JPS63277509A - Production of improved zsm-type zeolite - Google Patents

Abstract

PURPOSE:To efficiently obtain ZSM-type zeolite having improved catalyst life and performance, by treating an organic compound-containing ZSM-type zeolite prepared by hydrothermal reaction with an aqueous solution of an alkali hydroxide in a specific concentration or above. CONSTITUTION:Respective raw material components consisting of a silica source, alumina source, alkali (earth) metal source, etc., are mixed with a crystallizing agent consisting of a quaternary alkylammonium salt, etc. Water or an aqueous medium consisting of water is subsequently added to the resultant mixture to provide an aqueous mixture, which is hydrothermally reacted to afford zeolite having a ZSM-type crystal structure. The resultant ZSM-type zeolite containing NH3 as the crystallizing gent and organic compounds is then suitably dried, then treated with an aqueous solution of an alkali hydroxide in >=0.3 N concentration, washed with water, dried and fired to provide the desired ZSM-type zeolite having improved catalyst life. In this case, the crystallizing agent and other organic compounds are decomposed to disappear.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved method for producing ZSM type zeolite, and more specifically, by performing a strong alkali treatment during the zeolite preparation process, catalyst life and performance can be improved. The present invention relates to a method for efficiently producing an improved ZSM type zeolite.

[Problems to be solved by the prior art and the invention] In general, ZSM type zeolites are used in dewaxing reactions of lubricant base oils,
MTG reaction (reaction to produce gasoline from methanol)
It is also known as an effective catalyst in aromatization reactions of light hydrocarbon fractions.

However, although this ZSM type zeolite exhibits high catalytic performance in the above-mentioned reactions, it suffers from severe deterioration and short catalyst life.

Therefore, in recent years, in order to solve this problem, a method for producing fine zeolite (Japanese Patent Publication No. 61-2198) has been developed.
5 and JP-A No. 60-251121), the primary particles of zeolite produced by this method have a small diameter of about 0.02 to 0.05 μm;
This aggregates to form secondary particles with a diameter of 0.2 to 2.0 μm, and as a result, a sufficient effect of improving catalyst life cannot be achieved.

Furthermore, a method of redispersing the secondary particles by treating them with an alkali has been proposed (Japanese Unexamined Patent Publication No. 108316/1983), but even with this method, it is still not possible to sufficiently extend the catalyst life. I can't.

In view of the above circumstances, the present inventors have conducted extensive research in order to solve the problems of conventional ZSM type zeolites and to develop a method for efficiently producing improved ZSM type zeolites with a long catalyst life.

[Means for solving problems]

As a result, they discovered that the desired long-life ZSM zeolite could be obtained by treating the organic compound-containing ZSM zeolite produced in the ZSM zeolite manufacturing process with a strong alkaline aqueous solution of a certain concentration or higher. Ta.

The present invention was completed based on this knowledge. That is, the present invention provides an improved method for producing ZSM type zeolite, characterized in that ZSM type zeolite containing an organic compound obtained by a hydrothermal reaction is treated with an aqueous alkali hydroxide solution having a concentration of 0.3N' or more. A method for producing ZSM type zeolite is provided.

According to the present invention, first, each raw material component and a crystallizing agent are mixed, and the mixture is subjected to a hydrothermal reaction to produce ZSM type zeolite. The raw material components used here are silicon sources (
silica source), an aluminum source (alumina source), and an alkali metal source or alkaline earth metal source, and if necessary, there are other metal sources.

Various silicon sources can be used as the silicon source, such as silica powder, silicic acid, colloidal silica, and dissolved silica. This dissolved silica is
Examples include water glass silicates and alkali metal silicates containing 1 to 5 moles of silicon oxide per mole of sodium oxide or potassium oxide. There are various sources of aluminum, including aluminum sulfate and sodium aluminate.

Examples include colloidal alumina and alumina. Furthermore, there are various sources of alkaline earth metals, such as sodium chloride, potassium chloride, calcium chloride, and magnesium chloride, but if the above-mentioned dissolved silica is used, it can also serve as a silicon source, and sodium aluminate can also be used as a silicon source. If used, it can also serve as an aluminum source.

