JPH06319970A - Gas separation membrane - Google Patents

Abstract

PURPOSE:To obtain a gas separation membrane with excellent stability with the lapse of time by using a material consisting of trimethylsilyldiphenylacetylene polymer and with an oxygen permeability const. of a predetermined value or larger under a specified condition. CONSTITUTION:A gas separation membrane is formed of trimethylsilyldiphenylacetylene polymer. In addition, the obtd. gas separation membrane exhibits a performance wherein between oxygen permeability const. I and II respectively measured after 100 and 500 hours had passed under vacuum at 80 deg.C immediately after preparation of the gas separation membrane, II/I is at least 0.7 (the measuring condition of the oxygen permeability const.: 35 deg.C), pref. 0.95-0.72. A gas separation membrane with excellent stability with the lapse of time can be obtd. thereby.

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 having a small rate of change in oxygen permeability coefficient.

[0002]

2. Description of the Related Art In recent years, attention has been paid to a gas separation membrane which selectively separates a gas using a polymer membrane. For example, an oxygen-enriched membrane which can obtain a high concentration of oxygen gas from air is used for medical purposes. It is expected to be used for combustion. Polymers forming gas separation membranes have been actively developed, and among them, trimethylsilyldiphenylacetylene polymers have been attracting attention because of their high oxygen permeability coefficient and separation coefficient. However, actually, when such a trimethylsilyldiphenylacetylene polymer is used as a gas separation membrane, there is a problem that the stability with time is poor.

[0003]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas separation membrane excellent in stability over time.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention comprises a trimethylsilyldiphenylacetylene polymer, which is used immediately after formation of a gas separation membrane.
The oxygen permeability coefficient at 80 ° C. and 500 hours under vacuum should be 0.7 or more with respect to the oxygen permeability coefficient at 100 ° C. and vacuum at 100 hours (measurement condition of oxygen permeability coefficient: 3
A gas separation membrane characterized by 5 ° C) is provided.

The polymer forming the gas separation membrane of the present invention is a trimethylsilyldiphenylacetylene polymer. The trimethylsilyl group may be in any of the o-position, m-position and p-position, but among them, the p-position is preferable. The specific viscosity (η _sp ) of a polymer toluene solution having a concentration of 1 gram / liter at 30 ° C. using a Ubbelohde viscometer for such trimethylsilyldiphenylacetylene polymer is 0.2 to 3.
0, preferably 0.5 to 3.0, more preferably 1.
It is in the range of 0 to 3.0.

The trimethylsilyldiphenylacetylene polymer having the above-mentioned specific viscosity is present in the presence of a catalyst comprising a halide of a transition metal of Group V of the periodic table and an organometallic compound having a reducing property for the halide and a diacetylene compound. It is obtained by polymerizing 1-trimethylsilylphenyl-2-phenylacetylene. The halide of the transition metal of Group V of the periodic table is a halide such as niobium or tantalum, for example, niobium pentachloride,
Examples thereof include niobium pentabromide, tantalum pentachloride and tantalum pentabromide. You may use these compounds as a mixture of 2 or more types.

Examples of the organometallic compound having a reducing property with respect to the halide include compounds containing a metal such as aluminum, silicon, tin, antimony, bismuth, boron and lithium. For example, trimethylaluminum, triethylaluminum, Examples thereof include monochlorodiethyl aluminum, dichloroethyl aluminum, triethylsilane, triphenylsilane, tetra-n-butyltin, tetramethyltin, tetraphenyltin, triphenylantimony, triphenylbismuth and butyllithium.

The diacetylene compound is 1,3-butadiyne which may have a substituent. As the substituent, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, a hexyl group, a nonyl group or a decyl group; a cycloalkyl group such as a cyclopentyl group or a cyclohexyl group; a phenyl group, a tolyl group or the like Aryl group;
Haloalkyl groups such as chloromethyl group, bromomethyl group, 1-chloro-1-ethyl group, 2-chloro-1-ethyl group; substituted silyl groups such as trimethylsilyl group, dimethylethylsilyl group, dimethylphenylsilyl group, triphenylsilyl group Groups, etc. As the substituent, an aryl group is preferable, and a disubstituted group is particularly preferable.

