JPS6169738A - Isomerization of aromatic hydrocarbons of 8 carbon atoms - Google Patents

Abstract

PURPOSE:Aromatic hydrocarbons of 8 carbon atoms are brought into contact with a TSZ crystalline aluminosilicate salt in which at least a part of exchangeable cations are substituted with cations other than alkali metals to effect its isomerization. CONSTITUTION:A feedstock for isomerization containing C8 aromatic hydro carbons is brought into contact with a catalyst mainly containing TSZ crystal line aluminosilicate salt, preferably of more than 90% content, under isomerization conditions to effect its isomerization. In the catalyst, at least a part of the exchangeable cations are replaced with cations other than alkali metal, preferably H, metal of group VIII in the periodic table and the reaction conditions are 300-430 deg.C, atmospheric pressure to 30kg/cm<2> G, hydrogen/ hydrocarbon molar ratio: 0.5-5 and weight, hour, space velocity: 2-30W/H/W. The catalyst is preferably a binder-less zeolite in the form of pellets, modified cross section or hollow type.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for isomerizing aromatic hydrocarbons. More specifically, the present invention relates to a method for isomerizing C8 aromatic hydrocarbons using TSZ crystalline aluminosilicate.

(Prior Art) Crystalline aluminosilicate is generally known as crystalline zeolite, and its crystal structure in both naturally occurring and synthetic products is formed around silicon (Si), where the oxygen atoms of [1i1 It is an aluminosilicate hydrate having a structure based on a three-dimensional skeleton of AlO4 tetrahedron with 5ib coordinated at the apex and aluminum (Aj replaced with t) instead of silicon.

5i04 tetrahedron and Aβ04 tetrahedron are 4.5.6.8.
4-membered ring, 5-membered ring, 6-membered ring formed by connecting 10 or 12 members
membered ring, 8-membered ring, 10-membered ring or 12-membered ring, and these 4.
5.6.8. It is known that the basic unit is a double ring in which 10- and 12-membered rings are overlapped, and that these are connected to determine the skeletal structure of crystalline aluminosilicate.

A specific cavity exists inside the skeleton structure determined by these connection methods, and the entrance of the cavity structure is determined by 6.8.1
An opening consisting of a 0- and 12-membered ring is formed. The pores formed have uniform pore diameters, and only molecules of a certain size or less are adsorbed, and large molecules are not adsorbed because they cannot enter the cavities. Such crystalline aluminosilicates are known as "molecular sieves" due to their properties, and are used as adsorbents, catalysts for chemical reactions, or catalyst carriers in various chemical processes.

In recent years, methods that combine the above molecular sieve action and catalytic action have been intensively researched in various fields of chemical reactions. This is what is called a molecular shape selective reaction catalyst, and S, M.

As Cs1csery classifies from the functional aspect, (
1) Only specific reactants can approach the active site, (2) Only reactants with a specific shape can leave the reaction site after reacting at the active site, (3)
In a bimolecular reaction, individual molecules can freely enter and exit the reaction field, but there are three types of molecules that cannot react because the transition state is too large (Z
eolite Chemistry and Cata
lysis″＾CSMonograph 171.A
C3, Washington D, C, 1976, 6
(page 80).

This classification was made considering only the catalytic reactions inside the cavities of the crystalline aluminosilicate.

In other words, catalytic reactions on the outer surface of the crystal or on active sites near the outer surface are different from the above-mentioned catalytic action, and since all reactions occur freely, including reactions with small activation energy, the selectivity of the reaction is reduced. .

Therefore, in order to suppress such non-selective reactions on or near the outer surface of the crystal, there is a method of burying the active points by coating the outer surface of the crystal with a compound, or a method of burying the active points by coating the outer surface of the crystal with a compound, or using another method of solid acidity or alkalinity. A method of controlling the solid acidity of the active site has been considered, and the addition of silicon compounds, phosphorus compounds, magnesium compounds, etc. has been proposed.

On the other hand, there is also a method of controlling the ratio of the number of active sites with molecular shape selectivity within the crystal to the number of active sites without shape selectivity on or near the outer surface of the crystal by controlling the size of the crystal. It is being For example, when a crystal is made larger, the proportion of active sites within the crystal increases relatively, and shape selectivity becomes higher. However, according to this method, the approach and/or contact of the reactants with the active site is relatively restricted, resulting in a lower overall reaction activity. On the other hand, if the crystal is made smaller, the proportion of active sites on or near the outer surface of the crystal increases, resulting in a decrease in shape selectivity. The reaction activity increases as the reaction activity increases.

The AeOd tetrahedral charge of crystalline aluminosilicate is balanced by retaining cations within the crystal. It is a well-known theory that these cations are ion-exchanged by various methods to become a hydrogen type or a metal ion exchange type, and function as a solid acid catalyst.

