JP2005224793A - Conversion catalyst for ethylbenzene-containing xylenes, and conversion method of ethylbenzene- containing xylenes using the catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conversion catalyst for ethylbenzene-containing xylenes and a conversion method using the catalyst, in details, a method in which ethylbenzene-containing xylenes are subjected to hydrogenation/dealkylation of ethylbenzene to produce benzene and ethane at a high level, and at the same time, loss of xylene is reduced when isomerizing o-xylene and m-xylene to p-xylene. <P>SOLUTION: For the conversion catalyst, an X-ray diffraction intensity ratio of crystal lattice plane space d of 0.386±0.008 nm to crystal lattice plane space d of 0.196±0.002 nm, is 100:7 to 100:35. In this conversion method, the catalyst is brought into contact with ethylbenzene-containing xylenes in the presence of hydrogen. By this conversion method, ethylbenzene is hydrogenated/dealkylated to produce benzene and ethane at a high level, and at the same time, loss of xylene is reduced when isomerizing o-xylene and m-xylene to p-xylene. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a conversion catalyst for ethylbenzene-containing xylenes and a method using the catalyst. Specifically, xylenes containing ethylbenzene are contacted with a specific catalyst in the gas phase in the presence of hydrogen, and ethylbenzene is mainly converted to benzene. It relates to a method of dealkylating and simultaneously isomerizing ortho-xylene and / or meta-xylene to para-xylene.

  Among the xylene mixtures, para-xylene is particularly important now industrially. As a crude raw material for synthetic fiber polyester, paraxylene has so far increased in demand. This trend is expected to remain unchanged. Since orthoxylene and meta-xylene, which are xylene isomers other than paraxylene, have a significantly lower demand than para-xylene, conversion to para-xylene is industrially important.

  Since the isomers of xylene and ethylbenzene are close to each other in boiling point, it is virtually impossible to separate para-xylene by distillation, so the cryogenic separation method or the adsorption separation method is used. Yes. In the case of the cryogenic separation method, the recovery rate of para-xylene per pass is limited because of the eutectic point, and at most (60%) / (1 pass). As a result, the para-xylene concentration in the raffinate fluid after recovery of para-xylene is quite high. In the case of the cryogenic separation method, the higher the para-xylene concentration in the feedstock, the higher the para-xylene recovery rate per pass.

  On the other hand, in the adsorption separation method, para-xylene can be recovered 100% per pass. That is, the para-xylene concentration in the raffinate fluid after adsorptive separation is very low and can be made almost zero. However, in the case of the adsorption separation method, the component that most inhibits the separation of para-xylene in the C8 aromatic hydrocarbon mixture is ethylbenzene. Therefore, reducing the ethylbenzene concentration in the feedstock supplied to the adsorption separation can improve the paraxylene adsorption separation performance and further increase the paraxylene concentration in the feedstock. Can improve the production capacity of paraxylene.

  Because of the situation, the xylene feed fed to the separation process increases the paraxylene concentration in the C8 aromatic hydrocarbon mixture by reducing the ethylbenzene concentration as low as possible and increasing the paraxylene concentration in xylene. This is very important.

  In general, xylene raw materials that are industrially used are reformed xylene in the form of reformed oil obtained by reforming naphtha, followed by aromatic extraction and / or fractional distillation, or cracked gasoline by-produced by thermal decomposition of naphtha. Is a cracked oil xylene obtained by aromatic extraction and / or fractional distillation. What is particularly characteristic in the cracked oil-based xylene is that the ethylbenzene concentration is more than twice as high as that of the modified oil-based xylene. An example of the typical composition is shown in the table below.

Table Composition of xylene Modified oil system Decomposed oil system Ethylbenzene 18 wt% 39 wt%
Paraxylene 19 13
Metaxylene 42 32
Orthoxylene 21 16
Thus, in general, a considerable amount of ethylbenzene is present in the xylene mixture. However, unless ethylbenzene is removed by any means, ethylbenzene accumulates as the separation process and isomerization process are recycled, and its concentration It will be an unfavorable situation that will increase. For this reason, the current situation is that reformed oil xylene with a low ethylbenzene concentration is preferably used as a fresh feedstock. As a result, pyrolysis oil xylene has been reviewed. In any case, it is necessary to reduce the concentration of ethylbenzene, and several methods have been implemented industrially and several methods have been proposed. The methods can be broadly classified, one is a method of separating ethylbenzene as it is, and the other is a method of converting it into other useful compounds by reaction.

  An example of a method for separating ethylbenzene is a distillation method. In the case of this method, since the boiling point difference with xylenes is small, it is necessary to use ultra-precise distillation, which requires an industrially huge capital investment, and has a high operating cost, which is an economically disadvantageous method. . There is also a proposal to separate ethylbenzene by an adsorptive separation method, but the separation performance is not fully satisfactory.

There are several ways of removing ethylbenzene that can be converted to other useful components. The most typical method is
(1) A method for converting ethylbenzene into xylene (for example, see Patent Document 1)
(2) A method of converting ethylbenzene into benzene and diethylbenzene by a disproportionation reaction (see, for example, Patent Document 2)
(3) A method of converting ethylbenzene into benzene and ethane by dealkylation reaction (see, for example, Patent Document 3)
Can be mentioned.

  Among the above methods, in the method (1) of converting ethylbenzene into xylene, it is essential that the catalyst contains platinum which is a very expensive noble metal. Furthermore, in order to convert ethylbenzene into xylene, intervening non-aromatic components such as naphthene and paraffin are necessary in the reaction mechanism, and the concentration of the product present in the product ranges from several percent to several tens percent. It extends. Furthermore, since the conversion rate of ethylbenzene is regulated by the thermodynamic equilibrium, there are disadvantages such as its limitations.

In addition, in the method (2) of converting ethylbenzene into benzene and diethylbenzene by disproportionation reaction, the produced benzene is hydrogenated to cyclohexane and there is a great demand as a crude raw material for synthetic fiber nylon. However, it is necessary to convert to other useful compounds, which is economically disadvantageous.
Recently, the method of converting ethylbenzene (3) into benzene and ethane by dealkylation reaction has become the mainstream.

  When dealkylating ethylbenzene from xylene isomer mixture raw material containing ethylbenzene, converting it to benzene, and isomerizing ortho-xylene and meta-xylene to para-xylene, it is necessary to increase the ethylbenzene conversion rate as much as possible. It is preferable to reduce the xylene loss, and it is preferable to reduce the xylene basic unit of para-xylene production and reduce the para-xylene production cost. From the standpoint, attempts to use zeolite with a crystal size larger than 1 micron (for example, Patent Document 4), attempts to reduce the diffusion rate of ortho-xylene (for example, Patent Document 5), and the silica / alumina molar ratio is 500 or more. Attempts have been made to use extremely high zeolite (for example, Patent Document 6).

However, the xylene loss with respect to the ethylbenzene conversion rate is still high even in the method of concern, and if the xylene loss is suppressed and the ethylbenzene conversion rate is increased, the isomerization rate from ortho xylene and meta-xylene to para-xylene is not high enough. There is no current situation.
Japanese Examined Patent Publication No. 49-46606 (Example 3 on page 3) Japanese Examined Patent Publication No. 53-41657 (page 10, column 19, lines 32 to 33) Japanese Patent Laid-Open No. 57-200239 (Examples 2 to 4 on pages 7 to 8) Japanese Examined Patent Publication No. 62-56138 (Examples 4 to 6 on pages 10 to 11) Japanese Examined Patent Publication No. 8-16074 (Examples on pages 5-7) US Pat. No. 4,163,028 (Examples 1 and 3 on page 14)

  The present invention relates to a conversion catalyst for ethylbenzene-containing xylenes and a method using the catalyst, and more specifically, xylenes containing ethylbenzene are treated to hydrodealkylate ethylbenzene into benzene and ethane at a high level, and at the same time, ortho-xylene, It is an object of the present invention to provide a method for reducing xylene loss when isomerizing meta-xylene to para-xylene.

