JPS6217015A - Production of alkali cation type crystalline aluminosilicate - Google Patents

Abstract

PURPOSE:To produce the titled high-purity crystalline aluminosilicate which is high in Al2O3 content and available as an adsorbent and a catalyst by changing SiO2/Al2O3 of an aq. raw material mixture for the composition of an aq. mixture in a synthesis process of a seed solid material. CONSTITUTION:A solid material contg. alkali cation type crystalline aluminosilicate is produced by holding an aq. raw material mixture which contains an SiO2 source, an Al2O3 source and alkali metallic salt and is free from an organic additive and has 40-120 molar ratio of SiO2//Al2O3 for 4-500hr in the hydrothermal synthetic conditions (50-250 deg.C). Then alkali cation type crystalline aluminosilicate wherein the peak of ZSM-5 type zeolite crystal is extremely strong and the pattern of mordenite is not almost present is obtained by adding 0.01-3wt% above-mentioned solid material as a seed crystal to the aq. raw material mixture which contains as SiO2 source, an Al2O3 source and alkali metallic salt and is free from the organic additive and has 25-500 molar ratio of SiO2/Al2O3 and holding the mixture at 50-250 deg.C for 4-500hr.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel method for producing an alkali cation type crystalline alumino hepta-silicate. In particular, the present invention uses a raw material mixture containing no organic additives to produce various SiO2/Al2
It relates to a method of manufacturing with a high O3 ratio.

[Conventional technology]

Many crystalline aluminosilicates, such as zeolites, are natural or synthesized. These crystalline aluminosilicates have pores forming a large number of three-dimensional structures, and are used as molecular seeds for adsorbents and gas separation, and recently have also been used for cracking hydrocarbons, hydrocracking, etc. It has come to be widely used as a catalyst for hydrocarbon conversion such as isomerization.

These crystalline aluminosilicates are generally sourced from silica,
It is manufactured by holding an aqueous mixture containing an alumina source, alkali metal salts, etc. under hydrothermal synthesis conditions, which speeds up the crystal growth of the target zeolite and produces a product with high purity (no other crystal systems mixed in). Various organic additives are used to obtain it. For example, ZSM-5 zeolite uses quaternary ammonium salts such as tetrapropylammonium bromide (U.S. Pat. No. 3,702,386, Japanese Patent Publication No. 4G-10064, etc.); The use of various organic additives has also been proposed.

The use of such organic additives has the effect of accelerating the growth of the target zeolite and improving its purity, resulting in a high-quality product, but it is costly and some of them have toxicity problems. There were also some drawbacks. Furthermore, it has been confirmed that when a nitrogen-containing compound is used as an organic additive, the additive remains as an organic contaminant even after the firing operation.

In order to eliminate these drawbacks, methods for producing zeolite without using organic additives have been proposed.

For example, silica, alumina, which does not contain any organic additives,
An aqueous raw material mixture consisting of alkyl metal salts, etc.
There is a method in which zeolite is produced by holding at 0 to 210°C for 40 to 200 hours (% Publication No. 56-49851), and a method in which crystalline zeolite powder is present in an aqueous raw material mixture that does not contain any organic additives such as those mentioned above. A method (Japanese Patent Publication No. 7819/1983) has been proposed in which zeolite is produced by

In the former method, ZSM-5 type zeolite can be obtained without using any organic additives, but mordenite crystals coexist in the crystals, making it impossible to obtain zeolite with good purity. In addition, for the latter, zeolite powder must be prepared as a seed crystal for each production, and the zeolite used as the seed crystal is not prepared using conventional organic additives (e.g., tetrapropylammonium bromide) from the description in the publication. This process requires organic additives. Further, such seed crystals contain organic additives and/or organic impurities, and some of these will remain in the product. Furthermore, the latter method yields crystalline zeolite with good purity, and this is thought to be due to organic substances present in the seed crystals.

