JPH0797207A - Hydrogen-type crystalline metallosilicate having heat resistance and method for producing the same - Google Patents

Abstract

(57) [Summary] [Object] To provide a hydrogen-type crystalline aluminosilicate having heat resistance. [Structure] The hydrogen-type crystalline aluminosilicate contains Na, and the content ratio C _{1 of the} Na is set to C ₁ ≦ 450 ppm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant hydrogen type crystalline metallosilicate and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a crystalline aluminosilicate has been known as a crystalline metallosilicate, and this crystalline aluminosilicate is used, for example, in a catalyst for purifying exhaust gas (for example, JP-A-4-210243). (See Japanese Patent Publication).

[0003]

However, conventional general crystalline aluminosilicates have low heat resistance, and therefore have extremely low durability when exposed to high temperature exhaust gas.
There was a problem.

This decrease in heat resistance is considered to be due to the following reasons. That is, as a synthetic raw material of the crystalline aluminosilicate, since oxides, hydroxides, various salts containing alkali metals and alkaline earth metals are used, when the crystalline aluminosilicate is exposed to high temperatures, For example, Na contained in the synthetic raw material reacts with crystal water of crystalline aluminosilicate to generate Na oxide or Na hydroxide, and the Na oxide or the like constitutes the three-dimensional skeleton structure of crystalline aluminosilicate. Al that is present is eluted, and as a result, the three-dimensional skeleton structure is destroyed.

In view of the above, it is an object of the present invention to provide the above hydrogen-type crystalline metallosilicate and a method for producing the same, in which the heat resistance is remarkably improved by specifying the content of an alkali metal or the like.

[0006]

The heat-resistant hydrogen-type crystalline metallosilicate according to the present invention is one or more metal elements selected from alkali metals, or one or more metal elements selected from alkaline earth metals. At least one of the metal elements is contained, and the content rate C ₁ of the metal element is set to C ₁ ≦ 450 ppm.

The method for producing a heat-resistant hydrogen-type crystalline metallosilicate according to the present invention comprises one or more metal elements selected from alkali metals or one or more metal elements selected from alkaline earth metals. Of at least one of the metallic elements, and the content C _{1 of the} metallic element is C
_The crystalline metallosilicate with ₁ > 450 ppm is subjected to at least one treatment of acid treatment, steam treatment or boiling water treatment so that the content C ₁ of the metal element is C ₁ ≦ 450.
It is characterized by adjusting to ppm.

[0008]

In the hydrogen type crystalline metallosilicate, when the content C ₁ of the metal element belonging to the alkali metal or the like is specified as described above, the destruction of the three-dimensional skeleton structure due to the metal element can be avoided. It is possible to greatly improve the heat resistance. However, the content rate C of the metal element
_{When 1} is C ₁ > 450 ppm, the heat resistance is low.

In the above production method, when acid treatment is applied, the alkali metal or the like of the crystalline metallosilicate is replaced with hydrogen ions, and when steam treatment or boiling water treatment is applied, the alkali metal or the like of the crystalline metallosilicate is changed. Hydrogen ions bond to the alkali metal leaving position generated by the reaction with water molecules that are active at high temperature.

Therefore, it is possible to easily obtain the above-mentioned hydrogen-type crystalline metallosilicate having heat resistance by applying acid treatment or the like alone or by combining them.

[0011]

EXAMPLES Hydrogen-type crystalline aluminosilicates as heat-resistant hydrogen-type crystalline metallosilicates include one or more metal elements selected from alkali metals, such as N.
a, K, or at least one metal element selected from alkaline earth metals, for example, at least one of Ca and Mg, the content C _{1 of which} is C ₁ ≦ 4
It is set to 50ppm.

Further, the hydrogen type crystalline aluminosilicate is
Fe, Cu, Ni or C that adversely affects the heat resistance
There is a case where an impurity that is at least one of r is contained, and in this case, the content ratio C _{2 of the} impurity is set to C ₂ ≦ 200 ppm in order to improve heat resistance.

