Catalyst for dehydrogenation reaction of glycerol and manufacturing method thereof

Abstract

The present invention relates to a catalyst for a dehydrogenation reaction of glycerol and a manufacturing method thereof and, more specifically, to a catalyst for a dehydrogenation reaction of glycerol, the catalyst being capable of effectively dehydrogenating glycerol under basic conditions to produce lactic acid with high efficiency, and a manufacturing method thereof.

Description

Catalyst for dehydrogenation of glycerol and method for producing the same

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

[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 inherent characteristics. For example, the recent increase in low-grade glycerol byproducts, driven by increased biodiesel production and usage, is being evaluated as having a limited impact on biodiesel competitiveness, along with a decline in its value due to oversupply. Therefore, converting these low-value-added glycerol byproducts into hydrogen, a high-value-added clean fuel, is a key area of ​​research and development in the field of biomass-based hydrogen production.

[0004] Glycerol is a promising hydrogen source because its dehydrogenation reaction produces not only hydrogen but also high-value lactic acid (LA). Therefore, dehydrogenation methods for producing hydrogen and lactate by dehydrogenating glycerol have been developed in recent decades.

[0005] At this time, since the glycerol dehydrogenation reaction is performed in a basic atmosphere due to the presence of metal hydroxide, a catalyst having high dehydrogenation catalytic reaction activity even in an alkaline atmosphere is required.

[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 has low stability under basic conditions and requires improvement in catalytic activity.

[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 for dehydrogenation of glycerol and a method for producing the same, which can effectively dehydrogenate glycerol under basic conditions.

[0013] In order to solve the above problem, the present invention provides a catalyst for dehydrogenation of glycerol, characterized in that at least one element of Group 10 of the periodic table is supported as a catalytically active metal on zirconium oxide having a lattice strain of 0.003 to 0.015 calculated by applying the Williamson-Hall method.

[0014] The above zirconium oxide may have an average crystallite size of 5 nm to 30 nm, and the content of the catalytically active metal may be 0.1 wt% to 20 wt% based on the total weight of the catalyst.

[0015] In the catalyst of the present invention, the active metal may preferably be at least one selected from the group consisting of platinum, palladium, and nickel, and more preferably may be platinum or palladium.

[0016] In addition, the present invention provides a method for producing a catalyst for dehydrogenation of glycerol, comprising: (i) a step of mixing a solution of a precursor of a catalytically active metal of at least one element of Group 10 of the periodic table by dropwise adding the precursor solution to a catalyst support solution in which a zirconium-containing oxide 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 the zirconium-containing oxide catalyst support on which the catalytically active metal precursor is supported from the mixed solution after step (ii); and (iv) a step of calcining the zirconium-containing oxide catalyst support on which the catalytically active metal precursor is supported after step (iii), thereby producing a glycerol dehydrogenation catalyst; wherein the zirconium-containing oxide of step (i) has a lattice strain of 0.003 to 0.015 calculated by applying the Williamson-Hall method, and the catalytically active metal precursor includes at least one element of Group 10 of the periodic table.

[0017] The zirconium-containing oxide of the above step (i) may be manufactured by including: (a) a step of mixing a zirconium precursor, a basic compound, and water in predetermined amounts to obtain a mixture; (b) a step of stirring the mixture at a predetermined temperature for a predetermined time; and (c) a step of calcining the mixture after the step (b). The zirconium precursor of the above step (a) may be zirconium oxychloride, and the basic compound may be urea. The heating in the step (a) may be in the range of 100 to 200°C, and the calcination in the step (c) may be in the range of 300 to 800°C.

[0018] In the catalyst manufacturing method of the present invention, the active metal in step (i) may be at least one selected from platinum, palladium, and nickel.

[0019] In addition, the present invention provides a method for dehydrogenating glycerol, characterized in that a mixture of glycerol and a hydroxide salt of an alkali metal or alkaline earth metal is subjected to a dehydrogenation reaction in the presence of a catalyst in which at least one element of Group 10 of the periodic table is supported as a catalytically active metal on an oxide having a lattice strain of 0.003 to 0.015 as calculated by applying the Williamson-Hall method, and including zirconium as a catalyst support.

