JPH0764552B2 - Zeolite production method - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing zeolite.

[0002]

2. Description of the Related Art Zeolite has been used in various fields due to its adsorptivity and ion exchange action, but recently it has been attracting attention as a catalyst for synthesizing petroleum from natural gas or methanol.

As for synthetic zeolite, a method is known in which Al ₂ O ₃ is mixed with SiO ₂ and reacted with an organic oxide and NaOH, but industrially, SiO ₂ contains high-purity Si of 99 Wt% or more. Silica powder and soda ash are reacted at 1100 ° C or higher to produce cullet, which is crushed to 1
Heat to 50 ° C. to form water glass. The water glass is reacted with an Al compound to finally produce a synthetic zeolite which is an aluminosilicate.

[0004]

However, in such a production method, since the starting material is expensive and the production is complicated due to the two-step production method, the synthetic zeolite is inevitably expensive. , The development of a low-cost industrial manufacturing method of zeolite was desired.

The present invention has been made in view of the above, and provides a method for producing zeolite which is suitable for mass production, is economical, and has excellent characteristics.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a method for producing a zeolite from a natural silica stone material, in which Al ₂ O ₃ /
A step of preparing a powder of a natural silica stone stone material having a SiO ₂ ratio (mol / mol) of 1 to 20 × 10 ⁻³ , and mixing the obtained powder with an organic cation compound, NaOH and H ₂ O, under pressure. The present invention provides a method for producing zeolite, characterized in that the zeolite is directly synthesized from natural silica stone material, which comprises a step of hydrothermal treatment.

[0007]

[Function] For example, natural silica stone produced in Iwo Jima, Kagoshima Prefecture, contains SiO ₂ containing an average of 1.40 Wt% of Al ₂ O ₃ component.
Silicon-containing rock with a component of 95 Wt% or less, other F
e, Ti, Ca, Mg, Na, K, and loss on ignition are included. This rock is pulverized to a powder of 100 μm or less, preferably 50 μm or less, which is easily dissolved in NaOH, to prepare an organic cation compound such as tetra-n-propylammonium bromide ((CH ₃ CH ₂ CH ₂ ) ₄ N · Br).
(Abbreviation TPABr) and NaOH solution are added and hydrothermal synthesis is performed under pressure (-100 atm). Hydrothermal temperature is 160
The reaction time is 3 to 72 hours at -300 ° C. After the hydrothermal reaction, the solid product was removed by filtration and dried by heating in air to produce a powdery zeolite (hereinafter, the zeolite obtained by the synthesis is referred to as ZMS-5). The constituents other than SiO ₂ and Al ₂ O ₃ contained in the rock had no chemical effect on the synthesis. This ZSM-5 is (TPA)
-Na type ZSM-5, in which (TPA) (tetrapropylammonium) and Na perform charge compensation for Al substitution of Si in ZSM-5. Furthermore, by heating (TP
A) decomposes to give Na-type ZSM-5. Further H
Substitution of Na ions by ions and absorption of H ₂ O gives H-type ZSM-5.

Organic cation compounds include tetrapropylammonium hydroxide (TPABr) in addition to TPABr.
OH), tetrapropylammonium cation, n-butylamine, tetra-n-propylphosphonium salt, alcohol amines and the like can be used.

The natural silica rock material is Al as a chemical component.
The ₂ O ₃ containing 0.18 to 2.8 wt% _Al 2 _O 3 / Si
O ₂ ratio (mol / mol) is 1 × 10 ^{−3 to} 20 × 10
^A zeolite having a range of ⁻³ can practically synthesize zeolite with a high yield, and the synthesized zeolite is SiO ₂ / Al ₂ O ₃
It is a low molar ratio of ZSM-5 with a ratio of 44-431, has many acidic points, and has advantageous properties for adsorption properties and catalyst properties.

[0010]

EXAMPLES The present invention will be described below with reference to examples.

(Example 1) Silicon-containing rock (hereinafter referred to as IIS) produced from Iwo Jima, Kagoshima Prefecture, which is a starting material, is cristobalite (SiO ₂ ), tridymite (SiO ₂ ).
And a small amount of alunite ((KNa) Al ₃ (SO ₄ ).
The chemical composition of IIS particles containing ₂ (OH) ₆ ) as a crystalline phase (by X-ray diffraction) and dried at 110 ° C. for 24 hours is as follows.

