JPH1128363A - Catalyst composition for isomerization of dichlorotoluene and isomerization method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the activity of an isomerization catalyst by employing a catalyst composition containing mordenite with a specified size of the longer axis of crystallite, regarding a catalyst composition for isomerization which increases 2,6- and/or 3,5-dichlorotoluene isomer concentration by isomerization reaction of a mixture of dichlorotoluene isomers. SOLUTION: A catalyst composition for isomerization of dichlorotoluene (hereafter DCT) is produced by adding mordenite with 0.2 μm or shorter longer axis of crystallite. In this case, the catalyst composition containing the mordenite is preferably treated to be an acid type before the composition is used for DCT isomerization reaction. To extract effective performance of such a catalyst, it is preferable to deposit rhenium having hydrogenation activating function and to introduce silver ion into the mordenite. At the time of using the catalyst composition for a reaction, DCT which is a supplied raw material is preferably brought into contact with the catalyst in liquid phase. Rhenium is preferably added to the catalyst composition in 0.05-2 wt.% by conversion into rhenium metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dichlorotoluene (hereinafter referred to as "DCT") isomerization catalyst composition and a method for isomerizing DCT. In particular, isomerization in which a 2,6- and / or 3,5-isomer concentration is increased by an isomerization reaction from a 2,6- and / or 3,5-isomer-poor DCT isomer mixture among DCT isomers. The present invention relates to a catalyst composition and a method for isomerization.

[0002]

2. Description of the Related Art In general, DCT is obtained by dichlorination of toluene. This reaction is a highly oriented reaction, and the type of isomer obtained and the isomer production ratio are 2,4-DCT 20 to 35. %, 2,5-DCT 25-5
5%, 2,6-DCT5 to 35%, 2,3-DCT8 to
12%, 3,4-DCT 5-12%. Since 3,5-DCT cannot be obtained by this reaction,
When 5-DCT is intended, it is necessary to isomerize DCT.

[0003] Each isomer of DCT, and 3,5-DCT produced by isomerization, need to be separated in order to use it as a simple substance.

As a method for separating these isomers, the boiling points are so close to each other that they cannot be separated by distillation. For example, Japanese Patent Publication No. 1-45457, Japanese Patent Publication No. 1-4001
As shown in JP-A-6-106, etc., this can be achieved by an adsorption separation method or a combination of an adsorption separation method and a distillation method.

[0005] It is very important economically to increase the concentration of the desired isomer again by isomerizing the remaining DCT isomer after separating and removing the desired DCT isomer. Thereafter, the desired DCT isomer is separated and removed again, and this cycle is repeated.

As a method for causing such an isomerization reaction, Japanese Patent Publication No. 4-37054 and Japanese Patent Publication No. 4-37
No. 055 discloses a method using a mordenite-type zeolite (hereinafter referred to as “mordenite”), but it is industrially important to further improve the isomerization activity.

[0007]

If the activity of these conventionally known isomerization catalysts can be further improved, the reaction temperature can be lowered. When a catalyst is used in a reaction, the activity of the catalyst decreases, and an operation of increasing the reaction temperature is generally performed to compensate for the decrease in the activity. Therefore,
If the reaction temperature is lowered, the usable temperature range is expanded, and as a result, the catalyst life can be improved. From such a viewpoint, as a result of diligent studies on a method for improving the catalytic activity, it has been found that reducing the crystallite of mordenite improves the catalytic activity of the DCT isomerization reaction, and has reached the present invention.

[0008]

SUMMARY OF THE INVENTION The present invention provides a catalyst composition containing mordenite having a crystallite major axis of less than 0.2 microns and a method for isomerizing DCT using the catalyst.

[0009] The catalyst composition containing mordenite is DC
Prior to use in the T isomerization reaction, it is preferable to make it into an acid form. In order to make such a catalyst function more effectively, it is preferable to support rhenium having hydrogenation activity on the catalyst or to introduce silver ions into mordenite. The silver ion may be reduced during the reaction or may be in another compound form, but this does not cause a problem in catalytic performance. Further, when used in the reaction, it is preferable that DCT as a feedstock is brought into contact with the catalyst in a liquid phase. The coexistence of hydrogen as a feed material is preferable from the viewpoint of suppressing a decrease in catalytic activity. By dissolving hydrogen in the DCT liquid phase, the effect can be more exerted. In order to dissolve hydrogen in an effective amount of DCT, the reaction pressure is preferably set to 4 MPa or more. This will be described in detail below.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Mordenite is a zeolite having the X-ray diffraction pattern shown in Table 1.

