JPS6234019B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to contacting xylenes containing ethylbenzene with a specific catalyst in the gas phase in the presence of hydrogen to isomerize the xylenes and convert ethylbenzene into other aromatic hydrocarbons. It is. Among the xylene mixtures, those currently of industrial importance are para-xylene and ortho-xylene. Paraxylene is used as a raw material for synthetic fiber polyester, and the demand for it has increased significantly. It is expected that this trend will continue in the future. Ortho-xylene is used as a crude raw material for phthalate ester, a plasticizer for polyvinyl chloride. However, the current demand for ortho-xylene is lower than that for para-xylene. On the other hand, meta-xylene currently has almost no industrial use. For this reason, it is industrially important to convert meta-xylene and ortho-xylene to para-xylene. Since the boiling points of xylene mixtures are close to each other, especially since the boiling points of para-xylene and meta-xylene are very close, it is economically disadvantageous to separate para-xylene by distillation. Therefore, industrial separation of paraxylene has been carried out by cryogenic separation that takes advantage of the difference in melting point.
In the case of cryogenic separation, there is a limit to the recovery rate of paraxylene per pass due to the eutectic point, which is at most (60%)/(1 pass). As a result, the concentration of paraxylene in the roughinate fluid after paraxylene recovery is quite high. On the other hand, recently, special public works were published in Showa 49-17246, 49-28181, 50-
An adsorption separation method has been developed as a new separation technique, as shown in Patent Nos. 10547, 50-11343, and 51-46093. In this adsorption separation method, it is theoretically possible to recover 100% of paraxylene per pass. That is, the concentration of paraxylene in the roughinate fluid after adsorption and separation is extremely low and theoretically becomes zero. Ortho-xylene has so far been generally separated by precision distillation methods. In this way, the remaining roughinate fluid from which para-xylene and ortho-xylene have been separated is sent to an isomerization step, where meta-xylene and/or ortho-xylene is isomerized to a para-xylene concentration close to the thermodynamic equilibrium composition, and then It is mixed with fresh feedstock and sent to a separation step, and the cycle is repeated. In such a combination process,
When the remaining roughinate fluid from which paraxylene has been separated by cryogenic separation is supplied to the isomerization process, as mentioned above, the concentration of paraxylene in the roughinate fluid is relatively high, but the paraxylene adsorption separation method In the case of the raffinate fluid after separation, the paraxylene concentration is extremely low. Therefore, the reaction in the isomerization step is required to be more severe in the latter case. In general, the xylene raw materials used industrially are reformed oil-based xylene obtained by reforming naphtha and subsequent aromatic extraction and fractional distillation, or cracked gasoline produced as a by-product from the thermal decomposition of naphtha. This is a cracked oil-based xylene obtained by aromatic extraction and fractional distillation. A particularly characteristic feature of cracked oil-based xylene is that the concentration of ethylbenzene is more than twice as high as that of reformed oil-based xylene. An example of its typical composition is shown in Table 1.

[Table] Generally, a considerable amount of ethylbenzene is present in a xylene mixture, but unless ethylbenzene is removed by some means, it will accumulate as it is recycled through the separation and isomerization steps. , an undesirable situation arises in which the concentration increases. For these reasons, it is currently preferable to use modified oil-based xylene with a low ethylbenzene concentration as a fresh feedstock, but in any case, it is necessary to reduce the ethylbenzene concentration, and several This method has been implemented industrially, and several other methods have been proposed. The methods can be broadly categorized into 1
One is to separate ethylbenzene as it is, and the other is to convert it into other useful compounds through reaction. Distillation is a method for separating ethylbenzene. In the case of this method, since the boiling point difference between xylenes and xylenes is small, it is necessary to use ultra-precision distillation, which requires a huge industrial investment in equipment and also has high operating costs, making it an economically disadvantageous method. . Furthermore, recently, as shown in JP-A-52-10223, there have been proposals to separate ethylbenzene by adsorption separation, but the separation performance thereof is not fully satisfactory. There are several other methods for removing ethylbenzene and converting it to other useful components. The most typical method is
46606, 49-47733, 51-15044, 51-36253, JP-A-54-16390, etc., this is a method of converting ethylbenzene into xylene.
