JP2003128593A - Method for producing exo-tetrahydrodicyclopentadiene - Google Patents

Abstract

(57) [Problem] To provide a method for producing high-purity exo-tetrahydrodicyclopentadiene (exo-THDC) with high yield using dicyclopentadiene (DCP) as a starting material. A process for hydrogenating DCP in the presence of a hydrogenation catalyst to obtain endo-tetrahydrodicyclopentadiene (endo-THDC), and the obtained endo-THD
Isomerizing C in the presence of a Friedel-Crafts type acid catalyst to obtain exo-THDC.
A method for producing THDC, wherein said DCP is 5-
A process for producing exo-tetrahydrodicyclopentadiene, comprising using DCP having a total content of propenyl norbornene and 5-isopropenyl norbornene of less than 2% by weight.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for hydrogenating dicyclopentadiene to obtain endo-tetrahydrodicyclopentadiene and then freeing the obtained endo-tetrahydrodicyclopentadiene. The present invention relates to an improved method for producing exo-tetrahydrodicyclopentadiene by isomerization in the presence of a Del-Crafts type acid catalyst. [0002] Exo-tetrahydrodicyclopentadiene (hereinafter also referred to as "exo-THDC") has been known for use as a paint, a diluent such as a surfactant, a jet fuel and the like. I have. Also recently, electronic components,
It is also attracting attention as a cleaning solvent for precision machine parts. Conventionally, as a method for producing exo-THDC, dicyclopentadiene is hydrogenated in the presence of a hydrogenation catalyst, and then the obtained endo-tetrahydrodicyclopentadiene (hereinafter referred to as “endo-THDC”). Isomerized in the presence of a Friedel-Crafts acid catalyst such as anhydrous aluminum chloride to give exo-TH
A method for obtaining DC is known (for example, see Japanese Unexamined Patent Publication No.
No. 13370, JP-A-57-32232, JP-A-58-18324, U.S. Pat.
No. 4, etc.). [0004] However, the exo-THDC obtained by the above-mentioned production method contains impurities, and even if distillation is carried out using a high number of rectification columns, exo-THDC cannot be obtained. The purity of THDC cannot be increased,
There was a problem that the distillation yield was low. The present invention has been made under such circumstances, and it is an object of the present invention to provide a production method capable of obtaining high-purity exo-THDC with high yield from dicyclopentadiene as a starting material. . Means for Solving the Problems In order to solve the above problems, the present inventors have studied in detail a reaction for obtaining exo-THDC by hydrogenating and isomerizing dicyclopentadiene. As a result, the obtained exo-THD
Even if C is rectified using a rectification column having a high number of stages, its purity cannot be increased and the distillation yield is low because 5-propenylnorbornene and 5-propenylnorbornene contained in the starting material dicyclopentadiene are reduced. -It has been found that a substance derived from isopropenyl norbornene is contained in exo-THDC in a considerable amount as an impurity. Therefore, dicyclopentadiene having a total content of 5-propenylnorbornene and 5-isopropenylnorbornene of less than 2% by weight is used as dicyclopentadiene used as a raw material. Then, by using this as a raw material, it was found that exo-THDC having extremely high purity can be obtained with a high yield and the distillation yield also increased, and the present invention was completed. Thus, according to the present invention, a step of hydrogenating dicyclopentadiene in the presence of a hydrogenation catalyst to obtain endo-tetrahydrodicyclopentadiene, and a step of converting the obtained endo-tetrahydrodicyclopentadiene to a Friedel-Crafts type Isomerizing in the presence of an acid catalyst to obtain exo-tetrahydrodicyclopentadiene, wherein the dicyclopentadiene is 5-5-
There is provided a process for producing exo-tetrahydrodicyclopentadiene, comprising using dicyclopentadiene having a total content of propenyl norbornene and 5-isopropenyl norbornene of less than 2% by weight. Hereinafter, the manufacturing method of the present invention will be described in detail. In the method of the present invention, dicyclopentadiene (hereinafter, also referred to as “DCP”) is hydrogenated to form endo-TH.
