JPS6126508A - Removal of alminum from crystalline aluminosilicate - Google Patents

Abstract

PURPOSE:To increase the molar ratio of SiO2/Al2O3, and to carry out the removal of aluminum from a crystalline aluminosilicate in high yield, by the two- stage reaction of a crystalline aluminosilicate with an inorganic halide or an inorganic oxyhalide. CONSTITUTION:A crystalline aluminosilicate is made to contact with an inorganic halide (e.g. SiCl4) or an inorganic oxyhalide (e.g. CrO2Cl2) under the condition to keep the halide, etc. from the reaction with zeolite, i.e. at <=100 deg.C, preferably <=50 deg.C, to effect the permeation and diffusion of the halide, etc. to the core of the zeolite. The crystalline aluminosilicate containing absorbed halide, etc. is heated at >=150 deg.C under atmospheric pressure, and maintained to the state for a definite time interval (1min-50hr) to effect the aluminum removal reaction. The product is cooled, washed with water, and dried to obtain the objective substance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for dealuminating crystalline aluminosilicate, and more particularly, the present invention relates to a method for dealuminating crystalline aluminosilicate, and more specifically, it deals with dealumination of crystalline aluminosilicate by eliminating aluminum from crystalline aluminosilicate to produce crystalline aluminosilicate with a high 5i02/A4203 molar ratio. Concerning how to obtain silicates.

[Technical background of the invention and its problems l Crystalline aluminosilicate has 5i0 in its crystal lattice.
It is a material that has a three-dimensional spatial network structure consisting of 4- and A-4-tetrahedrons, and has hollow chambers with certain dimensions.It is used in a wide range of fields, such as adsorbents and catalysts, and is usually
called zeolite.

Synthetic zeolites such as A type, Y type, X type, L type, and 29M type; natural zeolites such as faujasite, mordenite, and montmorillonite are known.

The structural 5i02/Al2O3 molar ratio is known as one of the factors that determines the properties of this crystalline aluminosilicate. For example, when aluminum is eliminated from the crystal lattice of zeolite to increase the 5i02/A1203 molar ratio, the unit cell of the resulting zeolite shrinks, changing its shape selectivity and increasing its stability against high heat loads and water vapor. .

For this reason, especially in the technical field of manufacturing various catalysts based on zeolite, this 5i02/
Efforts to increase the AJL 203 molar ratio are underway in various ways.

For example, JP-A-57-170818 discloses a method of dealuminating an aluminosilicate and a halogen, an inorganic halide, or an inorganic oxyhalide in a temperature range of 140 to 80°C;
No. 361317 discloses that faujasite-type zeolite and gaseous halogen silane are heated at 150 to 450'C! A method of removing aluminum and increasing its thermal stability by treating the aluminum at a temperature range of Furthermore, a method has been proposed in which NaY-type zeolite is reacted with gaseous silicon tetrachloride at a high temperature of 457 to 557°C (H, Bayer).
, J. Belenkaya; Catalysis
by Zeolites, pp 203).

However, all of these methods selectively dealumate only the surface portion of the zeolite, and are insufficient in terms of removing aluminum as a whole including the interior of the zeolite.
The current situation is that the 3 molar ratio is not very high.

[Object of the Invention] The object of the present invention is to eliminate the drawbacks of the conventional dealumination methods described above, and to provide a method for proceeding dealumination to the inside of crystalline aluminosilicate.

[Summary of the Invention] In the course of intensive research to achieve the above-mentioned object, the present inventors focused on the fact that in all conventional methods, zeolite and halide, etc. are directly reacted at high temperatures from the beginning. did. In other words, in the conventional method, since the dealumination reaction is carried out at high temperatures from the beginning, only the surface portion of the zeolite is selectively modified, and as a result, halides, etc. do not penetrate or diffuse into the zeolite, and the entire surface of the zeolite is modified. It was assumed that the dealumination reaction would not progress. Therefore, if these halides, etc. are allowed to penetrate and diffuse into the interior of the zeolite under conditions in which they do not react with the zeolite, and then the whole is maintained under reaction conditions, the dealumination reaction of the entire zeolite can be carried out smoothly.
The idea of a two-step reaction that proceeds comprehensively led to the development of the method of the present invention.

That is, in the method for dealuminating crystalline aluminosilicate of the present invention, the crystalline aluminosilicate and the inorganic halide or inorganic oxyhalide are brought into contact with each other at a temperature of 100°C or lower, and then maintained at a temperature of +50'0 or higher. It is characterized by cooling and washing with water.

First, the crystalline aluminosilicate to which the method of the present invention can be applied is the A-type and Y-type as described above.

It may be synthetic zeolite such as X type, L type, 23M type, etc. or natural zeolite such as faujasite, mordenite, montmorillonite etc., and is not particularly limited.

In addition, as inorganic halides, 5IC14, Fe0 3pc cross 3. Bc again 3. HgC also 2. PC sentence 5. T
i0 sentence 4 etc. can be mentioned, and f# machine oxyhalide is Cr021LQ 2.5OC5L2. N0
0 sentences 2. [0C512 etc. can be mentioned. Each of these compounds may be used alone, or two or more of them may be used in a suitably mixed state. Furthermore, these compounds are used in gaseous form.

