JP3084522B2 - Method for producing oxygen adsorbent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an oxygen adsorbing / desorbing agent. It relates to a manufacturing method.

[0002]

2. Description of the Related Art When oxygen in air is separated and sampled, a pressure-variable air separation method (PSA) is used in which oxygen or nitrogen is preferentially adsorbed and the pressure or temperature is changed to separate oxygen by changing the pressure or temperature. ) Or a temperature-varying air separation method (TSA) is known. As the adsorbent, a natural or synthetic zeolite that preferentially adsorbs nitrogen, carbon molecular sieves in which oxygen adsorbs faster than nitrogen, and improved ones thereof are used.

[0003]

However, in each of the above-mentioned devices, it is difficult to obtain high-purity oxygen because both of them adsorb oxygen and nitrogen, and to obtain high-purity oxygen, the yield is sacrificed. I had to.

[0004] Various complexes are known to have oxygen adsorbing ability. However, they usually have a problem that they do not react with oxygen unless the temperature is lower than room temperature, and they deteriorate in a solution state.

[0005] Therefore, the present invention provides an oxygen absorber which reacts reversibly only with oxygen at room temperature, does not deteriorate even when used repeatedly, and can provide high-purity oxygen in high yield and low power consumption. An object of the present invention is to provide a method for producing a desorbing agent.

[0006]

To achieve the above object SUMMARY OF THE INVENTION The manufacturing method of an oxygen adsorption-desorption agent of the present invention, ion exchange
In producing an oxygen adsorbing agent by dispersing and fixing a complex having an oxygen adsorption ability in an exchange resin, an axial ligand capable of coordinating the complex is introduced into the ion exchange resin by ionic bonding or Dispersively fixed by covalent bonds, then the axial ligand
In an inert gas atmosphere
Below, the complex was dissolved in a polar solvent at 70-130 ° C.
It is characterized in that the complex is coordinated with the axial ligand by dipping in a complex solution .

The above-mentioned ion exchange resin is used as a carrier for fixing a complex which selectively adsorbs and desorbs oxygen. The axial ligand is used to increase the oxygen adsorbing ability of the complex, but also plays a role as a chain for fixing the complex to the ion exchange resin. Various types of these can be used depending on the bonding structure between the ion exchange resin and the axial ligand. Note that, for example, in the case of a complex having a six-coordinate structure, an axial ligand refers to a ligand coordinated to the fifth or sixth coordination site. In English, an axial base is used. Or, it is said to be axial ligand.

[0008] First, pyridine,
Imidazole, alkylamine or a derivative thereof, which has an ionic bond or a functional group such as a vinyl group.

This functional group is necessary for dispersing and fixing the axial ligand in the ion exchange resin. Examples of the axial ligand having an ionic bond as a functional group include:

3-methyl-1,1'-dodecyldiimidazolium iodide;

Embedded image

1- (3-aminopropyl) imidazole hydrochloride;

Embedded image

Sodium 4-pyridineethanesulfonate;

Embedded image

4-picolylamine hydrochloride;

Embedded image And the like.

The axial ligand having an ionic bond is
When the lone electron pair of the nitrogen atom of the imidazole or pyridine group is donated to the central metal of the complex, the complex coordinates, but when the portion having an ionic bond is close to the nitrogen atom, the electron pair donating property of the nitrogen atom Is weakened. As a result, the oxygen adsorption capacity of the complex may also be weakened. Therefore, a structure having at least one alkyl carbon between the complex and the ion binding portion of imidazole or pyridine is preferable, and more preferably three alkyl carbons are used. that's all,
The most preferred structure has 10 or more alkyl carbon atoms.

Examples of the axial ligand having a vinyl group as a functional group include, for example,

4-vinylpyridine;

Embedded image

1-vinyl imidazole;

Embedded image And the like.

Examples of the axial ligand having a hydroxyl group as a functional group include, for example, 4- (imidazole-1-yl) phenol;

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3-pyridinepropanol;

Embedded image

8- (imidazol-1-yl) octanol;

Embedded image And the like.

Examples of the axial ligand having an amine as a functional group include, for example,

1- (3-aminopropyl) imidazo-
Le;

Embedded image

4-aminopyridine;

Embedded image And the like.

[0024] Then as for dispersing fixing the axial ligand having ionic bond as a functional group can be used various kinds of ion exchange resins.

For example, the aforementioned 1- (3-aminopropyl)
A cation exchange resin is used when an imidazole group or a pyridine group is present in the cation part, such as imidazole hydrochloride, and a pyridine group or an imidazole group is present in the anion part, as in the case of the sodium 4-pyridineethanesulfonic acid. Use an anion exchange resin.

