JPS6183620A - Production of crystalline zeolite - Google Patents

Abstract

PURPOSE:To obtain a crystalline zeolite useful as a catalyst for the catalytic conversion of hydrocarbons, by using an oxide mixture having oxide molar ratios falling within specific ranges as a raw material, and crystallizing the mixture until a crystalline zeolite is produced. CONSTITUTION:The objective product can be produced by using a homogeneous phase compound of granular amorphous aluminosilicate of formula I or formula II (M is metallic cation; n is atomic valence of the cation; R is quaternary ammonium ion) in terms of the molar ratios of oxides (preferably containing further a quaternary ammonium salt) as a raw material, and crystallizing the material until crystalline zeolite is produced. The silica source and the alumina source of the above raw material are produced by the simultaneous and continuous reaction of an aqueous solution of an alkali metal silicate with an aluminum-containing aqueous solution. The nitrogen content of the solution left after the separation of solid component from the crystallized reaction mixture is preferably <=500ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a crystalline zeolite having a high S I O2/AZ20 s molar ratio.

The crystalline zeolite in the present invention includes ZSM-5,
They are collectively referred to as the so-called pentasil type, such as ZSM-'8, ZSM-11, and ZSM-12 type zeolites and silicalites. These crystalline zeolites are
Catalysts, such as the catalytic conversion of hydrocarbons such as crackers, kings, isomerizations, etc., or adsorbents, in some cases can be used as molecular sieves.

[Conventional technology]

The following method has been proposed for producing crystalline zeolite by making quaternary ammonium ions (R+) present in a raw material mixture consisting of silica, alumina, metal cations, and water.

(1) The method disclosed in Japanese Patent Publication No. 46-10064 involves reacting a raw material mixture that essentially contains quaternary ammonium ions and tetraethylammonium ions in a R20/SIO□ molar ratio of 0.017 or more. A method of manufacturing ZSM-5 type zeolite.

(2) The method disclosed in Japanese Patent Publication No. 53-23280 uses tetrabutylammonium ions as quaternary ammonium ions at an R20/SIO□ molar ratio of 0.0.
By reacting a raw material mixture that must contain two or more Z
A method for producing SM-11 type zeolite.

(3) The method disclosed in British Patent Publication 1,334.243 uses tetraethylammonium ions as quaternary ammonium ions in a total R20/SiO2 molar ratio of 0.
A method for producing ZSM-8 type zeolite by reacting a raw material mixture that essentially contains 04 or more.

(4) The method disclosed in Japanese Patent Publication No. 52-16079 uses tetraethylammonium ion 'i R2C4102 molar ratio of 0.0 as quaternary ammonium ion.
A method for producing ZSM-12 type zeolite by reacting a raw material mixture that essentially contains 0.028 or more.

(5) The method disclosed in JP-A-54-72795 uses tetrapropylammonium ion, tetraethylammonium ion, or tetrabutylammonium ion as a quaternary ammonium ion in R2.
A method for producing silicalite by reacting a raw material mixture that must contain a 0/sIO□ molar ratio of 0.017 or more.

(6) The method disclosed in JP-A-54-75499 uses tetraethylammonium ion'e R20/310□ molar ratio of 0.
A method for producing ZSM-12 type organosilicate by reacting a raw material mixture that essentially contains 014 or more.

In either method, there are a large number of quaternary ammonium ions used, and quaternary ammonium Since a large amount of ions remain, it is necessary to detoxify them. This not only increases the cost of raw materials, but also necessitates complicated operations for detoxification treatment.

In addition, ZSM-5 type or ZSM-5 type without using nitrogen-containing organic ions such as quaternary ammonium ions
Methods of building similar zeolites have been proposed. For example, there are (1) Japanese Patent Publication No. 56-49851, (2) Japanese Patent Application Publication No. 56-37215, and (3) Japanese Patent Application Publication No. 57-7819. These methods cannot produce zeolites with a high 51o2/At203 molar ratio, such as a 5io2At2o3 molar ratio of 100 or more. moreover,
When used as a catalyst, it is necessary to perform ion exchange.