In natural crystalline aluminosilicates, the cations are metal cations from Group 1 or Group Ⅰ of the Periodic Table of the Elements, but in recent years, organic cations such as tetraalkylammonium ions have been introduced. Synthetic crystalline aluminosilicates are also known, and it has been thought that the use of nitrogen-containing organic compounds as described above as an alkali source is essential for the synthesis of crystalline aluminosilicates with a high silica/alumina ratio.

However, when using nitrogen-containing organic compounds,
In addition to the disadvantage of high raw material costs, in order to use the produced synthetic aluminosilicate as a catalyst, it is necessary to remove the nitrogen-containing organic compounds present in the compound by calcination at high temperatures. This had the disadvantage of complicating the manufacturing process.

Furthermore, in the conventional manufacturing method using an amine-based organic compound such as a tetraalkylammonium compound or a primary amine of 02 to CIO as described above, the organic compound is Various dangers arise due to the potential toxicity of the organic compound or the decomposition of the organic compound, which poses problems in terms of operational safety.

Further, the use of oxygen-containing organic compounds, sulfur-containing organic compounds, etc. has also been proposed, but these cases do not solve the problems encountered when using nitrogen-containing organic compounds.

As a method to solve these problems, a method for producing crystalline aluminosilicate from an aqueous reaction mixture consisting essentially only of inorganic reaction materials has recently been disclosed (Japanese Patent Application Laid-Open No.
No. 8-45111).

It is expressed as a molar ratio of oxides, 0.8 to 1.5M2
/nO・A7!203・10~100Si02・ZH2
0 (here, M is a gold cation, n is the valence of the metal cation, and Z is θ ~ 40), and at least as shown in the following table. The present invention relates to a crystalline aluminosilicate having a powder X-ray diffraction pattern exhibiting a lattice spacing, ie, d-distance.

B? d　A)　　　・　　　■ 11.2 ±0.2 3゜ 10.1 ±0.2 3゜ 7.5 ±0.15 W.

6.03±0.1 M.

4.26±0.07 M.

3.86±0.05 V, S.

3.82±0.05 3゜3.76±0.05 3゜3.72±0.05 5゜3.64±0.05 3゜Crystal structure characterized by the X-ray diffraction pattern as described above The aluminosilicate having the following is named TSZ.

In the relative strength in the table above, rV, S, and J are the strongest, "S,"
indicates strong, "M," indicates neutral, "W," indicates weak, and rV, W, and J indicate very weak.

Furthermore, analysis of particularly accurate 2θ (θ is Bragg angle) measurement results by powder X-ray diffraction analysis, which is different from the conventional method, revealed that the crystalline aluminosilicate (TSZ) according to the invention is crystallographically simple. It is concluded that it belongs to the orthoclic system. When producing TSZ from an aqueous reaction mixture consisting essentially only of inorganic reaction materials, S i O2/A in the aqueous reaction mixture
j2203 ratio and N a 20 / S i Q 2
It is also possible to control the crystal particle size by controlling the ratio (Japanese Patent Application Nos. 58-30797 and 58-46)
No. 684).

On the other hand, isomerization reactions of aromatics using catalysts have been widely known, but because of the high industrial importance of p- or o-t-silene, the isomerization reaction of 08 aromatics is particularly important. Many improved methods have been developed for chemical reactions.

(Problems to be solved by the invention) -i. Ethylbenzene contained in the raw material has a small difference in boiling point from p- and m-xylene, and it takes a lot of energy to separate and recover ethylbenzene by distillation. Therefore, it is preferable to convert ethylbenzene to other easily separated hydrocarbons, and it is desirable to suppress the loss of xylene during this conversion reaction, and the operating conditions of the isomerization step are determined based on operating costs, etc. From this point of view, the milder the situation, the better. For this purpose, zeolites such as so-called ZSM-5 and mordenite have conventionally been used as catalysts. However, when these catalysts are used, (1) increasing the amount of ethylbenzene converted significantly increases the amount of xylene loss, (2) requiring a high reaction temperature to increase the number of converters for ethylbenzene; ■ The amount of p-xylene produced is not sufficient, and ■ The crystal size of the zeolite catalyst is only effective within a specific range, and the production of the catalyst is complicated because it requires the inclusion of multi-component metals. This has many drawbacks, such as the high cost of the catalyst.

As a result of intensive studies to solve the above-mentioned drawbacks, the present inventors discovered that the above-mentioned TSZ is particularly effective in the conversion reaction of C8 aromatics, and arrived at the present invention.

, Therefore, the first objective of the present invention is to provide an efficient method for the conversion of C8 aromatics.

A second object of the present invention is to provide special reaction conditions for the conversion reaction of C8 aromatics using TSZ.

A third object of the present invention is to provide a process for the isomerization of C8 aromatics using a shaped catalyst containing TSZ.