When a cation exchange resin is used, it is preferable to use a cation exchange resin having a sodium-type functional group. At this time, if a cation exchange resin having a proton functional group is used, protons remaining in the resin after the reaction may react with the complex to deteriorate the complex. Therefore, when a proton-type cation exchange resin is used, it is desirable to previously perform ion exchange with a cation such as Na ⁺ to convert it to a cation type other than proton.

In the case of 4-vinylpyridine or the like in which the functional group of the axial ligand is a vinyl group, this is fixed by a covalent bond. For example, an ion-exchange resin in which an axis ligand is dispersed and fixed is obtained by reacting an axis ligand having a vinyl group with a monomer such as styrene to synthesize a copolymer. Can be. This synthesis can be easily carried out according to a conventional method, but in addition to a crosslinking agent such as divinylbenzene, a polymerization initiator such as azobisisobutyronitrile, a dispersion / suspension stabilizer such as polyvinyl alcohol, It is necessary to add a polymer precipitant such as amyl alcohol.

As an ion exchange resin for dispersing and fixing an axial ligand having a hydroxyl group or an amine as a functional group, a cation exchange resin having a sulfone group can be used. When this type of resin is treated with, for example, phosphorus pentachloride,
The sulfone group is converted to sulfonyl chloride according to the following formula.

[0029]

Embedded image (In the above formula, R represents a resin.)

Since this sulfonyl chloride easily reacts with a hydroxyl group or an amine, the axial ligand can be dispersed and fixed in the cation exchange resin by this reaction.
For example, in the case of 8- (imidazol-1-yl) octanol, it is fixed by the following reaction.

[0031]

Embedded image (In the above formula, R represents a resin.)

In the case of 1- (3-aminopropyl) imidazole, it is fixed by the following reaction.

[0033]

Embedded image (In the above formula, R represents a resin.)

[0034] Io with the other as an ion exchange resin, generally a functional group capable of reacting with functional groups contained in the axial ligand
Any type of exchange resin can be used.

[0035] Thus, pre-axial ligand to the axial ligand of the distributed fixed axial ligand containing ion exchange resin, a complex having an oxygen adsorption capacity by coordination bond, dispersed secured within tree butter Let it.

As the complex having an oxygen adsorption ability, those generally known as oxygen carriers and the like can be used, and form a coordination bond with the axial ligand of the ion exchange resin containing the axial ligand. In this way, a material that reversibly adsorbs and desorbs oxygen at normal temperature and near normal pressure is selected. Examples of such a complex having an oxygen adsorption ability include a general formula;

Embedded image (Wherein R1, R2 and R3 are each hydrogen or OC
R4 represents hydrogen or a methyl group or a phenyl group; R5, R6, R7, and R8 represent hydrogen or an alkyl group or a phenyl group such as CH3; . )
A complex represented by

Or a general formula;

Embedded image (Wherein, R ¹ and R ² each represent hydrogen, a methyl group, or a phenyl group).

Further, a general formula;

Embedded image (In the above formula, R ¹ represents hydrogen or a phenyl group, and R ² represents hydrogen or an alkyl group such as CH ₃ ).

Each of these complexes has a four-coordinate structure, and usually has a six-coordinate structure and is stable. Therefore, when the axial ligand is coordinated to the fifth coordination site of this complex, the oxygen adsorbing ability of the sixth coordination site is increased, and oxygen is adsorbed here.

As this complex, generally, any complex can be used as long as it has an oxygen adsorption ability when the axial ligand is coordinated to the fifth coordination site. However, it is preferable to use one having a solubility in a polar solvent described later of 0.1 M or more. In particular,

(N, N'-bis (4-methoxysalicylaldehyde) dimethylethylenediamine) cobalt;

Embedded image

Or (N, N'-bis (4-methoxysalicylaldehyde) tetramethylethylenediamine) cobalt;

Embedded image Etc. can be raised.

To coordinate the complex with the axial ligand, it is necessary to bring the axial ligand dispersed and fixed in the ion exchange resin close to the complex. In other words, the complex ion
It is necessary to make it movable in the exchange resin and make contact with the axial ligand in the resin.

The contact between the two is carried out by dissolving the complex in a polar solvent to prepare a complex solution, immersing the axial ligand-containing ion exchange resin in the complex solution, It can be performed by heating to a temperature of 150 ° C., preferably 70 to 130 ° C. to swell the ion exchange resin. Thereby, the complex can move in the resin, and the coordination bond between the axial ligand fixed inside the resin and the complex becomes possible.