2.95 ignition loss, 94.16 SiO ₂ ,
1.40Al ₂ O ₃ , 0.36Fe ₂ O ₃ , 0.81T
iO ₂ , 0.17CaO, 0.05MgO, total 99.
80 (molar ratio _{SiO 2 / Al 2 O 3 =} 114).

First, an IIS powder having an average particle size of 44 μm was prepared, and TPABr and an oxide composition of (a (TPA)) were prepared.
₂ · bNa ₂ O · Al ₂ O ₃ · cH ₂ O, where a =
2.72-36.7, b = 14.2-28.4, c = 1
A mixture of TPABr of 510 to 6620) and an aqueous solution of NaOH was placed in a heat-resistant container of fluororesin, that is, Teflon (trade name), and heated at 160 to 220 ° C. for 3 to 72 hours in an autoclave. After the hydrothermal reaction, the solid product was removed from the solution by filtration and dried in air at 110 ° C for 8 hours.

The formation ratio of ZSM-5 in the powder thus obtained is changed by variously adjusting the concentrations of TPABr and NaOH.

That is, the as-produced powder phase was subjected to X-ray diffraction (CuKα, type No. 20) at a scanning speed of 2 ° / min.
13 Rigaku Denki Co., Ltd.). Z in powder solids
The SM-5 formation ratio (f (z)) is (501) of ZMS-5.
Plane and Cristobalite (crystal phase existing in the raw material) by the X-ray diffraction intensity ratio with respect to the (101) plane, and f (z) = Iz (501) / (Iz (501)
Since + Ic (101)), the larger f (z), the higher the yield of ZSM-5. The chemical composition of the solid product was investigated by X-ray fluorescence (Rh) of 50 kV (System 3080-E, Rigaku Denki Co., Ltd.). This gives about 200 mg of powdered product to 4.5 g of Li.
₂ B ₄ O ₇ and the mixture is melted to form glass spheres having a diameter of 35 mm.
The e, Ti, Na, and K contents are chemically analyzed. TG and DTA analysis of product (PTC-10A format, Rigaku Denki Co., Ltd.) 100 at a temperature rise rate of 10 ° C / min.
It went to 0 degreeC. The texture of the product was observed with a scanning microscope (H-700H, Hitachi, Ltd.) of 75 kV.

Results of Hydrothermal Synthesis of ZSM-5 of this Example (a) Reaction Time and Solid Product FIG. 1 shows starting composition (molar ratio) 2.74 (TPA) ₂ O-
_{24.6Na 2 O-Al 2 O 3} -114SiO 2 -15
IIS when the system of 30H ₂ O was reacted at 220 ° C
The reaction time dependence of the weight ratio (yield) of the solid product, the phase relationship, and the SiO ₂ / Al ₂ O ₃ molar ratio of the product is shown. The general formula of proton type zeolite is H _x Si
_(1-x) Al _x O ₂ , but with (TPA) and N in the H part
It is a structure in which a is substituted.

As is clear from the figure, the yield gradually reached a constant value (about 0.55) with the reaction time after a short sharp drop in 3 hours. When synthesized without adding TPABr for comparison, the yield of solid product without ZSM-5 after hydrothermal reaction at 220 ° C. for 12 hours was 33.
%Met. This value is close to the yield of 3 hours in FIG. The results and the phase relationship shown in FIG. 1 are as follows: (1) about 60 wt% of IIS dissolves within 3 hours at 220 ° C. (2) ZSM-5 is formed by the following two processes ( a) IIS-TPABr-NaOH- H 2 O system in the solid - liquid reaction, and, (b) dissolving SiO ₂ component, TP
Crystal formation from a liquid phase containing ABr and NaOH.

