JPH0459325B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new polymer and a separation membrane using the same, and the first object of the present invention is to use a novel polymer having an alkane unit as a constituent element, or an alkene unit and an alkane unit as constituent elements. A second object of the present invention is to provide a novel polymer material, and a second object of the present invention is to provide a separation membrane that uses such a polymer material for separating or concentrating a specific component in a mixture. An object of the present invention is to provide a gas separation membrane among separation membranes using the polymer material. According to the present invention, the first object is to achieve a weight average molecular weight consisting of 5 to 99 mol% of structural units represented by the following formula (I) and 95 to 1 mol% of structural units represented by the following formula (). Achieved by 10,000 to 2 million random copolymers, (In the above formulas (I) and (), R is a hydrogen atom, a halogen atom or a methyl group,
(R' is an alkyl group or an aryl group having 10 or less carbon atoms which may have a substituent) Furthermore, the second and third purposes are achieved by using separation membranes and gas separation membranes mainly composed of the above polymers. will be achieved. The present invention will be explained in detail below. The polymer of the present invention is a random copolymer having a weight average molecular weight of 10,000 to 2 million, consisting of 5 to 99 mol% of structural units represented by the following formula (I) and 95 to 1 mol% of structural units represented by the following formula (). It is.
Preferably, the structural units of (I) and () are 10 to 90 mol% and 90 to 10 mol%, respectively. In the above formulas (I) and (), R is a hydrogen atom, a halogen atom or a methyl group,
R' is an alkyl group or aryl group having 10 or less carbon atoms which may have a substituent. Examples of substituents on alkyl groups include aryl groups. Specifically, R is a hydrogen atom, a chlorine atom, or a lower alkyl group such as a methyl group, and R' is:
Examples include alkyl groups having up to about 10 carbon atoms, such as secondary or tertiary butyl groups, pentyl groups, hebutyl groups, and phenyl groups. Of course, it may contain structural units other than the structural units of formulas (I) and () above, as long as they are in a small proportion. However, this polymer can be obtained by hydrogenating a polymer obtained from a monomer represented by the following general formula (). R-C≡C-R'...() (Here, R and R' are the above (I) and ()
Specific examples of monomers include secondary or tertiary butylacetylene, 2-octyne, 2-decyne, 2-decyne,
-chloro-1-phenylacetylene, 1-phenyl-1-propyne, and the like. Of course, it may also be a copolymer containing a small proportion of a monomer other than the monomer of formula (). In order to obtain a chain polymer with a weight average molecular weight of 10,000 or more from the monomer of formula () above, molybdenum pentachloride or tungsten hexachloride is used as a main catalyst, and various reducing agents are combined with this as a second component. A catalyst is used. Various organometallic compounds and metal hydrides are used as the reducing agent. Examples of organometallic compounds include those containing boron, aluminum, silicon, tin, lead, arsenic, antimony, and the like. Among these, organic tin compounds such as tetra-n-butyltin and tetraphenyltin are particularly preferred in terms of ease of handling, availability, and effectiveness. Further, as the metal hydride, lithium aluminum hydride, sodium borohydride, sodium hydride, etc. are used. The molar ratio of the monomer to the main catalyst is 100 for the former.
In contrast, the latter range is suitably in the range of 5 to 0.2, and the molar ratio of the reducing agent to the main catalyst is preferably in the range of 0.3 to 3. The catalyst is used in the form of a solution, and the main catalyst and reducing agent are preferably dissolved in a solvent (the same solvent as the polymerization reaction solvent described below is used) and left at 30 to 60°C for 10 to 60 minutes before use. As the solvent for the polymerization reaction, hydrocarbons, halogenated hydrocarbons, etc. are preferable. In particular, hydrocarbons such as benzene, toluene, and cyclohexane are preferred because they are easily available and can achieve high yields in polymerization reactions. The monomer concentration in the polymerization reaction is preferably in the range of 0.1 to 5 mol/mol. The temperature of the polymerization reaction is usually selected from 0 to 60°C, and the reaction time is selected from a range of several tens of minutes to several tens of hours. After the reaction is completed, the reaction system is diluted with the solvent used in the reaction and then poured into a large amount of methanol. Since the resulting polymer precipitates, it is separately dried. By the above method, a novel chain polymer can be obtained in high yield from the monomer of the above formula (), and the weight average molecular weight of the polymer is determined by light scattering method to be 10,000 or more, especially 100,000 to 100,000. It has a molecular weight of 2 million, which is extremely high for an acetylene polymer, and is also characterized by being completely soluble in hydrocarbons such as toluene and cyclohexane. The novel polymer of the present invention is obtained by hydrogenating the polymer thus obtained. Hydrogenation can be carried out in a proportion of 5 to 99 mol%, preferably 10 to 90 mol%, of the unsaturated bonds present in the polymer, and all these hydrogenated compounds are the second object of the present invention. It can be used as a material for separation membranes. For hydrogenation, commonly used means of catalytic hydrogenation treatment can be employed. That is, as the hydrogenation catalyst, a nickel catalyst (for example, Raney nickel), a cobalt, platinum, palladium, ruthenium, rhodium catalyst, or a mixture or alloy catalyst thereof can be used. These catalysts can be used alone, as solid or soluble homogeneous complexes, or supported on carbon, silica, alumina, diatomaceous earth, and the like. In addition, compounds containing nickel, titanium, cobalt, etc. can be added to organometallic compounds (e.g. trialkylaluminum, alkyllithium, etc.)