[0011]

[Table 1]

Mordenite is available in both natural and synthetic forms.
Synthetic products are preferred for the present invention. Various methods have been disclosed for the synthesis of mordenite. For example, JP-B-47-46677 and JP-A-55-126529.
And JP-A-58-91032. The size of the mordenite crystallites cannot be said unconditionally because it varies variously depending on the composition of the reaction mixture during the synthesis, the crystallization temperature, the crystallization time, the stirring speed, etc., but the general tendency is that tetraethylammonium When an organic base nitrogen compound such as hydroxide or a surfactant such as polyethylene glycol is present, the crystallite tends to be reduced. Further, regarding the composition ratio in the reaction mixture, the size of crystallites varies in a complicated manner depending on the concentration of silica or alumina and the concentration of alkali, so it is necessary to appropriately select the optimum composition ratio. Under crystallization conditions, lowering the crystallization temperature, shortening the crystallization time, or increasing the stirring speed tends to reduce the crystallite. In any method, the major axis of the mordenite crystallite may be 0.2 microns or less for the present invention.

The size of mordenite crystallites can be easily checked with a scanning electron microscope (SEM). or,
The silica / alumina molar ratio constituting the mordenite structure is preferably 15 to 30. If the silica / alumina molar ratio is less than 15 or more than 30, the catalytic activity decreases.

When the mordenite is in the form of a powder,
For industrial use as a catalyst, molding is preferred. There are various molding methods such as a compression molding method, a kneading method, an oil drop method, and the kneading method is preferably used. As a kneading method, a binder is generally required, and inorganic oxides and / or clays are used. Alumina sol and alumina gel can be exemplified as the binder preferably used in the present invention. The amount of the binder is 5 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of mordenite on a dry basis. If moldability is poor, add an alkali metal salt such as sodium chloride, magnesium chloride, barium chloride or alkaline earth metal salt during kneading, or use polyvinyl alcohol,
It is effective to add a surfactant such as spun or rheodol.

[0015] The particle size of the compact is very important because it greatly affects the diffusion rate during the DCT isomerization reaction. The smaller the particle size, the higher the diffusion speed is preferable, but the larger the pressure loss, the more preferable an appropriate particle size. In the present invention, the particle size is preferably 0.05 to 2 mm, more preferably 0.1 to 1 mm.
It is. The compact is then dried at 50 to 200 ° C. and then fired at 350 to 600 ° C. to increase the strength of the compact.

[0016] It is preferable that the mordenite contained in such a molded article is converted into an acid form. In the case of an acid form or an ammonium ion or an organic cation which is a hydrogen ion precursor before molding, it is not always necessary to newly perform a treatment for forming an acid form, but alkali metal ions, alkaline earth metal ions, etc. Is contained, an ion exchange treatment is performed to obtain an acid form. The ion exchange treatment is performed in the case of directly forming an acid form with an aqueous solution of an inorganic acid or an organic acid,
There is a method in which ion exchange is performed with an aqueous solution of ammonium chloride, ammonium nitrate, or the like, ammonium ions are introduced, and then calcination is performed to convert the ions into hydrogen ions to obtain an acid form. Since the dealumination of mordenite tends to occur when ion exchange is performed with an acid aqueous solution, it is preferable to perform ion exchange with an ammonium salt aqueous solution.

The introduction of silver ions into mordenite can be easily achieved, for example, by ion-exchanging the mordenite compact with an aqueous silver nitrate solution. The amount of silver ions introduced is preferably 0.5 to 10% by weight, more preferably 1 to 7% by weight, in terms of metal, based on the catalyst composition. The catalyst composition containing silver ions is effective in suppressing a side reaction in the DCT isomerization reaction. Silver ions introduced into the mordenite may become metals or other compounds such as chlorides during the reaction, but do not degrade the catalytic performance.

