JP2805107B2 - Method for producing 1,5-dialkylnaphthalene - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing 1,5-dialkylnaphthalene.

1,5-Dialkylnaphthalenes are themselves useful as polymer raw materials, and also, by isomerization,
It can be 2,6-dialkylnaphthalene which is useful as a polymer raw material.

Conventional technology Dehydrogenation reaction of 1,5-dimethyltetralin in the gas phase in the presence of a copper-chromium catalyst or a silica-alumina catalyst supporting platinum or palladium to produce 1,5-dimethylquinaphthalene This method is described in JP-B-52-47461 and JP-B-55-42052. However, 1,5-
Dimethyltetralin is very expensive to use as an industrial raw material.

On the other hand, by isomerization of dimethylnaphthalene, 1,5-
The fact that dimethylnaphthalene can be obtained is disclosed in
It is known from JP 60-38331 and JP-B 60-69043, but the yield is remarkably low.

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the production of 1,5-dialkylnaphthalene. -To provide a method for producing dialkylnaphthalene.

Means for Solving the Problems A method for producing a 1,5-dialkylnaphthalene according to the present invention is a method for producing a 1,5-dialkylnaphthalene represented by the general formula (R ¹ ) ₂ -Naph- (R ² ) ₂ (I) R ¹ each independently represents a methyl group or an ethyl group, and R ² each independently represents an isopropyl group, a sec-butyl group or a t-butyl group.) and characterized in that the radical R ² is dealkylated.

In the method of the present invention, the mixed alkylnaphthalene represented by the general formula (I) is used as a raw material. The mixed alkyl naphthalene, and a two alkyl radicals R ¹ and the two alkyl groups R ² in any position of the naphthalene ring. Here, the alkyl group R ¹ represents a methyl group or an ethyl group, and the two alkyl groups R ¹ may be the same or different. Alkyl group R ² is an isopropyl group, se
It indicates c- butyl or t- butyl group, also these two alkyl radicals R ^2, identical may, or may be different from one.

Such mixed alkylnaphthalenes can be prepared in the presence of a catalyst by isopropanol, propylene, isobutene, 2-
It can be obtained by alkylating dimethylnaphthalene, methylethylnaphthalene or diethylnaphthalene (hereinafter referred to as dialkylnaphthalenes) using butene or the like as an alkylating agent. Such alkylation reactions of dialkylnaphthalenes are already well known.

Examples of the catalyst used for the alkylation of dialkylnaphthalenes include complex oxides such as silica alumina, silica titania, silica magnesia, and silica borea, niobium oxide, zirconium oxide, titanium oxide, silica, alumina, tin oxide, and iron oxide. solid superacid was supported sulfate ion in the oxide etc., HF / BF _3, etc. of the liquid superacid, X-type zeolite, Y-type zeolite, stabilized Y type zeolite (US
Y), A-type zeolite, L-type zeolite, mordenite, proton or metal ion exchangers of zeolites such as ZSM-5, activated clay and the like.

Further, examples of the catalyst include protons and metal ions of layered compounds such as montmorillonite, bentonite, vermiculite, acid clay, tetrasilicic mica, hectorite, saponite, and teniolite, and polynuclear hydroxide ions such as aluminum, zirconium, iron, and chromium. Exchanger and the like can be mentioned. These ion exchangers may have a mixture of protons, metal ions and polynuclear hydroxyl ions as ions, or may be cross-linked with an oxide such as alumina or zirconia.

In addition to the above, MELS, sulfonated polyphenylsiloxane and its fluorine, trifluoromethyl group-substituted product, Amberlyst 15, ion exchange resins such as Nafion, aluminum chloride, aluminum bromide, boron trifluoride, chloride Gallium, iron chloride, titanium chloride, tin chloride, and catalysts in which these are supported on metal oxides, heteropolyacid-supported heteropolyacids, hydrogen fluoride, trifluoromethanesulfonic acid, boron trifluoride, sulfuric acid, fluorosulfuric acid, p -Toluenesulfonic acid, hydrochloric acid, phosphoric acid, aluminum phenoxide, aluminum alkoxide and the like.

The reaction can be performed in a liquid phase or a gas phase. In the case of a liquid phase reaction, the reaction temperature is usually −10 to 350 ° C., preferably 30 to 300 ° C., and in the case of a gas phase reaction, it is usually 100 to 500 ° C., preferably 200 to 400 ° C. Range.

