Method for preparing 2-methyltetrahydrofuran using mixture of compounds derived from lignocellulosic biomass, catalyst used therefor, and method for preparing catalyst

Abstract

The present invention relates to a method for preparing 2-methyltetrahydrofuran using a mixture of compounds derived from lignocellulosic biomass, a catalyst used therefor, and a method for preparing the catalyst. According to the present invention, 2-methyltetrahydrofuran can be prepared in high yield from a mixed lignocellulosic biomass-derived compound by performing a hydrogenation dehydration reaction using a furfural compound and a levulinic acid compound as reactants, and the effect can be maximized through optimization of the composition and reaction conditions of the reactants. In addition, the selectivity of 2-MTHF can be further improved by using a catalyst in which nickel and copper, which are non-noble metal-based materials, are supported on an acid support in the reaction.

Description

Method for producing 2-methyltetrahydrofuran using a mixture of compounds derived from woody biomass, catalyst used therein, and method for producing the catalyst

[0001] The present invention relates to a method for producing 2-methyltetrahydrofuran using a mixture of compounds derived from woody biomass, a catalyst used therein, and a method for producing the catalyst. More specifically, the present invention relates to a method for producing 2-methyltetrahydrofuran by reacting furfural compounds and levulinic acid compounds, which are woody biomass-derived compounds, a catalyst used therein, and a method for producing the catalyst.

[0002] Lignocellulosic biomass refers to a resource derived from herbaceous plants, primarily composed of cellulose and hemicellulose. Lignocellulosic biomass can be converted into various industrial chemicals that can replace fossil fuels through chemical reactions, and is therefore attracting attention as a resource for producing carbon-reducing chemical raw materials.

[0003] An example of a material that can be synthesized from lignocellulosic biomass is 2-methyltetrahydrofuran (MTHF). 2-Methyltetrahydrofuran can be used in a variety of applications, including as a solvent for oil extraction and organic chemical reactions, as an electrolyte, and as a gasoline additive. For example, Korean Patent Laid-Open Publication No. 10-2000-0055681 describes a polymer blend electrolyte and an electrochemical cell utilizing the same, and notes that 2-methyltetrahydrofuran can be used as an organic electrolyte.

[0004] Thus, 2-methyltetrahydrofuran is a versatile substance, and its synthesis from biomass-derived compounds can be utilized as a high-value-added compound. However, because the 2-methyltetrahydrofuran synthesis reaction generates a wide variety of intermediates, establishing an appropriate reaction environment and conditions has been a limitation.

[0005] Accordingly, research has been conducted to increase selectivity during 2-methyltetrahydrofuran synthesis, and a representative method is a method using a catalyst. For example, U.S. Patent Publication No. 5,883,266 relates to a hydrogenated 5-carbon compound and a method for producing the same, and describes that a high-yield reaction can be achieved when a catalyst prepared using palladium and rhenium is used. However, the technology had the problem of poor economic feasibility because it used a catalyst mainly composed of precious metals.

[0006] Accordingly, there is a need for the development of a technology capable of producing 2-methyltetrahydrofuran in a high yield in an economical and simple manner.

[0007] One object of the present invention is to provide a method for producing 2-methyltetrahydrofuran (MTHF) in high yield from a compound derived from woody biomass.

[0008] Another object of the present invention is to provide a catalyst capable of improving the selectivity of MTHF in the production of 2-methyltetrahydrofuran.

[0009] Another object of the present invention is to provide a method for producing the catalyst.

[0010] In order to achieve the above object, the present invention provides a method for producing 2-methyltetrahydrofuran, which comprises a step of obtaining 2-methyltetrahydrofuran (MTHF) by hydrogenating and dehydrating a furfural compound and a levulinic acid compound.

[0011] In the present invention, the volume ratio of the furfural compound and the levulinic acid compound may be 1:5 to 10:1.

[0012] In the present invention, the reaction can be performed under a pressure of 10 to 50 bar.

[0013] In the present invention, the reaction can be performed at a temperature of 150 to 400°C.

[0014] In the present invention, the solvent used in the reaction may include at least one selected from the group consisting of ethanol, propanol, butanol, toluene, cyclopentyl methyl ether (CPME), gamma valerolactone (GVL), and methyl isobutyl ketone (MIBK).

[0015] In the present invention, the reaction can be carried out in the presence of an acid support and a catalyst comprising nickel and copper metals supported on the acid support.

