JPH02233623A - Production of ditolylmethane - Google Patents

Abstract

PURPOSE:To obtain the subject compound in high yield with excellent catalyst longevity without deteriorating activity by using a specific crystalline synthetic zeolite as a catalyst and reacting toluene with diphenylmethane and benzyltoluene or a mixture thereof under prescribed conditions. CONSTITUTION:Toluene is reacted with diphenylmethane, benzyltoluene or a mixture thereof at a molar ratio of the toluene to the diphenylmethane within the range of preferably 0.5-20 in the presence of a crystalline synthetic zeolite catalyst at >=2.0 molar ratio of SiO2/Al2O3 (either zeolite at an ultrahigh molar ratio of SiO2/Al2O3, e.g. >=1,600, or further zeolite, called silicalite substantially without containing aluminum, as necessary, may be used) having inlets of main cavities consisting of 10-membered oxygen rings at 170-400 deg.C, preferably 200-350 deg.C reaction temperature to afford the objective compound.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing ditolylmethane.

[Prior art and its challenges] Conventionally, the main method for producing ditolylmethane has been to react a halide such as methylbenzyl chloride with toluene. Furthermore, the patent application No. 62-5586 already filed by the present inventors
In specification No. 3, solid acids such as silica and alumina, Lewis acids such as aluminum chloride, etc. are used as disproportionation catalysts,
Ditolylmethane is produced from toluene and diphenylmethane.

As crystalline synthetic aluminosilicate/zeolite,
There are conventionally known zeolites such as mordenite and Y-type zeolite, but the present inventors have discovered that all of these conventional zeolites have a short catalyst life, that is, a significant decrease in activity, and that shape selection is difficult. It has also been found that these compounds have low properties and are not suitable for the method of the present invention.

Therefore, a method for producing ditolylmethane with good yield and selectivity is desired.

[Structure of the Invention] An object of the present invention is to produce ditolylmethane with good yield and selectivity.

That is, the present invention uses a crystalline synthetic zeolite catalyst in which the SiO2/At20, molar ratio is 20 or more and the entrance of the main cavity is composed of a 10-membered oxygen ring, and the reaction temperature is 1.
The present invention relates to a method for producing ditolylmethane, which comprises reacting toluene with diphenylmethane, benzyltoluene, or a mixture thereof at a temperature of 70 to 400°C.

The present invention will be explained in more detail below.

A typical example of a crystalline synthetic zeolite catalyst having a Sin2Hal20, molar ratio of 20 or more and whose main cavity has a 10-membered oxygen ring at the entrance is the ZSM-5 type catalyst, and when this catalyst is used, Compared to other conventionally used catalysts,
Ditolylmethane can be obtained with high yield and high selectivity.

Here, a method for producing xylene by disproportionation of toluene using ZSM-5 type zeolite as a catalyst has already been disclosed (Japanese Unexamined Patent Publication No. 50-96532, etc.). This is naturally due to the movement of methyl groups.

When ditolylmethane is produced from toluene and diphenylmethane using ZSM-5 type zeolite, if methyl group transfer occurs, 'because toluene is present,'
Naturally, it is expected that xylene will be produced. If xylene is produced, the raw material toluene is consumed accordingly, and the yield of ditolylmethane decreases, which is undesirable. Therefore, the ZSM-5 catalyst would not be expected to be suitable for producing ditolylmethane from toluene and diphenylmethane.

However, the present inventors surprisingly found that despite the presence of toluene, the reaction proceeded without substantially producing xylene, and ditolylmethane was produced.

The same applies to toluene and benzyltoluene.

The reaction conditions of toluene and diphenylmethane or benzyltoluene in the present invention are as follows.

First, the catalyst is a crystalline synthetic aluminosilicate zeolite having a SiOz/Alz03 molar ratio of 20 or more and having a 10-membered oxygen ring at the entrance of the main cavity. Examples of such olite include ZSM-5 type synthetic zeolite whose main cavity has a 10-membered oxygen ring at its entrance, as well as zeolite zeta 1, zeolite zeta 2, and the like. That is, the zeolite of the present invention is characterized by consisting of a 10-membered oxygen ring. Jumaru's synthetic zeolites, such as A-type zeolite, erionite, and offretite, are 8-membered oxygen ring type small-pore size zeolites.
Mordenite, X-type zeolite, Y-type zeolite, etc. are 12-membered oxygen ring type large-pore zeolites. These conventional zeolites consisting of 8-membered oxygen rings or 12-membered oxygen rings cannot be passed through the method of the present invention because their structure is different from that of the present invention.

