JP2501868B2 - Method for producing crystalline galloaluminosilicate and method for producing aromatic hydrocarbon - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing crystalline galloaluminosilicate and a method for producing aromatic hydrocarbons, and more specifically, to catalytic performance by calcination at high temperature for modification. The present invention relates to a method for efficiently producing a crystalline galloaluminosilicate having excellent properties, and a method for efficiently producing an aromatic hydrocarbon by using the crystalline galloaluminosilicate as a catalyst component.

[Problems to be Solved by Prior Art and Invention]

Conventionally, it has been known to use various zeolites as catalysts when producing aromatic hydrocarbons from various hydrocarbon raw materials. For example, when an aromatic hydrocarbon is produced from a hydrocarbon raw material having 2 to 12 carbon atoms, a method of using a crystalline galloaluminosilicate modified with steam as a catalyst (JP-A-60-501357), or carbon In producing an aromatic hydrocarbon from an aliphatic hydrocarbon mixture containing more than 50% of paraffins of the number 2 to 4, SiO ₂ / Ga ₂ O ₃ = 25 to 100 (molar ratio), Y ₂ O ₃ as a catalyst
/ Ga ₂ O ₃ <1 (molar ratio) (Y is Al, Fe, Co, Cr) using a crystalline siliceous gallium (Japanese Patent Laid-Open No. 59-98020), and further having 2 to 2 carbon atoms. SiO ₂ / Ga ₂ O ₃ = 25-250 (molar ratio) in producing an aromatic hydrocarbon from an aliphatic hydrocarbon mixture containing more than 50% of paraffin of 4
A crystalline siliceous gallium having Y ₂ O ₃ / Ga ₂ O ₃ <1 (molar ratio) (Y is Al, Fe, Co, Cr), to which 0.1 to 5% by weight of coke is deposited. One step or two or more steps of the second step of contacting with an oxygen-containing gas at a temperature of 350 to 700 ° C, or at a temperature of 600 to 1000 ° C before carrying out the two steps. For example, there is a method of using a material that has been calcined for 8 hours as a catalyst (JP-A-59-98022).

However, the method described in JP-A-60-501357 has problems that the yield of aromatic hydrocarbons is low and the catalyst life is short, and is disclosed in JP-A-59-98020. The method has the problem that it also has a short catalyst life. Further, the method described in JP-A-59-98022 requires a multi-step treatment when preparing the catalyst, which complicates the operation, and further, the yield of aromatic hydrocarbon is low, and the catalyst life is long. However, there is still a problem that it is not enough.

Therefore, the present invention solves the problems of the conventional methods and catalysts described above, and provides a method capable of producing aromatic hydrocarbons from various hydrocarbon raw materials in high yield over a long period of time, and a catalyst suitable for the method. We have earnestly studied for development.

[Means for solving the problem]

As a result, the crystalline galloaluminosilicate having a ZSM-5 type (MFI type) crystal structure was denatured by firing at high temperature, or was denatured by previously treating it with an aqueous alkali hydroxide solution and then denatured. It was found to be purposeful. The present invention has been completed based on such findings.

That is, the present invention provides ZSM-5 obtained by hydrothermal reaction.
700 ~ 100 galloaluminosilicate having a type crystal structure
The present invention provides a method for producing a modified crystalline galloaluminosilicate having a ZSM-5 type crystal structure (method I), which comprises firing at 0 ° C, and a ZSM-5 type crystal obtained by a hydrothermal reaction. The structured aluminoaluminosilicate is treated with an aqueous solution of alkali hydroxide, and then 70
Provided is a method for producing a modified crystalline galloaluminosilicate having a ZSM-5 type crystal structure (method II), which comprises firing at 0 to 1000 ° C. Furthermore, the present invention provides a catalyst containing a modified crystalline galloaluminosilicate obtained by the above method I or method II in producing an aromatic hydrocarbon by bringing a hydrocarbon having 2 to 12 carbon atoms into contact with the catalyst. It also provides a method for producing an aromatic hydrocarbon (method III), which is characterized by being used.

