JPH0238254B2 - FUHOWATANKASUISOKYUSHUBUNRIZAINOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an unsaturated hydrocarbon absorption/separation agent, and in particular to a method for selectively absorbing unsaturated hydrocarbons,
The present invention also relates to a method for producing the above-mentioned solid separation agent that is less susceptible to water deterioration. Conventionally, as agents for absorption and separation of unsaturated hydrocarbon gases such as ethylene _and propylene, compounds with the formula M〓M〓 -A group metal, X: halogen, aromatic:
A liquid absorbent consisting of an aromatic hydrocarbon or halogenated aromatic hydrocarbon solution of a dimetal salt complex of C _6-12 monocyclic aromatic hydrocarbon or halogenated aromatic hydrocarbon −21328), CuAlX ₄
(X: halogen atom)
48-35041), but in all of these, the effective gas absorption ingredients themselves are unstable, and the absorption performance deteriorates in a short period of time, especially if moisture is present in the gas to be treated. There were flaws. In addition, recently, the above-mentioned liquid or solid complexes made of silver halide, aluminum halide (), and polystyrenes have been announced as polymeric metal complexes that have the ability to separate ethylene from mixed gases (Nihon Chemical Industry Co., Ltd.). (See ``Polymer-metal complexes with ethylene separation function'' by Hirai et al., Autumn Annual Meeting 2I03, 1988). However, like the unsaturated hydrocarbon absorbent described above, this complex is highly susceptible to moisture deterioration in a liquid state, and cannot stably absorb and separate ethylene for a long period of time. Further, even in a solid state, there are problems in that water resistance is low and the amount of silver halide and aluminum halide (2) that can be supported is small. The present invention eliminates these drawbacks and proposes a method for producing a solid unsaturated hydrocarbon absorption and separation agent that has highly selective absorption and separation performance for unsaturated hydrocarbons and has extremely low deterioration with water. It is something to do. That is, the present invention provides a method for producing an unsaturated hydrocarbon absorbing and separating agent, which is characterized in that an organic solvent solution of silver halide and aluminum halide (2) is brought into sufficient contact with porous alumina, and then free organic solvent solution is removed. It is about the method. In addition, unsaturated hydrocarbons in the present invention include olefins such as ethylene, propylene, butene,
It is a general term for dienes such as butadiene and unsaturated hydrocarbons such as acetylenes (hereinafter referred to as ethylenes). As the halogen of the silver halide in the method of the present invention, chlorine, bromine, iodine, and fluorine are all effective, but silver 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 silver 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, in the absorption/separation agent obtained by the method of the present invention, since the desorption operation after absorption of ethylene is usually carried out under heating or reduced pressure, low boiling point solvents or high volatility 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 salt 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 degradability 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 silver halide 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. Incidentally, the ability of the method of the present invention as an absorption/separation agent is that when silver acts in a monovalent state, it exhibits remarkable ethylene selectivity and absorbability. Aluminum halide () has the function of holding silver in a monovalent state, and in particular, both exist in equimolar amounts in the complex salts described below [for example, as AgAlX ₄ (X: halogen, the same applies 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 porous alumina, it is heated for 40 to 60 minutes in the absence of moisture, preferably in an inert gas. °C, 8~
Perform a heating operation for 6 hours. With this heating operation,
A complex salt consisting of Ag(), 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. Silver halide and aluminum halide ()
As mentioned above, the molar ratio is preferably 1:1, and it is desirable that there is no excess aluminum halide (). The concentration of the organic solvent solution may be such that silver halide and aluminum halide (2) can be dissolved therein, and there is no need to dilute it more than necessary. Generally, the total amount of silver halide and aluminum halide () is 5 to 50 wt% based on alumina.
Any concentration and amount of the solution supported may be used. Further, the porous alumina used has the ability to sufficiently disperse silver halide and aluminum halide (2) and to immobilize them together with a portion of the organic solvent. However, it must be something that does not reduce or oxidize Ag () 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, silver 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 Ag () 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 ethylene will be easily deteriorated by water, as seen in the above-mentioned conventional liquid absorbent. 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, manufactured 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, manufactured by Kishida Chemical Industry Co., Ltd.). Hikari Pure Chemical Industries ((
Co., Ltd.) was dehydrated with metallic sodium, distilled and used. As silver 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 m mol) and 0.8 g (6 m mol) of the above silver chloride were added, and 20 ml of toluene was added to dissolve. The mixture was heated and kept at 50°C for 6 hours while stirring by rotating a rotary evaporator. In addition, immediately before using the above nitrogen (here, 99.999% purity manufactured by Teikoku Sanso Co., Ltd.), add commercially available Molecular Sieve 3A (here, manufactured by Nikka Seiko Co., Ltd.). The product was purified by passing it through a packed column. Meanwhile, in another 200ml rotary evaporator,
Commercially available alumina A support (average pore diameter 108 Å, manufactured by Catalyst Kasei Co., Ltd., calcined at 550°C for 3 hours)
After putting 10g of BET (surface area 230m ² /g) into the eggplant flask and thoroughly deaerating the inside of the eggplant flask using a vacuum pump,
Using a dropping funnel, the toluene solutions of aluminum chloride and silver chloride prepared previously were added to the solution. After stirring for 10 minutes, the pressure inside the rotary evaporator was reduced to 6 mmHg, and the solution was allowed to stand overnight to sufficiently remove toluene and prepare an absorbent. The absorbent obtained by this is
It weighed 12.13g. To check the performance of this absorbent, put the absorbent into a 200ml rotary evaporator.
It was connected to a container containing 1 atm of a mixed gas of ethylene and nitrogen (ethylene partial pressure: 0.80 atm, nitrogen partial pressure: 0.20 atm), and while a rotary evaporator was being rotated and agitated, ethylene absorption operation was performed at 26°C. This absorption operation was carried out by circulating a mixed gas of carbon monoxide and nitrogen at a rate of 1.4/mm over the absorbent using an air pump. The mixed gas of ethylene and nitrogen is a commercially available product (here, pure ethylene manufactured by Steel Chemical Industry Co., Ltd.):
79.99%, nitrogen: 20.01%) was purified by passing it through a commercially available deoxygenation tower (manufactured by Nikka Seiko Co., Ltd.) immediately before use. The amount of ethylene absorbed is determined by the gas brewet method.
Measured at 26°C. Ethylene absorption was rapid, and the amount of ethylene absorbed after 10 minutes was 2.0 mmol. The absorbent was then heated to 90° C. at 1 atm to release the absorbed ethylene. 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 ethylene is released at a rate of 0.8/mm.
It was circulated for 10 minutes (hereinafter, this operation is referred to as water treatment). Afterwards, this absorbent was heated to 26°C with a mixed gas of 1 atm of ethylene and nitrogen (ethylene partial pressure 0.80 atm, nitrogen partial pressure 0.20 atm) while rotating the evaporator.
It was combined with a container containing 1 (purified from the above-mentioned commercial product) and circulated over the absorbent using an air pump to perform the ethylene absorption operation again. The absorption of ethylene in this case was also rapid, with 2.9 mmol of ethylene absorbed after 10 minutes. The absorbent was then heated to 90° C. at 1 atm to release the absorbed ethylene. After that, the above water treatment, absorption and release are repeated,
The amount of ethylene absorbed was measured. The results are shown in Table 3 below. Examples 2 to 4 The same operations as in Example 1 were performed except that the carriers shown in Table 1 were used in place of the alumina A carrier fired at 550°C in Example 1. The amount of ethylene 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 shown in Table 3.

