KR20110117301A - Method for preparing nanometer sized cu based catalyst - Google Patents

Abstract

At least one second component precursor selected from the group consisting of a copper precursor, a first component, a transition metal, an alkaline earth metal, and a group IIIb component and 1 selected from the group consisting of alumina, silica, silica-alumina, magnesia, titania, zirconia, and carbon Dissolving at least three third component precursors in an aqueous solution and then stirring; Precipitating the mixed solution obtained in the stirring to the catalyst precursor precipitate using Na ₂ CO ₃ and NaOH: and the method for producing a nanometer-sized copper-based catalyst comprising the step of washing and filtering the formed catalyst precursor precipitate Is initiated.

Description

Method for preparing nanometer sized copper based catalyst

The present invention relates to a method for producing a copper-based catalyst having a nanometer size, and more particularly to a method for producing a catalyst for controlling the size of the copper particles to a size of several tens of nanometers or less using a specific precipitant.

When copper is used as a catalyst it is usually active in the hydrogenation-dehydrogenation reaction. Copper metals that dissociate and adsorb hydrogen molecules to be activated in an atomic state and precious metals such as platinum, palladium, and rhenium are possible as active materials for the hydrogenation reaction. The active material of the hydrogenation reaction has a problem in that if the adsorption strength of hydrogen is too strong, the hydrocracking reaction proceeds, and even the carbon-carbon bonds of the hydrocarbons are broken and become hydrogenated. Therefore, it is necessary for hydrogen to be adsorbed at an appropriate strength.

Copper-based catalysts are applied to hydrogenation or dehydrogenation in a region with a relatively low temperature range (200 to 400 ° C). In particular, copper-based catalysts include hydrogenation reactions for the synthesis of alcohols from carboxylic acids and water-gas shift reactions for the synthesis of carbon monoxide and hydrogen from hydrocarbons and water or carbon and water, methanol to produce hydrogen from methanol. In contrast to methanol reforming, CO ₂ hydrogenation, which synthesizes methanol from hydrogen and carbon dioxide, hydrogen-dechlorination to remove chlorine from chlorine-containing hydrocarbons, and 1,4 butanedi It is known to exhibit excellent properties for applications in the production of gamma butyrolactane from gamma (1,4-BDO).

Various methods are known as a method for producing a copper catalyst. Korean Unexamined Patent Publication No. 2010-0006249 discloses a heterogeneous copper nanocatalyst and a manufacturing method thereof, and discloses a heterogeneous nanocatalyst in which copper nanoparticles are immobilized on a boehmite support and its use.

Korean Patent Publication No. 2007-0028102 discloses a method for preparing a copper-manganese oxide catalyst of nanoparticles, in which manganese nitrate hydrate and copper nitrate hydrate are dissolved in distilled water; Dissolving urea in the solution; Putting the carrier together in the solution and stirring under a neutral atmosphere; And drying, pulverizing and calcining the agitate.

However, to date, a method of efficiently preparing a nanometer-sized copper-based catalyst is still insufficient.

One aspect of the present invention is a copper precursor of the first component, transition metal, alkaline earth metal, at least one second component precursor selected from the group consisting of Group IIIb components and alumina, silica, silica-alumina, magnesia, titania, zirconia, carbon Dissolving at least one third component precursor selected from the group consisting of an aqueous solution and then stirring the solution; Precipitating the mixed solution obtained by the stirring to the catalyst precursor precipitate using Na ₂ CO ₃ and NaOH: and washing and filtering the catalyst precursor precipitate formed To provide.

Another aspect of the present invention is to provide a nanometer sized copper-based catalyst prepared by the production method of the present invention.

Another aspect of the present invention is to provide a nanometer sized copper-based catalyst used in the hydrogenation reaction.

However, technical problems to be achieved by the present invention are not limited to the above-mentioned problems, and other technical problems will be clearly understood by the general technicians from the following description.