In the methods I and II of the present invention, there are various crystalline galloaluminosilicates having a ZSM-5 type crystal structure used as a raw material, but preferably SiO ₂ / Al when expressed in the form of an oxide. ₂ O ₃ ≧ 12 (molar ratio), Ga ₂
O ₃ / Al ₂ O ₃ = 0.0001 to 2 (molar ratio).
Here, the crystalline galloaluminosilicate as the above-mentioned raw material may or may not contain an organic compound. The organic compound contained in the crystalline galloaluminosilicate is usually the crystallization agent used in the production process of the crystalline galloaluminosilicate.

The crystalline galloaluminosilicate as a raw material for the methods I and II of the present invention is obtained by mixing an aqueous solution of each component source and an appropriate crystallization agent and conducting a hydrothermal reaction at a predetermined temperature and pressure. be able to.

Sources of each component used here include a silicon source (silica source), an aluminum source (alumina source), a gallium source and other metal sources (for example, an alkali metal source, an alkaline earth metal source, etc.).

Various materials can be used as the silicon source,
Examples thereof include silica powder, silicic acid, colloidal silica, and fused silica. Examples of the fused silica include water glass silicic acid and alkali metal silicate containing 1 to 5 mol of silicon oxide with respect to 1 mol of sodium oxide or potassium oxide. In addition, there are various aluminum sources, and examples thereof include aluminum sulfate, sodium aluminate, colloidal alumina, and alumina.

On the other hand, there are various gallium sources, and examples thereof include gallium nitrate and gallium oxide. Further, there are various alkali (earth) metal sources such as sodium chloride, potassium chloride, calcium chloride, magnesium chloride, etc. However, if the above-mentioned fused silica is used, it can also serve as a silicon source, and aluminum If sodium acid or the like is used, it can also serve as an aluminum source.

In addition, chlorides, oxides, hydroxides, carbonates, nitrates, sulfates and the like of rare earth metals and Group VIII metals of the Periodic Table can be added as necessary.

The crystallization agent used together with each of the component sources may be the crystallization agent conventionally used in the production of ZSM-5 type zeolite, and is not particularly limited.
That is, various organic compounds or ammonia is used. Here, as the organic compound, a quaternary alkylammonium salt (tetramethylammonium bromide, tetraethylammonium bromide, monoethyltrimethylammonium bromide, tetra-n-propylammonium bromide, toterra bromide) is used. i-propylammonium, tetrabutylammonium bromide, monobenzyltriethylammonium bromide, etc.), primary alkyl amines, secondary alkyl amines, tertiary alkyl amines, alcohol amines Examples include choline, alcohols, ethers and amides. Of these, quaternary alkyl ammonium salts are particularly preferable.

The above-mentioned component sources and the crystallization agent are added to water or an aqueous medium containing water as a main component to form an aqueous mixture, and the mixture is hydrothermally reacted to give a crystalline galloalumino having a ZSM-5 type crystal structure. Get a silicate. The conditions of the hydrothermal reaction at this time are not particularly limited, and in short, heating may be performed at a temperature, a pressure and a time necessary for producing a zeolite having a ZSM-5 type crystal structure. The reaction system may be usually left under stirring, and the atmosphere may be replaced with an inert gas if necessary. The pH is preferably adjusted to be neutral to alkaline.

The crystalline galloaluminosilicate having a ZSM-5 type crystal structure thus obtained contains an organic compound such as a crystallization agent used in the hydrothermal reaction.

According to the method I of the present invention, the crystalline galloaluminosilicate thus obtained as it is (that is, the state in which the organic compound is contained) or after the low temperature calcination in advance (that is, the state in which the organic compound disappears) ), 700 to 100
The target modified crystalline galloaluminosilicate is obtained by baking at 0 ° C., preferably 740 to 850 ° C. and modification. This modification is usually carried out in an atmosphere of dry air or an inert gas such as hydrogen gas or nitrogen gas, but it is most preferably carried out in dry air. When the heating temperature is less than 700 ° C, the modification is not sufficient, so when the obtained crystalline galloaluminosilicate is used as a catalyst for the reaction for producing aromatic hydrocarbons from various hydrocarbon raw materials, its catalytic performance and catalyst life are Is hardly improved compared to that before denaturation. Further, if the heating temperature exceeds 1000 ° C., the crystal structure will collapse and the catalytic activity will be lost.

