JP3509478B2 - 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- and / or 3,5-isomer from a mixture of 2,6- and / or 3,5-poor DCT isomers, which is poor in DCT 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 of causing such an isomerization reaction, Japanese Patent Publication No. 37054/1992 and Japanese Patent Publication No. 37/1992
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, the inventors have found that reducing the crystallite of mordenite improves the catalytic activity of the DCT isomerization reaction, and arrived at the present invention.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a catalyst composition containing mordenite having a crystallite long axis of 0.2 μm or less, and a DCT isomerization method using the catalyst.

The catalyst composition containing mordenite is DC
The acid form is preferred prior to use in the T isomerization reaction. 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. 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. The reaction pressure is preferably set to 4 MPa or more in order to dissolve hydrogen in the effective amount of DCT. The details will be described 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 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, JP-B-47-46677 and JP-A-55-126529.
JP-A-58-91032 and the like. The size of the crystallite of mordenite changes variously depending on the composition of the reaction mixture at the time of synthesis, crystallization temperature, crystallization time, stirring speed, etc., so it cannot be said unequivocally, but the general tendency is that tetraethylammonium is present in the reaction mixture. The presence of organic base nitrogen compounds such as hydroxide and surfactants such as polyethylene glycol tends to reduce the crystallites. Regarding the composition ratio in the reaction mixture, the crystallite size changes intricately 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 the crystallization conditions, if the crystallization temperature is lowered, the crystallization time is shortened, or the stirring speed is increased, the crystallites tend to be small. Whichever method is used, it is sufficient for the present invention that the major axis of the crystallite of mordenite is 0.2 micron or less.

The crystallite size of mordenite can be easily examined by 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 will decrease.

When the mordenite is in powder form,
Molding is preferred for industrial use as a catalyst. 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 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 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 an absolute dry basis. When moldability is poor, add sodium chloride, magnesium chloride, barium chloride or other alkali metal salt or alkaline earth metal salt when kneading, or use polyvinyl alcohol,
It is effective to add a surfactant such as span or rheodol.

The particle size of the molded article 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, preferably 0.1 to 1 mm
Is. The compact is then dried at 50 to 200 ° C. and then fired at 350 to 600 ° C. to increase compact strength.

It is preferable that the mordenite contained in such a molded body is in the acid form. In the case of the form of an acid form or ammonium ion which is a hydrogen ion precursor or an organic cation before molding, it is not always necessary to perform a new treatment to form an 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 compact 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.

The catalyst composition thus prepared has 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 a 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 catalytic active site by hydrogenolysis, and as a result, suppresses the deterioration of 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. In order to dissolve hydrogen in liquid phase DCT, the reaction pressure is preferably set to 4 MPa or more to prevent deterioration of catalyst activity.

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

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

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

[0025]

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

Example 1 Solid caustic soda (NaOH content 96.0 wt%, H ₂ O
Content 4.0 wt%, Katayama Chemical Co., Ltd. 0.40 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 23.89 g, tetraethylammonium hydroxide (hereinafter referred to as “TEAOH”) (TEA
55.2 g of OH content 20 wt%, H ₂ O content 80 wt%, Sanyo Kasei) was added to 567 g of distilled water to form a uniform solution. Hydrous silicic acid (SiO2 content 91.6 wt%, Al ₂ O ₃ content 0.33 wt%, NaO
65.5 g of H content of 0.27 wt%, Nipseal VN-3, Nippon Silica) were gradually added with stirring to prepare a uniform aqueous slurry 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 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, 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 18.5 as a result of composition analysis. As a result of observing the crystallite of mordenite by SEM, the major axis of the crystallite was 0.12 micron.

Example 2 Alumina sol (Al ₂ O ₃ content 10 wt%, colloidal alumina 200, Nissan Kagaku) 2 as a binder was added to 30 g of mordenite powder obtained in Example 1 (absolute dry basis).
4 g, alumina gel (Al ₂ O ₃ content 70 wt%, C
3 g of ataloid AP (C-10), catalytic conversion) was added and kneaded. 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. After drying overnight at 120 ° C, 550
Calcination was carried out for 2 hours.