According to one aspect of the invention, the at least one second component precursor selected from the group consisting of a copper precursor, a first component, a transition metal, an alkaline earth metal, a group IIIb component and alumina, silica, silica-alumina, magnesia, titania, zirconia Dissolving at least one third component precursor selected from the group consisting of carbon in an aqueous solution and then stirring the solution; Precipitating the mixed solution obtained by the stirring to the catalyst precursor precipitate using Na ₂ CO ₃ and NaOH: and washing and filtering the catalyst precursor precipitate formed to provide.

According to another aspect of the present invention, there is provided a nanometer sized copper-based catalyst prepared by the production method of the present invention.

According to another aspect of the present invention, there is provided a nanometer-sized copper-based catalyst prepared by the production method of the present invention used for the hydrogenation reaction.

Copper-based catalyst production method of the present invention is a copper, transition metal, alkaline earth metal, group IIIb component, alumina, silica, silica-alumina, magnesia, titania, zirconia, carbon components, the content between these components, the type of precipitant and pH at coprecipitation The nanometer sized copper-based catalyst can be prepared.

1 shows hydrogen reduction characteristics of a copper-based catalyst having different ratios of copper, zinc and alumina.
Figure 2 shows the reaction results in the direct hydrogenation of butyric acid of the catalyst with a different composition of the copper-based catalyst of the present invention.

Hereinafter, the present invention will be described in more detail.

Catalyst preparation method according to an embodiment of the present invention, the first component of the copper precursor, transition metal, alkaline earth metal, at least one second component precursor selected from the group consisting of Group IIIb components and alumina, silica, silica-alumina, Dissolving at least one third component precursor selected from the group consisting of magnesia, titania, zirconia and carbon in an aqueous solution, followed by stirring; Precipitating the mixed solution obtained in the stirring to the catalyst precursor precipitate using Na ₂ CO ₃ and NaOH: and washing and filtering the formed catalyst precursor precipitate.

Specific terms used throughout the description and claims of the specification are defined as follows.

“Copper-based catalyst” here means that copper acts as the main catalyst (catalyst). Even if it is a copper-based catalyst, the main catalyst component, copper, does not necessarily have to be more than other components in the total catalyst.

“Nanometer size” refers to particle size calculation through chemical adsorption-desorption of nitrous oxide (N ₂ O) gas and chemical adsorption-desorption of activated carbon monoxide or copper peaks of XRD (X-ray diffraction patterns). Refers to those measured from 1 nanometer to several hundred nanometers.

As used herein, “copper precursor” refers to a copper salt, which may be present in the copper or copper oxide state after firing.

In addition, “second component precursor” herein refers to salts of transition metals, alkaline earth metals, group III components or mixtures thereof, and may be present in the transition metal, alkaline earth metal, group III components or oxides thereof after firing. have.

As the first component constituting the copper-based catalyst component of the present invention, the copper precursor may include salts such as nitrate, acetate salt and chlorine salt. Copper nitrate hydrate is a copper nitrate (Cu (NO3) 2.nH2O) hydrate, which is trihydrate, hexahydrate, hexahydrate, etc., and is soluble in water and ethanol.

As the second component constituting the copper-based catalyst component of the present invention, the transition metal, alkaline earth metal, or group IIIb component is active in itself as a material mixed with the copper catalyst, but is less active than copper. As a copper-based catalyst component, the transition metal is Zn. Co, Ni, Cr, Fe, Mo, Nb, Mn, Pt, Pd, Rh, Ru, and alkaline earth metals are preferably Mg, Ca, Sr, Ba, or IIIb group Ga.

The content of the transition metal, alkaline earth metal, and group IIIb components constituting the copper catalyst need not necessarily be used in a smaller amount than copper, and may also be used in a larger amount, and preferably a copper to second component ratio. Can be used at 1: 0.4-3.5 as molar ratio.

