JP2007001942A - Production method of para-xylene - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing p-xylene by regulating the concentration of the p-xylene in a mixture of xylene isomers so as to be not less than the equilibrium concentration when obtaining the xylene from a feedstock containing 9C aromatic hydrocarbons. <P>SOLUTION: The method for producing the p-xylene involves bringing the feedstock containing the 9C aromatic hydrocarbons into contact with a catalytic layer comprising the first catalytic layer having a catalyst including an acid-type zeolite constituted of 12- or more-membered oxygen ring and having pores, and the second catalytic layer having an acid-type zeolite catalyst requiring ≥1,000 min before reaching the amount (measuring condition: 120°C and 1.0 Torr o-xylene vapor pressure) of adsorbed o-xylene corresponding to 1/10 of the amount (measuring condition: 120°C, 1.5 Torr p-xylene vapor pressure, and 180 min absorption time) of the adsorbed p-xylene, and arranged therein in the presence of hydrogen in vapor phase. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing xylene having a high para-xylene concentration in producing xylene from a feedstock containing an aromatic hydrocarbon having 9 carbon atoms. Para-xylene is extremely important as a polyester raw material.

  Of the xylene isomers, para-xylene is currently the most important industrially. Para-xylene is a raw material for polyester used in synthetic fibers, PET bottles, films and the like, and so far its demand has been remarkably increased. This trend is expected to remain unchanged.

  However, at present, the amount of xylene obtained from the oil refining process cannot keep up with the rapidly increasing demand for para-xylene. Therefore, xylene is produced from an aromatic hydrocarbon source other than xylene. Specifically, a method for producing xylene and benzene by disproportionation reaction on a zeolite catalyst with toluene is disclosed (for example, see Patent Document 1). A method for obtaining xylene from a C9 alkyl aromatic hydrocarbon by a transalkylation reaction on a zeolite catalyst has been disclosed (for example, see Patent Document 2). In either method, the para-xylene concentration in the produced xylene isomer is an equilibrium concentration of about 24%. The thermodynamic equilibrium concentration of the xylene isomer is as follows.

  On the other hand, a method for selectively converting para-xylene in an xylene isomer to an equilibrium concentration or higher by reacting toluene on a specific zeolite catalyst has been disclosed (for example, see Patent Document 3). However, this process converts toluene to para-xylene using feedstock, and C9 alkyl aromatic hydrocarbons are not substantially converted to para-xylene.

  In general, however, transalkylation catalysts for converting aromatic hydrocarbons usually have different optimum reaction conditions depending on the catalyst. Therefore, conventionally, these catalysts are combined to form a catalyst layer in a common reaction system. No attempt was made to react.

In other words, in the case of using a feedstock containing C9 alkyl aromatic hydrocarbons, there has not yet been found a method for setting the para-xylene concentration in the xylene isomer mixture to be equal to or higher than the equilibrium concentration.
Japanese Patent Publication No. 47-46051 (Example 1) Patent Publication No. 11-70334 (Example 7) Patent Publication No. Sho 62-47854 (Example 3)

  The present invention provides a method for efficiently producing para-xylene by setting the para-xylene concentration in the xylene isomer mixture to be equal to or higher than the equilibrium concentration when xylene is obtained from a feedstock containing an aromatic hydrocarbon having 9 carbon atoms. The issue is to provide.

  In order to solve the above-mentioned problems, the present inventors have intensively studied. As a result, they have found that para-xylene can be efficiently produced by composing a catalyst layer by combining specific catalyst layers, and have reached the present invention.

  That is, the present invention is directed to “a catalyst containing a feedstock containing an aromatic hydrocarbon having 9 carbon atoms and an acid-type zeolite having pores composed of 12-membered oxygen rings or more in the first catalyst layer; More than 1000 minutes to reach the ortho-xylene adsorption amount corresponding to 1/10 of the para-xylene adsorption amount (measurement conditions: 120 ° C., para-xylene vapor pressure 1.5 torr, adsorption time 180 minutes) on the catalyst layer A method for producing para-xylene, which comprises contacting in a gas phase in the presence of hydrogen with a catalyst layer in which the required zeolite catalyst is disposed (measurement conditions: 120 ° C., ortho-xylene vapor pressure 1.0 torr). It is.

  According to the present invention, xylene, particularly para-xylene, which is increasing in industrial demand, can be obtained from a feedstock containing an aromatic hydrocarbon having 9 carbon atoms at a concentration higher than the thermodynamic equilibrium. Thus, para-xylene can be produced efficiently.

  Aromatic hydrocarbons having 9 carbon atoms include trimethylbenzene, ethyltoluene, propyl-benzene and the like. The feedstock containing these aromatic hydrocarbons is desorbed by hydrodealkylation reaction in the presence of hydrogen in the first catalyst layer, and at the same time, methyl groups are transmethylated to produce xylene and / or Xylene having a high para-xylene concentration by producing toluene and then selectively subjecting toluene to a transmethylation reaction in the second catalyst layer, in particular, by making the para-xylene concentration in the xylene isomer more than the equilibrium concentration. Can be obtained. One embodiment is to increase the amount of xylene produced by coexisting benzene, toluene, or aromatic hydrocarbons having 10 or more carbon atoms in the feedstock.