  In order to solve the above problems, the present invention has the following configuration. That is, the X-ray diffraction intensity ratio of the crystal lattice spacing d value 0.386 ± 0.008 nm attributed to MFI-type zeolite and the crystal lattice spacing d value 0.196 ± 0.002 nm attributed to alumina is from 100 to 7. A conversion catalyst for ethylbenzene-containing xylenes containing MFI-type zeolite and alumina, which is 100 to 35, and a method for converting ethylbenzene-containing xylenes by contacting the ethylbenzene-containing xylenes with the above catalyst.

  In the present invention, the X-ray diffraction intensity ratio between the crystal lattice spacing d value 0.386 ± 0.008 nm attributed to MFI-type zeolite and the crystal lattice spacing d value 0.196 ± 0.002 nm attributed to alumina is 100 pairs. By using a catalyst containing MFI-type zeolite and alumina, which is 7 to 100 to 35, ethylbenzene is dealkylated at a high level, and orthoxylene and meta-xylene are isomerized to para-xylene. It is possible to reduce the loss.

  Of the xylene mixtures, the industrially particularly important one is para-xylene, which is a raw material for synthetic fiber polyester. Since orthoxylene and meta-xylene, which are xylene isomers other than paraxylene, have a significantly lower demand than para-xylene, conversion to para-xylene is industrially important. By using the catalyst according to the present invention, xylene loss is suppressed from ethylbenzene-containing xylenes, and ethylbenzene is efficiently dealkylated to benzene that can be easily separated from xylenes. At the same time, ortho-xylene and meta-xylene are converted to para-xylene. Isomerizable.

  As a feedstock according to the present invention, by-product by thermal decomposition of reformed oil xylene or naphtha obtained by catalytically reforming naphtha obtained in the petroleum refining process, followed by aromatic extraction and / or fractional distillation treatment. This is a cracked oil-based xylene obtained by aromatic extraction and / or fractional distillation of cracked gasoline. Both the modified oil xylene and the cracked oil xylene are xylene isomer mixtures containing ethylbenzene.

  Since these xylene isomer mixtures containing ethylbenzene contain para-xylene close to the equilibrium concentration, they are first sent to the para-xylene separation step to separate para-xylene, and the raffinate component having a low para-xylene concentration is converted into the isomerization step. At the same time as the conversion of ethylbenzene, the isomerization reaction to para-xylene is carried out, the lighter and heavier boiling components than xylene are removed by fractional distillation, and again combined with the fresh feedstock, the para-xylene separation process To separate the para-xylene and recycle the raffinate having a low para-xylene concentration. Furthermore, recently, in order to increase the para-xylene concentration in the feed liquid supplied to the para-xylene separation step and to improve the para-xylene separation performance, a xylene isomer mixture containing fresh ethylbenzene is previously contacted with a catalyst. Attempts have been made to reduce the ethylbenzene concentration by hydrodealkylating ethylbenzene to benzene and ethane. In this case, a method of contacting the xylene isomer mixture containing fresh ethylbenzene outside the loop for circulating the raffinate component after separation of para-xylene into the isomerization step, and an isomerization step of the raffinate component after separation of para-xylene There is a method of supplying directly to the isomerization catalyst existing in the loop to be circulated. Any method is preferably used.

  The zeolite used in the present invention is an MFI type zeolite. MFI-type zeolite has the characteristic X-ray diffraction pattern shown in the table below. The measurement of the X-ray diffraction pattern is performed by a method of obtaining a diffraction pattern using a Geiger counter spectroscope equipped with a recording device by irradiation with copper K-α rays.

Table X-ray diffraction pattern of MFI-type zeolite Lattice spacing Relative intensity d (nm) (I / I ₀ )
1.12 ± 0.02 S
1.01 ± 0.02 S
0.98 ± 0.02 M
0.637 ± 0.01 W
0.600 ± 0.01 W
0.571 ± 0.01 W
0.558 ± 0.01 W
0.437 ± 0.008 W
0.427 ± 0.008 W
0.386 ± 0.008 VS
0.382 ± 0.008 VS
0.375 ± 0.008 S
0.372 ± 0.008 S
0.366 ± 0.005 M
0.300 ± 0.005 M
0.200 ± 0.005 W
However, the relative intensity (100 I / I ₀ ) was expressed as VS = very strong, S = strong, M = intermediate strength, and W = weak.

The synthesis method of MFI-type zeolite is a ZSM-5 synthesis method in which tetrapropylammonium hydroxide is added to an aqueous reaction mixture as shown in Japanese Patent Publication No. 46-10064, Japanese Patent Publication No. 3-45010. A TSZ synthesis method synthesized from an aqueous reaction mixture consisting essentially of an inorganic reaction material as shown in FIG. 2, an aliphatic carboxylic acid or a derivative thereof as shown in Japanese Patent Publication No. 60-35284 is added to the aqueous reaction mixture And a pentasil type zeolite synthesis method. Among the suspended MFI type zeolites, preferred MFI type zeolites for the present invention have a crystallite major axis and minor axis of 0.7 to 2.5 microns, and silica / alumina (hereinafter “SiO ₂ / Al ₂ O”). ₃ "(abbreviated as ₃ ") is a zeolite having a molar ratio of 30 to 55. A more preferred MFI type zeolite is a zeolite having a major axis and a minor axis of the crystallite of 1 to 2.5 microns, and a SiO ₂ / Al ₂ O ₃ molar ratio of 35 to 45. For catalysts prepared from MFI-type zeolites with crystallite sizes of less than 1 micron and even less than 0.5 microns, xylene losses increase when xylenes containing ethylbenzene are converted. The main cause is transalkylation of the side chain methyl group of xylene or the side chain ethyl group of ethylbenzene. Suspended transalkylation is considered to occur on the solid acid sites on the outer surface of the crystal because the crystal surface area of the crystal increases as the crystallites of the MFI zeolite become smaller. Unlike the inside of MFI-type zeolite pores, the outer surface of the crystal is free space, so it is considered that transalkylation, which is a bimolecular reaction, easily occurs. When the crystallite becomes larger than 2.5 microns, the reaction activity decreases. This is thought to be due to the fact that, as the crystallite of the MFI-type zeolite becomes larger, it becomes difficult for the reaction molecules to reach deep inside the crystallite and the utilization rate of the pore space decreases. On the other hand, when the SiO ₂ / Al ₂ O ₃ molar ratio of the MFI type zeolite is 35 or even smaller than 30, xylene loss increases. This is presumably because the methyl group transalkylation reaction activity is increased by increasing the solid acid sites on the outer surface of the crystal. When the SiO ₂ / Al ₂ O ₃ molar ratio of MFI-type zeolite is 45 or more than 55, the dealkylation activity of ethylbenzene and the isomerization activity of xylene are lowered. It is considered that the solid acid point of the zeolite decreases when the MFI type zeolite has a SiO ₂ / Al ₂ O ₃ molar ratio of 45 or more than 55.

  However, in the case of an MFI-type zeolite having a crystallite major axis and minor axis of 0.03 to 0.7 microns and a silica / alumina molar ratio of 18 to 30, it is surprising to include strontium and / or barium. It was found that the transalkylation of the side chain methyl group of xylene or the side chain ethyl group of ethylbenzene was remarkably suppressed. It is presumed that due to the ionic radius of strontium and barium being larger than the same alkaline earth metals magnesium and calcium, the solid acid sites on the crystal outer surface in the pores are selectively reduced.

