JPH0321483B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to novel crystalline aluminosilicates. In particular, the present invention relates to novel aluminosilicates synthesized by using specific raw material compositions. Many natural and synthetic crystalline aluminosilicates are known. These crystalline aluminosilicates are mainly SiO ₄ and AlO ₄
SiO ₄ and AlO ₄ have a tetrahedral arrangement structure cross-bonded through oxygen atoms. Such crystalline aluminosilicate has pores forming a large number of three-dimensional structures, and is used as a molecular sieve as an adsorbent and for the separation of hydrocarbons and gases, but recently zeolites with a unique structure have been developed. Since the development of crystalline aluminosilicates such as various ZSM series represented by ZSM-5 (U.S. Pat. No. 3,702,866), they have been used for hydrocarbon transformations such as hydrocarbon cracking, hydrocracking, and isomerization. It has become widely used as a catalyst, and more and more research and development is being conducted in this field. ZSM-5 consists of alumina _, silica _{, alkali metal oxide} , tetraalkylammonium compound _, and water. ₂ 0.01 to 2.0 (where M is an alkali metal ion and R is a tetraalkyl ammonium cation having an alkyl group containing 2 to 5 carbon atoms).
It is produced by keeping the zeolite at a temperature of 10°C until it forms zeolite crystals. Such crystalline aluminosilicates have the following formula: 0.9±0.2M ₂ O:Al ₂ O ₃ :xSiO ₂ :yH ₂ O (where M represents an alkali metal, x is at least 5, and y is 0). ~40) oxide composition. Further, ZSM-5 has a characteristic structure shown in Table 1 below as a powder X-ray diffraction pattern.

[Table] These known crystalline aluminosilicates, including ZSM-5 zeolite, are mainly synthesized under hydrothermal synthesis conditions using raw material mixtures with specific compositions such as an alumina source, a silica source, an alkali metal salt, an organic nitrogen-containing cation source, and water. Manufactured by holding it down. In order to improve known crystalline aluminosilicate such as ZSM-5, the present inventors conducted various studies on the raw material mixture composition, etc., and as a result, they used rubidium as the alkali metal and increased the amount of alkali metal salt added than before. By using a raw material mixture with a specific composition, we succeeded in obtaining a new crystalline aluminosilicate having an X-ray diffraction pattern different from that of conventionally known crystalline aluminosilicates, and achieved the present invention. That is, the present invention provides a silica source, an alumina source,
It consists of an alkali metal salt and a quaternary alkylammonium salt, and has the following composition aM ₂ O: Al ₂ O ₃ : bSiO ₂ : cR ₂ O (where M is rubidium, a is larger than 4.5, and b
is greater than 15 and c is a number greater than 0) is a crystalline aluminosilicate produced by holding an aqueous raw material mixture under hydrothermal synthesis conditions, and the sintered product at 500°C is This is a crystalline aluminosilicate characterized by having an X-ray diffraction pattern shown in Table 2 below.

【table】

[Table] In the present invention, by using potassium as the alkali metal salt in the raw material composition and creating the specific raw material composition as described above, a new crystal having a unique X-ray diffraction pattern as shown in Table 2 can be obtained. However, when sodium or lithium is used as the alkali metal, only those similar to known crystalline aluminosilicates such as ZSM-5 zeolite can be obtained even with the above raw material composition. As other raw material components used in the present invention, the same raw materials as those used in producing known crystalline aluminosilicate such as ZSM-5 are used. That is, as the silica source in the raw material composition, powdered silica, colloidal silica, water glass, silica gel, a commercially available aqueous dispersion of precipitated silica, etc. are used. Alumina sources include alkali metal or alkaline earth metal aluminates, alumina, barite,
Water-soluble aluminum salts, kaolinite, attapulgite, illite, hallosite, etc. are used. In addition, the quaternary alkyl ammonium cation is used to promote the growth of the desired crystal and to prevent contamination with crystals such as mordenite.
Examples include tetramethylammonium, tetraethylammonium, tetrapropylammonium, and tetrabutylammonium, and these are added as halides such as bromides and chlorides, hydroxides, or sulfates. Among these, tetramethylammonium salt is particularly preferred. Rubidium salts include rubidium hydroxide,
Although halides, sulfates, hydrochlorides, etc. are used, hydroxides are particularly preferred. Crystallization is carried out by heating an aqueous raw material mixture having the above-mentioned composition under hydrothermal synthesis conditions, usually between 100°C and 250°C.
by holding under autogenous pressure for 4 to 500 hours at a temperature of . The crystalline zeolite of the present invention, like ZSM-5 zeolite, can be used as a catalyst for hydrocarbon conversion, an adsorbent, and the like. Next, examples will be shown in which the crystalline silicate of the present invention is produced. Example: When 0.94 mol of rubidium hydroxide is dissolved in 150 c.c. of distilled water, 9.63 g of silicon (Si) is added thereto, and the water solution is kept at 60-80°C for about 12 hours, most of the silicon is dissolved. was dissolved and a small amount (approximately 0.01 g) of precipitate was formed, which was removed by filtration to obtain an aqueous solution of rubidium silicate. Add 4.8 g of NaAlO ₂ to this solution and add 60 g of NaAlO 2 in water solution.
It was kept at ℃ for about 1 hour. This operation yields NaAlO ₂
was dissolved, but some white colloidal material was formed. Next, this solution was mixed in a mixer with a solution prepared by diluting 481.2 g of colloidal silica and Snowtex 30 (trade name, manufactured by Nissan Chemical Industries, Ltd.) with 343.8 cc of distilled water, and this was further mixed with an aluminum chloride solution ( 37.5 g of AlCl ₃ and 325 g of H ₂ O) were added to obtain an aqueous gel. The aqueous gel obtained as above is dissolved in water.
After keeping it at 100℃ for 0.5 hours, it was filtered under reduced pressure.
A mixture cake of g was obtained. Next, the water-containing cake obtained in this way 100
17.5 g of a 10% aqueous solution of tetramethylammonium hydroxide and, if necessary, a solution of 0.05 mol of rubidium hydroxide dissolved in about 30 c.c. of distilled water to obtain an aqueous raw material mixture. The raw material mixture thus obtained was maintained under autogenous pressure at a temperature of 180° C. for about 3 days under crystal formation conditions to obtain the crystalline aluminosilicate of the present invention. The obtained crystalline aluminosilicate is
The product fired at 500°C had an X-ray diffraction pattern as shown in Table 3.

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【table】

Claims (1)

[Claims] 1 Consists of a silica source, an alumina source, an alkali metal salt, and a quaternary alkyl ammonium salt, and has the following composition: aM ₂ O: Al ₂ O ₃ : bSiO ₂ : cR ₂ O (where M is rubicium, a is greater than 4.5, b
is greater than 15 and c is a number greater than 0) under hydrothermal synthesis conditions. A crystalline aluminosilicate characterized by having an X-ray diffraction pattern shown in the table below. [Table] [Table] 2. The crystalline aluminosilicate according to claim 1, wherein the quaternary alkyl ammonium salt is a tetramethylammonium salt.