JP2002255866A - Method of producing exo-tetrahydrodicyclopentadiene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing exo-tetrahydrodicyclopentadiene (exo-THDC) by isomerization of endo-trahydro-dicyclopentadiene(endo-THDC) in the presence of an aluminum halide anhydride wherein the formation of by-products is suppressed in markedly shortened reaction time with industrial advantage. SOLUTION: When the exo-THDC is produced by isomerization of the endo- THDC in the presence of an aluminum halide anhydride catalyst, an aluminum halide hydrate is used together as a cocatalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing exo-tetrahydrodicyclopentadiene. More specifically, the present invention relates to an improvement in a method for isomerizing endo-tetrahydrodicyclo in the presence of anhydrous aluminum halide to produce a corresponding exo form.

[0002]

2. Description of the Related Art Exo-tetrahydrodicyclopentadiene (hereinafter also referred to as exo-THDC) has a boiling point of 1%.
It is a known substance with a colorless faint smell at 87 ° C (under normal pressure) and a melting point of -79 ° C. BACKGROUND ART Heretofore, there has been known a method of producing exo-THDC by isomerizing endo-tetrahydrodicyclopentadiene (hereinafter, also referred to as endo-THDC) in the presence of anhydrous aluminum halide.

For example, JP-A-50-13370 discloses that exo-THDC isomerized from endo-THDC in the presence of a Friedel-Crafts type catalyst such as anhydrous aluminum chloride and anhydrous aluminum bromide and an aromatic solvent. Are described. Further, it has been proposed that in this method, tertiary butyl chloride, isopropyl bromide or the like is used in combination as a cocatalyst to improve the catalytic activity. However, when the amount of the catalyst used is a raw material (End-T
HDC) is not more than 20% by weight, and the by-product (decalin) reaches as much as 4%.

US Pat. No. 4,086,284 discloses a method for synthesizing exo-THDC from endo-THDC in the presence of an anhydrous aluminum chloride catalyst in order to avoid the formation of by-products (decalin, adamantane, etc.) It has been proposed to use an inert solvent to control the reaction temperature to 90 ° C. or lower, preferably to about 70 ° C. However, the conversion of endo-THDC is low with this method and is not fully satisfactory.

[0005] Improvements in the isomerization reaction using anhydrous aluminum chloride as a catalyst as described above have also been reported. For example, Japanese Patent Application Laid-Open No. 57-32232 discloses a method for increasing the reaction temperature to 100 to 150 ° C. and directly contacting the endo-THDC with a sludge containing aluminum chloride to improve the conversion of the endo-THDC. It has been disclosed. However, such relatively high temperatures (10
(0 to 150 ° C.), by-products such as trans-decalin (boiling point at normal pressure; 185 ° C.) and adamantane generally tend to be easily produced. Since the boiling point of by-produced trans-decalin is very close to that of exo-THDC (normal pressure boiling point: 187 ° C.), there is a problem that separation is difficult by ordinary simple distillation.

As described above, in the conventional method for producing exo-THDC using an anhydrous aluminum halide catalyst, (1) when the reaction temperature is set to 100 ° C. or lower, the reaction time is low because the initial reaction activity of the catalyst is low. And (2) when the reaction temperature is set to 100 ° C. or higher, by-products are easily formed.

[0007]

Accordingly, the present invention provides an endo-THD in the presence of an anhydrous aluminum halide catalyst.
In a method for producing exo-THDC by isomerizing C, an object of the present invention is to provide a method for industrially advantageous production of exo-THDC in which the generation of by-products is suppressed and the reaction time is significantly reduced. And

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on high activation of an anhydrous aluminum halide catalyst in order to achieve the above object. It has been found that the initial reaction activity of is significantly increased, and that the reaction time can be significantly reduced even at a relatively low reaction temperature at which the generation of by-products can be suppressed, and the present invention has been completed.

Thus, according to the present invention, in a method for producing exo-THDC by isomerizing endo-THDC in the presence of an anhydrous aluminum halide catalyst, aluminum hydrate is used as a co-catalyst. Exo-THDC is provided.
The catalyst is preferably anhydrous aluminum chloride, and the cocatalyst is preferably aluminum chloride hexahydrate. The use amount of the cocatalyst is preferably 2 to 100% by weight based on the catalyst. Further, the reaction is preferably carried out in the presence of an inert solvent. The inert solvent is exo-THD
C and its usage is 5
It is preferably about 90% by weight.

