JPH06279325A - Production of beta,beta'-dialkylnaphthalene - Google Patents

Abstract

PURPOSE:To provide a method for producing a beta,beta'-dialkylnaphthalene so designed that said compound can be obtained continuously in a high yield and in high selectivity without requiring particular after-treatment for the reaction along with easy regeneration of the catalyst. CONSTITUTION:The objective beta,beta'-dialkylnaphthalene can be obtained selectively by trans-alkylation of a beta-alkylnaphthalene with an alkyl-substituted aromatic compound in the presence of zeolite having fine pores of 12-membered oxygen ring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transalkylating β-alkylnaphthalene to produce β, β'-dialkylnaphthalene useful as an intermediate raw material for highly functional polyesters and the like.

[0002]

2. Description of the Related Art Among dialkylnaphthalenes, 2,6- and 2,7-dialkylnaphthalenes having an alkyl group at the β, β'-position of naphthalene can be obtained by oxidizing an alkyl group at the side chain thereof. 2,6-naphthalenedicarboxylic acid and 6-hydroxy-, which are raw materials for highly functional polyesters
Recently, it has attracted attention because it can produce 2-naphthoic acid and the like.

Conventionally, as a method for producing such dialkylnaphthalene, there is a method of separating and refining from cracked gas oil or tar oil. However, this method has a problem that separation and purification are difficult because the content rate of the compound in the feedstock is low and the distribution of the compound contained is wide.

There are also some known methods for producing dialkylnaphthalene by alkylating naphthalene and methylnaphthalene with a lower olefin. An example is the Friedel-Crafts reaction in which alkylation is carried out in a homogeneous liquid phase reaction using a catalyst such as aluminum chloride. However, in this reaction, the position of the alkyl group introduced into the naphthalene ring is non-selective and only gives many isomers as a mixture. Furthermore, reactions using solid catalysts such as silica-alumina, zeolite, solid superacids, and heteropolyacids have also been proposed, but all of these methods have regioselectivity of products or alkyl groups on the naphthalene ring as reaction by-products. However, there is a problem that a large amount of high-boiling compounds in which three or more are introduced are produced.

On the other hand, there are some known methods for producing dialkylnaphthalene by transalkylating naphthalene and methylnaphthalene with a transalkylating agent such as alkylbenzene. For example, β
-Methylnaphthalene is transisopropylated with a transisopropylating agent such as paradiisopropylbenzene in the presence of an aluminum chloride-nitromethane complex catalyst (Japanese Patent Publication No. 10585/1975), a method of washing with water to remove the catalyst after the reaction, A neutralization step is required, a large amount of wastewater is generated at this time, and the wastewater must be treated, which makes it difficult to reuse the catalyst. Furthermore, a method of trans-isopropylating β-methylnaphthalene with paracymene in the presence of a solid superacid catalyst (JP-A-1-
No. 299237), the type of transalkylating agent greatly affects the regioselectivity of the reaction, and it cannot be said to be a sufficient method.

[0006]

The present invention has been made to solve the above problems, and the object of the present invention is β-
Β, β 'from alkylnaphthalene with high yield and high selectivity
-To provide a method for producing a dialkylnaphthalene.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a β-alkylnaphthalene, particularly preferably β-methylnaphthalene, in the presence of a zeolite having pores of oxygen 12-membered ring, an alkyl-substituted aromatic compound, preferably A method for producing β, β'-dialkylnaphthalene, which comprises transalkylation with an alkylnaphthalene.

Examples of β-alkylnaphthalene which is a starting material for the above reaction include β-methylnaphthalene, β-ethylnaphthalene, β-isopropylnaphthalene and the like. These can be used alone or in a mixture.

On the other hand, as alkyl-substituted aromatic compounds which are transalkylating agents, cumene, ethylbenzene, cymene, ethyltoluene, diisopropylbenzene, triisopropylbenzene, triethylbenzene,
Tetraethylbenzene, hexamethylbenzene, isopropylnaphthalene, diisopropylnaphthalene, diethylnaphthalene, methyldiisopropylnaphthalene, dimethyldiisopropylnaphthalene, methyltriisopropylnaphthalene, dimethyltriisopropylnaphthalene,
Methyl diethyl naphthalene, dimethyl diethyl naphthalene, triethyl naphthalene, octamethyl naphthalene, etc. can be mentioned. These compounds can be used alone or as a mixture. These transalkylating agents are usually used in an amount of 0.1 to 30 per mol of β-alkylnaphthalene or a mixture thereof.
Used in the molar range.