The present inventors conducted various studies in order to obtain highly pure alkaline crystalline aluminosilicate without using any organic additives, and first synthesized an aqueous raw material mixture containing no organic additives under hydrothermal synthesis conditions. A solid substance containing alkali cation-type crystalline aluminosilicate is produced by holding the crystalline aluminosilicate at the bottom, and a part of the extremely solid substance is re-presented in an aqueous raw material mixture having the same composition to form a zeolite, thereby producing a highly pure alkali cation. A method to produce crystalline aluminosilicate was proposed. (Unexamined Japanese Patent Publication No. 1983-77123).

[Problem that the invention seeks to solve]

When using the above method, it is possible to obtain a highly pure alkali cation type crystalline aluminosilicate used for adsorbents, hydrocarbon conversion catalysts, etc. without using any organic additives. The composition of the aqueous raw material mixture used in the process is limited, for example, SiO
Seed solids are produced only when □/A1203 (molar ratio) is in the range of 40 to 120. Therefore, when the zeolite obtained in this way is used to produce zeolite in the next step or in a step subsequent to the next step, the composition of the aqueous raw material mixture used together with the seed solid is approximately within the same range as the composition of the above-mentioned mixture. It is believed that the composition must be within this range and is used only within this range, and therefore the composition of the alkali cation type crystalline aluminosilicate that can be obtained is limited.

However, special characteristics may be required for such alkali cation type crystalline aluminosilicate depending on the purpose of use. For example, when used as a hydrocarbon conversion catalyst, coke accumulates on the catalyst and must be treated at high temperatures to burn off the coke in order to regenerate and reuse the catalyst. Since this type of catalyst has better heat resistance when it is rich in silica, it is desirable to increase the content of 8102 in the crystalline aluminosilicate for the above purpose. on the other hand,
If you want to improve the ion exchange ability or catalytic activity without requiring high heat treatment, alumina-rich is better, and for this purpose it is desirable to increase the Al2O3 content of the crystalline aluminosilicate. ing.

[Means for solving problems]

In order to meet the above-mentioned demands, the present inventors have further studied the above-mentioned method and found that the SiO2/Al2 aqueous raw material mixture used in the product manufacturing process in the above-mentioned method
It has been found that even if the O3 ratio is varied within a certain wide range from the composition of the aqueous mixture in the seed solid synthesis step, a highly pure alkali cation type crystalline aluminosilicate that can be used as an adsorbent or catalyst can be obtained.

That is, it contains ZSM-5 type zeolite in which mordenite, etc., obtained by holding an aqueous raw material mixture consisting of a silica source, an alumina source, and an alkali metal and containing no organic additives under hydrothermal synthesis conditions, coexists. A solid material was used as a seed, and it did not contain organic additives, and S10□/
The Al2O3 ratio is different from 51o2/Al2O3 of the aqueous raw material mixture in the seed solid synthesis step, and 25 to 500
When adding zeolite to an aqueous raw material mixture within the range of We succeeded in obtaining highly pure alkali cation type crystalline aluminosilicate containing no mordenite in various SiO2/Al2O3 ratios. Furthermore, even if the same operation was repeated using a part of the product obtained in this way as a seed crystal, the alkali cation type crystalline aluminosilicate with high purity could be converted into various SiO2
/Al2O3 ratio.

The object of the present invention is to produce highly pure alkali cation type crystalline aluminium, which is free from foreign crystals such as mordenite, by using an aqueous raw material mixture consisting of a silica source, an alumina source, and an alkali metal salt, without using any organic additives. The object of the present invention is to provide a method for producing silicates with various StO□/Al2O3 ratios.

