JP2000355564A - Production of glycol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stably carrying out a reaction for along time by suppressing the reduction of catalyst activities in producing a glycol by directly hydrogenating a dicarboxylic acid in an aqueous medium in the presence of a solid catalyst. SOLUTION: This production of a glycol is to carry out the reaction at <=270 deg.C and use a specific reactor in which the wetted part of a reaction zone having >=160 deg.C temperature and satisfying the formula: C>2,000/(T-100), where T( deg.C) is a temperature and C is a concentration (wt.%) of a dicarboxylic acid, is constituted of a nickel-based alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing glycol. In particular, the present invention relates to a method for suppressing the deterioration of the activity of a catalyst in producing a glycol by hydrogenating a dicarboxylic acid or an acid anhydride thereof in a liquid phase in the presence of a solid catalyst.

[0002]

It is well known to hydrogenate carboxylic acids to produce alcohols. The most common way is
It is a method via an ester. For example, Japanese Patent Publication No. 53-3
No. 3567 and Japanese Patent Publication No. 6-99345,
As a method for producing 1,6-hexanediol from an oxidation reaction product obtained by oxidizing cyclohexane, a method is described in which the oxidation reaction product is esterified with an alcohol, and the generated ester is hydrogenated in the presence of a solid catalyst. Have been. However, this ester-mediated method is industrially disadvantageous because of the long process.

Some methods have been proposed for producing alcohols by directly hydrogenating a carboxylic acid without passing through an ester. For example, JP-A-47-4767 and JP-A-49-13003 describe that hydrogenation is performed using a cobalt catalyst. In addition, Tokiko Sho 4
No. 9-33171 discloses a method using a rhenium catalyst,
Japanese Patent Application Laid-Open No. 9-59188 discloses a method using a Raney ruthenium catalyst.

[0004]

However, these methods are industrially disadvantageous in that the reaction must be carried out under severe conditions of high temperature and high pressure, and the conversion rate is remarkably reduced due to a decrease in the activity of the catalyst. It is not always satisfactory as a manufacturing method. Accordingly, an object of the present invention is to provide a method for producing an alcohol by directly hydrogenating a carboxylic acid while suppressing a decrease in the activity of a catalyst.

[0005]

According to the present invention, a dicarboxylic acid or an acid anhydride thereof is hydrogenated in an aqueous medium in the presence of a solid catalyst to produce a glycol. And the temperature in the reaction zone is 16
The part where the relationship between the temperature and the concentration of dicarboxylic acid or its anhydride at 0 ° C. or more satisfies the following formula (1) is defined by using a reactor in which the liquid contact surface is made of a nickel-based alloy. The reaction can be stably performed over a long period of time while suppressing the activity decrease.

[0006]

C> 2000 / (T-100) (1)

(Where T is the reaction temperature (° C.) and C is the concentration (% by weight) of dicarboxylic acid or its anhydride).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. Dicarboxylic acid or an acid anhydride thereof as a reaction raw material includes succinic acid, glutaric acid, adipic acid, pimelic acid,
4 carbon atoms such as suberic acid, azelaic acid and sebacic acid
Aliphatic saturated dicarboxylic acids having 10 to 10 carbon atoms; aliphatic unsaturated dicarboxylic acids having 4 to 10 carbon atoms such as maleic acid and fumaric acid;
Acid anhydrides of the above aliphatic dicarboxylic acids such as succinic anhydride and maleic anhydride; cyclohexanedicarboxylic acid,
4 carbon atoms such as 2-cyclohexanedicarboxylic anhydride
Alicyclic dicarboxylic acids having 10 to 10 or acid anhydrides thereof; and aromatic dicarboxylic acids having 4 to 10 carbon atoms such as phthalic acid, phthalic anhydride, isophthalic acid, and terephthalic acid, and acid anhydrides thereof. These compounds may be used alone or as a mixture of two or more. Further, a reaction mixture containing a dicarboxylic acid having 6 carbon atoms, such as adipic acid, oxycaproic acid, and caprolactone, obtained by oxidizing cyclohexane, can also be used as a raw material. Among them, it is preferable to use an aliphatic or aromatic dicarboxylic acid having 4 to 10 carbon atoms as a raw material.

As the solid catalyst, any one known to have catalytic activity in the reaction for producing the corresponding glycol by hydrogenating the starting dicarboxylic acid can be used. Usually, Group 8 metals of the periodic table, for example, Ru, P
A solid catalyst containing t, Pd, Rh, Ni or the like as an active component is used. In particular, a catalyst containing Ru and Sn is preferably used. Although the catalyst can be used in an unsupported type,
The active ingredient is preferably used as a supported catalyst in which the active ingredient is supported on a porous carrier.

