Catalyst for producing lactic acid by dehydrogenation of glycerol and manufacturing method thereof

Abstract

The present invention relates to a catalyst for dehydrogenation of glycerol and to a catalyst for dehydrogenation of glycerol, which includes a group 10 element on the periodic table as a catalytically active component and a composite metal oxide composed of zirconium (Zr) and cerium (Ce) as a catalyst support, and a manufacturing method thereof.

Description

Catalyst for producing lactic acid by dehydrogenation of glycerol and method for producing the same

[0001] The present invention relates to a catalyst for producing lactic acid by dehydrogenation of glycerol and a method for producing the same, and more particularly, to a catalyst capable of producing lactic acid with high efficiency by effectively dehydrogenating glycerol under basic conditions and a method for producing the same.

[0002] The development of new alternative energy sources for the future is emerging as a solution to the problems of resource depletion, global warming, and environmental pollution caused by the rapid use of fossil fuels. Among these, hydrogen, as a clean, pollution-free energy source, is increasingly becoming an essential new energy source for future fuel cell vehicles using hydrogen fuel cells, as well as for residential and industrial power generation.

[0003] Current commercialized hydrogen production technologies are based on catalytic chemical reforming of natural gas and dehydrogenation byproducts from petrochemical feedstocks. However, the development of high-value-added hydrogen production technologies utilizing alternative feedstocks is expected to become increasingly important in the future. In particular, biomass-based hydrogen production is considered an environmentally friendly and future-oriented value-added technology due to its characteristics. For example, the recent increase in biodiesel production and usage, coupled with the continued increase in low-grade glycerol byproducts (approximately 10% of the raw material), is being evaluated as having a limited impact on biodiesel competitiveness, along with a decline in its value due to oversupply.

[0004] Therefore, the method of converting these low-value-added glycerol by-products into hydrogen, a high-value-added clean fuel, is a major field of hydrogen production through biomass conversion, and research and development are currently being continuously conducted.

[0005] Glycerol dehydrogenation produces not only hydrogen but also high-value lactic acid (LA), making it a promising candidate for a hydrogen source. Accordingly, dehydration methods for producing hydrogen and lactate by dehydrogenating glycerol have been developed in recent decades. Since glycerol dehydrogenation is performed in a basic atmosphere due to the presence of metal hydroxide, there is a growing demand for catalysts that exhibit high dehydrogenation catalytic activity even in alkaline environments.

[0006] Meanwhile, as a prior art in the same technical field as the present invention, U.S. Patent Publication No. US 2015-0299082 A1 relates to a method for simultaneously producing lactic acid and propylene glycol from glycerol, and discloses a process for producing lactate by dehydrogenating glycerol using a copper (Cu)-containing dehydrogenation catalyst. In addition, U.S. Patent Publication No. US 2012-0253067 A1 discloses a technology regarding a catalyst containing copper, platinum, ruthenium, palladium, and rhodium as a process dehydrogenation catalyst for producing lactic acid from glycerol.

[0007] Prior art, including the above-mentioned prior art documents, discloses a technology for a catalyst that converts glycerol into lactate by dehydrogenation, but the stability is low even under basic conditions, and improvement in catalytic activity is needed.

[0008] [Prior Art Literature]

[0009] [Patent Document]

[0010] (Patent Document 1) United States Patent Publication No. US 2015-0299082 A1 (Published on October 22, 2015)

[0011] (Patent Document 2) United States Patent Publication No. US 2012-0253067 A1 (Published on October 4, 2012)

[0012] The present invention was created to solve the above-mentioned problem, and its purpose is to provide a catalyst capable of effectively dehydrogenating glycerol under basic conditions and a method for producing the same.

[0013] In order to solve the above problem, the present invention provides a glycerol dehydrogenation catalyst characterized in that an active metal containing at least one element of Group 10 of the periodic table is supported on a composite metal oxide containing zirconium (Zr) and cerium (Ce) as a catalyst support.

[0014] In one embodiment of the present invention, in the composite metal oxide, cerium may be 0.1 mol% to 20 mol% based on the total molar content of cerium (Ce) and zirconium (Zr), and the active metal may be 0.1 wt% to 20 wt% based on the total weight of the catalyst.

