JP2000154018A - Production of intermediate of crystalline microporous body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing the intermediate of a crystalline microporous body in a high yield. SOLUTION: This producing method includes a mixing process to mix at least one kind of crystallization controlling agent selected from ammonium ions (R4N+, wherein R is one species selected from hydrogen, <=10C alkyl groups or aryl groups), phosphonium ions (R4P+, wherein R is at least one species selected from hydrogen, <=10C alkyl groups or aryl groups) and amines, with an alkaline inorg. material mixture liquid containing kanemite fine particles, an ion-exchange process which proceeds with the mixing process simultaneously, and a stirring process to stir the reaction liquid obtd. in the mixing process at <=60 deg.C in a liquid state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorbent, a catalyst and a material for separation, that is, a CFC-based refrigerant, sulfur fluoride gas which is an insulating medium for high-voltage power equipment, air for a vehicle air brake, and the like. It is mainly used in the petrochemical industry, etc. as a desiccant, an adsorbent for nitrogen compounds in wastewater and an adsorbent for radioactive substances in radioactive wastewater, and as a catalyst for supporting various metals and supporting various uses. The present invention relates to a method for producing an intermediate of a crystalline microporous body.

[0002]

2. Description of the Related Art A large number of crystalline microporous materials exist as natural products such as mordenite and ferrierite, and zeolite-A, zeolite-X and ZSM-5 also exist as artificial crystalline microporous materials. (Special Publication 46-
10064) and ZSM-11 (Japanese Patent Publication No. Sho 5).
Various types are known. When producing an artificial crystalline microporous body as described above, after performing a mixing step of forming an alkaline mixed solution containing a silicon dioxide component, an aluminum oxide component, and an organic ammonium salt, And a crystallization step of crystallizing the crystalline microporous body in the inorganic material mixture by high-pressure heating, that is, a so-called hydrothermal synthesis method.

However, in the above-mentioned hydrothermal synthesis method, a high-pressure heating vessel is expensive, and the inorganic material mixture contains an alkali metal oxide or alkaline earth metal oxide component as an oxide or hydroxide. Therefore, in order to prevent corrosion by alkali, the high-pressure heating vessel must be made of stainless steel or treated with a fluorine resin coating or the like. Also,
In the crystallization step, it was necessary to heat the mixture at a high temperature condition of usually 70 ° C. to 200 ° C. in some cases or more, and in some cases for a long time of 10 days or more, which required severe reaction conditions. there were. In addition, the crystalline microporous body obtained by the hydrothermal synthesis method is in the form of fine particles, and although it is necessary to mold it in some cases, generally, the fine crystalline microporous body itself has a cohesive force. Therefore, sintering at extremely high temperatures or molding with a binder interposed must be performed, so that sintering at high temperatures melts the crystal surface layer and blocks the porous structure. The ratio of the crystalline microporous material in the molded product is reduced, and the ratio of the porous structure per unit weight of the molded product is reduced, and the adsorption activity, catalytic activity, and the like derived from the porous structure are reduced. Properties tended to be low.

[0004] In order to solve the above-mentioned problem, a crystallization regulator and an alkaline inorganic material mixed solution containing kanemite fine particles are mixed, and fine crystalline microparticles precipitated in the inorganic material mixed solution are mixed. There has been proposed a method for producing a crystalline microporous body in which a porous intermediate is separated from an inorganic material mixed liquid, and the solid component subjected to solid-liquid separation is heated and crystallized (Japanese Patent Laid-Open No. 8-319112). . The crystalline microporous material thus obtained is synthesized with energy saving, and the fine particles obtained as an intermediate have caking properties, which are effective physical properties in obtaining a molded product of the crystalline microporous material. have. The formation of the intermediate is considered to be due to a reaction mechanism in which kanemite forms a layered structure, that is, a layered silica structure, aggregates around the crystallization modifier while maintaining the layered structure, and forms the intermediate. Can be

Here, a mixture of a crystallization regulator and an alkaline inorganic material mixture containing kanemite fine particles has been stirred under a high temperature condition of about 70 to 80 ° C.
This is because stirring at such a temperature was considered to be optimal for activating the molecular motion of the crystallization modifier and increasing the amount of the crystallization modifier introduced into the layered silica structure. .

[0006]

However, the above intermediate has an insufficient yield of a layered silica structure. This is considered to be due to the dissolution of the layered silica structure of the intermediate.

