JPH0324403B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a gas selective separation material useful for separating oxygen. Oxygen is one of the most widely and widely used gases, and its fields of use include welding and cutting steel materials, iron manufacturing such as blowing into blast furnaces, open hearths, and converters, various metal smelting applications, Used as a chemical raw material for manufacturing various petrochemical products, cement in the ceramic industry,
It is known for its uses, including the use of oxygen-enriched air, for manufacturing refractories, glass, etc., for activated sludge treatment of urban sewage and general industrial wastewater, and for medical purposes. The amount of oxygen used in Japan has reached 9 to 10 billion ^cubic meters, most of which is used for the iron and steel industry. [Prior Art] Industrial production of oxygen has been carried out since the beginning of this century by a cryogenic separation method. This method is considered to be the most suitable method when producing large amounts of oxygen using large-scale equipment, but it requires an extremely large amount of energy, and when used on-site, etc. It is necessary to once fill it into a pressure-resistant container and transport it, which results in a significant increase in cost. Also, as a method for producing oxygen on a relatively small to medium scale, a method has recently appeared that separates oxygen from air at high concentrations by utilizing the difference in the amount of nitrogen and oxygen adsorbed onto adsorbents such as zeolite, molecular sieves, and carbon. It is particularly used for various wastewater treatment, blowing into various furnaces, medical purposes, etc. However, the power consumption required to produce oxygen is high, and the cost of producing oxygen is high. In addition, as a special method, methods using metal complexes are being researched. It has been known for a long time that the cobalt salt of Schizuf's base combines with oxygen to form an oxygen complex, but the complex itself decomposes during repeated adsorption and desorption of oxygen, making it difficult to use as an economical system. Ta. Research to improve durability has continued, including research by the US Air Force in the late 1960s, and relatively durable products such as fluorine-substituted material called fluorine have been discovered. However, the method using this oxygen complex has the drawback that the absorption of oxygen must be carried out at around room temperature, such as 27-38°C, and the release must be carried out at a high temperature, e.g. 82°C, which requires raising and lowering the temperature for the operation. Ta. JP-A-59-12707 discloses a method for selectively permeating and separating oxygen from the air using a membrane in which a solution containing an oxygen complex is held on a porous membrane support. In this method, oxygen can be continuously separated using the pressure difference on both sides of the membrane while keeping the temperature constant. In such a membrane method, it is necessary that the ratio of oxygen and nitrogen permeation rates is large, and the oxygen permeation rate is high.
For this purpose, important factors include the rate of reaction between oxygen and the complex and the diffusion coefficient of the resulting oxygen complex. However, Chemical Reviews, Vol. 79, p. 139, cited in the above-mentioned JP-A-59-12707,
(1979), Canadian Journal of Chemistry, Vol. 54, p. 3424 (1976), Canadian Journal of Chemistry, Vol.
The American Chemical Society Volume 102
3285 (1980), etc., although many oxygen complexes have been discovered and studied, bulky ligands are still required to stably and reversibly adsorb and desorb oxygen. was required, and the molecules of oxygen complexes had to inevitably become large molecules. With this, a large diffusion coefficient cannot be expected. On the other hand, various cobalt complexes having relatively small molecular weight ligands have been studied, but to date no substance that reversibly adsorbs and desorbs oxygen has been found. [Purpose of the Invention] We conducted extensive research with the aim of searching for complexes with relatively small ligands that adsorb and desorb oxygen