[0015] In addition, the present invention provides a method for producing a dehydrogenation catalyst for glycerol, comprising the steps of: (i) mixing an active metal precursor solution with a support solution while dropwise adding an active metal precursor solution to a dispersion solution in which a cerium-zirconium composite metal oxide support is dispersed; (ii) an aging step of stirring the mixed solution for a predetermined time after step (i); (iii) a separation step of separating the cerium-zirconium composite metal oxide support on which the active metal precursor is supported from the mixed solution after step (ii); and (iv) a step of calcining the cerium-zirconium composite metal oxide support on which the active metal precursor is supported after the separation step.

[0016] In one embodiment of the catalyst manufacturing method of the present invention, the step (iv) may further include a step of drying a cerium-zirconium composite metal oxide support on which an active metal precursor is supported.

[0017] In addition, the firing of the above step (iv) can be performed in the range of 400°C to 800°C, and a step of reducing the fired product after the above step (iv) at 200°C to 300°C may be further included.

[0018] In one embodiment of the catalyst manufacturing method of the present invention, the cerium-zirconium composite metal oxide support may be manufactured by including (a) a step of mixing a cerium source and a zirconium source; and (b) a step of calcining the mixture.

[0019] In addition, the present invention provides a method for dehydrogenating glycerol, characterized in that a solution containing glycerol and a hydroxide salt of an alkali metal or alkaline earth metal is brought into contact with a catalyst having at least one element of Group 10 of the periodic table supported on a composite metal oxide support of cerium and zirconium.

[0020] In the method for dehydrogenating glycerol of the present invention, the alkali metal or alkaline earth metal hydroxide salt may be used in an amount of 1.0 times or more relative to the molar content of glycerol, and cerium (Ce) in the composite metal oxide support may be 0.1 mol% to 20 mol% relative to the total molar content of cerium (Ce) and zirconium (Zr).

[0021] The present invention is a dehydrogenation catalyst for glycerol, which includes platinum (Pt) as a catalyst active component and a composite metal oxide containing cerium (Ce) and zirconium (Zr) as a catalyst support, thereby having the effect of stably performing a dehydrogenation reaction of glycerol under basic conditions.

[0022] Figure 1 illustrates the mechanism of glycerol dehydrogenation reaction.

[0023] Figure 2 shows the results of TEM, particle size analysis, and EDS analysis for the catalysts of Manufacturing Example 1 (a), Manufacturing Example 2 (b), and Manufacturing Example 6 (c).

[0024] Figure 3 shows the results of catalyst reuse experiments of Example 4 and Comparative Example 6.

[0025] Hereinafter, with reference to the attached drawings, a glycerol dehydrogenation catalyst and a method for producing the same will be described in detail so that a person having ordinary skill in the art to which the present invention pertains can easily practice the present invention.

[0026] When explaining in detail the principles of a preferred embodiment of the present invention, if it is determined that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof is omitted.

[0027] In addition, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and therefore, there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0028] The present invention relates to a glycerol dehydrogenation catalyst and a method for producing the same, and more particularly, to a dehydrogenation catalyst and a method for producing the same in a process of adding water and a metal hydroxide to glycerol and causing a dehydrogenation reaction to produce hydrogen and an organic acid metal salt in a dehydrogenated form of the glycerol.

[0029] Hereinafter, the glycerol dehydrogenation catalyst and its manufacturing method according to the present invention will be described in detail.

[0030] Figure 1 illustrates the dehydrogenation mechanism of glycerol. As illustrated in Figure 1, glycerol is converted to glyceraldehyde through dehydrogenation, which then passes through pyruvaldehyde to ultimately produce lactic acid. Among these, the dehydrogenation of glycerol to glyceraldehyde is a key step in this reaction, and it has been reported that high temperatures (over 550 K) are required in the hydrothermal process to convert glycerol into glyceraldehyde via glyceroxide ions as an intermediate. However, at high temperatures, side reactions such as the decomposition of pyruvaldehyde and lactic acid significantly progress, lowering the selectivity for the final lactic acid. To address this issue, the reaction can be performed at low temperatures under alkaline conditions. However, alkaline conditions can lead to reduced catalyst stability.