As the above polar solvent, for example,

Γ-butyrolactone;

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Dimethyl sulfoxide;

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Dimethylformamide;

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1-methyl-2-pyrrolidinone (N-methylpyrrolidinone)

Embedded image

Sulfolane;

Embedded image However, in order to reduce evaporation loss of the polar solvent during heating, it is preferable to use one having a high boiling point.

In addition, since the complex solution is heated, a dimerization reaction of the complex occurs due to oxygen dissolved in the complex solution, and the oxygen adsorbing ability of the complex may be deactivated. Therefore, when the axial ligand-containing ion exchange resin is immersed in the complex solution and heated, the solution is made oxygen-free by bubbling an inert gas such as an argon gas .

At this time, if the heating temperature of the complex solution is lower than 70 ° C., the swelling of the ion-exchange resin is insufficient, and it is difficult to carry out the coordination bond between the axial ligand and the complex sufficiently. When the heating temperature exceeds 130 ° C., the decomposition of the complex occurs, the evaporation loss of the polar solvent increases, and the energy of the heating source is wasted.

As described above, the complex solution is heated and ion-exchanged.
By coordinating the axial ligand in the exchange resin with the complex, the oxygen adsorbing / desorbing agent of the present invention can be obtained, but in this state, the complex not coordinated to the axial ligand is It remains in the ion exchange resin due to physical adsorption. The complex that could not coordinate is not only weak in oxygen adsorption capacity, but also inhibits the movement and diffusion of oxygen in the oxygen adsorption / desorption agent during oxygen adsorption / separation, degrading the performance of the oxygen adsorption / desorption agent. There is a risk of lowering.

[0054] Therefore, after the above-mentioned coordination bond, Lee
It is preferable to remove the complex remaining in the on-exchange resin by physical adsorption. The removal of the complex can be carried out by separating the obtained oxygen adsorbing / desorbing agent from the complex solution and washing with an appropriate solvent such as acetone.

Then, by drying the washed oxygen adsorbing / desorbing agent by vacuum drying or the like, the polar solvent and the above-mentioned washing solvent contained in the obtained oxygen adsorbing / desorbing agent are removed, and the swollen resin is recovered. It is possible to obtain an oxygen adsorbing / desorbing agent which contracts to a state and in which a complex having oxygen adsorbing ability is dispersed and fixed in an ion exchange resin.

[0056] Incidentally, the axial ligand containing these functional groups, Io
The exchange resins and complexes are given as examples and do not limit the scope of the present invention, and various ones can be used depending on the conditions.

[0057]

When the above-mentioned complex alone is in a solution, it does not usually exhibit an oxygen adsorbing ability enough to separate oxygen around room temperature around 25 ° C. In addition, a degradation known as the dimerization reaction occurs.

However, in the oxygen adsorbing / desorbing agent of the present invention, since the complex is dispersed and fixed in the ion exchange resin, the thermal vibration of the complex is suppressed, and as a result, the complex is placed at a low temperature, Shows sufficient oxygen adsorption capacity so that oxygen can be separated at room temperature. Furthermore, since it is dispersed and fixed, a dimerization reaction is prevented, and deterioration of the complex is eliminated.

The oxygen adsorbing and desorbing agent can easily desorb and release oxygen by heating or reducing the pressure after adsorbing oxygen, and can repeatedly adsorb and desorb oxygen.

[0060]

The present invention will be described below in more detail with reference to Examples and Comparative Examples.

Example 1 1,2-diamino-2-methylpropane;

Embedded image A solution of 4.41 g (0.05 mol) dissolved in 20 ml of ethanol at a temperature of 90 ° C.

4-methoxysalicylaldehyde;

Embedded image 15.22 g (0.05 mol) was added and reacted,

Bis (4-methoxysalicylaldehyde)
Dimethylethylenediamine;

Embedded image Was obtained as a yellow solution.

To this, 12.45 g of cobalt acetate tetrahydrate was added.
(0.05 mol), and a dark-lit precipitate was obtained. This is left to cool, vacuum-dried after suction filtration, and a complex having oxygen adsorbing ability: (N, N'-bis (4-methoxysalicylaldehyde) dimethylethylenediamine) cobalt (hereinafter referred to as Co (4-MeOSal) Dmen). ) 23 g (about 85% yield).

The thus synthesized Co (4-MeOSa)
l) 0.3 g of Dmen was dissolved in 10 ml of γ-butyrolactone to obtain a 0.072M complex solution. Into this complex solution, 2 g (dry weight) of a porous copolymer granular resin having a diameter of about 1 mm obtained by copolymerizing 4-vinylpyridine and styrene by an ordinary method is immersed in an oxygen-free state, and heated to 90 ° C. The mixture was refluxed for 4 hours under an argon gas flow.

