JPH0639402B2 - Adsorption separation of unsaturated hydrocarbons - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for adsorbing and separating an unsaturated hydrocarbon contained therein from an unsaturated hydrocarbon-containing gas, and an unsaturated hydrocarbon adsorbing / separating agent used therefor.

[Prior art]

As an agent for adsorbing and separating unsaturated hydrocarbon gas such as ethylene and propylene, a compound of formula MMX / aromatic (M: Cu or other Group IB metal, M: A or other Group II-A metal, X: halogen, aromatic: C ₆ ~ ₁₂ monocyclic aromatic hydrocarbons or halogenated aromatic hydrocarbons) in the bimetallic salt aromatic hydrocarbon or halogenated aromatic liquid absorbent consisting of a hydrocarbon solution of the complex (JP-A-57-21328), CuAX
Bimetallic salt having ₄ (X: halogen atom) (Japanese Patent Publication No. 48-
No. 35041) has been proposed.

Further, recently, as a polymer metal complex having the ability to separate ethylene from a mixed gas, the above liquid or solid complex consisting of silver halide, aluminum halide and polystyrene has been announced (Chemical Society of Japan Showa 58). 2103 Hirai et al., "Polymer-metal complex with ethylene separation function").

However, since all of the above separating agents use an unstable metal halide complexed with a benzene nucleus as an unsaturated hydrocarbon absorbing component, the stability is remarkably inferior, and particularly moisture in the gas to be treated is If it exists, there is a drawback that its absorption performance deteriorates in a short time. Further, in such a separating agent, the absorbed unsaturated hydrocarbon must be desorbed from the separating agent by heat, and it is difficult to carry out the desorption under reduced pressure. In addition, the separating agent is highly corrosive to metals, and has a drawback of corroding the device used in a short period of time.

〔Purpose〕

The present invention provides a solid unsaturated hydrocarbon adsorption separating agent in which the above-mentioned drawbacks of the prior art are overcome, and the adsorption separation agent is used to adsorb unsaturated hydrocarbons contained therein from a gaseous substance. The purpose is to provide a method of separation.

〔Constitution〕

According to the present invention, as a first invention, an unsaturated hydrocarbon-containing gas is used as an adsorbent (hereinafter referred to as a complex) in which cuprous halide is stably complexed with a non-zeolitic acidic oxide. After contacting and adsorbing the unsaturated hydrocarbon on the composite, the unsaturated carbon adsorbed on the composite by holding the composite under conditions of lower pressure or higher temperature than during adsorption A method for adsorptive separation of unsaturated hydrocarbons, characterized by desorbing hydrogen, is provided, and as a second invention, an unsaturated compound obtained by stably complexing cuprous halide with a non-zeolitic acidic oxide. A hydrocarbon adsorption separating agent is provided.

The unsaturated hydrocarbon adsorption separating agent of the present invention (hereinafter also simply referred to as a separating agent) is a complex of cuprous halide and a non-zeolitic acidic oxide. The non-zeolitic acid oxide has substantially no micropores of about several angstroms, and has an acid point that is either a Bronsted acid point that is stable at low temperature or a Lewis acid point that is easily generated at high temperature. is there. Specific examples of such a non-zeolitic acid oxide include alumina, silica, silica-alumina and the like. Further, as the alumina, γ-alumina obtained by dehydrating and firing a pseudo-boehmite structure obtained from a hydrosol of aluminum is preferable, and 11
Those fired in the air at a high temperature of 00 ° C or higher or steam-treated at 800 ° C or higher are not so preferable, and activated alumina obtained from aluminum hydroxide having high crystallinity is also not so preferable. Similarly, with respect to silica and silica-alumina, those prepared from those in which the colloidal particles of the sol do not grow large are preferable. Zeolitic pores such as zeolite, those having micropores such as activated carbon, and other having molecular sieve capacity, since the solution of cuprous halide is difficult to enter the inner surface of the pores, It is not suitable for separation by adsorption / desorption operation at room temperature because unsaturated hydrocarbons cannot sufficiently exhibit high selective absorption, and such fine pores tend to physically adsorb unnecessary components.

In the non-zeolitic acidic oxide as described above used in the present invention, it is also important to adjust the pore volume, if the pore volume is too small, the Cu (I) inside the pores and the raw material gas The contact efficiency is lowered and the adsorption ability is lowered. Further, as the pore volume increases, the amount of unabsorbed raw material gas (low-concentration unsaturated hydrocarbon gas) remaining in the pores increases, which causes the purity of the recovered product gas to decrease. Therefore, the non-zeolitic acidic oxide used in the present invention has a preferable range of pore volume, and in the case of the present separating agent, the pore volume is 0.2 cc / g to 1.5 cc / g, preferably 0.3 cc / g.
~ 1.0 cc / g. Further, there is a preferable range for the pore size as well as the pore volume, and when the pore size is too small, the molecular sieving ability is expressed, and O ₂ , H ₂ O, C
O _{2 and the} like are easily adsorbed, and the pores may be crushed during the formation of a composite with cuprous halide. Therefore, it is necessary to use an oxide having an average pore size of 20 Å or more before preparation. Further, if the pore volume is the same, the surface area decreases as the pore diameter increases, but in order to uniformly disperse and carry cuprous halide, a high surface area is preferable. For the above reasons, the average pore diameter (diameter) of the acidic oxide is preferably 20 Å or more and 200 Å or less, more preferably 50 Å or more and 150 Å or less.

Conventionally known techniques can be applied as the method for forming a composite of the cuprous halide and the non-zeolitic acid oxide in the present invention. That is, it can be produced by dissolving cuprous halide in a solvent and impregnating or immersing it in an acidic oxide. At that time, it is possible to use water for the preparation of the cuprous halide solution, but it is not efficient because the solubility of the cuprous halide in water is small, and repeated loading with a dilute solution is necessary. As a method of increasing the solubility of cuprous halide, there are a method of forming an acidic solution of hydrochloric acid and a method of adding aluminum halide as a dissolution aid to form a copper complex with an organic solvent. The solid adsorption separation agent of the present invention can be produced by any method.