[0020] In the method for dehydrogenating glycerol of the present invention, the hydroxide salt of the alkali metal or alkaline earth metal may be used in an amount of about 1.0 to 3.0 times or more relative to the molar number of glycerol, and the catalytically active metal may be at least one selected from the group consisting of platinum, palladium, and nickel.

[0021] According to the present invention, by including zirconium as a catalyst support and supporting at least one element of Group 10 of the periodic table as a catalytically active metal on an oxide having a specific range of lattice strain, there is an effect of high dehydrogenation reaction efficiency and stably dehydrogenating glycerol even under strongly alkaline conditions.

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

[0023] Figure 2 is an XRD measurement graph of a catalyst support (A) and a catalyst (B) manufactured in an example and comparative example of the present invention.

[0024] Figure 3 is a graph showing the results of measuring lattice strain and lactic acid yield of catalysts manufactured in examples and comparative examples of the present invention.

[0025] Figure 4 is a graph measuring the lattice strain and average crystal size of catalyst supports manufactured in examples and comparative examples of the present invention.

[0026] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined solely by the scope of the claims.

[0027] In describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description is omitted.

[0028] In the specification, when "includes," "has," "consists of," and "consists of" are used, other parts may be added unless "only" is used. When a component is expressed in the singular, the plural case is included unless otherwise explicitly stated.

[0029] In the present invention, the term "crystallite" refers to an individual crystal formed when multiple microscopic crystals come together to form a single entity, and is also called a grain. When the particle is a single crystal, the size of the crystallite may be the same as that of the particle, but when the particle is a polycrystal, the size of the crystallite is smaller than the particle size.

[0030] The present invention relates to a catalyst for dehydrogenation reaction of glycerol and a method for producing the same, and more particularly, to a catalyst for dehydrogenation reaction and a method for producing the same in a process of adding water and a metal hydroxide to glycerol and reacting them to produce an organic acid metal salt and hydrogen in a dehydrogenated form of the glycerol.

[0031] Hereinafter, a catalyst for the dehydrogenation of glycerol according to the present invention and a method for producing the same will be described in detail.

[0032] 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 the process of converting glyceraldehyde to glyceraldehyde through glyceroxide ion, an intermediate of glycerol, is reported to require high temperatures (over 550 K) in the hydrothermal process. 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 solve this problem, the reaction can be performed at low temperatures under alkaline conditions. However, alkaline conditions lead to reduced catalyst stability.

[0033] The catalyst for dehydrogenation of glycerol according to the present invention has the advantage of being stable under basic conditions while also having high dehydrogenation efficiency of glycerol.

[0034] The catalyst of the present invention may include at least one element from Group 10 of the periodic table as an active metal, and may be characterized in that the catalyst support is zirconium oxide having a specific range of lattice strain.

[0035] In the present invention, the active metal of the catalyst can be applied without limitation as long as it is an element of Group 10 of the periodic table, and specifically, it can be platinum, palladium, nickel, etc., and more specifically, it can be platinum, palladium, etc.

[0036] The above catalytically active metal may be 0.1 wt% to 20 wt%, preferably 0.1 wt% to 10 wt%, based on the total weight of the catalyst. If the content of the active metal is less than 0.1 wt%, the conversion rate of glycerol may decrease, and if it exceeds 20 wt%, even if the content of the active metal increases, the CC bond is broken, resulting in a decrease in selectivity. Therefore, the effect of increasing activity relative to the content of the catalytically active metal is not significant, and thus it may not be economical.

[0037] The above catalytically active metal may be supported on a zirconium-containing oxide as a catalyst support, and the lattice strain of the zirconium-containing oxide may be 0.003 to 0.015, preferably 0.006 to 0.010.

[0038] When the lattice strain of the zirconium-containing oxide is less than 0.003, low bonding between the metal and the carrier may occur due to stabilization of the crystal structure of zirconium, which may cause sintering of Pt particles. In addition, when a strain is applied to the zirconium crystal by adding metal to the lattice of ZrO2 and exceeds 0.015, the structure of zirconium may change from a monoclinic to a tetragonal structure, which may cause problems with low activity and safety.

