JP2009082889A - Alcohol production catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst used for producing alcohol by hydrogenating carboxylic acid, having a high catalytic activity and industrially satisfactory, and a method for producing alcohol.
[MEANS FOR SOLVING PROBLEMS] A catalyst for producing an alcohol by hydrogenating a carboxylic acid, comprising Co metal as an essential component and Zr, Y, La, Ce, Si, Al, Sc, V as a first promoter component. Alcohol containing at least one element selected, containing at least one element selected from Pt and Pd as the second promoter component, and having a Cubic phase of 20% or more of the Co metal crystal phase A catalyst for production, a method for producing the same, and a method for producing alcohol in which carboxylic acid is used as a raw material and hydrogenation is performed using the catalyst.
[Selection figure] None

Description

  The present invention relates to a catalyst for producing alcohol by hydrogenating carboxylic acid, a method for producing the catalyst, and a method for producing alcohol for hydrogenating carboxylic acid.

As a method for producing alcohol, a method of catalytic hydrogenation of a carboxylic acid ester is generally known and widely used industrially. On the other hand, attempts to obtain alcohol by catalytic hydrogenation of free carboxylic acid with a catalyst have been tried for a long time. For example, Patent Document 1 discloses a method for producing an alcohol using a Co catalyst containing a metal selected from Al, Zr, Mo, Y and the like and a metal selected from Cu, Pt, Pd and the like. . Patent Document 2 discloses a method for producing an alcohol using a Co catalyst in which Fe, Zn, P and the like are combined.
Japanese Patent Laid-Open No. 61-5036 JP-A-48-62708

  There have been attempts to improve the activity and durability of a desired reaction only with a combination of specific metals, but none of the catalysts that have been studied in the past are low in activity and yet industrially satisfactory. .

  An object of the present invention is to provide a catalyst used when hydrogenating a carboxylic acid to produce an alcohol, having a high catalytic activity and industrially satisfactory, and a method for producing the alcohol.

  The present inventors have found that the catalytic activity is improved when the Co metal has a specific promoter component and the Co metal, which is the main component of the catalyst, has a Cubic phase in a specific ratio as a crystal phase. The invention has been completed.

  That is, the present invention is a catalyst for producing an alcohol by hydrogenating a carboxylic acid, comprising Co metal as an essential component and Zr, Y, La, Ce, Si, Al, Sc, V as a first promoter component. Containing one or more elements selected from Pt and Pd as the second promoter component, and the Cubic phase of the Co metal crystal phase is 20% or more. Provided are a catalyst for alcohol production, a method for producing the same, and a method for producing alcohol, wherein carboxylic acid is used as a raw material and hydrogenation is performed using the catalyst.

  The catalyst of the present invention has a high catalytic activity and is industrially satisfactory. When the catalyst of the present invention is used, an alcohol can be produced in high yield from a carboxylic acid as a raw material. Is very advantageous.

[Catalyst for alcohol production]
The catalyst for alcohol production of the present invention comprises Co metal as an essential component, and one or more elements selected from Zr, Y, La, Ce, Si, Al, Sc, and V as a first promoter component, and a second promoter. It contains one or more elements selected from Pt and Pd as components, and the Cubic phase is 20% or more of the Co metal crystal phase.

  The Co metal is known to have two crystal phases, a Cubic phase and a Hexagonal phase, but the present inventors have found that the presence of the Cubic phase greatly contributes to the catalytic activity. The crystal phase of Co metal in the catalyst of the present invention is determined by measuring under the following conditions with an X-ray crystal diffraction (hereinafter abbreviated as XRD) apparatus. The Cubic phase and the Hexagonal phase are identified from the XRD peak pattern, and the respective crystal phase compositions are determined from the detected peak intensity.

<X-ray crystal diffraction measurement conditions>
Measured with Rigaku RINT2500VPC Radiation source: Cu Kα line, tube voltage: 40 kV, tube current: 120 mA, scanning speed: 10 deg / min,
Divergence slit: 1.0 deg, scattering slit: 1.0 deg, light receiving slit: 0.3 mm, scanning angle: 5-70 deg
(Source: POWDER DIFFRACTION FILE)
Co Cubic phase (cubic close-packed structure)
Lattice spacing d = 2.0467 (first peak / intensity 100), 1.7723 (second peak / relative intensity 40)
Lattice constant a = 3.5447Å
Co Hexagonal phase (hexagonal close-packed structure)
Lattice spacing d = 1.910 (first peak / intensity 100), 2.023 (second peak / relative intensity 60), 2.165 (third peak / relative intensity 20)
Lattice constants a, b = 2.507 mm, C = 4.070 mm.