The increase in the SiO ₂ / Al ₂ O ₃ ratio with the passage of time is accompanied by an increase in the yield and the amount of ZSM-5, which reflects the crystallization of ZSM-5 from the liquid phase. is doing. Wet analysis of Al ³⁺ and Fe ³⁺ by chelate titration on the filtrate after 12-72 hours of reaction showed that 99.0-100% of these ions of starting IIS remained in the formed ZSM-5 zeolite. Shows. Results above, starting IIS and 220 ° C 72
SiO ₂ between ZSM-5 formed after reaction for time
/ _Al 2 _{O 3} molar difference between the SiO ₂ in IIS the ratio 54
% Is used for the formation of ZSM-5, SiO ₂ of 46% indicates that has stopped in solution.

(B) NaO for the formation of ZSM-5
Effect of H and TPABr Concentrations In the reaction at 220 ° C. for 12 hours, FIG.
The effect of H concentration is shown. Increasing the NaOH concentration above 1.2 mol / l accelerates the dissolution of IIS (A) and forms soluble sodium silicate. The TPABr component ratio is f
If (T), then f (T) = (TPABr) / ((TP
ABr) + (NaOH)), and as can be seen from the figure, the influence on the dissolution of IIS was small. On the other hand, ZSM
The formation ratio of −5 depends on the concentrations of both NaOH and TPABr. When f (T) = 0, ZSM-5 is not formed at 220 ° C. As seen in FIG. 2B, ZSM
The amount of −5 increased with the increase of the NaOH concentration and f (T) value (TPABr concentration). However, at a high f (T) value of 0.5 or more, the formation ratio f (Z) of ZSM-5 shows the maximum value at a certain NaOH concentration. F here
(Z) is ZSM-5 (Iz) and cristobalite (I
It is represented by the X-ray diffraction intensity ratio of c), and f (Z) = Iz (50
1) / (Iz (501) + Ic (101)).

Comparing FIG. 2A and FIG. 2B,
(1) The reaction between the SiO ₂ component forming ZSM-5 and NaOH does not completely proceed at a concentration [NaOH] = 1.4 mol / l or less, and (2) a low f (T) of 0.2 or less. The decrease in the amount of ZSM-5 at the () value is in addition to the retardation of the crystallization of ZSM-5 from concentrated NaOH solution (Fig. 1).
It is attributed to the lack of template effect of TPABr to form 5.

[0021] These phenomena (1) and (2), partial destruction of the SiO ₂ tetrahedral SiO bond by Na ₂ O in the glass forming (non-bridge butyrate-containing) and _Na 2 O-SiO ₂
-M _x O _y system: similar to crystallization of the glass at (M cation). The presence of a maximum of ZSM-5 formation ratio to NaOH concentration at high f (T) values and N corresponding to the maximum formation ratio of ZSM-5 to high concentrations with decreasing f (T) values.
The shift of aOH concentration to the higher concentration side is TPA at 220 ° C.
It may be associated with the solubility of Br. Surface coating of IIS with undissolved TPABr is
The chemical reaction with aOH is prevented, so that the formation ratio of ZSM-5 may not reach 100%. The solubility of TPABr at 220 ° C. is estimated to be 1.2-1.3 mol / l from the maximum formation ratio of ZSM-5 in FIG. 2 (B).

(C) Chemical composition of the solid product FIG. 3 shows the SiO ₂ , Al ₂ O ₃ and Na ₂ O contents of the solid product after the hydrothermal reaction at 160 ° -220 ° C. and heating to about 1000 ° C. The subsequent loss on ignition is shown as a function of the formation ratio of ZSM-5. Based on the analysis of some TG-DTA data of the product, the loss on ignition observed below and above about 350 ° C. was interpreted as due to evaporation of H ₂ O and decomposition of (TPA) ₂ O, respectively. It SiO
The structural change from ₂ to ZSM-5 is SiO ₂ and H ₂ O.
It is accompanied by a decrease in content and an increase in (TPA) ₂ O content.
The changes in the components of Al ₂ O ₃ and Na ₂ O due to the formation of ZSM-5 were small as shown in FIG. Increase in the ZSM-5 due to the formation of _{(TPA) 2} O and Na ₂ O have shown that have a critical role in these components make ZSM-5 structure.

