JPS6038331A - Isomerization of dimethylnaphthalene - Google Patents

Abstract

PURPOSE:To isomerize dimethylnaphthalene in high conversion and rate of reaction, by using a specific crystalline aluminosilicate zeolite as a catalyst, and contacting a raw material mixture containing dimethylnaphthalene with the catalyst. CONSTITUTION:A raw material mixture containing dimethylnaphthalene (abbreviated as DMN) is isomerized to obtain 2,6-DMN or 2,7-DMN. The isomerization is carried out in the presence of a catalyst containing a crystalline aluminosilicate zeolite having a molar ratio (SiO2/Al2O3) of 10-100 and X-ray lattice spacings (d) shown in the table. Preferably, the relative intensity of the peak of d(Angstrom )=3.83(I/Io) is >=70 when the peak intensity of d(Angstrom )=3.86 (Io) is taken as 100. The contact of the mixture with the catalyst is carried out preferably at 200- 500 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for isomerizing dimethylnaphthalenes.1 More specifically, the present invention relates to a method for isomerizing dimethylnaphthalenes by contacting them with a specific crystalline aluminosilicate zeolite. It's about how to do it.

BACKGROUND OF THE INVENTION Various so-called isomerization methods are known for isomerizing dimethylnaphthalenes to obtain mixtures enriched in specific isomers.

Dimethyl Natsuta 1 (hereinafter sometimes abbreviated as DMN) has 10 types of isomers, among which 2.6-D
MN and 2,7-DMN are compounds of particular industrial value. In other words, 2.6-DMN becomes 2,6 by oxidation.
- gives naphthalene dicarboxylic acid and also 2,7-DMN
gives 2,7-naphthalene dicarboxylic acid by oxidation, and polyesters containing these dicarboxylic acids as dibasic acid components can be formed into synthetic fibers and films with excellent properties.

Therefore, the so-called isomerization method is a method in which the specific DMN isomer mixture is separated from the above-mentioned mixture and then isomerized to increase the target content of the specific DMN. This is an essential process to obtain the desired results.

Many inventions have been proposed regarding the isomerization method of DMN (for example, Japanese Patent Publication No. 47-37415,
(See Publications No. 47-50622 and No. 50-37194). In these conventionally known isomerizations of DMN, it is necessary to use a limited isomer consisting of K in order to obtain the specific DMN, and the specific DMN cannot substantially be obtained from other isomers. There is a characteristic that

For example, if you want to obtain 2.6-DMN by isomerization, 1
．． You need to use 5-DMN and/or 116-DMN, and if you want to get 2,7-DMN, 1.7
-DMN and/or 1.8-DMN had to be used.

That is, the isomerization of these DMN isomers can be classified, for example, into the following series, and although mutual isomerization occurs within each series, isomerization between each series is said to hardly occur.

(I) 2+6 DMNdl +6-])] MN lot,
s-DMNQQ 2*? DMNR1w7 DMNll
, a-DMNThus, an object of the present invention is to provide a method capable of causing not only the conventionally known isomerization reaction in DMNK, but also the isomerization between each series, which was thought not to occur.

Another object is to provide a method for isomerizing DMN to target DMN at a high conversion rate and high reaction rate.

Still another object is to provide an isomerization method that causes fewer side reactions other than isomerization, and therefore produces fewer dimethylnaphthalenes. Yet another object is to provide an industrially advantageous process for producing 2.6-DMN or 2.7-DMN from a DMN mixture.

Further objects of the invention will become apparent from the description below.

According to the research of the present inventors, the purpose of the present invention is as follows: (i) The molar ratio of 5tot/A/lOs is 10 to 10
A catalyst containing a crystalline aluminosilicate zeolite characterized by: having an X-ray lattice spacing (d) of It has been found that this can be achieved by bringing the material into contact with a raw material mixture containing dimethylnaphthalenes.

According to the present invention, by using the crystalline aluminosilicate, 2.
6-D MN I 117-D MN or 1.8-D
Not only isomerization from MN to 2.7-DMN, but also 2,
Isomerization of 3- or 2.7-DMN to 2.6-DMN, 2.3-DMN or 2,6-DMN to 2. t-
Transfer of methyl groups from β-position to β-position on the same ring, such as isomerization to DMN, and transfer of methyl groups between rings can occur, and 2,6-
Alternatively, it has become possible to provide an industrially extremely advantageous method for producing 2.7-DMN.

The method of the present invention will be explained in more detail below, but first, the isomerization method will be explained about the catalyst of the present invention.

Construction and Preparation The crystalline aluminosilicate zeolite used as the active component of the catalyst in the method of the present invention has the characteristics described in (1) and (1) above. This zeolite has a high SiO*/A/ to (mole ratio) composition similar to the conventionally known zeolite ZSM-s, but the X-ray diffraction lattice spacing (d) is clearly different from that of ZSM-5. It is differentiated into

Hereinafter, in this specification, crystalline aluminosilicate zeolite may be simply abbreviated as "@zeolite".

The zeolite of the present invention has the same price as zeolite ZSM-5, but has a high SiO, /A/, 0. (molar ratio), and the ratio is in the range of 10 to 1007, preferably in the range of 15 to 70, more preferably in the range of 20 to 50.

Furthermore, the zeolite of the present invention has the characteristics of the X-ray lattice spacing shown in the table below, but according to the analysis of the present inventors, the X-ray diffraction chart of the zeolite of the present invention is ZSM-5. A detailed comparison with that of , it was found that there were some differences. One major difference is that the X-ray lattice spacing d (according to US Pat. No. 9,370,2886) gives the strongest peak of ZSM-5: 3.85 (2a = 23.14) However, in the zeolite of the present invention, its strongest peak is branched, and d = 3.86 and 3.83 (2# = 23
．． 05 and 23.25).