  In the catalyst of the present invention, the proportion of the Cubic phase in the Co metal crystal phase calculated by the following formula (1) is 20% or more, preferably 50% or more, and more preferably 60% or more.

<Calculation method of ratio (%) of Cubic phase in Co metal crystal phase>
In the present invention, the proportion of the Cubic phase in the Co metal crystal phase was determined by the following formula (1) using the intensity ratio of the Cubic phase first peak (Ic) and the Hexagonal phase first peak (Ih).

  However, since the second peak of the Hexagonal phase overlaps the first peak of the Cubic phase, the first peak intensity (Ic) of the Cubic phase is the second peak of the Hexagonal phase from the peak intensity around d = 2.04 where the first peak of the Cubic phase appears. It was obtained by subtracting the strength of origin (determined as 0.6 times the first peak of the Hexagonal phase).

That is, the peak intensity in the vicinity of d = 1.91 is I _1.91 , the peak intensity in the vicinity of d = 2.04 is I _2.04 , the intensity of the first peak of the Hexagonal phase Ih = I _1.91 , the intensity of the first peak of the Cubic phase Ic = I _2.04 −0.6 _{XI 1.91} was determined, and the ratio (%) of the Cubic phase was calculated by the following formula (1).

    Cubic phase ratio [%] = 100 × Ic / (Ic + Ih) (1)

From the viewpoint of catalytic activity, Co in the catalyst of the present invention preferably has a reduction rate of 40% or more, more preferably 70% or more, and even more preferably 80% or more. Here, the reduction rate of Co was calculated as an actual weight reduction amount when the theoretical weight reduction amount of Co oxide (Co ₃ O ₄ ) in the catalyst to Co metal was 100.

  The first promoter component in the catalyst of the present invention contains one or more elements selected from Zr, Y, La, Ce, Si, Al, Sc, and V, and Zr, Y, La, and Ce are preferable. These elements may be in any chemical state such as metals, oxides and hydroxides. From the viewpoint of catalytic activity, the ratio of Co to the first promoter component is preferably at least 0.1 mole of the first promoter component and more preferably at least 1 mole relative to 100 moles of Co. Moreover, 100 mol or less is preferable and 25 mol or less is more preferable.

  The second promoter component in the catalyst of the present invention contains one or more elements selected from Pt and Pd, and Pd is preferable. These elements may be in any chemical state such as metals, oxides and hydroxides. By containing the second promoter component, the reduction can be promoted and the reduction temperature can be lowered. Thereby, a high specific surface area can be obtained and activity can further be improved.

  From the viewpoint of catalyst activity, the ratio of Co to the second promoter component is preferably 0.0001 mol or more, more preferably 0.01 mol or more, and more preferably 0.05 mol with respect to 100 mol of Co. The above is more preferable. Although there is no upper limit in particular, 10 mol or less is preferable.

  The catalyst of the present invention can include a support. Examples of the carrier include diatomaceous earth, alumina, silica, silica-alumina, magnesia, zirconia, titania, ceria, activated carbon, or a composite oxide thereof. By using the carrier, Co and the promoter component can be highly dispersed, and the activity can be improved. The amount of the carrier in the whole catalyst is preferably 80% by weight or less, and more preferably 50% by weight or less.

  The catalyst of the present invention can contain components for molding, such as a binder component and a lubricant.

[Method for producing catalyst]
The production method of the catalyst of the present invention is not particularly limited, but is generally prepared by the steps of preparation of catalyst precursor, drying / calcination, reduction, Co, Zr, Y, La, Ce, Si, Al, Sc, It is preferable to have a step of reducing the catalyst precursor containing one or more elements selected from V and one or more elements selected from Pt and Pd under a temperature condition of 300 to 800 ° C. in a hydrogen atmosphere. Furthermore, it is more preferable to have a step of forming and stabilizing an oxide film on the surface of the reduced catalyst after the step of further reducing treatment.

  As a method for preparing the catalyst precursor, a coprecipitation method, a physical mixing method, and an impregnation supporting method are preferably used.