1. Structure of the invention (means for solving the problem) As described above, the isomerization raw material containing an aromatic hydrocarbon having 8 carbon atoms is converted into a catalyst containing TSZ crystalline aluminosilicate as a main component. was achieved by contacting the TSZ crystalline aluminosilicate under conversion conditions with a catalyst in which at least a portion of the exchangeable cations are replaced by other cations than an alkali metal.

The aromatic hydrocarbon having 8 carbon atoms in the present invention is one that is subjected to isomerization, and specifically means ethylbenzene and xylene.

That is, conventionally, in order to obtain as much xylene as possible from a raw material containing ethylbenzene and xylene, this raw material is used to isomerize xylene using ZSM-5 or mordenite as a catalyst, and at the same time convert ethylbenzene into other molecules. There is. It is not clear why the conversion of ethylbenzene can be increased without increasing the loss of xylene when TSZ crystalline aluminosilicate is used as a catalyst in this case, but T
It is said that one of the reasons for this is that the crystal structure of SZ crystalline aluminosilicate is monoclinic, unlike that of conventional crystalline aluminosilicate, as described above. This is not unreasonable considering that there is no change even if the cations of TSZ are exchanged (Japanese Unexamined Patent Publication No. 58-45111). However, as in the present invention, C6 aromatic hydrocarbons are It is a surprising fact that it has a remarkable effect on the isomerization reaction.

The TSZ crystalline aluminosilicate according to the invention is characterized by an X-ray diffraction pattern obtained by conventional powder X-ray diffraction. That is, 2θ=14°7° (d=6.0
3 persons) diffraction line is a single line (Single), 2θ=23” (d=3.86 persons) and 2θ=
The crystal structure differs greatly from that of conventionally proposed crystalline zeolites in that the two diffraction lines at 23.3° (d=3.82) are clearly separated. Such a specific X-ray diffraction pattern is due to the change of the substituted cation of the synthetic aluminosilicate, especially to the hydrogen ion type, 5i02/A/! Even if the 203 ratio changes, etc., the lattice spacing does not undergo a significant change. Such a method of synthesizing TSZ was disclosed in Japanese Patent Application Laid-open No. 1983.
-45111.

On the other hand, when zeolite catalysts are used industrially, e.g. in fixed beds of gaseous and liquid feedstocks or in fluidized bed operations such as catalytic cracking, they are used as particles with a certain shape, e.g. in the form of pellets. Supplied in particles, small spherical particles. Generally, the strength of molded particles is determined by the size of the constituent particles,
It changes depending on the packing structure, the coordination number of the particles, the shape of the particles, etc., and further changes depending on the volume and radius of the pores formed.

In particular, shaped zeolite catalysts are aggregates of crystal particles with various shapes, and the pore structure is a so-called binary pore structure, consisting of micropores possessed by the crystal particles themselves and macropores formed between the crystal particles. Ru. However, such crystal grains usually have almost no bonding force, so they are molded using some kind of binder to give the pellet strength. In this case, the gas phase reaction is generally carried out at a large space velocity, and in the liquid phase reaction of heavy oil, diffusion from the catalyst surface is limited, so almost only the outer surface of the catalyst particles is used (in the US No. 3,966.644 shows that this diffusion limit is about 1/120th of an inch).
Therefore, it is desirable to increase the surface area of the active zeolite catalyst as much as possible. Such conventional requirements have been met by the development of binderless zeolite consisting essentially of crystalline aluminosilicate (Japanese Patent Application No. 58-39721).
It can be solved by Therefore, in the present invention, it is preferable to include TSZ crystalline aluminosilicate in the binderless zeolite.

The outline of the manufacturing process for such a binderless zeolite catalyst is as follows.

■Process of manufacturing raw material powder ■Process of manufacturing aluminosilicate gel for binder ■Process of kneading raw material powder and binder and molding ■Process of drying or firing molded product ■Process of hydrothermal treatment of molded product This invention The raw material powder used herein means a crystalline aluminosilicate prepared in advance. As the crystalline aluminosilicate prepared in advance to be used as such raw material powder, TSZ crystalline aluminosilicate may be used alone, or one selected from ZSM-5, mordenite, ferrierite, etc. It is also possible to use a mixture of more than one species. The pre-synthesized TSZ crystalline aluminosilicate used here is sufficient as an unfired synthesized one, and furthermore, it does not need to be in a perfect crystal form, but is simply pre-crystallized. Aluminosilicates that exhibit an X-ray diffraction pattern close to amorphous can also be used. Especially small particle size TS
When Z crystalline aluminosilicate is used, a binderless zeolite with excellent activity and strength can be obtained, which is preferable.

Further, in the production of the raw material powder, a mineralizing agent such as NaCl may be added for the purpose of modifying the fluidity of the gel.

