JP2001046873A - Hydrogenating catalyst and production of alcohols from carboxylic acids using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catalyst capable or producing alcohols from carboxylic acids with high activity and high selectivity by heating a catalyst precursor containing a metal selected from groups VII-XI metals to a specific temp. or higher in an inert gas and bringing the same into contact with a reducible gas to start the reduction treatment thereof. SOLUTION: A catalyst precursor containing at least one kind of a metal selected from groups VII-XI metals is heated to 70 deg.C or higher in an inert gas and brought into contact with a reducible gas to start reduction treatment to prepare a hydrogenating catalyst. Carboxylic acids are hydrogenated in a liquid phase in the presence of the catalyst to produce alcohols in a high yield. The metal is selected from the group consisting of ruthenium, rhodium, palladium, rhenium, platinum and cobalt. The metal as an active component is carried on a carrier such as graphite, or the like, to be used. As the reducible gas, hydrogen is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydrogenation catalyst and a method for producing alcohols from carboxylic acids using the same. In the present specification, carboxylic acids mean carboxylic acids and their derivatives such as carboxylic anhydrides and carboxylic esters. Carboxylic acid esters include oligomers and lactones which are esters of hydroxycarboxylic acids. Further, the alcohols are meant to include lactones, which are intermediates for hydrogenation of dicarboxylic acids to diols, and cyclic ethers, which are intramolecular dehydrates of diols, in addition to alcohols. Thus, lactones are in some cases raw carboxylic acids and in other cases product alcohols.

[0002]

2. Description of the Prior Art It is known to hydrogenate carboxylic acids to produce alcohols. Since the reaction performance of this reaction is largely controlled by the hydrogenation catalyst used, much effort has been put into improving the hydrogenation catalyst. For example, as a method for producing 1,4-butanediol from maleic acid, a method is known in which maleic acid is reacted with an alcohol to form a maleate ester, and this is hydrogenated at high pressure in the presence of a copper-based catalyst. However, this method is not advantageous for industrial practice, since the carboxylic acid must be esterified once and the hydrogenation reaction must be performed at a high pressure of, for example, 200 atm or more.

[0003] In addition, catalysts are known which enable hydrogenation of carboxylic acids directly without esterification. For example, JP-A-63-218636 and U.S. Pat.
No. 659,686 describes the production of tetrahydrofuran or γ-butyrolactone by reducing maleic acid in an aqueous solution using a palladium-rhenium catalyst supported on activated carbon. However, the former method has a low reaction substrate concentration, and the latter method requires a hydrogen pressure of 150 atm or more, and neither method is suitable for industrial implementation.

[0004] US Patent No. 4,827,001 describes a method for directly reducing maleic acid using ruthenium-iron oxide as a catalyst. However, this method is not satisfactory in the selectivity of 1,4-butanediol, tetrahydrofuran and γ-butyrolactone, which are the objective substances. JP-A-5-246915 discloses that in the hydrogenation reaction of carboxylic acids, a catalyst in which a noble metal of Group VIII is supported on a carrier made of porous carbon has high activity and excellent reaction results. And the coexistence of tin with the Group VIII noble metal improves the selectivity of the catalyst. JP-A-7-165644 discloses that a catalyst in which ruthenium, at least one of palladium and rhodium and tin are supported on a carrier such as activated carbon is effective for producing 1,4-butanediol and tetrahydrofuran from maleic anhydride. It is shown that

[0005]

However, according to the study of the present inventors, the reaction results obtained with these catalysts are not yet satisfactory for industrially carrying out the hydrogenation reaction of carboxylic acids. . Accordingly, an object of the present invention is to provide a catalyst which is highly active and can produce alcohols from carboxylic acids with high selectivity, and a method for producing alcohols using this catalyst.

[0006]

According to the present invention, a catalyst precursor containing at least one metal selected from metals of Groups 7 to 11 of the periodic table is heated to 70 ° C. or more in an inert gas. By heating, and in the presence of a catalyst produced by initiating a reduction treatment by contacting with a reducing gas in this state, carboxylic acids are hydrogenated in a liquid phase to produce alcohols in high yield. be able to.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The catalyst used in the present invention must contain at least one metal selected from metals of Groups 7 to 11 of the periodic table. Usually, at least one metal selected from the group consisting of ruthenium, rhodium, palladium, rhenium, platinum and cobalt is contained. Of these, rhenium is preferably contained, and particularly preferred is rhenium and platinum, or a catalyst further containing cobalt. The catalyst used in the present invention may contain other metals, if desired, in addition to the metals of Groups 7 to 11 of the periodic table. For example, when a diol is produced from a dicarboxylic acid such as maleic acid, the selectivity of the diol is generally improved by adding tin to the catalyst.