The method for preparing the unsupported catalyst is as follows.
For example, Journal of Catalyst 1
21 (1) 165 ('90), a method using a reducing agent, a method using a coprecipitation method, and the like. As the porous carrier used for preparing the supported catalyst, conventional porous carriers such as activated carbon, diatomaceous earth, alumina, silica, titania, and zirconia can be used alone or in combination of two or more. Among them, activated carbon is particularly preferred. As a method for supporting the metal component on the carrier, any method commonly used for preparing a supported catalyst such as an immersion method, an ion exchange method, and a sol-gel method can be applied. Among them, the immersion method is adopted as a particularly simple method. When the immersion method is used, for example, a metal compound to be supported is dissolved in a solvent in which the compound can be dissolved, for example, water to form a solution of the metal compound, and this solution is immersed in a separately prepared porous carrier to form a carrier. The catalyst component is supported. As the metal compound, a mineral acid salt such as nitric acid, sulfuric acid, and hydrochloric acid is generally used, but an organic acid salt such as acetic acid, a hydroxide,
Oxides or generally known organometallic compounds or complex salts can also be used.

The order in which the metal components are supported on the carrier is arbitrary. The metal components can be supported simultaneously, all the components can be supported individually one by one, or a plurality of the components can be combined. It may be carried several times. After the metal component solution is immersed and carried (when immersed and carried a plurality of times, each time), drying is performed. Drying is performed at a temperature of 200 ° C. or lower under reduced pressure or while passing a dry gas such as air or an inert gas. After that, firing and reduction are performed as necessary. When performing a baking treatment, usually 100 to
This is performed in a temperature range of 600 ° C. while passing an inert gas such as air or nitrogen. In the case of performing the reduction treatment, a known liquid-phase reduction method and a known gas-phase reduction method are employed. In the case of the gas-phase reduction method, a temperature range of usually 100 to 600 ° C., preferably 20 ° C.
A temperature range of 0-500C is selected.

As the reducing gas, hydrogen, hydrogen diluted with an inert gas, methanol or the like is appropriately used. The loading amount of each metal component is in the range of 0.5 to 50% by weight, preferably 1 to 20% by weight, based on the carrier as the metal. The reaction system of the hydrogenation reaction may be either a liquid phase suspension reaction or a fixed bed reaction, and if necessary, the reaction zone may be divided into multiple stages. The reaction is carried out in an aqueous medium,
That is, the reaction is performed in water or an aqueous solution containing a water-soluble organic solvent. In this reaction, water is generated together with the alcohol corresponding to the raw material, so that water is preferably used as the solvent. The reaction is usually performed in a continuous mode.

In the present invention, when hydrogenating a dicarboxylic acid or an acid anhydride thereof in an aqueous medium in the presence of a solid catalyst, the reaction is carried out at 270 ° C. or lower, and when the temperature in the reaction zone is 160 ° C. or higher, Where the relationship between the temperature T (° C.) and the concentration C (% by weight) of the dicarboxylic acid or its acid anhydride satisfies the following formula (1), the reaction device whose liquid contact surface is made of a nickel-based alloy is used. By using it, the reaction can be stably performed over a long period of time.

[0014]

C> 2000 / (T-100) (1)

In the hydrogenation of a dicarboxylic acid using a solid catalyst, generally, the higher the reaction temperature and the higher the concentration of the dicarboxylic acid solution used for the reaction, the more the catalyst is deactivated. According to the study of the present inventors, the cause of the catalyst deactivation is that stainless steel, which is commonly used as a constituent material of the reactor, is corroded, and the eluted material poisons the catalyst. In the present invention, poisoning of the catalyst by the eluted material can be avoided by configuring the liquid-contacting portion of the portion where corrosion is likely to occur with a nickel-based alloy. Note that a nickel-based alloy is an alloy containing 45% by weight or more of nickel, such as a nickel-molybdenum alloy known as Hastelloy, a nickel-molybdenum-chromium alloy, and a nickel-copper alloy known as Monel steel. Is mentioned. Since a nickel-based alloy is expensive, in a preferred embodiment of the present invention, the relationship between the temperature T (° C.) and the concentration C (% by weight) of dicarboxylic acid or its acid anhydride is defined by the following formula (2): The liquid contact part is made of a nickel-based alloy.

[0016]

C> 3000 / (T-100) (2)

Even if the liquid contact portion is made of a nickel-based alloy, if the concentration of dicarboxylic acid or its acid anhydride is high, corrosion tends to occur.
(% By weight) and the temperature T (° C.) are preferably in a range defined by the following equation (3). In the present invention, the concentration of the acid anhydride is calculated in terms of hydrated dicarboxylic acid.

[0018]

C <6000 / (T-100) (3)

In the reaction zone, the relationship between the temperature and the dicarboxylic acid or its anhydride is not defined by the formula (1) or (2), for example, the reaction progresses to a considerable extent in the reaction zone. The dicarboxylic acid concentration has decreased,
A material other than a nickel-based alloy may be used. In the present invention, the reaction is carried out at a temperature of 270 ° C or lower, preferably 250 ° C or lower. If the reaction temperature is higher than this, corrosion will occur even if a nickel-based alloy is used. If the reaction temperature is lower than 160 ° C., the reaction rate of a normal hydrogenation catalyst is considerably reduced, which is not preferable. The reaction is preferably performed at 170 ° C. or higher. Further, in such a low temperature region, corrosion does not occur so much even when stainless steel is used, so that it is not necessary to use an expensive nickel-based alloy.

