JPH064546B2 - Method for producing mono- and / or dialkylnaphthalene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for alkylating naphthalene and / or alkylnaphthalene. More specifically, it relates to a method for producing a mono- and / or di-alkylated naphthalene by alkylating naphthalene and / or alkylnaphthalene, particularly β-methylnaphthalene, with an alkylating agent using a specific phosphasite type zeolite. .

[Conventional technology]

A method of alkylating an aromatic compound using a Lewis acid such as AlCl ₃ as a catalyst is known as Friedel-Crafts reaction. In particular, a method for obtaining isopropylnaphthalene by alkylating naphthalene with propylene is well known in the art. However, this alkylation method is economically disadvantageous because it is necessary to separate the reaction product and the catalyst after completion of the reaction, and the catalyst has a property of corroding the apparatus.

On the other hand, a method of methylating naphthalene compounds using a solid acid catalyst such as zeolite has not been known so far.

The present inventors have conducted the methylation reaction of naphthalene compounds using various zeolites, and found the following. That is, when the alkylation reaction of β-methylnaphthalene was carried out using ZSM-5 zeolite, the conversion rate of β-methylnaphthalene was remarkably low. ZSM-5 is often used in the alkylation reaction of benzene compounds, and good results are obtained. However, in the alkylation reaction of a naphthalene compound having a larger molecular diameter than that of a benzene compound, the pore size of ZSM-5 is too small, and therefore the diffusion of the naphthalene compound as a raw material into the pores is hindered. Conceivable.

Further, when mordenite was used as a catalyst, the initial conversion of β-methylnaphthalene was quite high, but it had a drawback that the activity was significantly deteriorated.

On the other hand, when the methylation reaction of β-methylnaphthalene is carried out in the presence of a saturated alicyclic hydrocarbon compound using Y-type zeolite, which is a faujasite-type zeolite, as a catalyst, the conversion rate is high and the activity deterioration is remarkably improved. It However, with the above-mentioned mordenite, the deterioration of the activity of the methylation reaction could not be improved even when the mordenite was used in the presence of a saturated alicyclic hydrocarbon compound. Therefore, the effectiveness of Y-type zeolite is accepted.

However, the conversion rate was not high enough to satisfy the inventors of the present invention with conventional Y-type zeolite, that is, Y-type zeolite in which Na cations are simply exchanged for hydrogen ions.
In addition, although the activity deterioration was improved, it was not yet sufficient.

More importantly, dimethylnaphthalene obtained by methylating β-methylnaphthalene (hereinafter referred to as DMN)
The isomer mixture of 1 has a high content of 1,2-dimethylnaphthalene, and the content of 1,2-dimethylnaphthalene increases with time.

The useful isomers of dimethylnaphthalene are 2,6- or 2,
It is 7-dimethylnaphthalene. In particular, when 2,6-dimethylnaphthalene is oxidized, 2,6-naphthalenedicarboxylic acid is obtained, and the polyester obtained from this carboxylic acid has a wide range of uses such as synthetic fibers and films. Dimethylnaphthalene has 10 isomers, and it is known that isomerization in the following series occurs relatively easily due to intramolecular rearrangement.

(4) 1,2-DMN (Note) DMN; dimethylnaphthalene As described above, it is difficult to convert 1,2-dimethylnaphthalene into other isomers. Therefore, in the methylation reaction of β-methylnaphthalene, It is important to suppress the production of 1,2-dimethylnaphthalene.

[Problems to be solved by the invention]

A method for alkylating naphthalene and / or alkylnaphthalene using a solid acid catalyst to produce a mono- and / or dialkylnaphthalene, particularly a method for producing dimethylnaphthalene, which has a high conversion rate and a long active life of the catalyst,
Moreover, a production method in which 1,2-dimethylnaphthalene is reduced has not been established yet. Therefore, the present invention provides a method for producing mono- and / or dialkylnaphthalene, particularly dimethylnaphthalene, which has excellent activity, and further suppresses the production of 1,2-dimethylnaphthalene while maintaining high activity for a long time. It is intended.

[Means to try to solve problems]

The present inventors continued their earnest research on a method for alkylating naphthalene and / or alkylnaphthalene. As a result, it is possible to obtain a remarkably high conversion rate by using, as a catalyst, a dealuminaized phosphasite type zeolite, particularly a Y type zeolite, and to carry out the alkylation reaction in the presence of a saturated alicyclic hydrocarbon compound. It was discovered that by doing so, a high conversion rate can be maintained without activity deterioration.