  In the present invention, such a feedstock is brought into contact with a catalyst containing acid-type zeolite having pores composed of 12-membered oxygen rings or more in the first catalyst layer in the gas phase in the presence of hydrogen, 1000 to reach the ortho-xylene adsorption amount corresponding to 1/10 of the para-xylene adsorption amount (measurement conditions: 120 ° C., para-xylene vapor pressure 1.5 torr, adsorption time 180 minutes) in the two catalyst layers. (Measuring conditions: 120 ° C., ortho-xylene vapor pressure 1.0 torr) It can be achieved by contacting with an acid type zeolite catalyst.

  As the zeolite having pores composed of 12-membered oxygen rings or more used in the first catalyst layer, a mordenite-type zeolite (for example, Example 1 on page 4-5 of JP-B-2-31006, JP-A No. Sho). Examples include 55-126529, page 11, example 11), beta-type zeolite (see, for example, Example 1 in column 8 of US Pat. No. 3,308,069), and the like. An example of the zeolite having 14-membered oxygen ring pores is CFI-type zeolite often referred to as CIT-5 (for example, see Example 5 in the pamphlet of International Publication No. 99/089161 column 36). .

  The reaction conditions for converting to toluene and / or xylene by hydrodealkylation reaction or transmethylation reaction using zeolite having pores composed of 12 or more oxygen rings as a catalyst are usually 420 ° C. or lower. In the transmethylation reaction using the second catalyst layer, which will be described later, the optimum condition usually exists above 420 ° C. Therefore, the first catalyst layer is controlled so as to function under the same reaction conditions as the second catalyst layer, that is, the optimum reaction condition is shifted to a high temperature by reducing the activity of the first catalyst layer, thereby optimizing the second catalyst layer. By adjusting to the reaction conditions, para-xylene can be obtained at a higher concentration. The following method is mentioned as a method for that.

  That is, in order for each catalyst used for the first catalyst layer and the second catalyst layer to function under the same reaction conditions, there are a method of adjusting by the amount of catalyst used and a method of controlling the performance of the catalyst itself by the catalyst preparation method. More preferably, the latter, that is, a method in which the catalyst performance is controlled by the catalyst preparation method. There are two methods for preparing the catalyst for allowing the first catalyst layer to function under the same reaction conditions as the second catalyst layer. One method is to control the solid acid sites in the zeolite contained in the catalyst used in the first catalyst layer, and the other method is to limit the content of zeolite contained in the catalyst. . That is, when the optimum reaction temperature is lower in the first catalyst layer than in the second catalyst layer, this means that the activity of the catalyst is high, and the solid acid point is reduced in order to reduce the activity, or included in the catalyst. By setting the content of zeolite to be low, the activity of the entire catalyst layer can be lowered. These methods may be used alone or in combination.

  The method for controlling the first solid acid point is performed as follows.

  Since synthetic zeolite is generally a powder, it is preferably molded for use. Examples of the molding method include a kneading / extrusion method, a rolling method, and a compression molding method, and the kneading / extrusion method is more preferable. In the kneading / extrusion method, inorganic binders such as alumina sol, alumina gel, bentonite and kaolin and surfactants such as sodium dodecylbenzenesulfonate, span and twin are added as molding aids to the synthetic zeolite powder as required. Kneaded. If necessary, a machine such as a kneader is used. Furthermore, depending on the metal added to the catalyst, a metal oxide such as alumina or titania is added at the time of molding the zeolite, thereby increasing the amount of the metal added to the catalyst or improving the dispersibility. 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 noodle-like 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. The noodle-like molded body extruded from the screen is preferably treated with a malmerizer to round off the corners. The molded body molded in this way is dried at 50 to 250 ° C. After drying, it is fired at 250 to 600 ° C., preferably 350 to 600 ° C., in order to improve the molding strength.

The molded body thus prepared is subjected to an 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.

Alkali metal, alkaline earth metal, and rare earth metal ions are used to control the solid acid point in a decreasing direction. Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ ions as alkali metal ions, Mg2 ⁺ , Ca2 ⁺ , Sr2 ⁺ , Ba2 ⁺ ions as alkaline earth metal ions, and La as rare earth metal ions ³⁺ and Ce ³⁺ ions. As these metal ions, chlorides, nitrates, sulfates and the like which are soluble in water are used. These ion exchange methods for introducing metal ions and ion exchange methods for introducing ammonium ions or direct hydrogen ions can be carried out simultaneously or individually. The ion exchange treatment is usually carried out with an aqueous solution by a batch method or a distribution method. The treatment temperature is usually from room temperature to 100 ° C. In the present invention, the preferred amount of metal ions present in the zeolite is preferably 10 to 80 equivalent percent, more preferably 20 to 60 equivalent percent of the zeolite exchange cation. The metal ion exchange rate can be easily determined from the amount of metal ions obtained by measuring the molded product before and after the ion exchange by a fluorescent X-ray analysis method, an atomic absorption method, an ICP analysis method, or the like.