[0031] The glycerol dehydrogenation catalyst according to the present invention has the advantage of being stable under basic conditions while also having a high dehydrogenation efficiency of glycerol.

[0032] The catalyst of the present invention may include at least one of the elements of Group 10 of the periodic table as a catalytically active component, and includes a composite metal oxide composed of cerium (Ce) and zirconium (Zr) as a catalyst support. That is, the dehydrogenation catalyst of glycerol according to the present invention may include a cerium-zirconium composite metal oxide (Ce). x Zr 1-x O2) may be supported with an active metal containing at least one of the Group 10 elements, such as platinum (Pt) or palladium (Pd).

[0033] When cerium and zirconium exist as a composite metal oxide, stability is excellent even under basic conditions, and the conversion rate of glycerol and the selectivity for lactic acid are also increased.

[0034] In the catalyst of the present invention, the content of the active metal is preferably 20 wt% or less, and more preferably 0.1 wt% to 10 wt%, based on the total weight of the catalyst. When the content of the active metal is 0.1 wt% or more, the conversion rate of glycerol increases, but when it exceeds 20 wt%, even if the content of the active metal increases, the CC bond is broken, resulting in a decrease in selectivity, and thus the effect of increasing the activity relative to the content of the active metal is not significant, and thus may not be economical.

[0035] In addition, the glycerol dehydrogenation catalyst according to the present invention has a conversion rate of glycerol under basic conditions that varies depending on the mole ratio of cerium (Ce) and zirconium (Zr) in the composite metal oxide as the catalyst support. At this time, the glycerol dehydrogenation catalyst according to the present invention preferably has 0.1 mol% to 20 mol% of cerium (Ce) relative to the total molar content of cerium (Ce) and zirconium (Zr) in the catalyst support, and more preferably has 1 mol% to 10 mol%.

[0036] Regarding the total molar content of cerium and zirconium, when cerium is included in the range of 0.1 mol% to 20 mol%, the effect of increasing the conversion rate of glycerol and increasing stability under basic conditions is highly evident, but when cerium exceeds 20 mol%, the crystal structure of ZrO2 changes from a monoclinic to a tetragonal structure, which may cause a problem of reduced activity.

[0037] The method for producing a composite metal oxide catalyst support of cerium and zirconium according to the present invention may be characterized by including (a) a step of mixing a cerium source and a zirconium source; and (b) a step of calcining the mixture.

[0038] The above step (a) is a step of forming a complex of cerium and zirconium by mixing a cerium source and a zirconium source. The cerium source and zirconium source may be used without limitation as long as they are components containing cerium atoms and zirconium atoms, respectively. For example, the cerium source and zirconium source may be salts, complexes, etc. of cerium and zirconium, and specifically, may be at least one selected from nitrates, sulfates, phosphoric acids, halogen salts, alkoxide salts, oxynitrates, hydrates, acetate salts, alkyl salts, hydrates thereof, etc.

[0039] As described above, the content ratio of the zirconium source and the cerium source may be used in a range of 0.1 mol% to 20 mol% of cerium relative to the total molar content of zirconium and cerium.

[0040] Meanwhile, the mixing of the cerium source and the zirconium source can be applied without limitation as long as it is a method capable of forming a complex of cerium and zirconium, and examples thereof include a hydrothermal synthesis method, a co-precipitation method, an impregnation method, a mechanical mixing method, a deposition method, etc., and preferably, a hydrothermal synthesis method, a co-precipitation method, etc.

[0041] In one embodiment, among the above mixing methods, the hydrothermal synthesis may be performed by adding a base to a cerium source and a zirconium source to prepare a mixture solution of the cerium source, the zirconium source, and the base, and then performing the hydrothermal synthesis. At this time, the base may be at least one selected from urea, ammonia water, NaOH, an organic amine, etc., and urea may be preferably used. The base content is not particularly limited, but may be added so that the pH of the mixture solution in which the cerium precursor and the zirconium precursor are mixed is 8 or higher.