The catalyst used in the present invention contains the above-mentioned metals as active components, and these are usually used by being supported on a carrier.
As the carrier, commonly used inorganic porous substances such as silica, alumina, zirconia, titania, zeolite and mesoporous material, activated carbon, graphite and the like may be used. Among them, high surface area graphite (high surfacea)
It is preferred to use graphite called "rea graphite". Periodic table Nos. 7 to 11 in catalysts
The proportion of the group metal is usually at least 0.01% by weight or more, and if the proportion of the active ingredient is smaller than this, sufficient performance as a catalyst will not be exhibited. The upper limit is 50 for economic reasons
% By weight. The preferred range is 0.1 to 30% by weight, especially 0.5 to 20% by weight.

The support of the metal component on the carrier may be carried out according to a conventional method for preparing a catalyst. The most common method is an impregnation method in which a compound of a metal component is dissolved in an appropriate solvent to form a solution, and the solution is impregnated into a carrier. As the compound of the metal component,
Usually, inorganic acid salts such as metal nitrates, sulfates and hydrochlorides or organic acid salts such as acetates are used. In addition, hydroxides, oxides, complex salts, carbonyl complexes and acetylacetonate salts are also used. And the like can also be used.

For example, when ruthenium is supported, ruthenium chloride, ruthenium nitrosyl nitrate, ruthenium acetate, ruthenium hydroxide, ruthenium oxide, dicyclopentadienyl ruthenium, triruthenium dodecacarbonyl, ruthenium acetylacetonate and the like may be used. . In the case of platinum, chloroplatinic acid, sodium chloroplatinate, platinum oxide, tetraammineplatinium chloride, platinum acetylacetonate and the like may be used. For rhodium, rhodium chloride, rhodium nitrate, rhodium sulfate, rhodium acetate, rhodium hydroxide, rhodium oxide,
Hexachlororhodium sodium, hexachlororhodium ammonium, chloropentaamminerhodium, chlorohexamminerhodium, hexacyanorhodium potassium, trichlorotripyridinerhodium, chlorocyclooctadienylrhodium, tetrarhodium dodecacarbonyl, dicarbonylacetylacetonatotrodium and the like are used.

For palladium, palladium chloride, palladium nitrate, palladium sulfate, palladium acetate, palladium hydroxide, palladium oxide, palladium acetylacetonate, tetraamine palladium chloride, allyl (cyclopentadienyl) palladium, allyl (pentamethylcyclopentadiene) (Enyl) palladium, bis (allyl) palladium, or the like is used. For rhenium, use is made of rhenium heptaoxide, perrhenic acid, ammonium perrhenate, rhenium chloride or the like. For cobalt, cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt hydroxide, cobalt oxide, cobalt carbonate, bis (1,
5-cyclooctadienyl) cobalt, bis (cyclopentadienyl) cobalt, hexaamminecobalt chloride, cobalt acetylacetonate, tetracobalt dodecacarbonyl, cobalt stearate and the like are used. When tin is contained, tin chloride, alkyl tin, tin acetate, tin hydroxide, tin acetylacetonate, or the like may be used.

As a solvent for dissolving these metal component compounds, any solvent can be used as long as it has a dissolving power for these metal component compounds. From the viewpoints of safety and economy, it is preferable to use an aqueous solvent such as water, an aqueous acid solution, or an aqueous alkaline solution. In order to impregnate the carrier with the solution containing the metal component, a solution containing all the metal components to be supported may be prepared and impregnated into the carrier, or a solution may be prepared for each metal component. Alternatively, it may be supported by successive impregnation and drying. Also, impregnation may be carried out in a plurality of times without carrying the whole amount at once. In any case, when the impregnation is completed, the solvent is removed by drying. This can also be performed by any method such as heating drying, through-flow drying, and reduced-pressure drying that are commonly used in catalyst preparation. The drying temperature is usually from room temperature to about 300 ° C, preferably from 50 to 200 ° C. In the case of air drying, nitrogen, oxygen, argon, air or the like may be used. After drying, it may be further baked. The calcination is usually performed in a fixed bed flow system using nitrogen, oxygen, air, argon, or the like, but may be performed in a non-flow system. In the case of the circulation system, the space velocity of the gas is preferably set to 20 / hr or more.

