JPS6156166B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the synthesis of novel crystalline aluminosilicate zeolites. More specifically, the present invention relates to a method for synthesizing crystalline aluminosilicate zeolite from a reaction mixture containing an alkali metal compound, allyltripropylammonium, a silicon compound, an aluminum compound, and water.

In general, zeolites are crystals of hydrated aluminosilicate of alkali and alkaline earth metals, and their structure consists of a three-dimensional framework in which Si-O ₄ and AI-O ₄ tetrahedrons share oxygen atoms and extend infinitely. Consisting of The framework of such crystalline zeolites contains interconnected cavities containing pore channels, cations, and water molecules. Water molecules are normally dehydrated continuously and reversibly, but their crystal structure is not destroyed and they become porous adsorbents. Since these pores have a uniform diameter of several angstroms, they exhibit a molecular sieving effect, and only molecules with a molecular diameter smaller than this pore diameter are adsorbed. Such crystalline zeolites are well known as molecular sieves,
Various processes have been industrialized using this property.

The first basic condition for the synthesis of crystalline aluminosilicate zeolite is crystallization from a four-component system of base, silica, alumina, and water.

Conventionally, crystalline aluminosilicate zeolites have been synthesized by various methods, but recently a method using an organic base as a part of the reactant base in this synthesis has been known. This type of synthesis is described in DW Breck, Zeolite Molecule Sieves, published by Wiley Interscience, 1974, pages 304-312.

When synthesized by such a method, a crystalline aluminosilicate zeolite with a high SiO ₂ /Al ₂ O ₃ molar ratio can be obtained, and such a crystalline aluminosilicate zeolite with a high SiO ₂ /Al ₂ O ₃ molar ratio can be synthesized under high heat. It is known to exhibit stability and acid resistance, and to have highly active catalytic ability for hydrocarbon cracking reactions, alkylation reactions, isomerization reactions, etc.

According to the research of the present inventor in this knowledge,
It has been found that crystalline aluminosilicate zeolites with a high SiO ₂ /Al ₂ O ₃ molar ratio can be synthesized by using an alkali metal and allyltripropylammonium as reactant bases. Furthermore, it was surprisingly confirmed that the synthetic crystalline aluminosilicate zeolite obtained by the method of the present invention, upon calcination, adopts a crystal structure clearly different from that of the synthetic form (uncalcined). These properties are unique properties that are completely absent from conventional synthetic crystalline aluminosilicate zeolites.

The crystalline aluminosilicate zeolite of the present invention has a crystal structure characterized by a powder X-ray diffraction pattern having at least the following lattice spacings d (Å) as listed in Table 1 below:

Table 1 Lattice spacing d (Å) Relative intensity 11.2±0.2 strong 10.0± strong 3.85±0.07 strong 3.71±0.05 medium 3.65±0.05 medium These values were measured by standard techniques. A copper K-alpha twin beam was used as the irradiation beam, and a self-recording scintillation counter spectrometer was used.
Peak intensities and peak positions were read as a function of 2θ (θ=Black angle) from the spectrometer chart.
The relative intensity and lattice spacing were calculated from these values.

Note that this powder X-ray diffraction pattern may undergo a change in peak intensity and a slight shift in lattice spacing due to calcination or ion exchange operations. However, such shift changes are included in the range of lattice spacings shown in Table 1.

The present invention provides a method for synthesizing crystalline aluminosilicate zeolite, in which crystalline aluminosilicate zeolite is crystallized from a reaction mixture containing one or more of each of an alkali metal compound, allyltripropylammonium, a silicon compound, an aluminum compound, and water. This method synthesizes crystalline aluminosilicate zeolite at sufficient temperature, time, and pressure.

The crystalline aluminosilicate zeolite synthesized according to the present invention has a high SiO ₂ /Al ₂ O ₃ molar ratio,
Like general crystalline aluminosilica zeolites with a high SiO ₂ content, it can be used as a catalyst for hydrocarbon conversion reactions, such as hydrocarbon cracking reactions, alkylation reactions, and isomerization reactions.

In synthesizing the crystalline aluminosilicate zeolite of the present invention, the silica source can be used in the commonly used forms of silica sol, silica gel, water vitreous, and the like. The alumina source can also be used in the form of commonly used alumina gel, alumina sol, sodium aluminate, aluminum salt, and the like. Furthermore, among the base sources, alkali metals are used in the form of salts or hydroxides, and those that are soluble in water are preferred. Further, the organic base of the present invention is allyltripropylammonium.