The amount of the halide of the transition metal of Group V of the periodic table is usually 0.001-1 mol per mol of 1-trimethylsilylphenyl-2-phenylacetylene,
It is preferably in the range of 0.01 to 0.2 mol. The amount of the organometallic compound having a reducing property with respect to the halide of the transition metal of Group V of the periodic table is usually 0.01 to 10 mol, relative to 1 mol of the halide of the transition metal of Group V of the periodic table, It is preferably in the range of 0.1 to 5 mol. The amount of the diacetylene compound used is usually in the range of 0.01 to 10 mol, preferably 0.1 to 5 mol, based on 1 mol of the halide of the Group V transition metal of the periodic table.

Polymerization is usually carried out using a solvent under an atmosphere of an inert gas such as nitrogen. As the solvent, benzene,
Aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as carbon tetrachloride, 1,2-dichloroethane, chlorobenzene and bromobenzene; alicyclic hydrocarbons such as cyclohexane and cyclohexene, and these Mixtures of two or more may be mentioned. The amount of the solvent used is such that the concentration of 1-trimethylsilylphenyl-2-phenylacetylene in the solvent is usually 0.01 to 1
It is appropriately selected within the range of mol / liter. The polymerization temperature can be arbitrarily changed from room temperature to the boiling point of the solvent, but is usually 0 to + 150 ° C. The polymerization time cannot be generally specified depending on the polymerization temperature, but it is usually several hours to several tens hours.

The trimethylsilylphenyldiphenylacetylene polymer thus obtained has a specific viscosity (η _sp ) of 0.2 to 3.0 in a polymer toluene solution having a concentration of 1 gram / liter at 30 ° C. using an Ubbelohde viscometer.
It is a polymer in the range of. The gas separation membrane of the present invention is formed from such polymers. The structure of the membrane may be either a single membrane of polymer alone or a composite membrane of a polymer membrane and a support. The shape of the gas separation membrane is not particularly limited, and may be a sheet shape, a plate shape, a tube shape, a hollow fiber shape, or the like, and is appropriately selected according to the purpose of use and the application. In order to give a sufficient gas permeation amount as a gas separation membrane and to have practical strength, the thickness of the polymer membrane portion is usually 0.01.
To 100 μm, preferably 0.05 to 50 μm.

Examples of the support include non-woven fabric, woven fabric, porous body and the like. Examples of the porous body include a porous polypropylene film, a porous polyethylene film, a porous polysulfone film, a porous cellulose acetate film, a porous tetrafluoroethylene film, and a porous polyimide film. The method for producing the film is not particularly limited.For example, the polymer is dissolved in an organic solvent such as toluene, benzene, carbon tetrachloride, tetrahydrofuran, or cyclohexane to obtain a polymer solution, which is spread on a metal, a glass plate, or the surface of water. After that, a method of evaporating the solvent,
The composite membrane can be obtained by, for example, immersing the porous body in a polymer solution and then pulling it up, coating the porous body with the solution, and drying.

[0013]

The gas separation membrane thus obtained has an oxygen permeation coefficient (I) measured at 80 ° C. immediately after the gas separation membrane is formed and after 100 hours under vacuum, and at 80 ° C. immediately after the gas separation membrane is formed at the vacuum. The oxygen permeation coefficient (II) measured under the elapse of 500 hours means that (II) / (I) is 0.7 or more (measuring condition of oxygen permeation coefficient: 35 ° C.), preferably 0.
The relationship is 95 to 0.72, and is superior in stability over time as compared with the conventional gas separation membrane.

[0014]

EXAMPLES The present invention will be described in more detail with reference to the following examples. Parts and% in the examples and comparative examples are based on weight unless otherwise specified. Example 1 4.0 grams of p-trimethylsilyldiphenylacetylene, 343 tantalum pentachloride in a reactor under a dry nitrogen atmosphere.
Milligrams, 660 milligrams of tetra-n-butyltin, and 40 milligrams of 1,4-diphenylbutadiyne were added and polymerized at 80 ° C. for 12 hours. Next, the reaction solution was cooled to room temperature and poured into a large amount of methanol to precipitate the produced polymer, which was filtered and dried. The yield of the polymer calculated from the yield of the polymer with respect to the charged amount of the monomer is 80%.
Met. The specific viscosity (η _sp ) of the polymer toluene solution having a concentration of 1 gram / liter was measured at 30 ° C. using a Ubbelohde viscometer to measure 3.0.
Met.