Hydrogenation may be carried out using a metal complex obtained by reduction with . Molecular hydrogen is usually used as hydrogen, but hydrogen-containing gas can also be used as long as it does not contain substances that poison the catalyst. The hydrogen pressure may be a normal pressure flow or a pressurized system. The temperature is between room temperature and 200°C, preferably below 180°C. The resulting polymer has a weight average molecular weight of 10,000 to 2,000,000, especially 100,000 to 2,000,000, which is extremely high for a polymer made of alkanes and alkenes.
It has the characteristic of being completely soluble in hydrocarbons such as toluene and cyclohexane, and is also heat resistant.
It has properties such as oxidation resistance that are significantly improved compared to alkyne polymers. The polymer thus obtained can be applied to semiconductors, gas adsorbents, separation membranes, photoresists, etc. Next, a separation membrane made of the polymer of the present invention will be explained. The film forming method is not particularly limited. Preferred membrane forming methods include coating a separately formed porous membrane, forming an anisotropic membrane consisting of a dense skin layer and a porous layer, and forming a separately formed thin film with separability into a porous layer. There are two methods: a method in which a polymer solution is superimposed on a film, a method in which a polymer solution is cast on a glass plate, etc., and the solvent is evaporated to form a homogeneous film. The method for coating a porous membrane is to dissolve the above-mentioned novel polymer in an organic solvent, immerse a separately formed porous membrane made of another material in this solution, and then coat the porous membrane with the organic solvent. dry. The organic solvent used when dissolving the polymer to form a film-forming solution is a low boiling point solvent that dissolves the polymer and is relatively easy to desolvent,
There is no particular limitation as long as it does not dissolve the porous membrane that serves as the support. Depending on the type of porous membrane material, for example,
Examples include benzene, toluene, pentane, hexane, hebutane, and tetrahydrofuran. The porous membrane used in the present invention is a membrane that has a sponge-like structure and has open pores on both sides, or a membrane that has a dense layer on one side and open pores on the other side. It is a membrane or a membrane having molecularly microscopic ultra-fine pores, and the permeation rate of nitrogen gas is per unit membrane area (1 cm ² ), unit time (1 second),
Permeation amount per unit pressure difference (1cmHg) is 1×10 ^-4
cm ² /cm ²・sec・cmHg or more. Such a membrane can be made by various methods, but for example, it can be made by adding an organic solvent or additive to a porous membrane material, forming the membrane, and then eluting the organic solvent or additive. . The type of material for the porous membrane is not particularly limited, but
For example, polypropylene, polyvinyl chloride, polystyrene, polyvinyl alcohol, polymethyl methacrylate, polyacrylonitrile, polycarbonate, polyphenylene oxide, polyamide, polysulfone, polyether sulfone, polysulfonamide, polypiperazine, cellulose acetate, cellulose acetate butyrate, Teflon, Examples include vinylidene fluoride, polyvinyltrimethylsilane, and polymers containing a polyamino acid structure. Inorganic materials such as glass can also be used. When the above polymer is dissolved in an organic solvent and coated on a porous membrane, the solution concentration is determined by the molecular weight of the polymer,
Although it varies depending on the molecular weight distribution and type of solvent,
0.1% to 50% by weight, preferably 1% to 10% by weight. If the concentration is less than 0.1% by weight, the thickness of the membrane to be coated will be thinner, and the gas permeation rate will be high, but sufficient separation performance will not be obtained, and if the concentration is higher than 50% by weight, coating will be necessary. As the membrane becomes thicker, the separation performance is improved, but the gas permeation rate becomes lower. Usually the amount of polymer coverage is 1 cm ² of porous membrane area.