The ZSM type zeolite obtained by the method of the present invention contains 23
Not only M zeolite (aluminosilicate) itself, but also zeolites with the same crystal structure as 23M zeolite (for example, boroaluminosilicate, borosilicate, galloaluminosilicate, gallosilicate, ferroaluminosilicate, chromia aluminosilicate).

Chromia silicate, etc.) are also included. Therefore, this ZS
After firing, M-type zeolite basically consists of silica, alumina, and alkaline earth metal oxides, but it can also contain other metal oxides if necessary. Moreover, other metal oxides can be used instead of alumina. Other metal sources used at this time include:
Boron, phosphorus, titanium, vanadium, chromium, manganese, iron, zinc, gallium, germanium, arsenic.

Chlorides, oxides, and hydroxides of tin, antimony, etc.

Examples include carbonates, nitrates, and sulfates.

Further, the crystallizing agent used together with each raw material component is not particularly limited, and may be any crystallizing agent conventionally used in the production of 23M zeolite. That is, various organic compounds or ammonia are used. Here, the above-mentioned organic compounds include quaternary alkylammonium salts (tetramethylammonium bromide, tetraethylammonium bromide, monoethyltrimethylammonium bromide, tetra-n-propylammonium bromide, tetra-1-propylammonium bromide, bromide, tetrabutylammonium bromide, monobenzyltriethylammonium bromide, etc.), primary alkyl amines, secondary alkyl amines, tertiary alkyl amines, alcohol amines (choline, etc.).

Examples include alcohols, ethers, amides, etc. Among these, quaternary alkyl ammonium salts are particularly preferred.

In the method of the present invention, the above-mentioned raw material components and crystallizing agent are added to water or an aqueous medium containing water as a main component to form an aqueous mixture, and this is subjected to a hydrothermal reaction, thereby forming a crystal structure having a ZSM type crystal structure. Obtain zeolite. The conditions for the hydrothermal reaction at this time are not particularly limited, and in short, heating may be performed at a temperature, pressure, and time necessary to produce a zeolite having a ZSM type crystal structure. Further, the reaction system is usually kept under stirring, and the atmosphere may be replaced with an inert gas if necessary.

Note that the pH is preferably adjusted to be neutral to alkaline.

The ZSM type zeolite obtained by this hydrothermal reaction contains ammonia and an organic compound as a crystallizing agent. This ZSM type zeolite containing an organic compound (crystallizing agent) is optionally treated with an organic compound (such as ethanol, n-propylamide, tool.

i-propertool, n-butanol, i-butanol,
n-hexane, n-hebutane, benzene.

(This treatment is especially necessary when ammonia is used as a crystallizing agent.) After proper drying, this ZSM type zeolite is treated with an aqueous alkali hydroxide solution having a concentration of 0.3 normal or higher. Note that the alkali hydroxide aqueous solution treatment can be performed after the calcination treatment, but in that case, it is necessary to make the calcined ZSM type zeolite contain an organic compound such as the above-mentioned hydrocarbon.

'In the method of the present invention, it is necessary to perform the treatment with the aqueous alkali hydroxide solution on ZSM type zeolite containing organic compounds, and even if the treatment is performed on zeolite that does not contain organic compounds, The catalyst life of zeolites is hardly improved. Furthermore, depending on the situation, if a zeolite that does not contain an organic compound is treated with an alkali hydroxide aqueous solution, the ZSM type crystal structure may be destroyed. In this way, Z containing organic compounds
The reason why SM type zeolite is treated with an aqueous alkali hydroxide solution is not necessarily clear, but it may be caused by the crystallization agent contained in ZSM type zeolite or by the treatment after the hydrothermal reaction (or after the calcination treatment). It is presumed that the above-mentioned organic compounds such as hydrocarbons protect the ZSM type crystal structure against a highly concentrated aqueous alkali hydroxide solution.

