JP3509589B2 - Catalyst composition for isomerization of dichlorotoluene and isomerization method - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Generally, DCT is obtained by dichlorination of toluene. This reaction is a reaction having a strong orientation, and the kind of isomers obtained and the ratio of isomers produced are 2,4-DCT 20 to 35. %, 2,5-DCT 25-5
5%, 2,6-DCT5-35%, 2,3-DCT8-
12% and 3,4-DCT 5-12%. 3,5-DCT cannot be obtained by this reaction.
When 5-DCT is intended, it is necessary to isomerize DCT.

Each isomer of DCT, and further 3,5-DCT produced by isomerization, must be separated in order to be used as a simple substance.

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

It is economically very important to increase the concentration of the desired DCT isomer again by the isomerization reaction of the remaining DCT isomer after the desired DCT isomer has been separated and removed. Then, 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.
Although a method using a mordenite type zeolite (hereinafter referred to as "mordenite") is disclosed in Japanese Patent 055, etc., 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 in order to compensate for the decrease in the activity, an operation of increasing the reaction temperature is generally performed. 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 earnest studies on a method for improving the catalytic activity, it was found that reducing the secondary particle size of mordenite in the molded catalyst improves the catalytic activity of the DCT isomerization reaction, and arrived at the present invention. did.

[0008]

The present invention provides a DCT catalyst composition in which the secondary particle size of mordenite in a catalyst molded body is at most 5 microns or less, and a DCT isomerization method using the catalyst. is there. Prior to use in the DCT isomerization reaction, the catalyst composition containing mordenite,
Must be in 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 introduce silver ions into mordenite. The silver ion may be reduced during the reaction or may be in the form of other compound, but it does not cause any problem in the catalytic performance. Furthermore, it is preferable to add a fluorine and / or phosphorus component. Further, when used in the reaction, it is preferable that the feedstock DCT is brought into contact with the catalyst in a liquid phase. Coexistence of hydrogen as a feedstock is preferable for suppressing a decrease in catalyst activity. By dissolving hydrogen in the DCT liquid phase, the effect can be more exerted. To dissolve effective amount of hydrogen in DCT, the reaction pressure is 4M.
It is necessary to make Pa or more. The details will be described below.

[0009]

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

[0010]

[Table 1]

Mordenite includes natural products and synthetic products.
Synthetic products are preferred for the present invention. Various methods have been disclosed so far as methods for synthesizing mordenite. For example, Japanese Examined Patent Publication No. 47-46677 and Japanese Patent Laid-Open No. 55-126529.
JP-A-58-91032 and the like. 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 will decrease. Silica / alumina molar ratio is 1
In order to obtain mordenite of 5 to 30, a method of dealumination treatment of mordenite having a low silica / alumina molar ratio by acid extraction or the like and direct silica / alumina molar ratio of 15
There is a method of synthesizing mordenite of No. 30 to 30 but a directly synthesized synthetic mordenite is preferably used.

When the mordenite is in powder form,
Molding is necessary for industrial use as a catalyst. There are various molding methods such as compression molding method, kneading method, and oil drop method, and the kneading method is preferably used. As the kneading method, a binder is generally required, and an inorganic oxide and / or clay is used. Examples of binders preferably used in the present invention include alumina sol and alumina gel. The amount of binder is 5 per 100 parts by weight of mordenite on an absolute dry basis.
To 30 parts by weight, preferably 10 to 20 parts by weight. When moldability is poor, sodium chloride during kneading,
Alkali metal salts such as magnesium chloride and barium chloride,
It is effective to add an alkaline earth metal salt or to add a surfactant such as polyvinyl alcohol, span, or rheodol. The particle size of the molded body is extremely important because it greatly affects the diffusion rate during the DCT isomerization reaction. When the particle size is small, the diffusion rate is high, which is preferable, but since the pressure loss is large, an appropriate particle size is preferable. In the present invention, the particle size is 0.05 to 2 mm, more preferably 0.1 to 1 m.
m. The compact is then dried at 50 to 200 ° C and then fired at 350 to 600 ° C to increase the compact strength.

