JP2000226356A - Method for production of dialkyl decahydronaphthalenedicarboxylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a dialkyl decahydronaphthalenedicarboxylate, especially its transisomer by the hydrogenation of a dialkyl naphthalenedicarboxylate. SOLUTION: This method is to perform the hydrogenation of a dialkyl naphthalenedicarboxylate under a pressure from atmospheric pressure to 15 MPa at 40-150 deg.C in the presence of a hydrogenation-inert solvent and a ruthenium catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a dialkyl naphthalenedicarboxylate (hereinafter referred to as "NDCE") obtained by hydrogenation of a dialkyl didecahydronaphthalenedicarboxylate (hereinafter referred to as "DDCE"), particularly a high ratio of trans isomers. The present invention relates to a method for producing DDCE.

[0002]

2. Description of the Related Art DDCE is used as a modifier for polyester.
Decahydronaphthalenedimethanol obtained by hydrogenating DDCE is used as a polymer material, and is a compound useful as, for example, a polyester, polyurethane, or polycarbonate resin or a diol component of a fiber. As a method for producing DDCE by hydrogenating NDCE, a method for catalytically reducing dimethyl naphthalenedicarboxylate is known. Japanese Patent Application Laid-Open No. 8-27067 discloses a method using a palladium and rhodium catalyst.
No. 60 describes an example using a platinum catalyst.

[0003]

It is known that cis and trans isomers exist in decahydronaphthalene obtained by hydrogenating naphthalene, depending on the configuration of the bridged carbon. The corresponding cis and trans isomers are also formed in DDCE obtained by hydrogenating NDCE. Neither of the above-mentioned JP-A-6-236860 nor JP-A-8-27067 has any description regarding the production of isomers, but DDCE obtained by any of the methods is a mixture of a mixture of cis and trans isomers. Become.

[0004] DDCE is hydrogenated to decahydronaphthalenedimethanol and used as a polymer material. When DDCE is used as a raw material for such a polymer material, the purity of the isomer of DDCE depends on the physical properties of the resulting polymer. It is considered to have a great effect, and it is necessary to obtain DDCE with as high an isomer purity as possible in order to produce a polymer material of stable quality. It is an object of the present invention to provide DDCE, in particular D
An object of the present invention is to provide a method for efficiently producing DCE.

[0005]

Means for Solving the Problems The present inventors have proposed NDCE.
As a result of intensive studies on a method for producing DDCE by hydrogenation of NDCE, the use of a ruthenium-based catalyst in the hydrogenation of NDCE allows the reaction to proceed at lower temperature conditions, and the trans isomer in the resulting DDCE mixture. The present inventors have found that the proportion of the body increases, and have completed the present invention. That is, the present invention is a process for producing a dialkyl decahydronaphthalenedicarboxylate, comprising hydrogenating a dialkyl naphthalenedicarboxylate in the presence of a solvent inert to hydrogenation and a ruthenium catalyst.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION NDCE as a raw material of the present invention is
It is an ester obtained from naphthalenedicarboxylic acid and alcohol, and naphthalenedicarboxylic acid is usually used in 2,6-form, and the alcohol is methanol, ethanol,
Fatty alcohols such as 2-propanol and ethylene glycol are used. In the present invention, dimethyl 2,6-naphthalenedicarboxylate is the most preferred raw material.

[0007] Since the hydrogenation performed in the present invention is an exothermic reaction, it is preferable to use a solvent in order to suppress an increase in temperature due to heat of reaction. As the solvent, a raw material which dissolves NDCE as a raw material or DDCE as a product and is inactive in a hydrogenation reaction is used. Alcohols such as methanol, ethanol, 2-propanol and ethylene glycol, or tetrahydrofuran, dioxane, diethylene glycol dimethyl ether and the like are used. Ethers, n-hexane, cyclohexane,
Saturated hydrocarbons such as n-heptane, acetic acid, ethyl acetate and the like are preferably used. The raw material NDCE is used after being diluted with a solvent so as to have a concentration of 1 to 50% by weight, preferably 5 to 30% by weight.

As the hydrogenation catalyst, a ruthenium-based catalyst is preferably used because it has a high activity and the reaction proceeds at a low temperature. The form of the catalyst may be an unsupported metal or a form supported on a carrier, but it is preferable to use the catalyst without the support because the activity is high and the reaction proceeds at a lower temperature. When supported on a carrier, the carrier is generally used activated carbon, diatomaceous earth, alumina, silica, silica alumina, zeolite, or the like, and is not particularly limited. When using a supported catalyst, the supported amount of ruthenium is 0.1 to 10% by weight of the total weight of the catalyst,
Preferably it is 0.5 to 5% by weight.

[0009] The temperature during the hydrogenation reaction is from 40 to 150 ° C, preferably from 50 to 130 ° C. When the temperature is lower than this temperature range, the reaction rate is low, and when the temperature is higher, decomposition products are generated and the ratio of trans isomers is low, which is not preferable. The hydrogen pressure during the hydrogenation reaction is from normal pressure to 15 MPa,
Preferably it is in the range of 1 to 10 MPa. The higher the reaction pressure, the higher the reaction rate. However, if the reaction pressure is too high, it causes a side reaction or a decomposition reaction, resulting in a decrease in yield.