Also, instead of quaternary ammonium ions,
A method for producing ZSM-5 using a grade amine has been proposed. For example, the following methods have been proposed, but in either case, the production cost is high because a larger amount of amine than the quaternary ammonium salt is used, and most of the amines are contained in the crystallization mother liquor. However, there are problems in that some residual substances remain and it is necessary to detoxify them.

The prior art described above relates to a method using water glass, colloidal silica, or powdered amorphous solid silica as a silica source.

[Problems that non-invention attempts to solve]

The object of the present invention is to solve the problem of 5
Crystalline zeolite with a high iO27At203 molar ratio,
The object of the present invention is to provide a method that can be easily and extremely economically produced on an industrial scale with high purity by using a small amount of quaternary ammonium ion.

By realizing the synthesis of crystalline zeolite using such a small amount of quaternary ammonium ions, it is possible to produce it at low cost, and since the content of harmful nitrogen-containing organic substances in wastewater is extremely low, Complicated processes such as wastewater treatment and recovery of nitrogen-containing organic matter can be omitted.

[Means for solving problems]

The present inventors used a granular amorphous aluminosilicate homogeneous phase compound obtained by simultaneously and continuously reacting an alkali metal silicate aqueous solution and an aluminum-containing aqueous solution as a silica and alumina source; When quaternary ammonium ions are contained in the granular amorphous aluminosilicate phase complex, crystalline zeolite with a high 8102/Al2O3 molar ratio can be obtained by using a small amount of quaternary ammonium ions. that light is readily available;
In addition, it has been found that almost no quaternary ammonium ions remain in the crystallization mother liquor, and the amount is at most 500 ppm or less.

The present invention has been made based on this knowledge. The details will be explained below.

[Effect]

The granular amorphous silicate homogeneous phase compound used in the present invention is obtained by simultaneously and continuously reacting an aqueous alkali metal silicate solution and an aqueous aluminum-containing solution. In this reaction, simultaneous and continuous reaction means:
This refers to an embodiment in which the alkali metal silicate aqueous solution and the aluminum-containing aqueous solution are supplied simultaneously and in such a manner that a constant ratio is maintained substantially all the time. The alkali metal silicate aqueous solution is an aqueous solution of sodium silicate, potassium silicate, lithium silicate, etc., or a mixture thereof. In addition, aluminum-containing water bath liquids include aluminum sulfate, aluminum nitrate, aluminum chloride,
It is an aqueous solution of sodium aluminate, potassium aluminate, etc. Further, in order to adjust the amount of acid or alkali, an alkali hydroxide or a mineral acid may be added as necessary. The concentrations of the alkali metal silicate aqueous solution and aluminum-containing aqueous solution are not particularly limited, and any concentration can be used.

The most preferred embodiment for preparing a granular amorphous aluminosilicate homogeneous phase compound using this method is a method in which both aqueous solutions are simultaneously and continuously fed into a reaction tank equipped with a stirrer with an overflow under stirring. It is. This method is effective because the produced homogeneous compound is approximately spherical or in the form of fine particle agglomerates, and most of the particle diameters are distributed in the range of 1 to 500 μm, with only a very small amount of fine particles of 1 μm or less. In the practice of this invention, it is preferred to use homogeneous compounds of 10 to 100 microns. The supply ratio of both aqueous solutions is 810□7At20 of the target crystalline zeolite.
3 molar ratio, and can be arbitrarily determined. At this time, the reaction solution suspends the granular homogeneous compound produced by the reaction and becomes a slurry. The range is more preferably adjusted to a range of -6 to 8. Further, the time that the slurry stays in the reaction tank is preferably 3 minutes or more. The residence time here means the time from when both aqueous solutions are simultaneously and continuously supplied to the reaction tank until the reaction slurry containing the homogeneous compound produced by the reaction is discharged from the reaction tank.

When the residence time is shorter than 3 minutes, the generation rate of fine particles increases. Moreover, as the proportion of fine particles of 1μ or less increases,
The resulting compound tends to be unfavorably loaded in the process of passing through and separating it. On the other hand, when the residence time is 3 minutes or more, most of the product becomes spherical and the presence of fine particles becomes extremely small. Furthermore, as the residence time becomes longer, the particle diameter increases, and at the same time, the bonds between the particles become stronger, and the hardness of the spherical particles increases.