The secondary particles of mordenite are aggregates of primary crystallites of mordenite, and the secondary particle size of mordenite in the molded catalyst is determined by scanning electron microscope (SE).
It can be easily examined with M). For the purposes of the present invention,
It is effective that the secondary particle size of mordenite in the molded catalyst is 5 μm or less at maximum. At least 10 SEM photographs of a catalyst molded body were taken, and if there are no secondary particles of 5 μm or more within the range of 100 μm × 100 μm, the particles contained in the catalyst molded body are sufficiently dispersed. ,
It is judged that there are no secondary particles of 5 μm or more. When the raw material mordenite is uniformly mixed with the inorganic oxide and / or clay and molded, some of the secondary particles collapse and disperse, but the secondary particles of mordenite in the catalyst molded body are sufficiently small and highly The more dispersed the catalyst, the more effective the catalyst is, and the more the effect of rhenium is exhibited, the more the catalytic activity of the DCT isomerization reaction is improved. The secondary particle size of mordenite in the catalyst molded body is controlled by the molding conditions and the secondary particle size of the raw mordenite powder. As molding conditions, time and water content at the time of kneading mordenite with an inorganic oxide and / or clay are important. For example, the longer the kneading time, the smaller the secondary particle diameter of mordenite in the catalyst molded body, which is preferable. Further, the secondary particle size of the raw material mordenite powder can be controlled by the reaction mixture composition ratio during mordenite synthesis, the crystallization time, the stirring conditions and the drying method, etc. You have to choose. According to the findings so far,
When the alkalinity in the reaction mixture during mordenite synthesis is lowered or the crystallization time is shortened, the secondary particle size tends to be small.

It is preferable that the mordenite contained in such a molded body is in an acid form. In the case of the acid form or the form of hydrogen ion precursor ammonium ion or organic cation before molding, it is not always necessary to perform a new treatment to form the acid form, but alkali metal ions, alkaline earth metal ions, etc. When it contains, an ion exchange treatment is carried out to convert it into an acid form. Ion exchange treatment is a case of directly converting to an acid form with an aqueous solution of inorganic acid, organic acid,
There is a method in which ion exchange is performed with an aqueous solution of ammonium chloride, ammonium nitrate or the like to introduce ammonium ions, and then baking is performed to convert the ions into hydrogen ions to form an acid form. It is preferable to carry out ion exchange with an ammonium salt aqueous solution, since dealumination of mordenite easily occurs when the ion exchange is carried out with an acid aqueous solution.

The introduction of silver ions into mordenite can be easily achieved by ion exchange of the mordenite molding with an aqueous solution of silver nitrate. 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 side reactions in the DCT isomerization reaction. The silver ion introduced into mordenite may become a metal or other compound such as chloride during the reaction, but it does not deteriorate the catalytic performance.

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

At least one of fluorine and phosphorus is introduced by an impregnation method, a mixing method or the like. What can be used as the fluorine component is preferably a water-soluble fluorine compound, and examples thereof include ammonium fluoride. The water-soluble phosphorus compound is preferably used as the phosphorus component, and examples thereof include phosphoric acid, ammonium phosphate, and ammonium hydrogenphosphate. The fluorine and / or phosphorus component is preferably contained in the catalyst composition in an amount of 0.05 to 2% by weight as a fluorine atom and / or a phosphorus atom.

The catalyst composition thus prepared was 5
Dried at 0 to 200 ° C, then 350 to 600 ° C
It is then calcined and subjected to a DCT isomerization reaction.

As the isomerization reaction system of DCT, any of a fixed bed, a moving bed and a fluidized bed can be used, but a fixed bed flow reaction system is particularly preferable from the viewpoint of easy operation. Reaction temperature is 2
The temperature is 50 to 500 ° C, preferably 250 to 350 ° C.

The DCT isomerization reaction is preferably brought into contact with the catalyst in the liquid phase in the presence of hydrogen. By reacting in the liquid phase, the high boiling point compound generated by the reaction flows out of the system together with the reaction product, so that the catalytic active site is not covered and deterioration of the catalyst over time is suppressed. It is considered that hydrogen can remove the high boiling point compound covering the catalytically active sites by hydrogenolysis, and as a result, suppresses the deterioration of the catalytic activity. The amount of hydrogen is 0.00 in terms of molar ratio with respect to DCT.
5 to 0.2, preferably 0.02 to 0.1. In this case, it is particularly preferable to dissolve hydrogen in DCT in order to exert its effect. The catalyst activity can be prevented from deteriorating by setting the reaction pressure to preferably 4 MPa or more in order to dissolve hydrogen in the liquid phase DCT.

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

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

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

[0024]

EXAMPLES The present invention will be described below with reference to examples. Example 1 Solid caustic soda (NaOH content 96.0 wt%, H ₂ O
Content 4.0 wt%, Katayama Chemical Co., Ltd. 1.53 g, sodium aluminate solution (Al ₂ O ₃ content 18.5 wt%, NaO
H content 26.1 wt%, H ₂ O 55.4 wt%, Sumitomo Chemical 25.0 g, tetraethylammonium hydroxide (hereinafter referred to as “TEAOH”) (TEAO
H content 20wt%, H ₂ O content 80wt%, Sanyo Kasei)
66.6 grams was added to 575 grams of distilled water to make a homogeneous solution. Hydrous silicic acid (SiO2 content 9
1.6wt%, Al ₂ O ₃ content 0.33wt%, NaOH
78.7 g of a content of 0.27 wt%, Nipseal VN-3, Nippon Silica) was 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 0.246 TEA / SiO ₂ 0.075 H ₂ O / SiO ₂ 30 The reaction mixture was placed in a 1000 ml autoclave and sealed, then at 250 rpm. The mixture was reacted at 160 ° C. for 7 days while stirring.