As the third component constituting the copper-based catalyst component of the present invention, alumina, silica, silica-alumina, magnesia, titania, zirconia, carbon or a mixture thereof can be used. These components themselves do not have activity, but by adding a small amount in the preparation of the catalyst serves to improve the activity and selectivity, stability of the main catalyst and to support the catalyst. The content of the component is not particularly limited.

In the case of conventional copper-based catalysts, a lot of copper and zinc are used. In the case of such a CuZn catalyst, Cu size, specific surface area and dispersion degree are poor.

However, the inventors of the present application have found that when alumina or the like is used for the CuZn catalyst, the dispersion degree of Cu is increased, and Cu can be reduced at a low temperature. For example, when Al was added in the production of CuZn, it was found that the catalyst without Al was not sufficiently reduced to the Cu state of the metal at the time of reduction, and large Cu particles were formed.

In addition, the inventors of the present application are important because the particle size of the copper-based catalyst determines the efficiency of the hydrogenation reaction, and the second component and alumina, silica, silica-alumina of copper and transition metals, alkaline earth metals, group IIIb components or mixtures thereof When using the third component of magnesia, titania, zirconia, carbon or mixtures thereof, hydrogen reduction properties have been found to be effective, preferably from 20 nanometers to copper-based catalysts ranging from 1 nanometer to 50 nanometers in size. .

In addition, in the case of the copper-based catalyst, when the second component and the third component are used together, hydrogen reduction properties are good, and the molar ratio of copper to the second component is reduced at a lower temperature when the copper metal content is low, thereby hydrogenating. It was found that the efficiency can be increased.

Therefore, the copper-based catalyst particles can control the hydrogen reduction degree of the copper-based catalyst by adjusting the component ratio of copper and the second component.

In the method for preparing a catalyst according to an embodiment of the present invention, the first step may include one or more second component precursors and alumina selected from the group consisting of a first component precursor, a transition metal, an alkaline earth metal, and a Group IIIb component of the copper precursor, One or more third component precursors selected from the group consisting of silica, silica-alumina, magnesia, titania, zirconia, and carbon are dissolved in an aqueous solution, followed by stirring to obtain a mixed solution. Aqueous solutions include but are not limited to pure water. As mentioned above, the size of the copper-based catalyst affects the hydrogenation efficiency, and the catalyst size depends on the molar ratio of copper to the second component.

In the second step, the mixed solution obtained in the first step is precipitated into the catalyst precursor precipitate using a precipitant.

The use of Na ₂ CO ₃ as precipitant is followed by precipitation of the catalyst precursor precipitate with NaOH. In this case, it is possible to obtain copper metal particles having a smaller size than when only Na ₂ CO ₃ is used as the precipitant or when only NaOH is used.

This is because when NaOH is used as a precipitant, the copper and the precursor of the second component and the precursor of the third component are rapidly precipitated and the metal particles are mixed unevenly. On the other hand, when using NH3 aqueous solution as a precipitant, the pH is not kept constant during the coprecipitation and aging process. Therefore, during the catalyst preparation process, the copper and the precursor of the second component and the precursor of the third component are non-uniformly formed, and due to the pH change, the copper particle size may not be formed as small as the desired size.

However, by gradually increasing the pH using Na ₂ CO ₃ and then increasing the pH using NaOH, metal particles are mixed unevenly by preventing the sudden precipitation of copper, the second component and the third component. While preventing the pH is kept constant to obtain a copper-based catalyst of uniform nanoparticle size.

In the precipitation step, the pH is preferably 5.0 to 11.0.

The pH of the initial mixed catalyst precursor in a state where the copper precursor, the precursor of the second component, and the precursor of the third component is dissolved in the aqueous solution is 2-4, and when the alkali precipitant is gradually added, precipitation of the catalyst precursor starts from pH 5.

As the amount of alkali precipitant increases, the color of the metal mixture becomes darker, and the nanometer sized copper catalyst precipitates up to pH 9. At higher pH, the precipitated metal is redissolved again in aqueous solution. Therefore, the pH of the coprecipitation in the precipitation step is 5.0 to 11.0, more preferably pH 6 to 9 range is preferred.