The reaction temperature during the production of the homogeneous compound is not particularly limited, and it will become spherical at both low and high temperatures, but as the temperature increases, the particles will grow faster and the bonds between the particles will become stronger. , the hardness of spherical particles increases.

Therefore, it is necessary to adjust the residence time and reaction temperature.
Since the size and hardness of the spherical particles produced can be changed, the reactivity of the homogeneous compound itself can be adjusted depending on the purpose.

A further characteristic feature is that by reacting both aqueous solutions at a fixed ratio simultaneously and continuously, the composition of the spherical homogeneous compound that is first produced is microscopic regardless of the size of the spherical particles. Since all of the components are uniform, it is possible to completely prevent the coexistence of impurities caused by non-uniformity of the composition.

Since the homogeneous compound obtained by the method of the present invention is obtained in the form of spheres of appropriate size, solid-liquid separation and washing are extremely easy, which is also one of the features of the present invention. Therefore, solid-liquid separation can be carried out using an ordinary centrifugal separator or vacuum filtration machine, and since it has excellent dehydration properties and is obtained in the form of a wet cake with a low water content, this can be crystallized into crystalline zeolite. A wide range of water balance settings is possible when preparing reaction mixtures for It is advantageous to use the homogeneous compound after washing in the form of a wet cake, but it is of course possible to use it in dry form.

The homogeneous compound obtained by the method of the present invention has a significant feature of having cation exchange ability.

In particular, it exhibits a very high exchange rate and capacity for quaternary ammonium ions. Sara K.

Very high adsorption capacity for quaternary ammonium ions. Therefore, the homogeneous compound of the present invention selectively (and rapidly) retains quaternary ammonium ions. This fact is quite surprising; the more uniform the particle size of the homogeneous compound, the more The more homogeneous the quaternary ammonium ion is, the greater the ability to retain the quaternary ammonium ion is l/1°.The method for retaining quaternary ammonium ions in a homogeneous compound is This can be easily done by methods such as immersion.

In addition, as a more useful method for retaining quaternary ammonium ions in a homogeneous compound, when producing a homogeneous compound, an aqueous solution of an alkali metal silicate as a raw material or
A method of adding quaternary ammonium ions to an aluminum-containing aqueous solution is mentioned. During solid-liquid separation and washing of the homogeneous compound prepared by this method, almost all of the quaternary ammonium ions are present in the solid phase of the homogeneous compound, and it is extremely unlikely that the quaternary ammonium ions will migrate into the liquid phase. It is. This fact is very surprising.

When crystallization is performed using a homogeneous compound containing quaternary ammonium ions produced by the method described above, only a small amount of quaternary ammonium ions migrate into the liquid phase, and most of the quaternary ammonium ions are transferred to the zeolite. It was found that it exists in the solid phase.

On the other hand, the alkali metal silicate aqueous solution and the aluminum-containing aqueous solution are mixed by a batch method in which one aqueous solution is added to the other aqueous solution, or a batch method in which both aqueous solutions are added simultaneously and the reaction slurry is not discharged. When this is done, the resulting compound has a wide particle size distribution and is microscopically non-uniform.

Such compounds have a very low ability to retain quaternary ammonium ions, and even if they can retain quaternary ammonium ions, there is a high possibility that a large amount will be discharged into the liquid phase in the subsequent crystallization step.

In addition, if this compound or the homogeneous compound of the present invention is not washed, residual inorganic salts such as sulfuric acid, salts, and nitrates will be adsorbed to the compound or homogeneous compound, resulting in the formation of quaternary ammonium ions. Preferably, this is prevented when the compound or homogeneous compound is retained.

Therefore, in order to achieve the purpose of effectively utilizing a small amount of quaternary ammonium ions of the present invention, K uses an alkali metal silicate aqueous solution and an aluminum-containing aqueous solution as the silica source and alumina source of the raw material mixture. The most preferred form is to use a granular amorphous aluminosilicate homogeneous phase compound obtained by simultaneous and continuous reaction. moreover,
A form in which quaternary ammonium ions are retained in a homogeneous compound is preferred.

