JPH03251545A - Production of 2,6-dimethylnaphthalene - Google Patents

Abstract

PURPOSE:To obtain the subject highly pure compound by subjecting 2- methyl-1-(p-tolyl)-butene, etc., to a cyclic dehydrogenation reaction in the presence of a catalyst comprising the oxides of In and Al or a catalyst comprising the oxide of In and Al and the oxide of an alkali (earth) metal and/or the oxide of iron, tin, etc. CONSTITUTION:When 2-methyl-1-(p-tolyl)-butene, 2-methyl-1-(p-tolyl)-butene or a mixture thereof is subjected to a cyclic dehydration reaction, the oxides of In and Al are employed as a base catalyst component to prepare the highly pure substance having a high isomer purity. The catalyst includes (A) the oxides of In and Al, (B) the component A and the oxide of an alkali (earth) metal, (C) the component A and the oxide of iron, tin, Cr, Zn, etc., or (D) the component B and the oxide of iron, tin, Cr, Zn, etc. The subject is employed for preparing 2,6-naphthalene dicarboxylic acid which is a raw material for a high performance polyester.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a catalyst for producing 2,6-dimethylnaphthalene, which is useful as a raw material for 2,6-naphthalene dicarboxylic acid.

2.6-Naphthalene dicarboxylic acid has industrially important uses as a raw material for high-performance polyester used in the production of polyethylene naphthalate fibers, films, etc., which have excellent tensile strength and heat resistance.

[Prior art]

2,6-dimethylnaphthalene is a raw material for 2,6-naphthalene dicarboxylic acid, and needs to be able to be produced in large quantities and at low cost. In addition, since 2,6-naphthalene dicarboxylic acid, which is a raw material for high-performance polyester, is required to be highly isomerically pure, the raw material, 2,6-dimethylnaphthalene, must also be isomerically pure. is necessary. That is, dimethylnaphthalene has a 1,2-11 structure outside the 2,6 monolithic plate due to the position of the two methyl groups.
,3-11,4-11,5-11゜6-11,7-11
, 8-22.3-12.7-, and there are 9 isomers of 2.6 that are substantially free of isomers outside of these 2,6 integral plates.
- There is a need to produce dimethylnaphthalene in large quantities and at low cost.

2,6-Dimethylnaphthalene has conventionally been obtained by separating it from a tar fraction. However, when targeting a tar fraction, it is small in quantity and contains a large amount of isomer mixtures, so it is not easy to separate and purify it.

Therefore, it is difficult to industrially supply 2,6-dimethylnaphthalene in large quantities and at low cost by separating 2.6-dimethylnaphthalene from the tar fraction.

In recent years, methods for producing 2,6-dimethylnaphthalene from various raw materials have been proposed. However, an industrial production method that can efficiently and selectively synthesize 2,6-dimethylnaphthalene using inexpensive starting materials that can be obtained in large quantities has not yet been established.

For example, JP-A-49-18856 discloses a method for producing 2,6-dimethyltetralin by dehydrogenation.

For this method, it is difficult to obtain the raw material dimethyltetralin. That is, when separating from the tar fraction, the amount is small, and in the method of producing dimethyltetralin by cyclization of alkyl or alkenylbenzenes, the yield of dimethyltetralin is insufficient. Since isomers are also produced, isomerization and separation and purification from the isomer mixture are necessary to obtain the desired 2,6-unit.

Further, JP-A-63-112527 discloses a production method by methylating naphthalene or methylnaphthalene. Even with this production method, it is difficult to selectively obtain 2,6 monomers, and an isomerization reaction and separation and purification from the isomer mixture are required. Furthermore, both naphthalene and methylnaphthalene have quantitative limitations and are expensive as industrial raw materials.