Japanese Patent Publication No. 46-10064, column 5, lines 8 to 11 describing a synthesis method of ZSM-5 using tetrapropylammonium hydroxide, which is an organic nitrogen-containing compound. Is made of small crystals of about 1 micron together with some gel particles ", and ZSM-5 having a SiO ₂ / Al ₂ O ₃ molar ratio of 31.1 described in Example 2 of the publication. Are described as very small crystals (on the order of 1 micron) with some gelled particles.

In the presence of an organic nitrogen-containing compound, when the SiO ₂ / Al ₂ O ₃ molar ratio is decreased, a bulky organic nitrogen-containing compound is present at the cation exchange site, so that crystal distortion increases with crystal growth. As a result, the crystallites cannot grow and the average crystal size is usually less than 1 micron, for example 0.5 microns. On the other hand, in EP26,963A1, the average crystal size of ZSM-5 can be obtained from 1 to 2 microns under a high SiO ₂ / Al ₂ O ₃ molar ratio of 180. This is because SiO ₂ / Al ₂ O ₃ is high, so there are few cation exchange sites. Therefore, it is considered that the organic nitrogen-containing cation present at the cation exchange site is reduced, distortion in crystal growth is small, and the crystal size is increased.

A method for synthesizing an MFI type zeolite having a major axis and a minor axis of a crystallite preferably used in the present invention of 0.7 to 2.5 microns and a silica / alumina molar ratio of 30 to 55 is an organic nitrogen-containing compound. It is preferably synthesized in the absence. Since no organic nitrogen-containing compound is present in the crystal growth process, the crystal distortion is small, and even if the SiO ₂ / Al ₂ O ₃ molar ratio is reduced, it is considered that the crystal remains large to some extent. The crystallite size of zeolite can be easily known with an apparatus such as a field emission scanning electron microscope (FE-SEM). In the MFI type zeolite having a major axis and a minor axis of 0.7 to 2.5 microns of the crystallite of the present invention, the major axis and minor axis of the average crystallite of the zeolite may be in this range. The “average” of the average crystal size mentioned here means that the major axis and the minor axis of the crystallite of the measurement sample (zeolite) are 50% or more, preferably 70% or more, within this range. means. The measurement of the silica / alumina molar ratio can be easily known by atomic absorption method, fluorescent X-ray diffraction method, ICP (inductively coupled plasma) emission spectroscopy or the like.

  Further, a method for synthesizing MFI type zeolite having a major axis and a minor axis of a crystallite preferably used in the present invention of 0.03 to 0.7 microns and a silica / alumina molar ratio of 18 to 30 is an organic-containing method. A zeolite synthesized by any method in the presence or absence of a nitrogen compound can be used, but a zeolite synthesized in the absence of an organic nitrogen-containing compound is preferred. Zeolite synthesized in the presence of an organic nitrogen-containing compound has an organic nitrogen cation. In order to remove organic nitrogen cations, it is usually fired in the presence of oxygen. In this process, zeolite tends to contain crystal lattice defects. Crystal lattice defects are liable to cause a decomposition reaction by a conversion catalytic reaction of an aromatic compound.

  Synthetic zeolite is usually a powder. In order to use zeolite as an industrial catalyst, it is important to mold it to a certain size. In order to hydrodealkylate ethylbenzene, the subject of the present invention, mainly into benzene and ethane, it is necessary to support a hydrogenation component on the catalyst. Examples of the hydrogenation component include rhenium, platinum, and nickel. In particular, rhenium is preferably used because it has little nuclear hydrogenation reaction of phenyl group. To efficiently carry out hydrodealkylation of ethylbenzene to benzene and isomerization of ortho- and meta-xylene to para-xylene in the catalyst, uniformly disperse the MFI-type zeolite crystals in the catalyst particles. It is important that the hydrogenation component be uniformly dispersed and supported in the catalyst particles. To achieve the stated objective, the zeolite powder is mixed and diluted with the inorganic oxide powder. The diluted inorganic oxide preferably used in the present invention is alumina. Known aluminas include boehmite, boehmite gel, dipsite, vialite, norstrandite, diaspore, amorphous alumina gel, and the like. Any alumina can be used, but the particularly preferred diluted alumina is boehmite having a lattice spacing that can be measured by X-ray diffraction shown in the following table. It is possible to add other inorganic oxides to the boehmite to be suspended as required.

Table X-ray diffraction pattern of diluted alumina Lattice spacing Relative intensity d (nm) (I / I ₀ )
0.627 ± 0.02 M
0.317 ± 0.02 M
0.234 ± 0.02 M
0.185 ± 0.01 M

  It is well known that alumina becomes γ, η, δ, α, etc. during the firing process, but boehmite, which is a diluted alumina preferably used in the present invention, undergoes a structural change during the catalyst preparation process according to the present invention. Occurs, and the lattice spacing changes. Alumina in the preferred catalyst form for the present invention is alumina having a lattice spacing d value of 0.196 ± 0.002 nm. In particular, the X-ray diffraction intensity ratio of the lattice spacing d value attributed to alumina to 0.196 ± 0.002 nm with respect to the lattice spacing distance d value 0.386 ± 0.008 nm attributed to MFI-type zeolite in the catalyst is 100 pairs. A catalyst that is 7 to 100 to 35 is used. The measurement of the X-ray diffraction intensity ratio is performed as follows. That is, the catalyst is pulverized to form a powder, and a diffraction pattern is obtained using a Geiger counter spectrometer equipped with a recording device by copper K-α ray X-ray irradiation. From the obtained diffraction pattern, the intensity obtained by subtracting the background from the peak intensity of the highest intensity peak existing at the lattice plane spacing d value of 0.386 ± 0.008 nm and the lattice plane spacing d value of 0.196 ± 0.002 nm. It is easily obtained from the ratio. This intensity ratio is a characteristic unique to the catalyst according to the present invention. By using a catalyst having an X-ray intensity ratio of 100: 7 to 100: 35, xylene loss can be reduced.

  MFI-type zeolite and diluted alumina, which are catalyst raw materials, are preferably used in powder form and need to be molded for use as an industrial catalyst. Examples of the molding method include a compression molding method, a rolling method, and an extrusion method, and the extrusion method is more preferable. In the extrusion method, MFI-type zeolite powder and alumina powder that uniformly dilutes the zeolite powder are mixed with inorganic binders such as alumina sol, alumina gel, bentonite, kaolin, and so on. Sodium dodecylbenzenesulfonate, sorbitan lauric acid monoester, sorbitan Surface activity such as palmitic acid monoester, sorbitan stearic acid monoester, sorbitan stearic acid triester, sorbitan oleic acid monoester, sorbitan oleic acid triester, ethylene oxide adducts thereof (for example, span, twin, etc., manufactured by ICI) An agent is added as a molding aid and kneaded. More preferred binders are alumina sol and alumina gel. The preferred blending ratio for forming the catalyst is expressed in terms of absolute dryness (calculated from the loss of ignition when calcined at 500 ° C. for 20 minutes), 15 to 80 parts by weight of MFI zeolite, 85 to 20 parts by weight of diluted alumina, inorganic The binder is 0 to 30 parts by weight. A more preferable blending ratio is 20 to 60 parts by weight of MFI type zeolite, 80 to 40 parts by weight of diluted alumina, and 0 to 30 parts by weight of inorganic binder. When the inorganic binder is alumina such as alumina sol or alumina gel, the MFI type zeolite is 15 to 80 parts by weight, more preferably 20 to 60 parts by weight, alumina is diluted alumina and alumina sol which is an inorganic binder, and the alumina based on the alumina gel is combined. Thus, 85 to 20 parts by weight, more preferably 80 to 60 parts by weight is preferably used. The kneaded material is extruded from the screen. Industrially, for example, an extruder called an extruder is used. The kneaded product extruded from the screen becomes a cylindrical product. The size of the molded body is determined by the screen diameter to be used. The screen diameter is preferably 0.2 to 2.0 mmφ, more preferably 0.5 to 1.7 mmφ, and cylindrical catalyst particles having a catalyst particle diameter of 0.2 to 2.0 mm are obtained. . The columnar molded body extruded from the screen is preferably treated with a malmerizer to round off the corners. The molded body thus molded has a cylindrical shape with a diameter of 0.2 to 2.0 mmφ and a length of about 0.1 to 10 mm. The molded body is dried at 50 to 250 ° C. After drying, it is fired at 250 to 650 ° C., preferably 350 to 600 ° C., in order to improve the molding strength. When the catalyst particle diameter is smaller than 2.0 mm, and more preferably smaller than 1.7 mmφ, the diffusion of ethylbenzene and xylene isomers to the reaction active sites existing in the catalyst particle may be slow under the reaction conditions. And the reaction is not suppressed, which is preferable. In particular, the isomerization reaction of ortho-xylene and meta-xylene to para-xylene does not slow down, and the side reaction does not increase relatively. On the other hand, when the catalyst particle diameter is larger than 0.2 mm, the pressure loss during the reaction does not increase, which is preferable.