FIG. 4 shows 22 as a function of NaOH concentration.
0 shows the _SiO 2 / _Al 2 _{O 3} ratio of the product after the hydrothermal reaction at ° C.. SiO ₂ / _Al 2 _{O 3} molar ratio in the reaction using a high concentration NaOH solution was reduced. This tendency is shown in Figure 2.
It can be compared with the results shown in (A). Increasing the NaOH concentration promotes dissolution of the SiO ₂ component of IIS. But I
Most _Al 2 _{O 3} component of the IS is included in the ZSM-5. As a result, the SiO ₂ / Al ₂ O ₃ ratio strongly depends on the NaOH concentration. _Further, SiO 2 / _Al 2 _{O 3} molar ratio was increased to products with high ZSM-5 forming ratio (Figure 1). This result is explained by the crystallization of ZSM-5 from the liquid phase. _Thus, SiO 2 / _Al 2 _{O 3} molar ratio is governed by the formation ratio of the concentration of NaOH and ZSM-5. Fig. 5 shows amorphous Si in IIS in NaOH solution.
O shows a wide range ZSM-5 of the control of the _SiO 2 / _Al 2 _{O 3} molar ratio of due _{to 2} adding powder or NaAlO _2.

As a result of conducting the experiment at 220 ° C. for 24 hours, all the solid products were only ZSM-5 by X-ray diffraction. Z
The yield of SM-5 increases as the starting material Al ₂ O ₃ / SiO ₂ molar ratio increases, as shown in FIG.
The accelerating effect of the Al ₂ O ₃ component on the crystallization of ZSM-5 from the liquid phase is implied. ZSM-5 Al ₂ O ₃ /
The SiO ₂ ratio was 1.3 to 1.9 times that of the starting material (FIG. 5 (B)).

As shown in FIG. 5B, Al of ZSM-5
_{The change of the 2} O ₃ / SiO ₂ ratio with respect to the starting material decreases linearly with the increase of the Al ₂ O ₃ / SiO ₂ ratio of the starting material. This result is related to the yield of ZSM-5. The decrease in yield at low Al ₂ O ₃ / SiO ₂ ratio of the starting material indicates dissolution of a large amount of SiO ₂ component (FIGS. 2 and 4), and ZSM-5 Al ₂ O ₃ / SiO _{2
The 2} ratio increases as the starting Al ₂ O ₃ / SiO ₂ ratio decreases.

IIS-TPABr according to an embodiment of the present invention
_{-NaOH-H 2} O system and amorphous _{SiO 2} -NaAlO 2 -TPABr-NaOH prepared experimentally for comparison
_Al 2 of ZSM-5 between -H ₂ O system _O 3 / SiO ₂
The difference in the ratio is that the starting material Al ₂ O ₃ / SiO _{2 in} FIG.
_It can be compared by the numerical value of the molar ratio of ₂ = 8.77 × 10 ⁻³ .
The former system using IIS is amorphous SiO ₂ and NaAl
Higher Al ₂ O ₃ / compared to the latter system using O _2.
This gives a ZSM-5 ratio of SiO ₂ . In the former system, the low yield is one of the reasons for the high Al ₂ O ₃ / SiO ₂ ratio.

(D) Morphology of ZSM-5 zeolite System 13.9 (TPA) ₂ O · 14.2 obtained by carrying out
Na ₂ O ・ Al ₂ O ₃・ 114SiO ₂・ 6540H ₂
Changes in the morphology of solid products due to the hydrothermal reaction temperature for O
When observed by EM (scanning electron microscope), diluted Na
Low (160 ° -1) in OH solution (0.24 mol / l)
The products at 80 ° C.) and at high (200 ° -220 ° C.) temperatures are made up of 1-2 μ monodisperse spherical or square particles and agglomerates of square primary particles in the submicron size range, respectively. There is. From the above-mentioned changes in the shape and size of the product of ZSM-5 and the formation ratio (shown in FIG. 3) with the reaction temperature, the following conclusions can be drawn.

(1) IIS and NaOH at high reaction temperature
An increase in the reaction rate between and accelerates the dissolution of SiO ₂ .
(2) II with increasing concentration of SiO ₂ component and temperature rise
(3) Particles of each ZSM-5 particle, in which the structural change of S accelerates the nucleation of ZSM-5 and forms uniform nucleation in the solution and partially destroyed IIS non-oriented nuclei. High nucleation rate of ZSM-5 and dilute NaOH at high growth temperature
Suppressed due to the poor supply of SiO ₂ component in the solution.