After completion of the reaction, washing with distilled water 5 times and filtration were repeated, followed by drying at about 120 ° C. overnight. The product obtained was mordenite having the X-ray diffraction pattern shown in Table 1. The silica / alumina molar ratio of this mordenite was 21.5 as a result of compositional analysis. Example 2 Alumina powder having a boehmite structure (α-alumina monohydrate) in 30 g of mordenite powder obtained in Example 1 (absolute dry basis) (Al ₂ O ₃ content 75.0 wt%,
SCF type, Condea Corporation 4 g, alumina sol (Al ₂ O ₃ content 10 wt%, colloidal alumina 20)
0, Nissan Chemical Co., Ltd., 15 g, alumina gel (Al ₂ O ₃ content 70 wt%, Cataloid AP (C-10), catalyst formation) 4.3 g were added and kneaded for about 2 hours. During kneading, an appropriate amount of distilled water was added while checking the kneading state to form a paste-like mixture. This was made into a noodle-shaped molded body through a screen having a hole of 0.3 mmφ. 12
After drying at 0 ° C. overnight, it was baked at 500 ° C. for 2 hours.

Take 30 g of the fired compact and set it to 10 w
80-85 ° C with t% ammonium chloride aqueous solution
Ion exchange treatment was performed for 1 hour. After repeating this ion exchange treatment 5 times, it was washed 5 times with distilled water. It was dried overnight at 120 ° C. to obtain an ammonium ion exchange type molded body.

Half of the obtained ammonium ion-exchange type molded product was taken and a 1N aqueous solution of ammonium fluoride 45 was used.
Soaked in gram for 3 hours at room temperature. Then, the solution was drained and immersed in 30 g of an aqueous solution containing 75 mg of perrhenic acid in terms of rhenium metal at room temperature for 3 hours. Then, the liquid was drained, dried overnight at 120 ° C., baked at 500 ° C. for 1 hour and then baked at 540 ° C. for 3 hours to convert ammonium ions into hydrogen ions, thereby obtaining a catalyst composition A containing acid type mordenite. Obtained. The rhenium contained in the catalyst composition A is 0.
It was 3 wt% and fluorine was 0.9 wt%. Also, SE
According to M observation, the maximum secondary particle diameter of mordenite in the catalyst molded body was 3 μm. An example of the observed SEM image is shown in FIG. Example 3 The other half of the ammonium ion exchange-molded article obtained in Example 2 was 30 g of an aqueous solution containing 0.45 g of silver nitrate in terms of silver metal at room temperature for 30 minutes, followed by 1 at 70 ° C.
A silver ion exchange treatment was carried out for an hour. After washing with distilled water 5 times, 1
Dry overnight at 20 ° C. Then, it was immersed in 45 g of a 1 N aqueous solution of ammonium fluoride at room temperature for 3 hours. After that, the liquid is drained, and perrhenic acid is converted to rhenium metal at 75
It was immersed in 30 g of an aqueous solution containing milligrams at room temperature for 3 hours. After that, the liquid is drained and dried at 120 ° C. overnight, then 500
The resulting mixture was calcined at 540 ° C. for 1 hour and then at 540 ° C. for 3 hours to convert ammonium ions into hydrogen ions to obtain a catalyst composition B containing acid type mordenite. The catalyst composition B contained 2.8 wt% silver, 0.3 wt% rhenium, and 0.9 wt% fluorine. Also, by SEM observation,
The maximum secondary particle diameter of mordenite in the catalyst molded body was 3 microns. Comparative Example 1 A catalyst composition C was prepared in the same manner as the catalyst composition B except that the kneading time during the catalyst molding was about 30 minutes. According to SEM observation, the maximum secondary particle size of mordenite in the catalyst molded body was 10 μm. An example of the observed SEM image is shown in FIG. Example 4 For catalyst compositions A, B and C in which the secondary particle size of mordenite in the catalyst molded body was changed by the above method, DC
The results of the T isomerization reaction test are shown in Table 2.