TSZ crystalline aluminosilicate is a silica source, an alumina source,
containing an alkali source, water and a neutral salt of an alkali metal,
The aqueous reaction mixture is prepared from an aqueous reaction mixture consisting essentially of inorganic reactants, and the composition of the aqueous reaction mixture, expressed in molar ratios of oxides, is as follows:

S i O, : / A ji! 203 1
0~130NazO/S i02 0.01-~0
．． 5(NazO+M2/nO)/5i02 0.03~0.3 H20/(Na20+M2/no)150~800 x-/5to2 o, 01~20 In the above formula, M is the group 1 and a metal cation selected from group 1, preferably lithium, sodium, barium, calcium and strontium, where n is the valence of the metal cation and X- is the salt of the precipitation aid and/or mineralizer; The ions 0M2/no and Na2O are free M2/no and Na2O, respectively, and are generally in the form of specific acid salts, such as aluminates, silicates, etc., which are effective in hydroxide and zeolite synthesis. be. Moreover, the above-mentioned "free Na2O" can be adjusted by adding aluminum sulfate, sulfuric acid, hydrochloric acid, nitric acid, or the like.

TSZ crystalline aluminosilicate can be produced by heating and maintaining the aqueous reaction mixture prepared as described above at the crystallization temperature until crystals form. The manufacturing conditions are, for example, about 20°C to about 230°C under self-pressure and about 1
This is achieved by maintaining the temperature for 0 hours to 10 days.

Furthermore, the TSZ crystalline aluminosilicate has a composition ratio of 5i02/A42203 and N of the above aqueous reaction mixture.
By changing the a2O/5i02 molar ratio, the crystal grain size of the produced crystalline aluminosilicate changes. That is, S io,7/Al2O3%JI of the aqueous reaction mixture
N by changing the Na2O/5i02 molar ratio according to the z ratio.
a2O/Aj! After making sure that the 203 molar ratio is the same, 5i02/Aj! When the molar ratio of 203 is changed, crystalline aluminosilicate having substantially the same crystal grain size is produced. On the other hand, Na2O/Aj! By varying the 203 molar ratio in the range of 1 to 15, crystalline aluminosilicate having a desired grain size in the range of about 0°1 to about lOμ can be produced.

In the present invention, a binderless zeolite can be produced by kneading a raw material powder and a binder prepared in advance and placing a molded product under crystallization conditions. The mixing ratio of the crystalline aluminosilicate prepared in advance and the binder is preferably 30 to 70% by weight of the former and 70 to 30% by weight of the aluminosilicate gel as the binder. In this case, even if the binder itself for producing the molded body does not have a crystallizable composition,
Although it is possible to partially crystallize the binder by placing it under appropriate conditions, it is important to keep the binder itself in a composition that can be crystallized from the beginning of forming the molded body, which improves the manufacturing conditions for binderless zeolite as a whole. This is preferred because it can be mild and uniform crystals can be obtained.

The aluminosilicate gel used in the present invention can be obtained by filtering the aqueous reaction mixture, which is a precursor of the TSZ crystalline aluminosilicate, after aging for a certain period of time, to crystallize the aluminosilicate gel or molded product. After washing until the composition is within a range that does not cause excessive crystallization, thoroughly drain water to reduce the moisture content (dry basis) to approximately 6.
It is preferable to adjust the amount from 5% by weight to about 95% by weight so as not to require the addition of water during kneading.

In the present invention, the crystalline aluminosilicate prepared in advance and the aluminosilicate gel obtained as described above are adjusted to a composition ratio that allows at least crystallization of the molded product, and then kneaded and molded. After that, the ratio of water and molded body is set to a value that allows crystallization without a mineralizing agent, and by hydrothermal treatment,
It is preferable to crystallize the aluminosilicate gel as the binder, which is initially amorphous. The composition of the molded body in this case is expressed by the molar ratio of oxides, Na
2O/Al2O31,2~4.0 5i02/ALz03 10~100Na20/5
i02 is preferably 0.02 to 0.15, particularly Na2O/Al2O31,5 to 3.0 3i02/An! 203 20~8ONa20/
5i02 0. 03~0. It is preferable to set it to 12.

The amount of alkali in the molded body is an important factor for producing the binderless zeolite in the present invention. That is,
If the amount of alkali is small, crystallization may take a long time,
It may remain amorphous. In addition, the alkali deficiency can be added externally to cause crystallization, but in this case crystallization tends to occur from the surface of the molded product (crystallization of the molded product does not proceed uniformly, causing powdering). This is not preferable because it may lead to a decrease in the strength of the molded product.

On the other hand, if there is too much alkali IJ ffi, the time required for crystallization will be shortened, but it may grow into large crystal grains, weakening the strength of the molded product, or forming other crystal phases. I don't like it.

Furthermore, an important factor for producing the binderless zeolite in the present invention is the ratio (weight ratio) between the solution and the molded body during hydrothermal treatment.