The homogeneous compound thus obtained is mixed with water or an aqueous solution of an alkaline earth metal to prepare a raw material mixture. It is also possible to contain quaternary ammonium ions in water or an aqueous solution of prucari metal or alkaline earth metal. The raw material mixture prepared in this way is expressed in terms of molar ratio of oxides: 5102At203=10~MvryS102=0.001~l H2O/5102=5~50 RO/S10□=0.001~0.015 Preferably , 5102/At203=2ONω M2/r10/SlO□=0°001~1HO/510
2 = 7~50 RO/5iO2 = 0.005~0.015 (by that,
M is a metal cation, n is the valence of the metal cation, and R is a quaternary ammonium ion. ) has the following composition. Incidentally, s+o2/Az2o (to a urine-free level) means that the method of the present invention can be applied without substantial restrictions even when the amount of AA20° is extremely small.

Put this raw material mixture into an autoclave and heat it to 80℃~300℃.
Crystallization is carried out at a temperature of 1 hour to 10 days. After crystallization is completed, the generated crystals are separated from the crystallization mother liquor,
Wash with water and dry to obtain crystalline powder.

The crystallization mother liquor obtained with and ζ has a nitrogen content of 500 p
Pm or less.

In addition, H-type crystalline zeolite can be obtained by simply firing the obtained crystalline zeolite without ion exchange.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the amount of quaternary ammonium ions used is small and L 5to
Highly pure crystalline zeolite with a high 2/*t2o3 molar ratio can be easily obtained on an industrial scale.

The crystalline zeolite obtained by the present invention is calcined if necessary, and after performing ion exchange if necessary,
It can be used as a catalyst, adsorbent, and molecular entrainer.

〔Example〕

Preparation of homogeneous compounds〉 Overflow type reaction tank in stirring state (actual photo
2.4J), a sodium silicate aqueous solution having the composition of A to F shown in Table 1 and an aluminum sulfate aqueous solution with sulfuric acid added were simultaneously and continuously fed at a fixed rate of feed rate shown in Table 1. and reacted under stirring. The apparent residence time of the reaction slurry is as shown in Table 1.

The - of the slurry is 6.3 to 7.1, and the reaction temperature is 56 to 6.
The temperature was 4°C.

Note that homogeneous compounds E and F were prepared by completely adding tetraglobyl ammonium bromide (TPABr) to an aqueous sodium silicate solution.

The slurry-like product overflowing from the reaction tank was separated into solid and liquid using a centrifugal separator, and after thorough washing with water, wet cakes A to F of homogeneous compounds having the compositions shown in Table 1 of Cylinder 1 were obtained.

No sony was observed in these homogeneous compounds, and all X-ray powder diffraction results showed that they were amorphous. Also, homogeneous compound E
The ratio of TPAB r present in the liquid phase obtained by solid-liquid separation of the slurry products of and F and the liquid phase discharged from the cleaning process was 5% or less relative to the amount of TPAB r added.

Examples 1-12 and Comparative Examples 1-2 The homogeneous wet cake of the compound prepared as described above was added to a solution of tetrapropylammonium bromide and solid sodium hydroxide in water with stirring, and stirred for 30 minutes. A raw material mixture was prepared. This raw material mixture was placed in a No. 11 autoclave and heated to 180° C. while stirring at a circumferential speed of 0 to 8 m/sea to crystallize. The reaction product was then separated into solid and liquid, thoroughly washed with water, and then dried at 110°C. Table 2 shows the raw material mixture composition, crystallization conditions, and results.

Example 13 Pure water 543II was placed in a container, and 9.211% of tetrabutyl bromide (TBABr) and 13.1% of solid sodium hydroxide were added. P and then homogeneous compound A18
After adding 6I with stirring, the mixture was stirred for 30 minutes to prepare a raw material mixture. The composition of the raw material mixture is expressed in molar ratio of oxides as follows: 5IO2/At20. =12O Na20/SiO□=0.125'lI20/5io2=25 (TBA)20/8102=0.01.

This raw material mixture was put into an autoclave of 11 and the circumferential speed was 0.
．． The mixture was heated at 180° C. for 20 hours while stirring at 8 mls@e to crystallize. The reaction product was then separated into solid and liquid, thoroughly washed with water, and then dried at 110°C. The obtained product H5IO2/
The At203 molar ratio was ZSM-11 of 95%. The nitrogen content in the crystallization mother liquor was below 100 m)Pm.