[0042] The above hydrothermal synthesis can be performed at a temperature of 100°C to 250°C for a predetermined period of time, for example, 10 to 30 hours. If the reaction temperature is lower than 100°C, the precursor may not react sufficiently due to the low reaction temperature, resulting in a low yield. If the reaction temperature exceeds 250°C, the particles may clump or grow larger due to the high temperature.

[0043] In another embodiment, among the above mixing methods, the coprecipitation method may be performed by adding the aforementioned base to the cerium source and the zirconium source to prepare a mixture solution of the cerium source and the zirconium source and the base, followed by coprecipitation. At this time, the coprecipitation may be performed at a temperature of room temperature to 100°C or lower for a predetermined period of time.

[0044] Meanwhile, step (b) is a step of calcining the mixture obtained in step (a) to obtain a composite metal oxide. Prior to the calcination, a step of pre-drying the mixture obtained in step (a) may be performed. At this time, drying may be performed using known methods and devices such as a vacuum oven, hot air, constant temperature and humidity, or microwave, and drying may be performed at 60°C to 200°C to ensure sufficient drying.

[0045] The above calcination can be performed in the range of 350°C to 800°C, typically for 2 to 8 hours. If the calcination temperature is lower than 350°C, the formation of the composite metal oxide may not be complete due to insufficient calcination, and if it exceeds 800°C, the problem of particles clumping or growing larger may occur due to the high temperature.

[0046] Thereafter, an active metal such as platinum (Pt) can be supported on the surface of the composite metal oxide obtained through the above method to produce a catalyst for dehydrogenation of glycerol. The support method can be a method that can be commonly used, and examples thereof include an adsorption method, an evaporation drying method, a spray method, and an initial wet impregnation method.

[0047] For example, the catalyst manufacturing method may include (i) a step of mixing the active metal precursor and the support solution while dropwise adding the active metal precursor solution to the dispersion solution in which the cerium-zirconium composite metal oxide support is dispersed, (ii) an aging step of stirring the mixed solution for a predetermined time after step (i), (iii) a separation step of separating the cerium-zirconium composite metal oxide support on which the active metal precursor is supported from the mixed solution after step (ii), and (iv) a step of calcining the cerium-zirconium composite metal oxide support on which the active metal precursor is supported after the separation step.

[0048] The active metal precursor in the above step (i) may be at least one selected from nitrates, sulfates, phosphoric acids, halogen salts, alkoxide salts, oxynitrates, hydrates, acetate salts, alkyl salts, hydrates thereof, etc., containing at least one element of Group 10 of the periodic table. Preferably, a halogen salt hydrate may be used. In addition, the solvent or dispersion medium in the solution in which the active metal precursor and the cerium-zirconium composite metal oxide support are dispersed may be the same or different, and any solvent or dispersion medium capable of dissolving the active metal precursor may be used without limitation, but water may be preferably used.

[0049] In the above step (ii), after the active metal precursor solution is added to the support dispersion solution, stirring is performed for a predetermined time so that the active metal precursor can be evenly supported on the support. The above step (ii) can be performed at room temperature or a temperature below the boiling point of the solvent, and the predetermined time can vary depending on conditions such as temperature, amount supported, size and quantity of the support, but can be, for example, 4 to 8 hours.

[0050] The above step (iii) is a step of separating the support on which the active metal precursor is supported from the solution. The separation method may use conventional means, and examples thereof include filtration using a filter or the like.

[0051] The above step (iv) is a step of calcining the support loaded with the active metal precursor. Prior to the calcination, a step of pre-drying the cerium-zirconium composite metal oxide support loaded with the active metal precursor obtained in step (iii) may be performed. At this time, the drying may be performed using known methods and devices such as a vacuum oven, hot air, constant temperature and humidity, and microwave, and the drying may be performed at about 60°C to 200°C so that sufficient drying is achieved. The calcination may be performed in the range of 400°C to 800°C, typically for 1 to 5 hours.

[0052] A step of reducing the calcined material after calcination may be included. The reduction step may be performed in a reducing atmosphere at a temperature range of 200°C to 300°C.

[0053] The present invention also provides a method for dehydrogenating glycerol. Specifically, the dehydrogenation reaction of glycerol is carried out by contacting a solution containing glycerol and an alkali metal or alkaline earth metal hydroxide salt with a catalyst containing a composite metal oxide of cerium and zirconium and at least one element from Group 10 of the periodic table.