It comprises a step of obtaining DC and a step of isomerizing the obtained endo-THDC to obtain exo-THDC (see the following reaction formula). [0010] (In the formula, endo and exo represent the stereoisomeric structure of each compound.) DCP as a raw material has a boiling point of about 170 ° C. and a melting point of about 17 ° C.
° C. This is the cyclopentadiene 2
When cyclopentadiene is left at room temperature, it is easily dimerized to DCP. Conversely, 140-160 ° C
When heated to a thermal decomposition (depolymerization), cyclopentadiene is given. [0012] DCP is obtained, for example, by extracting the remaining C ₅ obtained by extracting isoprene from the C ₅ fraction by-produced during the thermal decomposition of naphtha.
The fraction can be obtained by dimerizing the fraction and distilling the obtained fraction containing a large amount of DCP (DCP content: about 30 to 70% by weight). The DCP obtained by this method has a purity of about 92 to 97% by weight (hereinafter, such a DCP may be referred to as “low-purity DCP”), and as impurities, propenyl norbornene, isopropenyl norbornene, vinyl norbornene, Including tricyclopentadiene and the like. Among these, 5-propenylnorbornene and 5-isopropenylnorbornene are the main impurities. According to the present invention, DCP used as a raw material is 5
DCP having a total content of -propenylnorbornene and 5-isopropenylnorbornene of less than 2% by weight (hereinafter, referred to as DCP)
This is called "high-purity DCP". ) Is used. Here, 5-propenylnorbornene and 5-isopropenylnorbornene may have a cis isomer and a trans isomer based on a double bond, but in the present invention, all of 5-propenylnorbornene and 5-isopropenylnorbornene are used. DCP having a total content of isomers of less than 2% by weight is used. [0014] High-purity DCP can be obtained by purifying the low-purity DCP. The method for purifying low-purity DCP is not particularly limited. For example, a method for purifying low-purity DCP by distillation or column chromatography can be used. Among these, the distillation method is preferred from the viewpoint of simplicity and handleability. As a distillation method for obtaining high-purity DCP, for example, a method of rectifying low-purity DCP using a distillation apparatus equipped with a high-stage rectification column, or a method of distilling low-purity DCP by heat decomposition. After obtaining high-purity cyclopentadiene, dimerization is again performed to obtain DCP, and this is distilled using a rectification apparatus generally used industrially. In the production method of the present invention, first, endo-THDC is obtained by a hydrogenation reaction of hydrogenating the high-purity DCP obtained as described above in the presence of a hydrogenation catalyst. The hydrogenation reaction is nickel, cobalt, iron, titanium,
It can be carried out by a known catalytic reduction method using a hydrogenation catalyst containing at least one metal selected from rhodium, palladium, platinum, ruthenium, rhenium and the like. Each of these hydrogenation catalysts may be used alone,
Two or more kinds may be used in combination. The amount of the hydrogenation catalyst is usually 0.01 to 100 parts by weight of DCP.
To 50 parts by weight, preferably 0.05 to 20 parts by weight, more preferably 0.1 to 10 parts by weight. The hydrogenation reaction can be carried out without solvent or in the presence of an inert solvent. As the inert solvent used, for example, benzene, toluene, ethylbenzene,
Aromatic hydrocarbons such as xylene, chlorobenzene and dichlorobenzene; chain aliphatic hydrocarbons such as n-pentane, n-hexane, isohexane, n-heptane, n-octane, n-nonane, n-decane and n-undecane Cyclic aliphatic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane and decalin. As a method of the hydrogenation reaction, any of a continuous type and a batch type can be adopted. However, since the boiling point of DCP is about 170 ° C., the reaction is carried out in a reaction vessel such as a metal or glass autoclave. A predetermined amount of DCP, a hydrogenation catalyst and, if desired, an inert solvent are charged, the inside of the reaction vessel is replaced with an inert gas such as nitrogen gas, and then completely replaced with hydrogen. A batch type in which the contents are stirred below is preferred. The hydrogen pressure at this time is usually 0.1 MPa to 30 MPa, preferably 1 MPa.
a to 20 MPa, more preferably 2 MPa to 10 MPa
It is. The reaction temperature of the hydrogenation reaction is usually 10
C. to 250C, preferably 50C to 200C, more preferably 80C to 180C. When the reaction is carried out without solvent, the resulting endo-THDC is solid at room temperature (melting point 7).