[0039] Accordingly, in the catalyst for the dehydrogenation reaction of glycerol, when the lattice strain of the zirconium-containing oxide satisfies the above range, high stability and activity can be promoted due to increased bonding between the metal and the carrier.

[0040] At this time, the lattice strain can be calculated by applying the Williamson-Hall method defined by Equation 1 below to XRD peaks measured through X-ray diffusion (XRD) analysis.

[0041] βcosθ = ε(4sinθ) +Kλ / D.....(1)

[0042] In Equation 1, β represents the full width at half maximum (FWHM) (rad) of the corresponding peak obtained through XRD analysis, θ represents the diffraction angle (rad), ε represents the lattice strain (dimensionless number), λ represents the X-ray wavelength (Å), D represents the crystallite size (Å), and K represents the shape factor (0.9).

[0043] The above XRD analysis can be performed on dried powder of zirconium-containing oxide particles using Cu rays as a light source, at a diffraction angle (2θ) range of 10° to 70°, and a scan rate of 0.02° / step. After measuring the half-width of all peaks appearing in the above diffraction angle range, the obtained measurement values ​​are substituted into Equation 1 and the slope is obtained through linear regression analysis to calculate the lattice strain (Williamson-Hall method). For example, the lattice strain can be defined as the slope of a straight line obtained when Equation 1 is plotted with sinθ as the horizontal axis and βcosθ as the vertical axis.

[0044] In addition, the zirconium-containing oxide may have an average crystallite size calculated from the broadening of peaks appearing according to XRD measurement, of 5 nm to 30 nm, preferably 13 nm to 25 nm.

[0045] At this time, when the average crystal grain size of the zirconium-containing oxide is in the range of 5 nm to 30 nm, the carrier is stable even in a basic atmosphere, and the Pt metal can be effectively dispersed. The catalyst support according to the present invention composed of the zirconium-containing oxide has a specific surface area (BET) of 30 m 2 / g or more, and the average pore size may be 5 nm to 30 nm or less. When the average pore size of the catalyst support is within the above range, the catalyst manufacturing process becomes simpler, and the distribution efficiency of the active metal increases, resulting in an effect of increasing the lactic acid yield.

[0046] The above-described catalyst support properties, such as lattice strain, average grain size, specific surface area, and pore size, can be controlled by adjusting the conditions when synthesizing a metal oxide by treating a precursor of the metal forming the catalyst support; for example, temperature, time, and pressure during hydrothermal synthesis for forming grains, and simultaneous (one-pot) or separate production of the active metal and the support; or the sintering conditions when obtaining the metal oxide; for example, sintering temperature, heating rate during heating, and heating time.

[0047] Such a catalyst support has excellent durability even under strong alkaline conditions, and can stably perform a dehydrogenation reaction, thereby increasing the conversion rate of glycerol and the selectivity of lactic acid.

[0048] The method for preparing a catalyst for dehydrogenation of glycerol according to the present invention may include (i) a step of mixing a solution of a catalytically active metal precursor of at least one element of Group 10 of the periodic table by dropwise adding the solution to a catalyst support solution in which zirconium oxide is dispersed; (ii) an aging step of stirring the mixed solution for a predetermined period of time after step (i); and (iii) a step of preparing a glycerol dehydrogenation catalyst by calcining a zirconium oxide catalyst support on which the catalytically active metal precursor is supported.

[0049] The catalyst support in the above step (i) can be manufactured by including the steps of (a) mixing a zirconium precursor, a basic compound, and water in predetermined amounts to obtain a mixture; (b) stirring the mixture at a predetermined temperature for a predetermined time; and (c) calcining the mixture after the step (b).

[0050] The type of zirconium precursor in the above step (a) is not limited, but may preferably be one selected from among zirconium-containing hydroxides or chlorides. The basic compound mixed in the above step may also include an alkali metal hydroxide or an alkaline earth metal hydroxide and ammonia. In addition, a secondary, tertiary, or quaternary amine may be used, and preferably urea.