The crystalline synthetic zeolite used in the present invention has a structural characteristic in which the main cavity entrance consists of a 10-membered oxygen ring, and Si
O. /Al, 0. Any crystalline synthetic aluminosilicate having a molar ratio of 20 or more can be used. Particularly preferred is a synthetic zeolite of type ZSM-5,
For example, ZSM-5, ZSM-11, ZSM-12, Z
SM-22, ZSM-23, ZSM-35, ZSM-3
8, ZSM-48, etc. These Z
All SM-5 type synthetic zeolites have a structural characteristic in which the main cavity entrance consists of a 10-membered oxygen ring. A particularly preferred synthetic zeolite is ZSM-5. These ZSM-
The composition and manufacturing method of type 5 zeolite are both described in the following patent publications.

ZSM-5: U.S. Patent No. 3,70 2,8
8 6 British Patent No. 1,161,974 and Japanese Patent Publication No. 1973-10064? SM-8: British Patent No. 1,334,243
No. ZSM-1 t: U.S. Patent No. 3,709
, 979 and Japanese Patent Publication No. 53-23280 2SM-21: U.S. Patent No. 4,001,3
4 No. 6 ZSM-35: JP-A-53-1445
No. 00 Zeolite Zeta 1: JP-A No. 51-67299 Zeolite Zeta 2: JP-A No. 51-67298 A synthetic zeolite with a structural characteristic in which the entrance of the main cavity consists of a 10-membered oxygen ring generally has a high SiOi/Al20s molar ratio. The value is usually 20 or more. In some cases, Si
O2/A1■03 molar ratio is very high, for example 1600
Zeolites such as those mentioned above are also effective. Furthermore, in some cases, substantially aluminum-free materials called silicalites, ie Si02/Al20. It is also possible to use zeolites with a molar ratio approaching infinity. Thus, "high silica" zeolites are also included within the definition of the present invention.

This Si02/Al,0 molar ratio is measured by a conventional analytical method such as atomic absorption spectrometry. This ratio represents as close as possible the ratio in the hard anionic framework of the zeolite crystals, excluding aluminum in cations or other forms in the binder or in the channels.

The structure in which the entrance of the main cavity consists of a 10-membered oxygen ring is usually x, I
Confirmed by I1 diffraction method. For example, ZSM-5 type synthetic zeolites, which are preferred as catalysts in the present invention, each have a unique characteristic X-ray diffraction pattern (see the above-mentioned patent publication for details).

However, even if this X-ray diffraction analysis method is not used, a measured value called a control index can be used instead of the X-ray diffraction method. That is, the 10-membered oxygen ring of the present invention can also be defined as a synthetic zeolite with a control index of 1 to 12. Here, a specific method for measuring the control index is shown in Japanese Unexamined Patent Publication No. 133223/1983. This index indicates the degree to which the pore structure of the zeolite crystal controls the access of molecules with a larger cross-sectional area than n-baraffin.

As disclosed in the publication, the measurement method involves adsorbing n-hexane and 3-methylbentane onto zeolite under certain conditions, and calculating from the amount of adsorption thereof. Typical control indices are as follows.

Control index ZSM-5 8.3 ZSM-11 8.7ZSM-35
4.5 Amorphous silica/alumina 0.6 To explain the method of synthesizing ZSM-5 as an example of the method for producing the zeolite of the present invention, first, tetraphammonium hydroxide, sodium oxide, aluminum oxide, silicon oxide, and water are used. Prepare a reaction raw material containing. The composition is within the range described in the above publication, and the reaction mixture is heated to perform hydrothermal synthesis. After synthesis, the obtained crystals are calcined in air to obtain a zeolite ZSM-5 catalyst. Tetrabubyl ammonium hydroxide can also be synthesized in situ from n-propylamine, probyl bromide, etc. in a reaction system. Although a method using aluminum oxide has been described here, it has also been proposed to synthesize ZSM-5 that does not substantially contain aluminum atoms.

In the above method, a method using tetrabropylammonium hydroxide was explained, but for example, as a method for synthesizing ZSM-5, it has been proposed to use various organic cations or existing compounds as their precursors instead. has been done. Examples include, for example, ammonia, trialkylmethylammonium cation, triethyl-n-propylammonium cation, C2-CI primary monoalkylamine, neopentylamine, di- or trialkylamine, alkanolamine, 05-C6 alkyl Diamines, 03-CI27 alkylene diamine, ethylene diamine, hexamethylene diamine, 03-C6 diol, ethylene or propylene glycol, pentaerythritol, diventaerythritol, tribetaerythritol, 1,4-dimethoxycyclohexane, hydroquinone, ethylene oxide and Ammonia, n-dodecylbenzenesulfonate, cyclopentadienylphthalocyanine complex, 2-aminopyridine, ethylene glycol? Examples include aliphatic carboxylic acids such as dimethyl ether, dioxane, dioxolane, tetrahydrofuran, and tartaric acid. In addition, it has even been proposed to produce the above-mentioned organic cations or organic compounds as their precursors without adding them, for example by adding ZSM-5 as a seed during crystallization. The zeolite used in the reaction contains, for example, sodium ions and other metal ions due to the reaction raw materials during synthesis. As the alkali metals and other metals with Na, alkaline earth metals such as calcium and magnesium, and also those obtained by ion exchange with only 3 metals can be used. Furthermore, crystalline synthetic aluminosilicate zeolites modified with boron, potassium, phosphorus, or compounds thereof, such as ZSM-5 type zeolites, can also be used. These ion exchanges or modifications can be performed by conventionally known methods.