On the other hand, from the observation of SEM, high concentration of NaOH
Large square ZSM-5 particles of about 5 μm are formed in the solution. In addition, an increase in the concentration of TPABr causes an increase in aggregate ZSM-5.
Was found to promote the formation of High concentration of NaOH
Growth of ZSM-5 particles in solution results in dissolution of Si
It is estimated that TPAB is due to sufficient supply of O ₂ component.
The formation of aggregated ZSM-5 associated with increasing r concentration is ZS
It is presumed to be due to high nucleation of M-5.

Furthermore, Al ₂ O for ZSM-5 growth
_For the effect of ₃ , the reduction of the starting Al ₂ O ₃ (1) reduces the size of the ZSM-5 particles and (2) results in the formation of irregularly shaped ZSM-5 particles. That is, the increase in the amount of Al ions promotes the grain growth of the prismatic ZSM-5.

The (TPA) -generated in this embodiment is
The role of Na and TPA in the formation of Na-type ZSM-5 compensates for the difference in charge associated with Al ions displacing Si ions forming Si-O tetrahedra.

H ₂ O is released by heating, and (TPA) ₂ O is thermally decomposed and released by further heating.
M-5 is obtained. After TPA escapes, it becomes vacancies and contributes to increase in specific surface area. Na-type ZSM-5 is an H-type ZS by substitution of Na ions with H ions and absorption of H ₂ O.
It can be changed to M-5.

As an example, TPA hydrothermally synthesized in this example
-Na-type ZSM-5 obtained by heating Na-type ZSM-5 at 540 ° C for 3 hours is immersed in a 0.5 mol / l HCl solution to immerse Na-type ZSM-5 at 45 ° C to 85 ° C for 1 to 168 ° C. Reflux for hours. As a result, after 24 hours, 89.7% at 45 ° C.
The exchange ratio was 99.0% at 85 ° C.
The obtained H-type ZSM-5 is thermally very stable and is 1100.
A high specific surface area of 300 m ² / g or more is maintained even at ° C.

SiO produced by the manufacturing method of this embodiment.
₂ / Al ₂ O ₃ ratio 70.5 H-type ZSM-5 and SiO ₂
When H-type ZSM-5 having an A / Al ₂ O ₃ ratio of 66.4 was used as a catalyst, an attempt was made to synthesize methanol with gasoline at 370 ° C. (1) Methanol had a carbon number of 1-1 for up to 5 hours.
Completely converted to 0 hydrocarbons (maximum test time),
(2) About 60 Wt% of the produced hydrocarbon has 6-1 carbon atoms
And (3) the weight ratio of the aliphatic compound and the aromatic compound to the carbon number 6-10 is about 40:60.
Met.

From the above, the H-type ZSM synthesized from IIS
The high quality of the -5 catalyst was demonstrated.

Example 2 The IIS powder was mixed with the NaAlO ₂ powder so that the total content in terms of Al ₂ O ₃ was 2.8 Wt.
The powder was prepared so as to be%.

This is because the Al ₂ O ₃ / SiO ₂ ratio is 1 in FIG.
It shows that it is 6.7 × 10 ⁻³ (mol / mol).

When this raw material was hydrothermally treated under the same conditions as in Example 1, zeolite was obtained with a high yield of 70%.

(Example 3) TPABr in Example 1
Instead, tetrapropylammonium (TPAOH) was used as an organic cation oxide and hydrothermal reaction was performed under the same conditions to obtain (TPA) -Na type ZSM-5.

Example 4 Amorphous SiO ₂ was added to IIS powder.
A powder was added to prepare a raw material having an Al ₂ O ₃ / SiO ₂ ratio of 1 × 10 ⁻³ , and hydrothermal treatment was performed under the same conditions as in Example 1. The yield was about 60% (TPA) -Na type ZSM-5. Was obtained (FIG. 5).

