JPS58210856A - Catalyst composition and isomerizing method of xylenes - Google Patents

Abstract

PURPOSE:To isomerize xylenes in a high isomerization yield, by bringing a raw material mixture contg. xylene isomer into vapor contact with a platinum modified catalyst compsn. contg. crystalline alumina silicate zeolite subjected to ion exhanging with Be, Sr or Ba. CONSTITUTION:The crystalline alumino silicate zeolite expressed by the formula I (the formula is expressed in the form of oxide in an anhydrous state. M; >=1 kind of cations among Be, Sr and Mg, N; >=1 kind of cations of valency (n) except alkaline earth metals, x; 0.1-1, y; 15-200) and platinum of the under- mentioned atm. are used as the essential active components of this catalyst compsn.: The amt. corresponding to 1-2,000 R expressed by the formula II (m1, m2, m3, m4 are respectively the mol. wts. of MO, N2/nO, Al2O3, SiO2 of the formula I , m; the atomic weight of platinum, W: weight% of platinum based on the weight of the above-described zeolite). This catalyst compsn. is formulated to provide 0.1-0.9 1, 3, 5-trimethyl benzene adsorptivity and >=60 ethyl benzene/xylene reaction selectivity.

Description

[Detailed description of the invention]

The present invention relates to a novel crystalline aluminosilicate zeolite-containing catalyst composition and a method for isomerizing xylenes using the same as a catalyst. Furthermore, the present invention provides a novel catalyst composition containing a crystalline aluminosilicate zeolite ion-exchanged with at least one member selected from the group of beryllium, strontium, and barium and modified with platinum, and a novel catalyst composition containing the crystalline aluminosilicate zeolite ion-exchanged with at least one member selected from the group of beryllium, strontium, and barium, and a novel catalyst composition modified with platinum. This invention relates to a method for isomerizing xylenes, which is used as a catalyst in the isomerization of xylenes. In this specification, unless otherwise specified, crystalline aluminosilicate zeolite will be abbreviated and simply referred to as "zeolite 1." Zeolites, both natural and synthetic, contain cations such as Na, K, or hydrogen ions. Contains

[2. It has a three-dimensional network structure mainly composed of 5ift and AtO4, and is characterized by a highly arranged regular tetrahedral structure in which S1 atoms and At atoms are cross-linked through oxygen atoms. It is. This zeolite has many pores of uniform size, and is used as a molecular node, and is also used as a catalyst or collateral in various chemical synthesis fields. In particular, synthetic zeolites are extremely homogeneous, highly pure, and have excellent properties. Therefore, many synthetic zeolites and methods for producing the same have been proposed. For example, so-called silica-rich zeolites with a molar ratio of 5iOt/Am03 of at least 10 have high stability and unique acidity, and are useful for example in selective adsorption, cranking, and hydrocranking. It has high activity as a catalyst for hydrocarbon conversion such as isomerization and alkylation. Many zeolites with high IJ power content have been proposed, mainly ZSM-based O zeolites.In particular, improvements and development of zeolite-containing catalysts used in xylenes isomerization methods and improvements in isomerization conditions are needed. The focus of research has been placed on these issues, and many proposals have been made regarding these issues. In other words, methods for changing the shape and structure of the zeolite catalyst itself: methods for modifying the zeolite catalyst by subjecting it to physical treatment, such as heat treatment; methods for chemically modifying the zeolite catalyst by adding various components; A lot of research has been done. For example, a method for treating Y-type zeolite with heated steam to improve catalyst activity and stabilization (U.S. Pat. No. 388
7630), Offretit
e) a method of improving the decomposition activity of ethylbenzene by adding M6os'frffi to the zeolite (see U.S. Pat. No. 3,848,009), a method of lowering and stabilizing the activity of zeolite by setting the 510x/Am03 molar ratio to 500 or more (JP-A-56
43219), a method of weakening the acidic point of the catalyst by continuously introducing basic nitrogen into the feed (Japanese Patent Laid-Open No. 5
4-19921). However, some of the xylene isomerization catalysts proposed so far have (a) excellent activity for xylene isomerization reactions and (0) undesirable side reactions (e.g. nuclear hydrogenation of benzene rings, hydrogenolysis). , demethylation, special disproportionation, transalkylation reactions, etc.) are contradictory as catalysts. (a) and (lr) 2
It is almost impossible to find anything that fully satisfies both conditions at the same time. In particular, when isomerizing a xylene isomer mixture containing ethylbenzene, it is desirable to de-ethylate ethylbenzene together with the isomerization reaction of xylenes, and several methods have been proposed for this purpose. For example, the above-described method is disclosed in US Pat. No. 4,098,836 and US Pat.
No. 28, No. 4152363 However, in the conventionally proposed method, in addition to the main reactions of xylene isomerization and ethylbenzene deethylation reaction, hydrogenation of the benzene ring is carried out. Undesirable side reactions such as xylene disproportionation and transalkylation of xylenes and ethylbenzene occur, and losses of xylenes are inevitable. For example, the three U.S. patents described above disclose a method for isomerizing a xylene isomer mixture containing ethylbenzene using a ZSM series zeolite modified with a platinum group metal such as nickel or platinum. In the case of a nickel-modified 28M-type zeolite catalyst (with a Ni content of 2 weight coefficients or more), the demethylation reaction of xylene can be reduced under severe reaction conditions due to the conversion rate of ethylbenzene. xylene loss increases. Therefore, it has been considered advantageous industrially to use ZBM-type zeolite catalysts modified with platinum group metals, which have less demethylation reaction. However, for example, ZSM-type zeolites modified with platinum, Platinum has excellent isomerization properties for xylenes and the ability to selectively deethylate the ethyl group of ethylbenzene, but on the other hand, platinum itself has hydrogenation activity on the benzene ring and is not susceptible to hydrogenation reactions. This occurs more significantly as the temperature decreases from thermodynamic equilibrium, and therefore the production of 7-tene compounds increases. As a result, xylene loss increases, and ZBM-type zeolite catalysts modified with platinum are industrially limited to 800"F.