[0051] The step (b) above is a step of heating and reacting the mixture from step (a). In the step (a), the heating may be performed at a temperature ranging from 100°C to 200°C, preferably from 160°C to 200°C, and stirring may be performed for 1 hour to 30 hours, preferably from 10 hours to 20 hours. When the temperature range is from 100°C to 200°C, the formation of a monoclinic phase rather than a tetragonal structure of zirconium oxide may be promoted.

[0052] In the subsequent step (c), the zirconium oxide shape can be obtained by firing. The firing temperature can be 300°C to 800°C. If the firing temperature is lower than 300°C, the oxide formation may not be complete due to insufficient firing, and if it exceeds 800°C, the problem of particles clumping or growing larger due to the high temperature may occur.

[0053] The catalytically active metal precursor in the above step (i) may be at least one selected from nitrates, sulfates, phosphoric acids, halogen salts, alkoxide salts, oxynitrates, hydroxides, acetate salts, alkyl salts, hydrates thereof, etc. containing at least one of the elements of Group 10 of the aforementioned periodic table, and preferably, a halogen salt hydrate may be used.

[0054] In addition, the catalyst support solution in which the catalytically active metal precursor solution and the zirconium oxide are dispersed can be uniformly mixed by adding the catalytically active metal precursor and the zirconium oxide to a solvent compound, and the solvent compound can be used without limitation as long as it can dissolve the catalytically active metal precursor, but water can be preferably used.

[0055] As the above active metal, the group 10 element may preferably be platinum, palladium, nickel, etc., and more preferably may be platinum, palladium, etc.

[0056] (ii) Step 1 is to mix the catalyst active metal precursor solution by adding dropwise to the catalyst support solution in which zirconium oxide is dispersed, and then to stir for a predetermined period of time so that the catalyst active metal precursor can be evenly supported on the catalyst support.

[0057] 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 of support, size and amount of support, etc., but can be, for example, 4 to 8 hours.

[0058] Meanwhile, step (iii) is a step of separating the catalyst support on which the catalytically active metal precursor is supported from the solution. The separation can be accomplished using conventional means, and examples thereof include filtration using a filter or the like.

[0059] Step (iv) is a step of calcining the catalyst support loaded with the catalytically active metal precursor, which can be performed at a temperature ranging from 400°C to 800°C, typically for 1 to 5 hours. Prior to step (iv), a step of pre-drying the catalyst support loaded with the catalytically active metal precursor obtained in step (iii) may be performed. At this time, the drying can be performed using known methods and devices such as a vacuum oven, hot air, constant temperature and humidity, and microwave, and the drying can be performed so that sufficient drying is achieved.

[0060] In addition, after the step (iv), a step of reducing the calcined material may be included. The reduction step may be performed in a reducing atmosphere at a temperature range of 120°C to 350°C.

[0061] Meanwhile, the present invention provides a method for dehydrogenating glycerol. Specifically, the method for dehydrogenating glycerol according to the present invention performs a dehydrogenation reaction on a mixture of glycerol and an alkali metal or alkaline earth metal hydroxide in the presence of a catalyst in which at least one element from Group 10 of the periodic table is supported as a catalytically active metal on an oxide having a lattice strain of 0.003 to 0.015 as calculated by applying the Williamson-Hall method. At this time, the alkali metal or alkaline earth metal hydroxide may be, for example, one or more selected from KOH, NaOH, LiOH, Ca(OH)2, Mg(OH)2, etc.

[0062] The active metal of the above catalyst can be applied without limitation as long as it is an element of Group 10 of the periodic table, and specifically, it can be at least one selected from platinum, palladium, and nickel, and more specifically, it can be platinum, palladium, etc.

[0063] In addition, the dehydrogenation reaction can be performed at 150°C to 250°C, and the hydroxide salt of the alkali metal or alkaline earth metal can be used in an amount of about 1.0 to 3.0 times the mole number of glycerol used. In addition, the air in the reactor before the reaction can be replaced with an inert gas.

[0064] Hereinafter, the catalytic activity of the catalyst for glycerol dehydrogenation 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.

[0065] <Example of zirconium oxide formation through hydrothermal synthesis>

[0066] <Example 1>

[0067] A mixture solution was prepared by dissolving 19.5 g of ZrOCl2ㆍ8H2O 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 resulting solid was collected by filtration, washed several times with deionized water, and then 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 ZrO2.