After cooling, the complex solution and the resin were separated, and the resin was washed with acetone to remove the physically adsorbed complex.
Finally, vacuum drying was performed at 80 ° C. for 15 hours to obtain 1.7 g of an oxygen adsorbing / desorbing agent in which Co (4-MeOSal) Dmen was dispersed and fixed in the porous copolymer granular resin.

The adsorbed amounts of oxygen and nitrogen gas in the obtained oxygen adsorbing / desorbing agent were measured by an electronic balance by a gravimetric method. As a result, the adsorption amount of nitrogen gas was so small as to be unmeasurable, but the adsorption capacity shown in the figure was obtained for oxygen gas. Incidentally, 4
-The porous copolymer granular resin composed of vinylpyridine and styrene does not have the ability to adsorb oxygen and nitrogen gas.

COMPARATIVE EXAMPLE The same operation as in Example 1 was carried out except that the complex solution was treated at room temperature without heating. As a result, the ability of the obtained resin to adsorb oxygen gas was extremely low.

Example 2 According to a conventional method, using tin (300 g) as a catalyst, 30 g of 2,3-dimethyl-2,3-dinitrobutane; (CH ₃ ) ₂ C (NO ₂ ) C (CH ₃ ) ₂ NO ₂ Treatment with 37% aqueous hydrochloric acid gave 10.9 g of tetramethylethylenediamine; (CH ₃ ) ₂ C (NH ₂ ) C (CH ₃ ) ₂ NH ₂ (55% yield).

This was reacted with 15.22 g of 4-methoxysalicylaldehyde and 12.45 g of cobalt acetate tetrahydrate in the same procedure as in Example 1 to obtain a complex (N, N ') having an oxygen adsorption ability. -Bis (4-methoxysalicylaldehyde) tetramethylethylenediamine) cobalt (hereinafter referred to as Co (4-MeOSal) Tmen) 1
7.6 g was obtained (80% yield).

The thus synthesized Co (4-MeOSa)
l) 0.88 g of Tmen was dissolved in 5.0 ml of 1-methyl-2-pyrrolidinone to obtain a 0.40 M complex solution.

Thereafter, 1 g of a granular resin of a porous copolymer of 4-vinylpyridine and styrene was obtained in the same procedure as in Example 1.
Co (4-MeOSal) Tmen was dispersed and fixed in (dry weight) to obtain 0.8 g of an oxygen adsorbing / desorbing agent.

The oxygen gas adsorption / desorption amount of the obtained oxygen adsorption / desorption agent was measured using an electronic balance. In this measurement, the temperature was -2.
The temperature was varied between 0 ° C. and + 50 ° C., and the oxygen adsorption / desorption amount based on the temperature change was measured.

As a result, when the oxygen partial pressure was 500 Torr, the amount of adsorbed and desorbed oxygen was 0.8 mg per 1 g of the granular resin. This temperature fluctuation type oxygen adsorption / desorption test was repeated 200 times, but the oxygen adsorption / desorption amount did not change.

Example 3 First, 1,1'-dodecamethylenediimidazole was prepared by a conventional method;

Embedded image

A solution of 22.7 g (7.50 × 10 ⁻³ mol) of 1,1′-dodecamethylenediimidazole in toluene (200 ml) was charged with 5.38 of iodomethane.
g (3.75 × 10 ⁻³ mol) of a toluene solution (50 ml) was added dropwise, and the mixture was reacted at 50 ° C. overnight. Then, a white tea solid was separated by filtration and washed with toluene. Then, it was vacuum-dried at 100 ° C. to obtain 15.0 g of 3-methyl-1,1′-dodecyldiimidazolium iodide as an axial ligand (yield 9).
0%).

On the other hand, a proton-type cation exchange resin, trade name Amberlyst [15] (Tokyo Organic Chemical Industry Co., Ltd.)
(10 g) was ion-exchanged with 100 equivalents (176 g) of sodium hydroxide under distilled water to obtain a sodium-type cation exchange resin. Next, 0.5 g of the sodium-type cation exchange resin was ion-exchanged with 2.5 equivalents (3.47 g) of the 3-methyl-1,1'-dodecyldiimidazolium iodide under distilled water. Na of the filtrate
From the measurement of the ion concentration, the ion exchange rate was 48%.

Then, the compound synthesized in Example 2 (Co
1.324 g of (4-MeOSal) Tmen was dissolved in 10 ml of 1-methyl-2-pyrrolidinone to prepare a 0.30 M complex solution. In this complex solution, 0.5 g of the ion exchange resin introduced with the above-mentioned axial ligand was immersed under argon gas and refluxed at 100 ° C. for 3 days.