The alkali hydroxide aqueous solution treatment in the method of the present invention needs to be carried out under a strong alkaline aqueous solution having a concentration of 0.3N or higher, preferably 0.5N or higher. Here, even if the treatment is performed with an aqueous alkali hydroxide solution having a concentration of less than 0.3N, the catalyst life of the ZSM type zeolite obtained will not be improved.

There are various types of alkali hydroxide used in this aqueous alkali hydroxide solution treatment, but sodium hydroxide or potassium hydroxide is generally preferred. Further, this alkaline hydroxide aqueous solution treatment proceeds under various conditions, but usually it may be carried out at a temperature of 20 to 100"C for a period of 30 minutes to 3 days.

In the method of the present invention, after performing such an aqueous alkali hydroxide treatment, washing with water, drying, and further calcination treatment are performed to obtain a ZSM type zeolite with an improved catalyst life as desired. The conditions for the calcination treatment at this time are not particularly limited and may be in accordance with known methods.In short, as a result of the calcination treatment, the crystallizing agent and other organic compounds in the ZSM type zeolite decompose and disappear, and the crystals forming It is sufficient that each component is in the form of a stable oxide.

〔Example〕

Next, the present invention will be explained in more detail based on Examples and Comparative Examples.

Example 1 (1) Production of ZSM type zeolite 7.6 g of aluminum sulfate, 9.2 g of gallium nitrate, 26.4 g of tetra-n-propylammonium bromide
Solution A was prepared by mixing 14.4 g of 97% sulfuric acid and 2501 ml of water. Also, water glass (Sing 28
．． Solution B was prepared by mixing 214 g (4% by weight, Nazo 0.95% by weight) and 212 cal of water, and solution C was prepared by further mixing 80 g of sodium chloride and 122 mj2 of water.

The above solutions A and B were mixed while being gradually added dropwise to solution C at the same time. Add sulfuric acid to the resulting mixture to adjust its pH.
After adjusting the temperature to 9.5, a hydrothermal reaction was carried out for 20 hours under autoclave at 170° C. and stirring at 300 rp+s in an autoclave.

After the reaction, the mixture was cooled, filtered, and thoroughly washed with excess pure water. Thereafter, it was dried at 120°C for a day and night to produce 5i-A/!, which has the same crystal structure as ZSM-5 zeolite. -Ga zeolite (galloaluminosilicate) was obtained.

Next, 5 g of this 5i-Al"Ga zeolite (which contains tetra-n-propylammonium bromide) was placed in 50 ta of potassium hydroxide aqueous solution with a concentration of 1, and heated at 50°C in a hot water bath. After that, it was filtered and thoroughly washed with pure water, dried at 120°C for a day and night, and then heated at 540°C in an air stream for 1 hour.
A firing process was performed for 3 hours.

After the calcination treatment, 8
Ion exchange, filtration, and water washing at 0°C for 2 hours.

The steps of drying at 120° C. and calcination at 540° C. in an air stream were repeated twice to obtain ZSM type zeolite (catalyst A). As a result of X-ray diffraction, the crystal structure of this catalyst A is 5i-Ajl! before alkali treatment (potassium hydroxide treatment)! −
It was confirmed that the crystal structure was the same as that of Ga zeolite (the same crystal structure as ZSM-5).

A scanning electron micrograph (SEM image) (magnification: 10,000 times) of catalyst A obtained by the above treatment is shown in FIG.

(2) Measurement of physical properties of ZSM type zeolite Next, the external surface area and 2,2-dimethylbutane (DMB) adsorption rate of this catalyst A were measured by the following method. The results are shown in Table 1.

External surface area: Measured by adsorbing and freezing benzene in the pores of a sample (catalyst A) in advance and examining the amount of nitrogen adsorbed on this sample (Journal of Catalysis
.

100.264 (1986)).

DMB adsorption rate: Using a pulse reactor, 0.7 μl of DMB was added to 100 μl of sample (catalyst A) under flowing hydrogen gas at 22 d/win.
It was measured by injecting.