25 g of the fired compact is taken and 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 body was taken, and perrhenic acid was converted to 6 in terms of rhenium metal.
It was immersed for 6 hours at room temperature in 25 grams of an aqueous solution containing 2.5 milligrams. Then, the liquid was drained, dried overnight at 120 ° C., and subsequently calcined at 515 ° C. for 4 hours to convert ammonium ions into hydrogen ions to obtain a catalyst composition A containing acid mordenite. The rhenium contained in the catalyst composition A was 0.3 wt%.

On the other hand, the other half of the ammonium ion exchange type 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. After that, perrhenic acid was immersed in 25 g of an aqueous solution containing 62.5 mg of rhenium metal at room temperature for 6 hours. After that, the liquid is drained, dried at 120 ° C. overnight, and then 5
Catalyst composition B containing ammonium mordenite that is converted to hydrogen ions by calcination at 15 ° C. for 4 hours.
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 Co., Ltd. 1.22 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 Co., Ltd. 20.88 g, tetraethylammonium hydroxide (hereinafter referred to as “TEAOH”) (TEA
55.2 g of OH content 20 wt%, H ₂ O content 80 wt%, Sanyo Kasei) was added to 479 g of distilled water to form a uniform solution. Hydrous silicic acid (SiO2 content 91.6 wt%, Al ₂ O ₃ content 0.33 wt%, NaO
65.5 g of H content of 0.27 wt%, Nipseal VN-3, Nippon Silica) were gradually added with stirring to prepare a uniform aqueous slurry 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 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, 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 21.3. As a result of observing the crystallite of mordenite by SEM, the major axis of the crystallite was 0.16 micron.

Example 4 The mordenite powder obtained in Example 3 was prepared in the same manner as the catalyst composition A of Example 2 to obtain a catalyst composition C.
Further, 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
Content 4.0 wt%, Katayama Chemical Co., Ltd. 21.3 g, tartaric acid powder (tartaric acid content 99.7 wt%, H ₂ O content 0.3 w
t1.3%, Katayama Chemical) 21.3 g was dissolved in 587 g of distilled water. Sodium aluminate solution (Al ₂
O ₃ content 18.5 wt%, NaOH content 26.1 wt
%, H ₂ O 55.4 wt%, Sumitomo Chemical Co., Ltd. 29.2 g to make a uniform solution. Hydrous silicic acid (SiO2 content 91.6 wt%, Al ₂ O ₃ content 0.33
wt%, NaOH content 0.27 wt%, Nipseal V
(N-3, NIPPON SILICA) 111.5 grams was gradually added with stirring to prepare a uniform aqueous slurry 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: The tartrate reaction mixture was placed in an autoclave of 1000 ml volume. After sealing, the mixture was reacted at 160 ° C. for 3 days while stirring at 250 rpm.

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 18.6 as a result of composition analysis. As a result of observing the crystallite of mordenite by SEM, the major axis of the crystallite was 0.36 micron.

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

Example 5 Table 2 shows the results of a DCT isomerization reaction test conducted on catalyst compositions A to E.

[0042]

[Table 2]

[0043]

From Table 2, it can be seen that when the major axis of the crystallite of mordenite is smaller than 0.2 micron, the reaction temperature can be lowered because the catalytic activity is high.

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

Claims (13)

(57) [Claims] 1. A dichlorotoluene isomerization catalyst composition comprising mordenite having a crystallite long axis of 0.2 micron or less. 2. The catalyst composition according to claim 1, wherein the mordenite is in the 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, which contains 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 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. The 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.
The described catalyst composition. 8. The mordenite having 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, which comprises contacting dichlorotoluene with the catalyst composition according to any one of claims 1 to 8. 10. The method for isomerizing dichlorotoluene according to claim 9, wherein dichlorotoluene is isomerized in a liquid phase in the presence of hydrogen. 11. The dichlorotoluene is isomerized at a reaction pressure of 4 MPa or more, and the dichlorotoluene is isomerized.
0 method for dichlorotoluene isomerization 12. The method 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 to dichlorotoluene.