As mentioned above, the crystalline synthetic zeolite of the present invention can contain various metals, but so-called hydrogen-type zeolites in which metal ions are exchanged with hydrogen ions are preferred for the method of the present invention. A typical hydrogen-type zeolite is prepared by inactivating a catalyst containing organic cations under an atmosphere of, for example, 4
Heating at 00 to 700°C for 1 hour, followed by ion exchange with ammonium salt or mineral acid such as hydrochloric acid, e.g.
The zeolite is activated by firing at 00 to 600°C, and a so-called hydrogen type zeolite is obtained.

The reaction temperature of the present invention is 170 to 400°C, preferably 20°C.
The temperature is 0 to 350°C.

If the reaction temperature is lower than this range, the conversion rate of the raw material will be low. On the other hand, if the reaction temperature is higher than this range, side reactions such as the production of xylene will occur, which is undesirable.

Although the reaction can be carried out in the gas phase, in order to maintain the catalytic activity for a long time, it is suitable to carry out the reaction in the liquid phase. Further, in the gas phase, it is necessary to raise the reaction temperature, and if the reaction temperature is high, side reactions such as the production of xylene are likely to occur as described above. The reaction is therefore carried out in the liquid phase.

In order to carry out the reaction in a liquid phase, the reaction pressure should preferably be set to an appropriate pressure to maintain the reaction phase in a liquid phase. This pressure is usually selected from the range of normal pressure to 50 kg/cm''. Either a flow type or a batch type can be selected as the reaction type for the method of the present invention. It is selected from the range of 0.5 to 50 hours depending on the temperature and other reaction conditions.If the reaction time is shorter than this range, the conversion rate will be low.Also, if the reaction time is longer than necessary,
This is not preferable because the yield of ditolylmethane is not improved, but rather only causes side reactions.

In the case of a flow reaction type, L} {SV is 0.2 to 20
,, preferably 0.5 to 10. If the LHSV is smaller than this, side reactions will increase and the yield per hour will decrease, which is not preferable. On the other hand, if LHSV becomes too large, the reaction will not proceed and the reaction raw materials will flow out of the system unreacted, which is not preferable.

In a batch process, the reaction/raw material mixture is usually 0.1
~10% by weight of catalyst may be used, preferably 0.5-5% by weight. If the catalyst concentration is lower than this, the reaction will not proceed, while if the catalyst concentration is higher than this, the yield of the target compound will not necessarily improve and the amount of catalyst used will be uneconomical, which is not preferable.

The molar ratio of toluene to diphenylmethane, benzyltoluene or a mixture thereof to be supplied to the reaction system is from 0.5 to 20, preferably from 1 to 10. If the molar ratio is smaller than this, that is, if the amount of toluene used relative to diphenylmethane is small, the raw material conversion rate will decrease, which is not preferable. Conversely, if the molar ratio is made higher than the above range and toluene is used in excess, reaction 1
This is not preferable because the amount of ditolylmethane produced per batch is reduced.

After the reaction is completed, unreacted toluene, diphenylmethane, benzyltoluene and benzene, which is a by-product of the disproportionation reaction of the present invention, are separated, and the ditolylmethane of the present invention is obtained by a conventional method.

[Effects of the Invention] The method of the present invention does not produce any heavier components as by-products, even when compared to the conventional method using an aluminum chloride catalyst. This is also true when compared with silica-alumina catalysts. Furthermore, there is virtually no xylene generation.

The present invention will be explained in detail with reference to Examples below.

[Example] Catalyst Preparation Example Aluminum sulfate, sulfuric acid, n-probylamine, and n-probyl bromide were dissolved in water, and water glass was gradually added to this solution while stirring to prepare a gel-like slurry as uniform as possible. did. This was placed in an autoclave and crystallized at 160° C. for 72 hours while stirring. After crystallization, the crystallization was filtered, and water washing and filtration were repeated until the washing liquid became neutral, thereby obtaining zeolite ZSM-5 having a Si02/Al2 molar ratio of 70. The obtained zeolite was calcined in air to prepare a catalyst. The X-ray diffraction diagram of this catalyst is disclosed in the above-mentioned patent publication (Japanese Patent Publication No. 46-10064).
No.). Furthermore, the control index and the like match, and therefore, the catalyst develops a structural characteristic in which the entrance of its main cavity is composed of a 10-membered oxygen ring.