As reaction conditions other than the temperature, the reaction pressure is usually 5 to 30 MPa, 8 to 20 MPa, especially 10
-15 MPa is preferred. The reaction time is usually set at 0.1 as the liquid hourly space velocity (LHSV) of the supplied dicarboxylic acid solution.
¹ to 10 hr ^-1 , but 0.5 to 3 hr ^-1 , especially 1 to 10 hr ^-1
It is preferably 2 hr ^-1 . From the reaction product liquid flowing out of the reaction zone, glycol produced by distillation or other conventional separation means can be recovered. Unreacted raw materials and reaction intermediates can be reused as raw materials.

[0021]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples. Example 1 A fixed bed reactor made of a nickel-molybdenum alloy containing an inner diameter of 25 mm and a length of 1 m and made of nickel and containing 51% by weight of nickel was prepared according to the method described in the catalyst preparation example of JP-A-10-306047. % Ru-3% Pt-7% Sn / 94 g of activated carbon catalyst was charged. 30% by weight of 1,4-
The cyclohexanedicarboxylic acid aqueous solution was supplied by a plunger pump at a supply rate of 250 g / hour in a downflow manner. At the same time, hydrogen gas was supplied in a down flow at a supply rate of 100 NL / Hr. The reactor was heated by an electric heater, and the temperature of the reaction section was controlled to 250 ° C. The reaction pressure was maintained at 12 MPa by a pressure control valve of a hydrogen gas cylinder. The reactor effluent was withdrawn via a high pressure separator and a low pressure separator. The samples at 10 hours and 300 hours after the start of the reaction were analyzed, and the carboxyl group conversion and 1,4-cyclohexanedimethanol yield were determined. Table 1 shows the results.
Shown in After reacting for 300 hours, the reactor was opened and the state of corrosion of the inner wall of the reactor was observed, but no corrosion was found.

Comparative Example 1 A hydrogenation reaction was carried out in the same manner as in Example 1 except that a reactor made of SUS316L was used. Table 1 shows the results. When the inner wall of the reactor was observed after the reaction for 300 hours, corrosion was observed at the upper part of the reactor.

[0023]

[Table 1]

As is clear from Table 1, when a reactor having a liquid contact surface made of a nickel-based alloy is used, the reaction can be carried out for a long period of time without lowering the catalytic activity.

Continued on the front page (72) Inventor Atsushi Kayo 3-10 Ushidori, Kurashiki-shi, Okayama Prefecture Inside Mizushima Plant, Mitsubishi Chemical Corporation (72) Inventor Masazumi Miyazawa 3-10, Utsudori, Kurashiki-shi, Okayama Prefecture F-term (reference) 4H006 AA02 AC41 BA11 BA17 BA21 BA23 BA24 BA25 BA26 BB14 BB15 BB31 BB47 BC10 BC38 BD83 BE20 FC52 FE11 FE13 FG28 FG29 4H039 CA60 CB40

Claims (7)

[Claims] 1. A method for producing a glycol by hydrogenating a dicarboxylic acid or an acid anhydride thereof in an aqueous medium in the presence of a solid catalyst, wherein the reaction is carried out at 270 ° C. or lower, and the temperature in the reaction zone is lower than 270 ° C. The part where the relationship between the temperature and the concentration of dicarboxylic acid or its anhydride at 160 ° C. or more satisfies the following formula (1) is characterized by using a reaction apparatus whose liquid contact surface is made of a nickel-based alloy. Method. C> 2000 / (T-100) (1) (wherein T is the reaction temperature (° C.) and C is the concentration (% by weight) of dicarboxylic acid or its anhydride. .) 2. When the temperature in the reaction zone is 160 ° C. or higher,
2. A reactor in which the relationship between the temperature and the concentration of dicarboxylic acid or its acid anhydride satisfies the following formula (2) is to use a reactor whose liquid contact surface is made of a nickel-based alloy. The described method. C> 3000 / (T-100) (2) (wherein T is the reaction temperature (° C.) and C is the concentration (% by weight) of dicarboxylic acid or its anhydride. .) 3. The concentration of dicarboxylic acid or acid anhydride in a part of the reaction zone where the reaction temperature is 160 ° C. or higher and the liquid contact surface is made of a nickel-based alloy is calculated by the following formula (3). 3. The method according to claim 1, wherein the range is defined. C <6000 / (T-100) (3) (where T is the reaction temperature (° C.) and C is the concentration (% by weight) of dicarboxylic acid or its anhydride. .) 4. The method according to claim 1, wherein the temperature of the reaction zone in which the liquid contact part is made of a nickel-based alloy is 170 to 250 ° C. 5. The method according to claim 1, wherein the solid catalyst contains a metal belonging to Group 8 of the periodic table. 6. The method according to claim 1, wherein the solid catalyst contains ruthenium. 7. The method according to claim 1, wherein the dicarboxylic acid or the acid anhydride thereof is an aliphatic or aromatic dicarboxylic acid having 4 to 10 carbon atoms or an acid anhydride thereof. the method of.