JPH0698278B2 - Polymer film for oxygen enrichment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polymer film for oxygen enrichment, and more specifically, it contains a specific metal complex capable of reversibly adsorbing and desorbing oxygen in a dispersed state. The present invention relates to a polymer film for oxygen enrichment made of a high molecular polymer.

[Prior Art] Oxygen is one of the most widely used chemical substances industrially in connection with the production of metals such as steel, glass production, chemical oxidation treatment, combustion treatment, and wastewater treatment. In addition, it is an extremely versatile substance for medical use such as oxygen inhalation therapy for patients with lung diseases. Development of such a process for concentrating oxygen from air with low energy is an extremely important and spillover effect. As a method for concentrating oxygen from air, a cryogenic method and an adsorption method are industrially carried out, but it is considered that the membrane separation method will be effective from the viewpoint of energy saving in the future.

Thus, the main point of the membrane separation method is to develop a membrane material capable of selectively and efficiently permeating oxygen as compared with nitrogen in the air. Currently, as a membrane (oxygen-enriched membrane) capable of permeating and concentrating oxygen from air, a silicone membrane, a silicone-polycarbonate membrane, a polyolefin membrane, etc. are used, and some of them have been put into practical use. In these membranes, although the oxygen permeation selectivity (ratio of oxygen permeation coefficient / nitrogen permeation coefficient, α) is not as high as about 2, the permeation coefficient is large (10 ⁻⁸ [cm ³ (STP)
・ Cm / cm ²・ sec ・ cmHg]), by incorporating modules and multi-stage processes, 30-40%
Obtaining oxygen enriched air with oxygen concentration.

[Problems to be Solved by the Invention] In order to obtain highly oxygen-rich air that is industrially useful with a single-stage membrane permeation, it is essential that the separation membrane have α of 10 or more.

Factors that increase α of the film include increasing the solubility of oxygen in the film as compared with nitrogen and increasing the diffusivity of oxygen in the film as compared with nitrogen. However, since there is no difference in the solubility of oxygen and nitrogen in the organic solvent, it is extremely difficult to specify the former factor so that it can be easily inferred. Regarding the latter factor as well, there is almost no difference in the van der Waals radii of both gas molecules, and it is generally impossible to enhance the diffusivity of oxygen alone.

Therefore, no oxygen-enriched film having the above target α value has hitherto been obtained even if the substance forming the polymer film or the method of forming the film is changed, and a film material based on an essentially new concept is expected. That is why it is done.

On the other hand, it is known that a specific metal complex such as a cobalt Schiff base (a complex composed of a conjugated ligand and a low oxidation number metal ion) can reversibly adsorb and desorb oxygen molecules. Therefore, an attempt has been reported to prepare a film impregnated with a high boiling point solvent containing these metal complexes dissolved therein and to realize oxygen enrichment through the liquid film. But in this case,
Since it is a liquid film, it is extremely fragile and the operation becomes very complicated, and many problems such as evaporation of the solvent forming the liquid film over time remain unsolved.

In addition, recently, a film made of a vinyl polymer which has a unit containing a cobalt-salen group bonded to a polymer chain to serve as a cobalt-salen group has been proposed as a solution to the above problems. See JP-A-60-222128.

[Means for Solving Problems] The present inventor has continuously synthesized metal complexes capable of rapidly and reversibly adsorbing and desorbing oxygen molecules. As a result, we have clarified the requirement for a metal complex that can selectively and rapidly and reversibly adsorb and desorb oxygen molecules even in the solid phase of a high-molecular polymer, and succeeded in its new synthesis.

Furthermore, as a result of earnest studies based on the above findings, the present inventor succeeded in producing a high molecular polymer film containing these metal complexes, and using these films, a high oxygen content from a low oxygen content gas was used. It was found that the contained gas can be collected. That is,
As a metal complex capable of reversibly adsorbing and desorbing oxygen, there is generally a complex composed of a metal ion having a low oxidation number and a donor ligand, such as cobalt (II) tetraphenylporphyrin and iron (II) protoporphyrin IX. Examples of the complex include copper (I) phthalocyanine and cobalt (II) acetylacetone, and complexes having a nitrogen-containing compound such as imidazole or pyridine as an axial ligand.
In particular, in the present invention, meso-tetra (α, α, α,
It was found that a film obtained by dispersing a metal complex of a porphyrin compound such as an imidazole compound complex of α-o-pivalamidophenyl) porphinatocobalt (II) in a polymer is effective as an oxygen-enriched film. Was issued.

Thus, the present invention has been completed based on the above findings, and newly provides an oxygen-enriched polymer film comprising a high-molecular polymer containing a metal complex of a porphyrin compound dispersed therein. To do.

The oxygen-enriched film of the present invention is much more excellent in handling strength than a conventional liquid film containing a metal complex, and is also excellent in durability without change over time. Moreover, it is possible to achieve the above α value of 10 or more as an oxygen-enriched film.
Incidentally, in the case of a cobalt-salen type metal complex such as described in JP-A-60-222128, for example, N, N'-bis (salicylidene) ethylenediaminecobalt (II), this is a polymer. Even if the polymer is dispersed and mixed in a polymer, for example, a polymer such as vinyl pyridine or vinyl imidazole, the above α value is about 5 to 6, and it is difficult to achieve the target value.