[0016] In the present invention, the reaction can be performed in a batch reactor or a continuous reactor.

[0017] In the present invention, the method for producing 2-methyltetrahydrofuran can be performed by a two-step continuous reaction comprising the steps of converting a portion of levulinic acid in woody biomass containing furfural and levulinic acid into gamma valerolactone; and the step of reacting the furfural and residual levulinic acid to obtain 2-methyltetrahydrofuran.

[0018]

[0019] The present invention also provides a catalyst for producing 2-methyltetrahydrofuran, comprising an acid support and nickel and copper metals supported on the acid support.

[0020] In the present invention, the acid support may include at least one selected from the group consisting of aluminum oxide, zirconium oxide, zinc oxide, titanium oxide, magnesium oxide, cerium oxide, and lanthanum oxide.

[0021]

[0022] The present invention also provides a method for producing the catalyst for producing 2-methyltetrahydrofuran.

[0023] The catalyst manufacturing method of the present invention may include a step of mixing and stirring a nickel salt and a copper salt on an acid support; and a step of drying, calcining, and reducing the mixture after the stirring is completed, thereby forming a catalyst in which nickel and copper are supported on the acid support.

[0024] In the present invention, the acid support can be manufactured through the steps of: stirring a metal salt solution and adding an acid to form a sol; drying the sol to obtain a xerogel; and pulverizing and calcining the xerogel to obtain an acid support.

[0025] In the present invention, the metal salt solution may contain aluminum alkoxide and zirconium alkoxide in a weight ratio of 1:1 to 10:1.

[0026] In the catalyst manufacturing method of the present invention, the drying process can be performed at a temperature of 60 to 150°C.

[0027] In the catalyst manufacturing method of the present invention, the calcination process can be performed at a temperature of 350 to 600°C.

[0028] According to the present invention, by performing a hydrogenation dehydration reaction using a furfural compound and a levulinic acid compound as reactants, 2-methyltetrahydrofuran can be produced in high yield from a mixed wood-based biomass-derived compound, and the above effect can be maximized through optimization of the composition of the reactants and reaction conditions. In addition, the selectivity of 2-methyltetrahydrofuran can be further improved by using a catalyst in which non-precious metals such as nickel and copper are supported on an acid support for the reaction.

[0029] Figure 1 shows the reaction path of a hydrogenation dehydration reaction according to one embodiment of the present invention.

[0030] Figure 2 illustrates a catalyst synthesis process using a wet impregnation method according to one embodiment of the present invention.

[0031] Figure 3 illustrates a catalyst support synthesis process using a sol-gel method according to one embodiment of the present invention.

[0032] Figure 4 shows a nitrogen adsorption isotherm of a catalyst manufactured using a wet impregnation method according to one embodiment of the present invention.

[0033] FIG. 5 shows an XRD pattern of a catalyst manufactured using a wet impregnation method according to one embodiment of the present invention.

[0034] FIG. 6 shows a TEM image of a catalyst manufactured using a wet impregnation method according to one embodiment of the present invention.

[0035] Figure 7 shows a nitrogen adsorption isotherm of a catalyst manufactured using a sol-gel method according to one embodiment of the present invention.

[0036] Figure 8 shows an XRD pattern of a catalyst manufactured using a sol-gel method according to one embodiment of the present invention.

[0037] Figure 9 shows a TEM image of a catalyst manufactured using a sol-gel method according to one embodiment of the present invention.

[0038] Figure 10 shows the results of ammonia temperature-elevated desorption analysis of a catalyst manufactured using a sol-gel method according to one embodiment of the present invention.

[0039] Figure 11 is a graph showing the selectivity of a product according to reaction time in a 2-methyltetrahydrofuran synthesis reaction according to one embodiment of the present invention.

[0040] Hereinafter, specific implementations of the present invention will be described in more detail. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which the present invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

[0041]

[0042] The present invention relates to a method for producing 2-methyltetrahydrofuran (MTHF) from a chemical substance derived from woody biomass and a catalyst used therein.

[0043] 2-Methyltetrahydrofuran (MTHF) is used as a solvent in oil extraction and organic chemical reactions, as well as a gasoline additive. When MTHF is synthesized from biomass-derived compounds, it can be utilized as a high-value-added compound. However, because the MTHF synthesis reaction produces a wide variety of intermediates, establishing an appropriate reaction environment and conditions has been challenging.