According to the research conducted by the present inventors, the non-zeolitic acidic oxide includes: a) a step of obtaining an alumina hydrogel from an alumina hydrogel-forming substance; b) the pH of the alumina hydrogel is set to an alumina hydrogel dissolution region and a boehmite gel precipitation region. Alternating with the above, and at the time of changing the pH to at least one of the alumina hydrogel dissolution region and the boehmite gel precipitation region, adding an alumina hydrogel-forming substance to obtain a crystal-grown alumina hydrogel, and / or alumina. Step of adding alumina hydrogel-forming substance in a continuous flow or an intermittent flow while maintaining the boehmite gel in the boehmite gel precipitation region to obtain a crystal-grown alumina hydrogel, c) washing, drying or firing the crystal-grown alumina hydrogel By the combination operation of It has been found that the use of alumina formed by a combination of alumina xerogel or a process of obtaining alumina is preferred. This alumina has substantially no micropores having a diameter of several angstroms, and therefore has no molecular sieving ability and has either a Bressted acid point that is stable at low temperature or a Lewis acid point that is easily generated at high temperature. Since it has acid sites, large pore size, and high surface area, it has the ability to support cuprous halide in a highly concentrated and uniform manner.

Furthermore, this alumina has the property of retaining the cuprous halide without significantly changing the coordination state around the cuprous halide. As a result, the supported and dispersed cuprous halide is kept stable. Then, this stable alumina composite containing cuprous halide exhibits its high selectivity as it is without lowering the chemical absorption capacity of the cuprous halide.

According to the combination of the specific steps as described above, the pore volume is 0.3
Alumina having physical properties of ~ 1.2 cc / g, especially 0.5-0.9 cc / g and average pore size (diameter) 50-150 angstrom, especially 100-130 angstrom, can be easily prepared. , Which is advantageously used as the non-zeolitic acid oxide in the separating agent of the present invention. This alumina is usually used as a molded body. The shape of the molded body can be formed into any shape such as a columnar shape or a spherical shape. Therefore, it can be appropriately selected according to the usage conditions. Generally, a cylindrical molded body having a diameter of 1/16 inch or 1/32 inch is used.

In addition, when the alumina is used as a raw material for the separating agent in the present invention, its chemical properties are also important characteristics. This chemical property generally differs depending on the difference in the preparation method. For example, even when the same raw material is used, different production methods such as precipitation method, aging method, and sintering method are used. When it is produced by using it, the acidity, acid strength distribution, etc. of the obtained alumina are different. This property has a great influence on the preparation of the separating agent of the present invention, and when the cuprous halide is supported, there is a difference in the supporting ability and dispersibility, so that it is necessary to control it appropriately. Conventionally, a method for producing a porous alumina molded body is to produce an alumina hydrogel which is a seed from an alumina hydrogel-forming substance which is a precursor for producing an alumina hydrogel, grows the crystal particles thereof, and converts them into a sol or a gel-like substance. And then wash,
In general, the desired porous alumina molded body is manufactured by a process such as dehydration molding, drying, and firing. In this manufacturing operation, an important step for controlling the chemical properties is to obtain a sol or gel substance. Conventionally, alumina is used as seeds in the gelation process in which the alumina hydrogel that forms seeds is produced from the alumina hydrogel-forming substance that is a precursor that forms the porous alumina molded body, and this alumina hydrogel is grown to obtain these gel-like substances. The method of forming the hydrogel includes a precipitation method, a uniform precipitation method, a hydrolysis method and the like. In the precipitation method, a compound containing aluminum is neutralized with an acid or an alkali to produce an alumina hydrogel which becomes seeds. Further, the homogeneous precipitation method is broadly included in the precipitation method, and overcomes the drawback of the precipitation method, that is, the point that the alumina hydrogel that becomes the seed is non-uniform because the neutralization operation is difficult to control. Using an organic compound such as urea or hexamethylenetetramine as a solvating agent,
The feature is that the neutralization operation becomes slow. The hydrolysis method is a method of producing an alumina hydrogel by hydrolyzing an aluminum compound without using a neutralizing agent. Any of these methods can be used in the step a) of obtaining the alumina hydrogel from the alumina hydrogel-forming substance in the above-mentioned alumina production step, but an unnecessarily complicated method is used in combination with the following step b). Since it is not preferable to use it, it is sufficient to use the precipitation method by a simple neutralization operation. But,
When a method of adding the alumina hydrogel-forming substance in a continuous flow or an intermittent flow while maintaining the alumina hydrogel in the alumina hydrogel precipitation region in step b) is used, the seeded alumina hydrogel is prepared by the precipitation method in step a). When used, it is necessary to adopt a method for uniform production. This is because in such a method, the effect of making the alumina hydrogel of non-uniform particles uniform is insufficient, so that the desired alumina cannot be obtained. Conventionally, the alumina hydrogel obtained from the step a) is supplied as it is or after being aged as a sol or a gel-like substance to the steps such as dehydration and drying. However, this method gives an alumina excellent in adsorption separation performance. Absent.