Further, according to the method II of the present invention, a galloaluminosilicate having a ZSM-5 type crystal structure obtained by the aforementioned hydrothermal reaction, preferably a galloaluminosilicate having an ZSM-5 type crystal structure containing an organic compound, First, it is treated with an aqueous alkali hydroxide solution, and then, as it is, or after further low temperature calcination, the calcination treatment (modification treatment) at 700 to 1000 ° C. described above is performed. Here, the alkali hydroxide treatment uses an aqueous solution of potassium hydroxide, sodium hydroxide, calcium hydroxide, barium hydroxide, etc. having a concentration of 0.1 to 10N, preferably 0.5 to 2N, and a temperature of 0 to 100C. The galloaluminosilicate may be contact-treated for about 30 minutes to 3 days. By carrying out this alkali hydroxide treatment, it is possible to further improve the catalytic performance and life of the modified crystalline galloaluminosilicate finally obtained.

In the method II of the present invention, after carrying out the alkali hydroxide treatment, the treated galloaluminosilicate is treated in an amount of 700 to 100.
The composition is fired at a temperature of 0 ° C. to be modified, and the conditions for this firing are the same as in the case of the above-mentioned method I of the present invention.

The crystal structure of the modified crystalline galloaluminosilicate obtained by the methods I and II of the present invention is basically the same as that of the starting galloaluminosilicate, and ZSM-5
The crystal structure of the mold. Further, this crystalline galloaluminosilicate, when expressed in the form of an oxide, is SiO ₂ / Al ₂ O ₃ ≧ 12 (molar ratio), Ga ₂ O ₃ / Al ₂ O ₃ = 0.0001 to 2 (molar ratio). next, more specifically represented by the formula _{0.9 ± 0.2M 2 / n O ·} Al 2 O 3 · aGa 2 O 3 · bSiO 2 · zH 2 O. Where M is an alkali metal (sodium,
Potassium, etc.), alkaline earth metals (calcium, magnesium, barium, etc.), rare earth metals (lanthanum, cerium, etc.), Group VIII metals of the periodic table (platinum, iron, cobalt, nickel, etc.) or mixtures or hydrogen thereof. Indicates. Further, n is the valence of M described above. Furthermore, a
Is 0.0001 to 2, preferably 0.1 to 1.0, b is 12 or more, preferably 30 to 300, and z is 0 to 40.

Next, the method for producing an aromatic hydrocarbon of the present invention (Method II
In I), a catalyst containing the above modified crystalline galloaluminosilicate as a main component is used. Usually, this galloaluminosilicate contains clay, chemically treated clay, or a binder such as silica, silica / alumina, or an inorganic oxide such as alumina, in an amount of 1 to 95% by weight, preferably 10 to 70% by weight, of the galloaluminosilicate. What was mixed so as to be used as a catalyst.

There are various hydrocarbons having 2 to 12 carbon atoms used as a raw material in the method III of the present invention. For example, paraffinic hydrocarbons, olefinic hydrocarbons, acetylene hydrocarbons, cyclic paraffinic hydrocarbons, cyclic hydrocarbons. One or a mixture of two or more olefinic hydrocarbons,
Examples thereof include those containing a hydrocarbon having 2 to 12 carbon atoms as a main component, specifically, ethane, propane, butane-butylene fraction (BB fraction), ethylene, propylene or naphtha fraction.

In Method III of the present invention, the above hydrocarbon is used as a raw material and the above-described modified crystalline galloaluminosilicate is used as a catalyst, but other conditions are not particularly limited. However, generally, the reaction temperature is 200 to 800 ° C., preferably 400 to 650 ° C., and the reaction pressure is 0 to 30 kg / cm ² , preferably 0 to 10 kg / cm ² . The reaction system may be a batch system, but is preferably a continuous system (flow system), and the reaction system may be in a liquid phase, but is preferably in a gas phase. Furthermore, the catalyst reaction system may be in a fixed bed, moving bed, Either of the fluidized beds may be used. When the reaction system is a continuous system, the amount of the catalyst used is usually a weight hourly space velocity (WHSV) of 0.1 to 100 hr ^-1 , preferably 1
It is ~ 10hr ^-1 . Further, hydrogen gas or an inert gas (for example, nitrogen gas) can be introduced into the reaction system as a diluent.

