JP2911263B2 - Method for producing 2-methylnaphthalene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing 2-methylnaphthalene (hereinafter abbreviated as 2-MN) by isomerizing 1-methylnaphthalene (hereinafter abbreviated as 1-MN). 2-MN is a compound that is useful as a synthetic intermediate for dyes, pharmaceuticals, and the like, and has recently attracted attention as a synthetic intermediate for 2,6-naphthalenedicarboxylic acid, which is a highly functional resin raw material. .

[0002]

2. Description of the Related Art Since 2-MN is contained in a methylnaphthalene fraction obtained by distilling a tar component produced by dry distillation of coal, a basic substance has conventionally been extracted from the methylnaphthalene fraction. After that, it was recovered by crystallization or distillation. The methylnaphthalene fraction after removal of the basic substance, which is a crystallization and distillation raw material, contains 2-
Since 1-MN is contained in a large amount together with MN, naturally, 1-MN is also contained in the residual liquid after crystallization or distillation of 2-MN.
N is present in large amounts. Although 1-MN has a use as a dye or the like, it has less industrial demand than 2-MN. For this reason, 1-MN contained in the residual liquid after crystallization or distillation of 2-MN or in the crystallization or distillation raw material is reduced to 2-MN.
A technique for obtaining 2-MN by isomerization to MN is desired, and several methods have been conventionally proposed.

[0003] It is known that the isomerization reaction of an alkyl aromatic compound is promoted by an acid catalyst.
₃ , a method using a homogeneous acid catalyst such as HF-BF ₃ or a heterogeneous acid catalyst such as silica / alumina, zeolite, or modified zeolite can be considered. As an example using a homogeneous acid catalyst, an example in which BF ₃ —H ₃ PO ₄ is used to improve 2-MN selectivity is disclosed in Japanese Patent Publication No. H01-13454. On the other hand, as an example of using a heterogeneous acid catalyst, an example of improving the selectivity of 2-MN using a partially ion-exchanged Y-type zeolite is described in the literature (Applied Catalysis, V. Solinas et al.).
9, 1984, pp. 109-117).

[0004]

The conventionally known method for isomerizing 1-MN is as described above. However, when the BF ₃ -H ₃ PO ₄ catalyst is used as a homogeneous catalyst, for example, there is a risk of injury or poisoning in handling the catalyst, and H ₃ PO _{4 in} this catalyst is Although it can be reused,
Expensive BF ₃ is dissolved in water while being dissolved in the product. As described above, in the case of the homogeneous catalyst, not only there is a danger in handling the catalyst itself, but also there are difficulties in recovering the catalyst.

On the other hand, as described above, as a heterogeneous catalyst,
For example, a method of performing an isomerization reaction using silica / alumina, zeolite, modified zeolite, or the like can be considered.
However, for example, the above-mentioned Solinas et al. Document the time course of the activity when a partially ion-exchanged Y-type zeolite is used. It is not considered applicable to industrial production. As described above, when isomerization of 1-MN is performed using a solid and acidic heterogeneous catalyst, during the reaction, deterioration of the catalyst due to carbonaceous precipitation is remarkable, and the catalyst activity decreases rapidly. There was a problem that would occur.

As described above, in the method for producing 2-MN by the isomerization reaction of 1-MN, a method using a heterogeneous catalyst which is easy to handle and recover and has a long life is known. And such a method has been eagerly awaited. The present invention has been made in response to such demands of the industry, and provides a method for producing 2-MN by isomerization reaction of 1-MN using a heterogeneous catalyst having a long life. Aim.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have studied Y-type zeolites having various SiO ₂ / Al ₂ O ₃ ratios as a catalyst used in the isomerization reaction of 1-MN. It has been found that a Y-type zeolite having a larger SiO ₂ / Al ₂ O ₃ ratio has more excellent activity persistence.

[0008] Therefore, it was further studied how much Y-type zeolite is suitable as SiO ₂ / Al ₂ O ₃ , and the optimum temperature of this isomerization reaction was also studied.

As a result, de-Al is performed and the lattice constant is reduced to 2
Y-type zeolite reduced to 4.37 ° or less
When used in the 1-MN isomerization reaction performed at a temperature of 600 ° C., it was found that the activity was remarkably persistent, and the present invention was completed.