It was necessary to use it at a high temperature of (427°C) or higher. Furthermore, the temperature required for the isomerization reaction depends on the space velocity;
In general, a temperature of about 300 to 320°C is sufficient; higher temperatures do not improve isomerization, but rather significantly inhibit undesirable reactions such as disproportionation and trans-alkylation, which are intermolecular rearrangement reactions involving xylene. In order to avoid such undesirable reactions as much as possible, the space velocity based on the zeolite catalyst is increased and the optimum temperature for isomerization is changed from the conventional method. A method has also been proposed in which deethylation is promoted while increasing the xylene content and suppressing xylene loss caused by disproportionation (U.S. Pat. No. 4,152,363).
(see issue). However, it is difficult to maintain the ID isomerization rate at a high level of 7B using this method, and the high temperature and high space velocity also lead to significant deterioration of catalyst activity, which is a major industrial drawback. . Therefore, the main object of the present invention is to prepare platinum-containing 2
The object of the present invention is to provide a new and improved method for isomerizing xylenes, which does not have the above-mentioned drawbacks that occur when xylenes are isomerized using an 8M zeolite catalyst. One object of the present invention is to maintain the excellent xylene isomerization ability and selective deethylation ability of the 28M-based zeolite catalyst containing platinum while eliminating the methyl group, which is the drawback of the catalyst. By providing a new and improved platinum-containing zsM-based zeolite catalyst assembly in which intermolecular rearrangement reactions, that is, disproportionation reactions of xylene and transalkylation reactions of xylene and ethylbenzene, are significantly suppressed. be. Other objects and advantages of the present invention will become clear from the vivid description given below.5 In order to achieve these objects, the present inventors have made extensive research into the characteristics of zeolite catalysts and their improvement. , beryllium to crystalline aluminosilicate zeolite by ion exchange method. The present invention was achieved based on the finding that a catalyst composition containing at least one member selected from the group of strontium and barium and containing platinum in the zeolite-containing catalyst composition is extremely effective. That is, according to the present invention, (1) General formula (I) xMO-(1-X)N10-jktzOm-7810t
...” ” (1) 11, yFits ~ 200
It is. The molecular weight of the crystalline aluminosilicate zeolite represented by 2 and each unit represented by the following formula ([1) ;, jim is the atomic weight of platinum, and W is the weight of the crystalline aluminosilicate zeolite. It is the weight percent of platinum with □i as the reference, and %"1F is the same as 1 in formula (1).
Contains platinum as the main active ingredient in an amount corresponding to R expressed by 7 from 1 to 2000, (2)
1,3,5-)limethylbenzene adsorption rate (RA) is in the range of 0.1 to 0.9, (3) (ethylbenzene/xylene) reaction 4 selectivity (RB) is at least 60, and an isomerization of xylenes, characterized in that the catalyst composition is brought into contact with a raw material mixture containing xylene isomers, at least one of which has a thermodynamic equilibrium concentration or less, in a gas phase. A method is provided. The present invention will be explained in more detail below. The novel catalyst composition of the present invention is such that a part or most of the total cation sites of the crystalline aluminosilicate zeolite contained therein are occupied by at least one cation of beryllium, strontium, and barium, and It is characterized by containing platinum in an amount within a certain range relative to the amount of cations. That is, the catalyst composition of the present invention includes (a) a zeolite into which at least one cation selected from the group of beryllium, strontium, and barium is introduced into the cation site);
, (b) platinum in an amount within a certain range relative to the amount of wrinkled cations, and (e) a carrier.The crystalline aluminosilicate zeolite serving as the pace of the catalyst used in the present invention may contain cations. The site mainly contains hydrogen ion precursors such as hydrogen ions or ammonium ions, and the silica/alumina molar ratio is 15 to 20.
0, preferably in the range 30 to 100, i.e., in the present invention Tokoruma high silica-containing zeolite, which has a relatively high content of silica to alumina, is used as the catalyst base. do. Many zeolites have been proposed that have a relatively high silica content compared to alumina, and the silica/alumina molar ratio is 200.