Another major difference is that d) = 3.00 (2θ = 29.76) of 1 in ZSM-5.
The same d(6)=
3. It is observed as a branched concave peak at O(2θ8−=29.75)K. Although this latter concave peak is not observed in all zeolites of the present invention, it is observed in most cases. Next, the X-ray lattice spacing d) of the zeolite of the present invention and its relative intensity are shown. This relative strength (
I/1. ) is a (A)= s, s a (211=
When the intensity (1,) of 2 a, os ) is 100, the relative intensity CI/Io (90) of each peak is 100 ~
60 is VS (very strong), 60-4G is S (strong), and 40-20 is M (medium).

20 to 10 is expressed in wcm).

9-Table-A 10- Furthermore, d(2)+=3.86 (2#=23.
d when the peak intensity (■, ) of 05) is set as 100
■ The relative intensity (I/I@) of the peak at = 3.83 (2θ-, as, 2s) is at least 7.0, preferably at least 75, more typically from 77 to The correlation is within the range of 80.

Furthermore, the more preferred zeolite of the present invention also exhibits unique properties in terms of chemical activity; for example, the skeleton zeolite in an activated state has a cyclohexane decomposition index ratio of at least 1. l, preferably at least 1.5, more preferably 1
．． It is 7 or more.

As used herein, the term "activated state" means that most of the alkali metal ions contained in the zeolite of the present invention immediately after synthesis are replaced with hydrogen ions according to a known method. 11- This means that 70 or more, preferably 90% or more, of the cation exchange sites based on 77 tomina of the zeolite are occupied by hydrogen ions, and this means that the zeolite in the activated state (the zeolite in such a state) (sometimes called "H-shaped zeolite") is obtained.

In general, zeolite has a roughly regulated value for its activity, particularly its acidity, depending on its molar ratio of 81°/A40°. However, one feature of the zeolite of the present invention is that it is different from ZSM having a molar ratio of y-1 diSiO,/Aω,
It shows a higher value compared to the activity of -5. In other words, if the cyclohexane decomposition activity of the standard zSM-5 is 1, the cyclohexane decomposition activity of the zeolite of the present invention having the same Ox/At*os molar ratio is:
As mentioned above, when expressed in terms of cyclohexane decomposition index ratio, 1
．． It is 1 or more, preferably 1.5 or more.

12- The present inventors speculate that this is due to the fact that the zeolite of the present invention has a higher acid strength within its pores than ZSM-5. The upper limit of the cyclohexane decomposition index ratio of the zeolite of the present invention is generally 3, preferably 2.5 or less.

The zeolite used in the present invention is to the above-mentioned Sl/A71. 4IK is sufficient as long as it has a ratio of (molar ratio) to (molar ratio) and the characteristics of the above-mentioned XII lattice spacing, and is not affected by the type of synthesis method. Among them, preferred zeolites are those whose cyclohexane decomposition index ratio is at least 1.11, preferably at least 1.5, and more preferred are zeolites synthesized by the following methods, but the zeolites shown below are more preferred. The synthesis method is just one example, and the zeolite of the present invention is not limited thereto.

131 Method A This method is a method previously proposed by the present inventors, and the details will be explained below.

That is, this method applies to Si/AtttO.

(molar ratio) of 20 to 300 crystalline aluminosilicate zeolite ZSM-5 to 1 part of wrinkled zeolite ZSM-5
This is a method of heating to a temperature between 80 and 250° C. in an aqueous solution containing an alkali metal hydroxide of 0.1 to ip corresponding to j+. This method was developed by the inventors on June 17, 1980.
The invention is specifically and detailedly explained in the specification (title of the invention: "Novel crystalline aluminosilicate zeolite and method for producing the same") filed in 1999.

ZSM-5, which is the raw material for this method, can be manufactured by the method described in Japanese Patent Publication No. 46-10064, and it is also commercially manufactured by Mobil e-Oil Fist Corporation. You can also do that. This ZSM-5 has a Si (%/A4Os molar ratio of 20 to 3001F) range, preferably 30
~200 is advantageously used for producing zeolites by process. SiO! /A/, ZSM-5 having a hemolar ratio lower than 20 is not only extremely difficult to manufacture, but also not easy to obtain. However, according to this method, S i (%/AAttOs molar ratio is 2
Not only is it possible to easily produce zeolite with a S i 01 /A4 Os molar ratio of 20 or less using ZSM-5 of 0 or more, preferably 30 or more, but also
It is surprising that such zeolites exhibit such % different activities.

Examples of the alkali metal hydroxide used in the treatment of ZSM-s (raw material zeolite) include sodium hydroxide, potassium hydroxide, lithium hydroxide, etc.15- Among them, sodium hydroxide is particularly preferred. It is. The amount of such alkali metal hydroxide used depends on the ZSM-
0.117 to 1 g per lII of s, preferably 0
．． 2 J to 0.7 N, more preferably 1i0.
It can be in the range of 311 to o, sg.

The alkali metal hydroxide is generally brought into contact with the raw zeolite (ZSM-5) particles in the form of an aqueous solution. In this case, the amount of water is not critical, and the ZSM-
5 and/or alkali metal hydroxide, etc., but usually the supplied Z S
It is sufficient that the total amount of M-s is at least a sufficient amount to be sufficiently immersed in the aqueous solution. The concentration of alkali metal hydroxide in an aqueous solution is not limited and can be varied over a wide range.
Generally, a range of 1 to 10% by weight, preferably 2 to 7% by weight is suitable.

16- The reaction is carried out between 80°C and 250°C, preferably between 100°C and 20°C.
This is done by heating to a temperature in the range of 0°C.

The reaction can be carried out until a zeolite having the above characteristics is substantially produced, and as a measure of the production, the formed zeolite/raw material zeolite) ZSM
A weight ratio of -5 can be used. That is, the reaction is carried out at a weight ratio of 10 to 80%, preferably 20 to 70%.
It is possible to continue until the amount reaches the range of 1, more preferably 30 to 60%.