In addition, in order to adjust the above-mentioned properties of alumina, it is necessary to adjust the basic particles, but regarding the method of controlling the pore structure such as the pore diameter, pore volume and pore diameter distribution of the alumina, the present application A person has already disclosed it in Japanese Patent Laid-Open No. 56-120508. That is, in a method for producing a porous inorganic oxide from a hydrogel-forming substance as a raw material, (1) a step of obtaining the seed hydrogel from the hydrogel-forming substance, and (2) the pH of the hydrogel is set to a hydrogel dissolution region and a hydrogel precipitation. Hydrogels that are alternately grown to and from the region, and when the pH is changed to at least one of the hydrogel dissolution region and the hydrogel precipitation region, a hydrogel-forming substance is added, and finally a crystal is grown to a size that matches the target size. Has revealed how to get.
By this method, it is possible to obtain a gel in which the basic particles are relatively aligned in the target size. Further, the applicant of the present invention discloses that alumina hydrosol having fibrous basic particles is disclosed in
Further, as disclosed in JP-A-55-27830, regarding an alumina hydrosol comprising boehmite particles which are fibrous basic particles having very uniform particles, JP-A-58-213
No. 632 is disclosed. In addition, the present inventors
Relating to a method for obtaining a crystal-grown alumina hydrogel by adding an alumina hydrogel-forming substance in a continuous flow or an intermittent flow while maintaining the alumina hydrogel in the boehmite gel precipitation region, JP-A-58-190823 and JP-A-59 -97526
The technology is clarified in Japanese Patent Publication No. 60-54917 and Japanese Patent Application No. 60-54917. The present inventors have studied the preparation of porous alumina having properties that meet the purpose of the present invention using such a technique, and found that the pH of the alumina hydrogel was between the alumina hydrogel dissolution region and the beammite gel precipitation region. A step of adding alumina hydrogel-forming substance and / or obtaining a crystal-grown alumina hydrogel during the pH change to at least one of the alumina hydrogel dissolution region and the boehmite gel precipitation region while alternately changing the boehmite gel By including the step of adding an alumina hydrogel-forming substance in a continuous flow or an intermittent flow while maintaining it in the precipitation region to obtain an alumina hydrogel crystal-grown to a size that gives the desired specific properties, by including it in the separating agent manufacturing step. I found that the purpose could be achieved. That is, the pore volume of alumina obtained by such a step is in the range of 0.3 to 1.2 cc / g, particularly 0.5 to 0.9 cc / g, and the average pore size is 50 to 150 angstrom, particularly 100
When adjusted to the range of ~ 130 angstroms, the surface area of the obtained alumina becomes very large, and
It was found that by supporting cuprous halide on this alumina, an unsaturated hydrocarbon adsorption / separation agent having a very high capacity can be obtained. It is considered that this is because not only the pore structure of the alumina but also the chemical properties of the surface of the alumina play an important role in combination with the cuprous halide. In order to support the cuprous halide on the alumina, it is sufficient to bring the solution containing the cuprous halide into contact with the alumina and then remove the solvent. In this case, as the cuprous halide solution, one that keeps the copper ions of the cuprous halide stable at a monovalence is used. For example, an aqueous solution containing cuprous halide and hydrogen halide or water A mixed solution of a cuprous halide and a salt that dissolves to dissociate protons and halogen ions, a solution of cuprous halide in an aromatic organic solvent with aluminum halide as a dissolution aid, and the number of carbon atoms in cuprous halide Examples thereof include lower alcohol solvent solutions 1 to 4 and tetrahydrofuran solvent solutions.

Next, the manufacturing process of the alumina will be described in detail.

[Alumina hydrogel-forming substance]

The alumina hydrogel-forming substance used in the production of this alumina is a compound containing aluminum as an element. For example, metallic aluminum (A), aluminum chloride _{(AC 3, AC 3 · 6H} 2 O), aluminum nitrate _{[A (NO 3) 3 · 9H} 2 O ], aluminum sulfate _{[A 2 (SO 4) 3,} A 2 (SO ₄ ) ₃
.18H ₂ O], polyaluminum chloride {[A ₂ (O
H) _nC 6 -n] m (1 <n <5, m <10)}, ammonium alum _{[(NH 4) 2 SO 4 ·} A (S
O ₄ ) ₃ / 24H ₂ O], sodium aluminate (NaA
O _2), aluminate potassium _(KAO 2), aluminum isopropoxide {A _{[OCH (CH 3) 2) 3} },
Ethoxide _{[A (OC 2} H _{5) 3],} aluminum · t-butoxide {A [OC (C
H _{3) 3] 3},} aluminum hydroxide [A (O
H) ₃ ] etc. Preferably, an aluminum salt, e.g., aluminum chloride _(AC 3, AC 3 · 6H
₂ O) of aluminum nitrate _{[A (NO 3) 3} · 9H
₂ O], aluminum sulfate [A ₂ (SO ₄ ) ₃ , A
₂ (SO ₄ ) ₃ · 18H ₂ O], aluminates such as sodium aluminate (NaAO ₂ ), and aluminum hydroxide [A (OH) ₃ ].

[Production of Seed Alumina Hydrogel] [Step a] The seed alumina hydrogel is formed using the above-mentioned alumina hydrogel-forming substance. The particles contained in the seed alumina hydrogel (alumina hydrogel particles) are used as seeds for adding the alumina hydrogel-forming substance to produce crystal-grown alumina hydrogel in the subsequent step [step b)] of obtaining crystal-grown alumina hydrogel. Therefore, in the alumina hydrogel,
Present in the form of hydroxide. This seed alumina hydrogel is generally manufactured according to a conventionally known method. That is, a common method such as a precipitation method, a uniform precipitation method, an ion exchange method, a hydrolysis method and a metal dissolution method can be adopted. In this case, the precipitation method is a method of neutralizing the alumina hydrogel-forming substance with an acidic or alkaline solution. For example, ammonia, sodium hydroxide or the like as a neutralizing agent is added as a solution to a solution of aluminum nitrate or aluminum sulfate, or hydrochloric acid, sulfuric acid or nitric acid is added as a neutralizing agent to a solution of an alkali metal salt or an ammonium salt. Neutralize and convert to aluminum hydroxide. Specifically, it includes a method by a neutralization reaction using a combination of a solution of aluminum nitrate and sodium aluminate. The homogeneous precipitation method is the same as the above-mentioned precipitation method in principle, but is different in that the neutralizing agent concentration during neutralization is kept uniform and the precipitation is carried out uniformly.
For example, when performing uniform precipitation from a solution containing an alumina hydrogel-forming substance in the form of an acidic salt, urea as a neutralizing agent,
An ammonia-releasing substance such as hexamethylenetetramine is used. Specifically, the required amount of urea is dissolved in a solution containing aluminum nitrate or aluminum sulfate, the mixed solution is gradually heated with stirring, the neutralizing agent is gradually decomposed to release ammonia, and this release A method of gradually neutralizing an aluminum salt with ammonia to convert it into an alumina hydrogel is included. The ion exchange method is a method in which cations or anions that coexist in a solution of an alumina hydrogel-forming substance are ion-exchanged by using an ion exchange resin to form a colloidal gel. What is called commercially available colloidal alumina is usually manufactured by these methods. The hydrolysis method is a method in which a hydrolyzable alumina hydrogel-forming substance is added to water to cause a hydrolysis reaction to generate an alumina hydrogel. Specifically, the reaction of an alcohol solution of aluminum isopropoxide is included. As a metal dissolution method, there is a method in which basic aluminum hydroxide is generated by adding aluminum metal powder to boiling aluminum nitrate or an aluminum nitrate solution.

