JPS6257380B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a carbon monoxide (hereinafter CO) absorbing and separating agent, and particularly to a method for producing the above-mentioned solid separating agent that selectively absorbs CO and is less susceptible to water deterioration. Conventionally, gas separation agents of the formula _MMXo , aromatic (M: metal of Group 1-B such as Cu, M:
Aromatic hydrocarbon or halogenated dimetal salt complex of Group A metal such as Al, X: halogen, aromatic: C _6-12 monocyclic aromatic hydrocarbon or halogenated aromatic hydrocarbon Liquid absorbent consisting of aromatic hydrocarbon solution (Japanese Unexamined Patent Publication No. 57-21328),
Dimetallic salts containing CuAlX ₄ (X: halogen atom) (Japanese Patent Publication No. 48-35041) have been proposed, but these are all for absorbing and separating unsaturated hydrocarbon gases such as propylene. Moreover, the effective gas absorption component itself is unstable, and the absorption performance deteriorates in a short period of time, especially when moisture is present in the gas to be treated. Recently, liquid absorbents made of copper halide (), aluminum halide (), aromatic hydrocarbons (JP-A-58-24321), copper halide (), aluminum halide (),
Solid absorbent made of polystyrene (JP-A-Sho
58-49436), solid absorbent consisting of copper halide (), aluminum halide (), activated carbon or graphite (JP-A-58-124516)
A method was proposed to selectively absorb and separate CO, which is useful as a basic raw material for synthetic chemistry, from CO-containing mixed gases produced as by-products in steel mills, oil refineries, petrochemical plants, etc. However, the liquid absorbent described above, like the unsaturated hydrocarbon absorbent described above, has a remarkable deterioration property due to moisture, and cannot stably absorb and separate CO over a long period of time. The above-mentioned solid absorbent also has the problem of low water deterioration resistance and the amount of copper halide () and aluminum halide () that can be supported is small. Although activated carbon is less susceptible to water deterioration, it has the disadvantage that it adsorbs large amounts of not only CO but also other components in the mixed gas, and lacks selectivity for CO. The present invention eliminates these drawbacks and proposes a method for producing a solid CO absorption/separation agent that has highly selective absorption and separation performance for CO and has extremely low degradability with respect to water. That is, the present invention provides a method for producing a carbon monoxide absorbing and separating agent, which is characterized in that an organic solvent solution of copper halide (2) and aluminum halide (2) is brought into sufficient contact with porous alumina, and then free organic solvent is removed. It is about the method. Any of chlorine, bromine, iodine, and fluorine are effective as the halogen in the copper halide () in the present invention, but copper chloride or the like is usually used due to cost and availability. Any of chlorine, bromine, iodine, and fluorine are effective as the halogen of aluminum halide (), but aluminum chloride is usually used for the same reason as above. Note that since aluminum halide (2) generally contains impurities, it is purified by a sublimation method or the like before use, but it does not need to be purified to a high degree as in the conventional solution method described above. In addition, as the organic solvent in the method of the present invention,
Aromatic compounds such as benzene, toluene, and xylene, and general-purpose compounds such as carbon disulfide and dichloromethane are used. However, solvents that do not have the ability to dissolve the copper halide (2) and aluminum halide (2), or solvents that decompose, convert to ring atoms, or oxidize these compounds are not preferred. For example, carbon tetrachloride and chloroform have significantly lower solubility of aluminum halide () than the above-mentioned aromatic compounds, and are therefore unsuitable for use in the method of the present invention. Additionally, if the solvent contains water, the aluminum halide () will be partially decomposed and generate solids and halogen acids, so contamination of water into the solvent used should be strictly avoided. . Furthermore, the absorption separation agent obtained by the method of the present invention is