[0029]

[Table 2]

It can be seen from Table 2 that the reaction temperature can be lowered because the catalytic activity is high when the maximum secondary particle diameter of mordenite in the catalyst molded body is smaller than 5 microns. Comparative Example 2 Sodium aluminate solution (Al ₂ O ₃ content 18.5 wt%,
NaOH content 26.1 wt%, H ₂ O 55.4 wt%,
Sumitomo Chemical) 42.6 g, TEAOH (TEAOH content 20 wt%, H ₂ O content 80 wt%, Sanyo Kasei) 6
9.9 grams was added to 562 grams of distilled water to make a homogeneous solution. Hydrous silicic acid (SiO2 content 91.
6wt%, Al ₂ O ₃ content 0.33 wt%, NaOH content of 0.27 wt%, Nipseal VN-3, Japan Silica)
78.7 grams were slowly added with stirring to prepare a homogeneous aqueous slurry reaction mixture. The composition ratio (molar ratio) of this reaction mixture was as follows.

SiO ₂ / Al ₂ O ₃ 15 OH ⁻¹ / SiO ₂ 0.315 TEA / SiO ₂ 0.079 H ₂ O / SiO ₂ 30 The reaction mixture was placed in a 1000 ml autoclave and sealed, and then at 250 rpm. The mixture was reacted at 160 ° C. for 7 days while stirring.

After completion of the reaction, washing with distilled water 5 times and filtration were repeated, and the product was dried at about 120 ° C. overnight. The product obtained was mordenite having the X-ray diffraction pattern shown in Table 1. The silica / alumina molar ratio of this mordenite was 13.1 as a result of compositional analysis.

The obtained mordenite powder was used as a catalyst composition B.
A catalyst composition D was prepared in the same manner as above. According to SEM observation, the maximum secondary particle size of mordenite in the catalyst molded body was 4 μm. Table 2 shows the results of the same reaction as in Example 4 performed on the catalyst composition D. From Table 2 the silica / alumina molar ratio of mordenite is 15 to 30.
It turns out that is excellent.

[0034]

According to the present invention, the catalytic activity of the DCT isomerization reaction is improved and the reaction temperature can be lowered.

[Brief description of drawings]

FIG. 1 S of the particle structure of catalyst composition A prepared in the example
It is a figure showing an EM image.

FIG. 2 S of the particle structure of the catalyst composition C prepared in the example
It is a figure showing an EM image.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields investigated (Int.Cl. ⁷ , DB name) B01J 21/00-37/36 C07C 17/358 C07C 25/02 JISST file (JOIS) WPI (DIALOG)

Claims (15)

(57) [Claims] 1. A isomerization catalyst composition for dichlorotoluene, characterized in that the secondary particle size of mordenite in the molded catalyst is 5 μm or less at maximum. 2. The dichlorotoluene isomerization 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 isomerization catalyst composition of dichlorotoluene according to 2. 4. The isomerization catalyst composition of dichlorotoluene according to claim 3, which contains rhenium and silver. 5. The dichlorotoluene isomerization catalyst composition according to claim 3, wherein rhenium is contained in an amount of 0.05 to 2% by weight in terms of metal based on the catalyst composition. 6. Rhenium is contained in the catalyst composition in an amount of 0.05 to 2% by weight in terms of metal, and silver is contained in the catalyst composition in an amount of 0.5 to 10% by weight in terms of metal. Item 5. A dichlorotoluene isomerization catalyst composition according to Item 5. 7. The catalyst composition according to claim 6, wherein rhenium is contained in an amount of 0.05 to 1% by weight in terms of metal, and silver is contained in the catalyst composition in an amount of 1 to 7% by weight in terms of metal.
A dichlorotoluene isomerization catalyst composition as described. 8. The isomerization catalyst composition for dichlorotoluene according to claim 3, which contains at least one component of fluorine and phosphorus. 9. The isomerism of dichlorotoluene according to claim 8, wherein at least one of fluorine and phosphorus is contained in the catalyst composition in an amount of 0.05 to 2% by weight as a fluorine atom and / or a phosphorus atom. Catalyst composition. 10. A mordenite having a silica / alumina molar ratio of 15 to 30.
An isomerization catalyst composition of dichlorotoluene according to any one of 1. 11. A process for isomerizing dichlorotoluene, which comprises contacting dichlorotoluene with the isomerization catalyst composition for dichlorotoluene according to any one of claims 1 to 10. 12. The method for isomerizing dichlorotoluene according to claim 11, wherein dichlorotoluene is isomerized in the liquid phase in the presence of hydrogen. 13. The method for isomerizing dichlorotoluene according to claim 11 or 12, wherein the dichlorotoluene is isomerized at a reaction pressure of 4 MPa or more. 14. The method for isomerizing dichlorotoluene according to claim 11, wherein hydrogen is supplied in a molar ratio of 0.005 to 0.2 with respect to dichlorotoluene. 15. The method for isomerizing dichlorotoluene according to claim 14, wherein hydrogen is supplied in a molar ratio of 0.02 to 0.1 with respect to dichlorotoluene.