In particular, when DCT is subjected to isomerization reaction in the presence of hydrogen in the liquid phase, rhenium is supported on the catalyst.
Rhenium functions as a hydrogenation active component, and has the effect of maintaining the catalytic activity by removing high boiling compounds that coat the catalytically active sites and poison the catalytic performance. Those usable as rhenium include perrhenic acid, ammonium perrhenate, rhenium chloride and the like. The supported amount of rhenium is 0.05 to 2% by weight based on the catalyst composition in terms of metal. More preferably, it is 0.05 to 1% by weight.

[0019] The catalyst composition thus prepared comprises 5
Dry at 0 to 200 ° C, then 350 to 600 ° C
And subjected to a DCT isomerization reaction.

The DCT isomerization reaction system may be any of a fixed bed, a moving bed and a fluidized bed, but a fixed bed flow reaction system is particularly preferable because of the easiness of operation. Reaction temperature is 2
It is 50 to 500 ° C, preferably 250 to 350 ° C.

It is preferable that the isomerization reaction of DCT is brought into contact with a catalyst in a liquid phase in the presence of hydrogen. By reacting in the liquid phase, the high-boiling compound generated in the reaction flows out of the system together with the reaction product, so that the catalyst does not cover the active sites of the catalyst and the deterioration of the catalyst over time is suppressed. It is considered that hydrogen can remove a high boiling point compound coated on the catalytically active site by hydrocracking, thereby suppressing deterioration of catalytic activity. The amount of hydrogen, expressed as a molar ratio to DCT, is 0.00
It is 5 to 0.2, preferably 0.02 to 0.1. In this case, it is particularly preferable that hydrogen be dissolved in DCT in order to exhibit its effect more. By dissolving hydrogen in DCT in a liquid phase, the reaction pressure is preferably set to 4 MPa or more, so that deterioration of the catalytic activity can be prevented.

The weight hourly space velocity (WHSV) of the 10Hr ^{-1 0.05,} preferably 5Hr ^-1 0.1.

The respective isomers of DCT thus obtained by isomerization are separated by adsorption separation and / or distillation.

These isomers are used as intermediates for pharmaceuticals and agricultural chemicals.

[0025]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited by these examples.

Example 1 Solid caustic soda (NaOH content 96.0 wt%, H ₂ O
Content 4.0 wt%, Katayama Chemical) 0.40 g, sodium aluminate solution (Al ₂ O ₃ content 18.5 wt%, NaO
H content 26.1wt%, H ₂ O55.4wt%, Sumitomo Chemical) 23.89 g, referred to as tetraethylammonium hydroxide (hereinafter "TEAOH") (TEA
55.2 g of OH content 20 wt%, H ₂ O content 80 wt%, Sanyo Chemical Co., Ltd. was added to 567 g of distilled water to form a uniform solution. This mixed solution was mixed with hydrous silicic acid (SiO ₂ content: 91.6 wt%, Al ₂ O ₃ content: 0.33 wt%, NaO
65.5 grams of H content 0.27 wt%, Nipsil VN-3, Nippon Silica) were gradually added with stirring to prepare a uniform slurry-like aqueous reaction mixture. The composition ratio (molar ratio) of this reaction mixture was as follows.

SiO ₂ / Al ₂ O ₃ 22 OH ⁻¹ / SiO ₂ 0.245 TEA / SiO ₂ 0.075 H ₂ O / SiO ₂ 35 The reaction mixture is placed in a 1000 ml autoclave and sealed, then at 250 rpm The reaction was carried out at 160 ° C. for 7 days with stirring.

After completion of the reaction, washing with distilled water and washing with water five times were repeated, followed by drying at about 120 ° C. overnight. The obtained product was mordenite having an X-ray diffraction pattern shown in Table 1. As a result of composition analysis, the silica / alumina molar ratio of this mordenite was 18.5. As a result of observing the crystallite of mordenite by SEM, the major axis of the crystallite was 0.12 μm.