Since the desorption operation after CO absorption is usually performed under heating or reduced pressure, low boiling point solvents or highly volatile solvents are not preferred. This is because the absorption/separation agent produced by the method of the present invention is a product in which a complex salt as described below and alumina as a carrier are integrated, and the aluminum halide side of the complex becomes hydrophobic due to the cooperative action of alumina as a carrier and an organic solvent. This is because if this organic solvent were to volatilize during the desorption operation, the hydrophobicity would be lost and the deterioration property with respect to water would increase. Therefore, in the method of the present invention, aromatic compounds such as benzene, toluene, and xylene are preferred as organic solvents. In the method of the present invention, the above-mentioned copper halide (2) and aluminum halide (2) are dissolved separately or together in an organic solvent and brought into sufficient contact with porous alumina. Impregnation methods, dipping methods, spraying methods, etc. are used as the contact method, and among them, the most common method is the impregnation method, which does not use more organic solvent than necessary and uses a solution amount that is approximately equal to the pore volume of the alumina carrier. It is. By the way, the ability of the method of the present invention as an absorption/separation agent shows remarkable CO selectivity and absorbability when copper acts in a monovalent state. Aluminum halide () has the function of retaining this copper in a monovalent state, and in particular, both exist in equimolar amounts [for example, as CuAlX ₄ (X: halogen, the same applies hereinafter)] in the complex salts described below. It is thought that the ability is at its maximum when the Therefore, in the method of the present invention, in order to form such a complex salt, after bringing the above-mentioned organic solvent solution into sufficient contact with porous alumina, it is heated for 40 to 60 minutes in the absence of moisture, preferably in an inert gas. °C, 4~
Perform a heating operation for 2 hours. With this heating operation,
A complex salt consisting of Cu(), Al(), the organic compound, and X is formed, and it is presumed that the complex salt also forms some kind of bond with the alumina of the carrier as described above. By this heating operation, a portion of the free organic solvent is also removed. Note that the above heating operation may be performed before the organic solvent solution is brought into contact with porous alumina. As mentioned above, the ratio of copper halide () to aluminum halide () is preferably 1:1 in terms of molar ratio, and the excess aluminum halide ()
It is desirable to ensure that there is no such thing. The concentration of the organic solvent solution may be such that copper halide (2) and aluminum halide (2) can be dissolved, and there is no need to dilute it more than necessary.
In general, copper halide () and aluminum halide () have a total of 5% relative to alumina.
The solution concentration and amount may be as long as it supports ~50 wt%. Additionally, porous alumina is copper halide ()
A material having the ability to sufficiently disperse and immobilize aluminum halide () together with a part of the organic solvent is used. However, it must be something that does not reduce or oxidize Cu () and also does not decompose aluminum halide (). Such porous alumina preferably does not contain free water and has a sufficient surface area. If the surface area is too large, copper or aluminum may be fixed and inactivated more than necessary, or the pores may become too small, reducing the dispersibility of the complex salt. Therefore, it is fired at 110 to 1200°C, preferably 450 to 1100°C, more preferably 500 to 900°C, and becomes γ-, δ-, Θ-, etc. alumina, and BET
Surface area: 40-400m ² /g, preferably 50-300m ² /g
g is used. In the method of the present invention, after the above-mentioned contacting and heating operations, the free organic solvent is removed under reduced pressure. At this time, the same heating as described above (that is, heating at 40 to 60° C. in a moisture-free state, preferably in an inert gas) can also be applied. It is important to carry out this removal operation until the organic solvent in the liquid phase is exhausted. This is because the solid absorption and separation agent produced by the method of the present invention exhibits sufficient water resistance only when Cu () and Al () are completely immobilized on the porous alumina carrier, and the free organic solvent is removed from the liquid. This is because if it remains in the pores in a phase state, the selective absorption performance of CO will be easily deteriorated by water, as seen in the conventional liquid absorbent mentioned above. Hereinafter, the method of the present invention will be explained in more detail with reference to Examples. Example 1 Aluminum chloride () was used by purifying a commercially available special grade reagent (here, produced by Kishida Chemical Industry Co., Ltd.) by a sublimation method to remove impurities, and toluene was used as a commercially available special grade reagent (here, produced by Wako Pure Chemical Industries, Ltd.). (manufactured by Kogyo Co., Ltd.) was dehydrated with metallic sodium, distilled, and used. As copper chloride (), a commercially available special grade reagent (here, manufactured by Kojima Chemical Co., Ltd.) was used as is. 0.8 g of the above aluminum chloride () in a 200 ml rotary evaporator under dry nitrogen
(6 mmol) and the above copper chloride () 0.6 g (6 m
mol), added 20 ml of toluene to dissolve, and heated and kept at 60°C for 2 hours while stirring on a rotary evaporator. Note that the above nitrogen is commercially available nitrogen (here, high-purity nitrogen manufactured by Teikoku Sanso Co., Ltd.).