  A second method in which the first catalyst layer functions under the same reaction conditions as the second catalyst layer is a method in which zeolite and an inorganic oxide are mixed, the zeolite content is reduced, and then solid acidity is imparted. Examples of inorganic oxides include alumina, titania, silica-alumina, bentonite, and kaolin. Specifically, the inorganic oxide is mixed in an amount of 100 to 2000 parts by weight, preferably 200 to 1500 parts by weight, based on 100 parts by weight of zeolite and molded. As the molding method, a kneading / extrusion method, a rolling method, a compression molding method, or the like is used, and the kneading / extrusion method is preferable. The molded body is dried at 50 to 250 ° C. After drying, in order to improve the molding strength, baking is performed at 250 to 600 ° C, preferably 350 to 600 ° C. The molded body thus prepared is subjected to ion exchange treatment to impart solid acidity. As a method for imparting solid acidity, an ion exchange treatment is performed with a compound containing ammonium ions, ammonium ions are introduced into the ion exchange sites of the zeolite, and then, converted into hydrogen ions by drying and firing, or directly. Although there is a method in which hydrogen ions are introduced into the ion exchange site of the zeolite with a compound containing an acid, the former method, that is, a method of performing an ion exchange treatment with a compound containing ammonium ions is preferred. Moreover, it is also one embodiment to introduce part of alkali metal ions, alkaline earth metal ions, and rare earth metal ions.

  The molded body used for the first catalyst layer subjected to the ion exchange treatment in this manner preferably carries a hydrogenation active metal. By allowing hydrogen to be present in the catalytic reaction system and supporting the hydrogenation active metal, it is possible to prevent deterioration of the catalyst with time. As the hydrogenation active metal, rhenium, platinum or the like is preferably used. In particular, rhenium is preferably used. Needless to say, the preferred loading varies depending on the metal to be carried. For example, in the case of rhenium, the preferred loading is 0.01 to 1.0% by weight, more preferably 0.05 to 0.5% by weight. In the case of platinum, it is 1-1000 ppm with respect to the whole catalyst, More preferably, it is 10-500 ppm.

  Increasing the amount of hydrogenated metal is not preferable because depending on the reaction conditions, nuclear hydrogenation or nuclear hydrogenolysis of the aromatic ring occurs. These metals are supported by immersing the catalyst in a solution containing at least one of rhenium and platinum, generally an aqueous solution. As the rhenium component, perrhenic acid, perrhenium ammonium and the like are used, and as the platinum component, chloroplatinic acid, ammonium chloroplatinate and the like are used.

  The catalyst thus prepared is dried at 50 to 250 ° C. for 30 minutes or longer, and calcined at 350 to 600 ° C. for 30 minutes or longer prior to use.

  In the second catalyst layer, toluene having a small minimum molecular diameter can selectively enter the zeolite pores, and benzene and xylene, particularly para- A zeolite catalyst with controlled pores is used so that xylene can be selectively produced. In the suspended pore-controlled zeolite catalyst, the isomers of meta-xylene, ortho-xylene and trimethylbenzene cannot enter the zeolite pores, but only pass through the catalyst surface. Table 2 shows the minimum molecular diameter of aromatic hydrocarbons. Shown in

A suspended zeolite catalyst with controlled pore size is used in the second catalyst layer. The zeolite suitable for the present invention is preferably a zeolite having pores composed of 10-membered oxygen rings. An example of zeolite having pores composed of 10-membered oxygen rings is MFI-type zeolite. 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, the MFI type zeolite preferred for the present invention has a crystallite having a major axis and a minor axis of 0.7 to 2.5 microns, and silica / alumina (hereinafter referred to as “SiO ₂ / Al ₂ O”). ₃ "(abbreviated as ₃ ") is a zeolite having a molar ratio of 30 to 55.

The suspended zeolite is a powder and must be molded. Molding is performed in the same manner as the catalyst used for the first catalyst layer. As a catalyst used in the second catalyst layer according to the present invention, it is necessary to further reduce the pore diameter of the zeolite while providing solid acidity. As described above, the provision of solid acidity can be achieved by introducing hydrogen ions or ammonium ions which are precursors of hydrogen ions and baking them. On the other hand, methods for narrowing the pore size of the zeolite include a method of contacting with a vapor of an organosilane compound (for example, tetramethoxysilane Si (OCH ₃ ) ₄ ), a metal alkoxide solution such as an alkaline earth metal (for example, ethoxybarium Ba It can be achieved by a method of impregnating (OC ₂ H ₅ ) ₂ ), a method of mixing an alkaline earth metal salt aqueous solution with zeolite, and firing it. Any of these methods is preferably used for the catalyst used in the second catalyst layer according to the present invention. However, from an industrial point of view, a method of mixing an alkaline earth metal salt aqueous solution with zeolite and calcining is most preferable. In this case, a method in which an alkaline earth metal salt aqueous solution is mixed in a system in which alumina is added to zeolite, kneaded well and fired is particularly preferably used. A preferred amount of alkaline earth metal is 0.5 to 6% by weight (metal equivalent) based on the catalyst. If it is less than 0.5% by weight, the pore diameter of the zeolite is not reduced, and if it exceeds 6% by weight, the catalytic activity is remarkably lowered. As the alkaline earth metal, barium is particularly preferable. Examples of barium salts include barium chloride, barium nitrate, and barium acetate.