Accordingly, an object of the present invention is to provide a method for producing a crystalline microporous intermediate in high yield, that is, to provide a crystalline microporous intermediate which prevents dissolution of a layered silica structure. It is to provide a manufacturing method.

[0008]

Means for Solving the Problems The present inventors have proposed the above-mentioned intermediate method.
When forming the body, the alkaline inorganic material mixed solution is stirred.
After a thorough study on the assumption that stirring temperature is involved,
At that time, adjust to liquid condition of 60 ° C or less.
High yield, high caking properties, and excellent moldability
Experimentally find that the body can be obtained, and based on this finding
Thus, the present invention has been completed. To achieve this purpose
Characteristic configuration of the method for producing the intermediate of bright crystalline microporous material
Is an ammonium ion (R_FourN⁺: R is hydrogen, carbon number 1
0 or less selected from an alkyl group or an aryl group.
At least one), phosphonium ion (R _FourP⁺: R is water
Element or an alkyl or aryl group having 10 or less carbon atoms
At least one selected from the group consisting of
At least one crystallization modifier and kanemite
Mixing with an alkaline inorganic material mixed solution,
And the reaction solution obtained in the mixing step
It has a step of stirring under the conditions. Crystallization
The modifier is a tetra-n-butylammonium ion ((n-
C_FourH₉)_FourN ⁺), Tetra n-propylammonium ion
((N-C_ThreeH₇)_FourN⁺), Tetraethylammonium
ON ((C_TwoH_Five)_FourN⁺), Tetramethylammonium ion
((CH_Three)_FourN⁺), N-propyltrimethylammonium
Mion ((n-C_ThreeH₇) (CH_Three) _ThreeN⁺), Benzyl trim
Thilammonium ion ((C₇H₇) (CH_Three)_ThreeN⁺), Tet
Ra-n-butylphosphonium ion ((n-C_FourH₉)
_FourP⁺), Benzyltriphenylphosphonium ion ((C
₇H₇) (C₆H_Five)_ThreeP⁺), 1,4-dimethyl-1,4-di
Azobicyclo (2,2,2) octane, pyrrolidine, n
-Propylamine (nC_ThreeH₇NH_Two), Methylquinuc
At least one cationic bond selected from lysine
It may be a crystallization regulator.

[Action] When kanemite and at least one crystallization modifier selected from ammonium ions, phosphonium ions and amines coexist under alkaline conditions, an inorganic material assembles around the crystallization modifier. . At this time, an intermediate of a crystalline microporous body, which is a fine particle of the composite, is arranged at a position where the inorganic materials are easily bonded to each other. The intermediate is isolated as a solid component by a solid-liquid separation step, and the isolated intermediate undergoes a phase change by heat treatment to be crystallized, whereby a porous crystal is obtained.

Here, the stirring of the mixed solution of the crystallization controlling agent and the mixed liquid of the alkaline inorganic material containing kanemite activates the molecular movement of the crystallization controlling agent to reduce the rate of introduction into the layered silica structure. Was thought to increase,
It has been considered that it is preferable to carry out the reaction under a high temperature condition of about 70 to 80 ° C. However, it has been experimentally proved that mixing under such a high temperature condition tends to dissolve the layered silica structure. It has been experimentally proved that when the mixture is stirred at a low temperature of 60 ° C. or lower, not only the production of the intermediate is possible, but also the production is possible in a short time and in an extremely high yield. Was. Moreover, it has been experimentally proved that the yield of the intermediate is drastically increased when the alkaline inorganic material mixed liquid is mixed under liquid conditions of about room temperature or lower, that is, 30 ° C. or lower.