In the present invention, the catalyst precursor thus prepared is subjected to a reduction treatment to obtain a catalyst. In the reduction treatment, first, the catalyst precursor is heated to 70 ° C. or higher in an inert gas. As the inert gas, argon, nitrogen, helium or the like may be used, and its flow rate is preferably 5 to 100 / hr in terms of space velocity with respect to the catalyst. Heating is preferably performed so that the temperature of the catalyst precursor is 100 ° C. or higher,
If the temperature is too high, the metal sinters, so that the heating is preferably performed so that the temperature of the catalyst precursor is 600 ° C. or lower, particularly 500 ° C. or lower.

When the temperature of the catalyst precursor reaches a predetermined value of 70 ° C. or more, the inert gas is switched to a reducing gas and the reduction treatment is performed in a gas phase. Hydrogen, methanol, carbon monoxide, nitrogen monoxide, etc. may be used as the reducing gas,
Among them, it is preferable to use hydrogen. These reducing gases may be diluted with an inert gas if desired. The reduction treatment is performed at 100 to 600 ° C, particularly 150 to 500 ° C.
It is preferable to carry out at a temperature of ° C. Processing time is usually 0.5 to 5
It is about 0 hours, but preferably 1 to 20 hours. The gas flow rate is preferably 5 to 100 / hr in terms of space velocity with respect to the catalyst.

In the present invention, the above-prepared hydrogenation catalyst is used to hydrogenate a carboxylic acid in a liquid phase to produce a corresponding alcohol. The carboxylic acids may be aliphatic, alicyclic or aromatic, but the present invention is particularly advantageous for producing diols from dicarboxylic acids or hydroxycarboxylic acids. Accordingly, one of the preferred aliphatic carboxylic acids is maleic acid and succinic acid, and their derivatives maleic anhydride, succinic anhydride,
Maleic acid ester, succinic acid ester, γ-butyrolactone, etc., and when these are used as raw materials, their hydrides, 1,4-butanediol, terahydrofuran and γ
-Butyrolactone and the like are obtained in high yield. Adipic acid, adipic acid ester, ε-hydroxycaproic acid and its ester ε-caprolactone and its oligomers are also one of the preferable raw materials. Is obtained.

As the alicyclic carboxylic acids, it is preferable to use cyclohexanedicarboxylic acid or an ester thereof, particularly 1,4-cyclohexanedicarboxylic acid or a lower alkyl ester thereof. As the aromatic dicarboxylic acids, it is preferable to use terephthalic acid or its lower alkyl ester.

The hydrogenation reaction of carboxylic acids is carried out in a liquid phase, usually in a solution. Water as the solvent; alcohols such as methanol, ethanol, octanol, dodecanol;
Ethers such as tetrahydrofuran, dioxane, and tetraethylene glycol dimethyl ether; and hydrocarbons such as hexane, cyclohexane, and decalin are used. When maleic acid is used as a raw material, it is preferable to use water, tetrahydrofuran or γ-butyrolactone as a solvent, and particularly preferable to use water as a solvent.
The concentration of the carboxylic acids in the solution is arbitrary, but is preferably high from the viewpoint of productivity. For example, when maleic acid is used as an aqueous solution for the hydrogenation reaction, 20 to 60% by weight
It is preferred to have a maleic acid concentration of the order of magnitude. The reaction system may be a batch reaction or a continuous reaction. Any reactor such as a fixed-bed reactor, a fluidized-bed reactor, and a suspension tank can be used. The temperature of the hydrogenation reaction is usually 50 to 300 ° C, preferably 80 to 250 ° C. Most preferred is 100-220 ° C. The reaction pressure is usually 0.1 to 30 MPa, preferably 1 to 25 MPa. Most preferred is 5 to 15 MPa.

[0018]

The present invention will be described more specifically with reference to the following examples. In the following,% means% by weight unless otherwise specified.

Preparation of catalyst A: 3% Re-3% Co-0.
Such that the 5% Pt / SiO _2, rhenium oxide (Kishida Chemical Co. product, Re ₂ O ₇₎ 0.195g, chloroplatinic acid (manufactured by Kishida Chemical Co. _{product, H 2 PtCl 6 · 6H 2} O) 0.
066 g and cobalt nitrate (a product of Kishida Chemical Co., Co.
(NO ₃₎ the ₂ · 6H ₂ O) _0.741g were dissolved in demineralized water 3g, silica solution (Fujishirishia's products, G-
12) 4.68 g were added. The water was removed by an evaporator, and then dried at 150 ° C. for 2 hours under flowing argon. Further, the mixture was heated to 300 ° C. while flowing argon, and argon was switched to hydrogen at this temperature. Subsequently, the mixture was heated to 400 ° C. under a hydrogen flow, and reduced at this temperature for 2 hours to obtain a catalyst A.