[0068] The obtained ZrO2 was placed in a container containing distilled water, and then a solution of H2PtCl6.6H2O dissolved in distilled water was added dropwise to the container, and stirred at room temperature for 6 hours. After stirring, the solids were filtered out, and then dried overnight in a drying oven at 100°C to obtain a dried product. The dried product was placed in a kiln with 150 cc / min of air flowing inside, and the temperature of the kiln was heated to 500°C at a rate of 5°C / min, and the dried product was fired at the same temperature for 2 hours.

[0069] Afterwards, the above-mentioned calcined material was subjected to a reduction reaction at 250°C for 2 hours before undergoing a dehydrogenation reaction in a reactor while flowing a H2 / Ar mixed gas containing 10 vol% of hydrogen at a flow rate of 150 cc / min, thereby producing a final 2 wt% Pt / ZrO2 catalyst. The content of Pt in the catalyst was 2 wt% based on the total weight of the catalyst.

[0070] <Example 2>

[0071] A catalyst was manufactured using the same method as in Example 1 (a) except that the calcination temperature was changed to 600°C in the catalyst support manufacturing process.

[0072] <Comparative Example 1>

[0073] A 2 wt% Pt / ZrO2 catalyst was obtained through the same process as Example 1, except that commercial zirconia [Sigma Aldrich] was used as a support without a support manufacturing process.

[0074] <XRD 분석>

[0075] In order to analyze the crystal information of the catalyst support and catalyst manufactured in the examples and comparative examples, XRD (Rigaku, D / Maz-2200V) analysis was used, and the results are shown in Fig. 2.

[0076] (A) of the above Fig. 2 is an XRD pattern graph for each catalyst support, and (B) is an XRD pattern graph of a catalyst manufactured using the support. In (A) and (B) of Fig. 2, a) is the catalyst support and catalyst obtained in Comparative Example 1, b) is the catalyst support and catalyst obtained in Example 1, and c) is the catalyst support and catalyst obtained in Example 2.

[0077] In addition, the above-described Figure 3 is a graph showing the results of measuring the crystal grain size using the lattice strain and Scherrer Equation for the catalyst support calculated by Equation 1 through the XRD pattern analysis.

[0078] As shown in (A) of Fig. 2, it can be confirmed that the synthesized zirconia carrier has a smaller crystal structure and a larger lattice strain value compared to commercial zirconia purchased from Sigma-Aldrich.

[0079] As shown in (B) of Fig. 2, when the synthesized zirconia carrier was used, no peak corresponding to Pt was observed, but in the case of commercial zirconia, a Pt peak was observed, confirming the high dispersion of Pt when the synthesized carrier was used.

[0080] In particular, as shown in FIGS. 3 and 4, in the case of the catalyst supports obtained in Examples 1 and 2, it was confirmed that the lattice strain increased and the average crystal grain size became significantly smaller compared to Comparative Example 1.

[0081] <o2-tpd>

[0082] In order to analyze the oxygen vacancy of the catalyst support and catalyst manufactured in the examples and comparative examples, O2-TPD (Micromeritics AutoChem II 2920 V4.06) was measured, and the results are shown in Table 1. The O2-TPD measured surface oxygen species and defects on the catalyst surface.

[0083] [Table 1]

[0084]

[0085] The above O2-TPD was performed to evaluate the surface oxygen species and defects of the catalyst, and the peaks observed below 300 °C and above 700 °C were respectively surface physically absorbed oxygen (O P ) and bulk lattice oxygen (O BL ) is due to the desorption of oxygen, and the peak between 300 ℃ and 700 ℃ is due to the chemically adsorbed oxygen (O C ) and surface lattice oxygen (O SL ) due to the desorption of O. The commercial ZrO2 of comparative example 1 has negligible O C and O SL In contrast to the almost defect-free supports shown in Examples 1 and 2, all the synthesized supports showed O C and O SL The values ​​indicate that the synthetic sample possesses a high number of surface oxygen vacancies or defects.

[0086] <Effect on the dehydrogenation reaction activity of glycerol>

[0087] In order to measure the activity of the catalysts of Examples 1 and 2 and Comparative Example 1 for glycerol dehydrogenation reaction, the following experiment was conducted.

