JPS61238340A - Preparation of zeolite for dehydration adsorbent - Google Patents

Abstract

PURPOSE:To enhance moisture adsorbing capacity and to suppress side reaction at the time of dehydration treatment, by treating A-type zeolite in an aqueous medium containing an ammonium salt of mineral acid prior to or posterior to granulation. CONSTITUTION:Granulated A-type zeolite is treated in an aqueous medium containing an ammonium salt of mineral acid. During treatment, the concn. of the ammonium salt is usually 1-20wt%, pref., 5-10wt%. As the ammonium salt of the mineral acid, there are ammonium sulfate and ammonium nitrate, etc. The zeolite after treatment is washed with water in order to remove impurity salts and filtered to be dried at about 150-350 deg.C for about 1-5hr. As a separate method, the A-type zeolite slurry prior to granulation may be treated in the same way to be subjected to a granulation means and a baking means.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for producing a zeolite adsorbent for dehydration, and more specifically, it has excellent moisture adsorption performance and suppresses side reactions and side effects during dehydration treatment. The present invention relates to a method for producing granular zeolite for dehydration.

The present invention relates to a method for producing a zeolite adsorbent for dehydration, which is particularly suitable for dehydration treatment of acetone.

Prior Art and Technical Problems of the Invention Zeolites have excellent water absorption performance and are highly selective in adsorbing large amounts of water due to their molecular action, so they are useful for the purpose of removing water contained in various organic substances. Widely used. For example, although water contained in acetone is relatively difficult to remove, it is known that when zeolite is used as a dehydrating agent, the water content in acetone can be reduced to 100 ppm or less.

Although zeolite has relatively few side reactions and side effects during dehydration treatment, it still has a contact effect with certain types of chemicals, and in the case of acetone dehydration mentioned above,
Acetone produces trimerized diacetone alcohol as a by-product,
This poses a problem of reducing the purity of acetone after dehydration.

JP-A No. 48-52714 discloses that by pre-treating zeolite with an acid having a molecular diameter larger than the pore diameter of the zeolite, for example, an organic acid such as citric acid or an inorganic acid, diacetone alcohol can be added as a by-product. It has been described that it suppresses the growth of

However, the above-mentioned acid treatment tends to lower the crystallinity of the zeolite and lower its water adsorption performance, and also significantly suppresses the amount of diacetone alcohol by-product compared to untreated zeolite. However, the objective of suppressing the amount of by-products as much as possible is still not fully satisfied.

Purpose of the Invention Therefore, the purpose of the present invention is to provide a method for obtaining a zeolite adsorbent for dehydration that has excellent water adsorption performance and effectively suppresses side reactions and side effects during one dehydration treatment (adsorption treatment). is to provide.

Another object of the present invention is to provide a method for producing an olide adsorbent that can suppress basicity, which causes side reactions and side effects, to a relatively low level without substantially destroying zeolite crystals. It is in.

Still another object of the present invention is to provide a zeolite for dehydration that can effectively adsorb and remove water in acetone while suppressing the by-product of diacetone alcohol to a significantly low level.

Structure of the Invention According to the present invention, a method for producing a zeolite adsorbent for dehydration is characterized in that A-type zeolite is treated in an aqueous medium containing an ammonium salt of a mineral acid before or after granulation. is provided.

Features and Effects of the Invention The reason why zeolite causes side reactions such as acetone doubling during water adsorption treatment is thought to be because zeolite exhibits catalytic activity as a solid base. Now, considering the state of alkali ions when zeolite is dispersed in water, (a) alkali ions dissociated from zeolite particles and eluted into water, (b) alkali ions existing on the surface of zeolite particles, and ( c) Three types of alkali ions are considered to be incorporated within the zeolite crystal structure.

According to the research conducted by the present inventors, it is the free alkali ions (,) above and the surface alkali ions (b) that are involved in the internal reaction of alkali ions in zeolite.
It has been found that when these alkali ions can be removed, the tendency for side reactions can be effectively suppressed. In addition, the above (
It has been found that when the alkali ions in the crystal structure of c) are neutralized, this results in a decrease in crystallinity and a decrease in adsorption performance.

The degree of neutralization is completely unrelated to whether the molecular diameter of the acid is larger than the pore diameter of the zeolite, and even if an acid with a large molecular diameter such as sulfuric acid is used, Neutralization of bound alkali ions occurs. In particular, with a strong acid such as sulfuric acid, when attempting to neutralize the alkali ions of (,) and (b), the neutralization of the structural ion of (c) will necessarily occur. This is because the neutralization of zeolite is carried out in a microscopically extremely heterogeneous state.

