JPS6215050B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for catalytic isomerization of halogenated toluene. In the present invention, halogenated toluene refers to toluene substituted with a nuclear monohalogen, including o-halogenated toluene, m-halogenated toluene, and p-halogenated toluene.
- means each isomer of halogenated toluene. Generally, halogenated toluene is obtained by subjecting toluene to a nuclear substitution reaction with a halogen. And this halogenation reaction is op-
This is a highly oriented reaction, and if the m-isomer is required, isomerization must be used. Furthermore, the ratio of the demand for each isomer of halogenated toluene is often different from the production ratio of each isomer during halogenation. Therefore, the isomerization method has important technical significance in order to effectively utilize halogenated toluene. Conventional examples of such isomerization reactions include:
Olah, GA, J.org.Chem.27, 3464 (1964), a method using aluminum chloride as a catalyst, and a method using HF-BF ₃ as a catalyst, disclosed in Japanese Patent Publication No. 11809/1980, are known. It is being However, these conventionally known isomerization reactions do not have sufficient catalytic activity, require a long reaction time, or require a large amount of catalyst, and are also prone to corrosion of the reaction equipment and reaction products and catalyst components. None of these methods are preferable as industrial isomerization methods, as they involve problems such as difficulty in separation. The present inventors investigated in order to overcome these drawbacks of the conventional method and establish an industrially superior method for isomerizing halogenated toluene, and as a result, they first discovered that an acid type zeolite catalyst was highly effective. The present inventors continued to conduct intensive studies to develop a catalyst with high halogenated toluene isomerization activity and high selectivity. It was discovered that a compound having a significantly high activity and selectivity for this reaction led to the present invention. That is, the present invention provides a method for catalytic isomerization of halogenated toluene, which comprises using as a catalyst an acid form of zeolite whose main cavity has a 10-membered oxygen ring at the entrance. It is. The zeolite used in the catalytic isomerization method of halogenated toluene of the present invention has an entrance of the main cavity.
This zeolite is known as ZSM-5 type zeolite, and its composition and manufacturing method are described in U.S. Pat. No. 3,894,106, and in Nature 271 , 30 March, 437.
(1978), whose crystal structure is described in ZSM−
5 zeolite and zeolites considered to belong to the same series, specifically, for example, in addition to the above-mentioned ZSM-5, ZSM-8 described in British Patent No. 1334243, Japanese Patent Publication No. 53-7
ZSM-11 described in US Patent No. 23280, ZSM-11 described in US Patent No. 4001346
21, described in the specification of JP-A-53-144500
ZSM-35, zeolite zeta 1 described in JP-A-51-67299 and JP-A-51-
Zeolite Zeta 3 described in the specification of No. 67298 is exemplified. Of course, any zeolite having a structural characteristic in which the entrance of the main cavity has a 10-membered oxygen ring can be used without being limited to the above-mentioned examples. ZSM, a typical catalyst component in the present invention
-5 is a zeolite having the following composition expressed in molar ratio of oxides: 0.9±0.2M〓O:Al ₂ O ₃ :
_5-100SiO2 : _0-40H2O (where M is a cation and n is the valence of the cation) and has a 10-membered oxygen ring. To synthesize ZSM-5, a solution containing tetrapropylammonium hydroxide, sodium oxide, aluminum oxide, silicon oxide, and water is prepared, and its composition expressed in molar ratio is within the following range, and OH ^- / _SiO2 0.07 _~ 1.0 R4N ⁺ /( _R4N ⁺⁺ Na ⁺ ) 0.2~0.95 _H2O /OH ^- 10~300 _SiO2 / _{Al2O3 5} ~100 (R is a propyl group) This is preferably carried out by heating at a temperature of about 90 to 200°C for about 6 hours to 60 days. Also, Tokukai Akira
No. 54-60297 discloses a method for the synthesis of ZSM-5 using primary amines having 2 to 10 carbon atoms as organic nitrogen-containing cation precursors. The zeolite used in the isomerization reaction of the present invention is used in an acid form. As is well known, acid-type zeolites have polyvalent cations of divalent or higher valence, such as protons, ammonium cations, or rare earth ions, as cations in the zeolite. These are usually obtained by ion-exchanging at least a part of the alkali metal ions of a zeolite containing monovalent alkali metal ions such as sodium with protons, ammonium cations, or polyvalent cations, but the zeolites are usually organic nitrogen-containing cations. Since the organic nitrogen-containing cations are decomposed and converted into protons by calcination, an acid type zeolite can be obtained. Of course, if necessary, the alkali metal ions such as sodium present in the zeolite during the zeolite production may be further ion-exchanged with protons or ammonium cations by a known ion exchange method, or a polyvalent cation of divalent or higher valence may be introduced. It is also possible. In any case, in the method of the present invention, the zeolite need only be acidic, and the type and amount of cations are not limited at