As the hydrothermal reaction progresses, the composition of the molded body or binder becomes close to that of zeolite, and Na 20
/ A 1203 molar ratio approaches 1.

Therefore, the excess Na comes out into the solution as the hydrothermal reaction progresses. Therefore, if the composition of the molded body is constant, the smaller the amount of solution, the higher the alkaline concentration of the solution.
If the amount of solution is large, the alkalinity of the solution will be relatively dilute. Therefore, the composition of the molded body should be within the above range, and the weight ratio of H20/molded body should be 10 or less, preferably,
By setting the number in the range of 1 to 9, binderless zeolite can be easily synthesized without adding a mineralizing agent, particularly a sodium salt, during hydrothermal treatment.

The binderless zeolite obtained in this way, which consists essentially only of crystalline aluminosilicate, has a sharp distribution of macropores formed between crystal grains in the thousands, and has a strength that can withstand practical use. has.

The pore radius and pore volume of the binderless zeolite catalyst substantially made of crystalline aluminosilicate according to the present invention can be adjusted by adjusting the manufacturing method. The total pore volume measured by gender is 0.3 cc/g or more, the pore radius is 75 to 75,000, and 25% or more of the pore volume is ±20% of the average pore diameter of the radius. It is preferable that the crystal grains be comprised of relatively small crystal particles.

When synthesizing a binderless zeolite catalyst, the shape of the solid used in the hydrothermal reaction is not particularly limited, but from the viewpoint of ease of molding or efficiency when used as a catalyst, a pellet type is particularly preferred. , variant type (P
hollow cylindrical type
ow tube), and the size is preferably about 1.5 m in outer diameter for ease of handling.

Although a method for measuring the radius of secondary pores in binderless zeolite is not necessarily established, the average radius can be estimated by the so-called mercury intrusion method. In the present invention, the radius indicating the cumulative pore volume value of 1/2 of the total pore volume obtained by this mercury intrusion method is
Defined as the average pore radius, the size of the pore radius is not only related to the actual catalyst surface area, but also affects the diffusion rate of reacting molecules and generated molecules, from the viewpoint of catalytic activity. It is important because

In the present invention, TSZ synthesized as described above
A binderless zeolite catalyst containing a crystalline aluminosilicate and/or substantially TSZ crystalline aluminosilicate (hereinafter, unless otherwise specified, both are collectively referred to as rTs
(abbreviated as ZJ) is used in the isomerization reaction of C8 aromatic hydrocarbons.

In this case, the TSZ catalyst can be used in a fixed bed or in a fluidized bed, but is generally used in a fluidized bed. Therefore, in this case it is particularly preferable to use the binderless zeolite.

The conversion conditions for the isomerization reaction of the present invention are one temperature: 250'C
~500°C1 Pressure: Atmospheric pressure ~60kg/cI111 Flow rate is expressed in weight hourly space velocity (WHSV) 0°5~5
0W/H/W, hydrogen/raw material hydrocarbon ratio: 0 to 10 mol 1 mol, more preferably temperature: 300°C to 43°C
0°C, pressure: atmospheric pressure ~ 30 kg/cut, flow rate expressed in weight hourly space velocity (WHSV) 2 ~ 30 W/H/W,
Hydrogen/raw material hydrocarbon ratio: 0.5 to 5 moles to 1 mole.

When using a raw material containing ethylbenzene as a C8 aromatic hydrocarbon, not only can ethylbenzene be isomerized to xylene with higher efficiency than ever before, but also the p-xylene equilibrium attainment rate is high. In particular, an isomerization process advantageous for the production of paraxylene can be achieved. Moreover, compared to conventional catalysts, the loss rate of xylene can be suppressed to a low level even under conditions where ethylbenzene can be sufficiently removed.

The isomerization method of the present invention having the above-mentioned characteristics can be achieved under relatively mild conditions, and in particular, the reaction temperature can be lowered than in the conventional case, so the energy cost required for equipment and operation can be reduced. It can also be reduced.

(Effects of the Invention) According to the present invention, ethylbenzene can be converted into industrially useful xylene and other hydrocarbons with high efficiency, and at the same time, xylene can be isomerized, and the loss rate of xylene is This method is extremely effective especially when selectively recovering xylene from hydrocarbon raw materials containing ethylbenzene and xylene.

The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited thereto.

/″′ /″′ (Example) 25.0 g of aluminum sulfate 18 in t62.3 g of water
Dissolve the water salt and add 16.5 g of concentrated sulfuric acid (95% by weight)
An aluminum sulfate solution was prepared by adding (A solution),
Separately, 118.3 g of water and 234.0 g of Japanese Industrial Standard No. 3 water glass (Na20 9.32% by weight,
5io2 28.9% by weight: hereinafter abbreviated as No. 3 water glass)
A mixed solution was prepared (solution B). Furthermore, a solution was prepared by dissolving 71.8 g of sodium chloride in 463.4 g of water (solution C). An aqueous reaction mixture was prepared by simultaneously adding and mixing the A solution and the B solution to the cf4 solution while stirring. The composition of this reaction mixture is expressed as a molar ratio of oxides. I
Na20-A1203-30, O5i02・1334
H20't? there were.