Furthermore, they have surprisingly found that the content of 1,2-dimethylnaphthalene in a mono- and / or dialkylnaphthalene mixture can be suppressed to a low level, and the increase over time can also be suppressed, thereby completing the present invention.

That is, the present invention is characterized in that in the presence of a dealuminaized faujasite-type zeolite and a saturated alicyclic hydrocarbon compound, naphthalene and / or alkylnaphthalene and an alkylating agent are reacted with each other, and / or The present invention relates to a method for producing dialkylnaphthalene.

Hereinafter, the method of the present invention will be described in more detail.

The phaujasite-type zeolite used in the present invention is Y
Type or X type zeolite is preferable, and Y type zeolite is particularly preferable. As the Y-type zeolite, both natural zeolite and synthetic zeolite can be used. The cation site of zeolite is usually occupied by an alkali metal such as Na. When used in the reaction, the alkali metal is exchanged for hydrogen ion before use. Similarly, in Y-type zeolite, ions are also exchanged, but at this time, Na is treated by heat treatment in the presence of steam or treatment with dilute mineral acid.
It is well known in the art that the ₂ O content is 1% by weight or less and the hydrothermal stability is remarkably improved. In the preparation of the dealuminized zeolite shown in the present invention, it is preferable to use such Y-type zeolite having a stabilized crystal structure. This is because the crystallinity of the Y-type zeolite is easily broken during the dealuminizing process or the subsequent calcination process in the conventional Na-type or H-type in which a considerable part thereof is subjected to hydrogen ion exchange. Therefore, it is preferable that the Y-type zeolite is subjected to dealumination treatment after the stability of its crystal structure is enhanced.

The Y-type zeolite having improved crystal structure stability can be obtained by a known technique (Japanese Patent Laid-Open No. 54-122700, Japanese Patent Laid-Open No. 56-22624, etc.). An example is shown below.

The starting Y-type zeolite containing Na is 50 to 7 of Na.
Treat with aqueous ammonium salt solution such that 0% is replaced by ammonium. As the ammonium salt that can be used for ion exchange, chloride, nitrate, sulfate, carbonate, acetate and the like can be used, and chloride and sulfate are particularly preferable. When the ion exchange rate of the alkali metal to ammonium does not reach 50 to 75% in one ion exchange treatment, it is necessary to repeat the same treatment as above a plurality of times.

The Y-type zeolite in which 50 to 75% of Na has become ammonium type by the above ion exchange treatment is then heat-treated in the presence of water vapor at a high temperature (for example, 400 to 900 ° C.) for 10 minutes to 5 hours. The faujasite-type zeolite heat-treated in the presence of hydrogen gas is again treated with an aqueous ammonium salt solution, and subsequently in the presence of steam at a high temperature (for example, 400 to
When heat-treated at 900 ° C. for 10 minutes to 5 hours, an H-type zeolite having improved crystal structure stability can be obtained. The stability of the crystalline structure can also be imparted by treating with an aqueous solution of ammonium salt, further heat treating, and then treating with dilute mineral acids several times. In this case, in order to prevent the destruction of the crystal structure, the concentration of mineral acids is 1.0 to 5.0 at pH value.
It is necessary to adjust the range.

The Y-type zeolite having an improved crystal structure stability is then treated with an inorganic acid or an organic acid, and subjected to a dealumination treatment. The rate of increase in the molar ratio of silica to alumina after the acid treatment changes depending on the hydrogen ion concentration during the acid treatment, the treatment temperature, and the treatment time. Of these, the effect of hydrogen ion concentration is the greatest, and the pH value of the hydrogen ion concentration during acid treatment is 0.1
It is preferable to adjust to the range of 4.0. The processing conditions are
Generally, when the pH value during the acid treatment is 0.1 to 4.0, the treatment temperature is 10 to 95 ° C., and the treatment time is 30 minutes to 30 hours. A batch method is preferable as a treatment method, and a method of bringing the acid into contact with zeolite as an aqueous solution is preferable.
When the batch method is used, the solid-liquid ratio is preferably 1-30.

The acid that can be used for the acid treatment may be either an inorganic acid or an organic acid. As the inorganic acid, for example, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid or the like can be used, and as the organic acid, carboxylic acid, sulfonic acid or the like can be used. Particularly in the case of an organic acid, an aliphatic carboxylic acid is preferable because of easy pH adjustment. For example, acetic acid, oxalic acid, succinic acid, maleic acid and the like are preferable.