  In any method, whether the catalyst is used in the present invention is determined as follows. The catalyst is previously calcined in air at 550 ° C. for 2 hours. Using this catalyst, the amount of para-xylene adsorbed is measured with time at 120 ° C. and para-xylene vapor pressure of 1.5 Torr. On the other hand, the adsorption amount of ortho-xylene is measured with time at 120 ° C. and ortho-xylene vapor pressure of 1.0 torr. The zeolite which is required for 1000 minutes or more to reach the ortho-xylene adsorption amount corresponding to 1/10 of the para-xylene equilibrium adsorption amount after the adsorption time of 180 minutes is the acid type zeolite catalyst used in the present invention.

  Moreover, the catalyst used for a 2nd catalyst layer carries | supports a hydrogenation active metal as needed. As a preferable hydrogenated active metal, rhenium, platinum or the like is preferably used. In particular, rhenium is preferably used.

  As described above, the catalyst prepared as described above constitutes a catalyst layer by arranging it in layers in the same reaction system. Specifically, the first catalyst layer may be filled in the reaction vessel in the form of a layer on the supply port side of the feedstock and the second catalyst layer on the reaction product discharge port side. Alternatively, the first catalyst layer and the second catalyst layer may be partitioned and filled with a metal mesh or the like.

The reaction in the present invention can be performed according to various conventionally known reaction operations. The reaction system is preferably a fixed bed reaction system and is used under the following reaction conditions. That is, the reaction operation temperature is 350 to 600 ° C, preferably 400 to 550 ° C. The reaction operation pressure is from atmospheric pressure to 10 MPa, preferably from 0.3 to 5 MPa. The weight space velocity (WHSV) representing the contact time of the reaction is 0.1 to 20 hr ⁻¹ , preferably 0.5 to 10 hr ⁻¹ . The ratio of hydrogen to feedstock oil is 0.5 to 10 molar ratio, preferably 1 to 5 molar ratio. More preferably, the feedstock oil is contacted with the catalyst in the gas phase.

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

(Synthesis of mordenite type zeolite)
Solid caustic soda (NaOH content 96.0% by weight, H ₂ O content 4.0% by weight, Kirk Corporation) 21.3 grams, tartaric acid powder (tartaric acid content 99.7% by weight, H ₂ O content 0.3% by weight) , Kirk Co., Ltd.) 21.3 grams was dissolved in 586.8 grams of distilled water. To this solution was added 29.2 grams of sodium aluminate solution (Al ₂ O ₃ content 18.5 wt%, NaOH content 26.1 wt%, H ₂ O content 55.4 wt%, Sumitomo Chemical Co., Ltd.) A uniform solution was obtained. Hydrous silicic acid (SiO ₂ content 91.6 wt%, Al ₂ O ₃ content 0.33 wt%, NaOH content 0.27 wt%, Nipsil VN-3, Nippon Silica Industry Co., Ltd.) 111.5 Grams were added slowly 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 30
OH ⁻ / SiO ₂ 0.5
A / Al ₂ O ₃ 2.5 (A: tartrate)
H ₂ O / SiO ₂ 20

  The reaction mixture was sealed in a 1 L autoclave and then reacted at 160 ° C. for 72 hours while stirring at 250 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 to be mordenite type zeolite.

After calcination of this mordenite-type zeolite in the presence of air at 500 ° C. for 2 hours, the composition was analyzed by atomic absorption method.
_{1.01Na 2 O · Al 2 O 3} · 18SiO 2
Met.

  As a result of FE-SEM observation at a magnification of 10,000, the crystallite size was mainly about 0.5 microns.

(Synthesis of CFI type zeolite)
69.8 grams of distilled water, 69.8 grams of 3% by weight lithium hydroxide aqueous solution (LiOH anhydrous primary reagent, Kishida Chemical Co., Ltd.), methylspartenium hydroxide (hereinafter referred to as “MeSPOH”) (MeSPOH solution concentration 1) .51mmol / g) was added and stirred solution 187.42 g, 5 wt% aqueous aluminum nitrate solution _{(Al (NO 3) 3 ·} 9H 2 O guaranteed reagent, Inc. Kirk) and ethylenediaminetetraacetic acid (hereinafter "EDTA" and 4.32 g) was added and stirred well for 15 minutes. Next, 18.57 grams of hydrous silicic acid (SiO ₂ content 91.6% by weight, Al ₂ O ₃ content 0.33% by weight, NaOH content 0.27% by weight, Nip Seal VN-3, Nippon Silica Industry Co., Ltd.) The mixture was added and stirred for 3 hours. The composition ratio (molar ratio) of this reaction mixture was as follows.
SiO ₂ / Al ₂ O ₃ 70
LiOH / SiO ₂ 0.31
MeSPAOH / SiO ₂ 1.0
EDTA / Al 1.83
H ₂ O / SiO ₂ 50

  The reaction mixture was sealed in a 500 ml autoclave and then reacted at 177 ° C. for 11.5 days with stirring at 300 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 CFI type zeolite.

The CFI-type zeolite was calcined in the presence of air at 550 ° C. for 2 hours, and the composition was analyzed by an atomic absorption method.
_{0.42Li 2 O · Al 2 O 3} · 70SiO 2
Met.

