JPS6258772B2 - - 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, as a gas separation agent, the formula _M〓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, a liquid absorbent consisting of copper halide (2018), aluminum halide (2019), and aromatic hydrocarbons (Japanese Patent Application Laid-Open No. 58-24321),
A solid absorbent made of copper halide (), aluminum halide (), polystyrene (Japanese Unexamined Patent Publication No. 58-49436), copper halide (), aluminum halide (), activated carbon or graphite Solid absorbent (JP-A-Sho
58-124516), steel mills, oil refineries,
A method has been proposed to selectively absorb and separate CO, which is useful as a basic raw material for synthetic chemistry, from CO-containing mixed gases produced by petrochemical plants. 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 deterioration with respect to water. That is, the present invention is characterized in that an organic solvent solution of copper halide () and aluminum halide () is brought into sufficient contact with a porous inorganic oxide (excluding alumina, the same shall apply hereinafter), and then free organic solvent is removed. The present invention relates to a method for producing a carbon monoxide absorption and separation agent. 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. 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 () and aluminum halide (), 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 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 according to 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, but the aluminum halide side of the complex salt is a mixture of the inorganic oxide of the carrier and the organic solvent. This is because it is presumed that hydrophobicity is maintained by a cooperative action, and if this organic solvent evaporates during the above-mentioned desorption operation, hydrophobicity is lost and the deterioration property with respect to water increases. 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 the porous inorganic oxide. The contact method is
Impregnation methods, dipping methods, spraying methods, etc. are employed, and among them, the impregnation method is generally used, in which an amount of solution approximately corresponding to the pore volume of the carrier is sufficient without using an excessive amount of organic solvent. 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 especially in the complex salts described below, both are present in equimolar amounts [for example, as CuAlX ₄ (X: halogen, the same hereinafter)]. 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 minutes in the absence of water, 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(), the organic compound, and X is formed, and the complex salt is also presumed to form some kind of bond with the inorganic oxide of the carrier as described above. And, with this heating operation,
Some 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 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.
Generally, the solution concentration and amount may be such that copper halide (2) and aluminum halide (2) are supported in a total amount of 5 to 50 wt% relative to the inorganic oxide. Furthermore, the porous inorganic oxide used has the ability to sufficiently disperse copper halide (2) and aluminum halide (2) and to immobilize it together with a portion of the organic solvent. 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 calcined at 500-900°C, with BET surface area of 40-400 m ² /g, more preferably 50-350
m ² /g is preferable, and an inorganic oxide that disperses copper (2) and/or aluminum (2) in an ion-exchange manner is selected. Specifically, silica, silica alumina, titania, silica magnesia, zirconia, alumina magnesia, etc. are used, and silica, which exhibits particularly excellent dispersion and supporting ability, is preferred. 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 in the porous inorganic oxide, and free organic solvent is This is because if it remains in the pores in a liquid state, the selective absorption performance of CO will easily deteriorate due to water, as seen in the conventional liquid absorbent mentioned above. The method of the present invention will now 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, commercially available silica gel (manufactured by Fuji Davison, product name ID GEL, BET) was calcined at 800°C.
After thoroughly degassing the inside of the eggplant flask using a vacuum pump, add toluene containing the previously prepared aluminum chloride () and copper chloride ( ⁾ using a dropping funnel. solution was 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. The absorbent obtained by this is
It weighed 11.93g. 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.).
%, _N2 : 21.18%) was purified by passing it through a commercially available deoxidation 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 3.0 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
0.21atm) (purified from the above commercial product) 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, 2.1 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 6 The same operations as in Example 1 were performed except that the inorganic oxides shown in Table 1 were used instead of the silica gel calcined at 800°C in Example 1. The amount of carbon monoxide absorbed is also shown in Table 3 below.

[Table] Examples 7 to 8 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】

[Comparative test on selective absorption capacity]

Regarding the absorbent manufactured in Example 1 and the absorbent manufactured according to the manufacturing conditions of Example 1 using activated carbon (Shirasagi C surface area of Takeda Pharmaceutical Co., Ltd., approximately 1300 m ² /g) in place of silica gel, carbon monoxide A mixed gas consisting of carbon monoxide, carbon dioxide and nitrogen (CO partial pressure 0.71 atm, CO ₂ partial pressure
A comparative test was conducted using N2 partial pressure of 0.10atm and _N2 partial pressure of 0.19atm. 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 1.7 mmol of carbon monoxide and 0.03 mmol of carbon dioxide, but the absorbent using activated carbon absorbed 2.2 mmol of carbon monoxide and 0.03 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 that uses activated carbon instead of silica gel absorbs not only carbon monoxide but also a considerable amount of carbon dioxide, whereas the absorbent of Example 1 uses activated carbon instead of silica gel. It can be seen that the amount of carbon absorbed 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 method characterized in that an organic solvent solution of copper halide () and aluminum halide () is brought into sufficient contact with a porous inorganic oxide (excluding alumina), and then free organic solvent is removed. A method for producing a carbon monoxide absorption and separation agent. 2 Fired at 500-900℃, surface area 50-350
2. A method as claimed in claim 1, characterized in that a porous inorganic oxide (excluding alumina) of m ² /g is used. 3. The method according to claim 1 or 2, characterized in that silica is used as the porous inorganic oxide. 4. The method according to claim 1, 2 or 3, characterized in that an aromatic compound is used as the organic solvent.