As described above, the alumina hydrogel to be the seed can be obtained by various methods familiar to those skilled in the art.
That is, step a) is well known to those skilled in the art, and is not limited by the above-mentioned matters. The kind of hydrogel-forming substance used as a starting material, etc. should be considered in consideration of factors such as economic efficiency. It can be selected appropriately. In some cases, it is possible to use a commercially available alumina hydrogel as it is, or to prepare it in a combination of an alumina hydrogel-forming substance used in obtaining the crystal-grown alumina hydrogel in step b) and a pH-unchanging regulator. is there. In this case, there is an advantage that step a) and step b) can be performed in a continuous operation without a complicated operation such as a separation operation, that is, step a) and step b) are the same reagent. Can be performed under the same conditions. The concentration of the alumina hydrogel to be the seeds is not particularly limited, but it may be within a range such that the whole is stirrable and does not hinder the execution of step b), and is usually 10% by weight or less, particularly 0.1 to 5% by weight. %.

[Step of Obtaining Crystal-Grown Alumina Hydrogel] [Step b)] This step is carried out on the alumina hydrogel to be the seed obtained in the step a] under pH fluctuation and / or control,
The step of adding an alumina hydrogel-forming substance and growing crystals of the alumina hydrogel is included. In this step, the alumina hydrogel basic particles can be grown very uniformly and controlled to a target size. In this step, the pH of the seed alumina hydrogel obtained in the step a) is alternately changed between the alumina hydrogel dissolution region and the boehmite gel precipitation region, and at least one of the alumina hydrogel dissolution region and the boehmite precipitation region. When the pH changes to the region of, the alumina hydrogel-forming substance is added to obtain a crystal-grown alumina hydrogel, and / or the alumina hydrogel-forming substance is kept in the boehmite gel precipitation region to form a continuous flow or an intermittent flow. Added
Obtaining a crystal-grown alumina hydrogel is performed. In the case of operation under pH fluctuation, as one of preferred methods, only when changing to the boehmite gel precipitation region, the above-mentioned alumina hydrogel-forming substance or pH adjusting agent is added alone or in the form of a mixture, and a boehmite gel is prepared. Get a precipitate. In this case, the alumina hydrogel means not only boehmite but also general alumina hydrogel such as bayerite and amorphous alumina hydrogel. In addition, boehmide gel is composed of fine boehmite crystallites which are in a maintenance state among alumina hydrogels, and when these crystallites aggregate, they form remarkably sparse aggregates as compared with other alumina hydrogels. Therefore, the alumina obtained by drying and calcining this has a remarkably high surface area and a metal species supporting ability. In the case of operation while maintaining the pH, one of the preferred methods is to obtain a boehmite gel precipitate by using one in which at least one of the alumina hydrogel-forming substance and the pH adjusting agent substantially contains a sulfate group. is there. As used herein, the alumina hydrogel dissolution region refers to a pH of 5 or less or 11 or more, and the boehmite gel precipitation region refers to a pH of 6 to 11. That is, the alumina hydrogel dissolution region is a pH region where the alumina hydrogel fine particles can be solubilized, and the boehmite gel precipitation region is a pH region under the condition where the growth of boehmite microcrystallites can be caused. Therefore, the crystal growth operation of alumina hydrogel under pH fluctuation and the crystal growth operation of alumina hydrogel under pH maintenance are completely different in principle, and conceptually, there is a completely opposite part. That is, when the pH is changed, in order to change the pH more effectively, the presence of polyvalent ions and a high concentration of dissolved salt are likely to act as an inhibitor. However, in order to keep the pH within a certain range, the presence of dissolved salts creates a buffering effect,
The presence of multiply charged ions is also believed to have the positive effect of catalyzing crystal growth.