In the third step, the catalyst precursor precipitate is washed and then filtered to be neutral.

When the copper-based catalyst is used in the hydrogenation reaction, after obtaining the final metal catalyst in the third step, the prepared metal catalyst is dried and calcined to be converted into a metal oxide state.

According to one embodiment of the present invention, there is provided a nanometer sized copper-based catalyst prepared by the production method of the present invention, preferably a copper-based catalyst of 20 nanometers or less.

The nanometer-sized copper-based catalyst prepared according to the preparation method of an embodiment of the present invention may be used for hydrogenation or dehydrogenation.

The nanometer sized copper-based catalyst of the present invention is a water-gas shift reaction, methanol reforming to produce hydrogen from methanol, and carbon dioxide hydrogenation process to synthesize methanol from hydrogen and carbon dioxide (CO ₂ hydrogenation, hydro-dechlorination to remove chlorine from chlorine-containing hydrocarbons or gamma-butyrolactone from 1,4-butanediol (1,4-BDO) Can be used for the reaction.

As for the particle | grains of the copper metal used for the said hydrogenation reaction or dehydrogenation reaction, 20 nm or less is preferable.

For example, when butanol was prepared by directly hydrogenating butyric acid using a catalyst using zinc as the second component and alumina as the third component, the butyric acid conversion and butanol selectivity were linear as the molar ratio of copper in the copper metal decreased. It is increased, which is consistent with the tendency of the copper particles in the copper-based catalyst to become smaller, and the better the reduction in the low temperature range, the higher the activity of butyric acid direct hydrogenation. Butyric acid conversion and butanol yield of these copper-based catalysts can be seen that the best when the copper particle size of the copper-based catalyst of 20 nm or less, as can be seen through Table 1 and FIG.

Hereinafter, the catalyst production method of the present invention will be described in more detail through Examples and Comparative Examples.

Comparative example  One : CuZnO  Preparation of the catalyst

CuZn (Cu: Zn molar ratio = 8: 2, later referred to as CZ-82 catalyst) for the preparation of the catalyst 300 ml of ultrapure distilled water (resistance of 18 MΩ or more) in copper nitrate [Cu (NO ₃ ) ₂ · 3H ₂ O] 24.8 g and zinc nitrate [Zn (NO ₃ ) ₂ .6H ₂ O] 7.93 g were dissolved together and stirred for 1 hour.

The stirred catalyst precursor mixed solution exhibited a pH range of 1.0 to 3.0, and then slowly added 1.0 M Na ₂ CO ₃ to the catalyst precursor mixed solution at a rate of 1.0 cc / min until the pH was in the range of 4.0 to 5.0. Thereafter, the catalyst precursor was precipitated in an aqueous solution by dropping at a rate of 1.0 cc / min until a pH of 7.0 was obtained with a 1.0 M NaOH solution.

The precipitated metal mixture was stirred at 25 ^° C. for 24 hours and allowed to stand for 6 hours to allow sufficient phase separation of water and catalyst precursor. After that, the formed catalyst precursor precipitate was sufficiently washed with filtration to pH 7.0, Filtration gave the final metal catalyst. The prepared metal catalyst was sufficiently dried at 100 ^° C. for 24 hours and then calcined under a 450 ^° C. air flow for 3 hours to convert to a metal oxide state.

Example  One : CuZnAl  Preparation of the catalyst ( Al  Effect of addition)

Comparative Example 1 A CuZnAl (Cu: Zn: Al molar ratio = 8: 1: 1 catalyst was prepared as a CZA-811 catalyst) to examine the change in catalytic activity when Al was added to the CZ-82 catalyst. . The catalyst of copper nitrate in 300 ml deionized water of distilled water _{[Cu (NO 3) 2 ·} 3H 2 O] 24.8 g, zinc nitrate _{[Zn (NO 3) 2 ·} 6H 2 O] 3.96 g, and aluminum nitrate [Al (NO _{3) 2} · 6H ₂ O] 5.0 g were dissolved together and stirred for 1 hour. After stirring, 1.0 M Na ₂ CO ₃ was slowly added to the catalyst precursor mixture at a rate of 1.0 cc / min until it was in the range of pH 4.0 to 5.0, and then until pH 7.0 was reached with 1.0 M NaOH solution. The catalyst precursor was precipitated on the aqueous solution at a rate of 1.0 cc / min.