[0010] The reaction system in the present invention includes a method using a liquid phase suspension bed, in which a hydrogenation catalyst is dispersed in a reaction solution.
Alternatively, any method of a fixed bed flow reaction in which a hydrogenation catalyst is fixed in a reactor and a reaction solution is allowed to act on the hydrogenation catalyst can be employed. In the present invention, hydrogenation is performed at a low temperature by using a ruthenium-based catalyst, and DDCE containing a high proportion of trans isomer can be efficiently produced.

[0011]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

Example 1 0.5 g of 2,6-naphthalenedicarboxylic acid dimethyl ester, 0.1 g of ruthenium black (manufactured by NE Chemcat) and 5 g of diethylene glycol dimethyl ether were charged into a 30 ml stainless steel autoclave, and after substituting with hydrogen, the first hydrogen was added. The pressure was adjusted to 5 MPa at room temperature, and the temperature was raised to 70 ° C. And
The reaction was stirred at a reaction temperature of 70 ° C. for 2 hours to complete the hydrogenation reaction. After the completion of the reaction, the reaction system was cooled to room temperature, hydrogen in the system was released, and the reaction product was recovered. When the product was analyzed by gas chromatography, 2,6-naphthalenedicarboxylic acid dimethyl ester conversion 100%, 2,6-decahydronaphthalenedicarboxylic acid dimethyl ester yield 99%
The trans isomer accounted for 80.5% of the total.

Example 2 A reaction was carried out in the same manner as in Example 1 except that the reaction temperature was changed to 100 ° C. The conversion of 2,6-naphthalenedicarboxylic acid dimethyl ester is 100%, and the yield of 2,6-decahydronaphthalenedicarboxylic acid dimethyl ester is 99%, of which tra
The proportion of the ns isomer was 75.0%.

Example 3 A reaction was carried out in the same manner as in Example 2 except that the catalyst was changed to 2 g of 5% Ru-C (manufactured by NE Chemcat). The conversion of 2,6-naphthalenedicarboxylic acid dimethyl ester is 100%, the yield of 2,6-decahydronaphthalenedicarboxylic acid dimethyl ester is 99%, of which the trans isomer accounts for 74.2%
Met.

Example 4 A reaction was carried out in the same manner as in Example 2 except that the solvent was changed to acetic acid. The conversion of 2,6-naphthalenedicarboxylic acid dimethyl ester was 100%, and the yield of 2,6-decahydronaphthalenedicarboxylic acid dimethyl ester was 99%, of which the ratio of the trans isomer was 73.3%.

Example 5 A reaction was carried out in the same manner as in Example 2 except that ethanol was used as the solvent. The conversion of 2,6-naphthalenedicarboxylic acid dimethyl ester is 100%, and the yield of 2,6-decahydronaphthalenedicarboxylic acid dimethyl ester is 99%, of which tra
The ratio of the ns isomer was 73.8%.

Example 6 A reaction was carried out in the same manner as in Example 1 except that the reaction temperature was changed to 180 ° C. The conversion of 2,6-naphthalenedicarboxylic acid dimethyl ester is 100%, and the yield of 2,6-decahydronaphthalenedicarboxylic acid dimethyl ester is 92%, of which tra
The proportion of the ns isomer was 58%.

[0018]

As is clear from the above examples, the present invention provides an industrially useful decahydronaphthalene by performing a catalytic hydrogenation reaction using a ruthenium-based catalyst and a dialkyl naphthalene dicarboxylate as a raw material. Production of dialkyl dicarboxylate in high yield
The rans isomer can be obtained with high selectivity. In the present invention, since a specific isomer can be obtained with a high selectivity, the yield after separation and purification is good and economical. Therefore, according to the present invention, dialkyl decahydronaphthalenedicarboxylate can be produced inexpensively and efficiently, and the present invention has great industrial significance.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Minoru Takakawa 22nd Wadai, Tsukuba, Ibaraki Pref. BT22 FC24

Claims (3)

[Claims] 1. A process for producing dialkyl decahydronaphthalenedicarboxylate, comprising hydrogenating a dialkyl naphthalenedicarboxylate in the presence of a solvent inert to hydrogenation and a ruthenium-based catalyst. 2. Hydrogenation at a pressure of normal pressure to 15 MPa at a temperature of 40 to 150 ° C., and a trans product for the cis isomer of the dialkyl decahydronaphthalenedicarboxylate obtained.
The method for producing a dialkyl decahydronaphthalenedicarboxylate according to claim 1, wherein the ratio of the isomers is 2 or more. 3. The method for producing a dialkyl decahydronaphthalenedicarboxylate according to claim 1, wherein the solvent is at least one compound selected from alcohols, ethers, lower fatty acids, lower fatty acid esters and saturated hydrocarbons. .