[0088] 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 catalysts of Examples 1 and 2 and Comparative 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 2 and Fig. 3.

[0089] Figure 3 is a graph showing the results of the lattice strain of the catalyst support and the lactic acid yield measured in the XRD measurement of the analysis example by example. In addition, in Table 2 below, GLY means glycerol, LA means lactic acid, CONV. means conversion, Yield means yield, FA means formic acid, 1,2 PDO means 1,2-propanediol, EG means ethylene glycol, MA means methanol, and GA means glycolate.

[0090] [Table 2]

[0091]

[0092] As shown in Table 2, among the tested catalysts, Pt / ZrO2 supported on commercial ZrO2 showed the lowest conversion (83.4%) and LA yield (69.5%). However, in Examples 1 and 2, where Pt was supported on the synthesized ZrO2, it was observed that both the conversion and LA yield were improved, and the highest LA yield (74.6%) and glycerol conversion (87.2%) were achieved in Example 2.

[0093] To better understand the differences in catalytic activity among catalysts for the reaction from glycerol to LA, as shown in Fig. 3, the LA yield was plotted against the lattice strain of the support. As shown, the LA yield increased as the lattice strain increased. This indicates that the strain of the support plays a favorable role in the adsorption of glycerol on the catalyst surface, thereby improving the LA yield.

[0094] <Example of zirconium oxide formation without hydrothermal synthesis>

[0095] Examples 3 and 4 are examples of producing zirconium oxide exhibiting a large lattice strain while obtaining the oxide directly from a zirconium precursor without using hydrothermal synthesis.

[0096] <Example 3>

[0097] Dissolve 0.27 g of H2PtCl6.6H2O in 100 ml of distilled water, add 4.9 g of Zr(OH)4 dropwise to the solution, and mix evenly at room temperature for 6 hours. After drying the powder at 100°C for 12 hours, the temperature was raised to 650°C (heating rate of 5 minutes per minute) in a 5% H2 / Ar atmosphere (flow rate of 150 cc) and maintained for 2 hours to produce a 2% Pt / ZrO2 catalyst (surface area of ​​65 m 2 / g). XRD structural analysis results confirmed that it was Monoclinic ZrO2, and the lattice strain calculated from the half width was 0.010.

[0098] <Example 4>

[0099] ZrO2 powder was prepared by calcining 10 g of Zr(OH)4 at 650 ℃ for 4 hours (surface area 100 m 2 / g). The above 4.9 g ZrO2 powder was added to 100 ml of distilled water, and 27 g H2PtCl6.6H2O was added dropwise. The mixture was mixed at room temperature for 10 hours, filtered to remove solids, and dried at 100°C for 24 hours. After the powder was calcined at 500°C for 2 hours, the temperature was raised to 250°C in a 5% H2 / Ar atmosphere and maintained for 2 hours to produce a 2% Pt / ZrO2 catalyst (surface area 42 m 2 / g). XRD structural analysis results confirmed that it was monoclinic ZrO2, and the lattice strain calculated from the half width was 0.007.

[0100] <Comparative Example 2>

[0101] A 2 wt% Pt / ZrO2 catalyst was obtained through the same process as Example 4, except that commercial zirconia [Sigma Aldrich] was used as the support. The lattice strain calculated from the half width was 0.002.

[0102] Dehydrogenation of glycerol

[0103] In order to measure the activity of the catalysts of Examples 3 and 4 and Comparative Example 2 for glycerol dehydrogenation reaction, the following experiment was conducted.

[0104] 138 g (1.5 mol) of glycerol, 126 g (2.25 mol) of KOH, 140 ml of distilled water, and 2.1 g of the catalysts of the examples and comparative examples were charged into a 1 L 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 3.5 hours. The reactor was then cooled to room temperature, and the reaction results were measured and shown in Table 3.

[0105] [Table 3]

[0106]

[0107] Table 3 shows an overall high glycerol conversion and LA yield due to the long reaction time compared to Table 2 above. However, when comparing the relative values ​​of Comparative Example 2 and Examples 3 and 4, Pt / ZrO2 supported on commercial ZrO2 with a lattice strain of only 0.002 showed a lower LA yield compared to Examples 3 and 4, which have lattice strain values ​​within the scope of the present invention, showing the same trend as Table 2 above. This confirms that the lattice strain value of zirconium oxide is an important factor in catalytic activity.