High-silica-containing zeolites with extremely high silica contents of up to 0 are also known, but in the present invention, the silica/alumina ratio is relatively low among high-silica-containing zeolites, and therefore the acid activity derived from the alumina component is It is characterized by the use of a relatively high degree of strength. In the present invention, any known high silica-containing zeolite can be used as long as the silica/alumina molar ratio falls within the above range. Representative examples of crystalline aluminosilicate, ie zeolite, as a catalyst base that can be used in the present invention include:
For example, Mobil Oil Corporation (Mobn
Oll Corporation, New York
ic. Various 28M zeolites developed by N., Y., USA) and Imperial Chemical Industries (
Industrial Chemical Engineering - ;ry L
Founded by the present inventors as zeta-based zeolite or high-silica-based zeolite developed by TD, UK),
The already proposed TP-1 zeolite (4I Kaisho 54-1
37500), among which the former ZS
M-type zeolites are preferred. Examples of ZBM-based zeolites include ZBM-5 (see US Pat. No. 3,702,886), 28M-11 (
(see U.S. Patent No. 3,709,979), ZSM-1
2 (see U.S. Pat. No. 3,832,449), ZSM
-35 (see US Pat. No. 4,016,245),
28M-as (see U.S. Pat. No. 4,046,859), etc. Zeta-based zeolites include Zeta 1 (see Japanese Patent Application Laid-open No. 51-67299) and Zeta 3 (see Japanese Patent Application Publication No. 51-67298). (see official bulletin). As the catalyst base in the present invention, among the above-mentioned zeolites, 28M-5, ZBM-11, 28M-12,
28M-35, ZEIM-38 are preferred, 4IK
It has been found that excellent effects are achieved using ZSM-5m zeolite. These zeolites are generally obtained in a form containing an alkali metal at the cation site immediately after their synthesis. In the present invention, when such zeolite is ion-exchanged by a conventional method, part or most of the cation sites are beryllium due to K. It is occupied by at least one kind of cation of strontium and barium, and the remaining cation sites are occupied by at least 411 kinds of cations selected from hydrogen ions, ammonium ions which are hydrogen precursors, or metal cations excluding alkaline earth metals. The composition is represented by the above general formula (1) in the form of an oxide in an anhydrous state. In the formula (1), X is an indicator of the amount of at least one cation of beryllium, strontium, and barium bonded to the zeolite, and (1-*) is an indicator of the amount of at least one cation of beryllium, strontium, and barium bonded to the zeolite, and (1-*) is an indicator of the amount of at least one cation of beryllium, strontium, and barium bonded to the zeolite; It is an indicator of the amount of cations. Zeolite, that is, crystalline aluminosilicate, is basically composed of a combination of silica tetrahedron and alumina tetrahedron, and the charge of this alumina tetrahedron is 1 1 1. There are cations in the crystal. It is thought that it has a neutralized structure due to its presence. Therefore, theoretically, the amount of cation is equivalent to the amount of alumina in moles, and the above formula (1) represents such a state. However, in reality, zeolite in its synthesized state contains cation precursors that cannot be removed by normal washing, and analysis data of synthesized zeolite suggests that the amount of cations in alumina In many cases, the amount exceeds an equimolar amount. However, such excess cationic precursors (e.g. organic ammonium compounds) are typically removed from the zeolite's crystal structure by exposing them to an oxygen atmosphere at elevated temperatures, e.g. 300° C. or higher, during the preparation of the catalyst composition. can be removed. Thus, the zeolite in the catalyst composition according to the invention is
This means that the amount of cations is substantially equimolar to that of alumina, and the above formula (1) represents such a state. The amount of at least one cation selected from the group of beryllium, strontium, and hybarium that is introduced into the cation site by ion exchange is X in the above formula (1).
is in the range of 0.1 to 1, preferably 0
．． It is desirable that the value of X is in the range of 3 to 0.8. If the value of X is smaller than 0.1, the effects of the present invention described later cannot be obtained, and if the value of The xylene isomerization reaction, which is the main reaction in the present invention, also tends to be suppressed. Further, y, which is an index of silica content, is preferably in the range of 15 to 200, preferably 30 to 100, in order to achieve the effects of the present invention. Furthermore, N in the formula (I) is a hydrogen ion or an ammonium ion which is a hydrogen ion precursor,
It is particularly suitable as an ion that exhibits isomerization activity. Thus, the catalyst composition of the present invention comprises a zeolite represented by the formula (1) which has been ion-exchanged with at least 41 types of beryllium, strontium, and barium as one component at an exchange rate within a certain range. The amount of R represented by the formula
000 of platinum. ZSM type zeolite catalysts modified only with platinum have been proposed. However, although the catalyst has excellent ability to isomerize the vynones and selectively deethylate ethyl groups of ethylbenzene, platinum itself The addition activity is high, and the hydrogenation reaction occurs more significantly as the temperature decreases due to thermodynamic equilibrium, resulting in increased production of naphthenes and loss of xylenes. Therefore, industrial use of ZSM type zeolite modified only with platinum requires a reaction under high temperature conditions, but under such harsh conditions, although the formation of naphthenes is suppressed, xylene is involved. The disproportionation and transalkyl reactions will be significantly accelerated and the loss of xylenes will be increased rather than the low temperature reaction. Therefore, in the catalyst composition of the present invention, a part or most of the cation sites in the zeolite are occupied by at least 411 species of beryllium, strontium, and barium, and as a result, the hydrogenation reaction to benzene rings is suppressed. Even when the reaction temperature is raised, the undesirable reactions such as the intermolecular rearrangement of methyl groups as described above can be suppressed to a significantly low level! #It's mold. Here, in the present invention, the preferable amount of platinum contained in the catalyst composition can be determined in relation to the ion exchange rate of at least one of the zeolite components beryllium, strontium, and barium. For the purposes of the present invention, the amount of platinum in the catalyst composition may be sufficient to sufficiently promote the deethyl reaction. However, if the ion exchange rate (due to at least one of beryllium, -strontium, and barium) is low, reaction conditions at low temperatures are selected to suppress the disproportionation reaction and trans-alkyl reaction involving xylene. On the other hand, due to constraints on the hydrogenation reaction of the benzene ring, a low platinum amount is required. In addition, if ion exchange does not occur, it is preferable to select reaction conditions at a higher temperature in order to maintain isomerization activity, etc. At that time, carbonaceous deposits on the catalyst Platinum with a slightly higher platinum content is desired for the purpose of suppressing the reaction and stabilizing the reaction over a long period of time. Thus, the preferred amount of platinum in the catalyst composition is correlated with the amount of beryllium, strontium, and barium introduced into the cation sites of the zeolite, and R defined by the above formula value is preferably in the range of 1 to 2,000. 10-1,
Selected in the range of 000. An R of less than 1 in the catalyst composition indicates a high platinum content, and as a result, excessively harsh reaction conditions are required to suppress the hydrogenation reaction. On the other hand, when R exceeds 2,000, the platinum content decreases, and as a result, the deethyl activity, which is an important characteristic of the skeleton catalyst composition, decreases. The catalyst composition further comprises 1,3. s -) Q It is characterized by the characteristic values of methylbenzene adsorption rate (RA) and (ethylbenzene/xylene) reaction selectivity (RB). That is, the 1.3.5-trimethylbenzene adsorption amount (RA) of the catalyst composition is measured by the method described below, and in the catalyst composition of the present invention, the adsorption amount (RA) of 1.3.5-trimethylbenzene is 0.1 to 0.
