JP2000136157A - Production of decahydronaphthalene dimethanol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for effectively producing decahydronaphthalene dimethanol without using an expensive reducing agent. SOLUTION: This method comprises the first step of hydrogenating a naphthalene ring of naphthalene dicarboxylic acid dialkyl ester in the presence of a rare metal catalyst and the second step of hydrogenating the alkyl ester site of the obtained reaction liquid in the presence of a copper chrome-based catalyst, while using the common solvent in both the steps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing decahydronaphthalenedimethanol (hereinafter, referred to as DDM) by catalytic hydrogenation of a dialkyl naphthalenedicarboxylic acid (hereinafter, referred to as NDCE). DDM
Is important as a monomer of a polymer material, for example, a diol component of a polyester resin, a polyurethane resin, and a polycarbonate resin.

[0002]

2. Description of the Related Art A method for producing 2,6-decahydronaphthalenedimethanol (2,6-DDM) from 2,6-naphthalenedicarboxylic acid dimethyl ester is disclosed in Japanese Patent Application Laid-Open No. 6-263860. Dimethyl 2,6-decalin dicarboxylate is obtained by catalytic reduction of dimethyl acid, which is reduced to alcohol with a reducing agent. In this example, catalytic reduction is performed with a 5% platinum carbon catalyst in a cyclohexane solvent. After that, a method of reducing to alcohol using sodium borohydride and lithium bromide as reducing agents in a diglyme solvent is performed.

[0003]

SUMMARY OF THE INVENTION The above-mentioned JP-A-6-26
In the method described in No. 3860, in the method of catalytically reducing dimethyl 2,6-naphthalenedicarboxylate to obtain dimethyl 2,6-decalin dicarboxylate, hydrogenation of the naphthalene ring is performed, and 2,6-decalin dicarboxylic acid is obtained. In the method of reducing dimethyl to alcohol, hydrogenation of the alkyl ester portion is performed. In the hydrogenation of the alkyl ester moiety according to the method described in JP-A-6-263860, a large amount of sodium borohydride and lithium bromide as reducing agents are required, which is economically expensive and increases the reaction cost. Subsequent post-treatment is complicated and industrially difficult to implement. In addition, cyclohexane is used as a solvent in the hydrogenation of naphthalene nuclei, and diglyme is used as a solvent in the hydrogenation of alkyl ester moieties. However, the use of two types of solvents complicates the separation / recovery process. However, this is not preferable for industrial implementation. An object of the present invention is to provide a method for efficiently producing decahydronaphthalenedi-methanol without using an expensive reducing agent.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for producing DDM having the above-mentioned problems, and as a result, when synthesizing DDM from NDCE,
By applying a two-stage catalytic hydrogenation reaction using a noble metal catalyst and a copper chromium catalyst in a single solvent system, the solvent recovery system is simplified and an expensive reducing agent is not required,
They have found that DDM can be obtained efficiently at low cost, and have reached the present invention.

That is, the present invention provides a first step of hydrogenating the naphthalene ring of a dialkyl naphthalenedicarboxylate in the presence of a noble metal catalyst in the production of decahydronaphthalenedimethanol from a dialkyl naphthalenedicarboxylate. The reaction product solution, in the presence of a copper chromium-based catalyst, comprises a second step of hydrogenating the alkyl ester portion, a method for producing decahydronaphthalenedi-methanol characterized by using a common solvent in both steps is there.

[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 an alcohol. Usually, 2,6 naphthalenedicarboxylic acids are used, and aliphatic alcohols such as methanol, ethanol, 2-propanol, and ethylene glycol are used as the alcohol. In the present invention, dimethyl 2,6-naphthalenedicarboxylate is the most preferred raw material.

In the present invention, since both the first and second steps are exothermic reactions, a solvent is used to suppress the heat of reaction. As a solvent, dissolve the raw material NDCE and the product DDM,
What is inert to the hydrogenation reaction is used, methanol, ethanol, 2-propanol, alcohols such as ethylene glycol, or tetrahydrofuran, dioxane,
Ethers such as diethylene glycol dimethyl ether are preferably used. The raw material NDCE has a concentration of 1 to 5
It is used after being diluted with a solvent so as to be 0% by weight, preferably 5 to 30% by weight.

In the first step, ruthenium, palladium,
Noble metal catalysts such as platinum and rhodium are used. It is better to use the catalyst in the form of precious metal supported on a carrier,
Examples of the carrier include generally used activated carbon, diatomaceous earth, alumina, silica, zeolite and the like, and are not particularly limited. The amount of the noble metal supported is 0.1 to 10 of the total weight of the catalyst.
%, Preferably 0.5 to 5% by weight. If the supported amount is too small, the activity per catalyst weight is reduced, and a large amount of the catalyst is required, which is not economical. If the amount is too large, it is not preferable because the reaction rate cannot be improved in proportion to the amount of the noble metal carried.

The reaction pressure in the first step is normal pressure to 10MP.
a, preferably 1 to 5 MPa. The higher the reaction pressure is, the higher the reaction rate is. However, if the reaction pressure is too high, it is not preferable because it causes a side reaction or a decomposition reaction and impairs the yield. The reaction temperature is from 80 to 300 ° C, preferably from 120 to 240 ° C.
It is.

By carrying out the reaction of the first step under the above conditions, the naphthalene ring of the raw material NDCE is hydrogenated, and a dialkyl hydrocaine naphthalenedicarboxylate is obtained. In the second step described below, the obtained decahydronaphthalenedicarboxylic acid dialkyl ester solution is hydrogenated to hydrogenate the ester portion, thereby obtaining the desired DDM.