The zeolite thus obtained is as described above. The chemical composition is represented by the following formula.

xM2 / 110 ・Al@OnkenySioR川用-(I)17-L ``Here, M represents an alkali metal, especially sodium, in the zeolite produced by method A, which is usually known. According to the established ion exchange method, cations such as hydrogen ions, ammonium ions, and other metal ions can be exchanged. Of course, even if the zeolite is exchanged with cations other than sodium ions, it essentially meets the requirements of the zeolite of the present invention.

In addition, in the following formula (D), X is an index of the amount of cations bonded to the zeolite IC, and in the case of the zeolite of the present invention, it is within the range of 0.5 to 4, preferably 0.9 to 3'. I can do it.

Zeolite obtained by this method K has the above-mentioned characteristics.

Compared with the known zeolite ZSM'-5 and other similar zeolites, it has the following characteristics. One of its characteristics is (cyclohexane/I
I+-hexane) adsorption ratio is abnormally large. The zeolite produced by this method has an adsorption ratio of at least 0.
．． 7, preferably at least 0.8, more preferably 0
．． It has a value of 9 or more.

(Cyclohexane/n-hexane) adsorption ratio is a value measured according to the definition described below, and for ZSM-5, all values are lower than 0.7, and those of 0.7 or higher are As far as the inventors know, it does not exist.

This adsorption ratio is a value indicating the adsorption ratio of cyclohexane to n-hexane, and the higher this value is, the larger the diameter (size) of the pores in the zeolite is. The upper limit of the adsorption ratio of zeolite according to this method AK is generally K 1.38 degrees, typically about 1.2 degrees, and this zeolite has an appropriate pore size.

19-Next, “(cyclohexane/
The definitions and measurement methods of "n-hexane)@landing" and the above-mentioned "cyclohexane decomposition index ratio" will be explained in detail.

): This (μhexane/n-hexane) rIk deposition ratio Ka per unit weight of the landed zeolite represents the weight ratio of cyclohexane to the weight of n-hexane deposited, and is a parameter that defines the pore diameter of the zeolite. , an increase in this value means that molecules with a large molecular cross-section, such as cyclohexane, will more easily diffuse into the pores.

, the adsorption amount 20- per unit weight of zeolite is measured as follows. That is, pelletized zeolite calcined in an electric furnace at 450'cK for 8 hours is accurately weighed using a spring balance of an adsorption device. Next, after evacuating the inside of the adsorption tube, cyclohexane or n-hexane was introduced in gaseous form until the temperature reached 60±2wH9, and the temperature was maintained at 1°C for 2 hours. The amount of cyclohexane or n-hexane adsorbed on the zeolite Klj can be measured from the difference in the length of the spring fist balance before and after adsorption.

The cyclohexane decomposition index ratio is the same silica/7. H in the activated state with lumina (molar ratio)! HW&1 obtained in the present invention for I ZSM-5. It is defined as the percentage of cyclohexane decomposition index 21- of the zeolite.

The cyclohexane decomposition index is calculated by calcining 10 to 20 mesh pellets of zeolite containing 50 weight percent r-alumina at 450°C for 8 hours in an electric furnace, and then filling a fixed bed reactor with a certain weight of the zeolite. By supplying cyclohexane at a weight unit hourly space velocity WH8V = 1 HR-'' (total weight basis) and hydrogen at a molar ratio of hydrogen/cyclohexane = 271 under conditions of 350°C and -atmosphere. The conversion amount of cyclohexane at this time (
(per 100 weight of feed) is called the cyclohexane decomposition index. WH8V is the following method method B. This method B is also the L* method proposed by the present inventors, and the application was filed in July 1982.
Monthly 6th K “Production method of crystalline aluminosilicate zeolite and new crystalline aluminosilicate zeolite”
An application was filed under the title of ``Ni0'', the contents of which are explained in detail in the specification of the application, and the gist thereof will be explained below.

This method B uses a full silica source! A zeolite selected from ZSM-s and zeolite F having the characteristics shown below is used as a limb zeolite 1.
1~200 per piece! The crystalline aluminosilicate zeophyte is maintained in an aqueous solution containing a small amount of alkali metal hydroxide under conditions of temperature, pressure, and time such that the crystalline aluminosilicate zeophyte is formed, having the following characteristics: (a) The molar ratio of silica/alumina is between 10 and 23-1000m, the Φ>xm lattice spacing d is as shown in Table A of the specification, and (c) the isthmus of n-1\Kisan The amount of clothing is at least o, or
This is a method for producing crystalline aluminosilicate zeolite, which is li/I.

This method B does not substantially use organic amines as in the conventional production of ZSM-5 (in other words, under conditions where organic cations derived from such organic amines are substantially absent, The essential feature is that the production of the zeolite is carried out in the presence of a zeolite previously produced by ZSM-s or method BK.

This method B uses as raw materials a silica source, an alumina source, and an aqueous solution of alkali metal hydroxide, which are usually used in the synthesis of zeolites, and a zeolite selected from zeolite (ZSM-5) and zeolite produced by method B. Zeolite can be synthesized at an extremely high yield, several times that of zeolide, and under suitable conditions, several times as high.

In this method B, any silica source that is commonly used in the production of zeolite can be used, such as silica powder, silica fluid, water-soluble silicon compounds, and glucic acid.

To explain these specific examples in detail, the silica powder is Aerosil silica.

Precipitated silica produced by a precipitation method from an alkali metal silicate such as fumed silica or silica gel is suitable, and colloidal silica may be prepared from various particle sizes, e.g.
Particle sizes of 0 to 50 microns can be advantageously used.

-1: As a water-soluble silicon compound, Sin, 1 = 5 mol, l per 1 mol of alkali metal oxide
2 to 4 moles of alkali metal silicates such as water glass and sodium monoxide.

25- Potassium silicate and the like. Colloidal silica or water glass is particularly preferred as the silica source.

On the other hand, any alumina source that is generally used in the production of zeolite can be used, such as alumina, aluminum mineral salts,
Examples include aluminates, specifically colloidal alumina and pseudoboehmite.