The molded body thus prepared is subjected to ion exchange treatment in order to impart solid acidity. As a method for imparting solid acidity, ion exchange treatment is performed with a compound containing ammonium ions (for example, NH ₄ Cl, NH ₄ NO ₃ , (NH ₄ ) ₂ SO _4, etc.), and NH ₄ ions are added to the ion exchange site of the zeolite. After that, it is converted into hydrogen ions by drying and calcination, or directly with an acid-containing compound (for example, HCl, HNO ₃ , H ₃ PO _4, etc.) at the ion exchange site of the zeolite. Although there is a method of introducing ions, the latter is preferably subjected to ion exchange treatment with the former, that is, a compound containing ammonium ions, because the latter may destroy the zeolite structure. In the present invention, it is preferable that an alkaline earth metal ion is present in addition to the hydrogen ion. Examples of the alkaline earth metal include magnesium, calcium, strontium, and barium. In particular, calcium, strontium, and barium are preferable because they reduce xylene loss. In the case of MFI-type zeolites with a crystallite major and minor axis of 0.03 to 0.7 microns and a silica / alumina molar ratio of 18 to 30, strontium and barium significantly reduce xylene loss. Therefore, it is preferable. In the alkaline earth metal ion exchange, an ion exchange treatment is performed with a compound containing an alkaline earth metal ion (for example, chloride, nitrate, acetate, etc.), and the alkaline earth metal ion is introduced into the ion exchange site of the zeolite. Alkaline earth metal ion exchange may be performed simultaneously with ammonium ion exchange, before ammonium ion exchange, or after ammonium ion exchange. In addition, for introducing the alkaline earth metal, a method in which a compound containing an alkaline earth metal is added and introduced when the MFI type zeolite powder is kneaded and formed with the diluted alumina powder and the binder is also preferably used. A preferable amount of the alkaline earth metal is 0.05 to 5% by weight, more preferably 0.1 to 2% by weight, based on the catalyst (the sum of the MFI type zeolite and the inorganic oxide).

  Furthermore, the introduction of silver ions is preferably used because it improves the catalytic activity. The preferred amount of silver ions is 0.1 to 5% by weight. As an introduction method, any of an ion exchange method, an impregnation method, and a kneading method can be used, but an ion exchange method is more preferable. In the case of silver ion exchange, it may be carried out simultaneously with alkaline earth metal ion exchange and ammonium ion exchange, or may be carried out separately. Silver nitrate is preferably used as the compound containing silver ions.

  After being treated in this way, the hydrogenation active component is supported. By making hydrogen present in the catalytic reaction system and supporting the hydrogenation active component, the hydrogen deethylation reaction activity of ethylbenzene to benzene and ethane is improved, and coking on the catalyst is suppressed, and the catalyst performance is improved. It is possible to prevent deterioration over time. As the hydrogenation active metal, rhenium, platinum or nickel is preferably used. In particular, rhenium is preferably used. Rhenium may exist in a metal form or in the form of an oxide, sulfide, selenide or the like, and those that can be particularly preferably used as the rhenium component include perrhenic acid and ammonium perrhenate. Examples of the platinum component that can be particularly preferably used include chloroplatinic acid and ammonium chloroplatinate. In any case, the supported amount of the hydrogenation active component is 0.005 to 1.5% by weight in terms of metal based on the catalyst. If the amount of the hydrogenation active component is too small, the conversion activity of ethylbenzene is not sufficient.

  After supporting the hydrogenation active component, it is dried and fired. The ammonium ion present at the ion exchange point of the MFI type zeolite becomes a hydrogen ion and imparts acidity to the catalyst. Preferable firing conditions are 300 to 650 ° C. in an oxygen-containing atmosphere.

  The catalyst of the present invention is preferably subjected to sulfiding treatment after supporting the hydrogenation active component. Usually, it is carried out at room temperature to 500 ° C, preferably 100 to 450 ° C in a hydrogen sulfide stream. By the sulfiding treatment, the decomposition activity of the alkyl aromatic hydrocarbon can be suppressed.

The method for converting xylenes containing ethylbenzene in the present invention comprises contacting the xylenes with the catalyst (the catalyst of the present invention) in the presence of hydrogen. The contact conditions include a reaction temperature of 300 to 480 ° C., preferably 350 to 480 ° C., a reaction pressure of 0.2 to 5 MPa, preferably 0.4 to 3 MPa, and an H ₂ / C 8 aromatic hydrocarbon mixture (ethylbenzene 20 mol / mol from xylenes) 0.2 containing, 30 hr ^-1 and preferably from 10 mol / mol, the weight hourly space velocity 0.2 1, preferably between 2 20 hr ^-1.

  The C8 aromatic hydrocarbon mixture used in the present invention is not particularly limited as long as it contains ethylbenzene, but the C8 aromatic hydrocarbon mixture obtained by reforming naphtha and subsequent extraction and / or fractional distillation. , Without undergoing a process of reforming naphtha and extracting naphthene and paraffin, naphthene having about 9 carbon atoms, C8 aromatic hydrocarbon mixture containing paraffin, or cracked gasoline by-produced by thermal decomposition of naphtha A raw material for producing p-xylene such as a C8 aromatic hydrocarbon mixture obtained by extraction and / or fractional distillation is preferably used.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples.

Example 1 (Synthesis of MFI-type zeolite and preparation of catalyst A)
Caustic soda aqueous solution (NaOH content 48.6% by weight, H ₂ O content 51.4% by weight, Mitaka Pure Chemical Laboratories) 40.9 grams, tartaric acid (Kirk) 15.7 grams diluted to 529 grams of water, Dissolved. 12.83 grams of sodium aluminate solution (Al ₂ O ₃ content 18.9% by weight, NaOH 25.4% by weight, H ₂ O 55.7% by weight, Daiso Corporation) was added to this solution to obtain a uniform solution. Hydrous silicic acid (SiO ₂ content 90.4% by weight, NaOH content 0.22% by weight, Al ₂ O ₃ content 0.26% by weight, H ₂ O content 9.12% by weight, nip seal VN-3, Nippon Silica Co., Ltd.) 95.2 grams was gradually added with stirring to prepare a uniform slurry aqueous reaction mixture. The composition ratio (molar ratio) of this reaction mixture was as follows.
SiO ₂ / Al ₂ O ₃ 55
OH ⁻ / SiO ₂ 0.26
A / Al ₂ O ₃ 4.0 (A: tartrate)
H ₂ O / SiO ₂ 22

  The reaction mixture was sealed in a 1000 ml autoclave and then reacted at 160 ° C. for 72 hours with stirring at 800 rpm. After completion of the reaction, washing with distilled water 5 times and filtration were repeated, followed by drying at about 120 ° C. overnight.