  As a result of FE-SEM observation at a magnification of 100,000, the crystallite size was a needle-like crystal mainly having a minor axis of about 0.06 microns and a major axis of about 0.3 microns.

(MFI type zeolite synthesis)
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% by weight, NaOH content 25.4% by weight, H ₂ O content 55.7% by weight, Daiso Co., Ltd.) was added to this solution. It was set as the 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 1 L 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 MFI type zeolite.

After calcining this MFI-type zeolite in the presence of air at 500 ° C. for 2 hours, the composition was analyzed by an atomic absorption method.
_{1.02Na 2 O · Al 2 O 3} · 37SiO 2
Met.

  As a result of FE-SEM observation at a magnification of 10,000, the crystallite size was about 1.1 microns for the minor axis and about 1.3 microns for the major axis.

Production of “Catalyst A” 20 grams of mordenite-type zeolite powder (calculated from the loss of ignition when calcined at 500 ° C. for 20 minutes), 40 grams of hydrous alumina (SASOL, 75% by weight of Al ₂ O ₃ ) _(Al 15 grams as 2 _{O 3),} alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 90 g (as _Al 2 _{O 3} 9.0 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 1.2 mmφ hole. The extrudate was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 30 grams of the baked molded body and put it in an aqueous solution in which 4.5 grams of ammonium chloride (Aldrich) and 4.5 grams of calcium chloride dihydrate (Wako Pure Chemical Industries) are dissolved in 90 ml of distilled water. The ion exchange treatment was performed at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed once with distilled water, and filtered. Again, place in an aqueous solution in which 4.5 grams of ammonium chloride and 4.5 grams of calcium chloride dihydrate are dissolved in 90 ml of distilled water, and perform ion exchange treatment with occasional stirring at 80 ° C. for 1 hour. Went. This operation was repeated a total of 5 times. After the ion exchange treatment, washing with distilled water and filtration were repeated 5 times. It was immersed at room temperature in 45 ml of an aqueous solution of perrhenic acid containing 120 milligrams of Re (Rare Metal Co., Ltd.) and stirred for 2 hours with stirring every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter referred to as “catalyst A”. The metal ion of the molded product before the ion exchange treatment was sodium ion, and as a result of measurement by atomic absorption method, it was 1.1% by weight as Na. On the other hand, the sodium and calcium concentrations in the catalyst A were measured by atomic absorption spectrometry and found to be 0.06% by weight as Na ^{+ and} 0.40% by weight as Ca ²⁺ . Na ions and Ca ions accounted for 47 equivalent% of the zeolite exchange cation sites. The amount of rhenium supported was 0.31% by weight as Re metal as measured by ICP emission spectrometry.

Production of “Catalyst B” 15 g of CFI-type zeolite powder on the basis of absolute dryness (calculated from loss of ignition when calcined at 550 ° C. for 20 minutes), 25 g of hydrous alumina (SASOL, Al ₂ O ₃ content 75% by weight) _(Al 2 _{O 3} of 15 grams), alumina sol _(Al 2 _{O 3} content of 10 wt%, Nissan Chemical Industries Ltd.) 60 g _(Al 2 _{O 3} as 6.0 g) 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 1.2 mmφ hole. The extrudate was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. Take 30 grams of the baked molded body and put it in an aqueous solution in which 4.5 grams of ammonium chloride (Aldrich) and 4.5 grams of magnesium chloride (Wako Pure Chemical Industries) are dissolved in 90 ml of distilled water. The ion exchange treatment was carried out with stirring for some time. After the treatment, the aqueous solution was removed, washed once with distilled water, and filtered. Again, it was put into an aqueous solution in which 4.5 grams of ammonium chloride and 4.5 grams of magnesium chloride were dissolved in 90 ml of distilled water, and subjected to ion exchange treatment with occasional stirring at 80 ° C. for 1 hour, followed by washing with water / filtration. This operation was repeated a total of 5 times. After the ion exchange treatment, washing with distilled water and filtration were repeated 5 times. It was immersed at room temperature in 45 ml of an aqueous solution of perrhenic acid containing 120 milligrams of Re (Rare Metal Co., Ltd.) and stirred for 2 hours with stirring every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter referred to as “catalyst B”. The number of ion exchange equivalents per gram of the pre-ion exchange molded product is 1.51 × 10 ⁻⁴ equivalents calculated from the CFI-type zeolite composition used. On the other hand, the lithium and magnesium concentrations in the catalyst B were measured by atomic absorption spectroscopy, and as a result, they were 0.003% by weight as Li ^{+ and} 0.033% by weight as Mg ²⁺ . Li ions and Mg ions accounted for 21 equivalent% of the zeolite exchange cation sites. As a result of measuring the amount of rhenium supported by ICP emission spectrometry, it was 0.28% by weight as Re metal.