Special Publication No. 50-17983, Special Publication No. 5047984, and Special Publication No. 50-17985. No. 5-(o-)lyl)pentene-2 is used as a raw material, and 2, which is produced by dehydrogenation cyclization.
A method for producing 6-dimethylnaphthalene is shown. This 5-(o-)lyl)pentene-2 is generally synthesized from 0-xylene and 1,3-phtadiene, but the synthesis of 5-(o-)lyl)pentene-2 by side chain alkylation is itself is not easy. That is, according to the example of Japanese Patent Publication No. 50-17985, in the dehydrocyclization of 5-(o-tolyl)pentene-2, 1,5-11.6 outside the 2,6 monolithic plate is
The formation of monoliths is remarkable, and in order to obtain 2,6 monoliths, 1,5-
11,6 integral isomerization and separation and purification of the isomer mixture are required.

Furthermore, as a method for producing 2,6-dimethylnaphthalene by cyclodehydrogenation of 2-methyl-1-(p-1lyl)-butene, Japanese Patent Publication No. 53-5292 describes a method for producing 2,6-dimethylnaphthalene by cyclodehydrogenation of 2-methyl-1-(p-1lyl)-butene. A method using a catalyst consisting of an alkaline earth metal oxide and alumina is shown, and Japanese Patent Publication No. 51-1701 shows a method using a chromia-alumina catalyst containing an alkali metal oxide. . However, all of these catalysts have low yields of 2,6-dimethylnaphthalene, and the isomer purity of the produced 2,6-dimethylnaphthalene is insufficient.

As described above, in the method of the prior art, isomerically high-purity 2,6-
It is difficult to produce dimethylnaphthalene inexpensively and in large quantities.

[Problem to be solved by the invention]

An alternative to these conventional techniques is to start with the extremely versatile raw materials of toluene, butene, and -carbon oxide, and to convert 2
, 6-dimethylnaphthalene was discovered,
A patent application has been filed (Patent application No. 63-239762)
issue).

That is, this method converts toluene, butene, carbon oxide to p
-) lylu sec butyl ketone is prepared, its carbonyl group is hydrogenated to give the corresponding alcohol, and this alcohol is dehydrated to give 2-methyl-1-(p-tolyl)-butene, 2-methyl-1-( This is a method for producing 2,6-dimethylnaphthalene by cyclodehydrogenating p-tolyl)-butene.

This method consists of four steps: acylation → hydrogenation → dehydration → cyclodehydrogenation.
Each step of acylation, hydrogenation, and dehydration proceeds with high yield and high selectivity, producing isomerically pure 2
-Methyl-1-(p-tolyl)-butene is obtained in high yield. However, the final step of cyclodehydrogenation using a chromia-alumina catalyst containing an alkali metal oxide was not sufficient in terms of yield of 2,6-dimethylnaphthalene, and improvements in this process were desired. .

[Means to solve the problem]

The present inventors have conducted intensive studies on a method for obtaining isomerically pure 2,6-dimethylnaphthalene in high yield from 2-methyl-1-(p4lyl)-butene, etc., and have found that indium and The present invention has been achieved based on the discovery that isomerically pure 2,6-dimethylnaphthalene can be obtained in high yield by using a catalyst based on an oxide of aluminum.

That is, the present invention cyclodehydrogenates 2-methyl-1-(p-tolyl)-butene, 2-methyl-1-(p-tolyl)-butane, or a mixture thereof to form 2,6-dimethyl When producing naphthalene, (a) a catalyst consisting of an oxide of indium and aluminum, (b) a catalyst consisting of an oxide of indium and aluminum and one or more oxides selected from alkali metals and alkaline earth metals, (c) A catalyst consisting of an oxide of indium and aluminum and one or more oxides selected from iron, tin, antimony, chromium, zinc, vanadium, nickel, and cobalt, or (
d) oxides of indium and aluminum and iron, tin,
2, 6 characterized by using a catalyst consisting of one or more oxides selected from antimony, chromium, zinc, vanadium, nickel, and cobalt and one or more oxides selected from alkali metals and alkaline earth metals. - A method for producing dimethylnaphthalene.