The results obtained by measuring the obtained product with an X-ray diffractometer using Cu tube and Kα ray are shown in FIG. The obtained zeolite was found to be MFI type zeolite.
The result of FE-SEM observation of this zeolite is shown in FIG. The average crystallite size was 1.8 microns for the major axis and 1.3 microns for the minor axis.
The SiO ₂ / Al ₂ O ₃ molar ratio of this zeolite was 43 as a result of fluorescent X-ray diffraction analysis.

10 grams of MFI-type zeolite synthesized as described above (calculated from the loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL, Al ₂ O ₃ content 75 wt%, X 40 g (30 g as Al ₂ O ₃ ) of the line diffractogram (shown in FIG. 3), 60 g of alumina sol (Al ₂ O ₃ content 10% by weight, Nissan Chemical Co., Ltd.) (6 g as Al ₂ O ₃ ) In addition, thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact, put it in an aqueous solution in which 2.2 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 1.3 grams of calcium chloride dihydrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 mg of Re at room temperature and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst A”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.17% by weight as Ca and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy, and found to be 0.36% by weight as Re metal. FIG. 4 shows the result of pulverizing this catalyst and measuring the X-ray diffraction. From FIG. 4, the X-ray diffraction intensity ratio between the crystal lattice spacing d value of 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value of 0.196 nm (2θ = 46.18 °) is 100: 30. It was. In addition, d (nm) value was calculated | required from Bragg's law 2d * Sin (theta) = n * (lambda) (however, n = 1, (lambda) = 0.15406nm) from 2 (theta) (degree) value of an X-ray diffraction diagram.

Comparative Example 1 (Preparation of catalyst B)
10 g of α-alumina (Wako Pure Chemical Industries, Ltd., X-ray diffractogram) based on absolute drying standard (calculated from loss of ignition when calcined at 500 ° C. for 20 minutes) of MFI type zeolite synthesized in the same manner as in Example 1. 5) on an absolute dry basis as Al ₂ O ₃ , 30 grams of alumina sol (Nissan Chemical Industry Co., Ltd., Al ₂ O ₃ content 10 wt%) 60 grams (6 grams as Al ₂ O ₃ ) were added and mixed well . Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact, put it in an aqueous solution in which 2.2 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 1.3 grams of calcium chloride dihydrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Thereafter, the liquid was drained and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst B”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.18% by weight as Ca and 0.2% by weight as Na. The amount of rhenium supported in the catalyst was 0.21% by weight as Re metal as measured by ICP emission spectroscopy. FIG. 6 shows the result of pulverizing this catalyst and measuring the X-ray diffraction. From FIG. 6, a crystal lattice spacing d value of 0.386 nm (2θ = 23.04 °) was observed, but a crystal lattice spacing d value of 0.196 nm (2θ = 46.18 °) was hardly recognized.

Comparative Example 2 (Preparation of catalyst C)
MFI-type zeolite synthesized in the same manner as in Example 1 was 40 g of alumina sol (Nissan Chemical Industry Co., Ltd., Al ₂ O ₃ content: 10% by weight based on absolute dryness (calculated from loss of ignition when calcined at 500 ° C. for 20 minutes). %) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact and place it in an aqueous solution in which 8.8 grams of ammonium chloride (Sigma Aldrich) and 5.2 grams of calcium chloride dihydrate (Kirk) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst C”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.71% by weight as Ca and 0.5% by weight as Na. The amount of rhenium supported in the catalyst was 0.21% by weight as Re metal as measured by ICP emission spectroscopy. FIG. 7 shows the result of pulverizing this catalyst and measuring the X-ray diffraction. From FIG. 7, the crystal lattice spacing d value of 0.386 nm (2θ = 23.04 °) is recognized, but the crystal lattice spacing d value of 0.196 nm (2θ = 46.18 °) is not recognized. Even if it is recognized, the maximum is less than 100 to 5.

Example 2 (Preparation of catalyst D)
MFI-type zeolite synthesized in the same manner as in Example 1 was 20 grams on an absolute dry basis (calculated from the loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL, Al ₂ O ₃ content 75% by weight, X-ray diffraction diagram is shown in FIG. 3) 27 grams (20.2 grams as Al ₂ O ₃ ), alumina sol (Nissan Chemical Co., Ltd., Al ₂ O ₃ content 10 wt%) 60 grams (as Al ₂ O ₃ ) 6 grams) and mixed well. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact, put it in an aqueous solution in which 2.8 grams of ammonium chloride (Sigma Aldrich) and 3.2 grams of calcium chloride dihydrate (Kirk) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst D”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.43% by weight as Ca and 0.6% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy, and found to be 0.37% by weight as Re metal. FIG. 8 shows the result of pulverizing this catalyst and measuring the X-ray diffraction. From FIG. 8, the X-ray diffraction intensity ratio between the crystal lattice spacing d value of 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value of 0.196 nm (2θ = 46.18 °) is 100: 10. It was.

Example 3 (Preparation of catalyst E)
10 g of MFI type zeolite synthesized in the same manner as in Example 1 on an absolute dry basis (calculated from the loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL, Al ₂ O ₃ content 75% by weight, X-ray diffractogram shown in FIG. 3 is 40 grams (30 grams as Al ₂ O ₃ ), alumina sol (Nissan Chemical Co., Ltd., Al ₂ O ₃ content 10% by weight) 60 grams (6 grams as Al ₂ O ₃ ) ), 1.5 grams of barium acetate (Kirk Co., Ltd.) was added and mixed well. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 575 ° C. and fired at 575 ° C. for 2 hours. Twenty grams of the baked compact was taken and placed in an aqueous solution in which 1.1 grams of ammonium chloride (Sigma Aldrich) was dissolved in 60 grams of distilled water and treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst E”. As a result of measuring the barium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.39% by weight as Ba and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy, and found to be 0.37% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 9.

Example 4 (Preparation of catalyst F)
A catalyst prepared in the same manner as in Example 1, which was immersed in a solution containing 100 ppm by weight of Pt as a Pt with respect to the catalyst instead of rhenium. Pt supported on the catalyst was 69 ppm by weight as measured by ICP emission spectroscopy. This catalyst is abbreviated as “catalyst F”.

Example 5 (Synthesis of MFI-type zeolite and preparation of catalyst G)
Caustic soda aqueous solution (NaOH content 48.6% by weight, H ₂ O content 51.4% by weight, Miwaka Pure Chemical Research Laboratory) 37.1 grams, tartaric acid (Kirk) 15.1 grams diluted to 529 grams of water, Dissolved. 14.25 grams of sodium aluminate solution (Al ₂ O ₃ content 18.9 wt%, NaOH 25.4 wt%, H ₂ O 55.7 wt%, Daiso Corporation) was added to this solution to obtain a uniform solution. Hydrous silicic acid (SiO ₂ content 90.4% by weight, NaOH content 0.22% by weight, Al ₂ O ₃ content 0.26% by weight, H ₂ O content 9.12% by weight, nip seal VN-3, Nippon Silica Co., Ltd.) 95.2 grams was gradually added with stirring to prepare a uniform slurry aqueous reaction mixture. The composition ratio (molar ratio) of this reaction mixture was as follows.
SiO ₂ / Al ₂ O ₃ 50
OH ⁻ / SiO ₂ 0.24
A / Al ₂ O ₃ 3.5 (A: tartrate)
H ₂ O / SiO ₂ 22

  The reaction mixture was sealed in a 1000 ml autoclave and then reacted at 160 ° C. for 72 hours with stirring at 800 rpm. After completion of the reaction, washing with distilled water 5 times and filtration were repeated, followed by drying at about 120 ° C. overnight.

As a result of measuring the obtained product with an X-ray diffractometer using Cu tube and Kα ray, it was found that the obtained zeolite was MFI type zeolite.
The result of FE-SEM observation of this zeolite is shown in FIG. The average crystallite size was 1.3 microns long and 1.1 microns short.
As a result of fluorescent X-ray diffraction analysis, the SiO ₂ / Al ₂ O ₃ molar ratio of this zeolite was 37.