The resulting aqueous reaction mixture was charged into a SUS autoclave, heated and maintained at 180"C under autogenous pressure for 40 hours. The crystallized solid product was separated by filtration, washed with water, and then dried at 110"C.

When a sample of this solid product was subjected to chemical analysis, it was found that Na
2O; 3.13% by weight, Ag2O3; 5.03% by weight,
5i02; 83.6% by weight, H2O.

A chemical composition of 8.2% by weight was obtained. This was expressed as the molar ratio of oxides as follows.

1.02Na20-Ag2O3.2B,2SiO)12.5H20 This product was confirmed to be TSZ crystalline aluminosilicate by X-ray analysis.

50 g of TSZ powder produced by the method of Preparation Example 1 and 380 g of silica alumina wet gel (water content 86.8%
) was kneaded in a kneader while drying until the moisture content reached a moldable level, and molded into pellets with an outer diameter of approximately 1.5 fins in an extruder.

The silica alumina wet gel used here was an aluminum sulfate aqueous solution containing 25.0 g of aluminum sulfate, 13.0 g of 95% sulfuric acid, and 162.3 g of pure water, 234.0 g of No. 3 water glass, and a water glass aqueous solution containing 118°3 g of pure water. of,
It was prepared by adding it to 463.4 g of pure water and filtering it.

After drying the pellets at approximately 110°C for 5 hours, a portion was separated and chemically analyzed, and it was found that 5i02 was 85°3% by weight, A
g2o3 is 4.98% by weight, Na2O is 7.05% by weight
, scorching heat at 900℃/! The amount was 2.65% by weight.

After further baking at 600°C for about 3 hours, 70g was collected and placed in a SUS autoclave with 60.5g of sodium chloride and 867g of pure water, and heated at 180"C for 4 hours.
Crystallization was carried out for 0 hours. After the temperature was lowered, the pellet was taken out from the autoclave, washed, dried, and subjected to powder X-ray diffraction analysis, which confirmed that it was a TSZ crystalline aluminosilicate.

In addition, electron micrographs show that most of the material is crystalline.
It was revealed that the silica alumina wet gel turned into TSZ crystalline aluminosilicate.

Enemy +1,'
-+ In order to ion-exchange the sodium ions of the TSZ crystalline aluminosilicate obtained in Preparation Example 1, an ion-exchange operation was performed at 80°C for 1.5 hours using a 5% ammonium chloride (NHdCl) solution. . This operation was repeated four times to prepare ammonium (NH4) type TSZ crystalline aluminosilicate powder.

Next, this NHJ type TSZ crystalline aluminosilicate powder is separated and used, mixed with a separately prepared alumina binder at a ratio of 7:3 (weight ratio after firing), water is added, and kneaded. After that, it was molded into a pellet with an outer diameter of about 1.5 mm using an extrusion molding machine. After drying this, at 600℃
A catalyst containing a hydrogen (H) type TSZ crystalline aluminosilicate was prepared by firing for a period of time (hereinafter referred to as catalyst A).

The above NH,j-type TSZ crystalline aluminosilicate powder is separated and treated with platinum ammine complex ions (e.g. p t (
Platinum (Pt) -77%
Ni (NH4) type TSZ crystalline aluminosilicate powder 11! ! ! did. This Pt-NH4 type TSZ was mixed with a separately prepared alumina binder at a ratio of 7:3 (weight ratio after firing), water was added and kneaded, and an extrusion molding machine was used to form pellets with an outer diameter of approximately 1.5 mm. It was molded into. This was dried and then calcined at 600° C. for 3 hours to prepare a catalyst containing platinum (Pt)-hydrogen (H) type TSZ crystalline aluminosilicate (hereinafter referred to as catalyst B).

When the platinum content of catalyst B was analyzed, it was found to be 0. It was 81% by weight.

Sodium-type binderless TS obtained in Preparation Example 2
60 g of Z crystalline aluminosilicate pellets were mixed with 5 M% ammonium chloride solution per tg of TSZ pellets.
The ion exchange treatment was performed a total of four times at 80° C. using 1.0 mf each (each treatment time was 1° and 5 hours). The ion exchange product was then washed with water and dried at 110°C to prepare a pellet of binderless TSZ crystalline aluminosilicate of ammonium (NH4) type. As a result of chemical analysis, it contained less than 0.01% by weight of Na2O.

Also, 5i02/Aj! The molar ratio of 203 was 28.9.