The amount is selected to be 0.01 to 10 mg per serving. The thickness of the porous membrane is not particularly limited, but is 10μ.
~100μ is preferred. The method of coating the porous membrane with the novel polymer is not particularly limited, but methods such as immersing the porous membrane in a polymer solution or casting a polymer solution onto the surface of the porous membrane can be used. I can do it. Next, a method for forming an anisotropic film will be described. The anisotropic film can be formed in accordance with the method for forming an anisotropic film of vinyltriorganosilane described in JP-A-46-2093. (1) have a boiling point difference of at least 30°C and have a higher boiling point than the two solvents that serve as solvents for the polymer and the more volatile solvents (hereinafter referred to as light solvents); and a ternary mixture consisting of one type of solvent that is a non-solvent for the polymer,
Pour the solution containing the polymer onto the support (hereinafter, the solvent with lower volatility is referred to as the heavy solvent) (2) remove all or part of the light solvent, and (3) solidify the produced film. A film can be formed by a method comprising: treating with a liquid (non-solvent), and (4) drying the film. Light and heavy solvents are suitably selected from aliphatic and aromatic hydrocarbons such as cyclohexane, benzene and toluene, and halogenated hydrocarbons such as dichloromethane, dichloroethylene, tetrachloroethylene, chloroform, dichlorobenzene and monochlorobenzene. be done. Suitable nonsolvents for the polymer include water, methanol, ethanol, and primary, secondary, and tertiary nonsolvents.
Alcohols such as butanol and ketones such as acetone, methyl ethyl ketone and cyclohexanone are included. The proportions of light solvent, heavy solvent, and non-solvent are such that the polymer is soluble in these ternary mixtures and insoluble (but possibly swellable) in the heavy solvent/non-solvent mixture. There must be. In order to overlay a separately produced thin film with separability on a porous membrane, first, a polymer solution is spread on the water surface. The polymer solution spreads thinly on the water surface, and when the solvent evaporates, an extremely thin film of polymer is formed. Ultra-thin films usually exhibit interference stripes;
Thicknesses of less than 1μ are easily obtained. This thin film is collected and stacked on a porous support membrane,
A composite membrane may be used. A method for obtaining a homogeneous film is to form a film by casting a solution of a polymer dissolved in a good solvent onto a flat surface such as a glass plate. When coating on a porous membrane or forming an anisotropic membrane, (1) The shape of the membrane may be hollow fiber, tube, spiral, or flat plate. It can also be used in (When coating on a porous membrane, the shape of the porous membrane can be selected. (2) The membrane can be further heat-treated after the membrane is formed. (3) Plasma polymerization is applied to the surface of the membrane of the present invention. (4) The permeation rate can be improved by mixing a polymer having a polysiloxane bond with the new polymer of the membrane material.The membrane of the present invention can be used for gases, especially oxygen, nitrogen, carbon dioxide,
It can be used to separate gas mixtures containing at least one of the following gases: carbon monoxide, hydrogen, helium, methane, argon. For example, separation of nitrogen and oxygen in the production of oxygen-enriched air, separation of methane and helium in the recovery of helium from natural gas, separation of argon and hydrogen, and methane in the recovery of hydrogen from hydrogenation reaction exhaust gas. and hydrogen, separation of nitrogen and hydrogen, separation of carbon monoxide and hydrogen in recovery of hydrogen from cracking gas,
It can be applied to separation of carbon dioxide and nitrogen in the recovery of carbon dioxide from combustion gas. Next, the content of the present invention will be explained with reference to Examples, but the content of the present invention is not limited only to the Examples. Production example 1 Toluene 1 sufficiently purified under dry nitrogen atmosphere
30 mmol of molybdenum pentachloride and 30 mmol of tetraphenyltin were added thereto, and the mixture was heated at 30° C. for about 15 minutes. 0.50 mol of 2-octyne was added to the obtained catalyst solution and polymerized at 30°C for 24 hours. After the reaction was completed, the mixture was dissolved in toluene and poured into a large amount of methanol to precipitate the resulting polymer, which was separately dried. The amount of methanol-insoluble polymer produced was 70% of the amount of 2-octyne charged. The weight average molecular weight of the produced polymer was approximately 500,000 according to a light scattering method, and the intrinsic viscosity measured at 30° C. in toluene was 2.40 dl/g. The resulting polymer is a white solid, completely soluble in benzene, toluene, cyclohexane, n-hexane, and tetrahedrofuran, partially soluble in carbon tetrachloride, chloroform, and diethyl ether, and ethylene dichloride, acetone, and acetic acid. It was insoluble in ethyl, nitrobenzene, and acetonitrile. The analytical values of the produced polymer were as follows. Elemental analysis value [as ( _C8H14 )n]: Calculated value _, C, 87.19; H, 12.81; Actual value, C, 86.67; H, 12.91; Infrared absorption spectrum; 3000-2850 (s), 1650-1580 (w) 1470 (s), 1370 (m), 1260 (w), 1100 (m) 1010 (m), 800 (w), 720 (m), NMR spectrum (100MH _g , in heavy benzene)
The proton signal was as follows.