The crystallization modifier includes an ammonium ion (R ₄ N ⁺ : R is at least one selected from hydrogen, an alkyl group or an aryl group having 10 or less carbon atoms), and a phosphonium ion (R ₄ P ⁺ : R is hydrogen, at least one selected from an alkyl group or an aryl group having 10 or less carbon atoms), as long as at least one of amines, selected from, in particular, tetra-n- butylammonium ion ((n-C ₄ H _{9) 4} n ^+), tetra-n- propylammonium ion _{((n-C 3 H 7} ) 4 n +), tetraethylammonium ion _{((C 2 H 5) 4} n +), tetramethylammonium ion ((CH ₃ ) ₄ N ⁺ ), n-propyltrimethylammonium ion ((nC ₃ H ₇ ) (CH ₃ ) ₃
N ⁺ ), benzyltrimethylammonium ion ((C ₇ H
_{7) (CH 3) 3 N} +), tetra-n- butyl phosphonium ion _{((n-C 4 H 9} ) 4 P +), benzyl triphenyl phosphonium ion _{((C 7 H 7) (} C 6 H 5) 3 P ⁺ ), 1,4-dimethyl-1,4-diazobicyclo (2,2,2) octane, pyrrolidine, n-propylamine (nC ₃ H ₇ NH)
₂ ), methylquinuclidine, and at least one selected from methylquinuclidine are preferable, and it is considered that various ammonium salts, phosphonium salts, and amines can be used. When a tetrapropylammonium salt is used, the final product is a crystalline microporous material having an MFI structure, and when a tetrabutylammonium salt is used,
Since a crystalline microporous body having an MEL structure is obtained, an intermediate of a crystalline microporous body having various pore sizes can be obtained by selecting the organic ammonium salt according to the structure to be synthesized.

The layered silica structure of the intermediate is SiO ₄
This is a sheet layer formed by two-dimensionally connecting tetrahedrons, and since the bonding point of the SiO ₄ tetrahedron is bendable, the sheet layer as a whole can be curved or bent. Therefore, the benzyltrimethylammonium ion
If a bulky crystallization controlling agent such as ((C ₇ H ₇ ) (CH ₃ ) ₃ N ⁺ ) is used, the inorganic material gathers around the bulky crystallization controlling agent, and a part between each sheet layer is formed. A sheet layer having a honeycomb-shaped layered silica structure that is curved in a curved manner is formed. And since the hydroxyl group from a silicon atom, ie, silanol (Si-OH), exists in the sheet layer of a layered silica structure,
The dehydration condensation between silanols (Si-OH) having a layered silica structure is promoted at the portions where the sheet layers are partially bent, forming siloxane bonds (Si-O-Si), and as a result, honeycomb-like crystallinity It is possible to obtain a microporous intermediate.

As a result, a crystalline microporous intermediate can be produced with a high yield.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.
In addition, as a raw material set, the one having the following composition was used (all the percentages shown are% by weight). ○ No. 3 water glass: Analytical value SiO ₂ : 29.17%, Na
₂ O: 9.82% (manufactured by Nippon Chemical Industry Co., Ltd.) ○ Tetrapropylammonium bromide ((n-C ₃ H ₇ ) ₄ NB
r): (Tokyo Chemical Industry Co., Ltd.)

A No. 3 water glass was prepared in a 500 mL beaker, and sodium hydroxide was dissolved in the water glass. Then, the water glass was transferred to an evaporating dish made of alumina and placed in a thermostat at 150 ° C. to evaporate the water content. The product from which the water was evaporated was put into an electric furnace together with the evaporating dish and calcined at 700 ° C. for about 5 hours, and allowed to cool to room temperature to obtain a reaction product. This product is sodium disilicate. When the raw material sodium disilicate powder is put into deionized water, kanemite fine particles are generated,
This partially dissolves in the mixing step with the crystallization modifier, and silicate ions and sodium ions are eluted, so that kanemite fine particles are dispersed in the aqueous sodium silicate solution.
By filtering this, kanemite fine particles remain, but sodium silicate flows out together with the filtrate. When the remaining aqueous solution of sodium silicate-kanemite is dried, sodium silicate precipitates as amorphous, and becomes a mixture of kanemite and amorphous. Incidentally, if the synthesis is carried out under the condition that the kanemite is little dissolved, a high quality intermediate having a small amount of the amorphous component can be obtained. The intermediate is a product in which crystallization control agent is combined with kanemite and amorphous by a chemical reaction. When this intermediate is exposed to high temperature conditions, a crystalline microporous body is obtained.

FIG. 1 shows the relationship between the stirring temperature of the mixed solution of the crystallization regulator and the alkaline inorganic material mixed solution containing kanemite, and the yield of the intermediate. here,
Tetrapropylammonium bromide (TPABr) was used as a crystallization regulator, the pH of the reaction solution of the crystallization regulator and kanemite was adjusted to 11.8, and stirring and mixing were performed for 3 hours. From FIG. 1, it is possible to increase the yield of the intermediate by stirring a mixture of a crystallization modifier and an alkaline inorganic material mixture containing kanemite under a liquid condition of 60 ° C. or less. Understand what you can do.