The present invention produces 2-methyl-1-(p-tolyl) by using a mixed catalyst of indium and aluminum oxides.
-Achieved by discovering that the production of 2,6-dimethylnaphthalene through cyclodehydrogenation of butene, etc. was dramatically improved, and isomerization reactions other than the 2,6-isomer were almost completely suppressed. It is something that was given.

That is, when aluminum oxide is used alone as a catalyst, a part of 2-methyl-1-(p-)lyl)-butene is converted to dimethylnaphthalene by cyclodehydrogenation, but significant isomerization is not observed. Reactions other than the intended purpose, such as oxidation, polymerization, and decomposition, are predominant. When indium oxide is used alone as a catalyst, 2-methyl-1-(p-)lyl)-
Almost no cyclodehydrogenation of butene occurs. On the other hand, when the mixed catalyst of indium and aluminum oxides of the present invention is used, there is almost no isomerization reaction outside the 2.6 integral plate, and the production of 2,6-dimethylnaphthalene is significantly improved.

That is, the oxides of aluminum and indium, which cannot be used alone as catalysts for producing 2,6-dimethylnaphthalene, become excellent catalysts for producing 2,6-dimethylnaphthalene by mixing them together. In addition, 2-methyl-
Chromia-alumina catalysts, which are said to be effective for the cyclodehydrogenation of 1-(p-tolyl)-butene, or catalysts containing alkali metals exhibit poor reaction performance in the coexistence of water; The catalyst of the invention shows no deterioration in reaction performance even in the coexistence of water.

Thus, for example, toluene, butene, -carbon oxide to p-
) 2-methyl-1(p-tolyl) obtained by producing lylu-sec butyl ketone, hydrogenating its carbonyl group to form the corresponding alcohol, and dehydrating this alcohol.
- When using butene as a raw material, when using a chromia-alumina catalyst or a catalyst containing an alkali metal, it is necessary to perform cyclodehydrogenation after removing water from the dehydration reaction product. When using the catalyst of the present invention, the dehydration reaction product can be used as it is as a raw material for cyclization dehydrogenation.

The ratio of indium to aluminum in the catalyst of the present invention is 0.005 indium per 1 atom of aluminum.
~0.5 atoms, preferably 0.01-063 atoms.

The method for preparing this catalyst is not particularly limited as long as it allows indium and aluminum to be uniformly dispersed on the surface of the catalyst participating in the reaction.

For example, alumina is impregnated with an indium compound, dried and
A method in which oxide precursors of aluminum and indium are separately prepared as precipitates, then mixed, dried and fired; A method in which oxide precursors of aluminum and indium are prepared as a co-precipitate, dried and fired; There is a method of mixing an oxide precursor or indium oxide and alumina sol, followed by drying and firing.

When impregnating alumina with an indium compound or preparing an oxide precursor of indium as a precipitate,
As the indium compound, an indium compound that dissolves in a suitable organic solvent such as water or methanol is used, and indium nitrate, indium sulfate, etc. can be suitably used. When preparing an aluminum oxide precursor as a precipitate, a compound soluble in an appropriate organic solvent such as water or methanol is used as the aluminum compound, and aluminum nitrate, sodium aluminate, aluminum sulfate, aluminum chloride, etc. are preferable. Can be used for

The catalyst consisting of oxides of aluminum and indium thus prepared was itself 2-methyl-1-(p
Shows excellent activity in the cyclodehydrogenation of -tolyl)-butene.

A catalyst consisting of oxides of aluminum and indium, to which at least one metal oxide selected from alkali metals and alkaline earth metal oxides is added, or iron, tin, antimony, chromium, zinc, vanadium, A catalyst containing one or more metal oxides selected from nickel and cobalt,
Alternatively, a catalyst in which at least one metal oxide selected from alkali metal and alkaline earth metal oxides is further added has further improved activity and selectivity.