Production of “Catalyst C” 10 g (100 parts by weight) of mordenite-type zeolite powder based on absolute drying, 120 g of hydrous alumina (SASOL, 75% by weight of Al ₂ O ₃ ) (90 g as Al ₂ O ₃ ) , 900 parts by weight), alumina sol (Nissan Chemical Industry Co., Ltd., Al ₂ O ₃ content 10% by weight) 150 g (15 g, 150 parts by weight as Al ₂ O ₃ ), and add water until it becomes clayy And kneaded. The kneaded product was extruded through a screen having a 1.2 mmφ hole. The extrudate was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. 30 grams of the fired molded body was taken, put into an aqueous solution in which 4.5 grams of ammonium chloride was dissolved in 90 ml of distilled water, and subjected to ion exchange treatment at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed once with distilled water, and filtered. Again, it was put into an aqueous solution in which 4.5 g of ammonium chloride was dissolved in 90 ml of distilled water, and subjected to ion exchange treatment with occasional stirring at 80 ° C. for 1 hour, followed by washing with water / filtration. This operation was repeated a total of 5 times. After the ion exchange treatment, washing with distilled water and filtration were repeated 5 times. It was immersed at room temperature in 45 ml of an aqueous solution of perrhenic acid containing 120 milligrams of Re (Rare Metal Co., Ltd.) and stirred for 2 hours with stirring every 30 minutes. Then, the liquid was cut off and dried at 120 ° C. overnight. After drying, it was baked in air at 540 ° C. for 2 hours. This catalyst is hereinafter referred to as “catalyst C”. As a result of measuring the sodium concentration in the catalyst C by the atomic absorption method, it was 0.02 wt% as Na ⁺ . Na ions accounted for 6 equivalent% of the zeolite exchange site. The amount of rhenium supported was 0.33% by weight as Re metal as measured by ICP emission spectrometry.

Production of “Catalyst D” 50 grams of MFI-type zeolite powder on the basis of absolute dryness (calculated from loss of ignition when calcined at 500 ° C. for 20 minutes), 16.74 grams of barium acetate (Aldrich Corporation) (9 grams as Ba) Then, 37.5 g of alumina sol (Al ₂ O ₃ content 10 wt%, Nissan Chemical Industries, Ltd.) (3.75 g as Al ₂ O ₃ ) was added and mixed well. 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 1.2 mmφ hole. The extrudate was dried at 120 ° C. overnight. Next, the temperature was gradually raised from 350 ° C. to 550 ° C., and baked at 550 ° C. for 20 hours. 30 grams of the baked molded body was taken, put into an aqueous solution in which 4.5 grams of ammonium chloride (Aldrich Co., Ltd.) was dissolved in 90 ml of distilled water, and subjected to ion exchange treatment at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed once with distilled water, and filtered. Again, it was put into an aqueous solution in which 4.5 g of ammonium chloride was dissolved in 90 ml of distilled water, and subjected to ion exchange treatment with occasional stirring at 80 ° C. for 1 hour, followed by washing with water / filtration. This operation was repeated a total of 5 times. After the ion exchange treatment, washing with distilled water and filtration were repeated 5 times. After drying at 120 ° C. overnight, baking was performed at 550 ° C. for 1 hour. This catalyst is hereinafter referred to as “catalyst D”. The amount of barium in the catalyst was 3.5% by weight as Ba as a result of measurement by fluorescent X-ray analysis.

  After the catalyst D was previously dried at 350 ° C. for 2 hours, the adsorption rate of para-xylene and ortho-xylene was measured. Adsorption measurement was performed by the Mac Bain method using a quartz spring. The measurement temperature was 120 ° C., the vapor pressure of para-xylene was 1.5 torr, and the measurement of ortho-xylene was 1.0 torr. The results are shown in FIG. Shown in The amount of para-xylene adsorbed after an adsorption time of 180 minutes was 5.0% by weight. The amount of ortho-xylene adsorbed was 0.3% by weight even after 3000 minutes.

Manufacture of “Catalyst E” A catalyst prepared in the same manner as “Catalyst D” except that the extrudate was calcined at 550 ° C. for 20 hours and changed to 550 ° C. for 3 hours. This is referred to as catalyst E ".

  After the catalyst E was previously dried at 350 ° C. for 2 hours, the adsorption rate of para-xylene and ortho-xylene was measured. Adsorption measurement was performed by the Mac Bain method using a quartz spring. The measurement temperature was 120 ° C., the vapor pressure of para-xylene was 1.5 torr, and the measurement of ortho-xylene was 1.0 torr. The amount of para-xylene adsorbed after 180 minutes of adsorption time was 6.0% by weight. The time required for the ortho-xylene adsorption amount to reach 0.60% by weight, which is 1/10 of the para-xylene adsorption amount, was 2600 minutes.

Production of “Catalyst” F 50 grams of MFI-type zeolite powder on an absolute dry basis, 75 grams of alumina sol (Al ₂ O ₃ content 10% by weight, Nissan Chemical Industries, Ltd.) (7.5 grams as Al ₂ O ₃ ) were added, Mix well. 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 1.2 mmφ hole. The extrudate was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. 30 grams of the baked molded body was taken, put into an aqueous solution in which 4.5 grams of ammonium chloride (Aldrich Co., Ltd.) was dissolved in 90 ml of distilled water, and subjected to ion exchange treatment at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed once with distilled water, and filtered. Again, it was put into an aqueous solution in which 4.5 g of ammonium chloride was dissolved in 90 ml of distilled water, and subjected to ion exchange treatment with occasional stirring at 80 ° C. for 1 hour, followed by washing with water / filtration. This operation was repeated a total of 5 times. After the ion exchange treatment, washing with distilled water and filtration were repeated 5 times. After drying at 120 ° C. overnight, baking was performed at 550 ° C. for 1 hour. This catalyst is hereinafter referred to as “catalyst F”.