10 grams of MFI-type zeolite synthesized as described above (calculated from the loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL, Al ₂ O ₃ content 75 wt%, X 40 g (30 g as Al ₂ O ₃ ) of the line diffractogram (shown in FIG. 3), 60 g of alumina sol (Al ₂ O ₃ content 10% by weight, Nissan Chemical Co., Ltd.) (6 g as Al ₂ O ₃ ) In addition, thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact and place it in an aqueous solution in which 1.1 grams of ammonium chloride (Sigma Aldrich) and 1.3 grams of calcium chloride dihydrate (Kirk) are dissolved in 60 grams of distilled water. Treated at 0 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed in 30 ml of a perrhenic acid aqueous solution (Rare Metal Company, Ltd.) containing 100 mg of Re at room temperature and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter referred to as “catalyst G”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.18% by weight as Ca and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was 0.47% by weight as Re metal as measured by ICP emission spectroscopy. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 9.

Example 6 (Preparation of catalyst H)
MFI-type zeolite synthesized in the same manner as in Example 5 was 15 grams on the basis of absolute dryness (calculated from loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL, Al ₂ O ₃ content 75% by weight) , X-ray diffraction diagram is shown in FIG. 3) 34 grams (25.5 grams as Al ₂ O ₃ ), alumina sol (Al ₂ O ₃ content 10 wt%, Nissan Chemical Industries, Ltd.) 60 grams (Al ₂ O ₃ 6 grams) and 3.0 grams of calcium chloride dihydrate and mixed well. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. 20 grams of the baked compact was taken and placed in an aqueous solution in which 1.6 grams of ammonium chloride (Sigma Aldrich) was dissolved in 60 grams of distilled water, and treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst H”. As a result of measuring the calcium content and sodium content in the catalyst by the atomic absorption method, it was 0.37% by weight as Ca and 0.2% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy, and as a result, it was 0.38% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 15.

Example 7 (Preparation of catalyst I)
The catalyst was prepared in the same manner as in Example 5. In place of rhenium, a nickel nitrate aqueous solution (Hayashi Junyaku Kogyo Co., Ltd.) was immersed in a solution containing 1000 ppm by weight of Ni with respect to the catalyst. Ni supported on the catalyst was 850 ppm by weight as measured by ICP emission spectroscopy. This catalyst is abbreviated as “catalyst I”.

Example 8 (Preparation of catalyst J)
Using the same raw materials as in Example 1, an aqueous reaction mixture having the following composition was prepared.
SiO ₂ / Al ₂ O ₃ 77
OH ⁻ / SiO ₂ 0.30
A / Al ₂ O ₃ 5.0 (A: tartrate)
H ₂ O / SiO ₂ 25

  The reaction mixture was sealed in a 1000 ml autoclave and then reacted at 160 ° C. for 72 hours with stirring at 800 rpm. After completion of the reaction, washing with distilled water 5 times and filtration were repeated, followed by drying at about 120 ° C. overnight.

As a result of measuring the obtained product with an X-ray diffractometer using Cu tube and Kα ray, it was found that the obtained zeolite was MFI type zeolite.
The result of FE-SEM observation of this zeolite is shown in FIG. The average crystallite size was 1.5 microns for the major axis and 1.5 microns for the minor axis.
The SiO ₂ / Al ₂ O ₃ molar ratio of this zeolite was 51 as a result of fluorescent X-ray diffraction analysis.

10 grams of MFI-type zeolite synthesized as described above (calculated from the loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL, Al ₂ O ₃ content 75 wt%, X 40 g (30 g as Al ₂ O ₃ ) of the line diffractogram (shown in FIG. 3), 60 g of alumina sol (Al ₂ O ₃ content 10% by weight, Nissan Chemical Co., Ltd.) (6 g as Al ₂ O ₃ ) In addition, thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact and place it in an aqueous solution in which 1.1 grams of ammonium chloride (Sigma Aldrich) and 1.3 grams of calcium chloride dihydrate (Kirk) are dissolved in 60 grams of distilled water. Treated at 0 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed in 30 ml of a perrhenic acid aqueous solution (Rare Metal Company, Ltd.) containing 100 mg of Re at room temperature and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter referred to as “catalyst J”. As a result of measuring the calcium content and sodium content in the catalyst by the atomic absorption method, it was 0.15% by weight as Ca and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy, and found to be 0.37% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100 to 11.

Example 9 (zeolite synthesis) and comparative example 3 (preparation of catalyst K)
Using the same raw materials as in Example 1, an aqueous reaction mixture having the following composition was prepared.
SiO ₂ / Al ₂ O ₃ 30
OH ⁻ / SiO ₂ 0.175
A / Al ₂ O ₃ 2.5 (A: tartrate)
H ₂ O / SiO ₂ 20

  The reaction mixture was sealed in a 1000 ml autoclave and then reacted at 160 ° C. for 72 hours with stirring at 800 rpm. After completion of the reaction, washing with distilled water 5 times and filtration were repeated, followed by drying at about 120 ° C. overnight.

As a result of measuring the obtained product with an X-ray diffractometer using Cu tube and Kα ray, it was found that the obtained zeolite was MFI type zeolite.
The result of FE-SEM observation of this zeolite is shown in FIG. The average crystallite size was 0.05 microns in the long axis and 0.05 microns in the short axis.
As a result of fluorescent X-ray diffraction analysis, the SiO ₂ / Al ₂ O ₃ molar ratio of the zeolite was 25.

  30 grams of the MFI-type zeolite powder synthesized as described above was taken on an absolute dry basis (calculated from the loss of ignition when calcined at 500 ° C. for 20 minutes), and ammonium chloride (Sigma Aldrich Co.) 15 was added to 150 grams of distilled water. .2 grams was placed in a dissolved aqueous solution and treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed by filtration, washed with distilled water 5 times, and filtration was repeated. It was immersed in a perrhenic acid aqueous solution (Rare Metals Co., Ltd.) containing 150 mg of Re at room temperature and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, it was molded into a 3 mmφ cylindrical shape with a tableting machine. 25 grams of the molded body was pulverized and classified with a sieve to obtain 15 grams of a 12 to 24 mesh molded body. This molded body was treated with hydrogen sulfide in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter referred to as “catalyst K”. As a result of measuring the sodium content in the catalyst by atomic absorption spectrometry, it was 0.4% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy and found to be 0.11% by weight as Re metal. FIG. 12 shows the result of pulverizing this catalyst and measuring the X-ray diffraction. From FIG. 12, the X-ray diffraction intensity ratio between the crystal lattice spacing d value of 0.383 nm (2θ = 2.20 °) and the crystal lattice spacing d value of 0.196 nm (2θ = 46.18 °) is 100: 3. there were.

Examples 10-17, Comparative Examples 4-6
For each of the catalysts A to K, 7.5 g was filled in a reaction tube, and xylenes containing ethylbenzene were subjected to a gas phase reaction in the presence of hydrogen. The results are shown in Tables 1 and 2.

  When Examples 10-17 are compared with Comparative Examples 4-6, the X-ray diffraction intensity ratio between the crystal lattice spacing d value of 0.386 ± 0.008 nm and the crystal lattice spacing d value of 0.196 ± 0.002 nm is 100. It can be seen that the conversion catalyst for ethylbenzene-containing xylenes from 7 to 100 to 35 has low xylene loss under reaction conditions with high ethylbenzene conversion and high isomerization to para-xylene.