These alkali metals, alkaline earth metals, iron, tin,
The amount of antimony, chromium, zinc, vanadium, nickel, and cobalt added is 0.1 to 1 atom of indium.
The number is 10 atoms, preferably 0.5 to 5 atoms. The method of adding these metal oxides is not particularly limited as long as each component is uniformly dispersed on the catalyst surface. For example, a method of impregnating a prepared catalyst consisting of oxides of aluminum and indium with a solution of these metal salts, a method of kneading, a method of adding these metal salt solutions simultaneously when making oxides of aluminum and indium, a method of adding these metal salt solutions at the same time when making oxides of aluminum and indium, Various methods can be used, such as a method in which oxide precursors of these metals are prepared in advance and mixed with alumina sol.

The catalyst precursor mixture thus prepared is dried at a temperature above room temperature, preferably from 70 to 130 °C, and
After baking at 00~800°C, mold if necessary.
Used as a catalyst in the present invention.

When producing 2,6-dimethylnaphthalene by cyclodehydrogenation of 2-methyl-1-(p-tolyl)-butene using the catalyst of the present invention, the reaction pressure is reduced, normal pressure, or elevated pressure. Any pressure is fine, but in practice, normal pressure to 2Kg/cm2
is preferred. The reaction temperature is 350-700°C, preferably 450-650°C. In addition, 2-methyl-1-(
When p-)lyl)-butane is used as a raw material, the reactivity is somewhat lower than when cyclodehydrogenating 2-methyl-1-(p-)lyl)-butene, and it is necessary to raise the reaction temperature. It is necessary to lower S■. The target product, 2,6-dimethylnaphthalene, is a solid with a melting point of 106°C, and the raw material, 2-methyl-1-(p-)lyl), is required for reaction operation and for suppressing side reactions such as polymerization. -Butene is preferably dissolved or diluted in toluene, benzene, steam, etc. and subjected to the reaction.

[Effects of the Invention] The method of the present invention uses extremely versatile raw materials such as toluene, butene, and carbon oxide as starting materials.

Further, in the method of the present invention, in the method of producing 2,6-dimethylnaphthalene via p-tolyl-5ec butyl ketone, there is almost no isomer other than the 2.6 monolithic plate, and a significantly high yield can be obtained.

Therefore, according to the present invention, it has become possible to produce high-purity 2,6-dimethylnaphthalene at low cost and in large quantities from extremely general-purpose raw materials such as toluene, butene, and carbon oxide, and the industrial significance of the present invention is is extremely large.

[Example] The present invention will be specifically described below with reference to Examples. However, the present invention is not limited to these Examples. The catalysts prepared according to each of the Examples and Comparative Examples were packed into a quartz reaction tube and treated with a toluene solution of 2-methyl-1-(p-)lyl)-butene or 2-methyl-1-butene under normal pressure.
A reaction was carried out using a toluene solution of (p-tolyl)-butane as a raw material, and the activity was confirmed.

Table 1 shows the results of each example and comparative example.

Example 1 32 g of indium nitrate (trihydrate) was mixed with 400 g of ion-exchanged water.
ml, add 200g of alumina, and stir under stirring for 4 hours.
After being impregnated at 5°C for 2 hours, it was dried under reduced pressure at 70'C and calcined in air at 550°C to prepare an indium oxide/aluminum oxide catalyst.

Add 60 g of indium nitrate (trihydrate) and 310 g of aluminum nitrate (9 hydrate) to 2j2 of pure water, dissolve, and keep at 40°C. Separately, add 170g of sodium carbonate to 21
Dissolve in pure water and keep at 40°C. Mix both solutions while maintaining the temperature of the contents at 40-45 °C under stirring,
The temperature was raised to 8°C. The generated precipitate was filtered, washed with pure water, dried at 110"C, and then heated at 550"C in air.
An indium oxide/aluminum oxide catalyst was prepared.

Example 3 Indium sulfate (nase hydrate) 50g was mixed with o, 4! 25g of sodium carbonate is dissolved in 0.41% pure water and kept at 40°C.