quickly and reversibly. The present invention was achieved by discovering the groundbreaking fact that a complex obtained by reacting with a salt has the ability to reversibly adsorb and desorb oxygen despite its relatively low molecular weight. That is, the present invention uses (A) a Co salt and (B) dipropylene triamine having the formula _H2N - _CH2 - _CH2 - _CH2 -NH- _CH2 - _CH2 - _{CH2- NH2} or a derivative thereof. The present invention relates to an oxygen selective separation material made of a reaction product obtained by contact. In order to obtain the above oxygen selective separation material, (A) and (B) may be brought into contact in the presence of an axial base, or
This invention relates to an oxygen selective separation material obtained by adding an axial base to the reaction product of (A) and (B). Similarly, in obtaining the above oxygen selective separation material (A)
The present invention relates to an oxygen selective separation material obtained by contacting (B) and (B) primarily in the presence of a non-aqueous solvent, or by adding the solvent to the reaction product of (A) and (B). The present invention also relates to an oxygen selective permeable membrane containing these oxygen selective separation materials and an oxygen selective absorption liquid containing these oxygen selective separation materials. [Structure of the Invention] Next, the content of the present invention will be explained in detail. The cobalt salt of (A) is dipropylenetriamine _H2N - _CH2 - _CH2 - _CH2 -NH- _CH2 of the present invention.
-CH ₂ -CH ₂ -NH ₂ or its derivatives, or anything that forms a complex with various axial bases to be added may be used, but the following
An example is a Co compound. That is, cobalt oxide, cobalt hydroxide, halides such as cobalt fluoride, cobalt chloride, cobalt bromide, and cobalt iodide, and their hydrates, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt cyanide, and cobalt thiocyanate. , inorganic acids and organic acid salts such as cobalt perchlorate, cobalt periodate, cobalt tetrafluoroborate, cobalt oxalate, cobalt tartrate, and their hydrates,
Further examples include double salts such as cobalt alum and organic cobalt compounds such as cobaltocene, but the valence of cobalt can be arbitrarily selected. Among the above cobalt salts, divalent cobalt salts, particularly inorganic salts, are preferred, such as Co(SCN) ₂ , CoF ₂ ,
_CoCl2 , _CoBr2 , _CoI2 , Co( _ClO4 ) ₂ , Co( _BF4 ) ₂ ,
Co(OCOCH ₃ ) ₂ is exemplified as the most preferred cobalt salt. (B) required to react with Co salt and form Co complex
Dipropylenetriamine is an amine compound of
H ₂ N−CH ₂ −CH ₂ −CH ₂ −NH−CH ₂ −CH ₂ −
Examples include CH ₂ -NH ₂ and derivatives thereof. (Hereinafter, simply referred to as "amine compound") The derivative referred to here means that all or part of H in the formula H ₂ N-CH ₂ -CH ₂ -CH ₂ -NH-CH ₂ -CH ₂ -CH ₂ -NH _{2 is} Compounds obtained by chemically bonding other atoms or functional groups substituted with other atoms or oligomers, polymers, etc., compounds with unsaturated bonds obtained by partially eliminating hydrogen, and other than the above H means a compound having both a substituent and an unsaturated bond. Although there are no particular limitations on the way the derivatives are bonded, _H2N - _CH2 - _CH2 - _CH2 -NH- _CH2 - _CH2 - _CH2 -NH-A B-HN- _CH2 - _CH2 - _CH2 -NH- _CH2 - _CH2 - _CH2 -NH-A (However, A and B represent a functional group etc. which substituted H.) Such derivatives are exemplified. It also includes a cyclic body in which two substituted functional groups, oligomers, polymers, etc. are bonded to each other at other ends. In substitution or dehydrogenation, the number of substituents and the number of unsaturated bonds are not limited. Examples of functional groups, oligomers, and polymers substituting H in the above general formula include the following. Functional groups include halogen atoms such as F, Cl, Br, and I, carboxyl groups, or metal salts thereof (-
COOH, -COOM), sulfonyl group ( _-SO3H ),
Sulfinyl group (-SO ₂ H), acid anhydride (-CO-
O-CO-), oxycarbonyl group (-COOR),
Hawaformyl group (-COX), carbamoyl group (-
CONH ₂ ), hydrazinocarbonyl group (-
CONHNH ₂ ), imide group (-CO-NH-CO-),
Amidino group (