It is preferably in the range of 9. This adsorption* (RA) is determined by measuring the amount of 1,3,5-trimethylbenzene adsorbed after a certain period of time, and the larger this value, the faster the rate of molecular diffusion into the pores. It serves as an indicator to show the In the present invention, it is preferable that the adsorption rate (RA) be small to some extent, but extremely small RA tends to suppress the diffusion of any molecules, so RA = 0.2 to OJ is more preferable. This is considered to be within the range. Mata (ethylbenzene/xylene) reaction selectivity (RB)
is measured by the method described below, and represents the ratio of the reaction activities of ethylbenzene and xylene in the pores of the nuclear catalyst composition, and is the so-called proton-exchanged
For type 28M-5, it is usually 10 to 15, and for catalyst compositions containing platinum in addition to the zeolite, it is as high as 5.
However, in the catalyst composition used in the present invention, the RB is at least 460. It is preferably 80, which indicates that #iRB is preferably within such a range in the xylene isomerization reaction of a raw material composition containing ethylbenzene. The above 1,3.5-)limethylbenzene absorption jlf'
! -(RA) and U (ethylbenzene/xylene) reaction selectivity (RB) measurement method will be explained in detail. a) 1,3.5-)limethylbenzene adsorption rate (R
Measurement method of A) The RA is expressed as the ratio of the amount of 1.3.5-trimethylbenzene adsorbed by the catalyst composition to the amount of 1.3.5-trimethylbenzene adsorbed by the reference zeolite after a certain adsorption time. determined. The standard zeolite used is the so-called H-type Z8M-5, which is based on alumina and has protons occupying 90 or more, preferably 495% or more of the cation sites. 1 per unit weight of zeolite for the reference zeolite or the catalyst composition.
3.5- The amount of trimethylbenzene adsorbed is 4 in an electric furnace.
A fixed amount of zeolite or catalyst composition calcined at 50°C for 8 hours was weighed, and then heated at 25°C and 30±5wmH9
．． 3.5-) maintaining said weighed zeolite or catalyst composition in a saturated gas atmosphere of trimethylbenzene for a period of less than 20 minutes; Composition 2
After holding at 5°C and 30±5ymH9 for the same time as above, it is weighed, and the measurement can be made from the difference in weight before and after adsorption. The adsorption amount of the reference zeolite (VO
) and the adsorption amount (Vs) of the catalyst composition, RA is V
It is obtained as s/V. Here, if the adsorption time is longer than 20 minutes, regardless of the type and amount of cations present in the zeolite structure, 1,3.5-)IJ methylbenzene will sufficiently diffuse, and the adsorption amount will increase to FiE type-Z8M 5 and No significant differences may be observed between catalyst compositions. That is, it appears that the type or amount of cation controls the diffusion rate of adsorbed molecules into the pores. Therefore, the preferred adsorption time for measuring RA is 2
A time period of less than 0 minutes, more preferably less than 10 minutes, is used. b) (ethylbenzene/xylene) reaction R resistance (R
Measurement method of B) A catalyst composition containing 50 weight percent T-alumina and molded into 10 to 20 meshes in a benot shape in an electric furnace at 450°C for 8 hours, then a certain weight of the catalyst composition was transferred to a fixed bed. The reactor was charged with an aromatic hydrocarbon composition of ethylbenzene/xylene-15785 (by weight ratio) under -atmospheric pressure and fed at a rate of WH8V = 4HR7' (based on total weight), and hydrogen/ Hydrocarbon-1,71
#j is determined by flowing hydrogen. The catalyst bed temperature was set at 811 so that the ethylbenzene conversion rate, which will be described later, was 30%. The RB is calculated as the ratio of the ethylbenzene conversion to the xylene conversion, and the above WH8V is the ethylbenzene conversion. The xylene conversion rate and RB will be the values defined by the following formula: ethylbenzene conversion IE(a) - xylene conversion rate - Thus, in the present invention, at least one of beryllium, strontium, and barium is used to obtain an exchange rate within a certain range. A catalyst composition containing zeolite ion-exchanged in While exhibiting the effect of suppressing the intermolecular rearrangement reaction of methyl groups, that is, the disproportionation reaction of xylene and the transalkyl reaction between xylene and ethylbenzene, without substantially causing the hydrogenation reaction. , which promptly promotes the isomerization reaction of xylene and the deethylation reaction of ethylbenzene. Namely, beryllium. By performing ion exchange with at least one type of 4b of strontium and barium, adjusting the pore diameter within the pores in the zeolite, and optimizing the acid strength of the active site,
It is possible to sufficiently achieve the isomerization reaction of xylenes, while suppressing the intermolecular rearrangement reaction of methyl groups, and selectively promoting the deethyl reaction by optimizing the amount of platinum. Certain things have been made clear by the present invention. The catalyst composition of the present invention KFi contains synthetic or natural refractory inorganic oxides commonly used as binders for zeolite catalysts, such as silica, alumina, silica-alumina, kaolin, silica-magnesia, etc. good. The content of zeolite as a catalytically active component in the catalyst composition is generally 1 to 99% based on the weight of the catalyst composition.