〔Example〕

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Reference Example 1 (Preparation of crystalline galloaluminosilicate) A solution A was obtained by dissolving 7.6 g of aluminum sulfate, 6.9 g of gallium nitrate, 15.0 g of 97% concentration sulfuric acid and 26.4 g of tetrapropylammonium bromide in 250 ml of water. On the other hand, water glass (SiO ₂ :
214 g of 28.4% by weight, Na ₂ O: 9.5% by weight) was dissolved in 212 ml of water to obtain solution B, and 80 g of sodium chloride was dissolved in 122 ml of water to obtain solution C.

Next, the above liquids A and B were simultaneously dropped and mixed into the liquid C little by little using a dropping funnel. After the dropwise addition was completed, 5N sulfuric acid was added to adjust the pH to 9.5, and a hydrothermal reaction was carried out at 170 ° C for 20 hours under autogenous pressure (6.5 kg / cm ² G) in an autoclave. After cooling, the precipitate is separated and washed 5 times with water,
It was dried at 120 ° C. When the X-ray diffraction pattern of the obtained solid product was examined, it was confirmed to be the same as the X-ray diffraction pattern of ZSM-5 zeolite.

Subsequently, the solid product was calcined at 540 ° C. for 3 hours under air flow, ion-exchanged with a 1N ammonium nitrate solution at 80 ° C. for 2 hours, washed with water, and dried at 120 ° C. Thereafter, the firing, ion exchange, and drying were further repeated to obtain a crystalline galloaluminosilicate. When this crystalline galloaluminosilicate was analyzed, it was found that the component composition (oxide display) was SiO ₂ : Al ₂ O ₃ : Ga ₂ O ₃ = 80: 1: 0.7 (molar ratio).

Example 1 (1) Modification of crystalline galloaluminosilicate The crystalline galloaluminosilicate obtained in Reference Example 1 above was calcined at 700 ° C. for 3 hours under flowing dry air to obtain a modified crystalline galloaluminosilicate. Obtained.

(2) Production of Aromatic Hydrocarbon Using the modified crystalline galloaluminosilicate obtained in Example 1 (1) above as a catalyst and using light naphtha having the composition shown in Table 1 as a raw material, in an isothermal reactor. , Temperature 500 ℃, WH
The reaction was allowed to proceed under the conditions of SV (weight space velocity) 2.0 hr ⁻¹ and pressure of 1 atm. In this reaction, the time for which the yield of aromatic hydrocarbons can be maintained at 60% by weight or more was measured. The results are shown in Table 2.

Example 2 (1) Modification of crystalline galloaluminosilicate In the same manner as in Example 1 (1) except that the firing temperature was 740 ° C in Example 1 (1), modified crystals were obtained. A galloaluminosilicate having a high activity was obtained.

(2) Production of Aromatic Hydrocarbon Example 1 (2) except that the modified crystalline galloaluminosilicate obtained in Example 2 (1) above was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions as above, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 2.

Example 3 (1) Modification of crystalline galloaluminosilicate In the same manner as in Example 1 (1), except that the firing temperature was 780 ° C., modified crystals were obtained. A galloaluminosilicate having a high activity was obtained.

(2) Production of Aromatic Hydrocarbon Example 1 (2) except that the modified crystalline galloaluminosilicate obtained in Example 3 (1) above was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions as above, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 2.

Example 4 (1) Modification of crystalline galloaluminosilicate The modified crystal was prepared in the same manner as in Example 1 (1) except that the firing temperature was 820 ° C. A galloaluminosilicate having a high activity was obtained.

(2) Production of Aromatic Hydrocarbon Example 1 (2) except that the modified crystalline galloaluminosilicate obtained in Example 4 (1) above was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions as above, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 2.