[0044] The present invention aims to overcome these limitations of conventional technology. By combining a furfural compound and a levulinic acid compound as reactants during 2-methyltetrahydrofuran synthesis, the selectivity for MTHF can be improved. Furthermore, by utilizing a catalyst comprising non-precious metals such as nickel and copper supported on an acid support, the conversion rate to MTHF can be increased.

[0045] Specifically, in the present invention, a furfural (FUR) compound and a levulinic acid (LA) compound are combined and reacted as shown in FIG. 1, thereby undergoing various chemical reactions including hydrogenation and dehydration. In this process, tetrahydrofurfuryl alcohol (THFOL) and gamma-valerolactone (GVL), which are reaction intermediates that can be further converted into 2-methyltetrahydrofuran (MTHF), are generated, thereby improving the yield of MTHF, and the yield of MTHF can be maximized through optimization of the composition of the reactants and the reaction conditions. In addition, since the furfural and levulinic acid used in the present invention are hemicellulose-derived and cellulose-derived substances, respectively, lignocellulosic biomass can be used in its entirety in the reaction of the present invention.

[0046] Accordingly, the present invention can provide a method for producing 2-methyltetrahydrofuran by hydrogenating and dehydrating a furfural compound and a levulinic acid compound. In the present invention, the furfural compound, the levulinic acid compound, and the 2-methyltetrahydrofuran compound are interpreted to include each substance and its derivatives.

[0047] In the present invention, by using a furfural compound or a levulinic acid compound as a mixed reactant for MTHF synthesis, the selectivity of MTHF can be greatly improved compared to when each compound is used alone.

[0048] In the present invention, the furfural compound and the levulinic acid compound may be mixed in a volume ratio of 1:5 to 10:1, preferably 2:3 to 8:1, and more preferably 3:2 to 5:1. In the above range, the effect of improving MTHF selectivity by using the combined furfural compound and levulinic acid compound is maximized, so that MTHF can be obtained in a high yield.

[0049] In relation to this, in the embodiment of the present invention, the reaction was performed by adjusting the volume ratio of furfural and levulinic acid to 1:4, 2:3, 1:1, 3:2, 4:1, and 7:1 under the same conditions, respectively. As a result, it was confirmed that when the ratio of furfural and levulinic acid was 4:1, the GVL ratio was greatly reduced and the selectivity of MTHF was the best.

[0050] In the present invention, the reaction pressure may be 10 to 50 bar, preferably 20 to 45 bar, and more preferably 25 to 40 bar. By adjusting the reaction pressure in this way, the conversion rate to MTHF can be improved. In this regard, in an example of the present invention, the reaction pressure was adjusted to 10, 20, and 30 bar under the same conditions, and it was confirmed that the selectivity for MTHF was the best under the 30 bar condition.

[0051] In the present invention, the reaction temperature may be 150 to 400°C, preferably 180 to 350°C, and more preferably 220 to 300°C. By controlling the reaction temperature within the above range, the conversion rate to MTHF can be improved. In this regard, in an embodiment of the present invention, the reaction temperature was controlled to 150, 200, and 250°C under the same conditions, and it was confirmed that the selectivity for MTHF was highest at 250°C.

[0052] In the present invention, the above reaction can be carried out in a solution phase. At this time, one or more solvents such as ethanol, propanol, butanol, toluene, cyclopentyl methyl ether (CPME), gamma valerolactone (GVL), and methyl isobutyl ketone (MIBK) can be used as the reaction solvent, and propanol or toluene is preferably used.

[0053] In relation to this, in the examples of the present invention, when 2-propanol, toluene, cyclopentyl methyl ether (CPME), gamma valerolactone (GVL), or methyl isobutyl ketone (MIBK) was used as a reaction solvent, it was confirmed that the MTHF conversion rate was the best at 72.0% when toluene was used, and the conversion rate was high at 55.0% when 2-propanol was used, whereas the conversion rates were low at 39.0, 22.0, and 18.0% when CPME, MIBK, and GVL were used, respectively.

[0054] In the present invention, the reaction may be carried out in a batch reactor or a continuous reactor.

[0055] The above batch reactor is a device that mixes and reacts raw materials and then discharges them all at once, and the above continuous reactor is a reactor that continuously adds and stirs raw materials and continuously discharges them after the reaction is complete. The reaction of the present invention shows a higher conversion rate to MTHF when carried out in a batch reactor, but even when using a continuous reactor, the effect of improving MTHF selectivity due to the combined use of furfural and levulinic acid can be confirmed.