However, in this method, it is essential that the catalyst contains platinum, which is an extremely expensive noble metal. Furthermore, in order to convert ethylbenzene into xylene, the reaction mechanism requires the intervention of non-aromatic components such as naphthene and paraffin, and their concentration in the product ranges from a few percent to several tens of percent. There is. Furthermore, since the conversion rate of ethylbenzene is controlled by thermodynamic equilibrium (Table 2), there are drawbacks such as limitations.

[Table] Furthermore, recently, a method for converting ethylbenzene into xylene using a mechanism different from the method using platinum has been disclosed in Japanese Patent Publication No. 41658/1983. In this method, ZSM-5 type, ZSM-12 type,
A catalyst containing ZSM-21 type zeolite is used, but this method has the disadvantage that xylene isomerization is slow. In particular, in order to isomerize a ruffinate fluid in which xylenes with a low para-xylene content, such as para-xylene, are adsorbed and separated, it is necessary to highly isomerize meta-xylene and even ortho-xylene to para-xylene. This is a fatal flaw in isomerizing xylenes with such a low para-xylene content. Furthermore, methods for converting ethylbenzene into components other than xylene have recently been proposed in Japanese Patent Publication Nos. 41657-1987 and 148028-1983. This method attempts to isomerize xylene and at the same time convert ethylbenzene into benzene and diethylbenzene through a disproportionation reaction, and separate the benzene and diethylbenzene by taking advantage of the large boiling point difference between them. Benzene obtained in this way is in great demand as a raw material for synthetic fiber nylon, but there is little demand for diethylbenzene, which is economically disadvantageous since it needs to be converted into other useful compounds. The present inventors have conducted intensive studies on catalysts that can deethylate ethylbenzene to benzene and at the same time can highly isomerize xylene. As a result, a catalyst containing crystalline aluminosilicate and mordenite-type zeolite obtained by reacting an aqueous reaction mixture consisting of a silica source, an alumina source, an alkali source, and an aliphatic carboxylic acid or its salt contains ethylbenzene in the presence of hydrogen. It has been discovered that this reaction proceeds efficiently by bringing xylenes into contact with each other, and the present invention has been achieved. The crystalline aluminosilicate used in the present invention can be synthesized as follows. An aqueous reaction mixture consisting of a silica source, an alumina source, an alkali source, and an aliphatic carboxylic acid or its derivative (indicated by SiO ₂ , Al ₂ O ₃ , OH ^- and A, respectively) is expressed as a molar ratio and has the following composition range (more preferable Range) _SiO2 / _{Al2O3 5} ~500 10~200 _H2O / _SiO2 5~100 10~50 ^OH- / _SiO2 0.01~1.0 0.02~0.8 A/ _{Al2O3 0.1} ~200 0.5~100 It can be produced by preparing it so that it enters the crystals and reacting it until crystals form. As the silica source, for example, silica sol, silica gel, silica airgel, silica hydrogel, silicic acid, silicate ester, sodium silicate, etc. are used. Alumina sources include sodium aluminate, aluminum sulfate, aluminum nitrate, alumina sol,
Alumina gel, activated alumina, gamma alumina, alpha alumina, etc. are used. Caustic soda, caustic potash, etc. are used as the alkali source, and caustic soda is preferred. These alkaline sources are added so that OH ^- is present in the system preferably in the above composition. The aliphatic carboxylic acid or its derivative has 1 to 12 carbon atoms, preferably 3 to 6 carbon atoms,
Specifically, monobasic oxycarboxylic acids such as glycolic acid, lactic acid, hydroacrylic acid, oxybutyric acid and their derivatives, dibasic and polybasic oxycarboxylic acids such as tartronic acid, malic acid, tartaric acid, citric acid and their derivatives. derivatives, monobasic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, acrylic acid, crotonic acid, methacrylic acid or derivatives thereof, dibasic and polybasic carboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid Acid, adipic acid, maleic acid, fumaric acid or derivatives thereof are used. Examples of the derivatives include water-soluble derivatives such as salts thereof. These aliphatic carboxylic acids or derivatives thereof may be used alone or in combination of two or more. The aqueous reaction mixture thus prepared is made into a slurry as uniform as possible and crystallized in a closed container, such as an autoclave made of iron, stainless steel, or lined with Teflon. The reaction conditions for crystallization are a reaction temperature of 80~