Comparative Example 1 (1) Modification of crystalline galloaluminosilicate In Example 1 (1), the modified crystal was obtained by the same operation as in Example 1 (1) except that the firing temperature was 600 ° C. A galloaluminosilicate having a high activity was obtained.

(2) Production of aromatic hydrocarbon Example 1 (2) except that the modified crystalline galloaluminosilicate obtained in Comparative Example 1 (1) was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions as above, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 2.

Comparative Example 2 (1) Modification of crystalline galloaluminosilicate The modified crystal was prepared in the same manner as in Example 1 (1) except that the firing temperature was 660 ° C. A galloaluminosilicate having a high activity was obtained.

(2) Production of Aromatic Hydrocarbon Example 1 (2) except that the modified crystalline galloaluminosilicate obtained in Comparative Example 2 (1) was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions as above, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 2.

Comparative Example 3 (1) Modification of crystalline galloaluminosilicate The crystalline galloaluminosilicate obtained in Reference Example 1 above was calcined (steaming) with air containing 20% steam at 500 ° C for 1 hour, Then, it was further calcined at 540 ° C. for 3 hours under a flow of dry air to obtain a modified crystalline galloaluminosilicate.

(2) Production of Aromatic Hydrocarbon Example 1 (2) except that the modified crystalline galloaluminosilicate obtained in Comparative Example 3 (1) was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions as above, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 2.

Comparative Example 4 (1) Modification of crystalline galloaluminosilicate In Comparative Example 3 (1), the same operation as in Comparative Example 3 (1) was performed except that the steam treatment was performed for 2 hours.
A modified crystalline galloaluminosilicate was obtained.

(2) Production of Aromatic Hydrocarbon Example 1 (2) except that the modified crystalline galloaluminosilicate obtained in Comparative Example 4 (1) above was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions as above, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 2.

Comparative Example 5 (1) Modification of crystalline galloaluminosilicate In Comparative Example 3 (1), the same operation as in Comparative Example 3 (1) was performed except that the steam treatment was 3 hours.
A modified crystalline galloaluminosilicate was obtained.

(2) Production of Aromatic Hydrocarbon Example 1 (2) except that the modified crystalline galloaluminosilicate obtained in Comparative Example 5 (1) was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions as above, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 2.

Comparative Example 6 (1) Modification of crystalline galloaluminosilicate The modified crystalline galloaluminosilicate obtained in Comparative Example 3 (1) was treated with n-butane and a temperature of 600 at the first stage.
Approximately 1% by weight of coke is deposited on the galloaluminosilicate by contacting for 30 minutes under the conditions of ℃, pressure 1.5 bar, and WHSV8hr ^-1 , and then in the second stage, temperature is further increased to 500 ℃, pressure
The deposited coke was removed by contacting with dry air at 1.5 bar for 1 hour to obtain a modified crystalline galloaluminosilicate.

(2) Production of aromatic hydrocarbons Similar to Example 1 (2) except that the modified crystalline galloaluminosilicate obtained in Comparative Example 6 (1) was used as a catalyst in Example 1 (2). Perform the reaction under the conditions of
The time during which the yield of aromatic hydrocarbons can be maintained at 60% by weight or more was measured. As a result, the retention time was 28 hours, which was less than half the 57 hours of Example 3.

Reference Example 2 (Preparation of crystalline aluminosilicate) In Reference Example 1, aluminum sulfate 7.6 g, sulfuric acid 17.6 g
And tetrapropylammonium bromide 26.4g in water 250ml
A crystalline aluminosilicate was prepared in the same manner as in Reference Example 1 except that the solution A was dissolved in the above to obtain the solution A. X of this thing
When the line diffraction pattern was examined, it was confirmed to be the same as the X-ray diffraction pattern of ZSM-5 zeolite.
As a result of the analysis, the composition of components (indicated by oxide) is SiO ₂ :
Al ₂ O ₃ = 80: 1 (molar ratio).

Comparative Example 7 (1) Modification of crystalline aluminosilicate The crystalline aluminosilicate obtained in Reference Example 2 above was calcined at 600 ° C for 3 hours under flowing dry air to obtain a modified crystalline aluminosilicate. .