  The coprecipitation method uses Co and one or more first promoter components selected from Zr, Y, La, Ce, Si, Al, Sc, and V, and one or more second promoters selected from Pt and Pd. In this method, a mixed aqueous solution of each metal salt composed of components and a precipitant are mixed.

  Any metal salt may be used as long as it is water-soluble, but in general, sulfate, nitrate, ammonium complex, acetate or chloride can be used.

  As the precipitating agent, an aqueous alkali solution such as ammonia, urea, ammonium carbonate, sodium hydrogen carbonate, sodium carbonate, sodium hydroxide, potassium hydroxide or the like is used.

  The physical mixing method includes Co and one or more first promoter components selected from Zr, Y, La, Ce, Si, Al, Sc, and V, and one or more second promoters selected from Pt and Pd. This is a method in which compounds such as oxides, hydroxides, carbonates, phosphates and nitrates of the respective components are sufficiently physically mixed.

  The impregnation support method is a method of precipitating or impregnating a metal compound as a promoter component on a Co compound. For example, in a slurry in which Co oxide is suspended, a precipitate obtained by mixing the above precipitant with an aqueous metal salt solution that can be a co-catalyst component other than Co is washed, dried, and calcined, or Co oxidation A method of impregnating and supporting a metal salt that can be a promoter component other than Co from an aqueous solution state is exemplified.

  The catalyst of the present invention can be supported on a known carrier. Examples of the carrier include carriers such as diatomaceous earth, alumina, silica, silica-alumina, magnesia, zirconia, titania, ceria, activated carbon, and composite oxides thereof.

  In the case of using a carrier, a coprecipitation method in which a metal salt and a precipitant are mixed in a slurry in which the carrier is suspended, or a method in which a metal that can be a catalyst component is impregnated simultaneously or sequentially on the carrier.

  Of these catalyst precursor preparation methods, the coprecipitation method or the impregnation support method is preferred.

  The catalyst precursor prepared by the above method is preferably dried at 30 to 120 ° C. for 1 to 24 hours, and then usually calcined at 300 to 800 ° C. for 2 to 10 hours. By this firing operation, Co becomes an oxide.

  Next, the catalyst precursor is reduced. The catalyst is activated by this reduction treatment. As the reducing agent, hydrogen, carbon monoxide, formaldehyde and the like can be used. When the gaseous reducing agent is used, it may be used alone or may be used by mixing with an inert gas such as nitrogen or water vapor. Among them, it is desirable to use hydrogen as the reducing agent.

  In the case of using hydrogen, the reduction treatment may use a gas phase system in which hydrogen gas is brought into contact with a dry catalyst precursor, or a liquid phase system in which the catalyst precursor is immersed in a liquid and hydrogen is circulated. May be. As such a liquid, a hydrocarbon such as liquid paraffin, an aliphatic alcohol or an aliphatic ester, or a carboxylic acid serving as a hydrogenation raw material can be used.

  When hydrogen is used as a reducing agent and is activated for reduction in a gas phase system, it is preferably carried out at 300 ° C. or higher, more preferably 400 ° C. or higher, more preferably 420 ° C. or higher, particularly preferably 450 ° C. under hydrogen flow. That's it. The hydrogen used may be 100%, or may be diluted with an inert gas. In order to prevent heat generation due to rapid reduction, a diluted one is preferable, a hydrogen concentration of 0.5 to 50 vol / vol% is more preferable, and a hydrogen concentration of 1 to 10 vol / vol% is still more preferable. Such reduction at a high temperature can increase the degree of reduction and increase the content of the Cubic phase. Since reduction at a high temperature may cause a decrease in specific surface area, it is preferably 800 ° C. or lower, and more preferably 600 ° C. or lower. The reduction is preferably processed until no hydrogen absorption is observed.

  If the reduction activated catalyst is left in the air as it is, it may react vigorously with oxygen in the air to generate heat. Therefore, it is preferable to form an oxide film on the surface of the reduction activated catalyst and stabilize it. This oxidation stabilization treatment is carried out at 0 to 200 ° C., preferably 20 to 100 ° C., more preferably 20 to 50 ° C. for 1 to 24 hours under the flow of an inert gas such as nitrogen containing 0.1 to 5% by volume of oxygen. Then, it is preferable in terms of handling that an oxide film is formed on the catalyst surface portion and stabilized.