【table】

[Table] Example 8 The same absorbent as in Example 1 was prepared, and the mixed gas to be absorbed was 1 atm instead of ethylene and nitrogen.
Mixed gas of acetylene and nitrogen (acetylene partial pressure
The same adsorption/desorption experiment was repeated with a nitrogen partial pressure of 0.78 atm and a nitrogen partial pressure of 0.22 atm), and the results shown in Table 4 were obtained.

[Table] The mixed gas of acetylene and nitrogen is commercially available acetylene (100% pure one manufactured by Japan Special Gas Co., Ltd.)
and commercially available nitrogen (same as the one from Teikoku Sanso Co., Ltd. used in Example 1), and purified by passing it through a deoxidizing tower in the same manner as in Example 1 immediately before use. . Comparative Example 1 In a 200ml two-neck eggplant flask under dry nitrogen.
0.8g (6m mol) aluminum chloride (), 0.8
g (6 mmol) of silver chloride was added thereto, 20 ml of toluene was added to dissolve it, and the mixture was heated and kept at 50° C. for 6 hours while stirring using a magnetic stirrer to prepare a liquid absorbent. Put the above liquid absorbent into a 200 ml two-necked eggplant flask, and add 1 atm of a mixed gas of ethylene and nitrogen (ethylene partial pressure 0.80 atm, nitrogen partial pressure 0.20 atm).
(Using the same purified commercial product as in Example 1,
The same applies hereinafter) was combined with a container containing 1 and stirred using a magnetic stirrer to absorb ethylene at 26°C. The mixed gas of ethylene and nitrogen was circulated at 1.4/min and passed over the absorbent using an air pump. The amount of ethylene absorbed was measured at 26℃ using the gas piuret method.
It was measured with Ethylene absorption was rapid, and the amount of ethylene absorbed after 10 minutes was 3.8 mmol. The absorbent was then heated to 90°C at 1 atm to release the absorbed ethylene. On the other hand, combine a container containing nitrogen gas (purity 99.999% (used the same purified commercial product as in Example 1) and an air washing bottle containing distilled water, and use an air pump to pump nitrogen gas into the air washing bottle. 26℃ by passing it through
Water (20,000 ppm) at a saturated vapor pressure of 20,000 ppm was mixed into the nitrogen gas, and the gas was circulated at 0.8/min for 10 minutes over the absorbent after ethylene release. After that, this absorbent was heated to 26°C while rotating the evaporator, and a mixed gas of 1 atm of ethylene and nitrogen (ethylene partial pressure: 0.80 atm, nitrogen partial pressure: 0.20 atm) was applied.
was connected to a container containing ethylene, and an air pump was used to circulate it over the absorbent to absorb ethylene again. The amount of ethylene absorbed at this time was 0.6 mmol. As is clear from the above Examples and Comparative Examples, the ethylene 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 ethylene for a long period of time.

Claims (1)

[Claims] 1. An unsaturated hydrocarbon absorption/separation agent characterized in that an organic solvent solution of silver halide and aluminum halide (2) is brought into sufficient contact with porous alumina, and then free organic solvent is removed. Production 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.