Example 1 Zeolite ZSM-5 prepared in the above catalyst preparation example
200 ml of hydrogen form ZSM-5 (12 to 14 mesh) converted to hydrogen form by ion exchange with hydrochloric acid
was filled into a reaction vessel with an internal volume of 250 ml, and dried at 480°C for 3 hours while supplying dry nitrogen. Reaction temperature 290°C, pressure 20 atm (under nitrogen atmosphere), L
HSV=l. A mixed solution of 2 moles of toluene and 1 mole of diphenylmethane was passed through the flask at O.

The oil-passed reaction liquid was analyzed by gas chromatography to examine the composition of the reaction liquid after a certain oil-flow time.

The results are shown in Table 1. Example 2 4 moles of toluene, 2 moles of benzyltoluene, and H-ZSM-5 as a catalyst were placed in an autoclave with an internal volume of 21.
20g of was added and reacted at 270°C and 20 atm for 3 hours.

After the reaction, the reaction solution was analyzed, and ditolylmethane was produced with a conversion rate of benzyltoluene of 55% and a selectivity of ditolylmethane of 70%.

Comparative Example 1 A reaction vessel with an internal volume of 2,501 liters was filled with 200+ al of silica-alumina catalyst N-632L (trade name, manufactured by JGC ■, particle size: 12 to 14 mesh), which was a solid acid catalyst, and was heated to 250 ml while supplying dry nitrogen. It was dried at ℃ for 24 hours. Reaction temperature: 290°C, pressure: 20 atm (under nitrogen atmosphere). LHSV
= 1.0, a mixture of 2 moles of toluene and 1 mole of diphenylmethane was passed through the oil. As in Example 1, the reaction solution was analyzed by gas chromatography to examine the composition of the reaction solution after a certain oil passage time. The results are also shown in Table 2. According to the results shown in Tables 1 and 2, it can be seen that the ZSM-5 catalyst has a higher selectivity for ditolylmethane than the silica-alumina catalyst. It can also be seen that the rate at which the catalyst activity decreases is smaller for the ZSM-5 catalyst.

Comparative Example 2 Contents [4 moles of toluene in 11 separable flasks,
Two moles of diphenylmethane and 10 g of aluminum chloride as a catalyst were added, and the mixture was stirred at room temperature for 5 hours. After deactivating the catalyst, the reaction solution was analyzed in the same manner as in the example, and the results were as shown in Table 3 below. As is clear from the results in Table 3, using aluminum chloride as a catalyst has the disadvantage that the reaction solution contains a large amount of ditolylmethane and heavy components. Comparative Example 3 In a reaction vessel with an internal capacity of 250 ml, 20 hydrogen-type Y-type zeolite (manufactured by Union Carbide, 12-14 mesh) was added.
It was filled with 0 ml and dried at 480° C. for 3 hours while supplying dry nitrogen. Under the reaction conditions of reaction temperature 180°C, pressure 20 atm (under nitrogen atmosphere), and LHSV = 1.0,
A mixture of mole to 1 mole of diphenylmethane was passed through the oil.

The oil-passed reaction solution was analyzed by gas chromatography using the Durum method.
The composition of the reaction solution after passing through the oil for a period of time was analyzed. The results are also shown in Table 3.

According to these results, Y-type zeolite has a low selectivity for ditolylmethane and a significant decrease in activity.

This decrease in activity could not be recovered even if the reaction temperature was raised from 180°C to 260°C.

Claims (5)

[Claims] (1) Using a crystalline synthetic zeolite catalyst in which the SiO_2/Al_2O_3 molar ratio is 20 or more and the entrance of the main cavity has a 10-membered oxygen ring, the reaction temperature is 170 to 40.
A method for producing ditolylmethane, which comprises reacting toluene with diphenylmethane, benzyltoluene, or a mixture thereof at a temperature of 0°C. (2) The method for producing ditolylmethane according to claim 1, wherein the crystalline synthetic zeolite catalyst is a ZSM-5 type catalyst. (3) The method for producing ditolylmethane according to claim 2, wherein the ZSM-5 type catalyst is ZSM-5. (4) The method for producing ditolylmethane according to claim 1, wherein the molar ratio of toluene to be supplied to the reaction system to diphenylmethane, benzyltoluene, or a mixture thereof is 0.5 to 20. (5) The method for producing ditolylmethane according to claim 1, wherein the reaction temperature is 200 to 350°C.