According to the present invention, the neutralization of zeolite using ammonium salts of mineral acids allows the above-mentioned (,) and (b) Although the alkali ions are reliably neutralized and removed, the alkali ions in (c) above are substantially prevented from being neutralized, and as a result, excellent adsorption performance is maintained, while side reactions caused by the solid base are prevented. and side effects are effectively suppressed.

Preferred Embodiments of the Invention The type A zeolite targeted by the present invention may be any zeolite known per se.

A type zeolite ideally has a chemical structure represented by the following formula: % where M represents a cation, X represents the valence of the cation, and y is a number of 27 or less. . As a cation, sodium type (
4A), potassium type (3A), calcium type (5A),
Examples include hydrogen ion type and mixed types. The particle size of synthetic zeolite powder is generally 0.0
A range of 1 to 100 microns, particularly 0.1 to 50 microns, can be used.

According to the invention, this large zeolite is treated in a carbonated aqueous medium prior to or after granulation. In terms of the remarkableness of the treatment effect and the fact that no special considerations are required, it is advantageous to apply the treatment according to the present invention to the already formed granular zeolite adsorbent, while in terms of manufacturing costs it is advantageous to carry out the treatment before granulation. is desirable.

The granular zeolite adsorbent to be subjected to the treatment of the present invention includes:
Any granulated material known per se can be used as long as it contains type A zeolite.

Zeolite granulation is generally done using the A-type zeolite mentioned above.
This is carried out by mixing a clay binder or further a water-soluble polymer binder, and subjecting this mixture to a granulation means known per se. As the clay binder, one or more of kaolin group clay minerals such as kaolin; palygorskite group clay minerals such as atta/lugite; smectite type clay minerals such as acid clay, montmorillonite, and bentonite, or allophanes, etc. It is possible to use them in combination. The particle size of the clayey binder can be used in the range of 0.1 to 10 microns, especially 0.5 to 5 microns. Clay binder - is A
5 to 30% by weight, especially 10 to 20% by weight of type zeolite
It can be used in amounts of % by weight.

In producing granular zeolite, a synthetic zeolite-clay binder mixture having the composition described above is granulated into cores using (if necessary) an aqueous solution of a water-soluble polymer binder as a granulation medium. Mixing of synthetic zeolite and clay binder can be done using regenblender or unical blender.
This can be carried out by dry blending using a known mixer such as a Henschel mixer. This mixture can be granulated using any granulation method known per se using the aqueous solution as a granulation medium, such as transfer granulation, extrusion granulation, vJt atomization granulation, tablet granulation, fluidization granulation, etc. It can be done with From the point of view of the mechanical strength of the granular zeolite, the transfer granulation method is particularly preferable, and the seed particles of the synthetic zeolite clay binder mixture are prepared,
Granulation is carried out by depositing the powder of the mixture onto the seed particles while moistening them with a granulation medium to cause grain growth.

The water-soluble polymeric binder can be used in an amount of 0.01 to 5% by weight, especially 0.05% to 2% by weight, based on the total amount of synthetic zeolite-clay binder as solid content, while the aqueous solution as granulation medium is preferably used in an amount of 20 to 70% by weight, particularly 30 to 60% by weight, based on the total amount, although it differs depending on the granulation method.

Water-soluble polymer binders include starch, cyanethylated starch, carboxymethyl starch, CalR oxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hollyvinyl alcohol, vinyl ether maleic acid copolymer, sodium alginate, sodium lignin sulfonate, arabic Rubber, tragacanth rubber, etc. can be used.

The obtained granules are air-dried and then calcined at a temperature of 300 to 600°C for 0.5 to 10 hours to obtain a granular zeolite adsorbent for dehydration treatment.

The shape of granular zeolite may be any shape such as sphere, tablet, or pellet, and its dimensions are generally 0.
It is desirable that the amount is in the range of 5 to 5 gourds, especially 1 to 3 gourds.

In the treatment of the present invention, ammonium salts of mineral acids such as ammonium sulfate, ammonium nitrate, and ammonium chloride can be used. Prior to treatment of the granular zeolite adsorbent with an aqueous medium containing a mineral acid ammonium salt, it is desirable to contact the granular zeolite adsorbent with water in advance.

This pretreatment has the desirable effect of retarding the adsorption of ammonia into the zeolite.

The treatment of zeolites with mineral acid ammonium salts is carried out by uniformly contacting the zeolite adsorbent with an aqueous medium containing said ammonium salts. Stirring, liquid circulation, or the like may be used to uniformly bring the two into contact.

Although room temperature is sufficient for the treatment temperature, slight cooling or heating may be performed if necessary.