Example 18 (Preparation of catalyst L)
MFI-type zeolite synthesized in the same manner as in Example 1 on the basis of absolute dryness (calculated from the loss of ignition when calcined at 500 ° C. for 20 minutes), 10 g of hydrous alumina (SASOL, Al ₂ O ₃ content 75% by weight) 40 grams _(Al 2 _{O 3} is 30 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Twenty grams of the fired molded body was taken, placed in an aqueous solution in which 2.2 grams of ammonium chloride (Sigma Aldrich) was dissolved in 60 grams of distilled water, and treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Then, it baked in 540 degreeC for 2 hours in the air. This catalyst is hereinafter abbreviated as “catalyst L”. As a result of measuring the sodium content in the catalyst by atomic absorption spectrometry, it was 0.4% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy and found to be 0.35% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 31.

Example 19 (Preparation of catalyst M)
MFI-type zeolite synthesized in the same manner as in Example 1 on the basis of absolute dryness (calculated from the loss of ignition when calcined at 500 ° C. for 20 minutes), 10 g of hydrous alumina (SASOL, Al ₂ O ₃ content 75% by weight) 40 grams _(Al 2 _{O 3} is 30 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact, put it in an aqueous solution in which 2.2 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 1.8 grams of magnesium chloride hexahydrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst M”. As a result of measuring the magnesium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.13% by weight as Mg and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy and found to be 0.35% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 30.

Example 20 (Preparation of catalyst N)
MFI-type zeolite synthesized in the same manner as in Example 1 on the basis of absolute dryness (calculated from the loss of ignition when calcined at 500 ° C. for 20 minutes), 10 g of hydrous alumina (SASOL, Al ₂ O ₃ content 75% by weight) 40 grams _(Al 2 _{O 3} is 30 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact, put it in an aqueous solution in which 1.1 grams of ammonium chloride (Sigma Aldrich) and 1.8 grams of calcium chloride dihydrate (Kirk) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst N”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.18% by weight as Ca and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy and found to be 0.35% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 30.

Example 21 (Preparation of catalyst O)
MFI-type zeolite synthesized in the same manner as in Example 1 on the basis of absolute dryness (calculated from the loss of ignition when calcined at 500 ° C. for 20 minutes), 10 g of hydrous alumina (SASOL, Al ₂ O ₃ content 75% by weight) 40 grams _(Al 2 _{O 3} is 30 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact, put it in an aqueous solution in which 1.1 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 1.9 grams of strontium nitrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Processed with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst O”. As a result of measuring the strontium content and sodium content in the catalyst by the atomic absorption method, it was 0.20% by weight as Sr and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy and found to be 0.35% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 30.

Example 22 (Preparation of catalyst P)
MFI-type zeolite synthesized in the same manner as in Example 1 was 15 grams on the basis of absolute dryness (calculated from loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL Co., Al ₂ O ₃ content 75% by weight) the 33.3 g _(Al 2 _{O 3} of 25 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded product was extruded through a screen having a hole of 0.5 mmφ. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact and place it in an aqueous solution in which 1.65 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 2.7 grams of calcium chloride dihydrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst P”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.27% by weight as Ca and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy, and found to be 0.37% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 15.

Example 23 (Preparation of catalyst Q)
MFI-type zeolite synthesized in the same manner as in Example 1 was 15 grams on the basis of absolute dryness (calculated from loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL Co., Al ₂ O ₃ content 75% by weight) the 33.3 g _(Al 2 _{O 3} of 25 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a 1.2 mmφ hole. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact and place it in an aqueous solution in which 1.65 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 2.7 grams of calcium chloride dihydrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst Q”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.25 wt% as Ca and 0.3 wt% as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy and found to be 0.35% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 16.

Example 24 (Preparation of catalyst R)
MFI-type zeolite synthesized in the same manner as in Example 1 was 15 grams on the basis of absolute dryness (calculated from loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL Co., Al ₂ O ₃ content 75% by weight) the 33.3 g _(Al 2 _{O 3} of 25 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a hole of 1.5 mmφ. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact and place it in an aqueous solution in which 1.65 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 2.7 grams of calcium chloride dihydrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst R”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.24% by weight as Ca and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy and found to be 0.33% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 15.

Example 25 (Preparation of catalyst S)
MFI-type zeolite synthesized in the same manner as in Example 1 was 15 grams on the basis of absolute dryness (calculated from loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL Co., Al ₂ O ₃ content 75% by weight) the 33.3 g _(Al 2 _{O 3} of 25 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded product was extruded through a screen having a hole of 1.7 mmφ. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact and place it in an aqueous solution in which 1.65 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 2.7 grams of calcium chloride dihydrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed at room temperature in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 milligrams of Re and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst S”. As a result of measuring the calcium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.23% by weight as Ca and 0.3% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy and found to be 0.32% by weight as Re metal. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 15.

Example 26 (Preparation of catalyst T)
MFI-type zeolite synthesized in the same manner as in Example 1 was 15 grams on the basis of absolute dryness (calculated from loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL Co., Al ₂ O ₃ content 75% by weight) the 33.3 g _(Al 2 _{O 3} of 25 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded product was extruded through a screen having a hole of 0.5 mmφ. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact, put it in an aqueous solution in which 4.94 grams of ammonium nitrate (Sigma Aldrich Co., Ltd.) and 2.3 grams of silver nitrate (Sigma Aldrich Co., Ltd.) are dissolved in 60 grams of distilled water. Treated with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed in 30 ml of a perrhenic acid aqueous solution (Rare Metals Co., Ltd.) containing 160 mg of Re at room temperature and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst S”. The silver content and sodium content in the catalyst were measured by atomic absorption spectrometry, and as a result, Ag was 1.7% by weight and Na was 0.1% by weight. The amount of rhenium supported in the catalyst was 0.67% by weight as Re metal as measured by ICP emission spectroscopy. The catalyst was pulverized and subjected to X-ray diffraction measurement. As a result, the crystal lattice spacing d value was 0.386 nm (2θ = 23.04 °) and the crystal lattice spacing d value was 0.196 nm (2θ = 46.18 °). The X-ray diffraction intensity ratio was 100: 15.

Examples 27-30
For each of the catalysts L to O, 7.5 g was charged in a reaction tube, and xylenes containing ethylbenzene were subjected to a gas phase reaction in the presence of hydrogen. The results are shown in Table 3.

  From Examples 27 to 30, it can be seen that the presence of an alkaline earth metal in the catalyst reduces xylene loss.

Examples 31-35
For each of the catalysts P to T, 2.5 g was charged in a reaction tube, and xylenes containing ethylbenzene were subjected to a gas phase reaction in the presence of hydrogen. The results are shown in Table 4.

  From Examples 31 to 35, it can be seen that the isomerization ratio to para-xylene decreases as the particle size of the catalyst increases. From Example 35, it can be seen that when silver ions are introduced, the isomerization rate to para-xylene is high.

Example 36 (Preparation of catalyst U)
MFI-type zeolite synthesized in the same manner as in Example 9 was 15 grams on the basis of absolute dryness (calculated from loss of ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL, Al ₂ O ₃ content 75 wt%) the 33.3 g _(Al 2 _{O 3} of 25 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a hole of 1.6 mmφ. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact, put it in an aqueous solution in which 3.30 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 1.77 grams of barium nitrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Processed with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed in 30 ml of a perrhenic acid aqueous solution (Rare Metals Co., Ltd.) containing 160 mg of Re at room temperature and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst U”. As a result of measuring the barium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.5% by weight as Ba and 0.1% by weight as Na. The amount of rhenium supported in the catalyst was 0.65% by weight as Re metal as measured by ICP emission spectroscopy. FIG. 13 shows the result of pulverizing this catalyst and measuring the X-ray diffraction. From FIG. 13, the X-ray diffraction intensity ratio between the crystal lattice spacing d value of 0.385 nm (2θ = 23.06 °) and the crystal lattice spacing d value of 0.195 nm (2θ = 46.44 °) is 100: 20. It was.