[0054] The hydroxide salt of the alkali metal or alkaline earth metal may be, for example, one or more selected from KOH, NaOH, LiOH, Ca(OH)2, Mg(OH)2, etc. The temperature of the reaction is preferably in the range of 150°C to 300°C, and the hydroxide salt of the alkali metal or alkaline earth metal may be used in an amount of about 1.0 times or more, and preferably 1.0 to 3.0 times, the molar number of glycerol used. In addition, the air in the reactor before the reaction may be replaced with an inert gas.

[0055] Hereinafter, the catalytic activity of the glycerol dehydrogenation catalyst according to the present invention will be examined through examples. It should be noted that the following examples are provided to illustrate one or more preferred embodiments of the present invention, but the present invention is not limited to these embodiments. Numerous modifications to the examples below may be made within the scope of the present invention.

[0056] Catalyst Manufacturing

[0057] Manufacturing Example 1: Manufacturing of 2 wt% Pt / 5Ce-ZrO2 catalyst

[0058] 1-1: Manufacturing of the support

[0059] A mixture solution was prepared by dissolving 18.5 g of ZrOCl2·8H2O, 1.3 g of Ce(NO3)3·6H2O, and 36 g of urea in 140 ml of distilled water. The prepared mixture solution was transferred to a 250 ml Teflon-lined autoclave, heated to 200°C, and maintained at that temperature for 20 hours to carry out a hydrothermal synthesis reaction. The produced solid was then collected by filtration, washed several times with deionized water, and dried in a drying oven at 100°C for 12 hours to obtain a dried product. The dried product was placed in a kiln through which 150 cc / min of air flowed, and the temperature of the kiln was heated to 400°C at a rate of 5°C / min, and the dried product was calcined at the same temperature for 4 hours to obtain a 5Ce-ZrO2 composite metal oxide. Here, the number '5' in 5Ce-ZrO2 means that the Ce content is 5 mol% compared to the total molar content of Ce and Zr.

[0060] 1-2: Preparation of catalysts loaded with active metals

[0061] The composite metal oxide obtained in Manufacturing Example 1-1 was placed in a vessel containing distilled water, and then a solution of H2PtCl6.6H2O dissolved in distilled water was added dropwise to the vessel, and stirred at room temperature for 6 hours. After stirring, the solids were filtered to remove them, and then dried overnight in a drying oven at 100°C to obtain a dried product. The dried product was placed in a kiln in which 150 cc / min of air flowed inside, and the temperature of the kiln was heated to 500°C at a rate of 5°C / min, and the dried product was calcined at the same temperature for 2 hours. Thereafter, the calcined product was reduced at 250°C for 2 hours while flowing a H2 / Ar mixed gas containing 10% hydrogen at a flow rate of 150 cc / min before a dehydrogenation reaction in a reactor, thereby obtaining a final 2 wt% Pt / 5Ce-ZrO2 catalyst. The content of Pt in the above catalyst was 2 wt% relative to the total weight of the catalyst.

[0062] Manufacturing Example 2: Manufacturing of 2 wt% Pt / 10Ce-ZrO2 catalyst

[0063] A Pt / 10Ce-ZrO2 catalyst was obtained through the same process as Manufacturing Example 1, except that the amount of ZrOCl2·8H2O used in the manufacturing process of the support was 10 mol% of the total molar content of Ce and Zr.

[0064] Manufacturing Example 3: Manufacturing of 2 wt% Pd / 5Ce-ZrO2 catalyst

[0065] A 2 wt% Pd / 5Ce-ZrO2 catalyst was obtained through the same process as Manufacturing Example 1, except that K2PdCl4 was used instead of H2PtCl6.6H2O in the catalyst manufacturing process.

[0066] Manufacturing Example 4: Manufacturing of 2 wt% Ru / 5Ce-ZrO2 catalyst

[0067] A 2 wt% Ru / 5Ce-ZrO2 catalyst was obtained through the same process as Manufacturing Example 1, except that RuCl3·3H2O was used instead of H2PtCl6.6H2O in the catalyst manufacturing process.