That is, the present invention maintains an aqueous raw material mixture containing a silica source, an alumina source, and an alkali metal salt and does not contain organic additives under hydrothermal synthesis conditions to produce a solid material containing an alkali cation type crystalline aluminosilicate. Seed solid substance synthesis step and part of the solid substance containing crystalline aluminosilicate obtained in the synthesis step is used as a seed, and a silica source, an alumina source, and an organic additive containing an alkali metal salt are added to the seed solid substance. and the SiO□/Al2O3 ratio is S10□/Al of the aqueous raw material mixture in the seed solid synthesis step.
Product manufacturing in which an aqueous raw material mixture different from 2O3 and within the range of 25 to 500 (mole ratio) is maintained under hydrothermal synthesis conditions to produce an alkali cation type crystalline aluminosilicate substantially free of organic additives. The present invention is a method for producing alkali cation type crystalline aluminosilicate at various S10°/Al2O3 ratios.

The present invention will be explained in detail below.

As the inorganic raw material used in the present invention, all materials used in the production of crystalline aluminosilicate such as ZSM-5 zeolite can be used.

That is, as a silica source, silica powder, silicic acid, colloidal silica, dissolved silica, etc. are used, as an alumina source, aluminum sulfate, nitrate, etc., sodium aluminate, colloidal alumina, alumina, etc. are used, and As the alkali metal salt, hydroxides of sodium, potassium, rubidium, etc. are used.

The seed solid synthesis step in the present invention uses the above-mentioned inorganic raw materials and the same hydrothermal synthesis conditions as the conventional zeolite synthesis without using any organic additives, that is, the above-mentioned silica source,
Consisting of an alumina source and an alkali metal salt, and 0 SO soil
A solid material containing an alkali cation type crystalline aluminosilicate is produced by holding an aqueous raw material mixture in which 2/Al2O3 is in the range of 40 to 120 at 50°C to 250°C for 4 to 500 hours. In this case, since the solid material obtained usually does not contain organic additives, it has a low degree of crystallinity, as shown in FIG. A low-crystalline aluminosilicate is obtained in which different types of zeolite such as mordenite coexist, having a pattern of zeolite (marked by M) mixed with a pattern of zeolite (marked by 0).

A part of the solid material containing the alkali cation type crystalline aluminosilicate obtained here is used as a seed in the next step, but it may be in the form of a mother liquor gel, dried product, or baked product. .

Next, a part of the solid material containing the alkali cation type crystalline aluminosilicate obtained in this manner is used as a seed, and contains this and the above-mentioned silica source, alumina source, and alkali metal salt, and 51o2/Al2O3 is the seed 51o2/Al of the aqueous raw material mixture in the solid synthesis step
By holding an aqueous mixture with a different 2O3 ratio and in the range 25-500 under hydrothermal synthesis conditions similar to those described above, ZS
The peak of the M-5 type zeolite crystal is very strong, and the alkali cation type crystalline aluminosilicate, which has almost no chimiturn of mordenite shown in Fig. 2, is
It can be obtained with a ratio of 1o2/Al2O3.

In other words, by using a solid material in which the alkali cation type crystalline aluminosilicate contained is low-crystalline and in which different types of zeolite such as mordenite are present, almost no mordenite is present, without using any organic additives. Crystalline aluminosilicates of the alkali cationic type, which do not contain acetate, can be obtained with various StO□ZA12o3 ratios.

Alternatively, the crystal growth as described above may be repeated using the solid material containing the alkali cation type crystalline aluminosilicate obtained in this manner as a seed, or the alkali with good purity may be grown no matter how many times the same operation is repeated. Cationic crystalline aluminosilicates can be obtained with various 810□/Al2O3 ratios.

The seed used in the present invention is a solid material containing an alkali cation type crystalline aluminosilicate obtained in the seed solid synthesis process or manufacturing process or a powder obtained by drying or calcining the alkali cation type crystalline aluminosilicate. However, in order to perform the operation continuously, it is preferable to transfer a part of the mother liquid gel to the next step. That is, a part of the product mother liquor gel taken out from the outlet of a reaction vessel such as an autoclave is returned to the inlet of the same vessel and supplied to the reaction system together with new inorganic raw materials. 81
Production can be carried out continuously with a ratio of 0□/Al2O3.