(3) Measurement of catalyst life Using the above catalyst A, the temperature was 500°C and the pressure was normal pressure.

The aromatization reaction of n-hexane was carried out under the conditions of a weight hourly space velocity (WH3V) of 2 hr-', and the catalyst life was measured. The results are shown in Figure 4.

Example 2 (1) Production of ZSM type zeolite 5i-AI containing tetra-n-propylammonium bromide obtained in the middle of Example 1 (1).

The same operation as in Example 1 (1) was performed, except that the -Ga zeolite was stirred at 60° C. for 1 hour with an aqueous potassium hydroxide solution having a concentration of 1. ) As a result, ZSM
A type zeolite (catalyst B) was obtained, and this catalyst B was also found to have the same crystal structure as ZSM-5 by X-ray diffraction.

(2) Measurement of physical properties of ZSM type zeolite In Example 1 (2), the above (1) was used instead of catalyst A.
Example 1(2) except that catalyst B obtained in Example 1(2) was used.
The same operation as above was performed to measure the outer surface area and DMB adsorption rate of catalyst B. The results are shown in Table 1.

(3) Measuring catalyst life In Example 1 (3), the above (1) was used instead of catalyst A.
Example 1(3) except that catalyst B obtained in Example 1(3) was used.
The same operation as above was performed to measure the catalyst life. The results are shown in Figure 4.

Comparative Example 1 (1) Production of ZSM-type zeolite The same operations as in Example 1 (1) were carried out except that the treatment with 1N hydroxide and potassium aqueous solution was not performed in Example 1 (1). , a ZSM type zeolide (catalyst C) was obtained.

A scanning electron micrograph (SEM image) (magnification: 10,000 times) of catalyst C obtained by the above treatment is shown in FIG.

(2) Measurement of physical properties of ZSM type zeolite In Example 1 (2), the above (1) was used instead of catalyst A.
Example 1(2) except that catalyst C obtained in Example 1(2) was used.
The same operation as above was performed to measure the outer surface area and DMB adsorption rate of catalyst C. The results are shown in Table 1.

(3) Measuring catalyst life In Example 1 (3), the above (1) was used instead of catalyst A.
Example 1(3) except that catalyst C obtained in Example 1(3) was used.
The same operation as above was performed to measure the catalyst life. The results are shown in Figure 4.

Comparative Example 2 (1) Production of ZSM type zeolite Example 1 5i-A/! containing tetra-n-propylammonium bromide obtained in the middle of (1)! Example 1 except that -Ga zeolite was stirred in an aqueous potassium hydroxide solution with a concentration of 0.1N at 50°C for 1 hour.
The same operation as in (1) was performed to obtain ZSM type zeolite (catalyst D).

(2) Measurement of physical properties of ZSM type zeolite In Example 1 (2), the above (1) was used instead of the catalyst.
Example 1(2) except that the catalyst obtained in Example 1(2) was used.
The same operation as above was performed to measure the outer surface area of the catalyst and the DMB adsorption rate. The results are shown in Table 1.

Comparative Example 3 (1) Production of ZSM-type zeolite 5i-Af-Ga zeolite containing tetra-n-propylammonium bromide obtained in the middle of Example 1 (1) was added to an aqueous potassium hydroxide solution with a concentration of 0.1N. in,
Example 1 (except for stirring at 50°C for 8 hours)
Perform the same operation as in 1) to prepare ZSM type zeolite (catalyst E
) was obtained.

A scanning electron micrograph (SEM image) (magnification: 10,000 times) of catalyst E obtained by the above treatment is shown in FIG.

(2) Measurement of physical properties of ZSM type zeolite In Example 1 (2), the above (1) was used instead of catalyst A.
Example 1(2) except that catalyst E obtained in Example 1(2) was used.
The same operation as above was performed to measure the outer surface area and DMB adsorption rate of catalyst E. The results are shown in Table 1.

(3) Measuring catalyst life In Example 1 (3), the above (1) was used instead of catalyst A.
Example 1(3) except that catalyst E obtained in Example 1(3) was used.
The same operation as above was performed to measure the catalyst life. The results are shown in Figure 4.