There is a certain preferable range for the degree of hardness of the ammonium salt in the treatment liquid, and it is usually convenient to use a range of 1 to 20% by weight, particularly 5 to 10% by weight.

That is, it was found that the rate of side reactions during adsorption treatment increases both when it is higher and lower than this range.

There are no particular restrictions on the concentration of zeolite in the aqueous slurry, but from the viewpoint of ease of treatment and economy, it is desirable that the zeolite solid concentration be 10 to 40% by weight (anhydrous basis). The end point of the treatment can be known when the - of the zeolite slurry becomes about 10 or less, and therefore it is sufficient to carry out the treatment at a level of about 0.1 to 5.

This process can be performed multiple times, 92 or more times, if desired.

The zeolite after treatment is washed with water to remove contaminant salts, etc., and filtered, and then filtered to remove water in the zeolite.
For example, drying is performed at a temperature of 150 to 350° C. for 1 to 5 hours.

Alternatively, by reversing the order, the above-mentioned treatment is performed on the A-type zeolite before granulation, especially the water-washed zeolite slurry or cake obtained in the zeolite synthesis step, and the zeolite after treatment is subjected to the above-mentioned granulation means and calcination means. It can also be attached to

Furthermore, granular zeolite is produced from A-type zeolite treated with an aqueous medium containing an ammonium salt, and this granular zeolite is treated again in an aqueous medium containing an ammonium salt. Treatment may also be carried out in a containing aqueous medium.

The granular zeolite adsorbent according to the invention is advantageously used for the dehydration of acetone. This dehydration treatment is carried out by filling an adsorption tower with the granular zeolite adsorbent and passing acetone containing water through this fixed bed. The temperature during the adsorption treatment is preferably 40° C. or lower, preferably 30° C. or lower, and the space velocity is preferably within the range of 1 to 10 hr.

Of course, the granular zeolite adsorbent according to the present invention is not limited to the above-mentioned applications, but can also be used for organic chemicals in petroleum refining and various chemical industries, such as butanol, carbon tetrachloride, dichloroethylene, dichloropropylene, heptaoxide refrigerants, Phenol, acrylonitrile, pyridine, ethanol, 2
- Widely used for drying and dehydration of ethylhexanol, 2-ethylhexyl chloride, butyl chloride, amyl acetate, dimethylformamide, ethyl ether, isopropyl ether, isoglono-9ol, tetrahydrofuran, methylene chloride, methyl chloride, glopylene oxide, and other solvents. Can be used.

Example The excellent effects of the present invention will be explained with the following examples.

Example 1 Commercially available Na-A zeolite was heated to 15% using a constant temperature dryer.
After drying at 0℃ for 3 hours, add 0.3 U to 5% NH4C aqueous solution 1
dipped in water and left to stand for lhr. After measuring - of the liquid, it was washed with water and dried in a constant temperature dryer for 3 hours at 150°C.

The X-ray diffraction intensity is measured using the sample after drying. Similarly to the above, the Na-A type zeolite which was not treated with NH4O was dried at 150 DEG C. for 3 hours using a constant temperature dryer, and then the X-ray diffraction intensity was measured.

X-ray diffraction intensity is diffraction angle 2θ' = 24.0, 27.1
, 29.9 is defined as the sum of the diffraction heights of the three strong lines (Lo: nl).

Further, the degree of deterioration of the X-ray diffraction intensity is defined as follows.

Deterioration degree (%) = ((Σho - Σht), 4ho l
Table 1 shows the 100NH40 treatment and the measurement of the degree of deterioration.

The X-ray diffraction measurement device is a fissure X-ray generator from Rigaku Denki Co., Ltd.;
Company, CatA4036A1 Duometer; Company, C
The measurement was carried out by a conventional powder measurement method using AT42125D1.

The X-ray diffraction conditions are shown in Table-2.

For one measurement, a HORIBA M-7 type meter was used.

The NH4O-treated Na-A type zeolite powder is molded under the following conditions.

18% by weight of kaolin was added to 82% by weight of the dry powder and extrusion molded to a size of 1.5 mφ using a PeJ/eter E) -60 model manufactured by Fuji Paudal Co., Ltd. After that, after drying at 150℃ for 3 hours using a constant temperature dryer, Toshiba Electric Co., Ltd.
Firing was performed at 550° C. for 2 hours using a BH type Tecorundum electric furnace.

Examples 2 and 3.4 The Na-A type zeolite powder is molded by the method of Example 1, and then dried and calcined to obtain a sample for treatment with ammonium salt of mineral acid.