In producing the heat-resistant hydrogen-type crystalline aluminosilicate, one or more metal elements selected from alkali metals, for example, one or more metals selected from Na, K, or alkaline earth metals. Element, eg C
a crystalline aluminosilicate containing at least one metal element of a and Mg and having a content C _{1 of the} metal element of C ₁ > 450 ppm is subjected to at least one treatment of acid treatment, steam treatment or boiling water treatment. Then, the content ratio C ₁ of the metal element is adjusted to C ₁ ≦ 450 ppm.

When the content C _{2 of the} impurities in the crystalline aluminosilicate is C ₂ > 200 ppm, the content C ₂ is C ₂ ≦ 200 by the above treatment.
Adjusted to ppm.

As the acid treatment, a method of raising the temperature of a 0.5 to 5 N HCl solution to 70 to 90 ° C. and immersing the crystalline aluminosilicate in the HCl solution for 5 to 20 hours is adopted.

As the boiling water treatment, the crystalline aluminosilicate is subjected to hydrous treatment, and the ambient temperature of the crystalline aluminosilicate in the hydrous state is 550 to 600 ° C.
The temperature is raised to the above temperature, and the crystalline aluminosilicate is kept under the high temperature atmosphere for about 4 hours.

Further, as the steam treatment, crystalline aluminosilicate is added to 750 to 9 containing about 10% of water.
A method of holding in an atmosphere of 00 ° C. for 10 to 20 hours is adopted.

These acid treatment, boiling water treatment and steam treatment are applied singly or in combination of two or more, and are repeated as necessary.

Next, a specific example will be described.

[Example-I] A crystalline aluminosilicate having a ZSM-5 type skeleton structure and an alkali metal N
a content C ₁ of C ₁ = 2685.3 ppm, impurity Fe
The content C ₂ of C ₂ = 1237 ppm was used.

First, the crystalline aluminosilicate was mixed with 90
Acid treatment in which it is immersed in a 1N HCl solution at 20 ° C. for 20 hours, and then the crystalline aluminosilicate after the acid treatment is
Steam treatment was carried out for 20 hours in an atmosphere of 900 ° C. containing 10% of water to obtain a hydrogen type crystalline aluminosilicate. This is referred to as Example 1.

Next, for Example 1, the Na content C₁, F
e Content C₂And SiO₂/ Al ₂O₃Molar ratio Mr
When examined, the Na content C₁= 0.1ppm, Fe content
Rate C ₂= 85ppm, SiO₂/ Al₂O₃Molar ratio Mr =
It turned out to be 57.

Thereafter, the heat resistant temperature of Example 1 was measured by the method described below. First, the BET specific surface area of Example 1, that is, the initial BET specific surface area was measured.
The sample was heated and heated in an air atmosphere containing 10% of water for 20 hours, and the BET specific surface area after heating was measured at every 25 ° C.
The temperature at which the BET specific surface area after heating maintained 95% of the initial BET specific surface area was taken as the heat resistant temperature of Example 1.

The heat-resistant temperature of Example 1 measured by such a method is 950 ° C., while the heat-resistant temperature of the crystalline aluminosilicate measured by the same method is 725 ° C., which is 225 ° C. in Example 1. An improvement of ℃ was recognized.

In the same manner as described above, a homogeneous crystalline aluminosilicate, that is, one having a ZSM-5 type skeleton structure and also containing an alkali metal Na and an impurity Fe is used, and SiO ₂ / Al ₂ O ₃ mol is used. Various hydrogen type crystalline aluminosilicates having a ratio Mr of Mr ≦ 100 were obtained.

Tables 1 and 2 show the Na content of the hydrogen-type crystalline aluminosilicates of Examples 1 (above) to 10, the Na content of the crystalline aluminosilicates used to obtain them, and the crystalline alumino. The processing method for silicates is shown. Table 2 also lists Examples 11 to 13 of crystalline aluminosilicates that are untreated.