The transalkylation reaction of the present invention can be carried out without a solvent or in the presence of a solvent. The solvent is
Any substance can be used as long as it does not adversely affect the reaction, and for example, nitrobenzene, o-dichlorobenzene, chlorobenzene, n-decane and the like can be used.

As a catalyst for the transalkylation reaction, zeolite having a pore structure of oxygen 12-membered ring is used. Specifically, Y-type zeolite, X-type zeolite, β
Type zeolite, Ω type zeolite, L type zeolite, mordenite and the like. The zeolite having a pore structure of oxygen 12-membered ring has pores having a size of about 0.6 to 0.8 nm. Zeolites with a small pore size of 0.6 nm or less have low transmethylation activity because it is difficult to incorporate the reaction product into the pores, and larger zeolites with a pore size of 0.8 nm or more have regioselectivity of the product. There is a problem that becomes low. These zeolites having a pore structure of oxygen 12-membered ring are usually used after being exchanged with hydrogen ions, but rare earth elements such as cerium and lanthanum, alkaline earth metal elements such as calcium and magnesium, boron,
It may be modified with gallium, phosphorus, zinc or the like. The outer surface of the zeolite may be coated with silicon or phosphorus or may be poisoned with an organic amine compound.
Further, these zeolites may be subjected to halogen treatment such as fluorine, steaming treatment, or acid treatment before use.

These zeolites having a pore structure of oxygen 12-membered ring can be used alone, as a mixture, or as a mixture with a binder. These catalysts are usually used in an amount of 0.01 to 500 parts by weight, preferably 0.1 to 100 parts by weight of β-alkylnaphthalene or a mixture thereof.
It is used in the range of 1 to 100 parts by weight.

The reaction temperature may be appropriately selected within a temperature range of usually 50 to 700 ° C., particularly preferably 100 to 100 ° C.
It is in the range of 500 ° C.

The reaction can be carried out in a flow system or a batch system. The reaction pressure is preferably atmospheric pressure to 100 kg / cm ² .

After completion of the reaction, β, β'-dialkylnaphthalene can be separated and recovered by a known means such as distillation or adsorption.

[0016]

INDUSTRIAL APPLICABILITY According to the method of the present invention, β, β'-dialkylnaphthalene can be obtained from an easily available compound in a high yield and with high selectivity, and further, no special reaction post-treatment is required. In addition, the catalyst can be easily regenerated and the reaction can be continuously performed.

[0017]

【Example】

(Example 1) 2.84 g (20 mmol) of β-methylnaphthalene
To this, 10.44 g of a mixture of dimethyldiisopropylnaphthalene and dimethyltriisopropylnaphthalene (average molecular weight = 261, 40 mmol) was added, and a USY-type zeolite (manufactured by Tosoh Corporation, HSZ-350HU) was added as a catalyst.
A) 1.0 g was added and reacted at 160 ° C. for 2 hours. After completion of the reaction, the reaction product was analyzed by gas chromatography to find that the conversion rate of β-methylnaphthalene was 90%,
The yield of methylisopropylnaphthalene was 64%, the proportion of 2-methyl-6-isopropylnaphthalene in methylisopropylnaphthalene was 44%, and the proportion of 2-methyl-7-isopropylnaphthalene was 44%. Further, as a result of separating methyl isopropylnaphthalene from this reaction product by distillation, 90% pure β, β′-dialkylnaphthalene was obtained.

(Example 2) H-mordenite as a catalyst
(Tosoh Corporation, HSZ-630HOA) 2.0 g was used, and the reaction was carried out under the same conditions as in Example 1 except that the reaction temperature was 240 ° C. After completion of the reaction, the reaction product was analyzed by gas chromatography to find that the conversion rate of β-methylnaphthalene was 70%, the yield of methylisopropylnaphthalene was 53%, and the yield of methylisopropylnaphthalene was 2-.
The ratio of methyl-6-isopropylnaphthalene is 47%, 2
The proportion of -methyl-7-isopropylnaphthalene was 35%.

(Example 3) 1.0 g of H-β type zeolite (CP811BL-25 manufactured by PQ Zeolite Co., Ltd.) as a catalyst
Was used under the same conditions as in Example 1 except that the reaction temperature was 220 ° C. and the reaction time was 1 hour. After completion of the reaction, the reaction product was analyzed by gas chromatography to find that the conversion rate of β-methylnaphthalene was 76%, the yield of methylisopropylnaphthalene was 48%, and 2-methyl-6-isopropylnaphthalene occupied in methylisopropylnaphthalene. Was 45%, and the ratio of 2-methyl-7-isopropylnaphthalene was 41%.