When the molar ratio of silica to alumina of the phosjasite type zeolite does not reach the target value in one treatment,
It is also possible to repeat the same processing as described above a plurality of times.

The acid-treated phosphasite-type zeolite is thoroughly washed with ion-exchanged water, and then heat-treated in the presence of air at a high temperature (for example, 400 to 600 ° C.) for 2 to 6 hours to be subjected to a dealumination treatment. It can be a phosphasite type zeolite.

The molar ratio of silica to alumina in the dealuminaized faujasite-type zeolite used in the present invention is preferably in the range of 6.5 to 150. By setting the molar ratio of silica to alumina to 6.5 or more, the effect of suppressing the production of 1,2-dimethylkirnnaphthalene shown in the present invention becomes particularly high, while setting it to 150 or less is sufficient in the zeolite. This is because there is a large amount of acid and there is a tendency to increase the conversion rate of the raw material naphthalene and / or alkylnaphthalene.

The zeolite used in the present invention can also be used in powder form itself. Also, by compression molding, it can be used as a pellet-shaped or tablet-shaped molded article. When used as a molded product, alumina sol, silica sol or the like may be added as a binder to form a molded product.

The alkylation reaction of naphthalene and / or alkylnaphthalene is carried out in the presence of a saturated alicyclic hydrocarbon compound supplied to the reaction system. By this, the activity deterioration of the catalyst can be remarkably improved. As the saturated alicyclic hydrocarbon compound, a monocyclic compound, a polycyclic compound not sharing a ring carbon, a polycyclic compound sharing a ring carbon, a condensed alicyclic compound, a bridged alicyclic compound Can be mentioned. . Specific examples of the monocyclic compound include cyclohexane, cycloheptane, cyclooctane and cyclodecane. Examples of the polycyclic compound not sharing a ring carbon include bicyclopropyl, bicyclopentyl, bicyclohexyl, cyclopentylcyclohexane and the like. As a polycyclic compound sharing a ring carbon, there is a so-called spirane compound, for example, spiro [2,2] pentane, spiro [2,
3] hexane, spiro [2,4] peptane, spiro [3,
3] Peptane, spiro [3,4] octane and the like. Examples of the condensed alicyclic compound include bicyclo [4,2,0] octanehydroindane, decalin, perhydrophenanthrene, perhydroanthracene and the like. As the bridged alicyclic compound, norpinane, norbornane,
Examples include bicyclo [2,2,1] octane. Among these, particularly preferable compounds include condensed alicyclic compounds and polycyclic compounds, and specifically, decalin and bicyclohexyl can be mentioned. Decalin includes cis-decalin and trans-decalin, and the effects of the present invention are exhibited regardless of which is used. Therefore, it is preferable to use the mixture because the mixture of both can be obtained at low cost.

The supply amount of the saturated alicyclic hydrocarbon compound is preferably in the range of 0.1 to 20 weight ratio with respect to naphthalene and / or alkylnaphthalene. In particular, the range of 0.2 to 10 weight ratio is suitable. This is because when the content is in this range, activity deterioration can be sufficiently prevented and high productivity can be maintained.

The alkylation reaction of naphthalene and / or alkylnaphthalene according to the present invention can be carried out in either a gas phase or a liquid phase. The alkylation reaction is carried out under atmospheric pressure to increased pressure, but generally atmospheric pressure to 100 kg / cm ² G, particularly atmospheric pressure to 20 kg / cm ² G is suitable. Reaction temperature is 150-5
It is suitable that the temperature is 00 G, preferably 200 to 400 ° C.

When the reaction is carried out in the gas phase, it is preferably carried out under a hydrogen stream in order to prolong the active life. It is preferable to supply hydrogen in the range of 0.1 to 10 molar ratio with respect to naphthalene and / or alkylnaphthalene.
Moreover, you may introduce gas, such as nitrogen, carbon dioxide, and methane. The reaction is usually carried out using a fixed bed reactor,
It is also possible to use a fluidized bed or a moving bed. At this time, the weight hourly space velocity (WHSV) is 0.2 to 50 Hr ^-1.
Can be performed in the range of. More preferably WHS
V is in the range of ¹ to 20 Hr ^-1 . By setting WHSV to 1 or more, high productivity can be maintained, and WH
This is because by setting the SV to 50 Hr ^-1 or less, the contact time with the catalyst can be made sufficiently long and a high conversion rate can be obtained. The WHSV in the present invention means the supply amount (g) of naphthalene and / or alkylnaphthalene per unit time (Hr) per catalyst (g).