As described above, according to the present invention, the molar ratio Si
_{O 2 / Al 2 O 3 =} 61 to 75 ZSM-5 zeolite Iwo silicon-containing rock (IIS) - organic cation compound _{-NaOH-H 2} O system in a solid - liquid containing dissolved SiO component and the liquid reaction It is hydrothermally synthesized by crystallization of ZSM-5 from the phase.

All the Al ₂ O ₃ components in the raw material are incorporated into ZSM-5.

Unnecessary increase in NaOH concentration is caused by ZSM-
5 of yield and reducing the _SiO 2 / _Al 2 _{O 3} molar ratio. It is desirable to select in the range of 0.2 to 2.0 mol / l.

Undissolved TPABr above the solubility is Z
Inhibits the formation of SM-5. The solubility is up to 1.3 mol / l at 220 ° C.

The molar ratio of the raw materials is amorphous SiO ₂ or Na.
It can be prepared by adding AlO ₂ into IIS. The produced ZSM-5 has an Al ₂ O ₃ / SiO ₂ ratio of Al as a starting material.
It decreases linearly with an increase in the ₂ O ₃ / SiO ₂ ratio.
_Al 2 _O 3 / SiO ₂ ratio of product ZSM-5 is 1.3 to 1.9 times the _Al 2 _O 3 / SiO ₂ ratio of the starting material.

Molar ratio SiO ₂ / Al ₂ O ₃ = 61 to 7
The ZSM-5 zeolite of No. 5 has a reverse ratio of Al ₂ O ₃ / SiO ₂
Is high and the substitution amount of Al with respect to Si is relatively large, so that there are many acidic points that bind to ions and the ion exchange property is also high. Moreover, since many (TPA) ions also bind,
At the stage of converting (TPA) into Na-type ZSM-5 by thermal decomposition, the part where TPA is located becomes a vacancy, and ZSM-5 with a large specific surface area is obtained, and ZSM with high activity such as adsorption of gas etc. -5 is obtained.

[0047]

According to the present invention, zeolite can be synthesized directly from natural silica stone in one step, and synthetic zeolite can be economically obtained due to the availability of natural stone and the simple manufacturing method. it can.

Moreover, the obtained zeolite is a high SiO ₂ content zeolite, has many acidic points, has a large specific surface area, and exhibits excellent ion exchange characteristics and adsorption characteristics.

[Brief description of drawings]

FIG. 1 2.74 according to the present example produced at 220 ° C.
_{(TPA) 2 O-24.6Na 2} O-Al 2 O 3 -11
4SiO ₂ -1530H ₂ O system phase relationship (A),
Shows the reaction time dependence of the yield of the solid material to the IIS (weight ratio) (B), and products _SiO 2 / _Al 2 _{O 3} molar ratio of (C).

FIG. 2: Yield (A) of solid material and formation ratio (f (Z)) of ZSM-5 in hydrothermal reaction at 220 ° C. for 12 hours.
The effect of NaOH concentration on (B) is shown.

FIG. 3 shows the chemical composition of solids after a hydrothermal reaction from 160 ° C. to 220 ° C. as a function of the formation ratio (f (Z)) of ZSM-5.

FIG. 4: 220 ° C., 10 as a function of NaOH concentration
SiO ₂ / Al ₂ of solid material after hydrothermal reaction for 12 hours
The O ₃ ratio is shown.

FIG. 5: Yield (A) for hydrothermal reaction at 220 ° C. for 24 hours as a function of SiO ₂ / Al ₂ O ₃ molar ratio of the starting material, and Al ₂ O ₃ of ZSM-5 for the starting material.
/ SiO ₂ molar ratio (B) is shown.

Claims (1)

[Claims] 1. A method for producing zeolite from natural silica stone material, wherein Al2 O3 is 0.18 to 2.8 wt%.
Hints Al2 O3 / SiO2 ratio (mol / mol) 1 × 1
It comprises a step of preparing a powder of a natural silica stone material containing 0 ^{-3 to} 20 x 10 ^-3 , and a step of mixing the obtained powder with an organic ionic compound, NaOH and H 2 O, and subjecting it to hydrothermal treatment under pressure. , A method for producing zeolite, characterized in that zeolite is directly synthesized from natural stone