Example 37 (Preparation of catalyst V)
MFI-type zeolite synthesized in the same manner as in Example 9 was 15 grams on the basis of absolute dryness (calculated from loss of ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL, Al ₂ O ₃ content 75 wt%) the 33.3 g _(Al 2 _{O 3} of 25 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a hole of 1.6 mmφ. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact, 60 grams of distilled water with 3.30 grams of ammonium nitrate (Sigma Aldrich), 3.30 grams of barium nitrate (Sigma Aldrich), 2.3 grams of silver nitrate (Kirk). It was put into the dissolved aqueous solution and treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed in 30 ml of a perrhenic acid aqueous solution (Rare Metals Co., Ltd.) containing 160 mg of Re at room temperature and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Then, it baked in 540 degreeC for 2 hours in the air. This catalyst is hereinafter abbreviated as “catalyst V”. The barium content, silver content, and sodium content in the catalyst were measured by atomic absorption spectroscopy, and as a result, Ba was 1.0% by weight, Ag was 2.7% by weight, and Na was 0.1% by weight. The amount of rhenium supported in the catalyst was 0.68% by weight as Re metal as measured by ICP emission spectroscopy. As a result of pulverizing this catalyst and measuring X-ray diffraction, the X-ray diffraction intensity ratio of 0.384 nm (2θ = 23.12 °) and crystal lattice spacing d value 0.195 nm (2θ = 46.44 °) is 100 to 19.

Example 38 (Preparation of catalyst W)
MFI-type zeolite synthesized in the same manner as in Example X, 15 grams on the basis of absolute dryness (calculated from loss on ignition when calcined at 500 ° C. for 20 minutes), hydrous alumina (SASOL, Al ₂ O ₃ content 75% by weight) the 33.3 g _(Al 2 _{O 3} of 25 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as a six grams) was added and thoroughly mixed. Then, it put into 120 degreeC dryer and dried until it became clay-like water | moisture content. The kneaded material was extruded through a screen having a hole of 0.5 mmφ. The extruded product was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 20 grams of the baked compact and place it in an aqueous solution in which 1.65 grams of ammonium chloride (Sigma Aldrich Co., Ltd.) and 2.7 grams of calcium chloride dihydrate (Kirk Corp.) are dissolved in 60 grams of distilled water. Treated at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed with distilled water 5 times, and filtration was repeated. It was immersed in 30 ml of an aqueous solution of perrhenic acid (Rare Metal Co., Ltd.) containing 80 mg of Re at room temperature and left for 2 hours. Stir every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, hydrogen sulfide treatment was performed in a hydrogen sulfide stream at 250 ° C. for 2 hours. Thereafter, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter abbreviated as “catalyst S”. As a result of measuring the barium content and sodium content in the catalyst by atomic absorption spectrometry, it was 0.9% by weight as Ba and 0.2% by weight as Na. The amount of rhenium supported in the catalyst was measured by ICP emission spectroscopy and found to be 0.32% by weight as Re metal. As a result of pulverizing this catalyst and measuring X-ray diffraction, the X-ray diffraction intensity ratio of 0.384 nm (2θ = 23.12 °) and crystal lattice spacing d value 0.195 nm (2θ = 46.44 °) is 100 to 19.

Examples 39-41
For each of the catalysts U to W, 2.5 g was charged in a reaction tube, and xylenes containing ethylbenzene were subjected to a gas phase reaction in the presence of hydrogen. The results are shown in Table 5.

From Examples 39 to 41, even if the zeolite has a SiO ₂ / Al ₂ O ₃ molar ratio of 25 and an average crystallite size of 0.05 μm in the major axis and 0.05 μm in the minor axis, When barium ions and / or silver ions are present, W / F is 10 g-cat. Even under the condition of a small amount of catalyst such as hr / g-mol, xylene loss can be reduced and a high ethylbenzene conversion rate and a high para-xylene isomerization rate can be exhibited.

1 is an X-ray diffraction pattern of an MFI type zeolite obtained in Example 1. FIG. 1 is an FE-SEM observation diagram (magnification 10,000 times) of the MFI-type zeolite obtained in Example 1. FIG. 2 is an X-ray diffraction diagram of hydrous alumina used in Example 1. FIG. 2 is an X-ray diffraction pattern of catalyst A obtained in Example 1. FIG. 2 is an X-ray diffraction pattern of α-alumina used in Comparative Example 1. FIG. 2 is an X-ray diffraction diagram of catalyst B obtained in Comparative Example 1. FIG. 3 is an X-ray diffraction diagram of catalyst C obtained in Comparative Example 2. FIG. 3 is an X-ray diffraction diagram of catalyst D obtained in Example 2. FIG. 6 is an FE-SEM observation diagram (magnification: 10,000 times) of the MFI-type zeolite obtained in Example 5. FIG. FIG. 6 is an FE-SEM observation diagram (magnification 10,000 times) of the MFI-type zeolite obtained in Example 8. 4 is an FE-SEM observation diagram (magnification of 100,000 times) of the MFI-type zeolite obtained in Example 9. FIG. 4 is an X-ray diffraction pattern of a catalyst K obtained in Comparative Example 3. FIG. 2 is an X-ray diffraction diagram of a catalyst U obtained in Example 36. FIG.

Claims (11)

X-ray diffraction intensity ratio of crystal lattice spacing d value 0.386 ± 0.008 nm attributed to MFI-type zeolite and crystal lattice spacing d value 0.196 ± 0.002 nm attributed to alumina is from 100 to 7 to 100 pairs. A conversion catalyst for ethylbenzene-containing xylenes containing MFI-type zeolite and alumina, wherein the catalyst is 35. The catalyst containing 15 to 80 parts by weight of MFI type zeolite and 85 to 20 parts by weight of alumina is selected from 0.05 to 5% by weight of alkaline earth metal, 0 to 5% by weight of silver, rhenium, platinum and nickel. 2. The ethylbenzene-containing xylene conversion catalyst according to claim 1, further comprising 0.005 to 1.5 wt% of at least one kind. The catalyst containing 20 to 60 parts by weight of MFI zeolite and 80 to 40 parts by weight of alumina is selected from 0.05 to 5% by weight of alkaline earth metal, 0 to 5% by weight of silver, rhenium, platinum and nickel. 2. The ethylbenzene-containing xylene conversion catalyst according to claim 1, further comprising 0.005 to 1.5 wt% of at least one kind. The MFI-type zeolite has a major axis and a minor axis of crystallites of 0.7 to 2.5 microns and a silica / alumina molar ratio of 30 to 55, respectively. Conversion catalyst for xylenes containing ethylbenzene. 4. The ethylbenzene according to claim 1, wherein the MFI-type zeolite has a crystallite major axis and minor axis of 1 to 2.5 μm and a silica / alumina molar ratio of 35 to 45. 5. Conversion catalyst for xylenes. 6. The ethylbenzene-containing xylene conversion catalyst according to claim 4, wherein the alkaline earth metal is at least one selected from calcium, strontium, and barium. The MFI-type zeolite has a major axis and a minor axis of crystallites of 0.03 to 0.7 microns, and a silica / alumina molar ratio of 18 to 30. Conversion catalyst for xylenes containing ethylbenzene. 8. The ethylbenzene-containing xylene conversion catalyst according to claim 7, wherein the alkaline earth metal is at least one selected from strontium and barium. 9. The ethylbenzene-containing xylene conversion catalyst according to any one of claims 1 to 8, wherein the catalyst particles have a diameter of 0.2 to 2.0 millimeters. A conversion catalyst for ethylbenzene-containing xylenes obtained by treating the catalyst according to any one of claims 1 to 9 with hydrogen sulfide. A method for converting ethylbenzene-containing xylenes, wherein xylenes containing ethylbenzene are brought into contact with the conversion catalyst for ethylbenzene-containing xylenes according to any one of claims 1 to 10 in the presence of hydrogen.

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