Example 2 Alumina sol (Al ₂ O ₃ content: 10% by weight, colloidal alumina 200, Nissan Chemical) as a binder was added to 30 g (absolute dry basis) of the mordenite powder obtained in Example 1.
4 g, alumina gel (Al ₂ O ₃ content 70 wt%, C
3 g of ataloidAP (C-10), catalyst conversion) were added and kneaded. At the time of kneading, an appropriate amount of distilled water was added while observing the kneading state to obtain a paste-like mixture. This was made into a noodle-shaped molded body through a screen having a hole of 0.3 mmФ. After drying at 120 ° C. overnight, 550
Calcination was performed at 2 ° C for 2 hours.

Take 25 grams of the fired compact and take 10w
80 to 85 ° C. using an aqueous solution of t% ammonium chloride
For 1 hour. After repeating this ion exchange treatment five times, the resultant was washed with distilled water five times. It was dried at 120 ° C. overnight to obtain an ammonium ion exchange-type molded body.

A half of the obtained ammonium ion exchange molded product was taken and perrhenic acid was converted to rhenium metal by 6%.
It was immersed in 25 grams of an aqueous solution containing 2.5 milligrams for 6 hours at room temperature. Thereafter, the solution was drained, dried at 120 ° C. overnight, and subsequently calcined at 515 ° C. for 4 hours to convert ammonium ions into hydrogen ions, thereby obtaining a catalyst composition A containing acid-form mordenite. Rhenium contained in the catalyst composition A was 0.3% by weight.

On the other hand, the other half of the ammonium ion-exchange molded product was subjected to silver ion exchange treatment at room temperature with 37.5 g of an aqueous solution containing 0.375 g of silver nitrate in terms of silver metal. After washing with distilled water 5 times, it was dried at 120 ° C. overnight. Then, it was immersed in 25 g of an aqueous solution containing 62.5 mg of perrhenic acid in terms of rhenium metal at room temperature for 6 hours. Thereafter, the solution was drained, dried at 120 ° C. overnight, and subsequently dried for 5 hours.
Baking at 15 ° C. for 4 hours to convert ammonium ion to hydrogen ion, and catalyst composition B containing acid mordenite
I got Silver contained in the catalyst was 2.8 wt% and rhenium was 0.3 wt%.

Example 3 Solid caustic soda (NaOH content 96.0 wt%, H ₂ O
Content 4.0 wt%, Katayama Chemical) 1.22 g, sodium aluminate solution (Al ₂ O ₃ content 18.5 wt%, NaO
H content 26.1wt%, H ₂ O55.4wt%, Sumitomo Chemical) 20.88 g, referred to as tetraethylammonium hydroxide (hereinafter "TEAOH") (TEA
55.2 g of OH content 20 wt%, H ₂ O content 80 wt%, Sanyo Chemical Co., Ltd. was added to 479 g of distilled water to form a uniform solution. This mixed solution was mixed with hydrous silicic acid (SiO ₂ content: 91.6 wt%, Al ₂ O ₃ content: 0.33 wt%, NaO
65.5 grams of H content 0.27 wt%, Nipsil VN-3, Nippon Silica) were gradually added with stirring to prepare a uniform slurry-like aqueous reaction mixture. The composition ratio (molar ratio) of this reaction mixture was as follows.

SiO ₂ / Al ₂ O ₃ 25 OH ⁻¹ / SiO ₂ 0.245 TEA / SiO ₂ 0.075 H ₂ O / SiO ₂ 30 The reaction mixture is placed in a 1000 ml autoclave and sealed, and then at 250 rpm. The reaction was carried out at 160 ° C. for 7 days with stirring.

After completion of the reaction, washing with distilled water 5 times and filtration were repeated and dried at about 120 ° C. overnight. The obtained product was mordenite having an X-ray diffraction pattern shown in Table 1. As a result of composition analysis, the silica / alumina molar ratio of this mordenite was 21.3. As a result of observing the crystallite of mordenite by SEM, the major axis of the crystallite was 0.16 μm.

Example 4 The mordenite powder obtained in Example 3 was prepared in the same manner as the catalyst composition A of Example 2, and a catalyst composition C was obtained.
Also, a catalyst composition D was obtained in the same manner as the catalyst composition B.