Under pH fluctuation, in the boehmite gel precipitation area, the fine alumina hydrogel particles dissolved in the alumina hydrogel dissolution area and the alumina hydrogel-forming substance added during pH fluctuation are rapidly occluded in large hydrogel particles, that is, boehmite microcrystallites. , The crystals grow to a larger alumina hydrogel, while the mixed fine alumina hydrogel particles are dissolved in the alumina hydrogel dissolution region, and the remaining particles of the alumina hydrogel are homogenized. On the other hand, under the condition that the pH is maintained, the uniform seed alumina hydrogel is subjected to the conditions controlled in the boehmite gel precipitation region, that is, the alumina hydrogel is uniformly occluded in the hydrogel particles. The homogenization of the particles of the crystal-grown alumina hydrogel produced by adding the forming substance is realized. That is, in step b), the pH of the hydrogel with respect to the seed alumina hydrogel.
By varying or / and maintaining the pH and adjusting the addition of the alumina hydrogel-forming material,
A precipitate of alumina hydrogel particles having a uniform particle size is obtained. In short, when the particles of alumina hydrogel are non-uniform, it is possible to repeatedly and alternately fluctuate the reaction system between dissolution conditions and growth conditions by utilizing the property that the particles are more likely to be dissolved and grow easily. , Or when the alumina hydrogel particles are uniform, it is difficult to generate secondary nuclei, and the conditions under which the particle growth is uniform, that is, the alumina hydrogel-forming substance is maintained while maintaining the pH at a preferable addition rate. By introducing into the system, a uniformly grown alumina hydrogel of seed alumina hydrogel is obtained. The change to the dissolution area of the alumina hydrogel or the precipitation area of the boehmite gel, or the retention thereof is performed using a pH adjusting agent. As the pH adjuster, an alumina hydrogel-forming substance itself or a non-alumina hydrogel-forming substance may be used.
However, in the case of fluctuation or retention in at least one region, the pH adjusting agent used is preferably the alumina hydrogel-forming substance itself. More preferably, under pH fluctuation, the alumina hydrogel-forming substance is used as a pH adjusting agent only when the pH changes to the boehmite gel precipitation region, and in the operation while maintaining the pH, at least one of the alumina hydrogel forming substance and the pH adjusting agent is used. Substantially contains sulfate radicals. That is, since most of the alumina hydrogel-forming substances show acidity or alkalinity in a state of being dissolved in water, they can be used as a pH adjusting agent. For example, those exhibiting acidity include aluminum chloride, aluminum nitrate, aluminum sulfate, etc., those exhibiting alkalinity include sodium aluminate, etc., and those containing sulfate include aluminum sulfate, Is also one of those exhibiting acidity. Examples of the pH adjusting agent composed of a non-alumina hydrogel-forming substance include acids such as hydrochloric acid, nitric acid and sulfuric acid, alkalis such as sodium hydroxide and aqueous ammonia, and sulfuric acid containing a sulfate group.

[Conversion of Alumina Hydrogel to Alumina] [Step]] The crystal-grown alumina hydrogel is made into an alumina cellogel by a combined operation of washing and drying, and is then fired to form a porous alumina compact having a desired shape and characteristics. It is said that
In order to remove coexisting unnecessary ions or impurities, a washing operation is performed depending on the state of the alumina hydrogel and / or the state of the alumina xerogel. Conversion from alumina hydrogel to alumina xerogel can be carried out by drying, and this drying method is generally carried out at a temperature of room temperature or higher and 200 ° C. or lower under conditions such that water in the alumina hydrogel is sufficiently evaporated. Firing is generally 300-1200
C., preferably 400 to 800.degree. C., at which .gamma.-alumina is formed. In this process, the alumina molded body is molded in the state of alumina hydrogel or xerogel, or rarely in the state of a fired product. The method may be a gel molding method by adjusting the humidity of alumina hydrogel or a molding method using alumina xerogel powder and a binder. Further, this step is a step of converting alumina hydrogel into alumina, and a conventionally known method can be adopted. The porous alumina molded body thus obtained is advantageously used as a raw material of the separating agent of the present invention, and in particular, by adopting the process b), an alumina molded body having the desired physical properties and chemical properties is obtained. Can be formed.

The separating agent of the present invention can be obtained by carrying out complexing with a cuprous halide on the alumina molded body obtained as described above. In this case, the amount carried is uniform on the surface of alumina. A sufficient amount to cover a single layer is preferred, which depends on the surface area of the alumina, and usually the copper weight is in the range of 0.2 to 0.4 relative to the alumina weight.

The separating agent of the present invention has the property of adsorbing unsaturated hydrocarbons such as ethylene and propylene with good selectivity, and further, the separating agent having adsorbed unsaturated hydrocarbons is heated or kept under reduced pressure to adsorb the adsorbent. It has the property of desorbing the unsaturated hydrocarbons. Therefore, the separating agent of the present invention,
By applying to a gas containing an unsaturated hydrocarbon, for example, a pyrolysis gas of heavy oil or a pyrolysis gas of ethane, unsaturated hydrocarbons such as ethylene contained therein can be selectively separated and recovered.

When the unsaturated hydrocarbon contained in the gaseous substance is separated and recovered using the separating agent of the present invention, any of the temperature fluctuation method and the pressure fluctuation method can be adopted. When used in the temperature fluctuation method, it is preferable to contact the unsaturated hydrocarbon-containing gas with the separating agent of the present invention at a temperature as low as possible. In order to desorb the adsorbed unsaturated hydrocarbons from the separating agent, the temperature is higher than the adsorption treatment temperature. The larger the temperature difference, the larger the desorption amount of the adsorbed gas. Therefore, the temperature difference may be selected according to the desired recovery amount. The adsorption / desorption treatment temperature can be appropriately selected. Generally, adsorption treatment is performed at a temperature of 5 to 100 ° C.
Desorption process at a temperature of ~ 150 ° C.

Further, in the pressure fluctuation method, adsorption and desorption are carried out by treating the unsaturated hydrocarbon-containing gas with the adsorbent of the present invention with a pressure difference. Adsorption is performed on the high pressure side of pressure fluctuation, and desorption is performed on the low pressure side. After pressurizing and adsorbing, desorption may be performed by returning to normal pressure, or desorption may be performed after adsorbing at normal pressure and depressurizing. In this case, the pressure difference is selected according to the amount of unsaturated hydrocarbon recovered. The recovery amount increases as the pressure difference increases. Further, the temperature fluctuation method and the pressure fluctuation method can be combined.

〔effect〕

The separating agent of the present invention is different from the conventional separating agent in that the adsorptive capacity is not significantly deteriorated by water.
The adsorption / desorption treatment can be carried out by the pressure fluctuation method, and since the metal corrosiveness is small, the apparatus to be implemented is not corroded in a short period of time.

〔Example〕

 Next, the present invention will be described in more detail with reference to Examples.

The pore size distribution shown below was determined by the so-called mercury porosimetry method using Mercury, Pressure, and Porosimeter Model 70 (manufactured by Carlo Erba Co., Milan, Italy). The surface tension of mercury is 474 dyn at 25 ℃.
e / cm, contact angle 140 ° C, absolute mercury pressure 1 to 200
The measurement was performed while changing the pressure to 0 kg / cm ² . Further, as cuprous chloride used in the following, a commercially available special grade reagent (manufactured by Wako Pure Chemical Industries) was used as it was, and as aluminum chloride, a PCB quantitative reagent (manufactured by Wako Pure Chemical Industries) was used as it was.