[Formula]), nitrile group (-CN), isocyano group (-NC), formyl group (-
CHO), carbonyl group (C=O), hydroxyl group (-
OH), alkoxy group (-OR), phenoxy group (

〔Example〕

The content of the present invention will be explained below with reference to Examples. In the Examples of the present application, the gas permeation rate was measured as follows. That is, a flat membrane made of polytrimethylvinylsilane was installed as a base membrane in a cylindrical glass cell with an outer diameter of 45 mm, and a solution or slurry containing the selective separation material to be tested was injected onto the top of the membrane.
The permeation test gas was passed through with stirring. On the other hand, the permeation rate Q was determined by reducing the pressure below the base membrane (secondary side) and analyzing the amount of gas permeated within a certain period of time using gas chromatography. Note that Q in this example is a value measured at 30° C. unless otherwise specified, and its unit is cc/cm ² ·sec·cmHg. Further, α represents the velocity ratio of oxygen to nitrogen (Q _O2 /Q _N2 ). The amount of gas absorbed was measured as follows. That is, a predetermined amount of the selective separation material or its solution was poured into a glass container with a known volume, and then the inside of the container was depressurized and degassed. After sufficient degassing, the gas to be measured was introduced while the container was maintained at 23°C, and the amount absorbed was measured using a gas burette. Measurement of gas absorption amount in solution state is as follows:
The absorption amount of the solvent used alone was measured as a blank, and this was subtracted to determine the absorption amount of the separating agent. Example 1 (a) Preparation of separation material 2.3 ml of dipropylene triamine in a 50 ml flask
ml and 0.95 g of cobalt thiocyanate were charged, and when stirred under nitrogen, a slight heat was generated and the reaction occurred. After 15 minutes, 9 ml of dimethyl sulfoxide (hereinafter simply referred to as DMSO) was added, and the mixture was heated to 60°C and reacted for 2 hours to obtain a deep red homogeneous solution. (b) Measurement of gas permeation rate Place the separation agent prepared in (a) in the gas permeation measurement cell.
10 ml was taken out and air was circulated at a rate of 0.5/min. Next, the secondary pressure was adjusted to 2 mmHg and the measurement temperature was adjusted to 30°C, and the permeated gas was analyzed by gas chromatography, and the oxygen concentration was 62.3.
It was found that %. Further, the oxygen permeation rate Q _O2 at this time was 4.0×10 ^-6 and α was 5.2. Example 2 (a) Preparation of separation agent 2.3 ml of dipropylene triamine and cobalt thiocyanate were prepared in exactly the same manner as in Example 1 (a).
After reacting 0.95 g, 2.2 ml of 1-methylimidazole was added and the reaction was continued for 10 minutes. After 7 ml of DMSO was added and the mixture was stirred at 60°C for 2 hours, a dark red homogeneous solution was obtained. (b) Measurement of gas permeation rate When an air gas permeation test was conducted in the same manner as in (b) of Example 1, the oxygen concentration of the permeated gas was 69.4.
It was %. Moreover, Q _O2 at this time was 3.7×10 ⁻⁶ and α was 8.6. It can be seen that α increases when 1-methylimidazole is used as the axial base. (c) Measurement of gas absorption amount Separating agent 5 prepared in (a) in a 25 ml glass container
After sufficient degassing, the amount of oxygen absorbed was measured using a gas bottle. The actual amount of oxygen absorbed is
It was determined by subtracting the amount of oxygen absorbed from the mixed solution of DMSO and 1-methylimidazole.
As a result, the amount of oxygen absorbed was 41.2 ml, which corresponded to 0.74 oxygen molecules per cobalt atom. The separation agent was degassed under reduced pressure and the amount of oxygen absorbed was measured again and found to be 8 ml. This indicates that the separating agent reabsorbs oxygen. Example 3 Example 2 A separating agent was prepared in exactly the same manner as in Example 2(a) except that 1.4 g of cobalt acetate was used instead of cobalt thiocyanate, and a dark reddish-brown homogeneous solution was obtained. Example 1(b) using this solution
When gas permeation performance was measured in the same manner as above, the oxygen concentration of the permeated gas was 38.5%, Q _O2 was 1.4 × 10 ^-6 , and α was 2.6. Example 4 A separating agent was prepared in exactly the same manner as in Example 2(a) except that 1.2 g of cobalt bromide was used instead of cobalt thiocyanate, and the gas permeation performance was tested in the same manner as in Example 1(b). As a result of measurement, the oxygen concentration of the permeated gas was 39%, Q _O2 was 3.3×10 ^-6 and α was 2.6. Example 5 (a) Preparation of separation material 1.31 g of cobalt thiocyanate in a 50 ml flask
After preparing (7.5 mmol) and replacing with nitrogen
7.5 ml of DMSO was added and stirred at room temperature for 30 minutes to obtain a blue homogeneous solution. After further adding 2.38 ml of DMSO, 2.68 g (20.0 mmol) of dipropylene triamine is added.
It turned red. Add to this 3.08g of N-methylimidazole
(37.5 mmol) was added and stirred at room temperature for 1 hour. The concentration of cobalt in the solution was 0.5 mmol/ml. Next, styrene copolymer resin particles (Diaion WA21, manufactured by Mitsubishi Kasei) were placed in a 50 ml flask.
4 g was taken, and the inside of the flask was depressurized and replaced with nitrogen. To this were added 4 ml of the above solution and 4 ml of DMSO under a nitrogen atmosphere. Volatile components are reduced to 70% after being left overnight.
C. and the cobalt complex was supported on the resin particles. (b) Measurement of oxygen absorption rate The flask containing the entire amount of the cobalt complex-supporting resin prepared in (a) was connected to a gas bottle containing oxygen via a bottle, and after reducing the pressure inside the flask, the bottle was opened and oxygen was introduced from the gas bottle. I fed it. By measuring the amount of oxygen reduction over time in the gas bottle and subtracting the space volume in the flask, which was measured in advance using nitrogen gas,
The oxygen absorption rate of the cobalt-supported resin was measured. The results showed that the amount of oxygen absorbed, expressed as the molar ratio of oxygen molecules to cobalt atoms, after 5 minutes was
0.11, 0.16 after 10 minutes, 0.22 after 20 minutes, 1 hour after
It was 0.34. On the other hand, the absorption rate of nitrogen gas was measured in the same manner, but apart from the initial decrease in nitrogen in the gas burette by the space volume of the flask, there was no change over time. [Effects of the Invention] By using the oxygen selective separation material of the present invention, oxygen can be concentrated to a high concentration, and since the rate of adsorption and desorption of oxygen is fast, oxygen can be efficiently concentrated. Oxygen is widely used in all industries and is therefore useful in a wide range of industrial fields.

Claims (1)

[Claims] 1 (A) Co salt and (B) dipropylene triamine represented by the formula H ₂ N-CH ₂ -CH ₂ -CH ₂ -NH-CH ₂ -CH ₂ -CH ₂ -NH ₂ Oxygen selective separation material consisting of a reaction product obtained by contacting or a derivative thereof. 2. In the separation material described in claim 1, (A) and (B) are brought into contact in the presence of an axial base, or an axial base is added to the reaction product of (A) and (B). Oxygen selective separation material obtained by adding. 3. In the separation material according to claim 1 or 2, (A) and (B) are brought into contact mainly in the presence of a non-aqueous solvent, or (A) and (B) An oxygen selective separation material obtained by adding the solvent to a reaction product with.