The present invention may also be operated in a patch manner using one reaction vessel, or may be operated in a semi-continuous manner using two or more reaction vessels.

The amount of seeds used in the present invention is about 0.01 to 3% by weight of the aqueous raw material mixture based on the zeolite in any process. If the amount of seed crystals is too small, a highly pure product cannot be obtained, and if it is too large, the yield will be lowered, which is not preferable.

[Effect of light]

As described above, the present invention does not use any organic additives in all processes and has very high purity, for example, ZSM-5 type zeolite and the alkali cation type crystalline material used as various catalysts. Aluminosilicates can be obtained with various SiO□/Al2O3 ratios.

The present invention will be explained below with reference to Examples.

Example 1 Sodium aluminate (Wako Tsumugi Kogyo g A 73/M a
Dissolve 2.42 g of atomic ratio 0.78) and 9.10.9 of caustic soda (special grade manufactured by Wako Tsumugi Kogyo Co., Ltd.) in 296 g of water, and add 156 y of silica sol solution (Snowtex 30, manufactured by Kagaku Kagaku Kogyo Co., Ltd., manufactured by Kabutsu Kagaku Kogyo Co., Ltd.) to 296 y of water. (diluted) 452
5J was added and mixed to prepare a mother liquid gel.

This mother liquor gel was placed in a Pyrex autoclave and kept under self-generated pressure at 180° C. for 3 days to form a zeolite. After the reaction was completed, the product was filtered and washed three times with 11 portions of distilled water each time. then 1
After drying at 20°C, it was fired at 550°C for 3 hours in an air stream.

This gave a crystalline product (A).

As shown in FIG. 2, the powder X-ray diffraction results of this product showed that the crystallinity of the zeolite was low and that ZSM-5 and mordenite were present in the mixture.

Next, sodium aluminate (AIJ/Na manufactured by Wako Tsumugi Kogyo Co., Ltd.)
Atomic ratio 0.78) 4.84.9. Caustic soda (special grade manufactured by Wako Tsumugi Kogyo) 8.81. lil was dissolved in 296 g of water, and 452 g of a silica sol solution (8san Kagaku Kogyo's Snowtex 30 156y diluted with 296 g of water) was added to the resulting mother liquor gel. 1.9 of product (A) was added and mixed, and zeolite formation was carried out under self-generated pressure at 180° C. in a Pyrex autoclave, and the reaction was stopped in 24 hours. Thereafter, a crystalline product (B) was obtained in the same manner.

The results of X-ray diffraction of this powder showed that the crystallinity of the zeolite was very high, as shown in Figure 1, and the ZSM
-5 only.

When this powder was catalyzed and a methanol conversion reaction was tested, it showed activity selectivity equivalent to that of the ZSM-5 catalyst synthesized using ordinary organic additives.

Example 2 The amounts of sodium aluminate and caustic soda in the product manufacturing process of Example 1 were 1.211.9.2, respectively.
5. A crystalline product was obtained in the same manner as in Example 1 except for FK.

The results of X-ray diffraction of this powder were similar to those shown in FIG. 1, although there were some changes in intensity.

In addition, when attempting to exchange Zn and La metal cations in an alumina-rich product such as the crystalline product obtained in Example 1, the amount of exchange was proportional to the amount of aluminum compared to a silica-rich product. There were many.

In general, it is known that the metal ion exchange ability of zeolite not only indicates the ability of zeolite as an ion exchanger, but also influences the catalytic activity developed thereby, so the alumina-rich zeolite of the present invention has It is clear that it has been improved.

Furthermore, the silica-rich product such as the crystalline product obtained in Example 2 had a slower rate of dealumination from the skeleton by high-temperature steam than the alumina-rich product. When zeolite is used as a catalyst, it may be recycled and used, and its life can be evaluated by a deactivation test using high-temperature steam treatment. It is therefore clear that this silica-rich zeolite of the invention is improved in its properties.