That is, according to the present invention, in producing 2-methylnaphthalene by isomerizing 1-methylnaphthalene, a catalyst having a lattice constant of 24.37 ° or less is used as a catalyst.
A method for producing 2-methylnaphthalene, characterized in that a reaction is performed in a temperature range of 350 to 600 ° C. using a type zeolite.

Here, the composition of the Y-type zeolite used (SiO
The limitation of the ( ₂ / Al ₂ O ₃ ratio) depends on the lattice constant. It is known that the Y-type zeolite generally decreases in lattice constant as the Al content in the lattice decreases. This is because the lattice constant can be used as an index of the Al content in the lattice. Note that the relationship between the Al content and the lattice constant constituting the lattice in the Y-type zeolite is as follows.
For example, literature (H. FichtnerSchmittler et al., Crystal Resear
ch and Technology, 19, 1984, 1, K1-K3)
Is shown in

Hereinafter, the present invention will be described in detail. In the production method of the present invention, the compound used for the isomerization reaction is 1-methylnaphthalene (1-MN).

In the present invention, 1-M used as a raw material
N need not be pure, but may include, for example, 2-MN less than the equilibrium concentration [2-MN / (1-MN + 2-MN) = 65%]. In addition, impurities such as naphthalene may be mixed.

Specifically, 1-MN-containing oils such as coal tar fractions and petroleum fractions containing 1-MN, more specifically, after removing basic substances containing 1-MN and 2-MN From the methyl naphthalene fraction or from the methyl naphthalene fraction
Examples include residual liquid after crystallization or distillation of -MN, and these are used as raw materials.

The 1-MN-containing oil used as a raw material is industrially preferably one having a 1-MN content of 10% by weight or more, particularly preferably 20% by weight or more.

The catalyst used in the present invention has a lattice constant of 24.37.
Ｙ The following Y-type zeolite. As described above, the lattice constant of the Y-type zeolite indicates the composition of the lattice constituent elements. Then, the document (Crystal Rese
According to arch and Technology, 19), when the Al removal of the Y-type zeolite is successively performed deeply, the value of the lattice constant extrapolated to the Al content of 0% is 24.2%.
A Y-type zeolite having a lattice constant of 24.2 ° or less does not exist theoretically. Therefore, the Y-type zeolite having a lattice constant of 24.37 ° or less used in the present invention refers to a zeolite that has been thoroughly dealuminated and has a very large SiO ₂ / Al ₂ O ₃ ratio.

The Y-type zeolite used as a starting material for obtaining such a Y-type zeolite having a lattice constant of 24.37 ° or less may have any SiO ₂ / Al ₂ O ₃ ratio. However, if a commercially available USY (ultra-stabilized Y-type) zeolite having a higher SiO ₂ / Al ₂ O ₃ ratio is used, the subsequent Al removal can be performed smoothly.

Further, in the Y-type zeolite to be subjected to Al removal, all or some of the cation sites must be exchanged with protons or ammonium ions.

The Y-type zeolite, which is the starting material, has a lattice constant
In order to reduce the temperature to 24.37 ° or less, Al may be removed by steam treatment and / or acid treatment.

The steam treatment may be performed in steam or in a mixed atmosphere of steam and another gas.

The processing temperature for performing the steam processing is 400
To 1000 ° C, preferably 500 to 800 ° C. If the processing temperature is too low, the effect on the removal of Al is small, and the lattice constant is not reduced, while if the processing temperature is too high,
The zeolite crystals collapse, leading to a decrease in crystallinity and catalytic activity. Further, when this treatment is performed in high-temperature steam, a container having high heat resistance and corrosion resistance is required, which is economically disadvantageous.

The acid treatment is usually carried out after the steam treatment for the purpose of removing Al which has come out of the crystal lattice by the steam treatment. However, even if the acid treatment is carried out alone, the Al removal by the steam treatment is sufficient. If it is performed in the above, it is not necessary to perform it.

The acid treatment can be carried out using a mineral acid or the like. For example, when the Al treatment is carried out with hydrochloric acid, the Y-type zeolite is suspended in a 0.1 to 5N hydrochloric acid aqueous solution and stirred. I just need. If the hydrochloric acid concentration at this time is too low, Al removal is not sufficiently performed, while if it is too high, Y
The crystallinity of the type zeolite decreases, and the catalytic activity decreases. Further, if this treatment is performed in strong hydrochloric acid, a container having high corrosion resistance is required, which is economically disadvantageous.