The method of the present invention is capable of industrially producing exo-THDC by employing these constitutions.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the exo-THDC of the present invention will be described.
The production method of will be described in detail for each of the items of raw material, catalyst, cocatalyst, isomerization reaction, and target product.

Raw Material: Endo-THDC The raw material Endo-THDC of the present invention is a known substance having a boiling point of 193 ° C. (under normal pressure) and a melting point of 77 ° C. and having a colorless slight odor. The target exo-THDC described below has a stereoisomeric relationship.

The method for producing the raw material endo-THDC is not particularly limited, and a method obtained by a conventionally known production method may be used. Dicyclopentadiene (hereinafter, also referred to as DCP) having a purity of 95% by weight or more is used. It is preferable to use those obtained by hydrogenation. A more preferred DCP purity is 97% by weight or more.

[0014] Such DCP, for example, DCP obtained by the process and the remaining C ₅ fraction obtained by extracting isoprene from C ₅ fraction by-produced during pyrolysis of naphtha treating dimerization
A fraction having a relatively high content can be obtained by removing unreacted substances and by-products using a rectification apparatus generally used in industry and increasing the DCP content. Such high purity D
The impurities contained in the CP in trace amounts are, for example, vinyl norbornene, isopropenyl norbornene, propenyl norbornene, tricyclopentadiene and the like.

The method of hydrogenating the above-mentioned DCP to convert it into endo-THDC, which is a raw material of the present invention, is not particularly limited, and it may be hydrogenated according to a conventional method using a known hydrogenation catalyst such as a palladium catalyst. Since DCP usually exists in a thermally energy stable end body, THDC obtained by hydrogenation has an end structure. In this hydrogenation step, endo-THDC is not isomerized to exo-THDC. The purity of such endo-THDC is usually at least 90% by weight, preferably at least 92% by weight, more preferably at least 94% by weight.

Catalyst: anhydrous aluminum halide The catalyst used in the process of the present invention is anhydrous aluminum halide . Examples of the anhydrous aluminum halide include anhydrous aluminum chloride and anhydrous aluminum bromide, and anhydrous aluminum chloride is preferable. The catalyst is not particularly limited, and a commercially available catalyst may be used. For example, generally available industrial anhydrous aluminum chloride (powder) may be used as it is, or may be further pulverized if necessary. Regarding the method of using the catalyst, the catalyst may be added to the reaction system as it is, or may be added to the reaction system after being suspended in an inert solvent described later. The amount of the catalyst used is not particularly limited, but is usually 0.1 to 20% by weight, preferably 0.2 to 15% by weight, more preferably 0.5 to 10% by weight, based on the raw material of endo-THDC.

Cocatalyst : Aluminum halide hydrate In the present invention, it is essential to use aluminum halide hydrate as a cocatalyst. Here, the cocatalyst refers to a substance which has no catalytic activity by itself but is used together with a compound having catalytic activity to improve the catalytic activity. Examples of the aluminum halide hydrate include aluminum chloride hexahydrate, aluminum bromide hexahydrate, aluminum bromide dehydrate, aluminum iodide hexahydrate, and aluminum iodide dehydrate. And aluminum chloride hexahydrate is preferred. These cocatalysts are used alone or in combination of two or more.

The co-catalyst aluminum halide hydrate can itself convert endo-THDC to exo-THDC.
Does not have a catalytic function for isomerization. In addition, there is no activity as a general Friedel-Crafts catalyst. further,
It is known that even when an aluminum halide hydrate is heated, it does not become anhydrous aluminum halide but decomposes to aluminum oxide.

The amount of the cocatalyst used is not particularly limited, but is usually 2 to 100% by weight, preferably 3 to 100% by weight, based on the catalyst.
50% by weight. It is not economical to make the amount excessively large, and if it is made too small, the effect of the cocatalyst is not exhibited.

The manufacturing method of isomerization present invention, the presence of anhydrous aluminum halide catalyst described above, a process for the preparation of exo -THDC material end -THDC the isomerizing halogenated aluminum solution as cocatalyst It is characterized by using a Japanese product.

This isomerization reaction can be carried out either in the presence or absence of a reaction solvent. When a reaction solvent is used, it is preferable to use an inert solvent that does not affect the catalytic activity. Such inert solvents include, for example, aromatic hydrocarbons, linear (linear or branched) or cyclic aliphatic hydrocarbons, and the like.