NH4 type binderless TSZ obtained as above
A hydrogen-type catalyst was prepared by taking 10 g of the product and calcining it at 600° C. for 3 hours (hereinafter referred to as catalyst C).

In addition, 10 g of the above NH, a-type binderless TSZ was taken out and treated with a 1N Ni (NO3)2 solution at 80°C for 1 hour, washed with water, and dried for 60 minutes.
It was calcined at 0°C for 3 hours to obtain a binderless TSZ crystalline aluminosilicate catalyst containing 0°C and 85% by weight of Ni (hereinafter referred to as catalyst).

Furthermore, 10 g of the NHJ type binderless TSZ described in L was collected and platinum ammine complex ions (e.g., Pt (Nf(
3) Immerse in an aqueous solution containing 42+) at about 70°C for about 20 hours, then separate the solids (pellets) and wash with water.
After drying at 10° C., the mixture was calcined at 600° C. for 3 hours to prepare a binderless TSZ crystalline aluminosilicate catalyst containing platinum (hereinafter referred to as catalyst E). In addition, apart from this, palladium (Pd) complex ions (for example, Pd
A binderless TSZ crystalline aluminosilicate catalyst containing palladium was prepared in the same manner as the cleavage method of catalyst E, except that an aqueous solution containing (NH3)4z+) was used (hereinafter referred to as catalyst F). .

14.3 g of aluminum sulfate was dissolved in 390 g of pure water, and 8.7 g of concentrated sulfuric acid (95% by weight), 51.4
g of tetrabropylammonium phyto(TPAB)
r) and 39.0 g of sodium chloride were added to prepare an aluminum sulfate solution. This aluminum sulfate solution was mixed with a mixed solution of 77.0 g of water and 156.0 g of No. 3 water glass with stirring, and the molar ratio of the oxides was 4.5 (TPA) 20.4. ONa2O・AN2
03 ・ 35. OS i02・1477H
An aqueous reaction mixture with a composition of 20 was obtained. The aqueous reaction mixture was charged into a SUS autoclave and heated to 160° C. for 20 hours at autogenous pressure. The crystallized solid product was separated by filtration, washed with water and dried at 110°C. A sample of this solid product was subjected to chemical analysis and found to be (TPA)20.

11.8% by weight, Na2O; 1.80% by weight, Al2O
3; 4.62% by weight, 5i02; 75.4M%, H2
A chemical composition of O; 6.36% by weight was obtained. This was expressed as the molar ratio of oxides as follows.

0.67 (TPA)20・0.64Na20-Aj2203・27.7Si02・7.8H20 After calcining this product at 540°C for about 3 hours, it was subjected to X-ray analysis and confirmed to be ZSM-5 zeolite. did.

The thus obtained ZSM-5 zeolite powder was subjected to ammonium ion exchange in the same manner as in the preparation of catalyst A described in Preparation Example 3, then molded using an alumina binder, dried and calcined, Hydrogen (H) type ZSM-
A catalyst containing 5 was prepared (hereinafter referred to as catalyst G).
.

For the catalysts A, B, C, D, E and F of the present invention described above, a raw material liquid containing ethylbenzene and xylene having the composition shown in Table 1 below was supplied using a fixed bed flow reactor, The reaction activity was tested. The reaction conditions for the test were temperature 3.
Range from 00°C to 340°C, pressure cuff kg/-instrument pressure,
Weight hourly space velocity (WHSV) 4.3W/H/W to 1
5.6 W/H/W range, ratio of hydrogen to raw material liquid (H
2/HC) ranged from 1.0 to 3.3 mol per mol.

The conditions and reaction results for each test are shown in Tables 1 to 4 below.

:l: ro ning η 3 box mi engineering p size 0-÷(
5) 1 soft, iE O＼6 Sashu a everyone-
In addition, various abbreviations and ratios used in the table have the following meanings.

NA: Non-aromatic hydrocarbon B having 1 to 9 carbon atoms
: Benzene T : Toluene EB : Ethylbenzene p-X : Baraxylene m-X : Meta-xylene ox : Ortho-xylene ET : Ethyltoluene TMB, :) Limethylbenzene DEB Nidiethylbenzene EX : Ethylxylene AlO+ : DEB and EX Aromatic hydrocarbons with carbon atoms of 10 or more, excluding (AR) [X]: Concentration of xylene 3 isomer in raw material liquid [X]
: Concentration of xylene 3 isomer in product (EB): Concentration of EB in raw material liquid (EB): Concentration of EB in product P (AR): Total number of moles of aromatic hydrocarbons in raw material liquid ( mole)
(AR): Total number of moles of aromatic hydrocarbons in the product (mol)
However, all concentrations are weight %.

These results show that each catalyst has excellent xylene isomerization activity and ethylbenzene conversion activity.