all. In the isomerization method of the present invention, the zeolite is usually used as a molded body. The molding method is not particularly limited, and known methods such as a rolling method, an extrusion method, and a compression method can be applied. Furthermore, it is also possible to add a binder such as alumina sol or clay if necessary during molding. Note that the ion exchange treatment can be performed at any stage before or after molding the zeolite. In the isomerization method of the present invention, the acid type ZSM-5 type zeolite molded body prepared as described above is activated as a catalyst by firing it usually at 300 to 600°C, and this catalyst is used to perform halogenation. It catalytically isomerizes toluene. Although such a reaction can be carried out according to various conventionally known isomerization operations, a fixed bed flow reaction is particularly preferred because of its ease of operation. The reaction temperature is usually about 200 to 500℃, but especially 250 to 500℃.
400°C is preferred. The isomerization reaction of the present invention aims to extend the life of the catalyst and reduce side reactions.
Favorable results can be obtained when the isomerization reaction is carried out in the presence of an aromatic hydrocarbon or a halogenated benzene corresponding to the halogenated toluene. The halogenated toluene to be isomerized in the present invention is at least one of o-halogenated toluene, m-halogenated toluene, and p-halogenated toluene, and the halogen is chlorine. , bromine, iodine and fluorine are used. The present invention will be explained in detail below using examples. Example 1 An acid type ZSM-5 catalyst was prepared by the preparation method shown below. First, zeolite ZSM-5 was synthesized according to US Pat. No. 3,894,106. White carbon (SiO ₂ 88.1wt%, H ₂ O 11.9wt
%) was added to 100 ml of 2.31N tetrapropylammonium hydroxide (C ₃ H ₇ ) ₄ NOH and heated at about 100°C. After that, a sodium aluminate aqueous solution (Al ₂ O ₃ 19.5 wt%, Na ₂ O 20.2 wt%,
A solution of 3.53 g of H ₂ O (60.3 wt%) mixed with 53 ml of water was added and stirred sufficiently to form a homogeneous mixture. The composition ratio (molar ratio) of the mixture was as follows. [(C ₃ H ₇ ) ₄ N] ₂ O 17.1 Na ₂ O 1.7 SiO ₂ 56.5 Al ₂ O ₃ 1.0 H ₂ O 937 The above reaction mixture was placed in an autoclave and crystallized at 150°C for 120 hours with stirring. . After crystallization, wash with distilled water until neutral and heat at 120°C.
and dried for 15 hours. The product was examined by X-ray diffraction and was confirmed to be zeolite ZSM-5. To the thus obtained ZSM-5 powder, 15 wt % of alumina sol was added in terms of Al ₂ O ₃ , and after kneading, the mixture was extruded into 14 to 24 meshes and fired in air at 500° C. for 3 hours. This ZSM-5 molded body was mixed with a 10wt% ammonium nitrate aqueous solution (solid-liquid ratio 2.0/Kg,
Perform ion exchange 4 times (at approximately 90℃) and rinse thoroughly with water.
After drying at 120°C for 15 hours, it was calcined in air at 500°C for 1 hour to obtain an acid type ZSM-5 catalyst. Example 2 Using the acid type ZSM-5 catalyst obtained in Example 1, an isomerization reaction of orthochlorotoluene (o-CT) was carried out. The reaction conditions are shown below. Feed composition o-CT/CB=1/4wt/wt N ₂ /feed 5/1mol/mol Feed amount 12.8g/hr Catalyst amount 4.0g Reaction temperature 320℃ Reaction pressure 20Kg/cm ² The composition of CT after reaction is o -CT49.0%, m-
CT was 37.4%, p-CT was 13.6%, the amount of B+T produced as a side reaction product was 0.3 wt%, and the amount of DCB+CX produced was ~0. However, the abbreviations mean the following. CB: Chlorobenzene B: Benzene T: Toluene DCB: Dichlorobenzene CX: Chlorxylene m-CT: Methachlorotoluene p-CT: Parachlorotoluene Example 3 Acid type ZSM-5 catalyst obtained in Example 1 The isomerization reaction of o-CT was carried out using the following reaction conditions. Feed composition o-CT N ₂ /feed 5/1mol/mol Feed amount 12.8g/hr Catalyst amount 4.0g Reaction temperature 320℃ Reaction pressure 20Kg/cm ² The composition of CT after reaction is o-CT78.9%, m-
CT16.5%, p-CT4.6%, and the amount of B+T+CB produced as a side reaction product is 0.8wt%, DCB+CX
The amount produced was ~0. Comparative example 1 10wt% sodium type synthetic mordenite powder
Using ammonium nitrate aqueous solution (solid-liquid ratio 2.0
/Kg at 90°C) 5 times, washed thoroughly with water, and dried at 120°C for 15 hours. Add alumina sol to this mordenite powder at 15wt% in terms of Al ₂ O ₃
After addition and kneading, extrusion molding was performed to obtain a molded body of 14 to 24 meshes, which was calcined in air at 500°C for 1 hour to obtain an acid type mordenite catalyst. Using the acid type mordenite catalyst thus obtained, o-CT isomerization reaction was carried out under the following reaction conditions. Feed composition o-CT/CB=1/4wt/wt N ₂ /feed 5/1mol/mol Feed amount 12.8g/hr Catalyst amount 4.20g Reaction temperature 320℃ Reaction pressure 20Kg/cm ^2Reaction results are shown in Table 1 . Compared to Example 2, the acid type mordenite catalyst has a lower CT isomerization activity and more side reaction products than the acid type ZSM-5 catalyst.
In order to obtain the same o-CT isomerization rate with acid type mordenite catalyst as with acid type ZSM-5 catalyst, 5
More than double the amount of catalyst is required.