The reaction temperature is 250°C, preferably 100 to 200°C, and the reaction temperature is 5 hours to 30 days, preferably 10 hours to 10 days. The reaction mixture is preferably kept in a homogeneous state by stirring continuously or periodically during crystallization. After cooling, the crystallized reaction product was taken out from the closed container, washed with water, passed through the mouth,
Dry as necessary. Typical X-ray diffraction patterns of the crystalline aluminosilicate thus synthesized are shown in Table 3. Measurement of the X-ray diffraction pattern was carried out according to a conventional method. That is, X-ray irradiation is performed using copper K-α rays using a Geiger counter spectrometer equipped with a recording device to obtain a diffraction pattern. From this diffraction pattern, the relative intensity 100I/I _p (I _p is the strongest line) and the lattice spacing d (unit: angstrom Å) are determined. Table 3 X-ray diffraction pattern dÅ 100I/I _p 11.2±0.2 VS 10.2±0.2 S 9.8±0.2 M 6.37±0.1 W 6.00±0.1 W 5.71±0.1 W 5.58±0.1 W 4.37±0.08 W 4.27±0.08 W 3.86 ±0.08 VS 8.32±0.08 VS 3.75±0.08 S 3.72±0.08 S 3.66±0.05 M 3.00±0.05 M 2.00±0.05 W However, the relative strength (100I/I _p ) is as follows: VS = very strong, S = strong, M = intermediate The strength is expressed as W=weak. The crystalline aluminosilicate synthesized in this way does not have solid acidity as it is. When used in the conversion reaction of aromatic hydrocarbons, it is necessary to impart solid acidity to crystalline aluminosilicate to make it into an acid form. As is well known, acid type crystalline aluminosilicate has a polyvalent cation of divalent or higher valence such as hydrogen ion, ammonium ion, or rare earth ion as a cation in crystalline aluminosilicate.
These are usually crystalline aluminosilicate containing monovalent alkali metal ions such as sodium, and at least a portion of the alkali metal ions are replaced with hydrogen ions,
Obtained by ion exchange with ammonium cations or polyvalent cations. Such ion exchange treatments are often referred to as dealkalization treatments. In the present invention, ion exchange treatment is preferred in which hydrogen ions and/or hydrogen ion precursors are introduced into the crystalline aluminosilicate by treatment with a solution containing an acid and/or an ammonium salt compound. Ion exchange treatment is generally performed in an aqueous solution. Inorganic acids or organic acids can be used, with inorganic acids being more common. Examples of the inorganic acid include hydrochloric acid, nitric acid, phosphoric acid, carbonic acid, etc., but of course other acids may be used as long as they contain hydrogen ions. When using inorganic acids,
Treatment with a solution of too high a concentration is undesirable because the crystal structure will be destroyed. Since the concentration of the acid preferably used varies greatly depending on the type of acid, it is difficult to determine it unambiguously, and when using it, sufficient care must be taken to avoid destruction of the crystal structure. As ammonium salt compounds, inorganic ammonium salts such as ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium carbonate, aqueous ammonia, etc., or ammonium salts of organic acids such as ammonium formate, ammonium acetate, ammonium citrate, etc. can be used, but more Inorganic ammonium salts are preferred. The concentration of the ammonium salt used is preferably a solution of 0.05 to 4N, more preferably about 0.1N.
There are two provisions. As a method for ion exchange treatment of crystalline aluminosilicate with an acid and/or ammonium salt solution, either a batch method or a flow method is preferably used. When processing in batches, the solid-liquid ratio should be at least the amount that allows the crystalline aluminosilicate to come into sufficient contact with the liquid, and approximately 1/2.