The precipitated metal was subjected to calcination for 3 hours under a flow of 450 ^° C. after washing, filtration and drying, as described in Comparative Example 1.

CuZnAl catalyst was prepared by fixing the amount of Alumina and changing the ratio of Cu and Zn in order to examine the activity of the catalyst according to the change of Cu / Zn molar ratio in the CuZnAl catalyst system.

Example  2 : Cu , Zn , Al of molar ratio Preparation of a catalyst at 7: 2: 1

To prepare a catalyst having a molar ratio of Cu, Zn, Al in CuZnAl of 7: 2: 1 (hereinafter, referred to as CZA-721), copper nitrate [Cu (NO ₃ ) ₂ .3H was added to 300 ml of ultrapure distilled water. ₂ O] 21.7 g, zinc nitrate [Zn (NO ₃ ) ₂ .6H ₂ O] 7.9 g, and aluminum nitrate [Al (NO ₃ ) ₂ .6H ₂ O] 5.0 g were dissolved together and stirred for 1 hour. A catalyst was prepared in the same manner as in Comparative Example 1.

Example  3: Cu , Zn , Al of molar ratio Preparation of catalysts with 6: 3: 1

To prepare a catalyst having a molar ratio of Cu, Zn, Al of CuZnAl in 6: 3: 1 (hereinafter, referred to as CZA-631), copper nitrate [Cu (NO ₃ ) ₂ .3H in 300 ml of ultrapure distilled water. ₂ O] 18.6 g, zinc nitrate [Zn (NO ₃ ) ₂ .6H ₂ O] 11.9 g, and aluminum nitrate [Al (NO ₃ ) ₂ .6H ₂ O] 5.0 g were dissolved together and stirred for 1 hour. A catalyst was prepared in the same manner as in Comparative Example 1.

Example  4: Cu , Zn , Al of molar ratio Preparation of a catalyst with a 5: 4: 1

To prepare a catalyst having a molar ratio of Cu, Zn, Al of CuZnAl of 5: 4: 1 (hereinafter, referred to as CZA-541), copper nitrate [Cu (NO ₃ ) ₂ .3H in 300 ml of ultrapure distilled water. ₂ O] 15.5 g, zinc nitrate [Zn (NO ₃ ) ₂ .6H ₂ O] 15.9 g, and aluminum nitrate [Al (NO ₃ ) ₂ .6H ₂ O] 5.0 g were dissolved together and stirred for 1 hour. A catalyst was prepared in the same manner as in Comparative Example 1.

Example  5: Cu , Zn , Al of molar ratio Preparation of catalysts with a 4: 5: 1

To prepare a catalyst having a molar ratio of Cu, Zn, Al of CuZnAl in 4: 5: 1 (hereinafter, referred to as CZA-451), copper nitrate [Cu (NO ₃ ) ₂ .3H in 300 ml of ultrapure distilled water. ₂ O] 12.4 g, zinc nitrate [(NO ₃ ) ₂ · 6H ₂ O] and 5.0 g of aluminum nitrate [Al (NO ₃ ) ₂ .6H ₂ O] were dissolved together and stirred for 1 hour. A catalyst was prepared in the same manner as in Example 1.