Comparative Example 1 Sodium aluminate (manufactured by Wako Tsumugi Kogyo Co., Ltd. Al/Na atomic ratio 0
．． 78) Dissolve 9.10 g of 2.42N caustic soda (special grade manufactured by Wako Tsumugi Kogyo Co., Ltd.) in water 296I, and add a silica sol solution (Snowtex 3 manufactured by Yasan Kagaku Kogyo Co., Ltd.) to this solution.
00156g diluted with 296g of water) 4521
1 was added and mixed to prepare a mother liquid gel.

This mother liquor gel was placed in a Pyrex autoclave and kept under self-generated pressure at 180° C. for 3 days to form a zeolite. After the reaction was completed, the product was filtered and washed three times with 11 portions of distilled water each time. then 1
After drying at 20°C, it was fired at 550°C for 3 hours in an air stream.

This gave a crystalline product (A).

As shown in FIG. 2, the powder X-ray diffraction results of this product showed that the crystallinity of the zeolite was low and that ZSM-5 and mordenite were present in the mixture.

Next, sodium aluminate (Al/Na atomic ratio 0.78 manufactured by Wako Tsumugi Kogyo) 12.10.91 and caustic soda (special grade manufactured by Wako Tsumugi Kogyo) 7.68.9 were dissolved in 296 g of water,
To this solution, silica sol solution (Snowtex 3001561 manufactured by Yasan Kagaku Kogyo diluted with 296 g of water) 4
52. The above crystalline product (A) 1. is added to the mother liquor gel obtained by adding and mixing P. P was added and mixed, and the mixture was similarly set in a Pyrex autoclave to undergo zeolite formation at 180° C. under self-generated pressure, and the reaction was stopped in 24 hours. Thereafter, a crystalline product was obtained in the same manner.

X-ray diffraction of this powder revealed that it was mordenite with low crystallinity and no ZSM-5 was observed.

Comparative Example 2 Comparative Example 1 except that the amount of caustic soda containing sodium aluminate in the product manufacturing process of Comparative Example 1 was changed to 1.88.
A crystalline product was obtained by the same procedure as above.

X-ray diffraction of this powder revealed that it was a Kenya rock-like substance and no ZSM-5 was observed.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the X-ray diffraction/ξ turn of the crystalline aluminosilicate obtained in the product manufacturing process of the present invention, and Fig. 2 is a graph showing the X-ray diffraction/ξ turn of the crystalline aluminosilicate obtained in the homogeneous solid synthesis process. It is a graph showing a diffraction pattern.

Claims (1)

[Claims] 1) A solid material containing an alkali cation type crystalline aluminosilicate obtained by holding an aqueous raw material mixture containing a silica source, an alumina source, and an alkali metal salt and containing no organic additives under hydrothermal synthesis conditions. A seed solid synthesis step for producing a seed solid, and a part of the solid material containing the alkali cation type crystalline aluminosilicate obtained in the synthesis step is used as a seed, and this and an organic additive containing a silica source, an alumina source, and an alkali metal salt. and the SiO_2/Al_2O_3 ratio is the same as that of the aqueous raw material mixture in the seed solid synthesis step.
A product manufacturing process in which an aqueous raw material mixture having a different Al_2O_3 ratio and within the range of 25 to 500 (molar ratio) is maintained under hydrothermal synthesis conditions to produce an alkali cation type crystalline aluminosilicate. A method for producing alkali cation type crystalline alumina silicate. 2) The product manufacturing process includes at least two steps, and only the first step uses a part of the solid material containing the alkali cation type crystalline aluminosilicate obtained in the solid material synthesis step as a seed, and the following steps are performed. The method for producing an alkali cation type crystalline aluminosilicate according to claim 1), in which a part of the solid material containing the alkali cation type crystalline aluminosilicate obtained in the previous step is used as a seed for the next step. .