Comparative Example 4 (1) Production of zeolite 5i-Affi-Ga containing tetra-n-propylammonium bromide obtained in the middle of Example 1 (1)
The zeolite was calcined in air at 540°C for 3 hours to remove tetra-n-propylammonium bromide, and then stirred in a 1N aqueous potassium hydroxide solution at 60°C for 1 hour. is Example 1 (1)
Zeolite (catalyst F) was obtained in the same manner as above.

(2) Measurement of physical properties of zeolite In Example 1 (2), the above (1) was used instead of catalyst A.
Example 1(2) except that catalyst F obtained in Example 1(2) was used.
The same operation as above was performed to measure the outer surface area and DMB adsorption rate of catalyst F. The results are shown in Table 1.

(3) Measurement of catalyst life In Example 1 (3), the above (1) was used instead of the catalyst.
Example 1(3) except that catalyst F obtained in Example 1(3) was used.
The same operation as above was performed to measure the catalyst life. The results are shown in Figure 4.

Comparing Figure 1 of Table 1 with Figure 2.3, it can be seen that by treatment with a strong alkaline aqueous solution, the secondary particles of zeolite were redispersed and became fine particles.

Further, as can be seen from Table 1, catalysts A and B have a large outer surface area and a large DMB adsorption rate, while catalyst F has a large outer surface area but a very small DMB adsorption rate. This is because in Catalyst F, ``i' S t Oz is eluted by strong alkali treatment, resulting in 5iOz/AfzOs (molar ratio) and 5iOz/AfzOs (molar ratio).
It is presumed that this is because the Oz/Ga2O3 (molar ratio) is smaller than that of other catalysts, and the crystal structure has changed to one other than the ZSM type.

Furthermore, as shown in Figure 4, the reactivity of catalysts A and B is high over a long period of time, while the reactivity of catalysts C, E, and F, especially catalyst F, is high over a long period of time.
It was found that the reactivity of the material decreased rapidly in a short period of time, and this life span was determined by the outer surface area in Table 1.

It shows a strong correlation with the DMB adsorption rate.

Therefore, it can be seen that the outer surface area and the DMB adsorption rate are effective indicators for evaluating the catalyst life.

Example 3 (1) Production of ZSM type zeolite In Example 1 (1), 7.6 g of aluminum sulfate,
Tetra-n-propylammonium bromide 26.4
Tetra-n having the same crystal structure as ZSM-5 zeolite was prepared in the same manner as in Example 1 (1) except that a mixture of 17.6 g of 97% sulfuric acid and 250 ++ 1 of water was prepared as Solution A.
-Propylammonium bromide-containing S i -A
Il zeolite (aluminosilicate) was obtained.

Next, 3 g of this S i -A 1 zeolite was added to a potassium hydroxide aqueous solution with a concentration of 0.5N (30+4!). The mixture was placed in a hot water bath and treated at 80° C. for 1 hour with stirring. Thereafter, ZSM type zeolite (catalyst G) was obtained in the same manner as in Example 1 (1).

(2) Measurement of physical properties of ZSM type zeolite In Example 1 (2), the above (1) was used instead of catalyst A.
Example 1(2) except that catalyst G obtained in Example 1(2) was used.
The same operation as above was performed to measure the outer surface area and DMB adsorption rate of catalyst G. The results are shown in Table 2.

Example 4 (1) Production of ZSM-type zeolite ZSM-type zeolite ( Catalyst H) was obtained.

(2) Measurement of physical properties of ZSM type zeolite In Example 1 (2), the above (1) was used instead of catalyst A.
Example 1(2) except that catalyst H obtained in Example 1(2) was used.
The same operation as above was performed to measure the outer surface area and DMB adsorption rate of catalyst H. The results are shown in Table 2.

Comparative Example 5 (1) Production of ZSM-type zeolite ZSM-type zeolite ( Catalyst I) was obtained.