Kg or more is preferable. A treatment time of about 0.1 to 72 hours is sufficient, preferably about 0.5 to 24 hours. The treatment temperature may be below the boiling point, but it is preferable to heat it to promote the ion exchange rate. In the case of flow treatment, a fixed bed method, a fluidized bed method, etc. can be used, but it is necessary to take measures to prevent uneven flow of the fluid or non-uniform ion exchange treatment. The ion exchange treated crystalline aluminosilicate is then washed with water. Distilled water is preferably used as the washing liquid, and the washing may be carried out in batches or in a flow manner. In this way, hydrogen ions and/or ammonium ions, which are hydrogen ion precursors, are introduced into the crystalline aluminosilicate to impart solid acidity. Hydrogen ions and/or cations other than their precursors may be present in the crystalline aluminosilicate, and the type and amount thereof are not particularly limited. The apparatus that can be used for the reaction according to the present invention may be either a fixed bed or a fluidized bed, but a fixed bed type is preferably used because the apparatus is simpler and the operation is easier. In the case of a fixed bed system, the smaller the catalyst particle size, the better from the point of view of catalyst effectiveness coefficient.
If the particle size becomes too small, pressure loss will conversely increase, which is not preferable. Therefore, there is a preferable range for the catalyst particle size. The preferred particle size is
0.05 to 10 mm, more preferably 0.1 to 2 mm
It is. The synthesized crystalline aluminosilicate is usually in a powder state. Therefore, in order to obtain a catalyst having such a preferable range, it is necessary to mold the catalyst. Examples of the molding method include compression molding and extrusion molding. Particularly in the case of extrusion molding, it is preferable to use a binder in order to improve the moldability or to impart strength to the molded product. Of course, it goes without saying that there is no need to use a binder if it can be sufficiently molded without a binder. Examples of binders include natural clays such as kaolin, bentonite, and montmorillonite, or silica gel;
Examples include synthetic products such as alumina sol and alumina gel. The amount of binder added is 70% by weight or less, preferably 20% by weight or less. Such molding may be performed before ion exchange treatment of the crystalline aluminosilicate, or ion exchange may be performed after molding. In the conversion of xylenes containing ethylbenzene according to the present invention, mordenite-type zeolite is further included as a catalyst component. The mordenite type zeolite that can be used may be either a synthetic product or a natural product, and of course, a mixture thereof may be used. When used as a catalyst component, it is necessary to impart solid acidity. To impart solid acidity,
As mentioned above, this is achieved by ion exchange treatment with a solution containing an acid and/or an ammonium salt compound. The mordenite-type zeolite only needs to have solid acidity, but it is particularly preferable that hydrogen ions and/or their precursors are present in an amount of 0.2 to 0.5 equivalent per aluminum atom constituting the mordenite-type zeolite. In other words, the dealkalization rate is 20
~50% is preferred. It is preferable that alkaline earth metal ions and/or copper group element ions such as copper and silver are present as other residual cations, but of course other types of cations may be used. The preferred amount of mordenite-type zeolite to be added to the entire catalyst depends on the degree of solid acidity, but it ranges over a fairly wide range, usually 99.9% by weight or less,
Preferably it is 5.0 to 99.5% by weight, more preferably 10.0 to 99.0% by weight. In order to further improve the selectivity of the reaction according to the present invention, it is preferable to add components such as phosphorus, rhenium, molybdenum, vanadium, and tungsten to the catalyst alone or in combination. Particularly preferred is the addition of rhenium. Methods for adding phosphorus, rhenium, molybdenum, vanadium, and tungsten include kneading, impregnation, and physical mixing of powders, but are not necessarily limited to these methods. However, from the standpoint of the catalyst, the more uniformly these components are dispersed, the better the activity and selectivity will be, so a kneading method or an impregnation method that provides good dispersibility is preferred. Phosphorus that can be used is phosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, tertiary ammonium phosphate, aluminum dihydrogen phosphate, aluminum phosphate, ammonium phosphomolybdate, ammonium phosphotungstate, phosphoric acid Examples include copper. The amount of phosphorus added in elemental form is 20% by weight or less, preferably 10% by weight or less, based on the total weight of the catalyst. Rhenium oxide can be used as rhenium.
Examples include perrhenic acid, ammonium perrhenate, and rhenium sulfide. The amount of rhenium that can be expected to be effective is based on the weight of the entire catalyst.