Example 1 1 NHC 40 m in a 200 m two-necked eggplant flask under dry nitrogen
Then, 0.6 g (6 mmo) of cuprous chloride was added, and the mixture was heated and kept at 70 ° C. for 2 hours to obtain an unemployed transparent solution. On the other hand, as a non-zeolitic porous acidic oxide, a commercially available alumina carrier (manufactured by Sumitomo Alumina Co., Ltd.) that was calcined at 550 ° C. for 3 hours
Average pore diameter 88Å, BET surface area 265m ² / g, particle size 2-4mm
10 g of (spherical) and prepare the above CuC under a stream of dry nitrogen.
-Added to the aqueous HC solution. After soaking at 70 ° C. for 30 minutes, the inside of the eggplant flask was evacuated under reduced pressure (about 10 mmHg) for 3 hours by an aspirator to sufficiently remove the solvent to obtain a light gray adsorption separating agent. A gas mixture of ethylene at 25 ° C and 1 atm (0.3 atm of ethylene partial pressure and 0.7 atm of nitrogen partial pressure) was passed through this adsorption / separation agent, and its adsorption performance was confirmed to be 3.0 mmo in 10 minutes.
Was the adsorption amount of. Next, decompress the system with a vacuum pump (approx.
15mmHg) and kept for 10 minutes, ethylene 2.3mmo
Recovered. Further, nitrogen gas containing water having a saturated vapor pressure for adsorption / separation was blown. After that, the mixed gas was ventilated again, and the adsorption amount was measured, and the adsorption amount was 2.
It was 1 mmo. In addition, depressurize this adsorption separator (about 15 mmH
g), hold for 10 minutes, then mix the above gas again at 25 ° C.
It was 2.1 mmo when the amount of adsorption was measured by ventilating with
No deterioration in water absorption and absorption was observed.

Example 2 The adsorbent separating agent used in Example 1 was used as it was, and a sufficient amount of a raw material gas having the following composition was aerated under the conditions of 25 ° C. and 1 atm. The adsorption amount was 2.6 mmo.

_{C 2 H 4: 40vo% C} 2 H 6: 40vo% N 2: 20vo% Next, the inside of the system pressure was reduced with a vacuum pump (about 15 torr), the desorbed gases is recovered, analyze the gas composition by gas chromatography did. The recovered gas was 2.7 mmo and its composition was as follows.

_{C 2 H 4: 90.3vo% C} 2 H 6: 6.6vo% N 2: 3.1vo% Example 3 Dry under nitrogen cuprous 0.6 chloride 200m2 necked round-bottomed flask
g (6mmo) and aluminum chloride 0.8g (6mmo),
Toluene 20m was added as an aromatic compound and dissolved,
The mixture was heated and kept at 2 ° C. for 2 hours. The solution CuC-AC ₃ -
A black transparent color peculiar to the toluene complex solution was exhibited. Note that the above-mentioned nitrogen is commercially available nitrogen (here, purity 9 manufactured by Teikoku Oxygen Co., Ltd.
Immediately before use, 9.999%) was passed through a column packed with a commercially available molecular sieve 3A (here, manufactured by Nikka Seiko Co., Ltd.) and purified.

Next, as an acidic oxide, an alumina A carrier (average pore diameter 108 manufactured by Catalysts & Chemicals Co., Ltd.) calcined at 550 ° C. for 3 hours was used.
Å, 10g of BET surface area 230m ² / g) was put in a 200m ^2- necked eggplant flask and the inside of the eggplant flask was thoroughly degassed by using a vacuum pump, and then the solution previously prepared using a dropping funnel was added to this. It was Then, decompress the inside of the eggplant flask (6
mmHg), the mixture was allowed to stand for a whole day and night, and toluene was sufficiently removed to obtain an adsorption separation agent. A gas mixture of 1 atm at 25 ° C (ethylene partial pressure: 0.3 atm, nitrogen partial pressure: 0.7 atm) was passed through this adsorbent, and its adsorption performance was confirmed to be 3.0 m in 10 minutes.
It was the amount of mo adsorption. Next, the system was depressurized (15 mmHg) with a vacuum pump and kept for 10 minutes.
4mmo recovered. Furthermore, nitrogen gas containing saturated vapor pressure water was sprayed onto this adsorption separator (H ₂ O aeration rate of about 30 mmo
). Then, when the mixed gas was ventilated again and the adsorption amount was measured, the adsorption amount was 2.3 mmo. After depressurizing (15 mmHg) this adsorbent and keeping it for 10 minutes, the above mixed gas was ventilated again, and the adsorbed amount was measured. The adsorbed amount was 2.2 mmo, and the deterioration of the adsorbing ability due to water was observed. There wasn't.

Example 4 A 11.6 wt% aqueous solution of sulfuric acid 0.15 and deionized water 10 were placed in a enamel jar and heated to 90 ° C., and then vigorously stirred, and an aqueous solution of sodium aluminate having an A ₂ O ₃ concentration of 69 g /.
When 0.39 was charged instantaneously, a slurry-like aluminum hydroxide aqueous solution having a pH of 10 was obtained. Using this as seed aluminum hydroxide, stirring was continued, and after 10 minutes, 0.15 of the above sulfuric acid aqueous solution was added as the first step operation.
Showed 3.5. When this solution was kept stirring at 90 ° C. and stirred for 5 minutes, 0.3 of the aqueous sodium aluminate solution was added, and a pH of 10 was obtained. This operation of alternately adding sulfuric acid and sodium aluminate after a fixed period of time was repeated 8 steps. After that, the slurry was filtered, redispersed in deionized water 10 and filtered and washed three times to obtain a cake. Take out this cake and mold it to 1.6 mmφ with an extrusion molding machine,
The extruded product was dried at 120 ° C. for 6 hours and then calcined at 500 ° C. for 3 hours to obtain alumina B. The properties of this alumina are shown in Table 1.