As a method for bringing the crystalline aluminosilicate into contact with these compounds, when the compound is in a gaseous state, a gas of the above-mentioned compound contained in a carrier gas such as nitrogen may be passed through the crystalline aluminosilicate.

It is necessary to control the temperature at this time to below 100°C. Preferably the temperature is 50°C or less.

If this temperature is higher than 100° C., a dealumination reaction begins to occur at the surface portion of the crystalline aluminosilicate, which hinders the achievement of the object of the present invention.

It is thought that in this contact step, the inorganic halide or inorganic oxyhalide penetrates and diffuses into the interior of the crystalline aluminosilicate without causing a dealumination reaction, and waits for the next step.

Next, the crystalline aluminosilicate containing an inorganic halide or inorganic oxyhalide is placed under normal pressure.
It is heated to a temperature of 0° C. or higher and held at that temperature for a predetermined period of time. Only then will the dealumination reaction proceed.

If the temperature is less than 150°C, the reaction will not proceed smoothly.

Preferably the temperature range is 200 to 200 °C. In addition, the holding time is 1 minute to 50 hours, preferably 1 to 2 hours.
It is 0 hours.

If the obtained product is cooled, thoroughly washed with water, and then dried, 5i02/A1120 intended by the method of the present invention can be obtained.
A crystalline aluminosilicate having a molar ratio of 3 is obtained.

[Example 1 of the invention Example 1 Si02/All 203%) Iy ratio is 34 (7)
H-type ZSM-5ze? 5 IL IOg tr-C
5cl 'a degree 0.00?8mo/l//l (7)
The mixture was poured into 200ml of an aqueous solution and stirred for 3 hours at a temperature of 100''C.Then, the cake was filtered and the cake was heated to 120ml.
After drying at 550° C. for 6 hours, it was made into Cs-ZSM-5 zeolite with an exchange rate of 50%.

Next, this Cs-ZSM-5 zeolite was placed in a normal pressure reactor and calcined at 550"O in a nitrogen stream.
The mixture was allowed to cool to room temperature.

Here, silicon tetrachloride diluted with nitrogen (partial pressure 200To
rr) for 10 minutes, then heated to 550°C at a temperature increase rate of 5°C/min and held at that temperature for 15 hours'',
During this period, silicon tetrachloride gas was continued to flow.

The treated Cs-ZSM-5 zeolite was washed with 800ml of distilled water and then placed in 200mu of IN hydrochloric acid at 100°C.

It was treated for 6 hours to form H type. The dealumination rate of the product was 68%, and the 5i02/A203 molar ratio was 112. Further, the acid strength of this product was measured by an ammonia temperature programmed desorption method. The results are shown in Figure 0, where the solid line is for the product obtained by the method of the present invention, and the dotted line is for ZSM-5 (S+02/AfL20334) used as the starting material.

Examples 2 to 6 Various H-type ZSM-5 zeolites were produced by performing the same treatment as in Example 1, except that the type of exchange metal and exchange rate were different, and the holding time at 550°C was different. . These dealumination rates and 5i02/A11
203 molar ratios are collectively shown in Table 1.

For comparison, heat treatment was performed at 550° C. for 3 hours without passing silicon tetrachloride gas, and the obtained results are also listed in Table 1 as a comparative example.

Table 1 Reference Examples Dealuminated ZSM-5 zeolite according to the present invention obtained by the method of Example 1 and molten iron catalyst (manufactured by BASF, 58-10RE [l) were mixed in a weight ratio of 1=1. After filling the mixture into a reaction tube, reduction φ activation treatment was performed according to a conventional method. Then, synthesis gas with a 12/CO molar ratio of 2.0 was passed therethrough to examine the catalytic ability. The reaction conditions were a reaction pressure of 20 kg/cm2. Reaction temperature 330℃,
The WHS V was 1.46 hr-'. The results obtained are shown in Table 2.

For comparison, IZSM-5 (alumina binder 3) was used instead of dealuminated ZSM-5 zeolite.
A catalyst was prepared in the same manner as above except that 5% by weight) was used. Its catalytic ability is also listed in Table 2.

Table 2 [Effects of the Invention] As is clear from the above explanation, according to the method of the present invention, a high dealumination rate is possible, and the 5i02/Ajj 203 molar ratio of crystalline aluminosilicate can be increased ( , Table 1), and it also becomes possible to selectively reduce weak acid sites (Figure).

As is clear from Table 2 of Reference Examples, the crystalline aluminosilicate obtained by applying the method of the present invention has the following properties:
When used as a catalyst, the yield of C5+ or higher hydrocarbons and the proportion of aromatic components in C5+ or higher hydrocarbons do not decrease over a long period of about 150 hours, and the catalyst has a long life.

[Brief explanation of the drawing]

The figure shows H-type Cg-ZS obtained by applying the method of the present invention.
M-5 zeolite (solid line) and its starting material zeolite (
(Dotted line) is a diagram showing acid strength. Wen Ji ('C) −

Claims (1)

[Claims] A crystal characterized in that a crystalline aluminosilicate and an inorganic halide or inorganic oxyhalide are brought into contact at a temperature of 100°C or lower, then maintained at a temperature of 150°C or higher, cooled, and washed with water. Dealumination method for aluminosilicate.