In the present invention, various examples of the metal complex of the porphyrin compound are exemplified, and a preferable specific example thereof is meso-tetra (α, α, α, α-o-pivalamidophenyl) porphinatocobalt (II). To be These specific metal complexes have 1-methylimidazole, 1,2 as the axial ligand.
-It may have an imidazole compound such as dimethylimidazole. In addition, the ratio of the metal ion constituting the complex to the axial ligand is appropriately in the range of 1 to 100.

In the present invention, the high molecular polymer which comprises the above-mentioned specific metal complex in a dispersed state to form a film is not particularly limited as long as it is a polymer that can include a certain amount or more of the metal complex after film formation. It can be exemplified, and examples thereof include a wide range of silicone resins, polystyrene, polyacrylonitrile and the like. Particularly, as the high molecular weight polymer effective in the present invention, a polymer or copolymer of alkyl acrylate or alkyl methacrylate (alkyl having 1 to 12 carbon atoms) is exemplified.

The method for producing the oxygen-enriched film of the present invention is not particularly limited, but a case where the specific metal complex (A), the axial ligand (B) made of an imidazole compound and the high molecular polymer (C) are used as raw materials As an example, it is as follows. That is, (A), (B) and (C) are each uniformly dissolved in an organic solvent, sufficiently deoxygenated, and then mixed to form a metal complex-containing film by a solvent casting method. in this case,
The content ratio of (A) is appropriately selected from the range of about 1 to 50% by weight. It is desirable that the film is sufficiently deoxidized before being formed. The oxygen-enriched film of the present invention can also be used as a composite film in which a specific metal complex-containing film is superposed with another polymer film. In this way, advantages such as good operation under a wide supply oxygen partial pressure condition and reduction in film thickness can be obtained. For example, a composite film can be formed by casting an organic solution of a specific metal complex-containing polymer on a hydroxyethyl acrylate-hydroxyethyl methacrylate copolymer film. Needless to say, a specific metal complex-containing polymer film can be supported on a support such as a porous film, or the porous film can be impregnated and supported with a specific metal complex-containing polymer to form a composite film.

The thickness of the oxygen-enriched film of the present invention is not particularly limited, but is usually selected from the range of about 1 to 100 μm, and can be appropriately selected according to the aspect of the above composite film and the like. By using such a membrane of the present invention, it becomes possible to enrich oxygen with high selectivity of α value of 10 or more, and for example, it becomes possible to obtain air having an oxygen concentration of 70% or more by one-step concentration. The gas permeation measurement using the oxygen-enriched membrane may be performed using a normal low vacuum gas permeation measurement device or a normal thickness gas permeation measurement device.

[Examples] Next, examples of the present invention will be described more specifically, but it goes without saying that the present invention is not limited to these examples.

Example 1 A toluene solution containing 24.0 mg of meso-tetra (α, α, α, α-o-pivalamidophenyl) porphinatocobalt (II) (hereinafter abbreviated as MTPFC) and 1-methylimidazole (2.2 ×). Mixture with toluene solution of 10 ^-2 mol) 15m
15 ml of a toluene solution containing 1 and 376.0 mg of polybutyl methacrylate were bubbled with nitrogen for 0.5 hours, respectively, and then both solutions were simultaneously deaerated under vacuum using a three-way tube.

After thoroughly degassing, mix both solutions above, and the total solution volume is 15 ml.
The solvent was removed under vacuum until. After that, the solution under vacuum is set in a dry box, the inside of the dry box is replaced with nitrogen several times, the solution under vacuum is leaked, and the solution is cast on a 7 cm x 7 cm polytetrafluoroethylene plate. . Next, the pressure in the dry box is sequentially increased to 50 cmH.
g, 30 cmHg, 15 cmHg, 10 cmHg, 5 cmHg, 0 for each.
After being left for 5 hours, it was left under vacuum for 24 hours to form a film. As a result, a transparent polymer film containing MTPFC at 6.0% by weight and having a thickness of 50 to 60 μm was obtained. The reversible adsorption / desorption of oxygen to the MTPFC / 1-methylimidazole complex in this film can be confirmed from the visible spectrum change (oxygenation: 545 nm, deoxygenation: 527 nm).

The air permeability of the obtained metal complex-containing polymer film was measured by a low vacuum method at a supply pressure of 50 nmHg. As a result, the permeability coefficient was 3.2 × 10 ^-9 cm ³ (STP) · cm / cm ² · sec · cmHg. And oxygen permeated efficiently at α = 16.

Example 2 In the same manner as in Example 1, except that 1,2-dimethylimidazole was used as the axial ligand instead of 1-methylimidazole, the same procedure as in Example 1 was carried out. It was created. The obtained membrane was subjected to the same permeation measurement as in Example 1, and as a result, the permeation coefficient was 3.2 × 10 ⁻⁹ cm ^3.
(STP) · cm / cm ² · sec · cmHg, and oxygen efficiently permeated at α = 11.