As described above, a long-life catalyst is obtained by subjecting the Y-type zeolite to steam treatment and / or acid treatment and removing Al from the lattice. Although the reason is not clear, the crystal form of the Y-type zeolite is destroyed in the process of de-Al, and the activity is not easily reduced even if carbonaceous material is precipitated. It is conceivable that, when used as a catalyst, the deposition of carbonaceous material is suppressed.

[0025] Further, Y-type zeolite having a lattice constant of 24.37 ° or less is obtained by such Al removal treatment.
-Low persistence of catalytic activity in the MN isomerization reaction. And, as the SiO ₂ / Al ₂ O ₃ ratio increases, that is, the lattice constant decreases, the 1-MN
Shows high activity persistence in the isomerization reaction of

Excessive removal of Al by steam treatment and / or acid treatment results in crystal collapse, reduction of active sites, etc., resulting in a problem that the activity persistence is high but the activity level is low. However, in the present invention, such a Y-type zeolite can also be used as a catalyst. In such a case, when performing the isomerization reaction, measures such as reducing the flow rate of the raw material 1-MN per unit weight of the catalyst may be taken. Thereby, a high conversion rate and a highly sustainable reaction result can be obtained.

As a catalyst used in the 1-MN isomerization reaction,
Lattice constant is 24.37 ° or less, preferably 24.27 to 24.35
The use of Y-type zeolite in the range of {, more preferably in the range of 24.28 to 24.34} makes it possible to achieve both high activity and long-lasting activity.

The Y-type zeolite used in the present invention is:
Although the lattice constant is 24.37 ° or less, Y-type zeolite having a lattice constant exceeding 24.37 ° may be mixed as long as the gist of the present invention is not impaired.

For other purposes, for example, fluid catalytic cracking (F
CC) and other catalysts containing a Y-type zeolite and having a lattice constant of 24.37 ° or less in an FCC reaction tower or a regeneration tower having a thermal history or the like in 1-M
When used in an N isomerization reaction, it provides good activity persistence.

According to the present invention, 2-MN is produced by isomerizing 1-MN using a Y-type zeolite having a lattice constant of not more than 24.37 ° obtained as described above as a catalyst. The temperature is 350-600 ° C, preferably 400-500 ° C, more preferably 420-480.
° C.

On the Y-type zeolite which has been highly de-Al-deposited, there are active sites which are active at a low temperature with respect to the 1-MN isomerization reaction but are rapidly deteriorated. There are two types of high active sites,
This has been clarified by the study of the present inventors.

When the 1-MN isomerization reaction is carried out using the catalyst at a reaction temperature of less than 350 ° C., only the activity derived from the high-temperature active site remains because the low-temperature active site undergoes short-term degradation at the beginning of the reaction. However, the reaction temperature is low due to the low temperature, and a sufficient conversion cannot be obtained. If the reaction temperature is moderately high, a sufficiently high conversion by the high-temperature active site can be obtained even after the initial deterioration of the catalytic activity (activity derived from the low-temperature active site), but it is too high (more than 600 ° C.).
Then, the carbonaceous formation rate increases, and the catalyst deteriorates faster. If the reaction temperature is too high, many side reactions occur,
There is a problem that a large amount of by-products such as naphthalene and dimethylnaphthalene are generated, which is not preferable.

In the production method of the present invention, the 1-MN isomerization reaction may be carried out by a flow system or a batch system, but the flow system is more suitable for industrial production, It is also advantageous.

The reaction may be performed in a gas phase or a liquid phase.

When the reaction is carried out in the liquid phase, the carbonaceous precursor deposited on the catalyst surface can be dissolved and removed in the liquid, so that the catalyst life is prolonged. On the other hand, the boiling point of 1-MN ( In order to carry out the reaction at a temperature of 245 ° C. or higher, the pressure must be increased in order to maintain the liquid phase, the equipment must be pressure-resistant, and the power cost increases.

When the reaction is carried out in the gas phase, the reaction can be carried out under normal pressure or a pressure close to normal pressure, so that the pressure resistance of the equipment becomes unnecessary and the power cost is reduced. There is a disadvantage that deterioration due to deposition of the material is fast, and in some cases, a dilution gas cost is required. In the reaction in the gas phase, nitrogen, water vapor, hydrogen, or the like may be used as a diluent gas or nothing may be used.However, in order to further increase the activity persistence, hydrogen is used as a diluent gas. It is preferably used.