(2) Production of Aromatic Hydrocarbon As Example 1 (2), except that the modified crystalline aluminosilicate obtained in Comparative Example 7 (1) above was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions, and the yield of aromatic hydrocarbon one hour after the start of the reaction was measured and found to be 29% by weight.

Comparative Example 8 (1) Modification of Crystalline Aluminosilicate Comparative Example 7 (1) was carried out in the same manner as in Comparative Example 7 (1) except that the firing temperature was changed to 780 ° C. I got an aluminosilicate.

(2) Production of Aromatic Hydrocarbon As Example 1 (2), except that the modified crystalline aluminosilicate obtained in Comparative Example 8 (1) was used as a catalyst in Example 1 (2). The reaction was carried out under the same conditions, and the yield of aromatic hydrocarbon one hour after the reaction was started was 30% by weight.

From these results, it is found that ZSM-5 type zeolite (crystalline aluminosilicate) containing no gallium has almost no effect even if it is modified by heating at a high temperature.

Reference Example 3 (Preparation of crystalline galloaluminosilicate) A solution A was obtained by dissolving 7.6 g of aluminum sulfate, 6.9 g of gallium nitrate, 15.0 g of sulfuric acid at 97% concentration and 26.4 g of tetrapropylammonium bromide in 250 ml of water. On the other hand, water glass (SiO ₂ :
214 g of 28.4% by weight, Na ₂ O: 9.5% by weight) was dissolved in 212 ml of water to obtain solution B, and 80 g of sodium chloride was dissolved in 122 ml of water to obtain solution C.

Next, the above liquids A and B were simultaneously dropped and mixed into the liquid C little by little using a dropping funnel. After the completion of dropping, the pH was adjusted to 9.5 by adding 5N sulfuric acid, and the autoclave at 1 was operated under self-pressure (6.5kg / cm ² G) at 170 ° C for 20 hours at 300r.
Hydrothermal reaction was performed while stirring at pm. After cooling, the precipitate was separated, thoroughly washed with excess water, and dried at 120 ° C for 24 hours. When the X-ray diffraction pattern of the obtained solid product (crystalline galloaluminosilicate) was examined, it was confirmed to be the same as that of ZSM-5 zeolite.

Subsequently, this solid product was mixed with a 1N aqueous sodium hydroxide solution and treated in a water bath at 50 ° C. for 1 hour with stirring.

Subsequently, the solid product was calcined at 540 ° C. for 3 hours under air flow, ion-exchanged with a 1N ammonium nitrate solution at 80 ° C. for 2 hours, washed with water, and dried at 120 ° C. Then, the firing, ion exchange, and drying were further repeated to obtain an alkali-treated crystalline galloaluminosilicate. Analysis of the alkali-treated crystalline galloaluminosilicate revealed that the composition of the components (indicated by oxide) was SiO ₂ : Al ₂ O ₃ : Ga ₂
It was found that O ₃ = 80: 1: 0.7 (molar ratio).

Example 5 (1) Modification of Alkali-treated Crystalline Galloaluminosilicate The alkali-treated crystalline galloaluminosilicate obtained in Reference Example 3 above was modified by firing at 700 ° C. for 3 hours under a flow of dry air. A crystalline galloaluminosilicate was obtained.

(2) Production of aromatic hydrocarbon In the isothermal reactor using the modified crystalline galloaluminosilicate obtained in the above Example 5 (1) as a catalyst and the light naphtha having the composition shown in Table 1 as a raw material. Temperature 500 ℃, WHSV
The reaction was allowed to proceed under the conditions of 2.0 hr ⁻¹ and a pressure of 1 atm.

In this reaction, the yield of aromatic hydrocarbon is 60% by weight.
The time during which the above can be maintained was measured. The results are shown in Table 3.

Example 6 (1) Modification of alkali-treated crystalline galloaluminosilicate In Example 5 (1), the same operation as in Example 5 (1) was performed except that the firing temperature was 740 ° C. A modified crystalline galloaluminosilicate was obtained.