7 ° C.), it is preferable to carry out the hydrogenation in the liquid phase with the reaction temperature being equal to or higher than the melting point of endo-THDC. The reaction time of the hydrogenation reaction is usually 0.5 hours to 50 hours. The hydrogenation reaction product can be obtained by a known method, for example, by filtering off the hydrogenation catalyst from the reaction solution, evaporating the solvent from the obtained filtrate as needed, and distilling the residue. Alternatively, it can be isolated by a method of adding a lower aliphatic alcohol or the like to the residue to precipitate the desired product. Further, the solution obtained by removing the hydrogenation catalyst from the reaction solution without isolating the hydrogenation reaction product can be directly used for the next isomerization reaction. DCP usually exists as a thermodynamically stable endo compound (compound represented by “endo-DCP” in the above reaction formula). In this hydrogenation step, endo-THDC is not isomerized to exo-THDC, so that a hydride having an endo structure (endo-THDC) is obtained by the hydrogenation reaction. The raw material DCP
Is also hydrogenated at the same time, but the side reaction does not proceed. Therefore, by hydrogenating high-purity DCP, endo-THDC having a purity of usually 98% by weight or more, preferably 99% by weight or more can be obtained. Next, the obtained endo-THDC is isomerized in the presence of a Friedel-Crafts type acid catalyst to obtain exo-THDC. The Friedel-Crafts acid catalyst used in the present invention is a Lewis acid catalyst used for a so-called Friedel-Crafts reaction of an aromatic compound. Specific examples thereof include: (a) metal halides such as aluminum halide, ferric halide, zinc halide, varnish halide, titanium halide; (b) anhydrous aluminum halide and aluminum halide A catalyst obtained by adding a hydrate (promoter) of (c);
Examples include a catalyst obtained by adding a cocatalyst such as t-butyl chloride, isopropyl bromide, and ethyl bromide, and a catalyst (d) obtained by reacting anhydrous aluminum halide with hydrogen halide in the presence of a solvent. . Among these, from the viewpoint of obtaining the desired product in good yield, it is preferable to use an anhydrous aluminum halide, a Friedel-Crafts acid catalyst of (b), (c) or (d). The amount of the Friedel-Crafts type acid catalyst used is as follows: End-THDC
To 0.1% by weight, preferably 0.2% to
It is 15% by weight, more preferably 0.5 to 10% by weight. The isomerization reaction is carried out by putting a predetermined amount of endo-THDC, an inert solvent and a Friedel-Crafts acid catalyst as required in a reaction vessel, and heating and stirring the contents at a predetermined temperature. When the anhydrous aluminum halide and the cocatalyst or cocatalyst are used in combination as the Friedel-Crafts type acid catalyst, the Friedel-Crafts type acid catalyst is added in advance by adding a cocatalyst or a cocatalyst to the anhydrous aluminum halide. It may be prepared and added to the reaction system, or anhydrous aluminum halide and co-catalyst or co-catalyst may be separately added to the reaction system. When the isomerization reaction is carried out in the presence of an inert solvent, examples of the inert solvent used include aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene; n-pentane, n-hexane and isohexane. ,
Chain aliphatic hydrocarbons such as isoheptane, n-octane, isooctane, n-nonane, n-decane, isodecane, n-undecane, n-tridecane; cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclo Octane, decalin,
And cyclic aliphatic hydrocarbons such as paramenthane and bicyclohexyl. In general, the desired exo-THDC
The use of an inert solvent having a boiling point close to that of the above has a problem that the purification of the target product becomes complicated, but the use of exo-THDC itself as a reaction solvent does not hinder any problem and is preferably used in the present method. The amount of the inert solvent used is not particularly limited, but is usually 2 to 100% by weight based on the endo-THDC,
Preferably it is 5-90% by weight. Excessive use is not economical and too small an effect of using an inert solvent is poor. The reaction temperature of the isomerization reaction is not particularly limited, but is usually 40 to 150 ° C., preferably 50 to 130 ° C.