[0056] When the reaction is carried out in the continuous reactor, the weight hourly space velocity (WHSV) of the feedstock can be controlled to 0.05 to 1 mL / min, preferably 0.1 to 0.5 mL / min.

[0057] In one embodiment of the present invention, the reaction may be carried out as a two-step continuous reaction. The two-step continuous reaction may be performed through a step of converting a portion of the levulinic acid in the woody biomass containing furfural and levulinic acid into gamma valerolactone; and a step of reacting the furfural and the residual levulinic acid to synthesize MTHF.

[0058] Since the amount of cellulose-derived levulinic acid derived from initial lignocellulosic biomass is greater than the amount of furfural derived from hemicellulose, in order to optimize the ratio of furfural and levulinic acid, a portion of the levulinic acid is first converted to gamma valerolactone, which can be used as a reaction solvent, and then the reaction is performed. This allows for efficient production of MTHF using lignocellulosic biomass with a high levulinic acid ratio.

[0059] When MTHF is produced using a furfural compound and a levulinic acid compound as reactants according to the present invention, the yield of MTHF can be increased compared to when they are used alone, and the selectivity of MTHF can be greatly improved by controlling the ratio and reaction conditions thereof.

[0060] In addition, the MTHF selectivity can be further improved by performing the above reaction in the presence of a bimetallic catalyst.

[0061]

[0062] Accordingly, the present invention can also provide a catalyst used in hydrogenation and dehydration reactions in the production of 2-methyltetrahydrofuran (MTHF).

[0063] The catalyst for MTHF production of the present invention comprises an acid support and nickel and copper metals supported on the acid support. When the catalyst is applied to an MTHF synthesis reaction, the selectivity toward MTHF can be improved. The catalyst of the present invention can be produced through a simple impregnation method, and since it utilizes an acid support and a non-precious metal material, it is economical, has excellent stability, and is easy to handle as a catalyst production raw material.

[0064] In the present invention, the acid support of the catalyst may include one or more metal oxides, such as aluminum oxide, zirconium oxide, zinc oxide, titanium oxide, magnesium oxide, cerium oxide, lanthanum oxide, etc.

[0065] In the present invention, the acid support preferably comprises aluminum oxide. In this regard, in an embodiment of the present invention, when aluminum oxide and zirconium oxide were used as the acid support for the catalyst, it was confirmed that the catalyst manufactured using the aluminum oxide support had a significantly superior MTHF conversion rate enhancement effect.

[0066] In one embodiment of the present invention, the acid support may include aluminum oxide and zirconium oxide. In this case, the conversion rate to MTHF can be further increased by adjusting the ratio of aluminum oxide and zirconium oxide.

[0067] In the present invention, by using nickel and copper as components supported on an acid support, the selectivity of MTHF can be improved by the synergistic effect of nickel and copper.

[0068] In this regard, in an embodiment of the present invention, it was confirmed that the conversion rate to MTHF increased when a bimetallic catalyst containing both nickel and copper was used compared to a catalyst manufactured by supporting nickel and copper on the same acid support.

[0069] In the present invention, the nickel and copper may be included in an amount of 10 to 40 wt%, preferably 15 to 30 wt%, based on the total weight of the catalyst, and at this time, the weight ratio of nickel and copper may be 4:1 to 1:4, preferably 2:1 to 1:2.

[0070] In the present invention, the MTHF selectivity can be effectively improved in a hydrogenation dehydration reaction for MTHF synthesis through the interaction of nickel and copper in a catalyst and the use of an acid support, and the MTHF selectivity can be maximized through the control of the type and composition of the support.

[0071] Therefore, the catalyst of the present invention can be usefully used in MTHF synthesis reactions using hydrogenation and dehydration reactions. When the catalyst is applied to the MTHF production method of the present invention, the catalyst can be used in an amount of 0.05 to 1 g, preferably 0.1 to 0.3 g, per 1 mL of reactant.

[0072] The catalyst for MTHF production of the present invention can be prepared through an impregnation method. Specifically, the catalyst of the present invention can be prepared through the steps of mixing and stirring a nickel salt and a copper salt on an acid support; and drying, calcining, and reducing the mixture after stirring to form a catalyst in which nickel and copper are supported on the acid support.

