film was folded in two, the film was so strong that no crack was required. Tables 2 and 3 show the permeation coefficient and separation coefficient of each gas measured by measuring the permeation of each gas of nitrogen, carbon dioxide, oxygen and methane alone at 25 ° C. at a pressure difference of 1.0 and 2.94 atm. Was.

Example 2 In Example 1, 5.00 g (21.5 mmol) of 3- [4- (3-aminophenyl) buta-1,3-diynyl] phenylamine was used as a diamine, and 4% was used as an acid dianhydride. , 4 '-(Hexafluoroisopropylidene)
A light yellow polyimide was obtained in exactly the same manner except that 9.56 g (21.5 mmol) of diphthalic dianhydride was used.
The yield was 13.4 g (yield 97.2%). The intrinsic viscosity of this polyimide is 1.62 (dL / g) (0.5 g / d
L NMP, 30 ° C.). This polyimide resin has an average degree of polymerization of 9 composed of repeating units having the following structure.
It was confirmed to be 60 polyimide. 3 and 4 show 1H-NMR and FT-IR spectra of this polyimide.

[0034]

Embedded image

The obtained polyimide resin was treated with an organic solvent (N-
Methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphoramide, chloroform). It could be used as a film solvent. It was partially soluble in tetrahydrofuran.

(Production of gas separation membrane and gas selective permeability)
A film was formed in the same manner as in Example 1. Even if the obtained film was folded in two, the film was so strong that no crack was required. Tables 2 and 3 show the permeation coefficient and separation coefficient of each gas measured by measuring the permeation of each gas of nitrogen, carbon dioxide, oxygen and methane alone at 25 ° C. at a pressure difference of 1.0 and 2.94 atm. Indicated. [Example 3] In Example 1, 4- [4-
5.00 g of (4-amino-3-methylphenyl) buta-1,3-diynyl] -2-methylfelamine (19.2 mmol
l), 8.53 g (19.2 mmol) of 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride as an acid dianhydride
Was used in exactly the same manner as above, except that a light yellow polyimide was obtained. The yield was 10.2 g (89.4% yield).
The intrinsic viscosity of this polyimide is 0.95 (dL / g) (0.5
g / dL NMP, 30 ° C.). In addition, it was confirmed that this polyimide resin was a polyimide having an average degree of polymerization of 640 comprising repeating units having the following structure. Figures 5 and 6
Shows the H-NMR and FT-IR spectra of this polyimide.

Embedded image The obtained polyimide is an organic solvent (N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphoramide , Chloroform). It was partially soluble in tetrahydrofuran. (Production of Gas Separation Membrane) A polyimide membrane was produced by the same method as that of Example 1. Even if the obtained film was folded in two, the film was so strong that no crack was required. Table 2 shows the permeation coefficient and separation coefficient of each gas measured by measuring the permeation of each gas of carbon dioxide, nitrogen, oxygen and methane alone at 25 ° C. with a pressure difference of 1 and 2.94 atm.
3 is shown. Example 4 5- [4- (3-Amino-4-methoxyphenyl) buta-1,3-diynyl] as diamine of Example 1
4.3 g of 2-methoxyphenylamine (14.7 mm
ol), 6.53 g (14.7 m) of 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride as an acid dianhydride
mol) was used to obtain a pale yellow polyimide. The yield was 9.96 g (96.8% yield). The intrinsic viscosity of this polyimide is 0.83 (dL /
g) (0.5 g / dL NMP, 30 ° C.). Also,
It was confirmed that this polyimide resin was a polyimide having an average degree of polymerization of 560, comprising a repeating unit having the following structure. 7 and 8 show the H-NMR and FT of this polyimide.
-IR spectrum was shown.

Embedded image The obtained polyimide is an organic solvent (N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphoramide , Chloroform). It was partially soluble in tetrahydrofuran. (Production of Gas Separation Membrane) A polyimide membrane was produced by the same method as that of Example 1. Even if the obtained film was folded in two, the film was so strong that no crack was required. Table 2 shows the permeation coefficient and separation coefficient of each gas measured by measuring the permeation of each gas of carbon dioxide, nitrogen, oxygen and methane alone at 25 ° C. with a pressure difference of 1 and 2.94 atm.
3 is shown.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

The gas separation membrane of the present invention has excellent heat resistance, chemical resistance, etc., can be used as a gas separation membrane in a wide range of fields, and its gas permeation performance and selectivity are higher than those of conventional heat-resistant polymer materials. It is much better.

[Brief description of the drawings]

[1] ^{1 H-N} of the polyimide obtained in Example 1
It is an MR spectrum.

FIG. 2 is an IR absorption spectrum of the polyimide obtained in Example 1.

FIG. 3 shows ¹ H-N of the polyimide obtained in Example 2.
It is an MR spectrum.

FIG. 4 is an IR absorption spectrum of the polyimide obtained in Example 2.

FIG. 5 shows ¹ H—N of the polyimide obtained in Example 3.
It is an MR spectrum.

FIG. 6 is an IR absorption spectrum of the polyimide obtained in Example 3.

FIG. 7 shows ¹ H-N of the polyimide obtained in Example 4.
It is an MR spectrum.

FIG. 8 is an IR absorption spectrum of the polyimide obtained in Example 4.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D006 GA41 MB04 MB11 MB15 MC58X NA01 NA62 PA04 PB17 PB18 PB19 PB62 PB63 PB64 PB66 PB68 PB70 PC71 4J043 PA01 PA02 PC046 QB15 QB26 QB31 RA34 RA35 SA06 SA42 SA43 SA47 SA52 SA51 SA72 SB01 TA02 TA22 TA47 TA71 TA75 TB01 UA122 UA131 UA132 UA222 UA262 UA662 UA672 UB062 UB081 UB091 UB101 UB122 UB152 UB302 VA021 VA041 VA061 VA081 XA18 YA06 YA08 ZA11 ZA12 ZB13

Claims (3)

[Claims] 1. The following general formula (I): (However, S is a tetravalent organic group, R is a halogen atom, a methyl group, a trifluoromethyl group or a methoxy group. M is 0
It means an integer of ~ 4. Further, n means an integer of 50 to 1800. A polyimide having a repeating structural unit represented by). 2. The following general formula (II): (Where S is a tetravalent organic group) and a tetracarboxylic dianhydride represented by the following formula (III): (Where R is a tetravalent organic group, R is a halogen atom, a methyl group, a trifluoromethyl group or a methoxy group. M is 0
It means an integer of ~ 4. (1) wherein polycondensation is carried out with a diamine having a diacetylene skeleton represented by the following general formula (I): (However, S, R and m are the same as above, and n is 50 to 180
Means an integer of 0. A) a method for producing a polyimide having a repeating structural unit. 3. A gas separation membrane formed of the polyimide according to claim 1.