Examples of the aromatic hydrocarbon include benzene, toluene, ethylbenzene, xylene, chlorobenzene, dichlorobenzene, nitrobenzene and the like. Examples of the chain aliphatic hydrocarbon include, for example, n
-Pentane, n-hexane, n-heptane, isohexane, isoheptane, n-octane, isooctane, n-
Decane, isodecane, n-undecane, n-dodecane,
n-tridecane and the like. Examples of the cyclic aliphatic hydrocarbon include cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, decalin, paramentane, bicyclohexyl, and the like.

In general, the use of an inert solvent having a boiling point close to that of the target exo-THDC causes a problem that the purification of the target product becomes complicated. It is preferably used in the present method without any hindrance.

The amount of the inert solvent to be used is not particularly limited, but is usually 2 to the raw material of end-THDC.
-100% by weight, preferably 5-90% by weight. It is not economical to use an excessively large amount, and if the amount is excessively small, the effect of using an inert solvent becomes poor.

The reaction temperature is not particularly limited, but is usually 40
To 150 ° C, preferably 50 to 130 ° C, more preferably 60 to 100 ° C. When the above-mentioned reaction solvent is not used, it is necessary to heat the raw material to a temperature higher than the melting point of the end-THDC to react it in a liquid state. Although the reaction time is not particularly limited, it is generally 10 minutes to 20 hours, preferably 2 minutes.
0 minutes to 10 hours, more preferably 30 minutes to 5 hours.

The amounts of the catalyst and cocatalyst used and the method of addition have been described above. The method of post-treatment of the isomerization reaction is not particularly limited, and a method generally used industrially may be applied. For example, examples of the method for removing the catalyst include a filtration method and a method in which alkaline water is added to dissolve the catalyst. Purification of the target substance may be performed according to a conventional method.

Object: exo-THDC The exo-THDC obtained by the method of the present invention is a solvent having no unsaturated bond in the molecule and having little irritating property to human skin and mucous membrane. It is preferably applied to technical applications. Its uses include, for example, paint solvents, diluents, surfactant diluents, waxes, cleaners, polish diluents, detergents, mold release agents, semiconductor detergents, blanket detergents, metalworking detergents, Solvents for agricultural chemicals, auxiliary solvents for pressure sensitive paper, cleaning solvents, aluminum rolling oil, ink solvents, resin dispersants, lubricating oils, punching oils, cutting oils and the like.

[0028]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is not limited to these examples. Parts and% in Examples and Comparative Examples are by weight unless otherwise specified. The analysis of the purity and the yield of the raw material and the reaction product was performed by gas chromatography (GC) analysis.
The analysis conditions are shown below.

GC equipment: GC-14A manufactured by Shimadzu Corporation Column: HP5 (30 m capillary column, inner diameter 0.3
2 mm), Injection temperature: 200 ° C, Column heating condition: Hold at 50 ° C for 12 minutes, and 280 ° C at 10 ° C / 1 minute
And maintained at 280 ° C for 5 minutes, developing gas: helium, internal standard material: normal decane

Production Example 1 Production of End-THDC An autoclave equipped with a stirrer was charged with 157 parts of dicyclopentadiene manufactured by Zeon Corporation and 1.5 parts of 5% palladium carbon. The inside of the autoclave was replaced with nitrogen gas several times. After the inside of the autoclave was replaced with hydrogen gas several times, hydrogen gas of 0.6 MPa (gauge pressure) was pressurized. The contents were hydrogenated at 100 ° C. for 2 hours while stirring. After the completion of the reaction, hydrogen gas was released, and the content was filtered while hot (about 80 ° C.) to remove the catalyst. The obtained filtrate (150 parts) immediately solidified in the filter receiver. A small amount of this solid was collected, dissolved in toluene, and analyzed by GC. As a result, no peak of dicyclopentadiene as a raw material was observed. The retention time of the main component was completely consistent with that of the end-THDC standard, and its purity was 94.5%. Impurities are components having a shorter GC retention time than endo-THDC (low-boiling components in Tables 1 to 5): 4.1%, endo-THDC
Components having a longer GC retention time (high boiling components in Tables 1 to 5):
It was 1.4%.