Examples of the alkylating agent used in the alkylation reaction include alcohols represented by the general formula C _n H _{2n + 1} OH (n = 1 to 4) and general formula (C _n H _{2n + 1} ) ₂ O (n = The ethers represented by 1 to 4) are mentioned, for example, methanol, ethanol, iso-propanol and dimethyl ether are preferable, and these can be used alone or as a mixture. The amount of the alkylating agent supplied is preferably in the range of 0.2 to 2.0 molar ratio with respect to naphthalene and / or alkylnaphthalene.

In the present invention, the alkylnaphthalene is preferably methylnaphthalene when the alkylation is methylation.

〔The invention's effect〕

According to the present invention, in the alkylation reaction of naphthalene and / or alkylnaphthalene, a high conversion rate of a raw material is obtained by using a dealumina-treated phosphite-type zeolite as a crystalline aluminosilicate, particularly a Y-type zeolite as a catalyst. Can be achieved. Further, by carrying out the alkylation reaction in the presence of a saturated alicyclic hydrocarbon compound, the active life is also remarkably improved.

As shown in the comparative example described later, in ZSM-5, an extremely low conversion rate is obtained even when the reaction temperature is increased to 450 ° C. With mordenite, although the initial conversion rate is considerably high, the activity deterioration is extremely large. In addition, in the case of a normal Y-type zeolite, that is, a Y-type zeolite in which Na cations are simply exchanged for hydrogen cations, the conversion rate is not so high as to satisfy the present inventors, and the activity deterioration can be greatly improved, but the activity deterioration is still considerable. Recognized and not sufficient.

In contrast, the inventive examples provide much higher conversions than the prior art. Moreover, no activity deterioration was observed and high activity was maintained. More importantly, the formation of 1,2-dimethylnaphthalene is considerably suppressed, especially in the isomer mixture of dimethylnaphthalene obtained by the methylation of naphthalene and / or methylnaphthalene. Furthermore, the increase of 1,2-dimethylnaphthalene over time can be suppressed.

〔Example〕

Examples of the present invention will be shown below, but the present invention is not limited thereto.

Example 1 100 g of Y-type zeolite (TSZ-305 manufactured by Toyo Soda Co., Ltd.) containing 11.8% by weight of Na ₂ O was suspended in 1N aqueous ammonium chloride solution 1. This was stirred at 95 ° C. for 6 hours, filtered, and thoroughly washed with ion-exchanged water. As a result of measuring the amount of sodium eluted in the aqueous solution by atomic absorption spectrometry, 70% of sodium cations were exchanged for ammonium. This Y-zeolite is 1 at 110 ° C
It was dry day and night. Then, this Y-type zeolite was placed in a quartz tube and allowed to pass steam to be heat-treated at 700 ° C. for 1 hour.

Next, 100 g of the heat-treated Y-type zeolite was suspended in 1N aqueous ammonium chloride solution 1 and stirred at 95 ° C for 6 hours. Then, the Y-type zeolite was separated by filtration and washed thoroughly with deionized water. This Y-type zeolite is 110 ℃
Then, dry it overnight and put it in a quartz tube to allow water vapor to flow.
It heat-processed at 0 degreeC for 1 hour. This product contained 0.3% by weight of Na ₂ O (HY zeolite).

(a) The HY zeolite was suspended in a 1N hydrochloric acid solution, stirred at 95 ° C. for 4 hours, filtered and separated, and washed sufficiently with ion-exchanged water. Then, after drying at 110 ° C. for one day, air was circulated and heat treatment was performed at 500 ° C. for 4 hours. The X-ray diffraction pattern of this product shows that the lattice constant is 24.56Å to 24.37Å compared with NaY type zeolite which is the starting material.
The Y-type crystallinity was not impaired, though the size was reduced and the unit cell was slightly shrunk. Further, the molar ratio of silica to alumina of this zeolite was increased from 5.6 to 24.8 as compared with the starting NaY-type zeolite (HY-1 zeolite).