The catalyst used in the second step is a copper chromium-based catalyst whose composition is in an oxidized state and the copper oxide is 1%.
The content of chromium oxide is preferably in the range of 5 to 50% by weight and the content of chromium oxide is preferably in the range of 15 to 50%. Outside this range, the amount of by-products is increased and the reaction yield is significantly reduced.

A feature of the present invention is that a common solvent is used in the first step and the second step. Therefore, the reaction product liquid in the first step can be used as it is as a raw material used in the second step, but the reaction may be further performed by adding the solvent used in the first step. The reaction pressure in the second step is 5
The pressure is 30 MPa, preferably 8 to 25 MPa. The higher the reaction pressure is, the higher the reaction rate is. However, if the reaction pressure is too high, it is not preferable because it causes a side reaction or a decomposition reaction and impairs the yield. The reaction temperature is 150-300 ° C, preferably 1
50-250 ° C.

The reaction system in the present invention may be a method using a liquid phase suspension bed in which a hydrogenation catalyst is dispersed in a reaction solution in both the first and second steps, or a method in which the hydrogenation catalyst is fixed in a reactor. Any of the methods using a fixed bed flow reaction in which a reaction solution is allowed to act on the reaction solution can be employed.

[0014]

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

Example 1 (First step) 7 g of 2,6-naphthalenedicarboxylic acid dimethyl ester (hereinafter referred to as 2,6-NDC), 15 g of diethylene glycol dimethyl ether, and a ruthenium-supported catalyst were placed in a 100 mL SUS316 shaking autoclave. 0.5 g of a 5% Ru-C powder (manufactured by NE Chemcat) was charged, and the inside of the vessel was replaced with hydrogen. Then, the temperature of the reactor was raised to 150 ° C. After heating, hydrogen pressure is 5MPa
And the shaking of the autoclave was started. After confirming that the hydrogen absorption had stopped after 1 hour, the autoclave was cooled and the remaining hydrogen was released. When the obtained reaction product liquid was analyzed by gas chromatography, 2,6-N
The reaction rate of DC is 100%, and dimethyl 2,6-decahydronaphthalenedicarboxylate (hereinafter referred to as 2,6-DDC) in the reaction product liquid excluding the solvent and light boiling components
Was 95%. (Second step) The catalyst was separated from the reaction product by filtration, and the filtrate was put into a newly prepared 100 mL SUS316 shaking autoclave, in which 2 g of a copper chromium catalyst (copper / chromium / manganese catalyst, manufactured by Nikki Chemical) was added. Was added and the inside of the vessel was replaced with hydrogen, and then the temperature was raised to 200 ° C. After heating, 20MPa hydrogen
The filling and the shaking of the autoclave were started. After confirming that the hydrogen absorption had stopped after 2 hours, the autoclave was cooled and the remaining hydrogen was released. When the obtained reaction product was analyzed by gas chromatography, 2,6-D
The reaction rate of DC is 100%, and the concentration of 2,6-DDM in the reaction product liquid excluding the solvent and light boiling components is 93%.
Met.

Example 2 A reaction was carried out in the same manner as in Example 1 except that 5% Pd-C was used instead of 5% Ru-C, and the reaction temperature in the first step was set at 180 ° C. The 2,6-NDC conversion in the first step was 100%, and the concentration of 2,6-DDC in the reaction product liquid excluding the solvent and light-boiling components was 93%.

Example 3 The reaction temperature in the second step was 250 ° C. and the reaction pressure was 25 MPa.
The reaction was conducted in the same manner as in Example 1 except that The conversion of 2,6-DDC in the second step is 100%,
2,6- of the components of the reaction product liquid excluding the solvent and light-boiling components
The concentration of DDM was 96%.

[0018]

As is clear from the above examples, according to the present invention, industrially useful decahydronaphthalenediethanol is obtained by performing a two-stage catalytic hydrogenation reaction using a naphthalenedicarboxylic acid dialkyl ester as a raw material. Can be efficiently produced in a very high yield. In the present invention, a two-step catalytic hydrogenation reaction can be carried out in a single solvent system, so that the solvent can be easily recovered. In addition, since the hydrogenation reaction of the alkyl ester portion is performed using a copper chromium-based catalyst, an expensive reduction is performed. No agent is required. Therefore, according to the present invention, decahydronaphthalenediethanol can be produced inexpensively and efficiently, and the present invention has great industrial significance.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C07C 35/23 C07C 35/23 // C07B 61/00 300 C07B 61/00 300 F term (reference) 4G069 AA03 AA15 BA01A BA02A BA07A BA08A BA08B BA09A BC31B BC58B BC62B BC70A BC70B BC72A BC72B BC75A CB02 CB65 CB70 DA06 4H006 AA02 AC11 AC41 BA05 BA14 BA23 BA25 BA26 BA30 BB14 BB15 BB25 BD70 BE20 FC32 FE11 4H039 CA40 CB10 CB10

Claims (4)

[Claims] 1. A first step of hydrogenating a naphthalene ring of a dialkyl naphthalenedicarboxylate in the presence of a noble metal catalyst in producing decahydronaphthalenedimethanol from a dialkyl naphthalenedicarboxylate, a reaction product obtained Comprises a second step of hydrogenating the alkyl ester portion in the presence of a copper chromium-based catalyst, wherein a common solvent is used in both steps. 2. The method for producing decahydronaphthalenedimethanol according to claim 1, wherein one or more metal compounds selected from ruthenium, palladium and platinum are used as the noble metal catalyst used in the first step. 3. The method according to claim 1, wherein 2,6-naphthalenedicarboxylic acid dimethyl ester is used as the naphthalenedicarboxylic acid dialkyl ester. 4. The method for producing decahydronaphthalenedi-methanol according to claim 1, wherein alcohols and / or ethers are used as a common solvent in the first step and the second step.