JPS6211897B2 - - 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 have been used with the formula MMX _o , 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 involves sufficiently contacting a porous inorganic oxide with an organic solvent solution of copper halide (2), aluminum halide (2), and an organic compound having two or more aromatic rings, and then removing the free organic solvent. The present invention relates to a method for producing a carbon monoxide absorption and separation agent characterized by the following. As the halogen for the copper halide (2) in the method of the present invention, any of chlorine, bromine, iodine, and fluorine are effective, but cuprous chloride is usually used because of its 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. Further, examples of the organic compound having two or more aromatic rings in the method of the present invention include those having a relatively low molecular weight such as diphenylmethane, and aromatic polymers such as linear polystyrene having a molecular weight of several tens of thousands.
However, due to problems with the preparation method, linear polystyrene or its derivatives which are soluble in organic solvents are preferred.
The molecular weight of such linear polystyrene is 200 or more, preferably 500 to 50,000, more preferably 800.
~10000 things. Further, the above-mentioned polystyrene derivatives or modified products may be used as long as they are soluble in the organic solvent used in the method of the present invention. Furthermore, 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), aluminum halide (2), and organic compounds having two or more aromatic rings, or solvents that decompose, reduce, 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 solid content and halogen acid, so contamination of water into the solvent used should be strictly avoided. be. In addition, the absorption/separation agent obtained by the method of the present invention is a product in which a complex salt and an inorganic oxide as a carrier are integrated as described below, and the aluminum halide side of the complex salt is an inorganic oxide as a carrier and an aromatic ring. It is presumed that hydrophobicity is maintained due to the cooperative action of an organic compound having two or more of these and an organic solvent. ( ), it is preferable to use an organic solvent that has the ability to sufficiently dissolve not only organic compounds having two or more aromatic rings but also compounds (complex salts) formed from these by the heating operation described below. 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 copper halide (2) and aluminum halide (2) are dissolved separately or together in an organic solvent, and an organic compound having two or more aromatic rings is added and dissolved therein. This is brought into sufficient contact with the porous inorganic oxide.
The contact method used is impregnation, dipping, spraying, etc. Among them, the impregnation method does not use more organic solvent than necessary and requires a sufficient amount of solution to correspond to the pore volume of the inorganic oxide. Common. By the way, the ability of the method of the present invention as an absorption/separation agent shows remarkable CO selectivity and absorption when copper is acting 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 the porous inorganic oxide, it is heated for 40 min in the absence of moisture, preferably in an inert gas. ~60℃, 4
Perform a warming operation for ~2 hours. Through this heating operation, a complex salt consisting of Cu(), Al(), an organic compound originating from the organic solvent, and It is presumed that some type of bond is also formed with organic compounds having two or more. 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 the porous inorganic oxide. 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 is copper halide (),
Aluminum halide () and aromatic ring 2
It is sufficient that the concentration is such that an organic compound having two or more aromatic rings can be dissolved therein. In particular, it is necessary that an organic compound having two or more aromatic rings be sufficiently and uniformly dissolved. Generally, the total amount of copper halide (), aluminum halide (), and organic compounds having two or more aromatic rings is 5 to 50% relative to the inorganic oxide.
The solution concentration and amount may be such that 50 wt% is supported. In addition, the organic compound having two or more aromatic rings has a weight ratio of 0.2 to 5, especially 0.4 to 2, relative to copper halide () and aluminum halide ().
A range of is preferred. Further, the porous inorganic oxide used has the ability to sufficiently disperse copper halide (2), aluminum halide (2), and an organic compound having two or more aromatic rings. However, Cu
It needs to be something that does not reduce or oxidize () and also does not decompose aluminum halide (). Such porous inorganic oxides preferably do not contain free water and have 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, 110-1200℃, preferably 450-1100℃,
More preferably, those baked at 500 to 900°C and have a BET surface area of 40 to 400 m ² /g, preferably 50 to 350 m ² /g are used. Specific examples include alumina, silica, silica alumina, titania, silica magnesia, zirconia, alumina magnesia, and the like. Among them, those that show excellent dispersion support are:
They are alumina, silica, and silica alumina. In particular, because of their adjustable pore structure, they uniformly disperse and immobilize organic compounds having two or more aromatic rings. Alumina has the best ability to do this. 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 because Cu() and Al() are completely immobilized on the porous inorganic oxide carrier and have two or more aromatic rings. When the organic compound is dispersed and immobilized, and the free organic solvent remains in the pores in a liquid phase, it is easily absorbed by water, as seen in the conventional liquid absorbent mentioned above. C.O.
This is because the selective absorption performance of 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 (produced here by Kishida Chemical Industry Co., Ltd.) by a sublimation method to remove wood pure substances, and toluene was used by using a commercially available special grade reagent (produced here by Kishida Chemical Industry Co., Ltd.). (manufactured by Wako Pure Chemical Industries, Ltd.) was dehydrated with metallic sodium and then distilled for use. 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), above copper chloride () 0.6 g (6 mmol)
and 1 g of polystyrene with a molecular weight of 2200 were added, and 20 ml of toluene was added to dissolve the mixture. The mixture was heated and kept at 60° C. for 2 hours while stirring on a rotary evaporator. The above nitrogen is commercially available nitrogen (here, 99.999% purity manufactured by Teikoku Sanso Co., Ltd.), and commercially available Molecular Sieve 3A (here, manufactured by Nikka Seiko Co., Ltd.) is added immediately before use. The product was purified by passing it through a packed column. 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 10 g of BET surface area 230 m 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 ( ) and a toluene solution of polystyrene were added. After stirring for 10 minutes, the pressure inside the rotary evaporator was reduced (6 mmHg) and the mixture was left overnight to sufficiently remove toluene and prepare an absorbent. 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 1.4/min using an air pump and passing it over the absorbent. 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 by the gas biuret method. Carbon monoxide absorption is rapid;
The amount of carbon monoxide absorbed after 10 minutes was 1.0 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 above-mentioned commercial product) 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, 1.6 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 2 below. [Examples 2 to 7] The same operations as in Example 1 were performed except that the organic solvent, polystyrene, and inorganic oxide of Example 1 were replaced by those shown in Table 1. The amount of carbon monoxide absorbed is also shown in Table 2.

【table】

[Comparative example 1]

in a 200 ml two-necked eggplant flask under dry nitrogen.
0.8 g (6 mmol) aluminum chloride (), 0.6
g (6 mmol) of copper chloride () and 1 g of polystyrene (molecular weight 2200) were added, dissolved in 20 ml of toluene, stirred using a magnetic stirrer, and heated and kept at 60°C for 2 hours to form a liquid absorbent. was prepared. 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 1 minute was 1.6 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. Then, this absorbent was heated to 26°C while rotating the evaporator to generate 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. As is clear from the above Examples and Comparative Examples, the carbon monoxide absorption and separation agent produced by the method of the present invention is
It has very little deterioration with water and can be stably used for absorption and separation of carbon monoxide for a long period of time.

Claims (1)

[Claims] 1. An organic solvent solution of copper halide (), aluminum halide (), and an organic compound having two or more aromatic rings is brought into sufficient contact with a porous inorganic oxide, and then free organic solvent is removed. A method for producing a carbon monoxide absorbing and separating agent. 2. As an organic compound having two or more aromatic rings,
The method according to claim 1, characterized in that linear polystyrene, a derivative thereof, or a modified product thereof is used which is soluble in an organic solvent. 3. The method according to claim 1 or 2, characterized in that alumina, silica, or silica-alumina is used as the porous inorganic oxide.