% by weight, preferably from 10 to 90% by weight. The catalyst composition may also contain other components within a range of pressures that do not substantially affect its reaction characteristics. As described above, the catalyst composition of the present invention is a crystal represented by the formula (1) whose cation side is ion-exchanged with at least one cation selected from the group of beryllium, strontium, and barium at a high exchange rate. It contains aluminosilicate zeolite and platinum in an amount that has a relationship between the cation and the above formula 4 R-1 to 2000, and has an excellent ability to isomerize xylenes,
It also has an ethylbenzene deethylation rudder, and has excellent properties in that intermolecular rearrangement reactions of methyl groups in xylenes are suppressed. For ease of understanding, the catalyst composition of the present invention can be roughly divided into the following (1) to 01υ. It can be obtained by the following method. Of course, the catalyst composition of the present invention can be produced by methods other than these, or by partial modification of these methods. and a method in which the material is calcined to contain at least one cation of beryllium, strontium, and barium, and then platinum is supported by a conventional method, and further molded by a conventional method using the above-mentioned binder. (1+D A method in which K-based zeolite is made to contain at least one cation of beryllium, strontium, and barium through ion exchange and calcination, and then molded with a binder to further support platinum. A method in which the material is molded together with a binder, and then ion exchanged and calcined to contain at least one cation of beryllium, strontium, and barium, and then supported with platinum. The cation contained in the above-mentioned cation site may be an alkali metal derived from a synthetic raw material, or after synthesis, a mineral acid as a proton source or an ammonium compound such as ammonium chloride as an ammonium ion source may be used. Beryllium, which may be hydrogen ions or ammonium ions introduced by ion exchange, is added to the cation site of such raw material zeolite.
The introduction of at least one cation of strontium and barium is carried out according to a known method. That is, this can be carried out by contacting the zeolite with an aqueous solution of chloride, nitrate, etc. containing ions of the metal to be exchanged. The amount of salt used at this time can be arbitrarily selected, but it is preferably in the range of 1 to 100 equivalents, particularly 10 to 50 equivalents, based on the alumina in the zeolite. ~20% by weight,
In particular, it is preferably in the range of 5 to 10% by weight, and in the case of a patch type, the contact operation is repeated several times depending on the desired amount of metal ions introduced into the cation site, but there is no problem in using a flow type. Ion exchange proceeds at room temperature, but heating treatment is also possible to increase the exchange rate.
Such a temperature is usually preferably in the range of 50°C to 95°C. Furthermore, when two or three of beryllium, strontium, and barium are to be introduced, the order of their exchange may be arbitrary, or a mixed solution may be used. Various beryllium, strontium or barium compounds can be used for ion exchange, including nitrates, carbonates, chlorides, perchlorates and other inorganic compounds. Salt is preferably used. In addition, although any organic salt can be used for acetate, nitrates and chlorides are particularly preferred.
Before carrying out ion exchange, 1 liter of raw material zeolite is added in advance.
Heat treatment can also be carried out at a temperature of 00 to 700°C, preferably 200 to 600°C, in an oxygen atmosphere such as air, or in an inert gas atmosphere such as nitrogen, for 1 to 50 hours, which is generally preferred. A catalyst can be obtained. The zeolite ion-exchanged with at least one of beryllium, strontium, and barium has 10
After heat treatment at a temperature of 0 to 700C, preferably 200 to 600C in an oxygen atmosphere such as air or an inert gas atmosphere such as nitrogen for about 1 to 16 hours, it is modified with platinum. Of course, as described in (1) above, ion-exchanged zeolite may be in powder form, teared, or molded with a binder.The modification of zeolite with platinum is different from that of ordinary zeolite. This can be carried out by a method known as a method of ion-exchanging the metal or a method of supporting the metal. For example, a zeolite containing at least one cation of beryllium, strontium, and barium may be contacted with a water-soluble or water-insoluble medium containing a dissolved platinum compound. Such platinum compounds include halides, oxides, sulfides, oxyacid salts, @compounds, and the like. For example, water-soluble platinum compounds [e.g.
Platinum may be supported on zeolite by impregnating an aqueous solution of t p t cL6・6HyO, Pt062] in zeolite, and then removing water by evaporation. The υ platinum may be ion-exchanged by immersing the zeolite in an aqueous solution of a platinum compound having ion-exchange ability such as R10, filtering the solution, and thoroughly washing the zeolite. Zeolite modified with platinum in this way has a
Heat treatment can be, and is preferred, at a temperature of 700°C, preferably 200-600°C, in an oxygen-containing atmosphere such as air, or under an inert gas atmosphere such as nitrogen, for about 1 to about 16 hours. When the zeolite thus obtained is ion-exchanged with at least one of beryllium, strontium, and barium and modified with platinum, it can be molded into various shapes, such as pellets or tablets, depending on the desired state. After that, it can be subjected to the reaction of the present invention. When molding the zeolite, the above-mentioned refractory inorganic oxide is used. When used, the catalyst composition prepared in this way can be heated to 200 to 600
The treatment is carried out at a temperature of 0 DEG C., preferably 250-550 DEG C., but it is usually preferable to perform this reduction treatment after charging the reactor. Next, regarding the method for isomerizing xylenes according to the present invention, which comprises contacting the above-mentioned catalyst composition with a raw material mixture containing at least one xylene isomer having a thermodynamic equilibrium concentration or lower in a gas phase. explain. The catalyst composition of the present invention described above is extremely excellent as an isomerization catalyst for xylenes. The aromatic hydrocarbon raw material used in this case is a raw material mixture having at least one xylene isomer having a thermodynamic equilibrium concentration or less. As is well known, xylene has three types of isomers: ortho-, meta-, and noolar isomers, and when a mixture of these three isomers in any ratio is used in an isomerization reaction, the isomerization reaction It is known that an equilibrium state is reached when the ratio of these three isomers reaches a certain value, and isomerization apparently does not proceed any further. In this equilibrium state, xylene The composition of the isomer mixture is called E thermodynamic equilibrium composition, and this thermodynamic equilibrium composition differs slightly depending on the temperature, for example, the equilibrium of the xylene isomer mixture at the temperature shown below or as follows. [1] In the case of a mixture of only three xylene isomers [
427°C]; p-xylene 23.4% by weight m-xylene 52.1% by weight O-xylene 24.5% by weight [■] In the case of a xylene isomer mixture containing ethylbenzene [427°C]; ethylbenzene 8.3% by weight % p-xylene 21.5% by weight m-xylene 47.8% by weight 0-xylene 22.4% by weight "Mixture containing" refers to a mixture of xylene isomers in which the concentration of at least one of the three isomers of xylene deviates from the concentration in the thermodynamic equilibrium composition. The aromatic hydrocarbon feedstock used as starting material in the process of the invention can consist solely of a mixture of xylene isomers. Alternatively, it may be a mixture of a xylene isomer mixture and other aromatic hydrocarbons such as ethylbenzene, benzene, toluene, ethyltoluene, trimethylbenzene, diethylbenzene, ethylxylene, tetramethylbenzene, and the like. In the latter case, it is desirable that the xylene isomer mixture generally account for 30 parts by weight or more, preferably 50 parts by weight or more, based on the weight of the aromatic hydrocarbon feedstock. In the method of the invention, the raw material mixture which can be used particularly advantageously is a C8 aromatic hydrocarbon fraction obtained from petroleum reforming, pyrolysis or hydrocranking, -
This fraction, in addition to the xylene isomer mixture, also contains ethylbenzene of the same number of carbon atoms. In the present invention, inter alia, these xylene isomer mixtures and ethylbenzene are added together, based on the weight of the fraction. So at least 8
Very advantageous results are obtained when using a C8 aromatic hydrocarbon fraction which accounts for 0% by weight, preferably more than 90% by weight. The isomerization of the aromatic hydrocarbon raw material described above can be carried out under xylene isomerization reaction conditions known per se, except for the use of the above-mentioned specific catalyst. However,
The reaction temperature is generally 280-500°C, preferably 300°C.
~450°C, and the reaction pressure is generally from normal pressure to 301 cd, preferably from normal pressure to 25 cd.
In implementing the uninvented isomerization method, which can be freely selected within the range of ~/d, the feed ratio of the raw material mixture can be varied widely depending on the type of hydrocarbon raw material and/or catalyst used, etc. However, it is advantageous to feed at a weight unit hourly space velocity, generally from about 0.1 to about 200, preferably from 0.1 to SO. Further, the isomerization of the present invention is more preferably carried out in the presence of hydrogen. The hydrogen supply ratio at that time can be varied widely depending on the type of raw material mixture and/or catalyst composition used, but it is generally 1 to 30, preferably 1, expressed as a molar ratio of hydrogen/raw material mixture. It is appropriate to supply at a ratio within the range of ~2o. In addition, when carrying out the isomerization reaction of the present invention, prior to the reaction or when the activity falls below a certain level after carrying out the isomerization reaction, by carrying out the commonly known chlorination treatment of zeolite, Increasing the initial activity of the catalyst,
Alternatively, the activity after regeneration, especially the isomerization activity of ethylbenzene, can be returned to the bulk level. In addition, such chlorination treatment can be carried out on the catalyst composition of the present invention at the time of catalyst preparation, by introducing chlorine into the catalyst, and in some cases, raw materials can be treated during the isomerization reaction. This can also be done by incorporating a chlorine compound as a component of the mixture. According to the method for isomerizing xylenes using the catalyst composition of the present invention described above, it is possible to achieve the excellent advantages of sk as described below compared to conventional similar techniques, and contribute to industry. It is extremely large in places. In other words, according to the method of the present invention, the intermolecular rearrangement reaction of the methyl group of xylenes, the disproportionation reaction of tsumaxylene, and the transalkyl reaction between xylene and ethylbenzene are suppressed, so that xylene loss is significantly reduced and xylene loss is suppressed. According to the method of the present invention, the deethylation reaction of ethylbenzene is promoted, and as a result, the transalkylation reaction of ethylbenzene and xylene is suppressed, thereby increasing the isomerization yield of xylene. The conversion yield is improved. Further, according to the method of the present invention, undesirable side reactions such as demethylation reaction of xylenes and hydrogenation reaction of benzene rings are suppressed, and the isomerization yield of xylene is improved. Hereinafter, the present invention will be further explained with reference to Examples, but the present invention is not limited to these Examples in any way. Example 1 (Preparation of al H-ZSM-5) Zeolite ZSM-5 was synthesized according to the method disclosed in US Pat. No. 3,965,207. During the synthesis, tri-n-propylamine and n-provil bromide were added as organic nitrogen cation sources. 1lt of synthetic material
It was identified as ZSM-5 from the X-ray diffraction pattern. The obtained ZSM-5 was filtered, thoroughly washed with water, and then dried at 100°C for 8 hours in an electric dryer, then at 200°C for 16 hours, and further dried at 450°C for 16 hours in an electric muffle oven under air circulation.
Baked for an hour. Thereafter, 250f was subjected to ion exchange with 1.5 t of a 5% by weight ammonium chloride aqueous solution at 80°C for 24 hours. This operation was repeated two more times. After that, it was thoroughly washed with water and dried in an electric dryer at 100°C for 8 hours, then at 200°C.
H+-type ZS
M-5 was obtained. The sodium content of this thing is 0.05
% by weight, and the silica/alumina molar ratio was 71. (Hereinafter, this will be referred to as zeolite A-1) (()) Be-28M5 (7) Under controlled air flow 450. Zeolite A-11Of, which had been calcined at C for 8 hours, was ion-exchanged for 6 hours under reflux in an aqueous solution in which 7.5f of beryllium nitrate trihydrate was dissolved in 100 - of water. This operation was repeated once more. After that, wash thoroughly with water,
BlB by drying with 20 (In) in an electric dryer for 8 hours and calcining for 8 hours at 450 °C in a heated electric muffle oven.
lll-ZS was obtained. The beryllium content of this stuff is 0.