[0068] Manufacturing Example 5: Manufacturing of 2 wt% Ir / 5Ce-ZrO2 catalyst

[0069] A 2 wt% Ir / 5Ce-ZrO2 catalyst was obtained through the same process as Manufacturing Example 1, except that IrCl3·xH2O was used instead of H2PtCl6.6H2O in the catalyst manufacturing process.

[0070] Manufacturing Example 6: Manufacturing of 2 wt% Pt / ZrO2 catalyst

[0071] A 2 wt% Pt / ZrO2 catalyst was obtained through the same process as Manufacturing Example 1, except that commercial zirconia (Sigma-Aldrich) was used as a support without the support manufacturing process.

[0072]

[0073] Catalyst Analysis

[0074] The catalysts of Manufacturing Examples 1, 2, and 6 were analyzed using TEM, EDS, and a particle size analyzer, and the results are shown in Fig. 2. Fig. 2 (a) shows the results of analyzing the catalyst of Manufacturing Example 1, (b) shows the results of analyzing the catalyst of Manufacturing Example 2, and (c) shows the results of analyzing the catalyst of Manufacturing Example 6.

[0075] Referring to the above Figure 2, in the case of catalysts of Preparation Examples 1 and 2 using a composite metal oxide of zirconium and cerium as a support according to the present invention, platinum (Pt) was very uniformly distributed on the support, whereas in the case of catalyst of Preparation Example 6 using zirconia (ZrO2) not containing cerium as a support, platinum (Pt) existed relatively in agglomeration, and it was confirmed that the diameter of the platinum (Pt) particles was larger than that of the catalysts of Preparation Examples 1 and 2.

[0076]

[0077] <Glycerol dehydrogenation reaction activity>

[0078] Example 1

[0079] 23.02 g (250 mmol) of glycerol, 24.04 g (375 mmol) of KOH, 23 ml of distilled water, and 0.3 g of the catalyst of Preparation Example 1 were charged into a reactor, and nitrogen gas was purged into the reactor to completely replace the air inside the reactor. The reactor was then heated to 200°C and maintained for 2 hours. The reactor was then cooled to room temperature, and the reaction results were measured and shown in Table 1.

[0080] Example 2

[0081] The results were measured through the same process as Example 1 except that the catalyst was replaced with the catalyst of Preparation Example 2, and are shown in Table 1.

[0082] Example 3

[0083] The results were measured through the same process as Example 1 except that the catalyst was replaced with the catalyst of Preparation Example 3, and are shown in Table 1.

[0084] Comparative Example 1

[0085] The results were measured through the same process as Example 1 except that the catalyst and KOH were not used, and the results are shown in Table 1.

[0086] Comparative Example 2

[0087] The results were measured through the same process as Example 1 except that no catalyst was used, and the results are shown in Table 1.

[0088] Comparative Example 3

[0089] The results were measured through the same process as Example 1 except that the catalyst was replaced with the catalyst of Manufacturing Example 4, and the results are shown in Table 1.

[0090] Comparative Example 4

[0091] The results were measured through the same process as Example 1 except that the catalyst was replaced with the catalyst of Preparation Example 5, and the results are shown in Table 1.

[0092] Comparative Example 5

[0093] The results were measured through the same process as Example 1 except that the catalyst was replaced with the catalyst of Preparation Example 6, and the results are shown in Table 1.

[0094] In Table 1 below, SBET represents the specific surface area of ​​the catalyst, GLY represents glycerol, LA represents lactic acid, CONV. represents conversion, Yield represents yield, FA represents formic acid, 1,2 PDO represents 1,2-propanediol, EG represents ethylene glycol, MA represents methanol, and GA represents glycolate.

[0095] [Table 1]

[0096]

[0097] <Catalyst stability>

[0098] Example 4

[0099] The catalyst in Example 1 was filtered again, and the process of performing the dehydrogenation reaction of glycerol as in Example 1 using it as a catalyst was repeated, and the result is shown in (a) of Figure 3.

[0100] Comparative Example 6

[0101] In the above comparative example 1, the catalyst was filtered again, and the process of performing the dehydrogenation reaction of glycerol as in Example 1 using this catalyst was repeated, and the result is shown in (b) of Fig. 3.