More preferably, it is 60 to 100 ° C. When an inert solvent is not used, it is necessary to heat the raw material to a temperature higher than the boiling point of endo-THDC to react it in a liquid state. The reaction time is generally 10 minutes to 20 hours, preferably 20 minutes to 10 hours.
Time, more preferably 30 minutes to 5 hours. After completion of the reaction, insolubles are separated from the reaction solution by filtration and the filtrate is distilled, or the reaction solution is poured into ice-cooled water or ice-cooled alkaline water, an oil layer is separated, and the oil layer is distilled. Thus, the desired exo-THDC
Can be obtained. As the distillation method, any of a normal pressure distillation method and a reduced pressure distillation method can be used, but exo-THDC
Since is a liquid having a boiling point of 187 ° C., a vacuum distillation method is preferred. As the distillation apparatus, any of a batch distillation apparatus and a continuous distillation apparatus can be used, but it is preferable to use a continuous rectification apparatus for industrial production. Further, the distillation can be performed a plurality of times as necessary. According to the conventional method, the exo-THDC obtained by the isomerization reaction contains a considerable amount of impurities derived from 5-propenylnorbornene and / or 5-isopropenylnorbornene contained in the starting DCP. Therefore, even if rectification was performed using a high-stage rectification column, the purity of exo-THDC could not be increased, and the distillation yield was low. In the present invention, since DCP having a total content of 5-propenylnorbornene and 5-isopropenylnorbornene of less than 2% by weight is used as a raw material, the content of impurities derived from 5-propenylnorbornene and / or 5-isopropenylnorbornene is reduced. Exo with very little
THDC can be obtained. Therefore, by purifying the isomerization reaction product by a distillation method, it is usually 98% by weight or more, preferably 99% by weight or more, more preferably 9% by weight or more.
Exo-THDC having a purity of 9.5% by weight or more can be obtained in good yield. The exo-THD obtained as described above
C is a solvent having no unsaturated bond in the molecule and having little irritation to human skin or mucous membrane, and is preferably applied to various industrial uses. Its applications include, for example, diluents such as paints, surfactants, waxes, cleaners, and polish; detergents for electronic components, precision machine components, semiconductors, blankets, etc .; detergents for metalworking, mold release agents, and agricultural chemicals. Solvents, auxiliary solvents for pressure-sensitive dyes, cleaning solvents, aluminum rolling oil, ink solvents, resin dispersants, lubricating oils, punching oils, cutting oils and the like. In particular, the exo-THDC obtained by the production method of the present invention has a very high purity, and can be preferably applied to cleaning applications for electronic parts, precision mechanical parts, semiconductors, and the like. EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, 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 yield of the starting materials and reaction products was performed by gas chromatography (GC).
The conditions for GC analysis are shown below. GC equipment: GC-14A (manufactured by Shimadzu Corporation) Column: HP5 (30 m capillary column, inner diameter of 0.1 mm)
Injection temperature: 200 ° C Column heating condition: Hold for 12 minutes at 50 minutes → Heat up to 280 ° C at 10 ° C / 1 minute → Hold at 280 ° C for 5 minutes Carrier gas: Helium Internal standard substance: n-decane Example 1 Preparation of exo-tetrahydrodicyclopentadiene (1) Purification of dicyclopentadiene Purity of about 9 containing about 3% by weight of 5-propenylnorbornene and 5-isopropenylnorbornene as impurities.
7% by weight of dicyclopentadiene (Nippon Zeon Co., Ltd.)