Example 4 The reaction was carried out under the same conditions as in Example 1 except that the transalkylating agent was 6.40 g (40 mmol) of paradiisopropylbenzene. After the reaction was completed, the reaction product was analyzed by gas chromatography.
The conversion rate of β-methylnaphthalene is 67%, the yield of methylisopropylnaphthalene is 58%, the ratio of 2-methyl-6-isopropylnaphthalene in methylisopropylnaphthalene is 46%, and the ratio of 2-methyl-7-isopropylnaphthalene. Was 43%.

(Comparative Example 1) Silica alumina as a catalyst
The reaction was carried out under the same conditions as in Example 1 except that 1.0 g of N-631 (L) manufactured by JGC Chemical Co., Ltd. was used. After the reaction was completed, the reaction product was analyzed by gas chromatography to find that β
-The conversion of methylnaphthalene is 22%, the yield of methylisopropylnaphthalene is 18%, the proportion of 2-methyl-6-isopropylnaphthalene in methylisopropylnaphthalene is 12%, the proportion of 2-methyl-7-isopropylnaphthalene is It was 7%.

(Comparative Example 2) As a catalyst, 98% by weight of sulfuric acid was sprinkled on a dried product of zirconium hydroxide, and the acid strength H ₀ obtained by firing was in the range of -13.2 to -13.7. The reaction was carried out under the same conditions as in Example 1 except that 1.0 g of a certain solid superacid was used. After completion of the reaction, the reaction product was analyzed by gas chromatography to find that the conversion rate of β-methylnaphthalene was 64%, the yield of methylisopropylnaphthalene was 39%, which accounted for 2% of methylisopropylnaphthalene.
-Methyl-6-isopropylnaphthalene ratio is 21%,
The ratio of 2-methyl-7-isopropylnaphthalene is 13%
Met.

(Comparative Example 3) Cs _2.5 H _0.5 PW as a catalyst
_The reaction was carried out under the same conditions as in Example 1 except that 1.0 g of ₁₂ O ₄₀ was used. After completion of the reaction, the reaction product was analyzed by gas chromatography to find that the conversion rate of β-methylnaphthalene was 85%, the yield of methylisopropylnaphthalene was 38%, and 2-methyl-6-isopropylnaphthalene occupied in methylisopropylnaphthalene. The ratio of 24%, 2-
The proportion of methyl-7-isopropylnaphthalene was 20%.

Comparative Example 4 The reaction was carried out under the same conditions as in Example 1 except that 1.0 g of H-ZSM5 zeolite (Si / Al molar ratio = 22) was used as the catalyst and the reaction temperature was 240 ° C. After completion of the reaction, the reaction product was analyzed by gas chromatography to find that the conversion rate of β-methylnaphthalene was 3% and the yield of methylisopropylnaphthalene was 3%.
2-Methyl-6-occupying methyl isopropyl naphthalene
Isopropyl naphthalene ratio is 26%, 2-methyl-7
The proportion of isopropylnaphthalene was 19%.

Comparative Example 5 β-methylnaphthalene 20.0
g (141 mmol) and USY zeolite (Tosoh Corp., HS
Z-350HUA) 1.0g into a glass reaction vessel,
While circulating propylene at a rate of 200 ml / min, 1
The reaction was carried out at 80 ° C for 2 hours. After completion of the reaction, the reaction product was analyzed by gas chromatography to find that the conversion rate of β-methylnaphthalene was 84%, the yield of methylisopropylnaphthalene was 57%, and 2-methyl-6-isopropylnaphthalene occupied in methylisopropylnaphthalene. Was 32%, and the proportion of 2-methyl-7-isopropylnaphthalene was 29%.

Claims (3)

[Claims] 1. A method for producing β, β′-dialkylnaphthalene, which comprises transalkylating β-alkylnaphthalene with an alkyl-substituted aromatic compound in the presence of a zeolite having pores of 12-membered oxygen ring. . 2. The β, β ′ according to claim 1, wherein the β-alkylnaphthalene is β-methylnaphthalene.
-Method for producing dialkylnaphthalene. 3. The method for producing β, β′-dialkylnaphthalene according to claim 1, wherein the alkyl-substituted aromatic compound is an alkylnaphthalene.