The processing method is Na-A zeolite molded product 0.3 kl?
(Based on products fired at 550°C for 2 hours) is immersed in an aqueous solution IJ of ammonium salts of mineral acids shown in Table 1, and left to stand for 1 hour. Thereafter, it was thoroughly washed with water and dried in a constant temperature dryer at 150° C. for 3 hours, and then the degree of deterioration was determined based on Example 1.

Table 1 shows various processing conditions and measurement results of the degree of deterioration.

Comparative Example 1 Based on the published patent publication No. 55-51033, the Na-A type zeolite molded product was subjected to soda removal treatment, and the degree of deterioration was determined based on Example 1.

The measurement results are shown in Table-1.

Comparative Example 2 Based on the published patent publication JP-A-48-52714, the Na-A type zeolite molded product was subjected to soda removal treatment, and the degree of deterioration was determined based on Example 1.

The measurement results are shown in Table-1.

Table 2 Table 1 It is clear that the degree of deterioration in X-ray diffraction is low when treated with ammonium salt of mineral acid.

Examples 5, 6, 7.8 Molded and fired products of NH4O treated powder in Example 1 Sample IP for measuring the degree of deterioration after molding and drying of various ammoniums in Examples 2 and 3.4 The water was replaced with 100 cc of iodine. Boil for 10 minutes, then cool to 1. Then - take measurements. The results are shown in A-3.

Revised Example 3 Seven Comparative Example 1
Measure the % suspension. The results are shown in Table-3.

Revised Example 4 7 Using the sample for measuring the degree of deterioration of Comparative Example 2, 1 was carried out in the same manner as in Example 5.
Measure the suspension. The results are shown in Table-3.

Example 1 Using the untreated zeolite molded and fired product in Example 1, the 1-chi suspension was measured in the same manner as in Example 5.

The results are shown in Table-3.

Table 3 As shown in Examples 5, 6, 7, and 8 of Table 3, the effect of dealkalization (soda) on the ammonium salt treatment of Shogo Shun is remarkable.

Example 9 A dynamic dehydration experiment of acetone was conducted using the NH4C-treated Na-A type zeolite powder molded calcined product in Example 1, and the diacetone alcohol (DA) produced in acetone after dehydration was
A) Concentration and moisture were measured.

The experimental method was to put 20 cc of a sample obtained by drying the molded and fired product at 200°C for 2 hours using a constant temperature dryer into an adsorption tower of 1.6 mφ x 40 necks, and add 80 cc of acetone with a moisture content of 2713 ppm.
The liquid was passed at a space velocity of ee/hr and a space velocity of 4 hr-'. After passing through the liquid, 80 cc of water was sampled every hour to analyze the concentration of water in acetone and diacetone alcohol (D0).To measure the water in acetone, a Mitsubishi Chemical Corporation Digital Trace Moisture Needle was used. CA-02 model was used. Yanagimoto Seisakusho Gas Chromatography Model 080 was used for the DAA production concentration analysis. The results are shown in Table 4.
Shown below.

Example 10 Using the sample for measuring the degree of deterioration in Example 2, an acetone dehydration experiment was conducted according to the experimental method of Example 9 above. The results are shown in Table 4.

Example 11 Using the sample for measuring the degree of deterioration in Example 3, an acetone dehydration experiment was conducted according to the experimental method of Example 9. The results are shown in Table 4.

Example 12 Using the sample for measuring the degree of deterioration in Example 4, an acetone dehydration experiment was conducted according to the experimental method of Example 9. The results are shown in Table 4.

Comparative Example 6 Using the sample for measuring the degree of deterioration of Comparative Example 1, an acetone dehydration experiment was conducted according to the experimental method of Example 9 above. Display the results -
4.

Comparative Example 7 Using the sample for measuring the degree of deterioration of Comparative Example 2, an acetone dehydration experiment was conducted according to the experimental method of Example 9 above. Display the results -
4.

Comparative Example 8 An acetone dehydration experiment was conducted according to the experimental method of Example 9 using commercially available 3A type zeolite 1.5 nwφ extrusion molding. The results are shown in Table 4.

Examples 9, 10, 11, 12 in Table 4 When type A zeolite treated with ammonium salt of sucrose acid was used for acetone dehydration, the dehydration ability did not decrease and the D
The effect of inhibiting AA production is remarkable.

Claims (2)

[Claims] (1) A method for producing a zeolite adsorbent for dehydration, which comprises treating type A zeolite in an aqueous medium containing an ammonium salt of a mineral acid before or after granulation. (2) The manufacturing method according to claim 1, wherein the zeolite is brought into contact with water in advance prior to the treatment.