Thereafter, in the same procedure as in Example 1, an oxygen adsorbing / desorbing agent having Co (4-MeOSal) Tmen embedded in an ion exchange resin was obtained.

As a result of measuring the amount of oxygen gas adsorbed on the obtained oxygen adsorbing / desorbing agent, 15.3 mg of oxygen was adsorbed per 1 g of resin at an oxygen partial pressure of 300 Torr and an adsorbing temperature of 25 ° C.

Example 4 After drying 20 g of the cation exchange resin used in Example 3, it was put into a mixed solvent of 125 g of phosphorus pentachloride / 250 g of phosphorus oxychloride, and reacted at 100 to 110 ° C. for 48 hours under nitrogen. It was converted to a sulfonyl chloride type cation exchange resin.

Next, 8- (imidazole-1) was obtained by a conventional method.
-Yl) octanol was synthesized, and 7 g of 8- (imidazol-1-yl) octanol obtained was combined with 1-methyl-2
-Dissolved in pyrrolidinone, added dropwise to 2.0 g of the above sulfonyl chloride type resin at 0 ° C under nitrogen, reacted at 80 ° C for 3 hours, and covalently bound 8- (imidazol-1-yl) octanol to the resin. Was dispersed and fixed.

The complex Co synthesized in Example 2 was used.
(4-MeOSal) Tmen was dissolved in 1-methyl-2-pyrrolidinone to prepare a 0.3 M solution of the complex. 2 g of the ion-exchange resin in which the above-mentioned axial ligand was dispersed and fixed was immersed in this solution, and refluxed at 100 ° C. for 24 hours in an argon gas atmosphere.

Thereafter, an oxygen adsorbing / desorbing agent having Co (4-MeOSal) Tmen embedded in an ion exchange resin was obtained in the same procedure as in Example 1.

As a result of measuring the amount of oxygen gas adsorbed on the obtained oxygen adsorbing / desorbing agent, when the oxygen partial pressure was 300 Torr and the adsorption temperature was 25 ° C., the amount of adsorbed oxygen was 7.62 mg per 1 g of the resin.

[0086]

As described above, according to the method for producing an oxygen adsorbing / desorbing agent of the present invention, an axial ligand to which a complex can be coordinated is formed.
Since the ligand is dispersed and fixed in the ion exchange resin, the axial ligand, which is a relatively small molecule, can move faster as a result of physical diffusion, rather than dissolution diffusion, in the pores. Thus, the reaction rate of the coupling between the axial ligand and the ion exchange resin is faster, since the complex having an oxygen adsorption capacity can be a large amount introduce axial ligand of coordination bond, an ion exchange resin A large amount of complex can be easily dispersed and fixed.

[0087] Further, when to be coordinately bound complexes with oxygen adsorption capacity in axial ligand of the ion exchange resin, complex complex solution 70 to 130 ° C., which was dissolved in a polar solvent, Jikuhaii
By immersing the ion-exchange resin in which the particles are dispersed and fixed , the ion-exchange resin can be swollen and the complex can be moved into the resin, so that the coordination bond between the complex and the axial ligand can be sufficiently improved. Can be done. And 70-
Inert the immersion work in the complex solution heated to 130 ° C.
Since it is performed in a gas atmosphere, the oxygen dissolved in the complex solution
The resulting complex dimerization reaction is suppressed, and the complex absorbs oxygen.
The ability to prevent inactivation can be prevented.

As a result, it is possible to obtain an oxygen adsorbing / desorbing agent which is not deteriorated by the dimerization reaction of the complex and can maintain excellent oxygen adsorbing ability for a long period of time. In addition, since this oxygen adsorbing and desorbing agent only adsorbs and desorbs oxygen, it is possible to obtain high-purity oxygen in a high yield by using it as an adsorbent for PSA or TSA,
Power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing the oxygen adsorbing ability of an oxygen adsorbing / desorbing agent produced in Example 1.

Claims (1)

(57) [Claims] 1. In producing an oxygen adsorbing / desorbing agent by dispersing and fixing a complex having an oxygen adsorbing ability in an ion exchange resin,
An axial ligand to which the complex can be coordinated is introduced into the ion-exchange resin to be dispersed and fixed by ionic or covalent bonding, and then the ion-exchange is performed by dispersing and fixing the axial ligand. Tree
The complex is dissolved in a polar solvent under an inert gas atmosphere.
The complex was immersed in a complex solution at 70 to 130 ° C.
And coordinating the axial ligand with the axial ligand .