In the present invention, a reaction mixture having the following composition expressed in molar ratio is first prepared using the above-mentioned reactants.

SiO ₂ /Al ₂ O ₃ = 5-1000 H ₂ O/SiO ₂ = 5-300 M/SiO ₂ = 0.001-10 R ₂ O/SiO ₂ = 0.01-10 (M represents an alkali metal compound, R represents Allyltripropylammonium) Furthermore, chlorides, bromides and/or sulfates of sodium, potassium and/or barium can be used as mineralizing agents in the reaction of the present invention. These mineralizing agents may be added to or formed in the reaction mixture.

The reaction mixture is carried out at a temperature, time and pressure sufficient to form crystalline aluminosilicate zeolite, the reaction time being in the range of 80°C to 300°C, more preferably 120 to 175°C, and the reaction time being 3. It ranges from hours to 60 days, more preferably from 1 day to 5 days. Although the reaction can be carried out under normal pressure, it is preferably carried out under increased pressure (2 to 15 kg/cm ² ). However, autogenous pressure is sufficient.

The reaction is carried out until crystalline aluminosilicate zeolite is produced, and the reaction mixture is preferably stirred during the reaction.

The crystalline product thus obtained is filtered off, washed with water and separated from the reaction medium. Furthermore, the crystals can be dried and calcined if necessary. For example, drying can be carried out at 110°C for 3 to 24 hours, and baking can be carried out at 200°C to 1000°C, preferably 400°C to 800°C.

The crystalline aluminosilicate zeolite of the present invention is prepared by adding at least a portion of the alkali metal cations in synthetic form, preferably after calcination, to other cations such as hydrogen, hydrogen precursors and groups of the periodic table of the elements. It is also possible to carry out ion exchange with cations or cation mixtures selected from the group consisting of metals of groups up to Group 3.

The method of the present invention will be described in detail below with reference to Examples.

Example 72.58 g of No. 3 water glass containing 28.6% SiO ₂ , 9.3% Na ₂ O and 62.1% by weight
(containing _H2O ) dissolved in 20g of water is A.
Make it into a liquid. Solution B is prepared by dissolving 6.21 g of sulfuric acid and 5.28 g of aluminum sulfate (Al ₂ (SO ₄ ) _{3.18H 2} O) in 20 g of water. 86.87 g of allyltripropylammonium hydroxide (which contains 59.7% by weight H ₂ O) is liquid C.

First, liquid A was placed in a 500 ml Teflon-coated stainless steel autoclave, liquid C was added with stirring, and liquid B was finally added with stirring. The reaction mixture has the following composition in molar ratios:

2.74Na ₂ O: 10.98 (C ₁₂ H ₂₆ N) ₂ O: Al ₂ O ₃ : 43.63 SiO ₂ : 987 H ₂ O: 11.0 Na ₂ SO ₄ This reaction mixture was stirred at approximately 300 rpm for 150 min.
After 7 days of holding at autogenous pressure at 110°C, the resulting crystalline product was filtered off, washed with water, and dried at 110°C for 16 hours. Next, the obtained product was divided into two parts, one part was calcined as it was and the other part was calcined at 540°C for 3 hours, and each part was analyzed by powder X-ray diffraction method (Cu Kα).

The drawing shows a part of the X-ray diffraction diagram, and a in the drawing shows the unfired product (in its synthetic form).
b is the X-ray diffraction pattern of each fired product.
As is clear from the comparison between a and b, the synthetic crystalline aluminosilicate zeolite obtained by the method of the present invention has a peak at 2θ = approximately 23.1°, a peak at 2θ = approximately 23.0°, and a peak at 2θ = approximately 2θ = approximately It can be seen that the peak has changed to 23.2°.

The molar ratio of SiO ₂ /Al ₂ O ₃ in the above-mentioned fired product is
It was 30.

[Brief explanation of the drawing]

The drawings show a part of the X-ray diffraction diagram of the synthetic crystalline aluminosilicate zeolite obtained by the method of the present invention, in which a is the X-ray diffraction diagram of the unfired product and b is the X-ray diffraction diagram of the fired product.

Claims (1)

[Claims] 1. A method for synthesizing crystalline aluminosilicate zeolite, in which crystalline aluminosilicate zeolite is crystallized from a reaction mixture containing one or more of each of an alkali metal compound, allyltripropylammonium, a silicon compound, an aluminum compound, and water. A method of synthesizing crystalline aluminosilicate zeolite at sufficient temperature, time and pressure.