In the table, in the column of treatment methods, the upper row shows the first treatment method and the lower row shows the second treatment method. In Tables 1 and 2, the upper part corresponds to acid treatment, and in Example 1, for example, “90 ° C., 1N HCl, 20 h” means “crystalline aluminosilicate at 90 ° C.” as described above.
In a 1N HCl solution for 20 hours ”. The lower part corresponds to steam treatment. For example, in Example 1, “10% H ₂ O, 900 ° C., 20 h” means that “crystalline aluminosilicate after acid treatment is 1
20 at 900 ℃ atmosphere containing 0% water (H ₂ O)
Hold for time '. Further SiO ₂ / Al
Column ₂ O ₃ molar ratio means SiO ₂ / Al ₂ O ₃ molar ratio of the hydrogen form crystalline aluminosilicate, but examples 11-13 are untreated product, its SiO ₂ / Al ₂ O ₃ molar ratio Is described in the column of SiO ₂ / Al ₂ O ₃ molar ratio.

[0028]

[Table 1]

[0029]

[Table 2]

FIG. 1 is a plot of the relationship between the Na content and the heat-resistant temperature of Examples 1 to 10 of hydrogen type crystalline aluminosilicate and Examples 11 to 13 of crystalline aluminosilicate based on Tables 1 and 2. Is. In the figure, points 1 to 13 correspond to Examples 1 to 13, and the relationship between the "point" and the "example" is the same in the subsequent drawings.

As is clear from FIG. 1, when the Na content C ₁ is set to C ₁ ≤450 ppm as in Examples 1 to 9 of hydrogen type crystalline aluminosilicate, the heat resistance temperature can be greatly improved. .

Table 3 shows SiO₂/ Al₂O₃Molar ratio Mr
Hydrogen-type crystalline aluminosilicates with Mr> 100
Used to obtain it, such as the Na content in Example 14 of
Na content of the obtained crystalline aluminosilicate and
The processing method for crystalline aluminosilicate is shown. Well
Table 3 shows the untreated crystalline aluminosilicate.
Examples 15 and 16 are also listed. In the table, the treatment method and
And SiO₂/ Al₂O ₃See table for interpretation of molar ratio column.
The same as 1 and 2.

[0033]

[Table 3]

FIG. 2 is a plot of the relationship between the Na content and the heat-resistant temperature of Example 14 of hydrogen-type crystalline aluminosilicate and Examples 15 and 16 of crystalline aluminosilicate based on Table 3. When the Na content C ₁ is set to C ₁ ≦ 450 ppm as in Example 14 of crystalline aluminosilicate, the heat resistance temperature can be significantly improved.

Table 4 has a mordenite type skeleton structure,
In addition, the Na content of Examples 17 to 22 of hydrogen-type crystalline aluminosilicates containing alkali metal Na and impurity Fe, the Na content of the crystalline aluminosilicate used to obtain them, and the treatment for the crystalline aluminosilicate Show the method. In addition, Table 4 also lists Examples 23 and 24 of crystalline aluminosilicates which are untreated. In the table, the treatment method and the interpretation of the column of SiO ₂ / Al ₂ O ₃ molar ratio are the same as those in Tables 1 and 2.

[0036]

[Table 4]

FIG. 3 is a plot of the relationship between the Na content and the heat-resistant temperature of Examples 17 to 22 of hydrogen type crystalline aluminosilicate and Examples 23 and 24 of crystalline aluminosilicate based on Table 4, As in Examples 17 to 21 of hydrogen type crystalline aluminosilicate, the Na content C _{1 is set} to C ₁ ≦
If it is set to 450ppm, the heat resistance temperature can be greatly improved.