While stirring and keeping the temperature of the contents at 40-45°C,
Both solutions were mixed and heated to 80°C. The generated precipitate was filtered and washed with pure water to obtain a precipitate of an indium oxide precursor. The indium concentration in the precipitate was 27-tχ. 60 g of this precipitate and 650 g of alumina sol (alumina content: 10-1.chi.) were mixed, dried at 110.degree. C., and then calcined in air at 550.degree. C. to prepare an indium oxide/aluminum oxide catalyst.

2. 50g of the catalyst prepared in Example 1 was added to an aqueous solution of antimonylpotassium tartrate (antimonylpotassium tartrate concentration: 50g).
wtχ) and impregnated with stirring at 45°C for 2 hours, dried under reduced pressure at 70°C, and calcined in air at 550°C to form indium oxide, antimony oxide, potassium oxide,
An aluminum oxide catalyst was prepared.

50 g of the catalyst prepared in Example 1 was added to 160 g of an aqueous solution of stannous sulfate (concentration of stannous sulfate 5 wtχ), and the mixture was impregnated with stirring at 45°C for 2 hours, and then dried under reduced pressure at 70°C. death,
An indium oxide/tin oxide/aluminum oxide catalyst was prepared by firing in air at 550'C.

Yudan Shishi nickel nitrate (hexahydrate) 65g and indium nitrate 160g
Add g to pure water of 21 to dissolve and keep at 40°C. Separately, add 100g of sodium carbonate! Dissolve in pure water,
Maintain temperature of contents at 0″C, under stirring, 40-45°C
Both solutions were mixed while maintaining the temperature at 80°C.

The generated precipitate was filtered and washed with pure water to obtain a coprecipitate of indium and nickel oxide precursors. The indium concentration in the coprecipitation was 16-tχ, and the nickel concentration was 4.1w.
It was tχ. 120 g of this coprecipitate and 1800 g of alumina sol (alumina content 10-tχ) were mixed,
After drying at 0°C, it was calcined in air at 550°C to prepare an indium oxide/nickel oxide/aluminum oxide catalyst.

A calculated amount of indium oxide/aluminum oxide catalyst prepared in the same manner as in Example 1 was added to a calculated amount of nitrate aqueous solution of various metals in one boat.
The mixture was dried under reduced pressure at 50°C and calcined in air at 550"C to prepare a metal oxide/indium oxide/aluminum oxide catalyst.

Su Jli-Duji 13 A calculated amount of indium oxide/aluminum oxide catalyst prepared in the same manner as in Example 3 was added to a calculated amount of nitrate aqueous solution of various metals, and after impregnation at 45°C for 2 hours with stirring, the mixture was heated to 70°C.
The mixture was dried under reduced pressure and calcined in air at 550''C to prepare a metal oxide/indium oxide/aluminum oxide catalyst.

Comparison of soil chromium nitrate (9 hydrate) 169g and potassium nitrate 28.
Dissolve 4g in 400ml of ion-exchanged water, add 20ml to this
0 g of alumina was added and impregnated for 2 hours at 45°C with stirring, dried under reduced pressure at 7°C, calcined at 550"C in air,
Potassium oxide, chromium oxide, and aluminum oxide catalysts were prepared.

Comparative example 2 The alumina used in Example 1 was used as a catalyst.

Claims (1)

[Claims] In producing 2,6-dimethylnaphthalene by cyclodehydrogenation of 2-methyl-1-(p-tolyl)-butene, 2-methyl-1-(p-tolyl)-butane, or a mixture thereof. , (a) a catalyst consisting of an oxide of indium and aluminum, (b) a catalyst consisting of an oxide of indium and aluminum and one or more oxides selected from alkali metals and alkaline earth metals, (c) a catalyst consisting of indium and A catalyst consisting of an oxide of aluminum and one or more oxides selected from iron, tin, antimony, chromium, zinc, vanadium, nickel, and cobalt, or (d) an oxide of indium and aluminum, and iron, tin, antimony,
2,6-dimethyl characterized by using a catalyst consisting of one or more oxides selected from chromium, zinc, vanadium, nickel, and cobalt and one or more oxides selected from alkali metals and alkaline earth metals. Method for manufacturing naphthalene