Example  6: with precipitant Na ₂ CO ₃ after use NaOH  use

In order to investigate the change of catalytic activity according to the type of precipitant used in precipitation in CuZnAl catalyst system, Na ₂ CO ₃ After use, NaOH was added and used as a precipitant, respectively, to prepare a catalyst. This catalyst is the catalyst corresponding to the component ratio CZA-631 in the CZA catalyst according to the Cu / Zn molar ratio in Example 3 described above. The precipitating agent is 1.0 were prepared with M concentration, ultra pure distilled water to 300 ml of copper nitrate _{[Cu (NO 3) 2 ·} 3H 2 O] 18.6 g, zinc nitrate _{[Zn (NO 3) 2 ·} 6H 2 O] 11.9 g each, And 5.0 g of aluminum nitrate [Al (NO ₃ ) ₂ .6H ₂ O] were dissolved together and stirred for 1 hour.

First, 1.0 M Na ₂ CO ₃ was slowly added at a rate of 1.0 cc / min until the pH was in the range of 4.0 to 5.0, and then 1.0 M NaOH solution was added at 1.0 cc / min until the pH was 7.0. The catalyst precursor was precipitated in aqueous solution by dropping at a rate of min. Since the process is the same as in Comparative Example 1.

Example  7: CZA -631 of catalyst Copulation pH 8. With zero  maintain

In Example 3, after using the precipitant Na ₂ CO ₃ NaOH co-precipitation was the same as in Example 3 except that the pH was adjusted to 8.0 instead of dropping at a rate of 1.0 cc / min until the pH is 7.0 Was carried out.

Example  8: CZA -631 of catalyst Copulation pH 9. With zero  maintain

After using the precipitant Na ₂ CO _{3 in} Example 3 was the same as in Example 3 except that the pH was adjusted to 9.0 instead of dropping the pH at a rate of 1.0 cc / min until the pH is 7.0 Was carried out.

Comparative example  2: precipitant NaOH  use

In Example 6, except that NaOH was added after using Na ₂ CO ₃ as a precipitant, the catalyst precursor was precipitated in an aqueous solution by dropping at a rate of 1.0 cc / min until pH 7.0 using NaOH as a precipitant. It carried out similarly to Example 6.

Comparative example  3: precipitant NH ₃  Use of aqueous solution

In Example 6, after using Na ₂ CO ₃ as a precipitant, the catalyst precursor was dropped at a rate of 1.0 cc / min until the pH was 7.0 using an aqueous solution of NH ₃ (28-30 wt%) as a precipitant instead of NaOH. Except that was precipitated in an aqueous solution was carried out in the same manner as in Example 6.

Experimental Example  One : Cu  Metal of catalyst Cu Particle size, Specific surface area  And dispersion

Cu particle size, specific surface area and dispersity of CuZn catalyst, CuZnAl-811, CuZnAl-721, CuZnAl-631, CuZnAl-541, CuZnAl-451 catalysts were measured at 90 ^° C after reduction of the Cu-based catalyst at 300 ^° C for 2 hours. After adsorbing N ₂ O gas under the condition of C, the amount of N ₂ desorbed after the temperature increase was measured.

Table 1 shows the Cu particle size, specific surface area and dispersion of the catalyst. Unlike the CuZnAl catalyst, the CuZn catalyst did not measure the size, specific surface area and dispersion of Cu. This is because Al increases the dispersion of Cu in the production of CuZnAl catalyst and serves to reduce Cu at low temperature. The catalyst containing Al did not sufficiently reduce to the Cu state of the metal at the time of reduction, and formed Cu particles large enough to exceed the measurement range.

As a result of examining the Cu particles according to the molar ratio of Cu and Zn with the Al content fixed, the particle size of Cu decreases linearly as the Cu content is relatively low, whereas the specific surface area and dispersion of Cu increase relatively. You can see the tendency to do it.

Unlike the catalyst composed of only Cu and Zn, the CZA catalyst has a Cu particle size of about 70 nm or less.The smaller the Cu / Zn molar ratio, the smaller the Cu particles. It was confirmed that the size is formed to about 20 nanometers or less.