(2) Measurement of physical properties of ZSM type zeolite In Example 1 (2), the above (1) was used instead of catalyst A.
Example 1(2) except that Catalyst I obtained in Example 1(2) was used.
The same operation as above was carried out to measure the outer surface area and DMB adsorption rate of catalyst (1). The results are shown in Table 2.

Comparative Example 6 (1) Production of ZSM-type zeolite ZSM-type zeolite ( Catalyst J) was obtained.

(2) Measurement of physical properties of ZSM type zeolite In Example 1 (2), the above (1) was used instead of catalyst A.
Example 1(2) except that catalyst J obtained in Example 1(2) was used.
The same operation as above was performed to measure the outer surface area and DMB adsorption rate of catalyst J. The results are shown in Table 2.

From the results shown in Table 2, it can be seen that using an alkaline aqueous solution with a concentration of O03 or higher is effective in obtaining a ZSM type zeolite with a long catalyst life.

〔Effect of the invention〕

As described above, according to the method of the present invention, fine-grained ZSM type zeolite (specifically, ZSM-5, ZSM-11,
ZSM-12, ZSM-23, ZSM-35, 25M-
38, 25M-48 or a zeolite with a crystal structure similar to these) is obtained, and this zeolite is produced by the dewaxing reaction of lubricant base oil.

It not only shows excellent catalytic performance in MTG reactions or aromatization reactions of light hydrocarbon fractions, but also has a significantly improved lifetime.

Therefore, the ZSM type zeolite obtained by the method of the present invention can be widely and effectively used in various reactions using zeolite catalysts.

[Brief explanation of drawings]

Figure 1 is a scanning electron micrograph (100x magnification) of the ZSM zeolite obtained in Example 1, and Figure 2 is a scanning electron micrograph (magnification 1x) of the ZSM zeolite obtained in Comparative Example 1. Figure 3 is a scanning electron micrograph (100x magnification) of the ZSM type zeolite obtained in Comparative Example 3, and Figure 4 is a photograph of the ZSM type zeolite obtained in Comparative Example 3. It is a graph showing the relationship between aromatic fraction yield and reaction time when zeolite is used. ← , 3-0. #a → Figure 2 1 Ichiginki → Figure 3 ← Yo67 Kai → Figure 4 Marumaru Time (Saibun) Procedural Dispute Official Book (Method) % Formula % 1. Case Indication Patent Application 1986-112479 2. Process for producing ZSM-type zeolite with improved name of the invention 3. Relationship with the amended person's case Patent applicant: Light Distillate New Application Development Technology Research Association 4, Agent address: 105 3-Toranomon, Minato-ku, Tokyo 25-36,
Column 7 for a brief explanation of the drawing to be corrected, page 24, line 19 to page 25, line 5 of the description of the contents of the amendment: ``Figure 1 shows a scanning electron microscope of the ZSM type zeolite obtained in Example 1. It is a photograph (10,000x magnification), and Figure 2 is Comparative Example 1.
FIG. 3 is a scanning electron micrograph (magnification: 10,000 times) of the ZSM type zeolite obtained in Comparative Example 3. "Figure 1 is a scanning electron micrograph (10,000x magnification) showing the crystal structure of the ZSM type zeolite obtained in Example 1, and Figure 2 is a scanning electron micrograph (magnification: 10,000 times) showing the structure of the ZSM type zeolite obtained in Comparative Example 1. FIG. 3 is a scanning electron micrograph (magnification: 10,000 times) showing the crystal structure of the ZSM type zeolite obtained in Comparative Example 3.
It is. ” is corrected. (that's all)

Claims (3)

[Claims] (1) An improved ZSM type zeolite characterized in that, in producing the ZSM type zeolite, an organic compound-containing ZSM type zeolite obtained by a hydrothermal reaction is treated with an aqueous alkali hydroxide solution having a concentration of 0.3N or more. manufacturing method. (2) Treatment with aqueous alkali hydroxide solution at a temperature of 20 to
The manufacturing method according to claim 1, which is carried out at 100°C. (3) The manufacturing method according to claim 1, wherein the aqueous alkali hydroxide solution is an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution.