KR100303457B1 - A catalyst comprising a supported noble metal for alkyl aromatic hydrocarbon isomerization - Google Patents

Abstract

(1) 0.1 to 0.4% by weight of Pt, or (2) 0.1 to 0.4% by weight of Pt or 0.2 to 0.8% by weight of (1) a catalyst comprising a noble metal (s) Pd and 0.01 to 0.20% by weight of Re and 0.05 to 0.50% by weight of Sn and 0 to 15% by weight of ZSM-5 zeolite and 40 to 80% by weight of zeolite having 10 to 60% Alumina.

Description

[Title of the Invention]

A catalyst comprising a supported noble metal for alkyl aromatic hydrocarbon isomerization

DETAILED DESCRIPTION OF THE INVENTION [

[0001]

The present invention relates to a catalyst comprising a supported Group VIII noble metal (s) suitable for the isomerization of alkylaromatic hydrocarbons and to a process for preparing the same. More specifically, the present invention relates to a catalyst comprising a support containing zeolite and alumina and an active ingredient containing Pt, and a process for preparing the same.

BACKGROUND OF THE INVENTION [

C ₈ aromatic hydrocarbon is typically the para-xylene (PX), meta-xylene (MX), olto - it says a mixture of xylene (OX) and ethylbenzene (EB), may be obtained from catalytic reforming or cracking petroleum reum. PX and OX can be used in many fields, for example as starting materials for polyester and anhydrous benzoic anhydride synthesis. PX and OX can be separated from a mixture of C ₈ aromatic hydrocarbons and the raffinate can be converted to a near-equilibrium mixture of PX, MX, and OX by isomerization. This is an efficient way to increase the PX yield.

A number of isomerization methods such as OCTAFINING method (Engelhard Company), ISOMAR method (UOP company), ISOLENE-II (Toray Corporation) and the like are used to increase the conversion of isomerization of C ₈ aromatic hydrocarbons and conversion of ethylbenzene to xylene Have been developed, wherein a dual function catalyst comprising the supported noble metals is used, which is described in U.S. Patent No. 3,67,881; 3,767,721; German Patent No. 2,823,567. Commercial catalysts (EMC and UOP) most commonly used for isomerization in recent years are bifunctional catalysts containing supported noble metal (s). The compositions of these catalysts are H-mordenite-alumina with Pt and / or Pd, which can be prepared by removing the sodium cations by ion exchange of the Na-mordenite powder with an ammonium salt solution or dilute hydrochloric acid, After the calcination is performed to form H-mordenite in which sodium cations have been removed to some extent, the resultant is mixed with alumina and a binder having noble metal Pt or Pd, and finally molded to produce a catalyst. In this process, the yield is relatively low and the energy consumption rate is relatively high.

EP 458,378 discloses a catalyst for the isomerization of C ₈ aromatic hydrocarbons, which comprises Pt as the active component and comprises 2 to 3% by weight of alkali metal cations as support and a binder selected from trihydrate-alumina or gamma-alumina ≪ / RTI > containing H-mordenite. The catalyst may be prepared by mixing H-mordenite with H-mordenite and then mixing with a binder, or alternatively mixing mordenite with a binder and molding and ion-exchanging to form H-zeolite, finally impregnating with Pt, Lt; / RTI >

H-Maodenite Chinese Patent CN 89100145X also discloses a catalyst comprising supported noble metals for C _B alkylaromatic hydrocarbon isomerization, which comprises H-Na-mordenite and alumina as supports.

Since the invention of ZSM series of zeolites has been developed, a number of isomerization catalysts containing such zeolites have been developed, including those containing ZSM-5 zeolites (USP 4,100,262), those containing ZSM-25 zeolites EP 15702), those containing zeolite ZSM-39 (US Pat. No. 4,357,233), those containing zeolite with a crystalline intermediate of ZSM 5 / ZSM 11 (EP 18,090; EP 65,401), the molar ratio of silica to alumina 12 or more and containing a zeolite having a constraint index of 1 to 12 (USP 4,428,819).

USP 4,694,114 discloses a catalyst for the isomerization of alkylaromatic hydrocarbons, which includes ZSM-23 and alumina as supports and includes hydrogenation-dehydrogenation metal (s) such as Pt, Pd or Ni.

EP 390,058 discloses a catalyst for the isomerization of C ₈ aromatic hydrocarbons, which comprises ZSM zeolite and alumina with a molar ratio of silica to alumina of 30-200 as support and contains Pt-Sn and / or In.

USP 4,467,129 discloses a catalyst containing a double zeolite system for the isomerization of C ₈ alkylaromatic hydrocarbons, which comprises as support an acidic mordenite and a specific acidic zeolite (e.g. ZSM-5, -8, -11) , Inert alumina, and includes metal components selected from Re, Mo, W, The catalyst can be prepared by homogeneously mixing a double zeolite system with a diluent (e.g., alumina), then adding a binder (e.g., alumina gel), molding by kneading and extrusion After drying and firing, it is exchanged with an ammonium salt solution so that the sodium content is adjusted to a predetermined amount, followed by baking and finally, impregnation with a metal component to activate.

On the basis of the prior art, it is an object of the present invention to provide two catalysts with excellent properties in the isomerization of alkylaromatic hydrocarbons, by means of the isomerization process with these catalysts, the para-, meta- and ortho-alkylaromatic hydrocarbons An equilibrium mixture can be obtained.

Another object of the present invention is to provide a method for producing the aforementioned catalyst.

Other objects of the present invention can be clarified from the present specification including the following examples.

[Summary of the Invention]

The catalyst provided in the present invention is characterized in that (1) 0.1 to 0.4 wt% of Pt, (2) 0.1 to 0.4 wt% of Pt or 0.2 to 0.8 wt% of Pd and 0.01 to 0.20 wt% of Re and 0.05 to 0.50 weight of Sn and 10 to 60 weight% of a zeolite having a MOR structure as a support, 0 to 15 weight% of ZSM-5 zeolite and 40 to 80 weight% of alumina. The catalyst may be prepared by mixing Na-zeolite with alumina or a precursor thereof, followed by extrusion and calcination to produce a support; The support is ion-exchanged with an ammonium salt solution so that the exchanged sodium cation content is 30 to 95%, followed by drying, impregnation with a solution of the active ingredient metal compounds, and finally activation.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment of the present invention, the catalyst comprises 0.1 to 0.4% by weight (based on the weight of the catalyst) of Pt as the active ingredient. In another embodiment of the present invention, the catalyst comprises three kinds of metal elements, Pt, Re and Sn; Or Pd, Re and Sn, the contents thereof (based on the weight of the catalyst) are as follows; 0.1 to 0.4% by weight of Pt, 0.01 to 0.20% by weight of Re and 0.05 to 0.50% by weight of Sn; Or 0.2 to 0.8% by weight of Pd, 0.01 to 0.20% by weight of Re and 0.05 to 0.50% by weight of Sn. The support for these two catalysts is a composite support comprising zeolite and alumina wherein the zeolite is a zeolite having a MOR structure or a zeolite having a MOR structure and a zeolite zeolite system consisting of ZSM-5 zeolite . The contents of the zeolite, ZSM-5 zeolite and alumina having the MOR structure are 10 to 60%, 0 to 15% and 40 to 80%, respectively, of the weight of the support.

The above zeolite having a MOR structure has an anhydrous formula (in terms of molar ratio of oxide) of 1.0 to 7.0 Na ₂ O.Al ₂ O ₃ .10 to 60 SiO ₂ and has an X-ray diffraction Pattern, and the adsorbed weight ratio of n-hexane to cyclohexane is less than 1.0. Preferably, the zeolite having the MOR structure used in the catalyst of the present invention has a molar ratio of silica to alumina of 10 to 30 and a crystal size of less than 1 mu m. Zeolites having a MOR structure are prepared using amorphous aluminosilicate microspheres, sodium hydroxide and water as starting materials and using sodium chloride or sodium chloride triethanolamine as a templating agent. A detailed description of the zeolite and its preparation method is disclosed in Chinese Patent Application No. 95116456.2.

Preferably, the ZSM-5 zeolite used in the present catalyst has a molar ratio of silica to alumina of 100 to 500 and a crystal size of less than 1 mu m.

[Table 1]

Here, the abbreviations for strength are specified as follows:

Very strong (VS) = 80-100%

Strength (S) = 60-80%

Medium (M) = 40-60%

Weak (W) = 20-40%

Very weak (VW) < 20%

The alumina used in the composite support may be gamma-alumina obtained from the hydrolysis of etha-alumina or gamma-alumina, preferably alkoxylaluminum, especially gamma-alumina obtained from the hydrolysis of alkoxylaluminum in which the alkyl group is a lower alkyl group, Al ₂ O ₃ , which is prepared as disclosed in CN 85100218.8.

The process for preparing the catalyst comprises the following four steps:

1. Preparation of support: A mixture of Na-zeolite and alumina or a precursor thereof is extruded and then calcined to prepare a support. Specifically, a mixture of Na-zeolite having a MOR structure or Na zeolite having a MOR structure or Na-zeolite having a MOR structure and ZSM-5 zeolite at a predetermined ratio with alumina or a precursor thereof, Dilute nitric acid is added to facilitate extrusion. The concentration of dilute nitric acid is generally 1 to 5% by weight, preferably 1.5 to 3.0% by weight. The weight ratio of diluted nitric acid added to the tactical ring mixture is from 1: 0.25 to 0.60, preferably from 1: 0.35 to 0.45. Thereafter, it is mixed and kneaded, extruded, dried and calcined in air at 470 to 650 ° C, preferably at 500 to 600 ° C for 2 to 8 hours, preferably for 3 to 6 hours.

2. Ammonium cation exchange step of the support: The support is ion-exchanged with an ammonium salt solution so that the exchanged sodium cation content in the zeolite reaches 30-95%. Specifically, the reaction is carried out at a temperature between room temperature and 120 ° C, preferably at 85 to 100 ° C, for 1 to 6 hours, preferably 1 hour, until the exchanged sodium cation content reaches 30 to 95%, preferably 55 to 85% The support is subjected to ion exchange several times with 0.1 to 0.8N, preferably 0.2 to 0.5N solution of an ammonium salt selected from ammonium chloride, ammonium nitrate and ammonium sulfate, followed by filtration Wash the free Na ⁺ .

3. Impregnation of the active component: The dried support is impregnated with a solution of the active metal compound. (1) a solution of a platinum compound; or (2) a solution of Pt, Re and Sn; Or a solution of compounds of Pd, Re and Sn for 8 to 60 hours, preferably 12 to 36 hours, followed by filtration and drying. The metal compounds are soluble compounds commonly used in the impregnation process, for example chloroplatinic acid, palladium chloride, perrhenic acid or soluble tin salts (for example SnCl ₂ ). Pt of the first embodiment catalyst and Sn of the second embodiment catalyst may be pre-impregnated in alumina and then mixed with the zeolite.

4. Activation step of the catalyst: The activation step is carried out in air at 400 to 600 ° C, preferably at 450 to 550 ° C for 1 to 10 hours, preferably for 3 to 6 hours.

Compared with the catalysts of the prior art, the two types of catalysts provided in the present invention utilize a specific zeolite having a MOR structure and a composite support of a specific composition and bind active metal components to enhance the activity, selectivity and stability of the isomerization reaction To achieve a near equilibrium mixture of para-, meta- and ortho-alkylaromatic hydrocarbons within the isomerization process. These two series of catalysts can be suitably used not only for the isomerization of C ₈ aromatic hydrocarbons containing 10 to 40% by weight of ethylbenzene but also for the isomerization of C ₉ and C ₁₀ aromatic hydrocarbons, so that 1,3,5-trimethylbenzene or Para-diethylbenzene &lt; / RTI &gt;

The process for preparing a catalyst provided in the present invention not only fully exerts the function of the active ingredient but also optimizes the synergistic effect between the active ingredient and the support. This manufacturing method also reduces the pollution from the support material and the loss of zeolite during the ion exchange process and increases the yield of zeolite and exchange efficiency with ammonium salt.

[Example]

The following examples are provided to further illustrate the present invention without limiting it.

In this embodiment, zeolites with MOR structures are prepared according to the method disclosed in CN 95116456.2, and ZSM-5 zeolite and gamma-alumina are commercial products.

The symbols used in this embodiment have the following meanings:

<C ₇ ^{N + P} - Cycloalkane and alkane having less than 7 carbon atoms;

C ₈ ^{N + P} - Cycloalkane and alkane having 8 carbon atoms;

B - benzene;

t-toluene;

EB - ethylbenzene;

PX-para-xylene

MX-meta-xylene

OX-ortho-xylene

In an embodiment, the conversion of PX / ΣX, C ₈ and EB yield of hydrocarbons is calculated as follows:

PX / ΣX

= Concentration of PX in the product / concentration of (PX + MX + OX) in the product] 100%

The yield of C ₈ hydrocarbons

= [Concentration of ΣC ₈ in the concentration / feedstock ΣC ₈ in the product] × 100%

Where _{the concentration of} ΣC _{8 = the concentration of} (PX + MX + OX + EB + C ₈ ^{N + P} ).

Conversion ratio of EB = [(EB concentration in the feedstock - EB concentration in the product) / EB concentration in the feedstock] × 100%

[Comparative Example 1]

Comparative Catalyst Sample Preparation of Pt-Re / Moordenite-Gamma-Alumina:

25 g of mordenite with a molar ratio of silica to alumina of 12.5 (based on dry weight) was mixed with 75 g of gamma-alumina and then 40 ml of a 2 wt% nitric acid solution was added. The mixture was mixed and kneaded, molded by extrusion, dried at 110 to 120 DEG C for 1 hour, and calcined at 550 DEG C for 4 hours in air to prepare a support. The prepared 10 g of the support was ion-exchanged with 25 ml of 2 wt% ammonium chloride solution at 90 ± 10 ° C. for 2 hours, the free Na ⁺ was washed and dried. The calculated Na ⁺ content was 75%, calculated as Na ⁺ content in the zeolite before and after ion exchange.

The prepared ammonium cation-exchanged support was impregnated with a solution of chloroplatinic acid and perrhenic acid until it contained 0.4 wt% Pt and 0.1 wt% Re. The support was dried and activated at 500 &lt; 0 &gt; C in air for 4 hours.

The thus-prepared comparative catalyst was referred to as Sample A.

[Comparative Example 2]

Comparative Catalyst Sample Preparation of Pt-Sn / Moordenite-Gamma-Alumina:

A comparative catalyst sample was prepared in the same manner as described in Comparative Example 1, except that the support contained 0.4 wt% 5 wt% Pt and 0.2 wt% Sn.

The thus-prepared comparative catalyst was referred to as Sample B.

[Comparative Example 3]

Comparative Catalyst Sample Preparation of Pt / mordenite-gamma-alumina:

Comparative catalyst samples were prepared under the same conditions and conditions as described in Comparative Example 1 except that the support contained 0.4 wt% Pt.

The thus-prepared comparative catalyst was referred to as Sample A '.

[Example]

Preparation of catalyst of the present invention

Except that starting from ZSM-5 zeolite having a molar ratio of silica to alumina of 150 and a zeolite having a MOR structure with a molar ratio of silica to alumina of 12.3, D, E, F, G, H, I and J having different compositions of catalyst samples B ', C', D ', E' and F 'with different compositions and the second embodiment. The compositions of all these catalysts and the catalysts of Comparative Examples 1, 2 and 3 are shown in Tables 2 and 3.

[Table 2]

The molar ratio of silica to alumina is 20;

** Molar ratio of silica to alumina 300.

[Table 3]

The molar ratio of silica to alumina is 20;

** molar ratio of silica to alumina 300;

*** Sn component was previously impregnated with gamma-Al ₂ O ₃ .

[Example]

This example illustrates that the catalyst provided in the present invention has excellent properties in xylenes isomerization.

In a 10 ml micro-reactor, the activity of the comparative catalyst in the isomerization of C ₈ aromatic hydrocarbons and the catalyst provided in the present invention was evaluated. The reaction conditions were as follows: 380 ℃, O.8㎫, hydrogen-to-hydrocarbon volume ratio of 1000/1, and H ₂ was passed once. The charged amount of catalyst was 5 g. The composition of the feedstock was (weight%):

<C ₇ ^{N + P} : 0.16; C ₈ ^{N + P} : 6.45; B: 0.53; T: 0.65; EB: 12.24; PX: 0.0; MX: 53.70; OX: 26.28

The results of the evaluation of the first embodiment catalyst at a weight hourly space velocity (WHSV) of 3.5 h &lt; ^-1 &gt; are shown in Table 4 (% by weight). The results of the evaluation of the catalyst of Example 2 at a weight hourly space velocity of 4.0 h &lt; ^-1 &gt; are shown in Table 5 (% by weight).

[Table 4]

[Table 5]

[Example 3]

This example illustrates that the catalyst provided in the present invention is suitable for isomerization under various process conditions.

Catalyst C 'of the first embodiment of the present invention and Catalyst E of the second embodiment of the present invention were tested under the same conditions of catalyst and the same feedstock in the same reactor as described in Example 2 under various process conditions. Hydrogen was also passed once.

The results of Catalyst C 'are shown in Table 6, and the results of Catalyst E are shown in Table 7.

[Table 6]

[Table 7]

[Example 4]

This example illustrates that the catalyst provided in the present invention is suitable for the isomerization of C ₈ aromatic hydrocarbons having different ethylbenzene contents.

The results of the isomerization of catalyst C 'at a weight hourly space velocity (WHSV) of 3.5 h ^-1 are shown in Table 8 and the results of isomerization of Catalyst E at a weight hourly space velocity of 4.0 h ^-1 are shown in Table 9 . Catalyst C 'of the first embodiment of the present invention and Catalyst E of the second embodiment of the present invention were used in the same reactor as described in Example 2 and under the same process conditions and the same catalyst amount, % And 11.25% by weight, respectively). The two types of C ₈ aromatic hydrocarbon feedstocks were each isomerized.

[Table 8]

[Table 9]

[Example 5]

This example illustrates that the catalyst provided in the present invention has good stability in isomerization.

The stability of the catalyst C 'of the first concrete example and the catalyst E of the second concrete example were measured under the conditions of a temperature of 380 to 383 캜, a hydrogen to hydrocarbon ratio (v / v) of 1,000: 1, a pressure of 0.8 to 0.9 MPa, Were tested in a 30 ml bench reactor.

The product composition of catalyst C 'after 1000 hours of operation at weight hourly space velocity (WHSV) of 3.5 h &lt; ^-1 &gt; was (weight%):

C ₈ ^{N + P} : 7.19; B: 0.33; T: 0.96; EB: 10.51; PX: 17.36; MX: 43.85; OX: 17.36, PX /? X: 22.09; yield of C ₈ hydrocarbon: 97.56; Conversion rate of EB: 15.38. After 1,000 hours of operation, the coke on the catalyst sample was only 1.47 wt%.

The product composition of Catalyst E after 1000 hours of operation at weight hourly space velocity (WHSV) 4.0 h &lt; ^-1 &gt; was (weight%):

C ₈ ^{N + P} : 8.15; B: 0.33; T: 0.96; EB: 9.80; PX: 18.36; MX: 42.05; OX: was 18.36, PX / ΣX: 23.23; C ₈ hydrocarbon Yield: 97.80; EB conversion rate: 19.93. The coke on the catalyst sample after only 1000 hours of operation was only 0.70 wt%.

[Example 5]

This example illustrates that the catalyst provided in the present invention are suitable to C ₉ aromatic carbon bovine isomerization lake.

Under conditions of 430 ° C, 0.8 MPa, liquid hourly space velocity (LHSV) of 3.1 h ^-1 and hydrogen to hydrocarbon ratio (v / v) of 1,000: 1, using catalysts C ' Trimethylbenzene was isomerized in a 10 mL microreactor. The reaction results are shown in Table 10.

[Table 10]

[Example 7]

This example illustrates that the catalyst provided in the present invention is equally suitable for the isomerization of C ₁₀ aromatic carbonate lake.

Under the conditions of 370 ° C, 0.7 MPa, liquid hourly velocity (LHSV) of 3.0 h ^-1 and hydrogen to hydrocarbon ratio (v / v) of 1,500: 1, using catalysts C ' The feedstock was isomerized in a 10 ml microreactor. The reaction results are shown in Table 11.

[Table 11]

* Indicates that the C ₁₀ aromatic hydrocarbons do not contain diethylbenzene.

Claims (36)

Zeolite with 0.1 to 0.4 wt.% (Based on the weight of the catalyst) of active ingredient and 10 to 60 wt.% (Based on the weight of the support) of the support as a support, 0 to 15 wt. ZSM-5 zeolite, and 40-80 wt% alumina (based on the weight of the support). The zeolite according to claim 1, wherein the zeolite having the MOR structure has an anhydrous formula (in terms of molar ratio of oxides) of 1.0 to 7.0 Na ₂ O · Al ₂ O ₃ · 10 to 60 SiO ₂ , Ray diffraction pattern and the adsorption weight ratio of n-hexane to cyclohexane is less than 1.0. [table] 3. The catalyst according to claim 2, wherein the zeolite having the MOR structure has a molar ratio of silica to alumina of 10 to 30 and a crystal size of less than 1 mu m. The catalyst according to claim 1, wherein the ZSM-5 zeolite has a molar ratio of silica to alumina of 100 to 500 and a crystal size of less than 1 m. The catalyst according to claim 1, wherein the alumina is etha-alumina or gamma-alumina. 6. The catalyst according to claim 5, wherein the alumina is gamma-alumina of high purity obtained from the hydrolysis of alkoxylaluminum. Mixing Na-zeolite with alumina or a precursor thereof, followed by extrusion and calcination to prepare a support; Impregnating the support with a solution of the active ingredient metal compound by ion-exchanging the support with an ammonium salt solution so that the exchanged sodium cation content of the zeolite is between 30 and 95%, and finally drying The method of claim 1, further comprising the step of activating the catalyst. 8. The method of claim 7, wherein the support comprises a mixture of a zeolite having a MOR structure, or a mixture of Na-zeolite and ZSM-5 zeolite having a MOR structure with alumina or a precursor thereof, kneading and extruding the mixture, Lt; RTI ID = 0.0 &gt; 650 C &lt; / RTI &gt; in air for 2 to 8 hours. The process according to claim 7, wherein the ion exchange is carried out using a 0.1 to 0.8N ammonium salt solution at a temperature of from room temperature to 120 DEG C for 1 to 6 hours each time. 8. The process according to claim 7, wherein the impregnation is carried out using a chloroplatinic acid solution at a weight ratio of liquid to solid of 1 to 3 at room temperature for 8 to 60 hours. 8. The method of claim 7, wherein the activation is carried out at 400 to 600 DEG C for 1 to 10 hours. 8. The method of claim 7, wherein platinum in the active component of the catalyst is first impregnated into the alumina and then mixed with the zeolite. From 0.1 to 0.4 wt.% (Based on the weight of the catalyst) of Pt, from 0.01 to 0.20 wt.% (Based on the weight of the catalyst) of Re and 0.05 to 0.50 wt.% (Based on the weight of the catalyst) Zeolite having a MOR structure of 60 wt.% (Based on the weight of the support), 0 to 15 wt.% (Based on the weight of the support) of ZSM-5 zeolite and 40 to 80 wt. , A catalyst for isomerization of alkylaromatic hydrocarbons. 14. The zeolite of claim 13, wherein the zeolite having the MOR structure has an anhydrous formula (in molar ratio of oxide) of 1.0 to 7.0 Na ₂ O.Al ₂ O ₃ .10 to 60 SiO ₂ , Ray diffraction pattern and the adsorbed weight ratio of n-hexane to cyclohexane is less than 1.0: [table] 15. The catalyst according to claim 14, wherein the zeolite having the MOR structure has a molar ratio of silica to alumina of 10 to 30 and a crystal size of less than 1 mu m. 14. The catalyst according to claim 13, wherein the ZSM-5 zeolite has a molar ratio of silica to alumina of 100 to 500 and a crystal size of less than 1 mu m. 14. The catalyst according to claim 13, wherein the alumina is etha-alumina or gamma-alumina. 18. The catalyst according to claim 17, wherein the alumina is gamma-alumina of high purity obtained from the hydrolysis of alkoxyl aluminum. Mixing Na-zeolite with alumina or a precursor thereof, followed by extrusion and calcination to prepare a support; Ion exchanging the support with an ammonium salt solution so that the exchanged sodium cation content of the zeolite is 30-95%, followed by drying, impregnating the support with a solution of the active ingredient metal compounds, and finally activating Lt; RTI ID = 0.0 &gt; 13. &Lt; / RTI &gt; 20. The method of claim 19, wherein the support comprises a Na-zeolite having a MOR structure, or a mixture of Na-zeolite and ZSM-5 zeolite having an MOR structure with alumina or a precursor thereof, kneading and extruding the mixture, In air at 470 to 650 DEG C for 2 to 8 hours. 20. The method of claim 19, wherein the ion exchange is carried out using a 0.1 to 0.8N ammonium salt solution at a temperature of from room temperature to 120 DEG C each time for 1 to 6 hours. 20. The process according to claim 19, wherein the impregnation is carried out using a solution of chloroplatinic acid, pyrenic acid and tin salt, at a weight ratio of liquid to solid of from 1 to 3 at room temperature for from 8 to 60 hours. 20. The method of claim 19, wherein the activation is carried out at 400 to 600 DEG C for 1 to 10 hours. 20. The method of claim 19, wherein the tin in the active components of the catalyst is first impregnated into the alumina and then mixed with the zeolite. Pd of from 0.2 to 0.8% by weight (based on the weight of the catalyst), 0.01 to 0.20% by weight (based on the weight of the catalyst) of Sn and 0.05 to 0.50% by weight of Sn (based on the weight of the catalyst) (Based on the weight of the support) of zeolite, 0 to 15 wt% (based on the weight of the support) of ZSM-5 zeolite and 40 to 80 wt% (based on the weight of the support) of alumina For the Isomerization of Alaromatic Hydrocarbons. 26. The zeolite according to claim 25, wherein the zeolite having the MOR structure has an anhydrous chemical formula (in terms of molar ratio of oxides) of 1.0 to 7.0 Na ₂ O · Al ₂ O ₃ · 10 to 60 SiO ₂ , - line diffraction pattern, wherein the adsorbed weight ratio of n-hexane to cyclohexane is less than 1.0: [table] 27. The catalyst according to claim 26, wherein the zeolite having the MOR structure has a molar ratio of silica to alumina of 10 to 30 and a crystal size of less than 1 mu m. 26. The catalyst according to claim 25, wherein the ZSM-5 zeolite has a molar ratio of silica to alumina of 100 to 500 and a crystal size of less than 1 mu m. 26. The catalyst according to claim 25, wherein the alumina is etha-alumina or gamma-alumina. 30. The catalyst according to claim 29, wherein the alumina is gamma-alumina of high purity obtained from the hydrolysis of alkoxyl aluminum. Mixing Na-zeolite with alumina or a precursor thereof, followed by extrusion and calcination to prepare a support; Ion exchanging the support with an ammonium salt solution so that the exchanged sodium cation content of the zeolite is 30-95%, followed by drying, impregnating the support with a solution of the active ingredient metal compound, and finally activating Lt; RTI ID = 0.0 &gt; 25, &lt; / RTI &gt; 32. The method of claim 31, wherein the support is a mixture of zeolite having a MOR structure, or a mixture of Na-zeolite and ZSM-5 zeolite having a MOR structure with alumina or a precursor thereof, kneading and extruding, Lt; RTI ID = 0.0 &gt; 650 C &lt; / RTI &gt; for 2 to 8 hours. 32. The method of claim 31, wherein the ion exchange is performed using a 0.1 to 0.8N ammonium salt solution at a temperature of from room temperature to 120 DEG C each time for 1 to 6 hours. 32. The process according to claim 31, wherein said impregnation is carried out using a solution of palladium chloride, perrhenic acid and tin salt, at a weight ratio of liquid to solid of from 1 to 3 at room temperature for from 8 to 60 hours. 32. The method of claim 31, wherein the activation is performed at 400 to 600 &lt; 0 &gt; C for 1 to 10 hours. 32. The method of claim 31, wherein the tin in the active component of the catalyst is first impregnated into the alumina and then mixed with the zeolite.