Experimental Example  2 : Cu  Of catalyst Cu Of Zn ratio Hydrogen Reduction Characteristics

TPR (Temperature Programmed Reduction) analysis was performed to investigate the hydrogen reduction properties of the prepared CZ catalyst and CZA catalyst. The Cu catalyst was pretreated in an atmosphere of 50 cc / min rate He at 120 ^° C. for 1 hour. After cooling to room temperature, the Cu catalyst was heated up to 700 ^° C. under hydrogen atmosphere to measure the reduction of the catalyst. Figure 1 shows the hydrogen reduction characteristics of the CZ catalyst and CZA catalyst. Looking at the peak temperature position of the reduction peak, it was confirmed that the CZ catalyst is reduced at a higher temperature than the CZA catalyst.

In addition, the smaller the ratio of Cu / Zn in the CZA-based catalyst, the lower the CZA catalyst at a lower temperature. As mentioned in Example 1, the size of Cu metal particles decreases as the molar ratio of Cu / Zn decreases. Shows the same trend. As a result, the smaller the Cu metal particles, the lower the temperature at which the CZA catalyst is reduced, and the Cu particles can control the hydrogen reduction degree of the Cu metal by controlling the ratio of Cu and Zn.

Experimental Example  3: CZ  And Cu Of Zn  Different molar ratios CZA  Butyric Acid Direct Hydrogenation of Catalyst

The prepared catalyst was applied to a butyric acid direct hydrogenation reaction, and FIG. 2 shows a reaction result for butyric acid direct hydrogenation of a catalyst having a different composition of the copper-based catalyst of the present invention. The activity of the prepared catalyst was tested in a continuous flow reactor in which the catalyst was fixed. All catalysts were reduced pretreated for 2 hours under 20 cc / min of hydrogen and 400 cc / min of nitrogen at 300 ^° C., followed by 270 ^o C, under a hydrogen flow of 400 cc / min at 550 psi. In the catalytic reaction, feed was supplied into the reactor under the condition of WHSV = 1.2, and a separate preheating section existed at the inlet of the reactant so that butyric acid was not supplied in the liquid phase on the catalyst.

The CZ-82 catalyst without alumina had large metal particles, a small active area of the catalyst, low conversion of butyric acid, and rapid deactivation of catalyst performance. On the other hand, in the case of alumina-added catalysts, Cu particles were relatively small in size, and Cu had a high specific surface area, indicating high conversion of butyric acid and butanol selectivity. Alumina acts as a dispersant to increase the specific surface area of Cu metals. For CZA catalysts, butyric acid conversion and butanol selectivity increased linearly as the molar ratio decreased. It was confirmed that the lower the temperature range, the better the reduction in the butyric acid direct hydrogenation.

Both the CZA-541 catalyst and the CZA-451 catalyst exhibited superior characteristics compared to other CZA catalysts with different butyric acid conversions and butanol yields with Cu particle sizes of 20 nm or less. However, it was confirmed that the CZA-541 catalyst having a larger particle size but a higher Cu content than the CZA-451 catalyst having a relatively small particle size showed excellent characteristics in terms of durability.

In the direct hydrogenation of butyric acid, catalytic activity should enhance the activation of carbonyl groups in butyric acid. In addition to the metal Cu size, the high hydrogen reduction properties of Cu have an important effect on catalytic activity.

Accordingly, the CZA-541 catalyst has a higher Cu content than CZA-451, and is superior in durability to butyric acid in the structure of Cu, Zn, and Al. This example can be successful in reducing the size of Cu particles by lowering the Cu content and producing catalysts with a smaller Cu particle size down to several nanometers. However, the ability to activate carbonyl groups in butyric acid is reduced, resulting in direct hydrogenation of butyric acid. In the reaction, the phenomenon of deterioration of the catalyst performance was observed.