0.15 g of the obtained p-trimethylsilyldiphenylacetylene polymer was dissolved in 20 ml of toluene and cast to form a film having a diameter of 90 mm and a thickness of 20 to 30 μm. This film was left under vacuum at 80 ° C to obtain an oxygen permeability coefficient (cm ³ (STP) · cm / c
The change with time of m ² · sec · cmHg) was measured. The oxygen permeation coefficient measurement temperature was 35 ° C. Oxygen permeation coefficient is 5.5 x 1 after 100 hours have passed since the gas separation membrane was created.
O- ⁸ , oxygen permeability coefficient after 500 hours is 4.3 x 1
^0-8 , and the oxygen permeation coefficient after 500 hours was 0.78 with respect to the oxygen permeation coefficient after 100 hours.

Example 2 Polymerization was carried out according to Example 1 except that 64 mg of 1,4-diphenylbutadiyne was used. The yield of the polymer calculated from the yield of the polymer with respect to the charged amount of the monomer was 78%. Further, the specific viscosity (η _sp ) of the polymer toluene solution having a concentration of 1 gram / liter was measured at 30 ° C. using a Ubbelohde viscometer and found to be 2.4. The obtained p-trimethylsilyldiphenylacetylene polymer was operated in the same manner as in Example 1 to form a film. This film is left under vacuum at 80 ° C,
Oxygen permeability coefficient (cm ³ (STP) · cm / cm ² · sec
-Change in cmHg) with time was measured. The oxygen permeation coefficient measurement temperature was 35 ° C. From the time of creating the gas separation membrane 10
Oxygen permeability coefficient at the time of 0 hours is 5.1 × 10 ^-8 , 50
The oxygen permeability coefficient at the time of 0 hours is 4.3 × 10 ⁻⁸ ,
The oxygen permeability coefficient after 500 hours was 0.84 with respect to the oxygen permeability coefficient after 100 hours.

Example 3 Polymerization was carried out in the same manner as in Example 1 except that 128 mg of 1,4-diphenylbutadiyne was used. The yield of the polymer calculated from the yield of the polymer with respect to the charged amount of the monomer was 72%. Further, the specific viscosity (η _sp ) of the polymer toluene solution having a concentration of 1 gram / liter was measured at 30 ° C. using a Ubbelohde viscometer and found to be 1.1. The obtained p-trimethylsilyldiphenylacetylene polymer was operated in the same manner as in Example 1 to form a film. This film was left under vacuum at 80 ° C to obtain an oxygen permeability coefficient (cm ³ (STP) · cm · cm ² · s.
The change in ec · cmHg) with time was measured. The oxygen permeation coefficient measurement temperature was 35 ° C. The oxygen permeation coefficient at the time of 100 hours from the time of forming the gas separation membrane is 4.0 × 10 ^-8 ,
The oxygen transmission coefficient after 500 hours was 3.4 × 10 ⁻⁸ , and the oxygen transmission coefficient after 500 hours was 0.85 with respect to the oxygen transmission coefficient after 100 hours.

Comparative Example 1 Polymerization was carried out according to Example 1 except that 1,4-diphenylbutadiyne was not used. The polymer yield calculated from the polymer yield relative to the charged amount of monomer is 86%.
Met. The specific viscosity (η _sp ) of a polymer toluene solution having a concentration of 1 gram / liter was measured at 30 ° C. using a Ubbelohde viscometer for the polymer, and it was 8.7.
Met. The obtained p-trimethylsilyldiphenylacetylene polymer was operated in the same manner as in Example 1 to form a film. This film is left under vacuum at 80 ° C. and the oxygen permeability coefficient (cm ³ (STP) · cm / cm ² · sec · cmHg)
Was measured over time. Oxygen permeability coefficient measurement temperature is 3
It was 5 ° C. The oxygen permeation coefficient of 100 hours after the gas separation membrane was formed was 7.8 × 10 ^-8 , and the oxygen permeation coefficient of 500 hours was 4.2 × 10 ^-8. The oxygen permeability coefficient after 500 hours with respect to the coefficient was 0.54.

Claims (1)

[Claims] 1. A composition comprising a trimethylsilyldiphenylacetylene polymer, which has an oxygen permeability coefficient of 80 relative to an oxygen permeability coefficient of 100 hours under vacuum at 80 ° C. immediately after formation of a gas separation membrane.
Oxygen permeability coefficient is 0.7 after 500 hours under vacuum at ℃
A gas separation membrane characterized by the above (measurement condition of oxygen permeability coefficient: 35 ° C.).