Comparative Example 3 Pure water 5631 was put in a container, tetraglobyl ammonium bromide 11.6N, sodium aluminate (N Hatake 20
: 1 8. 6 wt%, At20
3 two 2 0. Owt La warm; , H2O:
61.4 wt%) 5.5#, solid sodium hydroxide 1
3.7Fi was added, and then white carbon (manufactured by Nippon Sirikani Gyo Co., Ltd., trade name Nip Seal VN-3,5102:
8 7. 7 vrt%, At203
20.5 wt%) 149I was added with stirring. The following composition is added to the composition of this raw material mixture in terms of the molar ratio of oxides: 5IO2/At203=12O N20/8102=0.125 H20/8102=15 (TPA)20/810□=0.01 had.

This raw material mixture was put into an autoclave of 11 and the circumferential speed was 0.
．． The reaction product was crystallized by heating at 180°C for 18 hours while stirring at 8 m/see.Then, the reaction product was separated into solid and liquid, thoroughly washed with water, and then dried at 110°C. The resulting product was ZSM-5 with a crystallinity of 50% and crystalline sodium silicate.

This comparative example shows two cases: one case where crystallization was carried out using amorphous solid silica powder as a silica source, and the other case where crystallization was carried out using a granular amorphous aluminosilicate homogeneous phase compound as a silica source and an alumina source. Here is an example to illustrate the comparison.

Comparative Example 4 Sodium silicate (SiO□: 29.4 wt%, Naz
A solution obtained by adding 200 I of pure water to 187.9' (O: 9.34 wt%) is defined as Solution A. Solution B was prepared by adding 4.9 g of aluminum sulfate 18 hydrate and 14.5.9 Ii of sulfuric acid to 340 I of pure water, and then adding 4.9 Ii of tetrapropylammonium bromide. Mix liquid A and liquid B at the same time.
Stirring was performed for 0 minutes. The composition of this raw material mixture is expressed as the molar ratio of oxides as follows: 5102/At203=
12O N820. /5102=0.125 H20/5iO2=40 (TPA) 20/Sto□=0.01.

This raw material mixture was put into an autoclave of 11 and the circumferential speed was 0.
．． Crystallization was carried out by heating at 180° C. for 16 hours while stirring at 8 m/sec. The reaction product was then separated into solid and liquid, thoroughly washed with water, and then dried at 110°C.

The product obtained was Z SM-5 with a crystallinity of 60%. The nitrogen content in the crystallization mother liquor was approximately 700 ppm.

Claims (1)

[Claims] 1 The following composition expressed in molar ratio of oxides: SiO_2/Al_2O_3=10~∽ M_2_/_nO/SiO_2=0.001~1H_2
O/SiO_2=5-50 R_2O/SiO_2=0.001-0.015 (where M is a metal cation, n is the valence of the metal cation, and R is a quaternary ammonium ion. ), and the silica source and alumina source consist of a granular amorphous aluminosilicate homogeneous phase compound obtained by simultaneously and continuously reacting an aqueous alkali metal silicate solution and an aqueous aluminum-containing solution. A method for producing crystalline zeolite, comprising crystallizing a mixture until crystalline zeolite is produced. 2 The following composition expressed in molar ratio of oxides: SiO_2/Al_2O_3=20~∽ M_2_/_nO/SiO_2=0.001~1H_2
The method for producing crystalline zeolite according to claim 1, wherein a raw material mixture having O/SiO_2 = 7 to 50 and R_2O/SiO_2 = 0.005 to 0.015 is crystallized until crystalline zeolite is produced. 3. The method for producing crystalline zeolite according to claim 1 or 2, wherein the granular amorphous aluminosilicate homogeneous phase compound contains a quaternary ammonium salt. 4 The nitrogen content of the solution obtained by separating the zeolite solid content from the reaction mixture after crystallizing the crystalline zeolite is 500
The method for producing crystalline zeolite according to any one of claims 1 to 3, wherein the amount is less than ppm.