Was distilled using a distillation apparatus equipped with a rectification column having 5 theoretical plates to obtain 190 parts of dicyclopentadiene. As a result of GC analysis of this product, the purity of the obtained dicyclopentadiene was 99% by weight, and 5-propenylnorbornene and 5
-Isopropenyl norbornene was contained in a total of 0.9% by weight. (2) Hydrogenation reaction of dicyclopentadiene In an autoclave equipped with a stirrer, 157 parts of the dicyclopentadiene having a purity of 99% by weight obtained in the above (1) and 5%
1.5 parts of palladium carbon was charged, and the inside of the autoclave was replaced several times with nitrogen gas. Next, after replacing the inside of the autoclave with hydrogen gas several times, a hydrogen gas of 0.6 MPa (gauge pressure) was pressurized. 10 while stirring the contents
A hydrogenation reaction was performed at 0 ° C. for 2 hours. After the completion of the reaction, hydrogen gas in the system was released, and the reaction product was filtered while hot (about 80 ° C.) to remove the catalyst. The resulting filtrate (150 parts) solidified immediately 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 gas chromatography retention time of the main component was completely the same as that of the sample of endo-tetrahydrodicyclopentadiene, and the purity was 99% by weight. (3) Isomerization reaction of endo-tetrahydrodicyclopentadiene The endo-tetrahydrodicyclopentadiene 135 obtained in the above (2) is placed in a glass reaction vessel equipped with a stirrer, a reflux condenser and a thermometer. , 90 parts of n-hexane and 4.6 parts of aluminum trichloride pulverized. The contents were heated to 80 ° C., and an isomerization reaction was carried out at the same temperature for 7 hours while stirring well. After the completion of the reaction, the reaction solution was allowed to cool, and insolubles in the reaction system were separated by filtration. The obtained crude product was rectified under reduced pressure using a distillation apparatus equipped with a distillation column having 5 theoretical plates, whereby a boiling point of 100 ° C. (45 mmH
120 parts of the fraction of g) were obtained. This product did not solidify at room temperature, and as a result of GC analysis, a peak completely coincided with that of a sample of exo-tetrahydrodicyclopentadiene. The purity of the obtained exo-tetrahydrodicyclopentadiene was 99.5% by weight. Comparative Example 1 Preparation of exo-tetrahydrodicyclopentadiene In Example 1, the purity was 99% by weight as a starting material.
157 parts of dicyclopentadiene having a purity of 97% by weight (containing a total of 2.9% by weight of 5-propenylnorbornene and 5-isopropenylnorbornene as impurities) in place of 157 parts of dicyclopentadiene
A hydrogenation reaction and an isomerization reaction were performed in the same manner as in Example 1. The reaction solution was post-treated in the same manner as in Example 1 and purified by distillation to obtain exo-tetrahydrodicyclopentadiene. As a result of GC analysis, the purity of exo-tetrahydrodicyclopentadiene was 97% by weight.
This exo-tetrahydrodicyclopentadiene is added to 50
The rectification was performed using a through-the-pack of the stage, but the purity and distillation yield of exo-tetrahydrodicyclopentadiene could not be increased. According to the production method of the present invention, high purity can be obtained by using dicyclopentadiene having a total content of 5-propenyl norbornene and 5-isopropenyl norbornene of less than 2% by weight as a starting material. Exo-tetrahydrodicyclopentadiene can be obtained in good yield.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Akira Tanaka             1-2-1 Night Light, Kawasaki-ku, Kawasaki-shi, Kanagawa               Inside Zeon Corporation General Development Center (72) Inventor Sumi Watanabe             1-2-1 Night Light, Kawasaki-ku, Kawasaki-shi, Kanagawa               Inside Zeon Corporation General Development Center F-term (reference) 4H006 AA02 AC11 AC27 BA09 BA25                       BA37 BA55 BB11 BC10 BC11                       BC19 BC34 BE20                 4H039 CA19 CB10 CJ10

Claims (1)

Claims: 1. A step of hydrogenating dicyclopentadiene in the presence of a hydrogenation catalyst to obtain endo-tetrahydrodicyclopentadiene, and converting the obtained endo-tetrahydrodicyclopentadiene to Friedel-Crafts Isomerization in the presence of a type acid catalyst to obtain exo-tetrahydrodicyclopentadiene, wherein the dicyclopentadiene is 5-propenylnorbornene and 5-propenylnorbornene. A process for producing exo-tetrahydrodicyclopentadiene, comprising using dicyclopentadiene having a total content of isopropenylnorbornene of less than 2% by weight.