It is 0.005% by weight or more in elemental form. However, if the amount added is too large, side reactions will occur during the hydrogenolysis reaction, so it is necessary to limit the amount to 3% by weight or less, preferably 0.5% by weight or less. Examples of molybdenum that can be used include ammonium molybdate, ammonium phosphomolybdate, molybdic acid, molybdenum oxide, molybdenum sulfide, and molybdate salts. Examples of vanadium that can be used include ammonium metavanadate, vanadium oxynitrate, vanadium oxysulfate, vanadium oxyoxalate, vanadium oxydichloride, vanadium oxide, and vanadate. Examples of tungsten that can be used include ammonium tungstate, ammonium phosphotungstate, tungsten oxide, tungsten sulfide, tungsten carbide, and tungstate salts. The amount of molybdenum, tungsten or vanadium added in elemental form is 10% by weight or less, preferably 5% by weight. The catalyst prepared as described above is dried prior to use and subsequently calcined. Drying is carried out at 50 to 250°C for 0.1 hour or more, preferably 0.5 to 48 hours. Firing is
0.1 hour or more at 300-700℃, preferably 400-600℃
It is carried out for 0.5-24 hours at °C. In addition, through such calcination, the ammonium ions introduced in the ion exchange treatment are converted into hydrogen ions, and furthermore, as the calcination temperature is increased, the hydrogen ions are converted into a decationized form. Of course, catalysts in such a form can also be used satisfactorily. The catalyst prepared as described above is used under the following reaction conditions. That is, the reaction operation temperature is 300-600°C, preferably 350-550°C. Reaction operating pressure ranges from atmospheric pressure to 100Kg/cm ² G,
Preferably, the pressure is from atmospheric pressure to 50 kg/cm ² G. Time factor W/F meaning contact time of reaction
(g-at.W/g-mol co-feeding raw material) (W: catalyst weight,
F: moles of feedstock per hour) is from 0.1 to 200, preferably from 1 to 100. Hydrogen in the reaction system is essential. If the hydrogen concentration is too low, the dealkylation reaction of ethylbenzene will not proceed sufficiently, and furthermore, the deposition of carbonaceous components on the catalyst will cause the activity to deteriorate over time. On the other hand, excessively high hydrogen concentration increases the hydrogenolysis reaction, which is not preferable. Therefore, there is a preferable range for hydrogen concentration.
The hydrogen concentration is 1 to 50, preferably 3 to 50, expressed as the molar ratio (H ₂ /F) between hydrogen and feedstock in the reaction system.
It is 30. A xylene mixture containing ethylbenzene is used as the feedstock, but there is no particular restriction on the concentration of ethylbenzene in the xylene mixture. The concentration of paraxylene in the xylene mixture used is below the thermodynamic equilibrium concentration, but even if the xylene mixture contains paraxylene at the thermodynamic equilibrium concentration, it can also be used as a feedstock for the purpose of reducing the ethylbenzene concentration. Of course, this is possible as one form of usage. The feedstock may contain other aromatic components such as benzene, toluene, trimethylbenzene, ethyltoluene, diethylbenzene,
Even if ethylxylene or the like is contained, there is no problem as long as the concentration is within a low range. Hereinafter, the present invention will be explained using examples. Synthesis example 1 Solid caustic soda (NaOH97.0% by weight, H ₂ O3.0
Weight%) 14.7 g, tartaric acid 10.5 g water 350.7
Dissolved in grams. Add sodium aluminate (Al ₂ O ₃ 19.5% by weight, NaOH 26.1% by weight, H ₂ O 54.4% by weight) to this solution.
% by weight) was added to make a homogeneous solution.
66.0 grams of silicic acid (SiO ₂ 90.9% by weight, H ₂ O 10.1% by weight) powder commercially available as White Carbon was gradually added to this mixture while stirring.