[Formula] 3.8 to 2.2 ppm C Methylene signal at position ⁴ 2.1 to 1.9 ppm C Signal of methyl at position ¹ 1.7 to 1.2 ppm C Signal of methylene at position ⁵⁶⁷ 1.2 to 0.8 ppm C Signal of methyl at position ⁸ Example 1 Poly Hydrogenation reaction of (2-octyne) In a 200ml autoclave, 1.6g of the poly(2-octyne) obtained in Production Example 1 and the ruthenium catalyst supported on carbon were added.
0.8g, normal hebutane 66.2g, isopropyl alcohol 3.8g, 150℃, hydrogen pressure 57Kg/
The reaction was carried out at cm ² G for 0.5 hours. After the reaction, the catalyst was removed by filtration, and about 10 times the volume of methyl alcohol was added to the solution to precipitate the polymer. Filtration and washing with methyl alcohol were repeated to obtain a hydrogenated product. This product was measured by gel permeability chromatography (hereinafter abbreviated as GPC). The GPC measurement conditions are as follows: Toyo Soda RI-8 detector
Type, column TSK-G 5000H, 4000H, 3000H,
2000H, solvent tetrahydrofuran, flow rate 1ml/
min, 45°C, and was calibrated using monodisperse polystyrene manufactured by Plessyer Chemical (USA), and all values are converted to polystyrene. The GPC measurement results of the product showed that the number average molecular weight and weight average molecular weight in terms of polystyrene were 14,000 and 118,000, respectively, and Mw/MN was 8.4. The elemental analysis value and infrared spectrum of this product showed no significant difference from the unhydrogenated product of Production Example 1. A change in signal was observed in the Broton NMR spectrum. In other words, the methylene signal at C ⁴ position from 3.8 to 2.2 ppm decreases The methyl signal at C ¹ position from 2.1 to 1.9 ppm decreases The methylene signal at C ^{5 to 7} from 1.7 to 1.2 ppm increases. When quantifying the change in this signal, The hydrogenation rate was approximately 13%. This product has the formula

Represented by [formula] 87 mol% structural unit, formula

It is a polymer having 13 mol% of the structural unit represented by the formula. The obtained poly(2-octyne) hydrogenated product was dissolved in toluene, cast onto a glass plate, and after drying, a 30μ homogeneous film was obtained. For comparison, a 30μ homogeneous film was obtained using the unhydrogenated product in the same manner. Put the obtained film into a hot air dryer and set the temperature
After hot air treatment at 100°C for 5 minutes, 15 minutes, and 30 minutes, the sample was taken out, its infrared absorption spectrum was measured, and thermal stability was checked by the increase in absorption of carbonyl groups around 1700 cm ^-1 . . Unhydrated additive...An increase in absorption was observed after 15 minutes of heat treatment. Hydrogenated substances...No increase in absorption was observed even after 30 minutes of heat treatment. Example 2 The hydrogenated poly-2-octyne obtained in Production Example 1 above was dissolved in toluene to make a 10% by weight solution. After filtering and defoaming, this solution was cast onto a glass plate to form a 500μ A doctor knife was run at 1 m/min, and after air drying, the film was dried under reduced pressure at room temperature for 12 hours to obtain a homogeneous film with a thickness of 30 μm. This homogeneous membrane was attached to a permeation test device, and the permeation characteristics of various gases were measured. The measuring device used was an ultraviolet device (Model 52, manufactured by Amicon, USA). After the membrane was attached, a specified gas was applied to the top surface of the membrane at a pressure of 1.0 kg/cm ² G. Connect the bottom surface of the membrane to a gas filter and measure the amount of gas that permeates through the membrane over a certain period of time at 25°C to determine gas permeability. The results are shown in Table 1 below. The unit of gas permeability coefficient for various gases is CC (STP)/cm ² sec cmHg.