In the manufacturing method of the present invention, the WHS
V (the weight of 1-MN passing over a unit weight of catalyst per hour) is preferably in the range of 0.1 to 10 h ^-1 . WHS
If V is too large, a sufficiently large conversion cannot be obtained. On the other hand, if WHSV is too small, the amount of the charged catalyst and the volume of the reactor become large, which is uneconomical.

According to the method described above, 1-MN can be isomerized to obtain 2-MN, but the catalyst used can be regenerated. Specifically, the catalyst degraded by carbonaceous deposition from the reaction system, in air or oxygen, etc.
When calcined at about 300 to 800 ° C., the catalyst can be regenerated.

Further, by supporting a group VIII metal ion such as Fe, Co, Pd and Pt by ion exchange or the like, it is possible to delay the decrease in the activity of the catalyst.

[0040]

Next, the present invention will be described with reference to examples and comparative examples. The measurement of the zeolite lattice constant in the examples was performed by XRD (X-ray diffraction) under the following conditions, and was calculated from the peak position of the (533) plane. Target / filter: Co / Fe Voltage / current: 50 kV / 30 mA Irradiation side slit: 1.0 DEG Anti-scattering line slit: 1.0 DEG Receiving side slit: 0.3 mm Measurement resolution: 0.02 DEG Preset time: 0.4 sec Detector: Scintillation counter Model: Rigaku Corporation RAD-IIA type

Example 1 SiO ₂ / Al ₂ O ₃ (molar ratio) = 4.
5 g of Y-type zeolite (lattice constant = 24.63 °) in which 9 cation sites were exchanged with protons was packed in a stainless steel reaction tube and treated at 600 ° C. in a 100% steam atmosphere for 6 hours. The volume of water sent during this period was 200 ml. The Y-type zeolite subjected to the above treatment had a lattice constant of 24.28 °. After the treatment, the Y-type zeolite 0.1.
5 g was packed in a stainless steel reaction tube, and hydrogen was added at 450 ° C. and 20 N./min. T. P. Then, 0.75 g of 1-MN (manufactured by Tokyo Chemical Industry Co., Ltd., reagent grade) was supplied per hour, and the isomerization reaction was performed under normal pressure. The 1-MN conversion was measured over time and the results are shown as A in FIG. The selectivity of converted 1-MN to 2-MN in this experiment remained almost constant at about 90%.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the same Y-type zeolite as in Example 1 (lattice constant = 24.63 °) was used without performing steam treatment. Reaction, the 1-MN conversion is measured over time,
The result is shown as B in FIG. The selectivity of converted 1-MN to 2-MN in this experiment remained almost constant at about 90%.

(Example 2) A starting zeolite obtained by ion-exchanging cation sites of a Y-type zeolite ZCP-50 manufactured by Catalysis Kasei Kogyo with protons (lattice constant =
Steam treatment was performed under the same conditions as in Example 1 except that 24.65 °) was used. The lattice constant of the Y-type zeolite after the steam treatment was 24.30 °. Using the Y-type zeolite after this treatment, an isomerization reaction was carried out under the same conditions as in Example 1, and 1
The -MN conversion and the 2-MN yield were measured over time, and the results are shown in Table 1.

Comparative Example 2 The same procedure as in Example 2 was repeated except that the same Y-type zeolite as that of Example 2 (after ion exchange) was used without performing steam treatment. A 1-MN conversion and a 2-MN yield were measured over time, and the results are shown in Table 1.

Example 3 As a starting zeolite, the lattice constant was set to 24.38 ° by steam treatment (first time).
Using a Y-type zeolite in which the cation sites were exchanged with protons, the zeolite was further subjected to a steam treatment (second time) under the same conditions as in Example 1. The lattice constant of the Y-zeolite after the second steam treatment was 24.29 °. The isomerization reaction was performed under the same conditions as in Example 1 using the Y-type zeolite after this treatment, and the 1-MN conversion and the 2-MN yield were measured over time, and the results are shown in Table 1.

Comparative Example 3 Except that the first steamed Y-type zeolite (lattice constant = 24.38 °) used as the starting zeolite in Example 3 was used without performing the second steaming. Performed the 1-MN isomerization reaction in the same manner as in Example 3, and measured the 1-MN conversion and the 2-MN yield over time. The results are shown in Table 1.