[Embodiment 1] 4.0 kg of sodium disilicate powder was dispersed in 90 L of deionized water, and after the generated kanemite was precipitated, the supernatant was removed to make 20 L.
Deionized water was added again to make 40 L, and tetrapropylammonium bromide (TPAB) was added as a crystallization regulator.
r) 1200 g were added. This was stirred at room temperature of 25 ° C. for 3 hours to perform ion exchange. Thereafter, the pH was reduced to 10.5 by adding 2 mol / L hydrochloric acid. The resulting slurry was filtered and dehydrated while being washed with deionized water, and then spray dried to obtain 3.6 kg of a white powder as an intermediate of the crystalline microporous body. The yield based on the sodium disilicate powder was 90%. Filtration and dehydration uses a rotary filter to reduce the thickness of the solid component on the filter to 2 mm.
By performing while maintaining the following, a large amount of processing can be performed at once. Further, the spray drying is performed by using a spray dryer that performs spray drying by circulating gas in a drying chamber atmosphere, and controlling the temperature of the fine particles at the entrance to the drying chamber by 100%.
By drying at a temperature of not less than 150 ° C. and not less than 150 ° C., denaturation of kanemite in the intermediate can be prevented. When the obtained powder was examined by powder X-ray diffraction spectrum measurement, a strong peak due to the kanemite crystal structure remained, and a diffraction pattern with a small amount of amorphous component was obtained. Examination of the TPA content of this powder by thermogravimetry showed that the weight ratio was about 10%, and that a sufficient amount of TPA for crystallization of the zeolite was introduced between the kanemite layers. Further, this was heated at 150 ° C. for 24 hours in a closed container made of Teflon, and the product was examined by powder X-ray diffraction spectrum measurement. As a result, it was found that the product was a crystalline microporous material composed of silicalite. Note that, as in the above-described embodiment, an alkaline inorganic material mixed solution containing a crystallization modifier and kanemite was mixed with a pH of 1
The reason for adjusting the ratio to 0.5 is to prevent the formation of interlayer crosslinking in the layered silica structure of the intermediate, and to improve the moldability when the intermediate is preformed. That is, by forming the alkaline inorganic material mixed solution in a range of pH 9.0 or more and 12.5 or less, the intermediate having good moldability can be obtained in performing preliminary molding.

[Embodiment 2] In the same process as in Embodiment 1, ion exchange was performed by heating to 40 ° C. 3.5 Kg of a white powder was obtained, and the yield based on the sodium disilicate powder was 88%. When the obtained powder was examined by powder X-ray diffraction spectrum measurement, a peak derived from the kanemite crystal structure was strongly exhibited, and a diffraction pattern with a small amount of amorphous component was obtained. Examination of the TPA content of this powder by thermogravimetry showed that the weight ratio was about 10%, and that a sufficient amount of TPA for crystallization of the zeolite was introduced between the kanemite layers. Further, this was heated at 150 ° C. for 24 hours in a closed container made of Teflon, and the product was examined by powder X-ray diffraction spectrum measurement. As a result, it was found that the product was a crystalline microporous material composed of silicalite.

[Embodiment 3] In the same process as in Embodiment 1, ion exchange was carried out by heating to 60 ° C. 3.2 kg of white powder was obtained, and the yield based on the sodium disilicate powder was 80%. When the obtained powder was examined by powder X-ray diffraction spectrum measurement, a peak due to the kanemite crystal structure appeared considerably, and a diffraction pattern with less amorphous components was obtained. Using this powder, a honeycomb-shaped molded product was formed by extrusion molding. Although the formability was good and the folds were slightly formed, a honeycomb body having a sufficient shape was obtained. Examination of the TPA content of this powder by thermogravimetry showed that the weight ratio was about 11%, and that a sufficient amount of TPA for crystallization of the zeolite was introduced between the kanemite layers. Further, this was heated at 150 ° C. for 24 hours in a closed container made of Teflon, and the product was examined by powder X-ray diffraction spectrum measurement. As a result, it was found that the product was a crystalline microporous material composed of silicalite.