E1ite, r-alumina, α-alumina,! - alumina in a hydrated or hydrateable state such as alumina trihydrate; aluminum chloride, fluminiram nitrate;
Aluminum sulfate; examples include sodium aluminate and potassium aluminate, among which sodium aluminate or mineral acid salts of aluminum are preferred.

In addition, common supply of silica and alumina Aluminosilicate compounds as a source, e.g. Kaolin is a naturally occurring feldspar.

It is also possible to use acid clay, bentonite, montmorillonite, etc., and these fluminosilicates may be substituted for part or all of the above-mentioned silica source and/or silica source.

The amount of silica source in the raw material mixture of the present invention is generally in the range of 0.1 to 200 mmol, preferably in the range of 1 to 100 mmol, more preferably in the range of 5
Advantageously, the amount of alumina source is in the range from 90.01 to 20 mmol, preferably 0.01 to 20 mmol, and the amount of alumina source is generally 1.9 m (in terms of A4) starting zeolite).
The amount is preferably in the range of 1 to 10 mmol, more preferably 0.5 to 5 mmol. And, although the mixing ratio of this silica source and alumina source is not limited,
Generally, it is preferable to adjust K so that the SIOs/Al*On molar ratio is in the range of 1 to 200, preferably in the range of 5 to 100, calculated as 27- in terms of Si and hi*oa K, respectively. If this molar ratio is less than 1, the desired zeolite cannot be obtained, and if it exceeds 200, the rate of modification will be low.

As the alkali metal hydroxide, sodium hydroxide and potassium hydroxide are preferred, and each of these may be used alone or in combination.

Such alkali metal hydroxide is present in an amount of 1 to 200 mmol, preferably 5 to 200 mmol, per starting zeolite II.
It is used in amounts ranging from 100 mmol, preferably 10 to 100 mmol. In addition, for the silica source and alumina source, the alkali metal hydroxide is converted to alkali metal hydroxide/Cps + A! ,0. ) In terms of molar ratio, general KO61-10. It is preferably used in an amount of 0.2 to 5, more preferably 0.3 to 1.

The above-mentioned alkali metal hydroxide is usually used in the form of an aqueous solution, and the concentration of the alkali metal hydroxide in the aqueous solution is generally 1 to 1 mol per mol of water, based on the total amount of water in one reaction system. , preferably 5 to 50 mmol, more preferably 10 to 40 mmol.

Furthermore, in this method B, the starting zSM-5, which becomes the crystal matrix of the produced zeolite, is a known one, which is combined with an alkali metal cation and a specific organic cation that co-acidates, and is combined with a silica source and an alumina source in an alkaline aqueous solution. It can be obtained according to a known method of synthesis under hydrothermal synthesis conditions (see, for example, Japanese Patent Publication No. 10064/1983).

Zeolite 29-ZSM-5 synthesized by this known method is usually washed with water thoroughly and then
Organic cations are removed by calcination at a temperature in the range of 0°C, preferably 400-600°C. However, the 28M-5 used in this method B may be one in which such organic cations are incinerated or remain.

In addition, ZSM-5 zeolite, which is a raw material mixture, is prepared by converting some or all of the ions originally present in the zeolite into other cations such as lithium, silver, ammonium, etc., according to a known method after the above-mentioned calcination operation. Monovalent cation; Magnesium! Divalent alkaline earth cations such as calcium and barium; cobalt and nickel! Group ■ metal cations such as platinum and palladium; ■ such as rare earth metals
Furthermore, in this method B, the zeolite obtained by this method B may be used as the starting zeolite instead of the 28M-5 zeolite. The purpose of the invention can also be achieved. The form of the zeolite may be in the form of a slurry immediately after synthesis, or it may be separated from the f-liquid and subjected to a drying and calcination process. Furthermore, even if the zeolite is ion-exchanged with the metal cations as in the case of the 28M-5 zeolite, it is not acceptable.

In method B, as described above, a silica source, an alumina source, an alkali metal hydroxide, zeolite, and water are used as a raw material mixture in the proportions as described above, and the mixture is used to form a crystalline zeolite. The synthesis of zeolite is carried out by maintaining sufficient temperature, pressure and time conditions.

31- Silica source I alumina source? In addition to keeping the alkali metal hydroxide and water in the proportions described above, the silica source, alumina source, and alkali metal hydroxide in the raw material mixture were adjusted to S to, AI, O, and alkali metal-based hydroxide ions, respectively. Expressed as (0'') to St/A/, 0. = 1-200.

Preferably 5-100 More preferably 10 ~80, OR/(SiO,+AI,O,)=0.1-10.

Preferably 0.2-5, More preferably 0.3 ~l.

OH/ru0=0.001-0.1.

Preferably o, oos~ 0.05, more preferred 0.01~0.04 It is more advantageous to use a proportion that satisfies the above.

32- The temperature for the above zeolite synthesis reaction is not limited, and can be essentially the same range as the temperature conditions for conventional ZSM-s production, usually 90°C or higher,
Preferably 100 to 250°C, more preferably 120°C
Temperatures in the range ˜200° C. are advantageously used.

Furthermore, if this method B is used, the reaction rate is significantly accelerated compared to the conventional method, so the reaction time is usually 30 minutes to 7 days, preferably 1 hour to 2 days,
Particularly preferably, 2 hours to 1 day is sufficient. The pressure applied is the autoclave's autogenous pressure or higher pressure, and the autoclaving is generally carried out under the autoclave, and may also be carried out under an inert gas atmosphere such as nitrogen gas.

When synthesizing zeolite according to this method, it is possible to use the batch method described above in which the ftM material components are charged as a mixture into a reaction vessel and the reaction is carried out under the conditions described above. Alternatively, a silica source in the form of a slurry is placed in a reaction vessel containing an aqueous solution of an alkali metal hydroxide and a starting zeolite.