・-, 7 to 10 This test example uses ethylbenzene (p
-X (containing 0.82% by weight) was used as a raw material for the reaction. The ethylbenzene conversion activity of Catalyst C and Catalyst G (Comparative Example) obtained in Catalyst Production Examples was tested using a fixed bed flow reactor. The test conditions and results are shown in Table 5 below.

Below is the margin Table 5 Reaction test example 7 8 9 10 Reaction conditions Temperature ('C) 300 340 300
340 pressure (kg/cjG) 0 0
0 0WH5V (W/H/W) 6.9
6.9 6.9 6.9H2/HC (molar ratio)
3.0 3.0 3.0 3.0 Product composition (wt%) NA O,762,790,171,
06B 10.87 18.66
4.38 11.45T O,45
2,410,090,53Ef% 7
0.21 53.51 86.57 71.08p-x
O,420,730,400,40
m-X O, 491,070,350
,42o-X O,220,5B
0.14 0.19ET O,4
50,740,060,50T Gate B
O,010,010,010,01DEB
15.87 19.04 7
．． 38 13.73EX
O,120,290,010,13A l □ +
0.16 0.71 0.47
0.56P-X equilibrium attainment rate (χ)83 91
72 79 Xylene loss rate (χ) -38-19
0-9-23EB conversion rate (χ) 29.2
4B, 5 12.7 28.3 However, is ZSM-
The value is based on the 5 zeolite content.

From these results, it is clear that Catalyst C of the present invention has a higher ethylbenzene conversion activity than Catalyst G of the comparative example, and also produces a larger amount of useful xylene.

AntijJ Experiment 1 Using a fixed bed flow reactor, the reaction activity of Catalyst E obtained in Catalyst Production Example was tested. In the test, the isomerization reaction was performed continuously for about 20 hours under the conditions of Reaction Test Example 5, and then the temperature was lowered and the reaction temperature was set at 310°C. After testing the reaction activity of Catalyst E at a temperature of 310°C, the temperature was raised in steps of approximately 7°C to 330°C. The test time at each reaction temperature was approximately 16 hours. Pressure, WH5V and H2/HC are 7 pupils/cdG, 15.5-16 respectively
．． Ethylbenzene 18.46% by weight, paraxylene 10% under the conditions of 0W/H/W and 1.0-1.1mol 1mol.
A raw material liquid having a composition of 66% by weight, 56.82% by weight of meta-xylene, and 13.27% by weight of ortho-xylene was used.

The ethylbenzene conversion rate, xylene loss rate, and xylene equilibrium attainment rate obtained in this test are shown in FIG. This result shows that xylene isomerization and conversion removal of ethylbenzene can be achieved with a small amount of xylene loss. Moreover, it has been demonstrated that the catalyst of the present invention has an excellent ability to maintain activity.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the ethylbenzene conversion rate, the xylene loss rate, and the xylene equilibrium attainment rate in the isomerization reaction of the present invention.

Claims (1)

[Scope of Claims] 1. An isomerization raw material containing an aromatic hydrocarbon having 8 carbon atoms is replaced with a catalyst containing TSZ crystalline aluminosilicate as a main component, and the TSZ crystalline aluminosilicate is exchanged. A method for isomerizing C8 aromatic hydrocarbons, the method comprising contacting the C8 aromatic hydrocarbons with a catalyst in which at least a portion of the cations are substituted with cations other than an alkali metal under conversion conditions. 2. The method for isomerizing C8 aromatic hydrocarbons according to claim 1, wherein the content of the TSZ crystalline aluminosilicate is 70% or more. 3. The method for isomerizing C8 aromatic hydrocarbons according to claim 2, wherein the content of the TSsZ crystalline aluminosilicate is 90% or more. 4. C8 aromatic hydrocarbons according to claim 1, wherein the substituted cation is at least one element selected from hydrogen and a Group VIII metal of the Periodic Table of the Elements. isomerization method. 5. Conversion conditions: Temperature: 250°C to 500°C, Pressure: Atmospheric pressure to 60kg/cm^2 instrument pressure, Hydrogen/Feedstock hydrocarbon (1 mol): 0 to 1010 Space velocity (WHSV): 0. 5 to 50 W/H/W, the method for isomerizing C8 aromatic hydrocarbons according to claim 1. 6. Conversion conditions are temperature: 300℃~430℃, pressure: atmospheric pressure~30kg/cm^2 instrument pressure, hydrogen/feedstock hydrocarbon (mol/mol): 0.5~5 weight hourly space velocity (WHSV). ): 2 to 30 W/H/W. The method for isomerizing C8 aromatic hydrocarbons according to claim 5. 7. The method for isomerizing C8 aromatic hydrocarbons according to any one of claims 1 to 6, wherein the catalyst is a pellet-type, irregular-shaped, or hollow-type molded body. 8. The method for isomerizing C8 aromatic hydrocarbons according to claim 7, wherein the pellet-type, irregular-shaped or hollow-type molded body is a binderless zeolite.