Preparation of catalyst B: 3% Re-3% Co-3%
Catalyst B was prepared in the same manner as in the preparation of Catalyst A, except that the amount of chloroplatinic acid was changed so as to obtain Pt / SiO _2.
I got

Preparation of Catalyst C: In the preparation of Catalyst A, the mixture was dried at 150 ° C. for 2 hours under flowing argon, cooled to room temperature, and replaced with hydrogen at room temperature. Subsequently, the mixture was heated to 400 ° C. under a hydrogen flow, and reduced at this temperature for 2 hours to obtain a catalyst C.

Preparation of catalyst D: The preparation of catalyst B was carried out in the same manner as in preparation of catalyst B, except that after drying at 150 ° C. for 2 hours under flowing argon, it was further heated to 400 ° C. under flowing argon, and argon was switched to hydrogen gas at this temperature. Catalyst D was obtained in the same manner as in the preparation of Catalyst B.

Preparation of Catalyst E: In the preparation of Catalyst C, the charged composition of the raw materials was changed to 3% Re-3% Co-3% Pt / Si
Catalyst E was obtained in the same manner as in the preparation of Catalyst C, except that O ₂ was used. Table 1 shows the compositions of catalysts A to E and the temperatures at the time of switching from argon to hydrogen in the reduction treatment.
It is shown in FIG.

[0024]

[Table 1]

Hydrogenation reaction of maleic anhydride; capacity 70 m
1.0 g of maleic anhydride, 9.0 g of water and 0.25 g of catalyst were placed in an autoclave of L
Pressurized. This is heated to 200 ° C. and stirred for 3 hours.
Allowed to react for hours. After completion of the reaction, the reaction solution was titrated with an alkali to calculate an acid conversion rate. The reaction solution was analyzed by gas chromatography to determine the amount of the product. Table 2 shows the results.

[0026]

[Table 2]

 ──────────────────────────────────────────────────続 き Continued on front page F-term (reference) 4G069 AA02 AA03 AA08 BA02A BA02B BC22A BC30A BC61A BC64A BC64B BC65A BC67A BC67B BC69A BC70A BC71A BC72A BC75A BC75B CB02 CB70 DA05 FA01 FA03 FA08 4H006 BA11BA24 BA17 BA24 BA81 BC14 BE20 FE11 FG28 4H039 CA60 CB40

Claims (11)

[Claims] 1. A catalyst precursor containing at least one metal selected from metals of Groups 7 to 11 of the periodic table is heated to 70 ° C. or higher in an inert gas, and in this state, a reducing gas and A hydrogenation catalyst prepared by contacting and starting a reduction treatment. 2. The hydrogenation catalyst according to claim 1, wherein the catalyst precursor contains at least one metal selected from the group consisting of ruthenium, rhodium, palladium, rhenium, platinum and cobalt. 3. The hydrogenation catalyst according to claim 1, wherein the catalyst precursor contains rhenium. 4. The hydrogenation catalyst according to claim 1, wherein the catalyst precursor contains rhenium, platinum and cobalt. 5. The hydrogenation catalyst according to claim 1, wherein the catalyst precursor contains tin. 6. The hydrogenation catalyst according to claim 1, wherein the reducing gas is hydrogen. 7. The hydrogenation catalyst according to claim 1, wherein the catalyst precursor contains a carrier. 8. A method for producing alcohols corresponding to carboxylic acids, wherein carboxylic acids are hydrogenated in a liquid phase in the presence of the hydrogenation catalyst according to any one of claims 1 to 7. 9. The method for producing alcohols according to claim 8, wherein the carboxylic acids are dicarboxylic acids or acid anhydrides thereof, and the produced alcohols are mainly diols. 10. The carboxylic acid is selected from the group consisting of maleic acid, maleic anhydride, succinic acid, succinic anhydride and γ-butyrolactone, and the alcohols formed are mainly 1,4-butanediol. 9. The method for producing alcohols according to claim 8, wherein: 11. The carboxylic acid is selected from the group consisting of maleic acid, maleic anhydride, succinic acid and succinic anhydride, and 80% by weight or more of the reaction product is 1,4.
9. The method for producing alcohols according to claim 8, which is -butanediol, tetrahydrofuran, and [gamma] -butyrolactone.