Table-1 Average Pore Diameter [Å]: 119 Pore Volume [cm ³ / g]: 0.713 Surface Area (m ² / g): 240 Next, under nitrogen, put in a 200 m ^2- neck round bottom flask and cuprous chloride.
0.6g (6mmo) was added, IN hydrochloric acid solution 40 was added, and 70 ℃
The mixture was heated and kept warm for 2 hours to obtain a colorless transparent solution. To this solution, 10 g of the alumina carrier B dried at 120 ° C. for 2 hours was added under a nitrogen stream. After soaking at 70 ° C for 30 minutes, the inside of the eggplant flask was depressurized by an aspirator and exhausted for 8 hours to sufficiently remove water to obtain a light gray adsorption separating agent.

A gas mixture of 1 atm (80% ethylene,
Ethane (20%) was aerated at room temperature, and the adsorption amount was measured by the constant pressure volume method. The adsorption amount was 4.6 mmo. Next, the inside of the system was depressurized (0.1 atm) with a vacuum pump and held for 10 minutes. At that time, when exhaust gas from the vacuum pump was collected and analyzed by gas chromatography, 2.7 mmo of ethylene was recovered.

Further, nitrogen gas containing water having a saturated steam pressure was sprayed onto the adsorption separator (H ₂ O contact amount: about 30 mmo). afterwards,
The mixed gas was passed through the adsorption / separation agent at room temperature, and the adsorption amount was measured. As a result, the adsorption amount was 2.5 mmo. Next, this adsorption / separation agent was decompressed (0.1 atm) with a vacuum pump and kept for 10 minutes, and 2.5 mmo of ethylene was recovered.

Example 5 Cuprous chloride 0.6 in a 200 m 2-neck eggplant flask under dry nitrogen
g and 0.8 g of aluminum chloride were added, 20 m of toluene was added and dissolved, and the mixture was heated and kept at 60 ° C. for 2 hours while stirring.
Next, the alumina carrier B of Example 4 dried at 140 ° C. for 2 hours was cooled in a dry nitrogen atmosphere, and then the above CuC-AC was used.
_3- Added to toluene solution. After soaking for 30 minutes, the inside of the eggplant flask was depressurized (about 6 mmHg) with a vacuum pump and kept for 8 hours to sufficiently remove toluene to prepare an adsorption separator. The mixed gas used in Example 4 was passed through this adsorption / separation agent at room temperature, and its adsorption performance was examined. As a result, the adsorption amount was 4.
It was 9 mmo. Next, decompress the system with a vacuum pump (0.1
Atmospheric pressure) and kept for 10 minutes, ethylene 2.7mmo
Recovered. Nitrogen gas containing saturated water vapor was sprayed onto the adsorption separator (H ₂ O contact amount about 30 mmo).
Then, when the above mixed gas was ventilated at room temperature, the adsorption / desorption amount was 2.6 mmo, and deterioration due to water was not observed.

Example 6 0.05% A ₂ O ₃ concentration of aluminum sulfate aqueous solution
Take 10 mL of deionized water in a porcelain jar and heat to 90 ° C, then stir vigorously to maintain the A ₂ O ₃ concentration of 69
When 350 m of g / sodium aluminate aqueous solution was immediately added, a cloudy, slurried aqueous solution of aluminum hydroxide having a pH of 10 was obtained. Using this as seed aluminum hydroxide, an aluminum sulfate aqueous solution with an A ₂ O ₃ concentration of 8 g / 0.29 hr and a sodium aluminate aqueous solution with an A ₂ O ₃ concentration of 69 g / at a constant rate of 0.20 / hr. Added using a vessel. During the 6 hours that the addition operation was continued, the temperature
It was 90 ° C and pH 9-10. Further, 3 hours after the start of injection, 0.3 sampling liquid was collected, filtered, redispersed in deionized water 2 and filtered to repeat washing three times to obtain a cake. This cake showed pseudo-boehmite on X-ray diffraction. With the solid content of the cake at about 25%
It was molded into a columnar shape by an extrusion molding machine having a die with a hole of 1.6 mmφ and dried at a temperature of 120 ° C. for 6 hours. Then, it was put into an electric furnace and blown with air, and baked at 500 ° C. for 3 hours. The properties of the obtained alumina C are shown in Table 2.

Table-2 Average Pore Diameter [Å]: 108 Pore Volume [cm ³ / g]: 0.722 Surface Area (m ² / g): 266m ² / g Next, using the same method as in Example 4, hydrochloric acid of cuprous chloride A solution was prepared, and 10 g of the above alumina carrier C dried at 120 ° C. for 2 hours was added under a nitrogen stream.After soaking at 70 ° C. for 30 minutes, the pressure in the eggplant flask was reduced by an aspirator for 8 hours. The mixture was evacuated and the water was sufficiently removed to obtain a light gray adsorption separating agent.The adsorption separating agent was aerated with the ethylene mixed gas used in Example 4, and its adsorption performance was confirmed to be 5.1 mmo. Next, when the pressure inside the system was reduced by a vacuum pump (0.1 atm) and kept for 10 minutes,
mmo ethylene was recovered. Further, nitrogen gas containing water having a saturated vapor pressure was blown to the adsorbent separation agent (H ₂ O contact amount about 30 mmo). Then, when the above ethylene mixed gas was ventilated at room temperature, the adsorption / desorption amount was 3.0 mmo, and deterioration due to water was not observed.

In the same manner as in Example 7 Example 5, CuC-AC 3 _- toluene was prepared. To this, 10 g of the alumina carrier C obtained in Example 6 dried at 140 ° C. for 2 hours was added under a dry nitrogen stream. Then, the same procedure as in Example 5 was carried out to obtain a pale gray adsorption separating agent. When the adsorption performance of this adsorption / separation agent was investigated by ventilating the ethylene mixed gas used in Example 4 at room temperature, it showed an adsorption amount of 5.0 mmo. Next, decompress the system (0.
When the pressure was set to 1 atm and kept for 10 minutes, 3.0 mmo of ethylene was recovered.