99.999%) was purified immediately before use by passing it through a column filled with commercially available Molecular Sieve 3A (here manufactured by Nikka Seiko Co., Ltd.). On the other hand, in another 200 ml rotary evaporator, a commercially available alumina A carrier (manufactured by Catalyst Kasei Co., Ltd. with an average pore diameter of 108
After pouring 10g of BET surface area 230m ² /g into the flask and thoroughly degassing the inside of the eggplant flask using a vacuum pump, add the previously prepared aluminum chloride () and copper chloride ( ) was added to the toluene solution. After stirring for 10 minutes, reduce the pressure inside the rotary evaporator (6mm
Hg) and left overnight to sufficiently remove toluene to prepare an absorbent. The amount of absorbent thus obtained was 11.93 g. To check the performance of this absorbent, it was placed in a 200ml rotary evaporator.
Combined with a container containing 1 atm carbon monoxide and nitrogen mixed gas (carbon monoxide partial pressure 0.79 atm, nitrogen partial pressure 0.21 atm) 1, absorption of carbon monoxide at 26°C while rotating a rotary evaporator. I performed the operation. This absorption operation was carried out by circulating a mixed gas of carbon monoxide and nitrogen at a rate of 1.4/min over the absorbent using an air pump. The mixed gas of carbon monoxide and nitrogen is a commercially available product (purity CO: 78.82 manufactured by Steel Chemical Industry Co., Ltd.).
%N ₂ :21.18%) was purified by passing it through a commercially available deoxygenation tower (manufactured by Nikka Seiko Co., Ltd.) immediately before use. The amount of carbon monoxide absorbed was measured at 26°C using the gas biuret method. Carbon monoxide absorption is rapid;
The amount of carbon monoxide absorbed after 10 minutes was 1.5 mmol. The absorbent was then heated to 90° C. at 1 atm to release the absorbed carbon monoxide. On the other hand, a container containing nitrogen gas (purified from the commercially available product mentioned above) 1 is combined with an air washing bottle containing distilled water, and an air pump is used to pass nitrogen gas through the air washing bottle to maintain a temperature of 26°C. Water (20,000 ppm) corresponding to the saturated water vapor pressure is mixed into nitrogen gas, and the gas is poured onto the absorbent after carbon monoxide is released at 0.8%.
min for 10 minutes (hereinafter, this operation is referred to as water treatment). After that, this absorbent was heated to 26°C with a mixed gas of 1 atm carbon monoxide and nitrogen (carbon monoxide partial pressure 0.79 atm, nitrogen partial pressure
0.21 atm) (purified from the commercially available product mentioned above) 1
The absorbent was connected to a container containing carbon monoxide, and an air pump was used to circulate the absorbent over the absorbent to perform the carbon monoxide absorption operation again. The absorption of carbon monoxide in this case is also rapid, with 10
After minutes, 2.4 mmol of carbon monoxide was absorbed. The absorbent was then heated to 90° C. at 1 atm to release the absorbed carbon monoxide. After that, the above water treatment, absorption and release are repeated,
The amount of carbon monoxide absorbed was measured. The results are shown in Table 3 below. Examples 2 to 4 The same operations as in Example 1 were carried out, except that the carrier shown in Table 1 was used instead of the alumina A carrier fired at 550°C in Example 1. The amount of carbon monoxide absorbed is also shown in Table 3 below.

[Table] Examples 5 to 7 The same operations as in Example 1 were performed except that the solvents shown in Table 2 were used instead of toluene in Example 1.
The results are also shown in Table-3.