[Table] Example 3 The poly(2-octyne) water additive obtained in Production Example 1 was dissolved in toluene, adjusted to a concentration of 5 wt%, and kept at 34°C. The polymer solution is filled in a container in advance,
Add one drop with a micropipette to water maintained at 12°C. The average weight of the droplets at this time was 12.8 mg. The added droplets immediately spread on the water surface, resulting in an extremely thin circular film. The film area at this time was 14 cm ² , and the film thickness calculated from this using the gravimetric method was
It is 0.5μ. The ultrathin membrane obtained here was taken out onto a porous membrane to produce a composite membrane. The amount of gas permeation through this composite membrane was measured in the same manner as in Example 2.
The results are shown in Table 2. The gas permeability of the polysulfone porous membrane used at this time was as follows. Gas permeability (CC/cm ²・sec・cmHg) N ₂ = 5.5×10 ^-4 , O ₂ = 5.1
×10 ^-4 , gas permeability ratio; (O ₂ /N ₂ ) = 0.92.

[Table] Production Example 2 A polymer of 2-decyne was obtained by carrying out the same operation as in Production Example 1 except that 2-decyne was used instead of 2-octyne as a monomer. Elemental analysis value [as (C ₁₀ H ₁₈ )n]: Calculated value, C, 86.88; H, 13.12 Actual value, C, 86.51; H, 12.98 Infrared spectrum: 3000-2850 (s), 1650-1580
(w), 1470 (s), 1370 (m), 1260 (w) 1100 (m
),
1030-1010 (m), 800 (w), 720 (m) Weight average molecular weight: 250,000 (by light scattering method) NMR spectrum (100MHz in heavy benzene,
H signal): 3.8-2.2ppm C Methylene signal at position ⁴ (minor) 2.1-1.9ppm C Methyl signal at position ¹ (small) 1.7-1.2ppm C Methylene signal at position ^5-8 (large) 1.2-0.8ppm C Methyl signal at position ¹⁰ (Middle) Example 4 In Example 1, poly(2-
The same procedure was performed except that poly(2-decyne) was used instead of poly(2-decyne).
A new polymer which is a hydrogenated product of The weight average molecular weight (by light scattering method) was 100,000. There was almost no difference in the elemental analysis values and infrared spectrum from the unhydrogenated product of Production Example 2. The NMR signal was almost the same as in Production Example 2, but the hydrogenation rate was determined from the signal intensity in the same manner as in Example 1 and was approximately 10%. Example 5 The same procedure as in Example 2 was carried out except that a hydrogenated product of poly(2-decyne) was used instead of a hydrogenated product of poly(2-octyne). The film thickness was 28μ. The results are shown in Table 1. Example 6 The same procedure as in Example 3 was carried out except that a hydrogenated product of poly(2-decyne) was used instead of a hydrogenated product of poly(2-octyne). However, the water temperature is 10℃, the number of drops is 3, and the membrane area is
9.4cm ² , the porous membrane used is Millipore filter
VSWP (manufactured by Nippon Millipore Limited). Table 2 shows the measurement results of the gas permeation amount of the composite membrane. In addition, the Millipore filter used at this time
The gas permeation performance of VSWP was as follows. Gas permeability (cc/ ^cm2・sec・cmHg) _N2 =1.9× ^10-2 ,
O ₂ = 1.7×10 ⁻² gas permeability ratio (O ₂ /N ₂ ) = 0.92.

Claims (1)

[Scope of Claims] 1 5 to 99 mol% of structural units represented by the following formula (I) and 95 to 1 structural units represented by the following formula ()
A random copolymer with a weight average molecular weight of 10,000 to 2,000,000, consisting of mol%. (In the above formulas (I) and (), R is a hydrogen atom, a halogen atom, or a methyl group,
R' is an alkyl group or aryl group having 10 or less carbon atoms which may have a substituent. ) 2 5 to 99 mol% of structural units represented by the following formula (I) and 95 to 1 structural units represented by the following formula ()
A separation membrane based on a random copolymer with a weight average molecular weight of 10,000 to 2,000,000. (In the above formulas (I) and (), R is a hydrogen atom, a halogen atom or a methyl group,
3. The separation membrane according to claim 2, which is a gas separation membrane.