[Method for producing alcohol]
The alcohol production method of the present invention is a method in which carboxylic acid is used as a raw material and hydrogenation is performed using the catalyst of the present invention.

The carboxylic acid used in the present invention may be either a monocarboxylic acid or a polycarboxylic acid. As monocarboxylic acid, aliphatic carboxylic acid, aromatic carboxylic acid, araliphatic carboxylic acid, and alicyclic carboxylic acid are used. As polycarboxylic acid, aliphatic dicarboxylic acid and aromatic dicarboxylic acid are used. Is done. Examples of the carboxylic acid include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, isostearic acid, benzoic acid, Examples include oxalic acid, tartaric acid, maleic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, and cyclohexanecarboxylic acid. These carboxylic acids may be free carboxylic acids or acid anhydrides. Moreover, you may have functional groups other than carboxyl groups, such as halogen groups, such as an amino group, an alkoxy group, and a chloro group, a phosphonic acid group, and a sulfonic acid group.
Moreover, the organic carboxylic acid contained in other compounds, such as methyl ester and fats and oils, can also be used as a raw material.

  The alcohol production method of the present invention can be carried out in either a suspension bed reaction system or a fixed bed reaction system. For example, when the suspension bed reaction method is employed, a powdered catalyst is used, and the following reaction conditions are selected. The reaction temperature is preferably 150 to 300 ° C. The reaction pressure is preferably 1 to 30 MPa, more preferably 5 to 30 MPa. The amount of the catalyst used is preferably 0.5 to 20% by weight, more preferably 1 to 10% by weight, based on the raw material carboxylic acid. The amount of the catalyst can be arbitrarily selected within a range in which a practical reaction rate can be obtained according to the reaction temperature or reaction pressure.

  In addition, when a fixed bed reaction method is employed, a catalyst formed for a proper purpose is used. The reaction temperature is preferably 150 to 300 ° C, more preferably 180 to 250 ° C. The reaction pressure is preferably 1 to 30 MPa, more preferably 5 to 30 MPa. Here, the liquid hourly space velocity (LHSV) is arbitrarily determined according to the reaction conditions. However, when productivity or reactivity is taken into consideration, a range of 0.2 to 5 [1 / hr] is desirable.

  Although it is possible to use a solvent for the reaction, it is desirable to carry out the reaction without a solvent in consideration of productivity. As the solvent, an alcohol, an ether such as dioxane, a hydrocarbon or the like that does not adversely influence the reaction is selected.

Example 1
(1) Preparation of catalyst precursor A mixed aqueous solution of cobalt nitrate, yttrium nitrate (n-hydrate) and palladium nitrate having an atomic ratio of cobalt to yttrium to palladium of 100: 5: 0.08 and an aqueous ammonium carbonate solution are stirred at room temperature. Mixed. The resulting precipitate was sufficiently washed with water and dried at 110 ° C. After drying, firing was performed at 600 ° C. for 4 hours to obtain a Co—Y—Pd oxide. The obtained calcined catalyst had an atomic ratio of Co / Y / Pd = 100 / 4.2 / 0.08.

(2) Activation of catalyst A calcined catalyst (oxide) placed on a calcining dish was set in an electric furnace capable of a reducing atmosphere. Hydrogen 4% [v / v] diluted with nitrogen was circulated and heated to 500 ° C. The reduction treatment was performed until no hydrogen absorption was observed. The reduction treatment time was 5 hours. Next, the system was purged with nitrogen and cooled to room temperature. Next, air diluted with nitrogen (oxygen concentration [1% v / v]) was circulated to stabilize the surface of the reduction catalyst. The oxidation stabilization treatment was performed until oxygen absorption was not observed. The Co reduction rate of the obtained catalyst was calculated as an actually measured weight reduction amount when the theoretical weight reduction amount of Co oxide (Co ₃ O ₄ ) in the catalyst to Co metal was taken as 100. Moreover, when the XRD analysis of the obtained catalyst was conducted, the peak pattern shown in FIG. 1 was obtained. From this peak pattern, the proportion of the Cubic phase in the Co metal crystal phase was determined. These results are shown in Table 1.