For the reaction, a reaction solvent is used as necessary. As the reaction solvent, for example, hexane, heptane, octane, decane, hydrocarbons such as decalin, dichloromethane,
Halogenated hydrocarbons such as 1,2-dichloroethane, chlorobenzene and dichlorobenzene, ethers such as diethyl ether and tetrahydrofuran, and nitrated hydrocarbons such as nitrobenzene and nitromethane are preferably used.

For example, when the reaction is carried out in a liquid phase, the amount of the catalyst to be used is generally 0.1 to 200 parts by weight, preferably 1 to 80 parts by weight, per 100 parts by weight of dialkylnaphthalenes.

The alkylating agent is usually used in a molar amount of 1 to 6 times the amount of the raw material at the time of charging or feeding.

In the present invention, as the mixed alkylnaphthalene represented by the general formula (I), for example, dimethyldiisopropylnaphthalene, diethyldiisopropylnaphthalene, dimethyldi-sec-butylnaphthalene, dimethyldi-t-butylnaphthalene, diethyldi-sec-butylnaphthalene, Diethyl di-t-butyl naphthalene, methyl ethyl diisopropyl naphthalene and the like are preferably used.

Then, according to the invention, the mixed alkylnaphthalene is isomerized / transalkylated. By this isomerization / transalkylation, the mixed alkylnaphthalene becomes a thermodynamically stable mixed alkylnaphthalene. For example, dimethyldiisopropylnaphthalene mainly isomerizes to 1,5-dimethyl-3,7-diisopropylnaphthalene.

The isomerization / transalkylation of the mixed alkylnaphthalene is also performed in the presence of a catalyst. As the catalyst, the same acid catalyst as used in the production of the mixed alkylnaphthalene described above is used.
The same solvent as used in the production of the mixed alkylnaphthalene is used as necessary.

The reaction can be performed in a liquid phase or a gas phase. In the case of a liquid phase reaction, the reaction temperature is usually in the range of 30 to 350 ° C., preferably 50 to 300 ° C., and in the case of a gas phase reaction, it is usually 100 to 500 ° C., preferably 200 to 400 ° C. Range.

When the reaction is carried out in the liquid phase, for example, the amount of the catalyst to be used is generally 0.1 to 200 parts by weight, preferably 1 to 80 parts by weight, per 100 parts by weight of the mixed alkylnaphthalenes.

Mixed alkylnaphthalene isomerized as described above,
It is then dealkylated. When the R ² group is an isopropyl group, a sec-butyl group or a t-butyl group, the dealkylation of the mixed alkylnaphthalene can be carried out as an olefin such as propylene or butene, respectively. Also, by transalkylating these alkyl groups to a suitable aromatic compound, the mixed alkylnaphthalene can be dealkylated.

The dealkylation reaction of mixed alkylnaphthalene is also performed in the liquid phase,
It can be carried out in any of the gaseous phases, but is preferably carried out by a liquid phase reaction. In the case of such a liquid phase reaction, as a solvent, for example, hexane, heptane, octane, decane, hydrocarbons such as decalin, benzene, toluene, xylene, mesitylene, ethylbenzene, diethylbenzene, triethylbenzene, propylbenzene, isopropylbenzene, Unsubstituted or substituted aromatic hydrocarbons such as naphthalene, methylnaphthalene, dimethylnaphthalene and dibenzyl, phenols and derivatives thereof such as phenol, alkylphenol and alkoxyphenol, aromatic ethers such as anisole and diphenylether, hexyl alcohol, heptyl alcohol and octyl alcohol And higher aliphatic alcohols. Besides these, nitrated hydrocarbons such as sulfolane, nitrobenzene and nitromethane are also suitably used.

As the catalyst used for the dealkylation of the mixed alkylnaphthalene, the same catalyst as used in the above-described production of the mixed alkylnaphthalene and the isomerization thereof can be used. Among them, particularly, activated clay, or monrilonite, bentonite, vermiculite, acidic White clay, tetrasilicic mica, hectorite, saponite, protons of layered compounds such as teniolite, metal ions, aluminum,
Polynuclear hydroxyl ion exchangers such as zirconium, iron and chromium,
And crosslinked oxides thereof, such as alimina and zirconia,
Aluminum chloride, aluminum bromide, heteropolyacid supported heteropoly acid, sulfuric acid, trifluoromethanesulfonic acid, fluoro acids, phosphoric acid, p- toluenesulfonic acid, hydrochloric acid, liquid superacid such as HF / BF _3, aluminum phenoxide, aluminum alkoxides, MELS, sulfonated polyphenylsiloxane, and their fluorine, trifluoromethyl-substituted products, Amberlyst 15, and ion exchange resins such as Nafion are preferably used.