A homogeneous slurry aqueous reaction mixture was prepared. The composition ratio (molar ratio) of this reaction mixture was as follows. SiO ₂ /Al ₂ O ₃ 100 H ₂ O/SiO ₂ 20 OH ⁻ /SiO ₂ 0.24 A/Al ₂ O ₃ 7 This mixture was placed in a 500 ml autoclave and sealed. Thereafter, the mixture was heated to 160° C. with stirring and crystallized for 72 hours. After crystallization, cool
The product is then removed from the autoclave and
Rinse with distilled water until pH is almost neutral, sip through mouth,
It was dried at 110°C overnight. The resulting product was a zeolite having the X-ray diffraction pattern shown in Table 3. Synthesis Example 2 9.22 grams of solid caustic soda and 12.5 grams of tartaric acid were dissolved in 344.2 grams of water. 17.5 grams of sodium aluminate was added to this solution to make a homogeneous solution. 66.0 grams of silicic acid was gradually added to this mixture with stirring to prepare a homogeneous slurry-like aqueous reaction mixture. Composition ratio (molar ratio) of this reaction mixture
was as follows. SiO ₂ /Al ₂ O ₃ 30 H ₂ O/SiO ₂ 20 OH ⁻ /SiO ₂ 0.171 A/Al ₂ O ₃ 2.5 This mixture was placed in a 500 ml autoclave and sealed. Thereafter, the mixture was heated to 160° C. with stirring and crystallized for 72 hours. After crystallization, cool
The product is then removed from the autoclave and
Rinse with distilled water until pH is almost neutral, sip through mouth,
It was dried at 110°C overnight. The resulting product was a zeolite having the X-ray diffraction pattern shown in Table 3. Comparative example The zeolite powder synthesized in Synthesis Example 1 was mixed with a 0.187 normal ammonium chloride aqueous solution at a solid-liquid ratio of 5 (/
Kg), heated to 80 to 90°C, and subjected to ion exchange treatment in batches for 30 minutes. Thereafter, it was thoroughly washed with distilled water and dried at 110°C overnight. To this dealkalized zeolite powder, alumina sol was added as a binder in an amount of 15% by weight in terms of alumina (Al ₂ O ₃ ), and thoroughly kneaded. 10 to 24 mesh after kneading (JIS
The particles were molded into particles the size of a sieve, dried at 110°C overnight, and then calcined at 500°C for 2 hours in the presence of air. This catalyst is abbreviated as "A". Table 4 shows the results of evaluating the catalytic activity using a feedstock consisting of ethylbenzene and xylene. Example 1 Synthetic sodium mordenite “Zeolon 100-NA” powder manufactured by Norton was heated at 80 to 90°C with a 0.169 normal calcium nitrate aqueous solution at a solid-liquid ratio of 5 (/Kg).
The sample was heated to 100 mL and subjected to ion exchange treatment in batches for 30 minutes. Thereafter, it was washed once with distilled water and subjected to calcium ion exchange treatment again, and this operation was repeated five times. After that, wash thoroughly with distilled water and heat at 110℃ for 1 hour.
Dry overnight. Next, this calcium-type mordenite powder was heated to 80 to 90°C with a 0.187 normal ammonium chloride aqueous solution at a solid-liquid ratio of 5 (/Kg), and
The dealkalization treatment was carried out in batches for 1 minute. Thereafter, it was thoroughly washed with distilled water and dried at 110°C overnight. The dealkalization rate of this dealkalized calcium-type mordenite was 32.1%. The zeolite powder synthesized in Synthesis Example 1 was subjected to dealkalization treatment in the same manner as in Comparative Example. This zeolite powder and calcium-type dealkalized mordenite powder were mixed at a weight ratio of 1:1. To this mixture was added 15% by weight of alumina sol as a binder in terms of alumina (Al ₂ O ₃ ), and the mixture was sufficiently kneaded. After kneading, the particles were formed into particles having a size of 10 to 24 meshes (JIS sieve), dried at 110°C overnight, and then calcined at 500°C for 2 hours in the presence of air. This catalyst is abbreviated as "B". Table 4 shows the results of evaluating the catalytic activity. As shown in Table 4, when using the catalyst mixed with mordenite (this example) compared to the zeolite synthesized in Synthesis Example 1 alone (comparative example), the amount of conversion from meta-xylene to para-xylene was larger, and The amount of paraxylene also increases. Example 2 To zeolite powder mixed in the same manner as in Example 1, 0.1% by weight of perrhenic acid aqueous solution was added in terms of rhenium element, and to this was added 15% by weight in terms of alumina (Al ₂ O ₃ ) using alumina sol as a binder. The mixture was added and thoroughly kneaded. Drying was carried out at 110°C for one night, and then calcined in air at 500°C for 2 hours. This catalyst is abbreviated as "C". Catalytic activity is shown in Table 4. It can be seen that by adding rhenium, by-products such as diethylbenzene and ethylxylene are reduced, and the xylene recovery rate is greatly improved. Example 3 The zeolite powder synthesized in Synthesis Example 2 was mixed with a 0.374 normal ammonium chloride aqueous solution at a solid-liquid ratio of 5 (/
Kg), heated to 80 to 90°C, and subjected to ion exchange treatment for 30 minutes. Thereafter, it was thoroughly washed with distilled water and dried at 110°C overnight. This dealkalized zeolite powder and calcium-type mordenite powder dealkalized in the same manner as in Example 1 were mixed at a weight ratio of 1:50. To this mixture, 15% by weight of alumina sol was added as a binder in terms of alumina (Al ₂ O ₃ ), and a perrhenic acid aqueous solution was added to it in terms of rhenium.