[Embodiment 4] In the same process as in Embodiment 1, ion exchange was performed by cooling to 0 ° C. White powder3.
6 kg was obtained, and the yield based on the sodium disilicate powder was 90%. When the obtained powder was examined by powder X-ray diffraction spectrum measurement, a peak due to the kanemite crystal structure appeared considerably, and a diffraction pattern with less amorphous components was obtained. Examination of the TPA content of the powder by thermogravimetry revealed that the weight ratio was about 9%, and that a sufficient amount of TPA for crystallization of the zeolite was introduced between the kanemite layers. Further, this was heated at 150 ° C. for 24 hours in a closed container made of Teflon, and the product was examined by powder X-ray diffraction spectrum measurement. As a result, it was found that the product was a crystalline microporous material composed of silicalite-I.

[Comparative Example 1] In the same process as in Embodiment 1,
The mixture was heated to 70 ° C. to perform ion exchange. 2.6 white powder
Kg was obtained, and the yield based on the sodium disilicate powder was 65%. When the obtained powder was examined by powder X-ray diffraction spectrum measurement, a diffraction pattern having few peaks attributed to the kanemite crystal structure and having many amorphous components was obtained. It is considered that this amorphous component was obtained by dissolving the dissolved kanemite silica component during drying. When the TPA content of this powder was examined by thermogravimetry, the weight ratio was about 12%, and there was no significant difference from Embodiments 1 to 4.

[Another Embodiment] At least one crystallization modifier selected from ammonium ions, phosphonium ions, and amines and a silicon dioxide component such as kanemite fine particles are mixed under a liquid condition at 60 ° C. or lower and in the presence of aluminum ions. It is also possible to mix below. That is, when exposing the intermediate of the crystalline microporous body to aluminum chloride vapor or forming a composite of a crystallization modifier and a silicon dioxide component, an aluminum element is introduced into the layered structure by introducing aluminum ions. You can also. A molded product from such an intermediate can be used as a catalyst for the production of ethylbenzene or para-xylene.

Further, in the above-described embodiment, sodium disilicate powder was obtained by firing water glass, but commercially available layered sodium silicate powder (such as SKS-6 of Clariant Japan) as a silicon dioxide component. Can also be used. In such a case, an intermediate of a crystalline microporous body can be manufactured at low cost because the process does not go through a firing step using an expensive electric furnace.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the stirring temperature of a mixed solution of the crystallization regulator and an alkaline inorganic material mixed solution containing kanemite, and the yield of the intermediate.

Continued on the front page (72) Inventor Shinichi Shimizu 5-6-1 Koyodai, Ryugasaki-shi, Ibaraki Pref. UA04 UA06

Claims (2)

[Claims] 1. An ammonium ion (R ₄ N ⁺ : R is at least one selected from hydrogen, an alkyl group or an aryl group having 10 or less carbon atoms), a phosphonium ion (R
₄ P ⁺ : R is at least one selected from hydrogen, an alkyl group or an aryl group having 10 or less carbon atoms), at least one crystallization modifier selected from amines, and an alkaline inorganic material mixed solution containing kanemite. And an ion exchange process, and a step of stirring the reaction solution obtained in the mixing process under a liquid condition of 60 ° C. or lower. 2. The method according to claim 1, wherein the crystallization controlling agent is tetra-n-butylammonium ion ((nC ₄ H ₉ ) ₄ N ⁺ ), tetra-n-butyl ammonium ion.
Propylammonium ion _{((n-C 3 H 7} ) 4 N +), tetraethylammonium ion _{((C 2 H 5) 4} N +), tetramethylammonium ion ^{_{((CH 3) 4 N +}} ), n- propyl trimethyl ammonium ion _{((n-C 3 H 7} ) (CH
₃ ) ₃ N ⁺ ), benzyltrimethylammonium ion ((C
_{7 H 7) (CH 3)} 3 N +), tetra-n- butyl phosphonium ion _{((n-C 4 H 9} ) 4 P +), benzyl triphenyl phosphonium ion _{((C 7 H 7) (} C 6 H 5 ) ₃ P ⁺ ), 1,4-dimethyl-1,4-diazobicyclo (2,2,2) octane, pyrrolidine, n-propylamine (nC ₃ H ₇ NH)
₂ ) The method for producing an intermediate of a crystalline microporous material according to claim 1, which is at least one cationic crystallization modifier selected from methylquinuclidine.