A continuous method may be used in which the reaction is carried out in stages while continuously feeding the alumina source.

Further, a part of the product obtained by the above method is taken out, and a new aqueous solution of alkali metal hydroxide, a silica source, and an alumina source are fed batchwise or continuously to cause the reaction to occur. You can also do it.

The zeolite formation reaction is continued by heating the VC raw material mixture to the desired temperature, with stirring if necessary, until the zeolite is formed.

After crystals have thus formed, the reaction mixture is cooled to room temperature and heated until the ionic conductivity is, for example, 5.
Wash with water until the concentration becomes 0 μU/α or less, and separate the crystals. If necessary, the crystals are kept at 50 DEG C. or higher under normal pressure or reduced pressure for 5 to 24 hours to dry the crystals.

34- Thus, according to the above method B, in addition to the silica source, alumina source and aqueous alkali metal solution normally used for the synthesis of zeolite as raw materials, zeolite)
By simply using ZSM-5 or the zeolite obtained by method B, it is possible to synthesize an amount of zeolite equivalent to several times that of zeolite (K) used as a raw material in a batch process, and several times as much under suitable conditions. It is possible to synthesize 100 times more zeolite using a continuous method.

The zeolite thus obtained contains an alkali metal ion as a cation, and can be ion-exchanged by a method known per se, for example, by treating it with an aqueous ammonium chloride solution to replace the cation sites with ammonium ions. If this is further fired, the ammonium ions can be converted to hydrogen ions in an activated state.

35- It is also possible to exchange some or all of the alkali metal ions of the obtained zeolite with other cations. Examples of ion-exchangeable cations include m-metal cations such as lithium, potassium, and silver; alkaline earth metal cations such as magnesium, calcium, and barium; and manganese, iron, cobalt, nickel, and copper.

These include divalent transition metal cations such as zinc; cations containing noble metals such as rhodium, palladium, and platinum; and rare earth metal cations such as lanthanum and cerium.

In the case of exchanging with the various cations mentioned above, it may be carried out according to a known method, and the zeolite may be contacted with a water-soluble or water-insoluble medium containing an aqueous solution containing the desired cation. Such contacting can be accomplished in either a bunch or continuous manner.

The zeolite thus obtained is lO〇 36- ~6. (10°C, preferably 300~rto.

It may be calcined at a temperature of 5 to 40 hours, preferably 8 to 24 hours, and the calcined product is also used as the zeolite of the present invention.

The zeolite obtained by this method Bk has the above-mentioned characteristics and is also a known zeolite)
Compared to ZSM-s and other similar zeolites, it has the following characteristics. One of its characteristics is that the isthmus of n-hexane has a very high value of at least 0.07 #/#.

The specific weight of n-hexane is a value measured according to the definition below. The specific amount of n-hexane deposited is a factor related to the pore volume of the zeolite, and
A large value means that the pore volume of the zeolite channel (Chan@1g) is large. However, there is naturally an upper limit to the amount of n-hexane deposited in the isthmus.
, about tfl/1, typically about o, ostt/I, preferably in the range of 0.07 to o, osII/).
- Has a specific adsorption amount of hexane.

Another characteristic of the zeolite produced by the method BK is the (2-methylpentane/cyclohexane) adsorption ratio. This adsorption ratio is a value measured by the method described below, but this zeolite is generally 1.1 to 1.6, preferably 1.2 to 1.6.
A (2-methylpentane/cyclohexane) adsorption ratio of 1.5, more preferably in the range 1.25 to 1.45 can be expected.

This (2-methylpentane/cyclohexane) adsorption ratio is a factor related to the pore size of the zeolite channel, and a large value means that molecules with large cross sections such as cyclohexane molecules 38- On the other hand, it is interesting to note that 2-methylpentane molecules, whose cross section is smaller than cyclohexane, can easily enter the channel.

Therefore, when a zeolite having a channel pore size with an adsorption ratio in the above range is used as a catalyst, it exhibits unique shape selectivity and becomes a novel catalyst of high industrial value.

Next, the characteristics of the zeolite of Method B are expressed as indicators: [Amount of n-hexane deposited in the isthmus] and [(2-
Methylpentane/cyclohexane) rIk landing ratio Landing definition and measurement method will be explained in detail.

(1) Amount of n-hexane reaching isthmus This index is calculated under certain conditions below. is adsorbed by the weight of zeolite 11 defined as the weight of n-hexane: It is measured as follows. Namely electric pine 7 39- Pellets baked in a furnace at 450°C for 8 hours Spray of adsorption device Weigh accurately using a ring balance.

Next, the inside of the adsorption tube was evacuated (Omlg) for 1 hour, and then n-hexane was introduced in gaseous form until the inside of the adsorption tube reached 50±1 gu91c, and the mixture was kept at room temperature (20±1° C.) for 2 hours. The weight of adsorbed n-hexane can be calculated from the difference in the length of the spring balance before and after adsorption.

(II) (2-Methylpentane/Schiff μhexane) Adsorption Ratio This index is expressed as the weight ratio of 2-methylpentane to the weight of cyclohexane adsorbed per Ig of zeolite under certain conditions.

The method for measuring the adsorption amount of each component is exactly the same as in the above (+) section.

The chemical composition of the zeolite obtained by the method BK is almost the same as that of the zeolite 40-lite produced by the method BK, so the explanation thereof will be omitted here.

Method C Zeolite obtained by the method described in JP-A-56-17926 Method E Zeolite obtained by the method described in JP-A-J857-123815 Zeolite described in JP-A-1-67299 These The zeolites from Method C to Method E6 have the characteristics specified in the present invention, but also have the characteristics specified in the present invention.
n-hexane) adsorption ratio is less than 0.7, generally 0
．． A point between 4 and 0.7 is one of the percentage marks. Another feature is that the amount of n-hexane deposited is 0.03~o, oe.
It has a relatively small value of l/I.