0.1% by weight was added and thoroughly kneaded. After kneading, 10-24
The particles were formed into mesh-sized particles, dried at 110°C overnight, and then calcined at 500°C for 2 hours in the presence of air. This catalyst is abbreviated as "D". Catalytic activity is shown in Table 4. Synthesis Example 3 21.0 grams of solid caustic soda and 19.6 grams of citric acid were dissolved in 374.3 grams of water. 4.45 grams of sodium aluminate solution was added to this solution to make a homogeneous solution. 56.1 grams of silicic acid was gradually added to this mixture with stirring to prepare a homogeneous slurry aqueous reaction mixture. The composition ratio (molar ratio) of this reaction mixture was as follows. SiO ₂ /Al ₂ O ₃ 100 H ₂ O/SiO ₂ 25 OH ⁻ /SiO ₂ 0.30 A/Al ₂ O ₃ 11 This mixture was placed in a 500 ml autoclave and sealed. Thereafter, the mixture was heated to 160° C. with stirring and crystallized for 72 hours. After the crystallization was completed, the product was cooled, taken out from the autoclave, washed with distilled water until the pH became almost neutral, passed through the mouth, and dried overnight to obtain zeolite. Example 4 Natural mordenite from Miyagi Prefecture was crushed and further crushed into a powder of 200 mesh or less. this
0.187 Normal ammonium chloride aqueous solution with solid-liquid ratio of 5
(/Kg), heated to 80 to 90°C, and dealkalized in batches for 30 minutes. Thereafter, it was thoroughly washed with distilled water and dried at 110°C overnight. The zeolite powder synthesized in Synthesis Example 3 was subjected to dealkalization treatment in the same manner as in Comparative Example. This zeolite powder and dealkalized natural mordenite powder were mixed at a weight ratio of 1:4. To this mixture, 3% by weight of alumina sol was added as a binder in terms of alumina (Al ₂ O ₃ ),
Add perrhenic acid aqueous solution to it in terms of rhenium: 0.1
% by weight was added and thoroughly kneaded. After kneading, the particles were formed into particles having a size of 10 to 24 meshes, dried at 110°C overnight, and then calcined at 500°C for 2 hours in the presence of air. This catalyst is abbreviated as "E". Catalytic activity is shown in Table 4.

【table】

【table】

Claims (1)

[Claims] 1. Silica source, alumina source, alkali source, and aliphatic carboxylic acid or its derivative expressed in molar ratio: SiO ₂ /Al ₂ O ₃ 5-500 H ₂ O/SiO ₂ 5-100 OH ^- Crystalline aluminosilicate and mordenite-type zeolite obtained by reacting an aqueous reaction mixture with a composition ratio of - /SiO ₂ 0.01 to 1.0 A/Al ₂ O ₃ 0.1 to 200 (A is an aliphatic carboxylic acid or its salt) A method for converting aromatic hydrocarbons, which comprises contacting a catalyst containing ethylbenzene with xylenes containing ethylbenzene in the presence of hydrogen. 2. The method of claim 1, wherein the catalyst comprises the crystalline aluminosilicate, mordenite-type zeolite, and rhenium.