  The catalyst F was sieved, 12-24 mesh was collected, dried at 350 ° C. for 2 hours, and then the adsorption rate of para-xylene and ortho-xylene was measured. Adsorption measurement was performed by the Mac Bain method using a quartz spring. The measurement temperature was 120 ° C., the vapor pressure of para-xylene was 1.5 torr, and the measurement of ortho-xylene was 1.0 torr. The result is shown in FIG. Shown in The amount of para-xylene adsorbed after an adsorption time of 180 minutes was 6.6% by weight. The time for the ortho-xylene adsorption amount to reach 0.66% by weight, which is 1/10 of the para-xylene adsorption amount, was within 10 minutes.

Production of “Catalyst G” 50 grams of MFI type zeolite powder on an absolute dry basis, 75 grams of alumina sol (Al ₂ O ₃ content 10% by weight, Nissan Chemical Industries, Ltd.) (7.5 grams as Al ₂ O ₃ ) were added, Mix well. 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 1.2 mmφ hole. The extrudate was dried at 120 ° C. overnight, then gradually heated from 350 ° C. to 540 ° C. and fired at 540 ° C. for 2 hours. 30 grams of the baked molded body was taken, put into an aqueous solution in which 4.5 grams of ammonium chloride (Aldrich Co., Ltd.) was dissolved in 90 ml of distilled water, and subjected to ion exchange treatment at 80 ° C. for 1 hour with occasional stirring. After the treatment, the aqueous solution was removed, washed once with distilled water, and filtered. Again, it was put into an aqueous solution in which 4.5 g of ammonium chloride was dissolved in 90 ml of distilled water, and subjected to ion exchange treatment with occasional stirring at 80 ° C. for 1 hour, followed by washing with water / filtration. This operation was repeated a total of 5 times. Then, it put into the aqueous solution which melt | dissolved 10 grams of barium nitrate (Aldrich Co., Ltd.) in 90 ml of distilled water, and the ion exchange process was performed, stirring occasionally at 80 degreeC for 1 hour. After the ion exchange treatment, washing with distilled water and filtration were repeated 5 times. After drying at 120 ° C. overnight, baking was performed at 550 ° C. for 1 hour. This catalyst is hereinafter referred to as “catalyst G”. The barium content of catalyst G was 2.1% by weight as Ba as a result of measurement by fluorescent X-ray analysis.

  The catalyst G was sieved, 12-24 mesh was collected, dried at 350 ° C. for 2 hours, and then the adsorption rate of para-xylene and ortho-xylene was measured. Adsorption measurement was performed by the Mac Bain method using a quartz spring. The measurement temperature was 120 ° C., the vapor pressure of para-xylene was 1.5 torr, and the measurement of ortho-xylene was 1.0 torr. The results are shown in FIG. Shown in The amount of para-xylene adsorbed after 180 minutes of adsorption time was 6.5% by weight. The time for the ortho-xylene adsorption amount to reach 0.65% by weight, which is 1/10 of the para-xylene adsorption amount, was 33 minutes.

Example 1
The composition shown in Table 3 is supplied from the supply port on the side where the first catalyst layer is arranged in a layer of 3.0 grams of catalyst A as the first catalyst layer and 5.0 grams of catalyst D as the second catalyst layer. Was fed and reacted in the presence of hydrogen. The results are shown in Table 3. Shown in In addition, the composition of the feedstock and the reaction product was analyzed by a gas chromatograph with an FID detector.

Example 2
The composition shown in Table 3 is supplied from a supply port on the side where 5.0 g of catalyst A is packed as a first catalyst layer and 3.0 g of catalyst E is packed as a second catalyst layer in a reaction tube. Was fed and reacted in the presence of hydrogen. The results are shown in Table 3. Shown in

Comparative Example 1
The composition shown in Table 3 is supplied from the supply port on the side where the first catalyst layer is placed in a reaction tube filled with 5.0 g of catalyst A as the first catalyst layer and 3.0 g of catalyst F as the second catalyst layer. Was fed and reacted in the presence of hydrogen. The results are shown in Table 3. Shown in

Comparative Example 2
The reaction tube was filled with 8 grams of catalyst A and reacted in the presence of hydrogen. The results are shown in Table 3. Shown in

Comparative Example 3
The reaction tube was filled with 8 grams of catalyst D and reacted in the presence of hydrogen. The results are shown in Table 3. Shown in

  Table 3. As is clear from the above, a catalyst containing mordenite-type zeolite having pores consisting of 12-membered oxygen rings is used for the first catalyst layer, pores consisting of 10-membered oxygen rings are used for the second catalyst layer, and para- More than 1000 minutes are required to reach the ortho-xylene adsorption amount corresponding to 1/10 of the xylene adsorption amount (measurement conditions: 120 ° C., para-xylene vapor pressure 1.5 torr, adsorption time 180 minutes) (measurement (Condition: 120 ° C., ortho-xylene vapor pressure 1.0 torr) By using an MFI type zeolite catalyst, the xylene yield is high and the para-xylene concentration is high from the feedstock containing aromatic hydrocarbons having 9 carbon atoms. It can be seen that products higher than the equilibrium concentration can be obtained.