[0108] In the subsequent reuse experiment, the catalyst of Comparative Example 2 showed only about 85% of the activity (glycerol conversion rate) compared to the initial use due to the agglomeration of the catalyst after 5 reuses, but Examples 3 and 4 showed an activity of more than 95% even after 5 reuses, indicating that the catalyst according to the present invention also showed high stability.

[0109] 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.

Claims

1. In a catalyst for dehydrogenating glycerol in the presence of a base, A catalyst for the dehydrogenation reaction of glycerol, characterized in that the catalyst comprises zirconium as a catalyst support, and at least one of the elements of Group 10 of the periodic table is supported as a catalytically active metal on an oxide having a lattice strain of 0.003 to 0.015 calculated by applying the Williamson-Hall method.

2. In paragraph 1, The above catalyst support is a catalyst for dehydrogenation reaction of glycerol, characterized in that the average crystallite size of the oxide is 5 nm to 30 nm.

3. In paragraph 1, A catalyst for dehydrogenation reaction of glycerol, characterized in that the content of the above catalytically active metal is 0.1 wt% to 20 wt% with respect to the total weight of the catalyst.

4. In paragraph 1, A catalyst for dehydrogenation reaction of glycerol, characterized in that the catalytically active metal comprises at least one selected from the group consisting of platinum, palladium, and nickel. 5.(i) A step of mixing by dropwise adding a catalyst active metal precursor solution of at least one element of group 10 of the periodic table to a catalyst support solution in which a zirconium-containing oxide 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 zirconium-containing oxide catalyst support loaded with a catalytically active metal precursor from the mixed solution after step (ii); and (ⅳ) a step of preparing a dehydrogenation catalyst of glycerol by calcining a zirconium-containing oxide catalyst support on which a catalytically active metal precursor is supported after the step (ⅲ); A method for producing a catalyst for dehydrogenation of glycerol, characterized in that the zirconium-containing oxide of the above step (i) has a lattice strain of 0.003 to 0.015 calculated by applying the Williamson-Hall method, and the catalytically active metal precursor contains at least one element of group 10 of the periodic table.

6. In paragraph 5, The zirconium-containing oxide of step (i) above (a) a step of obtaining a mixture by mixing a zirconium precursor, a basic compound, and water in predetermined amounts; (b) a step of stirring the mixture at a predetermined temperature for a predetermined time; (c) A method for producing a catalyst for dehydrogenation reaction of glycerol, characterized in that it is produced including a step of calcining the mixture after step (b).

7. In paragraph 5, A method for producing a catalyst for dehydrogenation reaction of glycerol, characterized in that the active metal in the above step (i) is at least one selected from platinum, palladium, and nickel.

8. In paragraph 5, A method for producing a catalyst for dehydrogenation reaction of glycerol, characterized in that in step (a), heating is in the range of 100 ℃ to 200 ℃, and in step (c), calcination is in the range of 300 ℃ to 800 ℃.

9. A method for dehydrogenating glycerol, characterized in that a mixture of glycerol and a hydroxide salt of an alkali metal or alkaline earth metal is subjected to a dehydrogenation reaction in the presence of a catalyst in which at least one element of Group 10 of the periodic table is supported as a catalytically active metal on an oxide having a lattice strain of 0.003 to 0.015 calculated by applying the Williamson-Hall method, and containing zirconium as a catalyst support.

10. In paragraph 9, A method for dehydrogenating glycerol, characterized in that the hydroxide salt of the alkali metal or alkaline earth metal is used in an amount of 1.0 to 3.0 times or more relative to the mole number of glycerol.

11. In paragraph 9, A method for dehydrogenating glycerol, characterized in that the catalytically active metal comprises at least one selected from the group consisting of platinum, palladium, and nickel.

12. In paragraph 9, A method for dehydrogenating glycerol, characterized in that the above dehydrogenation reaction is performed at 150°C to 250°C.

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