Further, nitrogen gas containing water having a saturated vapor pressure was blown to the adsorbent separation agent (H ₂ O contact amount about 30 mmo). afterwards,
When the above ethylene mixed gas was ventilated at room temperature, the adsorption / desorption amount was 2.8 mmo, and deterioration due to water was not observed.

Example 8 2.28 0.13 N hydrochloric acid solution and 10 deionized water were placed in a enamel jar and heated to 90 ° C., then with vigorous stirring 0.28 aqueous solution of sodium aluminate with A ₂ O ₃ concentration of 69 g /
Was added instantaneously and, after stirring for 15 minutes, this was used as an aqueous solution of seed aluminum hydroxide, and 0.13 of the above-mentioned hydrochloric acid solution was added as a first step operation. 90 ° C
After 5 minutes while maintaining stirring at 0.degree. C., 0.35 of the aqueous sodium aluminate solution was added, resulting in a pH of 9. The operation of alternately adding hydrochloric acid and sodium aluminate at a fixed time was continued in the second and subsequent steps, and after the 10th step was completed, the mixture was held for 15 minutes to obtain alumina D in the same manner as in Example 4. It was The properties of this alumina D are shown in Table 3.

Table-3 Average Pore Diameter [Å]: 114 Pore Volume [cm ³ / g]: 0.650 With Surface (m ² / g): 228 Next, an adsorption / separation agent was obtained by the same operation as in Example 4, and at room temperature. When the adsorption capacity was examined, the adsorption amount was 4.6 mmo.
When this was depressurized (0.1 atm) with a vacuum pump and kept for 10 minutes, 2.6 mmo of ethylene was recovered. Further, nitrogen gas containing water having a saturated water vapor pressure was blown to this adsorption separator (H ₂ O contact amount about 30 mmo). Then, the amount of adsorption / desorption was measured at room temperature in the same manner as above, and it was 2.6 mmo, and no deterioration due to water was observed.

In the same manner as in Example 9 Example 5, CuC-AC 3 _- toluene was prepared. To this, 10 g of the alumina carrier D obtained in Example 8 dried at 120 ° C. for 2 hours was added under a dry nitrogen stream. Then, the same procedure as in Example 5 was carried out to obtain a pale gray adsorption separating agent. When the adsorption performance of this adsorption separation agent was examined by the same method as in Example 4, the adsorption amount was 4.
It was 7 mmo. Decompress this with a vacuum pump (0.1 atm)
After maintaining for 10 minutes, 2.6 mmo of ethylene was recovered. Further, nitrogen gas containing water having a saturated vapor pressure was blown to the adsorbent separation agent (H ₂ O contact amount about 30 mmo).
After that, when the adsorption / desorption amount was measured at room temperature, it was 2.5 mmo, and no deterioration due to water was observed.

Example 9 _A 2 _{O 3} concentration 80 g / aqueous solution of aluminum sulfate 0.224
And deionized water 10 into a enamel bikini container, 90 ℃
After heating, the concentration of A ₂ O _{3 was} 69 g /
Immediately add 1.55 of aqueous sodium aluminate solution to
Ten slurry white liquids were obtained. This was kept at 90 ° C for 6 hours. At that point the solution had a pH of 10. The liquor was filtered and washed with deionized water to remove most of the Na ⁺ and SO ₄ ²⁻ ions. The obtained filter cake was molded into a 1.6 mmφ by an extrusion molding machine, dried at 120 ° C. for 6 hours, and then baked at 500 ° C. for 3 hours to obtain an alumina molded body E.
The physical properties of this molded product E were as follows.

Table-4 Surface area (m ² / g): 159 Pore volume [cc / g]: 0.31 Average pore diameter [Å]: 78 Using this alumina molded product E10g, the adsorption separation agent was prepared by the method of Example 4. The amount of adsorption was measured in the same manner as in Example 4. As a result, it was found to be 3.2 mmo at room temperature, and 1.4 mmo of ethylene was recovered when this was kept under vacuum pump decompression (0.1 atm) for 10 minutes. In this case, the adsorptive capacity of the adsorptive separating agent was smaller than that of Example 4, but this is considered to be due to the difference in the production of the alumina used.

Claims (3)

[Claims] 1. An unsaturated hydrocarbon-containing gas is brought into contact with a complex of cuprous halide and a non-zeolitic acid oxide to adsorb the unsaturated hydrocarbon, and then the complex is mixed. A method for adsorptive separation of unsaturated hydrocarbons, characterized in that the unsaturated hydrocarbons adsorbed to the complex are desorbed by holding the body under conditions of lower pressure or higher temperature than during the adsorption. . 2. An unsaturated hydrocarbon adsorption / separation agent in which cuprous halide is stably complexed with a non-zeolitic acid oxide. 3. The non-zeolitic acid oxide comprises: a) a step of obtaining an alumina hydrogel from an alumina hydrogel-forming substance; b) alternating pH of the alumina hydrogel between an alumina hydrogel dissolution region and a boehmite gel precipitation region. At the same time, when the pH changes to at least one of the alumina hydrogel dissolution region and the boehmite gel precipitation region, a step of adding an alumina hydrogel forming substance to obtain a crystal-grown alumina hydrogel, or / and the alumina hydrogel to the boehmite gel precipitation region. A step of adding an alumina hydrogel-forming substance in a continuous flow or an intermittent flow while maintaining the temperature to obtain a crystal-grown alumina hydrogel, c) Obtaining an alumina gel or alumina by a combination of washing and drying or firing of the crystal-grown alumina hydrogel Process, The unsaturated hydrocarbon adsorption separation agent according to claim 2, which is alumina formed by the combination of