Experimental Example  4: Investigation of particle size change of copper catalyst according to the type of precipitant

In preparing the CZA-631 catalyst, the catalyst was prepared according to the type of precipitant, and used for the direct hydrogenation of butyric acid. The results are shown in Table 2. The catalytic reaction conditions were the same as in Experiment 3 except that WHSV = 1.2, and the Cu metal particles had a particle size of 100 nm in the case of 1.0 M NaOH precipitant and 1.0 M NH ₃ aqueous solution. Manufactured to size and above 1.0 M Na ₂ CO ₃ In the case of the catalyst prepared with NaOH as a precipitant, the particle size of the metal Cu was highly dispersed to 20 nm or less.

This is Cu, Zn. When the precursor of Al precipitates, it is judged to form a structure uniformly. On the other hand, when 1.0 M NaOH was used as a precipitant, Cu, Zn, and Al metals precipitated rapidly during the precipitation process, so that the metal particles were mixed unevenly. In addition, when the NH ₃ aqueous solution was used as a precipitant, the pH could not be kept constant during the coprecipitation and aging process.

In this manufacturing process, Cu particles could not be formed small due to non-uniform structure formation and pH change between Cu, Zn and Al. Due to these effects, NaOH and NH ₃ aqueous solutions were dissolved through butyric acid direct hydrogenation. When used as a precipitant it showed a low butanol yield.

Experimental Example  5: when settling pH Of particle size change of copper catalyst

Table 3 shows the results of preparing the CZA-631 catalyst prepared by varying the pH during precipitation. The prepared catalyst was carried out under the same reaction conditions as in Example 3, and it was confirmed that the catalyst precipitated under the pH = 9.0 condition exhibited high catalytic activity. The pH of the metal precursor during coprecipitation is known to have a significant effect on the formation of a certain structure by the mutual coupling of the metal components, and in the case of a catalyst prepared in the range of pH = 9.0 or more, the precipitated precursor is returned to the aqueous phase as the pH is increased. The dissociation phenomenon appeared and it was confirmed that the amount of the finally obtained catalyst is also relatively small.

Claims (8)

At least one second component precursor selected from the group consisting of a copper precursor, a first component, a transition metal, an alkaline earth metal, and a group IIIb component and 1 selected from the group consisting of alumina, silica, silica-alumina, magnesia, titania, zirconia, and carbon Dissolving at least three third component precursors in an aqueous solution and then stirring; Precipitating the mixed solution obtained by the stirring to the catalyst precursor precipitate using Na ₂ CO ₃ and NaOH: and washing and filtering the formed catalyst precursor precipitate. The nanometer sized copper of claim 1, wherein the ratio of the copper precursor and the second component precursor is in terms of copper to second component ratio, wherein the molar ratio of the second component is 0.4 to 3.5 based on copper. Method for producing a catalyst. The method of claim 1, wherein the transition metal is Zn, Co, Ni, Cr, Fe, Zn. Nanometer sized copper-based catalysts characterized in that Co, Ni, Cr, Fe, Mo, Nb, Mn, Pt, Pd, Rh, Ru, and alkaline earth metals are Mg, Ca, Sr, Ba, and IIIb group Ga Manufacturing method. The method of claim 1, wherein the pH of the precipitation step is a method for producing a nanometer sized copper-based catalyst, characterized in that 5.0 to 11.0. Nanometer size copper-based catalyst according to the method of claim 1. 6. The copper catalyst of claim 5, wherein the copper catalyst is 20 nm or less. The catalyst of claim 5 used in hydrogenation or dehydrogenation. The method of claim 7, wherein the hydrogenation or dehydrogenation reaction comprises a water-gas shift reaction, methanol reforming to produce hydrogen from methanol, and carbon dioxide hydrogenation to synthesize methanol from hydrogen and carbon dioxide. Process (CO ₂ hydrogenation), hydro-dechlorination to remove chlorine from chlorine-containing hydrocarbons or gamma-butyrolactone from 1,4-butanediol (1,4-BDO) The catalyst of claim 5, wherein the reaction is to generate a reaction product.

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