[Table] Example 4 Three different SiO ₂ /Al ₂ O ₃ ratios by the preparation method shown below
A seed acid form of ZSM-5 catalyst was prepared. First, zeolite ZSM with different SiO ₂ /Al ₂ O ₃ ratios
-5 was synthesized according to JP-A-50-54598.
Synthesis conditions are shown in Table 2. In Table 2, solution A is sodium silicate No. 3 (SiO ₂ 29.9wt%, Na ₂ O 8.9wt%).
%, water 62.2wt%) and water. Solution B is a solution consisting of Al ₂ (SO ₄ ) ₃ ·18H ₂ O, H ₂ SO ₄ and water. Solution C, n-propylamine, was added to solution A, followed by solution B and stirred until a homogeneous mixture. This reaction mixture was charged into an autoclave and crystallized while stirring.
After crystallization, wash with water until it becomes neutral, then
It was dried at 120°C for 15 hours. As a result of X-ray diffraction, all of the obtained zeolites were found to be ZSM-5. The three types of ZSM-5 powders D, E, and F with different SiO ₂ /Al ₂ O ₃ ratios thus obtained were molded and calcined in the same manner as in Example 1, and ion-exchanged with ammonium cations and calcined to obtain acid-type powders. Catalysts G, H and I were used.

【table】

[Table] Example 5 Three different SiO ₂ /Al ₂ O ₃ ratios obtained in Example 4
O-
The isomerization reaction of CT was carried out. The reaction conditions and reaction results are shown in Table 3.

[Table] Example 6 An acid type zeolite Zeta 3 catalyst was prepared by the preparation method shown below. First, zeolite Zeta 3 was synthesized according to the specification of JP-A-52-43800. Sodium silicate No. 3 (SiO ₂ 29.9wt%, Na ₂ O 8.9wt%, water 62.2wt%)
Solution A was prepared by dissolving 127.2 g in a mixed solution of 159.6 g of water and 25.1 g of isopropanol. Next 212.2g
of water and 7.7 g of aluminum sulfate Al ₂ (SO ₄ ) ₃ .
Solution B was made consisting of 18H ₂ O, 9.6 g of sulfuric acid.
Solution B was mixed into solution A with stirring to prepare a homogeneous slurry mixture. The composition ratio (molar ratio) of the reaction mixture was Na ₂ O 4.5 isopropanol 36.2 Na ₂ SO ₄ 11.3 Al ₂ O ₃ 1.0 SiO ₂ 53.0 H ₂ O 2185. Put this mixture into an autoclave,
Crystallization was carried out at 180° C. for 72 hours with stirring. The product was washed with distilled water until neutral and incubated at 120°C.
Dry for 15 hours. To the thus obtained zeolite zeta 3 powder was added 15 wt % of alumina sol in terms of Al ₂ O ₃ , and after kneading, the mixture was extruded into 14 to 24 meshes and calcined in air at 500° C. for 2 hours. This zeolite zeta 3
The molded body was ion-exchanged five times using a 10wt% ammonium nitrate aqueous solution (solid-liquid ratio 2.0/Kg, at about 90℃), thoroughly washed with water, and dried at 120℃ for 15 hours.
It was calcined in air at ℃ for 2 hours to obtain an acid type zeolite zeta 3 catalyst. Example 7 Using the acid type zeolite Zeta 3 catalyst obtained in Example 6, an isomerization reaction of o-CT was carried out in a liquid phase state. The reaction conditions are shown below. Feed composition o-CT/CB=1/1wt/wt Feed amount 20.0g/hr Catalyst amount 5.0g Reaction temperature 320℃ Reaction pressure 30Kg/cm ² The composition of CT after reaction is o-CT55.1%, m-
CT was 32.6%, p-CT was 12.3%, the amount of B+T produced as a side reaction product was 0.2 wt%, and the amount of DCB+CX produced was ~0.

Claims (1)

[Claims] 1. A method for catalytic isomerization of halogenated toluene, which is characterized in that an acid form of zeolite whose main cavity has a 10-membered oxygen ring at the entrance is used as a catalyst.