(3) Production of alcohol 3.75 g (weight in terms of oxide) of the obtained catalyst and 150 g of lauric acid were charged into a 500 ml autoclave and replaced with hydrogen, and then under a flow of 230 ° C./24.5 MPa / 900 rpm / hydrogen 5 L / min. Reacted for 40 minutes. After completion of the reaction, the autoclave was cooled and decompressed, and the product was recovered by filtering the reaction solution. The composition of the product was determined by the following gas chromatography (GC) analysis. Table 1 shows the composition of the produced alcohol and residual fatty acid after completion of the reaction.

<GC analysis method>
Take 1 drop of the reaction product in a 10 ml sample bottle, put trimethylsilyl (TMS) agent (TMSI-H / GL Science Co., Ltd.) in it, and process for about 5 minutes (40 ° C warming). The sample was diluted with 1.5 ml of hexane and filtered through a 0.2 μm membrane filter for GC analysis.

GC measurement conditions: HP-6890
Capillary column Ultra-AlloyUA ⁺ -1 (HT) 15m, film thickness 0.15μm
Temperature 60 ℃ (2 minutes) → 10 ℃ / min → 350 ℃
Split ratio 15, Inj temperature 300 ° C, Det temperature 350 ° C.

Example 2
(1) Preparation of catalyst precursor A mixed aqueous solution of cobalt nitrate and zirconium oxynitrate having an atomic ratio of cobalt to zirconium of 100: 5 and an aqueous ammonium carbonate solution were stirred and mixed at room temperature. The resulting precipitate was sufficiently washed with water and dried at 110 ° C. After drying, baking was performed at 600 ° C. for 4 hours to obtain a Co—Zr oxide. The obtained calcined catalyst had an atomic ratio of Co / Zr = 100 / 2.2.
Next, an aqueous palladium nitrate solution prepared so as to be 0.1% by weight as Pd was added to the obtained Co—Zr oxide, and thoroughly mixed to impregnate Pd. Furthermore, it was dried at 110 ° C. to obtain a palladium-supported Co—Zr oxide.

(2) Catalyst activation Catalyst reduction and oxidation stabilization were carried out in the same manner as in Example 1, (2). Table 1 shows the Co reduction rate of the obtained catalyst and the ratio of the Cubic phase in the Co metal crystal phase.

(3) Production of alcohol Using the obtained catalyst, an alcohol was produced in the same manner as in (1) of Example 1, and the composition of the product was similarly determined. Table 1 shows the composition of the produced alcohol and residual fatty acid after completion of the reaction.

Comparative Example 1
(1) Preparation of catalyst precursor Co-Y-Pd oxide was obtained in the same manner as in Example 1 (1).

(2) Activation of catalyst
A 500 ml autoclave was charged with a calcined catalyst (oxide) and lauryl alcohol, the inside of the system was replaced with hydrogen, the pressure was increased to 5 MPa, and the mixture was treated at 250 ° C. for 30 minutes. After cooling and depressurization, the catalyst cake was obtained by filtration. Table 1 shows the ratio of the Cubic phase in the Co metal crystal phase of this catalyst cake.

(3) Production of alcohol Using the obtained catalyst, an alcohol was produced in the same manner as in (1) of Example 1, and the composition of the product was similarly determined. Table 1 shows the composition of the produced alcohol and residual fatty acid after completion of the reaction.

2 is a peak pattern showing the XRD analysis result of the catalyst obtained in Example 1.

Claims (5)

  A catalyst for producing alcohol by hydrogenating carboxylic acid, comprising Co metal as an essential component and one kind selected from Zr, Y, La, Ce, Si, Al, Sc, and V as a first promoter component A catalyst for alcohol production containing the above elements, containing one or more elements selected from Pt and Pd as the second promoter component, and having a Cubic phase of 20% or more of the Co metal crystal phase.   The catalyst for alcohol production according to claim 1, wherein the reduction rate of Co contained in the catalyst is 40% or more.   A catalyst precursor containing Co, one or more elements selected from Zr, Y, La, Ce, Si, Al, Sc, and V, and one or more elements selected from Pt and Pd, in a hydrogen atmosphere. The manufacturing method of the catalyst for alcohol production of Claim 1 or 2 which has the process of carrying out the reduction process on 300-800 degreeC temperature conditions.   The method for producing a catalyst for alcohol production according to claim 3, further comprising a step of forming an oxide film on the surface of the reduced catalyst and stabilizing the step after the reduction treatment.   A method for producing an alcohol, wherein carboxylic acid is used as a raw material and hydrogenation is carried out using the catalyst according to claim 1 or 2.

Images