(b) The above-mentioned HY zeolite was acid-treated with a 0.1N hydrochloric acid solution. Except this, the ion exchange conditions and the heat treatment conditions were the same as in the preparation of HY-1 zeolite. The molar ratio of silica to alumina of this zeolite was 7.0 (HY-2 zeolite).

(c) The above-mentioned HY zeolite was acid-treated at 25 ° C. with an aqueous acetic acid solution having a pH value of 2. Except this, the ion exchange conditions and the heat treatment conditions were the same as in the preparation of HY-1 zeolite. The molar ratio of silica to alumina of this zeolite was 11.5 (HY-3 zeolite).

(d) HY, HY-1, HY- obtained by the above operation
2 and 1 as alumina content in HY-3 zeolite
Alumina sol was added as a binder so as to be 5% by weight, and the mixture was molded into pellets. Then, it baked at 200 degreeC for 1 hour, and 500 degreeC for 10 hours under air circulation. The molded product was prepared to a particle size of 10 to 20 mesh and used for the reaction.

Example 2 and Comparative Example 1 5 g of HY-1 zeolite prepared in Example 1 was filled in a reaction bed of an atmospheric pressure fixed bed. After the catalyst layer was heated to 300 ° C., 50 g / Hr of a mixture of β-methylnaphthalene (refined product obtained by recrystallization) and decalin in a weight ratio of 1/1, 5.6 g / Hr of methanol and hydrogen / hydrogen were added. β-methylnaphthalene was supplied at 1.3 / 1 (molar ratio) (Example 2).

On the other hand, the HY zeolite prepared in Example 1 was used as a catalyst for reaction (Comparative Example 1).

The results are shown in the table, but the results of Example 2 showed a higher conversion rate of β-methylnaphthalene than that of Comparative Example 1. In addition, the formation of unusable 1,2-mono and / or dialkylnaphthalene in the isomer mixture of mono and / or dialkylnaphthalene was suppressed. Furthermore, the increase of 1,2-mono and / or dialkylnaphthalene with time was also suppressed.

Examples 3 and 4 In Examples 3 and 4, HY-2 zeolite and HY-3 zeolite prepared in Example 1 were used as catalysts, respectively. Other than this, the reaction was carried out under the same conditions as in Example 2. Both results show a high conversion of β-methylnaphthalene, the production of unusable 1,2-dimethylnaphthalene in the mixture of mono- and / or dialkylnaphthalene isomers is suppressed, and the increase over time is also suppressed. This is a significant improvement over Example 1.

Comparative Example 2 ZSM-5 zeolite having a silica / alna molar ratio of 50 was synthesized according to the method disclosed in U.S. Pat. No. 3,766,093, and after being converted to H type, an alumina sol having an alumina content of 15% by weight was prepared. Was added to obtain a molded product. The reaction was carried out under the same conditions as in Example 2, but the activity was not deteriorated, but the conversion rate was remarkably low.

Comparative Example 3 The reaction was performed under the same conditions as in Example 2 except that H-type mordenite (TSZ-640HOE manufactured by Toyo Soda) was used. Although the conversion was relatively high in the early stage of the reaction, the active life was remarkably short.

Claims (8)

[Claims] 1. A mono- and / or mono-characterized by reacting a naphthalene and / or an alkyl naphthalene with an alkylating agent in the presence of a dealuminaized phosphite type zeolite and a saturated alicyclic hydrocarbon compound. Method for producing dialkylnaphthalene. 2. The method according to claim 1, wherein the phosjasite type zeolite is a Y type zeolite. 3. The silica-to-alumina molar ratio of the dealuminaized faujasite-type zeolite is 6.5.
Claim (1) or (2) in the range of to 150
Method described in section. 4. The use of a zeolite that has been dealuminated by an inorganic acid or an organic acid, as claimed in any one of claims (1) to (3).
The method according to any one of paragraphs. 5. The alkylating agent has the general formula C _n H _{2n + 1} OH (n = 1 to
Alcohols represented by 4) and the general formula (C _n H _{2n + 1} ) ₂ O (n = 1
The method according to claim (1), wherein the method is at least one selected from ethers represented by (4) to (4). 6. A supply amount of a saturated alicyclic hydrocarbon compound is 0.2 to naphthalene and / or alkylnaphthalene.
A method according to claim (1) in the range of 10 weight ratio. 7. The method according to claim 1, wherein the alkylnaphthalene is methylnaphthalene. 8. The method according to claim 7, wherein the methylnaphthalene is β-methylnaphthalene.