Example 3 In the same manner as in Example 1, the operation before casting on a polytetrafluoroethylene plate was performed. The resulting solution is cast onto a hydroxyethyl methacrylate-hydroxyethyl acrylate copolymer film (film thickness 50 to 60 μm) which is previously formed on a polytetrafluoroethylene plate.
Thereafter, in the same manner as in Example 1, a composite film in which the metal complex-containing film containing MTPFC in an amount of about 6.0% by weight and having a thickness of 50 to 60 μm and the acrylate copolymer film were superposed was obtained. With respect to the obtained film, the metal complex-containing film surface was directed to the secondary side (vacuum side) and the permeation was measured by the low vacuum method at a supply pressure of 151 mmHg. As a result, the permeation coefficient was 1.2 × 10 ^-9 cm ³ (STP ) ・ Cm / cm ²・ s
It was ec · cmHg, and oxygen permeated efficiently at α = 12.

Example 4 In the same manner as in Example 1, except that polyoctyl acrylate was used instead of polybutyl methacrylate, a metal complex-containing polymer film containing about 6.0% by weight of MTPFC and having a thickness of 50 to 60 μm was prepared. Example 1 of the obtained membrane
As a result of performing the same transmission measurement, the transmission coefficient was 4.5 × 10
^{It was −9} cm ³ (STP) · cm / cm ² · sec · cmHg, and α = 9.

Reference Example 1 N, N'-bis (salicylidene) ethylenediaminecobalt (II) (hereinafter abbreviated as cobalt-salen) 50.0
A chloroform solution (15 ml) containing mg and a chloroform solution (15 ml) containing 370.0 mg of octylmethacrylate-vinylpyridine copolymer were bubbled with nitrogen for 0.5 hours, and then vacuum degassing was performed to bring the total amount of the solution to 15 ml. The solvent was removed until it became, and it was set in a dry box. Next, after the inside of the dry box was replaced with nitrogen several times, the solution under vacuum was leaked and cast on a polytetrafluoroethylene plate of 7 cm × 7 cm. After that, in the same manner as in Example 1, about
A 50-60 μm thick film containing 12.0 wt% cobalt-salen was prepared.

The obtained membrane was subjected to the same permeation measurement as in Example 1, and as a result, the permeation coefficient was 2.5 × 10 ⁻⁹ cm ³ (STP) · cm / cm ² · sec.
-CmHg and α = 6.

Reference Example 2 In the same manner as in Reference Example 1, except that an octyl acrylate-vinyl pyridine copolymer was used in place of the octyl methacrylate-vinyl pyridine copolymer, the same procedure as in Example 12 was performed. A 60μ film was made.

The obtained membrane was subjected to the same permeation measurement as in Example 1. As a result, the permeation coefficient was 2.0 × 10 ⁻⁹ cm ³ (STP) · cm / cm ² · s.
It was ec · cmHg and α = 5.

Reference Example 3 In the same manner as in Reference Example 1, the operation before casting on a polytetrafluoroethylene plate was performed. The obtained solution is cast on a polybutylmethacrylate film (film thickness 50 to 60 μm) previously formed on a polytetrafluoroethylene plate. After that, in the same manner as in Reference Example 1, about 12.0% by weight
A 50-60 μm thick film containing cobalt-salen and a polybutylmethacrylate film were laminated to form a composite film. The obtained film was subjected to the same permeation measurement as in Example 3 with the cobalt-salen-containing film surface facing the secondary side (vacuum side). As a result, the permeation coefficient was 1.2 × 10 ⁻⁹ cm ³ (STP ) ・ C
m / cm ² · sec · cmHg and α = 6.

[Effects of the Invention] The oxygen-enriched film of the present invention has excellent handling strength and durability, and is particularly excellent in that an oxygen permeation selectivity α value of 10 or more can be achieved. Have.

Claims (6)

[Claims] 1. A polymer film for oxygen enrichment comprising a high-molecular polymer containing a metal complex of a porphyrin compound dispersed therein. 2. The oxygen-rich compound according to claim 1, wherein the metal complex of the porphyrin compound is a meso-tetra (α, α, α, α-o-pivalamidophenyl) porphinatocobalt (II) complex. Polymer film for chemical conversion. 3. A metal complex of a porphyrin compound having an imidazole compound as an axial ligand.
Item 3. A polymer film for oxygen enrichment according to any one of items 2 to 2. 4. The polymer film for oxygen enrichment according to any one of claims 1 to 3, wherein the high molecular polymer is an alkyl (meth) acrylate polymer. 5. The oxygen-enriching polymer film according to claim 1, wherein the metal complex of the porphyrin compound is contained in an amount of 1 to 50% by weight. 6. A composite film in which a high molecular polymer film containing a metal complex of a porphyrin compound dispersed therein and another high molecular polymer film are laminated to form a composite film. The polymer film for oxygen enrichment according to any one of item 5.