-41= of the above-mentioned specific example of the zeolite synthesis method, when the zeolite obtained by the method and the method BK is used, the isomerization activity of dimethylnaphthalene, which is the object of the present invention, is higher and more selective isomerization is achieved. This method is more preferable since it is possible to obtain a catalyst capable of causing chemical reaction.

The zeolite used in the catalyst of the present invention is one in which at least 50, preferably at least 70 of its total cation sites are occupied by hydrogen cations/+ (H). A zeolite having hydrogen cations in the above range can be prepared by a method known per se in which cations of a zeolite having a lower proportion of hydrogen cations (■+) than this range are ion-exchanged into hydrogen cations. That is, for example, hydrochloric acid, nitric acid,
It can be converted to a water-volume cation (H+) in the above range as a cationic site by immersion treatment with a mineral acid such as sulfuric acid or by exchange with ammonium ions (Mσ) and subsequent calcination.

-42+ The cations other than the hydrogen cation (H+) of s8 may be occupied by various metal cations. The analogy is Be
It may be occupied by alkaline earth metal cations such as + Mg + Ca s Sr t Da, lanthanide metal cations such as La, Ce. Also F@t Co
+ Ntl Ru+ Rh.

The zeolite may be ion-exchanged with Group 8 metals of the periodic table such as PdtOs + Ir + Pt (or these metals may be supported). When used in a chemical reaction, the catalyst surface increases as the reaction progresses, suppressing the generation of vertical substances and maintaining the activity for a longer period of time.

The zeolite of the present invention can be used in the form of a powder itself, or can be used as a molded product, for example, in the form of a pent or tablet. When used as a molded product, the content ratio of zeolite in the molded product is 1 to 100-5 in terms of M amount, preferably 1O to 90! A range of j is advantageous.

In order to further shape zeolites, refractory inorganic oxides commonly used as binders for zeolites, such as silica, alumina, silica magnesia I
Kaolin and the like are used, with alumina being particularly preferred.

When the catalyst contains a metal, the catalyst is heated at, for example, 200 to 600°C, preferably 250 to 55°C, in a reducing atmosphere (for example, a water-containing gas atmosphere) before being subjected to the reaction of the present invention.
Preferably, the reduction heat treatment is carried out at a temperature of 0°C. This reduction heat treatment may be carried out before or after the catalyst is charged into the reactor.

The zeolite produced and prepared as described above or the catalyst containing the same can be used for the isomerization of DMN, for example 1.
Isomerization of 6-DMN to 2.6-DMN, z, 7-DM
Isomerization of N to 2 + 6-, D M N, 2. ．． 3
2.6-nu of -DMN is used as a catalyst in reactions such as isomerization to 2t7-DMN.

In particular, as mentioned above, the zeolite of the present invention is unique in that it exhibits a particularly different reactivity in the DMN isomerization reaction that has not been seen with conventional catalysts. That is, conventionally, in the isomerization of DMNH, it was thought that only rearrangement of the methyl group from the a-position to the β-position or from the β-position to the α-position on the same ring was possible. However, when using the zeolite of the present invention, rearrangement of the methyl group onto a different ring (e.g. rearrangement from the 32-position to the 6- or 7-position),
and on the same Ri-Fugu, from α-position (,1-position) to α,
- position (4-position) or β-position (2-position) to β-position (3-position)
It also becomes possible to rearrange the me, thyl group to (position). However,
The zeolite of the present invention can be used in the reaction of converting 2.7-DMN, which is less useful, into 2,645-DMN, which has a high @ value, or converting 2.3-DMN into 2.6-DMN.
Alternatively, it can be advantageously used as a catalyst for 2,7-DMNK isomerization reaction.

Thus, in carrying out the method of the present invention, various DMs can be used.
A raw material mixture containing 40% by weight or more, preferably 60% by weight or more, particularly preferably 80% by weight or more of the N isomer may be brought into contact with the catalyst.
A material having a thermal equilibrium composition or less is advantageously used. For example, when trying to obtain 2.6-DMN or 2.7-DMN by isomerization, for all DMNK in the raw material mixture, ! 1
It is desirable to use a material containing 6-DMN or 217-DMN in an amount of 10% by weight or less, preferably 5% by weight or less.

The isomerization of the present invention can be carried out in either the liquid phase or the gas phase, and is generally advantageously carried out at a temperature in the range of 2G0 to SOO°C. The preferred reaction conditions differ slightly depending on whether the reaction is carried out in a liquid phase or a gas phase.

In the case of liquid phase, the temperature is 200-450°C, especially 250-35°C.
At a temperature in the range of 0°C, the weight unit hourly space velocity (WH8V) in the catalytic reaction is between 0.1 and 20, preferably! , ~
10 and the reaction pressure is from normal pressure to aokg/a! ,
Preferably 2 ko/cd -lo k1? Advantageously, it is carried out in the range /ai.

On the other hand, when the reaction is carried out in the gas phase, at a temperature in the range of 250 to 500 °C, preferably 300 to 4 o'o
~20, preferably 0.1~5 WHS V, and normal pressure ~2oky/d, preferably 1 kll/d
It is suitably carried out at pressures in the range ˜10 k41/al. In particular, when the reaction is carried out in the gas phase, ilm (N, ) or hydrogen (H,), preferably hydrogen (H2), can be introduced into the raw material mixture. Introduction of hydrogen is industrially advantageous because it can extend the life of catalyst activity.

47- The hydrogen used in this case is 0.00% per mole of raw material mixture.
A range of 1 to 100 mol, preferably 1 to 50 mol is suitable. In carrying out the isomerization reaction, the catalyst and the raw material mixture may be contacted in either a fixed bed reactor or a fluidized bed reactor, but the former is preferably used.

According to the isomerization reaction of the present invention, the use of the zeolite-containing catalyst provides the following advantages.

(1) Not only the substitution of methyl groups between the α and β positions on the same ring of the naphthalene skeleton, but also the substitution of methyl groups between the β and β positions on the same ring.
It becomes possible to substitute methyl groups between positions and between rings.