Example 3
The reaction tube was filled with 3.0 g of catalyst B as the first catalyst layer and 5.0 g of catalyst D as the second catalyst layer, and reacted in the same manner as in Example 1. The yield of xylene obtained was 36.91% by weight, and the para-xylene concentration in xylene was 29.33%.

Example 4
The reaction tube was filled with 3.0 g of catalyst C as the first catalyst layer and 5.0 g of catalyst D as the second catalyst layer, and the reaction was carried out in the same manner as in Example 1. The yield of xylene obtained was 36.13% by weight, and the para-xylene concentration in xylene was 28.68%. The Na ion of the catalyst C was 6 equivalent% of the zeolite exchange site. However, since the catalyst C is composed of 1050 parts by weight of the inorganic oxide with respect to 100 parts by weight of the zeolite, the xylene yield is high and the paraffin is high. It can be seen that products with xylene concentrations higher than the equilibrium concentration can be obtained.

Comparative Example 4
The reaction tube was filled with 3.0 g of catalyst A as the first catalyst layer and 5.0 g of catalyst G as the second catalyst layer, and reacted in the same manner as in Example 1. The yield of xylene obtained was 35.61% by weight, and the concentration of para-xylene in xylene was 24.03%.

FIG. 3 is a diagram showing adsorption of para-xylene and ortho-xylene at 120 ° C. by catalyst D. FIG. 3 is a diagram showing adsorption of para-xylene and ortho-xylene at 120 ° C. by catalyst F. FIG. 4 is a graph showing adsorption of para-xylene and ortho-xylene at 120 ° C. by catalyst G.

Claims (13)

A feedstock containing aromatic hydrocarbons having 9 carbon atoms, a catalyst containing acid-type zeolite having pores composed of 12-membered oxygen rings or more in the first catalyst layer, and para-xylene in the second catalyst layer It takes 1000 minutes or more to reach the ortho-xylene adsorption amount corresponding to 1/10 of the adsorption amount (measurement conditions: 120 ° C., para-xylene vapor pressure 1.5 torr, adsorption time 180 minutes) (measurement conditions : 120 ° C., ortho-xylene vapor pressure 1.0 torr) A method for producing para-xylene, comprising contacting a catalyst layer in which an acid-type zeolite catalyst is disposed in the gas phase in the presence of hydrogen. The para-xylene according to claim 1, wherein the acid type zeolite having pores composed of 12-membered oxygen rings or more is at least one of mordenite type zeolite, beta type zeolite and CFI type zeolite. Manufacturing method. 10 to 80 equivalent% of the exchange cation sites of the acid type zeolite having pores composed of 12-membered oxygen rings or more are at least one metal ion of alkali metal ions, alkaline earth metal ions, and rare earth metal ions. The method for producing para-xylene according to any one of claims 1 and 2. 20 to 60 equivalent% of the exchange cation sites of the acid-type zeolite having pores composed of 12-membered oxygen rings or more are at least one metal ion of alkali metal ions, alkaline earth metal ions, and rare earth metal ions. The method for producing para-xylene according to any one of claims 1 and 2. The catalyst containing acid-type zeolite having pores composed of 12-membered oxygen rings or more is characterized in that the inorganic oxide is composed of 100 parts by weight to 2000 parts by weight with respect to 100 parts by weight of zeolite. The method for producing para-xylene according to any one of claims 1 and 2. The catalyst containing acid type zeolite having pores composed of 12-membered oxygen rings or more is characterized in that the inorganic oxide is composed of 200 to 1500 parts by weight with respect to 100 parts by weight of zeolite. The method for producing para-xylene according to any one of claims 1 and 2. The method for producing para-xylene according to any one of claims 5 and 6, wherein the inorganic oxide is at least one of alumina, titania, silica-alumina, bentonite and kaolin. It takes 1000 minutes or more to reach the ortho-xylene adsorption amount corresponding to 1/10 of the para-xylene adsorption amount (measurement conditions: 120 ° C., para-xylene vapor pressure 1.5 torr, adsorption time 180 minutes). (Measurement conditions: 120 ° C., ortho-xylene vapor pressure 1.0 torr) The acid type zeolite catalyst is an acid type zeolite having pores composed of 10-membered oxygen rings. A process for producing para-xylene according to any one of the preceding claims. 9. The method for producing para-xylene according to claim 8, wherein the acid type zeolite having pores composed of 10-membered oxygen rings is MFI type zeolite. 10. The production of para-xylene according to claim 9, wherein the MFI-type zeolite has a crystallite major axis and minor axis of 0.7 to 2.5 microns and a silica / alumina molar ratio of 30 to 55. Method. 11. The catalyst according to claim 8, wherein the catalyst containing acid type zeolite having pores composed of 10-membered oxygen rings contains 0.5 to 6% by weight (in metal equivalent) of an alkaline earth metal. A process for producing para-xylene according to any one of the preceding claims. 12. The method for producing para-xylene according to claim 11, wherein the alkaline earth metal is barium. The method for producing para-xylene according to any one of claims 1 to 12, wherein the catalyst containing an acid-type zeolite contains one of rhenium and platinum.

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