．． 15 weight percent and Be/ALt −0,
79 (hereinafter referred to as zeolite B-1). (c) Preparation of sr-ZSM 5 Br-28M5 was obtained in the same manner as in (b) above, except that an aqueous solution in which strontium nitrate 21.2 f was hydraulically dissolved in 200117 was used. The strontium content of this product was 1.06% by weight, which was sr/Am/o, 57 (hereinafter referred to as zeolite C-1). @) Preparation of Ba-ZSMS Ba-28M5 was obtained by the same method as in (b) above except that 200 ml of barium chloride A 23.6 f was dissolved in water (D). <
IJum content a is 1.14% by weight and Ba
/A14=0.39. (Hereinafter, this will be referred to as zeolite D-1) (e) pt/H-zsMs, Pt/BlB111
-ZS, pt/5r-zsns and Pt/Ba-28
Preparation of M5 Aqueous chloroplatinic acid solution containing 7.53 μl/l of platinum.
20 - of 67WIK water was added, and 5f zeolite A-1 was suspended in this aqueous solution. Then, after holding at 70°C for 6 hours, the solvent was distilled off at 40°C using a rotary evaporator, dried at 200°C for 8 hours in an electric dryer, and further heated at 450°C in an electric muffle oven under air circulation. By firing for 8 hours, Pt
/ H-28M5 was obtained (hereinafter referred to as zeolite A-
2). The platinum content of this product was 0.1% by weight. Zeolite) B-1. pt/Be using zeolite (!-1) and zeolite D-1 under exactly the same conditions as zeolite A-2.
-28M5, Pt/Sr -ZSM S and P
t/Ba-ZSM S (hereinafter referred to as zeolite B-2, zeolite C-2 and zeolite D-2)
). The R values of Zeolite B-2° Zeolite C-2 and Zeolite D-2 are a2. s, 2
5.1 and 17.1. Example 2 Regarding the catalyst composition obtained in Example 1, the 1,3.5-)Q methylbenzene adsorption rate (RA), which represents the characteristics of the catalyst composition of the present invention, was measured. That is, zeolites B-2, C-2, and D-2, which are catalyst compositions of the present invention, zeolite A-2, which is a comparative example, and zeolite Tom-1, which is a standard.
(H-ZSMS>) was calcined in an electric Matsufuru furnace at 450°C for 8 hours, and then about 1 liter was accurately weighed into a weighing bottle.Then, the zeolite was placed in a desiccator containing 1.3.5-)limethylbenzene. at 25℃, 30±5ms 11
1.3.5 by standing for 10 minutes under reduced pressure of
-) Limethylbenzene was adsorbed. After that, the 1.3.5-)limethylbenzene in the desiccator was removed, and after being kept in the desiccator under the same conditions and for the same time as above, it was weighed and the adsorption amount V per unit weight of zeolite was determined.
was measured. The adsorption rate (RA) is the adsorption amount Vo of standard zeolite) A-1.
It can be determined by the ratio of the adsorption amount v8 of the catalyst composition to K, that is, the following formula: %, and the results are summarized in Table 1. From the results in Table 1, the catalyst composition of the present invention B-2,0
The RA of -2 and D-2 is smaller than that of Comparative Example A-2, and it can be seen that the larger the cation, the smaller the RA. Example 3 Regarding the catalyst composition obtained in Example 1, the (ethylbenzene/xylene) reaction selectivity (RB), which characterizes the catalyst composition of the present invention, was measured. That is, zeolite B-2, l:! of Example 1, which is the catalyst composition of the present invention. -2, D-2 and zeolite (comparative example) A-2 at 50% by weight each.
The pellet was molded into a pellet of 10 to 20 meshes containing r-alumina. The pellet was calcined in an electric furnace at 450°C for 8 hours, and 3f was charged into a flow-through normal pressure fixed bed reaction tube, and the catalyst bed temperature was adjusted to 400°C. Platinum contained in the catalyst was reduced by flowing hydrogen at a rate of 1 OOm/i for 2 hours. Furthermore, under normal pressure, ethylbenzene/xylene-
IS/85 (weight ratio) aromatic hydrocarbon composition 12f (
WH8V −4Hr−′) and hydrogen/the hydrocarbon=1
/l (molar ratio) of hydrogen was supplied. The temperature of the catalyst bed was adjusted to such an extent that the conversion rate of ethylbenzene was 30 degrees.
14. After analyzing the product composition at 5 o'clock after the beginning of the slow feed, the ethylbenzene conversion rate (
KBDISA), xylene conversion rate (xYLOEI8
), and RB = ”'msA/xYI, :ls
The (ethylbenzene/xylene) reaction selectivity (RB ) defined as s was measured. The results are summarized in Table 2K. From the results in Table 2, the catalyst compositions B-2 and C of the present invention
RB of -2 and D-2 is significantly higher than that of A-2 [
It can be seen that this tendency becomes more pronounced as the cation becomes larger. Table-2 Example 4 Catalyst composition zeolite B-2, D- obtained in Example 1
Regarding No. 2, an isomerization reaction of mixed xylene raw materials was carried out. As in Example 3, 1/1 weight ratio of alumina gel for chromatography (r-alumina = 300 mesh) was added to each of zeolite) B-2 and D-2, and mixed thoroughly.