For example, when the reaction is carried out in the liquid phase, the amount of the catalyst to be used is generally 0.1 to 200 parts by weight, preferably 1 to 80 parts by weight, per 100 parts by weight of the mixed alkylnaphthalenes.

In the case of a liquid phase reaction, the reaction temperature is usually 30 to 350 ° C,
It is preferably in the range of 50 to 300 ° C, and in the case of a gas phase reaction, usually in the range of 100 to 500 ° C, preferably 200 to 400 ° C.

As described above, when dealkylating the R ² group of the mixed alkylnaphthalene as olefin, the reaction system is nitrogen,
Purging with an inert gas such as carbon dioxide, helium, or argon is effective for preventing a reverse reaction.

In the method of the present invention, the isomerization of the dialkylnaphthalenes may be carried out simultaneously with the alkylation of the dialkylnaphthalenes, and the isomerization of the mixed alkylnaphthalenes does not necessarily need to be carried out until the equilibrium composition is reached.

As described above, according to the method of the present invention, a mixed alkylnaphthalene isomerized to form a 1,5-dialkyl (R ¹ ) -3,7
Increasing the concentration of dialkyl (R ² ) naphthalene and dealkylating (R ² ) it to obtain 1,5-dialkyl naphthalene, which is difficult to obtain by a conventional method, in a subtle and high yield; Can be.

Thus, for example, dimethylnaphthalenes are alkylated to give dimethyldiisopropylnaphrenes, which are isomerized and thermodynamically stable 1,5-dimethyl-3,7-.
By isomerizing to diisopropylnaphthalene and dealkylating it, 1,5-dimethylnaphthalene can be obtained in good yield.

EXAMPLES Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1 A mixture of 40 g of a dimethylnaphthalene mixture containing 7% of 1,5-dimethylnaphthalene, 4.0 g of aluminum chloride and 200 ml of o-dichlorobenzene was heated to 40 ° C., and propylene was added to the phosphorus at a rate of 70 ml / min. For 7 hours.
Then, the mixture was heated to 100 ° C. and stirred for 2 hours.

After decomposing the catalyst, the reaction product was extracted with dichloromethane, and the solvent was distilled off to obtain 65 g of an oil.

As a result, the conversion of dimethylnaphthalene was 94%, and the selectivity of dimethyldiisopropylnaphthalene was 72%.

A mixture comprising 10 g of the dimethylisopropylnaphthalene mixture thus obtained, 3 g of montmorillonite substituted with aluminum ions and 50 ml of mesitylene was stirred at the mesitylene reflux temperature for 5 hours.

The reaction results showed a dimethylnaphthalene content of 73%, of which
The 1,5-dimethylnaphthalene content was 57%.

Example 2 5 g of the dimethyldiisopropylnaphthalene mixture obtained in Example 1, 1.5 g of aluminum chloride and 50 ml of mixed xylene
Was stirred at 50 ° C. for 3 hours.

The reaction result was dimethylnaphthalene content 70%, of which
The 1,5-dimethylnaphthalene content was 51%.

Comparative Example 1 A mixture consisting of 4 g of a dimethylnaphthalene mixture containing 7% of 1,5-dimethylnaphthalene, 0.4 g of aluminum chloride and 20 ml of o-dichlorobenzene was stirred at 100 ° C. for 2 hours.

The reaction results showed a dimethylnaphthalene content of 76%, of which
The 1,5-dimethylnaphthalene content was 4%.

Comparative Example 2 A mixture consisting of 4 g of a dimethylnaphthalene mixture containing 7% of 1,5-dimethylnaphthalene, 1.2 g of montmorillonite substituted with aluminum ion and 10 ml of n-decane was charged into an autoclave and stirred at 220 ° C. for 3 hours.

The reaction results showed a dimethylnaphthalene content of 81%, of which
The 1,5-dimethylnaphthalene content was 3%.