In particular, in the conventional isomerization of DMN, this does not occur, or even if it does occur, it occurs only to a very small extent, making it possible, for example, to carry out the following isomerization easily and at a good conversion rate.

2, a-DMN → 2,6-DMN or 217-0MN2
, e-DMN → 2,7-DMN 48- 2.7-DMN → 2,6-DMN (li) Therefore, in the conventional isomerization method, after the isomerization reaction,
After separating the target isomer, the isomer, which cannot undergo an isomerization reaction, was separated and removed from the system as a by-product 1 or something with no utility value.However, the isomerization of the present invention eliminates the isomerization reaction. After separating the desired isomer, other isomers are left as they are.
It can be recycled and used as raw material.

(2) Furthermore, in the past, the types of raw material isomers were limited depending on the type of target isomer. However, according to the present invention, it has become possible to obtain a wide range of DMN from a wide range of types of DMN, so the source of DMN to be used as a raw material can be arbitrarily selected. That is, DMN isomer-containing mixtures obtained from petroleum or coal fractions, DMN obtained by methylation of naphthalene or methylnaphthalene.
Any mixed eyelid containing isomers can be freely selected.

49- Yield Since the zeolite-containing catalyst of the present invention has high activity and low activity against rigid reactions such as disproportionation and demethylation, it is possible to obtain the desired dimethylnaphthalene at a high conversion rate and high selectivity.

Example-1 (a) ZSM-5 zeolite having a silica/alumina molar ratio of 71.9 was synthesized according to the method disclosed in US Patent No. 76-093.

That is, tri-n-
Propylamine and n-propyl bromide were added.

The resulting composite was filtered, thoroughly washed with water, dried in an electric dryer at 100°C for 16 hours, then at 200°C for 8 hours, and further calcined at 500°C for 16 hours under air circulation.

Next, the above ZSM-5 was mixed with 50% of an aqueous solution in which 1.5I of sodium hydroxide was dissolved in a flask.
- suspended in After this was maintained at 90°C for 3 hours with stirring, the residue 50°C was thoroughly washed with water and dried at 100°C in an electric dryer 6 for 16 hours. The weight after drying was 5.71, the silica/alumina molar ratio decreased to 39.2, and
In the X-ray diffraction pattern obtained by irradiating Cu with alpha rays, it was observed that there was a clear separation between ZSM-s and d = 3.83 (zeolite), as shown in Table A above. A-1). Furthermore, powdered zeolite person-1 is S
16 at 70°C using a wt-ammonium chloride aqueous solution.
Time ion exchange was performed. The amount of the large ammonium chloride aqueous solution used was 5 - per zeolite IJF, and this operation was repeated twice. After ion exchange, the zeolite was washed and dried as described above, and then calcined in an electric furnace at 450° C. for 8 hours with air circulation to obtain H-type zeolite (zeolite A-2).

佽) The above-mentioned zeolite A-1 was molded into a size of 10 to 20 meshes, and then fired at 450° C. for 8 hours in an electric Matsufuru furnace. Approximately 0.5 N is suspended inside the adsorption tube! The zeolite was placed on Ring-A rough cloth, and the weight of the zeolite was accurately measured based on the elongation of the spring. Next, after evacuating the inside of the suction tube, the gas holder was filled, and n-hexane or Schiff-hexane was introduced into the suction tube.

The adsorption was carried out at 20° C. for 2 hours under the conditions of s OtmH90.

The weight of adsorbate adsorbed on zeolite was calculated from the difference in spring balance length before and after adsorption. The amount of n-hexane and cyclohexane adsorbed on the zeolite is 6.8 wt% + 6.4 wtll, respectively, per weight of zeolite.
The adsorption ratio of cyclo-hexane to n-hexane was 0.94.

(e) Zeolite A-2 paste I:! -2) Alumina gel for graphing (30G mesh or less) at a weight ratio of 1
71 was added, thoroughly mixed, and molded into 10 to 20 meshes or sizes. The lacrimal material was heated in an electric Matsufuru furnace at 450'CK.
After calcination for 8 hours, 4I was charged into a fixed bed reaction tube.

After setting the catalyst bed temperature to aSO℃, cyclohexane 81
/Hr s and hydrogen at a hydrogen/cyclohexane ratio of 271 (molar ratio) was measured, and the cyclohexane decomposition index was measured and found to be 21.5.

The cyclohexane decomposition index of 28M-5, which has the same silica/alumina (molar ratio) as zeolite A-2, is 11.3 from the correlation curve in Figure 1, and therefore zeolite A-2
It can be seen that the cyclohexane decomposition index ratio of is 1.9.

Example-2 ←) Sodium hydroxide (Wako Pure Chemical Industries, Ltd. grade reagent) 1 G
, 5j dissolved in 210-pure water was added to an aqueous alkaline solution containing fluorium sulfate 16-18 hydrate (as an alumina source).
Add 3.1 g of Wako Pure Chemical's special grade reagent) and add 3.1 g of silica sol (Cafroid B-110Ls, Catalysts & Chemicals) as a silica source.
A gel was prepared by adding SO wt %) 69-41 to l.

Next, this gel was charged into a 53-inch stainless steel autoclave, and 6.9 g of *Z8M-s zeolite synthesized in Example 1-(a) was added thereto. The composition of the feed is expressed per 28M-5xg: 8101 = 50.0 mmol * M, OB = 0
．． 714 mmol NaOH=88, Omnol, and expressed in molar ratio, stow/muro=70°0H7Si+An, 0. =0.75.