Example 4 An isomerization reaction was carried out under the same conditions as in Example 1 by using steam-treated Y-type zeolite having a lattice constant of 24.34 ° as a catalyst. The 1-MN conversion and the 2-MN yield were measured over time, and the results are shown in Table 1.
It was shown to.

Example 5 1-MN isomerization was carried out in the same manner as in Example 3 except that the reaction temperature was changed to 410 ° C., and the 1-MN conversion and the 2-MN yield were measured with time. And the results are shown in Table 1.

Example 6 1-MN isomerization was carried out in the same manner as in Example 3 except that the reaction temperature was changed to 490 ° C., and the 1-MN conversion and the 2-MN yield were measured over time. And the results are shown in Table 1.

(Example 7) Using the Y-type zeolite (lattice constant = 24.29 °) prepared in Example 3 as a catalyst, 1-MN isomerization was carried out under the following conditions. That is, 2 g of the catalyst was packed in a stainless steel reaction tube, and 1-M
N 3 g / h, 50 kg / cm ² without accompanying gas
The isomerization reaction was performed in the liquid phase under the pressure of G. 1-
The MN conversion and the 2-MN yield were measured over time, and the results are shown in Table 1.

Comparative Example 4 The same procedure as in Example 7 was repeated except that the same Y-type zeolite as in Example 1 (lattice constant = 24.63 °) was used as a catalyst without performing steam treatment.
-MN isomerization reaction was performed to obtain 1-MN conversion and 2
The -MN yield was measured over time, and the results are shown in Table 1.

[0052]

[Table 1]

From Table 1, the following matters are clear. That is, when a Y-type zeolite having a lattice constant of 24.37 ° or less was used, the catalytic activity was clearly maintained as compared with the case where a zeolite having a lattice constant exceeding 24.37 ° was used. Comparison between Example 3 and Comparative Example 3 and Comparison between Example 7 and Comparative Example 4). Further, the reaction temperature in the isomerization reaction of 1-MN is most preferably around 450 ° C. (Example 3), and the catalytic activity decreases even at a higher temperature (Example 6) or a lower temperature (Example 5). Etc., the reactivity was reduced. Note that comparing the data of Example 5 with the data of Comparative Example 3,
In the reaction time of 5 hours and 10 hours, Comparative Example 3 has a better value, but this is based on the difference in the reaction temperature (reaction temperature: Comparative Example 3> Example 5). When the reaction time is 20 hours or more, the value of Example 5 is better, and it is clear that the Y-type zeolite used in the present invention is more excellent in sustaining the catalytic activity.

[0054]

According to the present invention, 2-MN isomerized by 1-MN using a heterogeneous catalyst having a long life.
Are provided. In the present invention, since the 1-MN isomerization reaction is performed using a solid catalyst with little deterioration, the cost and operation required for the regeneration or replacement of the catalyst are small, and the 2-MN synthesis is performed efficiently. Therefore, according to the present invention, 1-MN is effectively used.

[Brief description of the drawings]

FIG. 1 is a graph showing the change over time in 1-MN conversion in Example 1 (A) and Comparative Example 1 (B).

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-120028 (JP, A) US Patent 3,876,630 (US, A) Journal of Japan Petroleum Institute, Vol. 33, No. 4 (1990. 7) p. 214-22 (58) Field surveyed (Int.Cl. ⁶ , DB name) C07C 15/24 B01J 29/08 C07C 5/27

Claims (2)

(57) [Claims] The method according to claim 1 1-methylnaphthalene in producing 2-methylnaphthalene by isomerization, as a catalyst, the following Y-zeolite lattice constant 24.37A, N
A method for producing 2-methylnaphthalene, wherein i is used without being supported , and the reaction is carried out in a temperature range of 350 to 600 ° C. 2. A method for producing 2-methylnaphthalene by isomerizing 1-methylnaphthalene, wherein the catalyst has a lattice constant of 24.37 ° or less by a steam treatment and / or an acid treatment in a temperature range of 400 to 1000 ° C. as a catalyst. A method for producing 2-methylnaphthalene, comprising using the Y-type zeolite described above without carrying Ni , and performing the reaction in a temperature range of 350 to 600 ° C.