Example 1 In a glass reactor equipped with a stirrer, a reflux condenser, and a thermometer, 15 g of the endo-THDC (raw material) obtained in Production Example 1 and 10 g of methylcyclohexane (reaction solvent) were prepared.
g, powdered anhydrous aluminum chloride (catalyst) 0.3
75 g (2.5% based on endo-THDC) and 0.13 g aluminum chloride hexahydrate (promoter) (about 35% based on catalyst) were charged. The contents were heated to 80 ° C. and the isomerization reaction was carried out for 4 hours while stirring well. A small amount of the reaction solution was collected every hour, and the progress of the reaction was examined by GC analysis. After completion of the reaction, 5 g of a 25% aqueous sodium hydroxide solution was added, and the mixture was stirred at 50 ° C. for 30 minutes, and then cooled to room temperature. The aqueous layer separated from the two layers was removed to obtain 24.6 g of an oil layer. Table 1 shows the composition (%) of the reaction solution determined by GC analysis. However, in Table 1, the reaction solvent is excluded.

[0032]

[Table 1]

Example 2 Investigation of the isomerization reaction and the progress of the reaction in the same manner as in Example 1 except that the reaction solvent methylcyclohexane used in Example 1 was replaced with the exo-THDC obtained in Example 1. Was done. In this embodiment, the target substance, exo-THD, is used.
Example 2 differs from Example 1 in that C was used as a reaction solvent. The reaction solution was worked up as in Example 1 to give 24.3 g of an oily product.
I got Table 2 shows the results of GC analysis of the course of the reaction. However, in Table 2, exo-T initially charged as a reaction solvent was used.
HDC is excluded.

[0034]

[Table 2]

As can be seen from Tables 1 and 2, even at a reaction temperature as low as 80 ° C., the raw material end-THDC was obtained 2 hours after the start of the reaction.
Is converted to the desired exo-THDC. In addition, it can be seen that the generation of by-products (tetralin, adamantane) is suppressed.

Example 3 The end-THDC15 obtained in Production Example 1 was placed in a glass reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer.
g (solid) was charged. The reaction vessel was heated to 85 ° C. to dissolve the endo-THDC. A mixture of 0.375 g of powdered anhydrous aluminum chloride (catalyst) and 0.13 g of aluminum chloride hexahydrate (cocatalyst) was added thereto. The isomerization reaction was performed at an internal temperature of 80 ° C. for 4 hours with good stirring. Collect a small amount of the reaction solution every hour and
The course of the reaction was investigated by C analysis. After completion of the reaction, 5 g of a 25% aqueous sodium hydroxide solution was added, and the mixture was stirred at 50 ° C. for 30 minutes, and then cooled to room temperature. The aqueous layer separated into two layers was removed to obtain 14.7 g of an oil layer. Table 3 shows the results of GC analysis of the course of the reaction.

[0037]

[Table 3]

From Table 3, it can be seen that one hour after the start of the reaction, most of the starting endo-THDC was converted to the desired exo-THDC. In addition, it can be seen that the generation of by-products (tetralin, adamantane) is suppressed.

Comparative Example 1 The isomerization reaction and the progress of the reaction were investigated in the same manner as in Example 2 except that the cocatalyst used in Example 2 was not used. Table 4 shows the results of GC analysis of the course of the reaction.

[0040]

[Table 4]

Comparative Example 2 The isomerization reaction and the progress of the reaction were investigated in the same manner as in Example 3 except that the cocatalyst used in Example 3 was not used. Table 5 shows the results of GC analysis of the course of the reaction.

[0042]

[Table 5]

From Tables 4 and 5, it can be seen that when no cocatalyst is used, the catalytic activity is reduced and the reaction rate is significantly reduced. In addition, compared to Tables 1 to 3, End-THD
It can be seen that although the conversion of C is low, the generation of by-products tends to increase.

[0044]

The method of the present invention is an improved method for producing endo-THDC using a co-catalyst, which can suppress the formation of by-products and greatly reduce the reaction time as compared with the conventional method. This has an industrially extremely advantageous effect that it can be shortened.

Claims (5)

[Claims] 1. A process for producing exo-tetrahydrodicyclopentadiene by isomerizing endo-tetrahydrodicyclopentadiene in the presence of an anhydrous aluminum halide catalyst, characterized in that hydrated aluminum halide is used as a co-catalyst. For producing exo-tetrahydrodicyclopentadiene. 2. The method according to claim 1, wherein the anhydrous aluminum halide is anhydrous aluminum chloride, and the aluminum halide hydrate is aluminum chloride hexahydrate. 3. The method according to claim 1, wherein the amount of the promoter used is 2 to 100% by weight based on the weight of the catalyst. 4. The production method according to claim 1, wherein the isomerization is performed in the presence of an inert solvent. 5. The method according to claim 4, wherein the inert solvent is exo-tetrahydrodicyclopentadiene, and the used amount thereof is 5 to 90% by weight based on endo-tetrahydrodicyclopentadiene.