【table】

[Table] Comparative Example 1 In a 200ml two-necked eggplant flask under dry nitrogen
0.8 g (6 mmol) aluminum chloride (), 0.6
g (6 mmol) of copper chloride () and toluene.
A liquid absorbent was prepared by adding 20 ml and dissolving the mixture, and heating and keeping it at 60°C for 2 hours while stirring using a magnetic stirrer. Put the above liquid absorbent into a 200 ml two-necked eggplant flask, and add 1 atm, a mixed gas of carbon monoxide and nitrogen (carbon monoxide partial pressure 0.79 atm, nitrogen partial pressure
0.21 atm) (used the same purified commercially available product as in Example 1, the same applies hereinafter) 1, and was stirred using a magnetic stirrer to absorb carbon monoxide at 26°C. The mixed gas of carbon monoxide and nitrogen was circulated over the absorbent at 1.4/min using an air pump. The amount of carbon monoxide absorbed is determined by the gas biuret method.
Measured at 26°C. Carbon monoxide absorption is rapid and 10
The amount of carbon monoxide absorbed after minutes was 2.8 mmol. The absorbent was then heated to 90°C at 1 atm to release the absorbed carbon monoxide. On the other hand, combine a container containing nitrogen gas (purity 99.999%) (used the same purified commercial product as in Example 1) with an air washing bottle containing distilled water, and use an air pump to wash the nitrogen gas. 26 by passing through the bottle
Water (20,000 ppm) at saturated steam pressure at 0.degree. C. was mixed into the nitrogen gas and the gas was circulated at 0.8 min. Then, while rotating the evaporator at 26°C, this absorbent was heated to a mixed gas of 1 atm carbon monoxide and nitrogen (carbon monoxide partial pressure 0.79 atm nitrogen partial pressure).
0.21 atm) 1 and circulated over the absorbent using an air pump to absorb carbon monoxide again. The amount of carbon monoxide absorbed at this time was 0 mmol. [Comparative test for selective absorption capacity] The manufacturing conditions of Example 1 were followed using the absorbent manufactured in Example 1 and activated carbon (Shirasagi C surface area, manufactured by Takeda Pharmaceutical Co., Ltd., surface area approximately 1300 m ² /g) in place of the alumina A carrier. In order to compare the _selective absorption ability of carbon monoxide with respect to _the absorbent manufactured by A comparative test was conducted using a pressure of 0.19 atm). Example 1: 10g of each absorbent was collected.
When the gas absorption amount was measured under the test conditions of
The absorbent of Example 1 absorbed 2.3 mmol of carbon monoxide and 0.04 mmol of carbon dioxide, but the absorbent using activated carbon absorbed 2.2 mmol of carbon monoxide and 0.04 mmol of carbon dioxide.
Absorbed 0.24 mmol. A performance test similar to the above was conducted using activated carbon having a smaller surface area than the above activated carbon, but the gas absorption amount was almost the same as above. From the above tests, the absorbent of Example 1 using activated carbon instead of the alumina A carrier absorbs carbon monoxide and a considerable amount of carbon dioxide, whereas the absorbent of Example 1 absorbs carbon monoxide and a considerable amount of carbon dioxide. It can be seen that the absorption amount of carbon dioxide is low and the selective absorption ability of carbon monoxide is very excellent. As is clear from the above Examples, Comparative Examples, and Comparative Tests, the carbon monoxide absorption and separation agent produced by the method of the present invention has excellent selective absorption ability for carbon monoxide, and has an extremely low degree of deterioration with respect to water. It can be stably used for absorption and separation of carbon monoxide for a long period of time.

Claims (1)

[Claims] 1. A carbon monoxide absorbing and separating agent characterized in that an organic solvent solution of copper halide () and aluminum halide () is brought into sufficient contact with porous alumina, and then free organic solvent is removed. manufacturing method. 2 Fired at 500-900℃, surface area 50-300
2. Process according to claim 1, characterized in that porous alumina of m ² /g is used. 3. The method according to claim 1 or 2, characterized in that an aromatic compound is used as the organic solvent.