It was molded to a size of 0 mesh. The obtained molded product was fired for 8 hours at 450° C. in an air atmosphere in an electric muffle furnace, and then filled into a flow-type pressurized fixed bed reactor. Thereafter, reduction treatment was performed at 400° C. for 2 hours in a hydrogen stream, and subsequently, a xylene isomerization reaction was performed using mixed xylene having the composition shown in Table 3 as a raw material. reaction conditions,
The product composition is shown in Table 3. The various headquarters) and abbreviations used in the table have the following meanings. (Deethylation) - Total number of moles of IcB (disappeared) Aromatic nucleus loss rate Value) = [PX]F, : Concentration of paraxylene in the xylene 3 isomer in the feed liquid (wt%) ' [PX]p : Product xylene 3 in liquid
Concentration of para-xylene in isomers (wt%) [PX″JP2: Equilibrium concentration of para-xylene in xylene isomers at reaction temperature! (wt%) [EB], ; FiB concentration in feed liquid (wt%) [
yB]P; ]IcB concentration (weight) in product liquid [
X] F: Concentration of xylene 3 isomer in feed liquid (wt%) [X) A; Xylene isomerization catalyst in product liquid (weight S) From the results in Table 3, B-2, C-2 and D- It can be seen that No. 2 is an excellent xylene isomerization catalyst having high isomerization activity, extremely low xylene loss rate, and deethyl removal activity. Table-3 Group Leading car @) ;(010,0,090,03 move
Continued amendment book June 1981? To the Commissioner of the Japan Patent Office, Patent application filed on June 3, 1982 (2) 2 Name of the invention PM medium composition and method for isomerizing xylenes 3 Relationship to the case of the person making the amendment Patent applicant Chiyoda-ku, Tokyo 2-1-1 Uchisaiwai-cho Teijin Yuka Co., Ltd. Representative Norio Tokusue 4th generation Director 2-1-1 Uchisaiwai-cho, Chiyoda-ku, Tokyo (Iino Building) Contact information (506) 4481 J-',,
-5@Correct, "Claims" and Detailed Description of 1 Invention" column 6 of the subject specification 6 @Correct contents (1) Correct the scope of claims in the specification as shown in the attached sheet (21 Clarification) 6] “Collateral” on page 6, line 7 of the Ministry of Justice is “carrier”]
Correct. (3) Change “×-μm” on page 13, line 3, to l X ---J
]0θW W . t4i MT "preparation" on page 29, line 8 as "6 Yubushi"
Correct (51 Same page 41, line 3, 1 "Isomerization activity" is changed to "Deethyl activity") 4. Above 1 (1) General formula CI+
-= -(Crystalline aluminosilicate heptaolide represented by II, and the following formula ■ R=-,
Contains platinum as the main active ingredient in an amount corresponding to R expressed as 1 to 2000, (2) I
, 31 D) Limethylbenzene adsorption rate (RA) f) is in the range of 1 to 0.9, +31 (ethylbenzene/-!-silene) reaction a
Catalyst composition characterized in that the selectivity (RB) is at least 60. 2 y in the crystalline aluminosilicate heptaolide
The catalyst composition according to item 1, wherein the catalyst composition is 30 to 100. 3 X in the crystalline aluminosilicate heptaolide
The Asahi GM composition according to item 1, wherein is 0.3 to 0.8. 4. The catalyst composition according to item 1, which contains platinum in which R represented by @kinitan corresponds to 10 to 1000. 5 The group consisting of the ga-based aluminosilicate zeolite or zeolite) ZSM-s, ZSM-11° zeolite) 28M-12, 5a) ZSM-35 and zeolite ZSM-38 2. The catalyst composition according to claim 1, which is modified from at least one kind of zeolite selected from the following. 6(1) General formula CI+ xMO-(+ -x)N, 041,0. -yS io
, -・"-(Contains crystalline aluminosilicate heptaolide represented by Il and platinum represented by the following formula with R corresponding to 1 to 2000 as main active ingredients, +21 1.3.5 − )
Limethylbenzene adsorption rate (RA) is in the range of 0.1 to 0.9, +31 (ethylbenzene/xylene) Bt reaction M
A raw material mixture of xylenes having a lipid content (RB) of at least 60 and containing at least one quinolene isomer having a thermodynamic equilibrium concentration or less in the gas phase is brought into slight contact with the catalyst composition. Isomerization method. 7. The method for isomerizing xylenes according to item 6, wherein the raw material mixture contains ethylbenmino. 8. The method for isomerizing xylenes according to item 6, wherein the contact is carried out in the presence of hydrogen.

Claims (1)

[Claims] 1. (1) General formula (1) % formula % (at least one cation selected from 11, x
tit O, 1-1, ya15-20 otel: Yes. A crystalline aluminosilicate zeolite represented by \/ and the following formula 〇) 1' However, in formula (n), It + It , ms
and 〜4 is the weight of platinum based on the weight of ゝ【 ：；・、y
is the same as equation (1). ! \

Contains platinum as the main active ingredient in an amount corresponding to R expressed as / from 1 to 2000, and (2) has an l,a,s-trimethylbenzene adsorption rate (RA) of 0.1 to 0.9. (3) (ethylbenzene/xylene) reaction selectivity (RB) of at least 60. 2. y in the crystalline aluminosilicate zeolite
3. The catalyst composition according to claim 1, wherein 3. X in the crystalline aluminosilicate zeolite
2. The catalyst composition according to claim 1, wherein is from 0.3 to 0.8. 4. R represented by the above formula 〇) is 1o to ioo. 2. The catalyst composition according to claim 1, containing platinum corresponding to . 5. The crystalline aluminosilicate zeolite is modified from at least one zeolite selected from the group consisting of zeolite ZSM-5, zeolite Z8M-1, zeolite ZSM-12, zeolite ZSM-35, and zeolite ZEIM-38. 2. The soap composition according to claim 1, which is 6, tl) Crystalline aluminosilicate zeolite represented by general formula (1) % formula % (1) Contains (2) 1,3.5-
) Limethylbenzene adsorption rate (RA) is 0.1 to 0.9
(3) (Ethylbenzene/xylene) reaction selectivity (
RB) is at least 6o, a method for isomerizing xylenes, comprising contacting a catalyst composition in a gas phase with a raw material mixture containing xylene isomer gold in which at least one isomer has a concentration below the thermodynamic equilibrium concentration. . 7. The method for isomerizing xylenes according to item 6, wherein the raw material mixture contains ethylbenzene. 8. The method for isomerizing xylenes according to item 6, wherein the contact is carried out in the presence of hydrogen;