OH7/H,0=o, o 1s. The charge was reacted for 6 hours at tSO 0 C autogenous pressure with gentle stirring. After removing the reactant and separating it from P, wash it thoroughly with pure water until the washing solution becomes less than 50μ0.4.
After drying at 0°C overnight and measuring the weight after fc, it was 1 G.
, Oj', and 1 for the charged 28M-5 zeolite.
．． A product weighing 5 times as much was obtained. As a result of quantifying silica alumina, silica/alumina (molar ratio) =: 23.
8, and XIs diffraction butter/ has the characteristics shown in Table A above, and in particular, it shows the strongest bi separation of d = 3.84 obtained with 54-ZSM-5 and fc (zeolite B- 1).

From this powdered zeolite) B-i, H-type zeolite (zeolite B-
2) Good results.

After forming the zeolite B-1 into a size of 10 to 20 meshes, it was heated at 450°C in an electric Matsufuru furnace for 8 hours.
Baked for an hour. Approximately 0,000 s g of zeolite was placed on a spring balance suspended in an adsorption tube, and the weight of the zeolite was precisely measured from the elongation of the spring. Next, after evacuating the inside of the adsorption tube, add n-hexane, 2-methylpentane, or cyclohexane filled into a gas skewer holder until the inside of the adsorption tube reaches 50±1ml1.
It was introduced until gK was reached. After holding at room temperature (20° C.±1° C.) for 2 hours/C, the weight of adsorbate adsorbed on the zeolite was calculated from the difference in spring balance length before and after adsorption. Zeolite) K vs. n-hexane.

The specific adsorption amounts of 2-methylpentane and cyclohexane are 0.087.9/I + o, respectively, per zeolite weight.
o s 1 g/g and 0,03411/11,
The adsorption ratio of n-hexane to cyclohexane is 1.
It was 50.

Further, the cyclohexane decomposition index ratio of zeolite) B-2 was measured according to the method described in Example 1-(c)Ic and was found to be 2.0.

Example-3 Add an equal weight of gel-like γ-alumina (300 mesh or less) to I+ type zeolite (A-2) synthesized in Example-1, mix well, and mold into a size of 10 to 20 meshes. did. 5 g of this molded product was fired at 450° C. in an air atmosphere in an electric Matsufuru furnace, and then filled into a fixed bed reaction tube.

After the catalyst bed temperature was set at 375° C., 1,5-dimethylnaphthalene was supplied at a rate of 2,5, q/HR, and hydrogen was passed in a hydrogen/B5-dimethylnaphthalene ratio of 3/1 (molar ratio). - Zeolite) B-2 synthesized in Example-2 using the same procedure as described above and HIMZ S
M-5 (1m example-1te synthesis).

The test was also carried out on commercially available HW mordenite.

The product composition 5 hours after the start of oil passing is summarized in Table 1.

This result shows that in the method of the present invention, dimethylnaphthalene can be converted into α#β of methyl groups along with normal methyl group transfer (conversion of 1,5-J column to 1,6- or 2,6-isomer).
rearrangement (conversion of the 1,5-isomer to the 1,7- or 2,7-isomer), and also the rearrangement of the methyl group to a different ring (
1,5-isomer to 1,3- or 2,3-isomer) is extremely high.

57- Table -l 58- *DMN represents the concentration of dimethylnaphthalene isomer, △
indicates the concentration difference between feed and product.

tr indicates the amount of atrophy.

Example-4 H-type zeolite (B-2) 11 synthesized in Example-2
The powder was charged into a small stainless steel reactor. 2,3-dimethylnaphthalene (Wako Pure Chemicals Special Reagent) 4JI was added to this and the mixture was sealed. After holding it at 350'CK for 6 hours, I analyzed the pull duct composition and found that it was 5.6mo.
7-2,6-dimethylnaphthalene and 4.1mo7-2,7-dimethylnaphthalene were detected.

This indicates that one of the two methyl groups on the same ring was intramolecularly transferred to a different ring.

Example-5 In this example, a continuous oil passage test in the liquid phase was conducted. H! synthesized in Example-2! Zeolite (B-2) 1071
was packed in powder form into a stainless steel fixed bed reaction tube. The catalyst bed temperature was set at 375°C, and the inside of the reaction system was flushed with nitrogen for 1 hour.
Pressurize #/5lGK to 5 and add 1,5-dimethylnaphthalene after nine! It was supplied at a rate of O1A.

Table 2 shows changes in Vcp duct composition over time.

From this result, the method of the present invention shows that the specific intramolecular methyl group transfer reaction of dimethylnaphthalene occurs even in the liquid phase.
It is also found that there is little deterioration over time.

$-2 61-

[Brief explanation of drawings]

The attached drawing shows the cyclohexane decomposition index ratio (C, D, R)
This figure shows the correlation between the silica/alumina (square ratio) of H-type ZSM-5 zeolite, which is the standard for calculating the cyclohexane decomposition index. 62-

Claims (1)

[Claims] 1, (+)SiO, /A/, 0. The molar ratio of lθ~10
0, and (1) has an X-ray lattice spacing (d) having the characteristics shown in Table 1. A method for isomerizing dimethylnaphthalenes, which comprises bringing the dimethylnaphthalenes into contact with a raw material mixture containing the dimethylnaphthalenes. 2 Wrinkled crystalline aluminosilicate zeolite has an X-ray lattice spacing of d) = 3.86, when the intensity (Io) of the peak is 100, the relative intensity of the peak of d(A) + = = s, ss 2. The isomerization method according to claim 1, wherein (1/1.) is at least 70. 1. The isomerization method described in the 1st fJi publication, wherein the crystalline aluminosilicate zeolite has a cyclohexane decomposition index ratio of at least 1.1 in the activated state. Table #The isomerization method according to item 1, wherein the contact is carried out at a temperature of 200 to 500°C. 5. The isomerization method according to item 1, wherein the raw material mixture contains at least 40% (by weight) of dimethylnaphthalenes. 6. The isomerization method according to item 1, wherein the contact is carried out in a gas phase. 7. The isomerization method according to No. Q'f14, wherein the #contact is carried out in the presence of hydrogen. 8. #The isomerization method described in Fuki 1, which is carried out in a contact liquid phase.