(2) Production of Aromatic Hydrocarbon In Example 5 (2), except that the modified crystalline galloaluminosilicate obtained in Example 6 (1) was used as a catalyst in Example 5 (2). The reaction was performed under the same conditions, and the time for which the yield of aromatic hydrocarbon was maintained at 60% by weight or more was measured. The results are shown in Table 3.

Example 7 (1) Modification of alkaline-treated crystalline galloaluminosilicate In Example 5 (1), the same operation as in Example 5 (1) was performed except that the firing temperature was 780 ° C. A modified crystalline galloaluminosilicate was obtained.

(2) Production of Aromatic Hydrocarbon In Example 5 (2), except that the modified crystalline galloaluminosilicate obtained in Example 7 (1) was used as a catalyst in Example 5 (2). The reaction was performed under the same conditions, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 3.

Example 8 (1) Modification of alkali-treated crystalline galloaluminosilicate In Example 5 (1), the same operation as in Example 5 (1) was performed except that the firing temperature was 820 ° C. A modified crystalline galloaluminosilicate was obtained.

(2) Production of Aromatic Hydrocarbon As in Example 5 (2), except that the modified crystalline galloaluminosilicate obtained in Example 8 (1) was used as a catalyst in Example 5 (2). The reaction was performed under the same conditions, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 3.

Comparative Example 9 (1) Modification of alkali-treated crystalline galloaluminosilicate In Example 5 (1), the same operation as in Example 5 (1) was performed except that the firing temperature was 600 ° C. A modified crystalline galloaluminosilicate was obtained.

(2) Production of Aromatic Hydrocarbon As Example 5 (2), except that the modified crystalline galloaluminosilicate obtained in Comparative Example 9 (1) was used as a catalyst in Example 5 (2). The reaction was performed under the same conditions, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 3.

Comparative Example 10 (1) Modification of alkali-treated crystalline galloaluminosilicate In Example 5 (1), the same operation as in Example 5 (1) was performed except that the firing temperature was 660 ° C. A modified crystalline galloaluminosilicate was obtained.

(2) Production of Aromatic Hydrocarbon As Example 5 (2), except that the modified crystalline galloaluminosilicate obtained in Comparative Example 10 (1) above was used as a catalyst in Example 5 (2). The reaction was performed under the same conditions, and the time for which the yield of aromatic hydrocarbons could be maintained at 60% by weight or more was measured. The results are shown in Table 3.

(Effects of the Invention) The modified crystalline galloaluminosilicate obtained by the methods I and II of the present invention has a long performance and long life as a catalyst as compared with conventional crystalline aluminosilicates and crystalline galloaluminosilicates. Since it can be obtained by a simple modification operation, it is expected to be effectively used not only as a catalyst for the production of aromatic hydrocarbons but also as a catalyst for other reactions or an adsorbent. Further, according to the method III of the present invention using the modified crystalline galloaluminosilicate as a catalyst, it is possible to produce an aromatic hydrocarbon from various hydrocarbons having 2 to 12 carbon atoms in a high yield over a long period of time. it can.

Therefore, the method III of the present invention can be effectively used for producing fuel oil or chemical products, particularly benzene, toluene and xylene.

Claims (3)

(57) [Claims] 1. A modified crystalline gallo having a ZSM-5 type crystal structure, characterized in that a galloaluminosilicate having a ZSM-5 type crystal structure obtained by a hydrothermal reaction is calcined at 700 to 1000 ° C. Method for producing aluminosilicate. 2. A ZSM-5 characterized in that a galloaluminosilicate having a ZSM-5 type crystal structure obtained by a hydrothermal reaction is treated with an aqueous solution of alkali hydroxide and then calcined at 700 to 1000 ° C. A method for producing a modified crystalline galloaluminosilicate having a crystalline structure. 3. When the aromatic hydrocarbon is produced by bringing a hydrocarbon having 2 to 12 carbon atoms into contact with a catalyst, it is preferable to use the catalyst containing the modified crystalline galloaluminosilicate according to claim 1 or 2. A method for producing an aromatic hydrocarbon, which is characterized.