Comparative Example 1 Solid caustic soda (NaOH content: 96.0 wt%, H ₂ O
21.3 g of tartaric acid powder (tartaric acid content: 99.7 wt%, H ₂ O content: 0.3 w)
(%, Katayama Chemical) 21.3 grams were dissolved in 587 grams of distilled water. The sodium aluminate solution (Al ₂
O ₃ content 18.5wt%, NaOH content 26.1wt
%, H ₂ O 55.4 wt%, Sumitomo Chemical Co., Ltd.) to obtain a uniform solution. This mixed solution was added to hydrous silicic acid (SiO ₂ content: 91.6 wt%, Al ₂ O ₃ content: 0.33
wt%, NaOH content 0.27wt%, Nip Seal V
N-3, Nippon Silica) was slowly added with stirring to prepare a uniform slurry-like aqueous reaction mixture. The composition ratio (molar ratio) of this reaction mixture was as follows.

SiO ₂ / Al ₂ O ₃ 30 OH ⁻¹ / SiO ₂ 0.25 H ₂ O / SiO ₂ 20 T / Al ₂ O ₃ 2.5 T: Tartrate The reaction mixture is placed in a 1000 ml autoclave. The reactor was sealed and then reacted at 160 ° C. for 3 days while stirring at 250 rpm.

After completion of the reaction, washing with distilled water and filtration were repeated five times, followed by drying at about 120 ° C. overnight. The obtained product was mordenite having an X-ray diffraction pattern shown in Table 1. As a result of a composition analysis, the silica / alumina molar ratio of this mordenite was 18.6. As a result of observing the crystallite of mordenite by SEM, the major axis of the crystallite was 0.36 μm.

Comparative Example 2 The mordenite powder obtained in Comparative Example 1 was prepared in the same manner as the catalyst composition A of Example 2, and a catalyst composition E was obtained.

Example 5 The results of conducting a DCT isomerization reaction test on the catalyst compositions A to E are shown in Table 2.

[0042]

[Table 2]

[0043]

As can be seen from Table 2, when the major axis of the mordenite crystallite is smaller than 0.2 μm, the catalyst temperature is high and the reaction temperature can be lowered.

Claims (13)

[Claims] 1. A dichlorotoluene isomerization catalyst composition comprising mordenite having a major axis of crystallites of 0.2 μm or less. 2. The catalyst composition according to claim 1, wherein the mordenite is in an acid form. 3. The method according to claim 1, further comprising rhenium.
Or the catalyst composition according to 2. 4. The catalyst composition according to claim 3, comprising rhenium and silver. 5. The catalyst composition according to claim 3, wherein rhenium is contained in an amount of 0.05 to 2% by weight in terms of metal relative to the catalyst composition. 6. The catalyst composition according to claim 1, wherein the catalyst composition contains 0.05 to 2% by weight of metal in terms of metal and silver contains 0.5 to 10% by weight in terms of metal of the catalyst composition. Item 6. The catalyst composition according to Item 5, 7. The catalyst composition according to claim 6, wherein said catalyst composition contains 0.05 to 1% by weight of metal in terms of metal and silver has 1 to 7% by weight in terms of metal of said catalyst composition.
A catalyst composition as described. 8. The method of claim 1, wherein the mordenite has a silica / alumina molar ratio of 15 to 30.
The catalyst composition according to any one of 3, 4, 5, 6, and 7. 9. A process for isomerizing dichlorotoluene, comprising contacting dichlorotoluene with the catalyst composition according to any one of claims 1 to 8. 10. The process for isomerizing dichlorotoluene according to claim 9, wherein dichlorotoluene is isomerized in a liquid phase in the presence of hydrogen. 11. The method according to claim 9, wherein dichlorotoluene is isomerized at a reaction pressure of 4 MPa or more.
0 Method for Isomerizing Dichlorotoluene 12. The process for isomerizing dichlorotoluene according to claim 9, wherein hydrogen is supplied in a molar ratio of 0.005 to 0.2 with respect to dichlorotoluene. 13. The method according to claim 12, wherein hydrogen is supplied in a molar ratio of 0.02 to 0.1 with respect to dichlorotoluene.