[0102]

[0103] As can be seen in the above Figure 3, in the case of Example 4, even if the catalyst was reused more than 5 times, the reaction activity did not decrease, but rather showed a tendency to increase slightly, whereas in the case of Comparative Example 6, the reaction activity showed a tendency to decrease as the number of times the catalyst was reused increased, confirming that the catalyst of the present invention was stable under basic conditions.

[0104] While the present invention has been described with reference to the attached drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent embodiments are possible. Accordingly, the technical protection scope of the present invention should be defined by the claims below.

[0105] The present invention is a dehydrogenation catalyst for glycerol, which comprises platinum (Pt) or the like as a catalyst active ingredient and uses a composite metal oxide containing cerium (Ce) and zirconium (Zr) as a catalyst support, thereby stably performing a dehydrogenation reaction of glycerol under basic conditions, and can be used in industrial fields that produce not only hydrogen but also high value-added lactic acid (LA) from glycerol.

Claims

1. As a catalyst for producing lactic acid by dehydrogenating glycerol in the presence of a base, A catalyst for producing lactic acid from glycerol, characterized in that an active metal containing at least one element of Group 10 of the periodic table is supported on a composite metal oxide containing zirconium (Zr) and cerium (Ce) as a catalyst support.

2. In paragraph 1, A catalyst for producing lactic acid from glycerol, characterized in that cerium in the above composite metal oxide is 0.1 mol% to 20 mol% relative to the total molar content of cerium (Ce) and zirconium (Zr).

3. In paragraph 1, A catalyst for producing lactic acid from glycerol, characterized in that the active metal is 0.1 wt% to 20 wt% based on the total weight of the catalyst. 4.(i) A step of mixing the active metal precursor and support solution by adding the active metal precursor solution dropwise to the dispersion solution in which the cerium-zirconium composite metal oxide support is dispersed; (ii) an aging step of stirring the mixed solution for a predetermined period of time after step (i); (iii) a separation step of separating a cerium-zirconium composite metal oxide support loaded with an active metal precursor from the mixed solution after step (ii); and (ⅳ) A method for producing a catalyst for producing lactic acid from glycerol, characterized in that it comprises a step of calcining a cerium-zirconium composite metal oxide support on which an active metal precursor is supported after the above separation step.

5. In paragraph 4, A method for producing a catalyst for producing lactic acid from glycerol, characterized in that it further comprises a step of drying a cerium-zirconium composite metal oxide support on which an active metal precursor is supported before the above step (iv).

6. In paragraph 4, A method for producing a catalyst for producing lactic acid from glycerol, characterized in that the calcination in the above step (iv) is performed at 400°C to 800°C.

7. In paragraph 4, A method for producing a catalyst for producing lactic acid from glycerol, characterized in that it further includes a step of reducing the calcined product at 200°C to 300°C after the above step (ⅳ).

8. In paragraph 4, A method for producing a catalyst for producing lactic acid from glycerol, characterized in that in the above cerium-zirconium composite metal oxide, cerium (Ce) is 0.1 mol% to 20 mol% based on the total molar content of cerium (Ce) and zirconium (Zr).

9. In paragraph 4, The above cerium-zirconium composite metal oxide support (a) a step of mixing a cerium source and a zirconium source; and (b) A method for producing a catalyst for producing lactic acid from glycerol, characterized in that it is produced including a step of calcining the mixture.

10. A method for producing lactic acid from glycerol, characterized in that a solution containing glycerol and an alkali metal or alkaline earth metal hydroxide is brought into contact with a catalyst having at least one element of Group 10 of the periodic table supported on a composite metal oxide support of cerium and zirconium.

11. In paragraph 10, A method for producing lactic acid from glycerol, characterized in that the hydroxide salt of the alkali metal or alkaline earth metal is used in an amount of 1.0 times or more relative to the molar content of glycerol.

12. In paragraph 10, A method for producing lactic acid from glycerol, characterized in that the content of cerium (Ce) in the above composite metal oxide support is 0.1 mol% to 20 mol% relative to the total molar content of cerium (Ce) and zirconium (Zr).

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