Example 4 A dimethylnaphthalene mixture containing 7% of 1,5-dimethylnaphthalene in 20 g of H ⁺ -USY (TSZ-330 manufactured by Tosoh Corporation) at a temperature of 350 ° C. and propylene 5 at a rate of 15 cm ³ / hour.
/ H for 2 hours to obtain 48 g of an oil.

As a result, the conversion of dimethylnaphthalene was 71%, and the selectivity of dimethyldiisopropylnaphthalene was 67%.

A mixture comprising 2 g of the dimethyldiisopropylnaphthalene mixture thus obtained, 0.5 g of the strong acidic ion exchange resin Nafion and 15 g of phenol was stirred at 140 ° C. for 2 hours.

The reaction results showed a dimethylnaphthalene content of 76%, of which
The 1,5-dimethylnaphthalene content was 41%.

Comparative Example 3 4 g of a dimethylnaphthalene mixture containing 7% of 1,5-dimethylnaphthalene was stirred at 170 ° C. for 3 hours with 1 g of Nafion and 20 g of phenol.

The reaction result was a dimethylnaphthalene content of 72%, of which
The 1,5-dimethylnaphthalene content was 4%.

Example 4 1,6-dimethylnaphthalene 4 g, aluminum chloride 1.0 g
And a mixture of 20 ml of o-dichlorobenzene was heated to 40 ° C., and 2-butene was passed into the mixture at a rate of 20 ml / min for 2.5 hours. Then, the mixture was heated to 100 ° C. and stirred for 2 hours.

After decomposing the catalyst, the reaction product was extracted with dichloromethane, and the solvent was distilled off to obtain 6.8 g of an oil.

The reaction result was 1,6-dimethylnaphthalene conversion 92%,
Dimethyldibutylnaphthalene selectivity was 76%.

A mixture comprising 1 g of the dimethyldibutylnaphthalene mixture thus obtained, 0.3 g of p-toluenesulfonic acid and 7 g of diphenylether was stirred at 140 ° C. for 3 hours.

The reaction results showed a dimethylnaphthalene content of 82%, of which
The 1,5-dimethylnaphthalene content was 62%.

Example 5 Dimethyldibutylnaphthalene mixture obtained in Example 4
A mixture consisting of 1 g, activated clay 0.5 g and diethylbenzene 5 ml was stirred at 150 ° C. for 2 hours.

The reaction results showed a dimethylnaphthalene content of 78%, of which
The 1,5-dimethylnaphthalene content was 55%.

Comparative Example 4 A mixture consisting of 1 g of 1,6-dimethylnaphthalene, 0.5 g of activated clay and 5 ml of diethylbenzene was stirred at 150 ° C. for 2 hours.

The reaction results showed a dimethylnaphthalene content of 96%, of which
The 1,5-dimethylnaphthalene content was 0.4%.

Example 6 A mixture of 30 g of a diethylnaphthalene mixture containing 8% of 1,5-diethylnaphthalene, 3.0 g of aluminum chloride and 180 ml of 1,2-dichloroethane was heated to 40 ° C., and propylene was added thereto at a rate of 60 ml / min. For 6 hours. Then, the mixture was heated to 50 ° C. and stirred for 2 hours.

After decomposing the catalyst, the reaction product was extracted with dichloromethane, and the solvent was distilled off to obtain 65 g of an oil.

As a result, the conversion of diethylnaphthalene was 86%, and the selectivity of diethyldiisopropylnaphthalene was 70%.

A mixture of 10 g of the thus obtained diethyldiisopropylnaphthalene mixture, tetrasilicic mica substituted with aluminum ions and 50 ml of mesitylene was stirred at the mesitylene reflux temperature for 4 hours.

The reaction result was a diethyl naphthalene content of 67%, of which
The 1,5-dimethylnaphthalene content was 56%.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C07C 6/12 C07C 6/12 // C07B 61/00 300 C07B 61/00 300

Claims (1)

(57) [Claims] 1. A compound represented by the general formula (R ¹ ) ₂ -Naph- (R ² ) ₂ wherein Naph represents a naphthalene ring, R ¹ each independently represents a methyl group or an ethyl group, and R ² represents each independently isopropyl group, sec- butyl represents a group or t- butyl group.) the mixture alkylnaphthalene represented by isomerization with and then it is characterized in that the alkyl radical R ² is dealkylated 1,5 dialkylnaphthalene Production method.