Table 5 shows hydrogen-type crystalline aluminosilicates having a ZSM-5 type skeleton structure, Na or K as an alkali metal, Ca or Mg as an alkaline earth metal, and Fe as an impurity. Example 25-
The Na content of 28, the Na content of the crystalline aluminosilicate used to obtain them, and the treatment method for the crystalline aluminosilicate are shown.

In the table, in the column of processing method of Example 27,
“Hydrated state, 600 ° C., 4 h” means, in boiling water treatment, “atmospheric temperature of the crystalline aluminosilicate around the water state is raised to 600 ° C., and the crystalline aluminosilicate is kept under the high temperature atmosphere for 4 hours. Means "to do". Other treatment methods and SiO ₂ / Al ₂ O ₃
The interpretation of the molar ratio column is the same as in Tables 1 and 2.

[0040]

[Table 5]

As is clear from Table 5, the hydrogen-type crystalline aluminosilicates are Na and Ca, K and Ca,
Even if it contains alkali metals and alkaline earth metals such as Na and Mg, their total content C
_{When 1} is C ₁ ≦ 450 ppm, the heat resistance temperature can be significantly improved.

In Examples 29 to 38 of hydrogen type crystalline aluminosilicates having a ZSM-5 type skeleton structure and containing an alkali metal Na, Table 6 is a table in which the content C ₂ of the impurity Fe is considered. No. 7 is for considering the content C ₂ of the impurities Cu, Ni or Cr. Table 6,
7, the treatment method and the interpretation of the column of SiO ₂ / Al ₂ O ₃ molar ratio are the same as in Table 5.

[0043]

[Table 6]

[0044]

[Table 7]

FIG. 4 is a plot of the relationship between the Fe content and the like and the heat resistance temperature of Examples 29 to 38 of hydrogen type crystalline aluminosilicate based on Tables 6 and 7.
_{At 1} ≤ 450 ppm, the Fe content C _{2 is changed} to C ₂ ≤ 2 as in Examples 29 to 31 of hydrogen-type crystalline aluminosilicate.
Set to 00 ppm, or as in hydrogen crystalline aluminosilicate examples 35-37, Cu, Ni or Cr
When the content rate C ₂ is set to C ₂ ≦ 200 ppm, the heat resistance temperature can be significantly improved.

[0046]

According to the invention of claim _1, by specifying the content C ₁ of the alkali metal or the like as described above, a hydrogen type crystalline metallosilicate having excellent heat resistance can be provided. it can.

According to the invention of claim 3, the hydrogen type crystalline metallosilicate can be easily obtained.

[Brief description of drawings]

FIG. 1 is a graph of a first example showing the relationship between the Na content and the heat resistant temperature.

FIG. 2 is a graph of a second example showing the relationship between the Na content and the heat resistant temperature.

FIG. 3 is a graph of a third example showing the relationship between the Na content and the heat resistant temperature.

FIG. 4 is a graph showing the relationship between the Fe, Cu, Cr or Ni content and the heat resistant temperature.

Claims (3)

[Claims] 1. Containing at least one metal element selected from the group consisting of one or more metal elements selected from alkali metals and one or more metal elements selected from alkaline earth metals,
A hydrogen-type crystalline metallosilicate having heat resistance, characterized in that the content C ₁ of the metal element is set to C ₁ ≦ 450 ppm. 2. An impurity containing at least one of Fe, Cu, Ni and Cr, and a content ratio of the impurity C ₂
The heat-resistant hydrogen-type crystalline metallosilicate according to claim 1, wherein C ₂ ≦ 200 ppm. 3. Containing at least one metal element selected from the group consisting of one or more metal elements selected from alkali metals and one or more metal elements selected from alkaline earth metals,
Further, the crystalline metallosilicate having the content C ₁ of the metal element C ₁ > 450 ppm is subjected to at least one treatment of acid treatment, steam treatment or boiling water treatment to change the content C ₁ of the metal element to C ₁ A method for producing a hydrogen-type crystalline metallosilicate having heat resistance, which is characterized by adjusting to ≦ 450 ppm.