[0073] The above nickel salt is a precursor of nickel supported on a catalyst, and may be one or more selected from the group consisting of nickel nitrate, nickel sulfate, nickel chloride, and nickel carbonate, and may be used in the form of a hydrate.

[0074] The above copper salt is a precursor of copper supported on a catalyst, and may be one or more selected from the group consisting of copper chloride, copper nitrate, copper sulfate, and copper carbonate, and may be used in the form of a hydrate.

[0075] The above acid support is commercially available or can be prepared using a sol-gel method.

[0076] Specifically, when the acid support comprises two or more metal oxides, the acid support can be manufactured through a step of stirring each metal salt solution and adding an acid to form a sol; a step of drying the sol to obtain a xerogel; and a step of pulverizing and calcining the xerogel. In the manufacturing method, the xerogel means a dry gel from which the liquid has been removed, and the metal salt can be an alkoxide salt of the metal, such as an ethoxide, propoxide, or butoxide of the metal.

[0077] For example, when preparing a catalyst containing aluminum oxide and zirconium oxide as the acid support, the weight ratio of aluminum alkoxide and zirconium alkoxide in the metal salt solution can be adjusted to 1:1 to 10:1, preferably 2:1 to 6:1, and specifically 3:1 to 5:1. When using a catalyst prepared by adjusting the ratio of aluminum oxide and zirconium oxide in the acid support as described above, hydrogenation and dehydration reactions can be effectively promoted and the selectivity of MTHF can be improved.

[0078] In this regard, in an embodiment of the present invention, an experiment was conducted by controlling the weight ratio of aluminum isopropoxide and zirconium butoxide when preparing an acid support containing both aluminum oxide and zirconium oxide. As a result, it was confirmed that a catalyst including an acid support prepared using about 11 g of zirconium alkoxide per 42 g of aluminum alkoxide had a higher conversion rate to MTHF than a catalyst using a support containing only aluminum oxide. Through this, it was confirmed that MTHF selectivity can be maximized by mixing aluminum oxide and zirconium oxide as an acid support and controlling their ratio.

[0079] The above acid support and nickel salt and copper salt are mixed in a solution phase. At this time, the solvent of the solution may be at least one selected from the group consisting of water (distilled water), acetone, alcohol, ethyl acetate, hexane, heptane, toluene, dichloromethane, tetrahydrofuran, acetonitrile, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, dimethyl oxalate, and methylpyrrolidone, and preferably distilled water. In addition, the stirring of the solution may be performed for 1 to 24 hours, preferably 6 to 18 hours.

[0080] Once the above mixed solution is prepared, a step of drying it to obtain a solid sample is performed.

[0081] The above drying can be performed using known techniques and devices such as an oven, hot air, constant temperature and humidity, and microwave, and can be performed at a temperature of 60 to 150°C, preferably 100 to 120°C, to completely remove the solvent.

[0082] After evaporating all the solvent through the above drying process, a step of calcining the solid sample at high temperature is performed. The calcination can be performed while increasing the temperature under conditions of 350 to 600°C, preferably 400 to 550°C. At this time, the heating rate can be 2 to 8°C / min, preferably 4 to 6°C / min, and the total calcination time can be 2 to 6 hours, preferably 3 to 5 hours. Thereafter, a catalyst can be obtained through a reduction process at 400 to 800°C for 30 minutes to 5 hours.

[0083] The catalyst manufactured in this way has a structure in which nickel and copper are supported on an acid support, and can effectively improve MTHF selectivity in an MTHF synthesis reaction by controlling the acid site according to the interaction between nickel and copper in the catalyst and the composition of the acid support.

[0084]

[0085] Example

[0086]

[0087] The present invention is described in more detail through the following examples. However, these examples are intended to illustrate some experimental methods and configurations of the present invention, and the scope of the present invention is not limited to these examples.

[0088]

[0089] Manufacturing Example 1: Manufacturing of a catalyst using nickel, copper, and aluminum oxide

[0090]

[0091] According to the method illustrated in Fig. 2, a NiCu / Al2O3 catalyst was manufactured by a wet impregnation method using nickel and copper, which are non-precious metal materials, and aluminum oxide.

[0092] 10g of Al2O3 and 100mL of distilled water used as a support were stirred at 350rpm, and at the same time, 10% by weight of nickel nitrate hexahydrate (Ni(NO3) 2· 6H2O) 6.2g and copper chloride dihydrate (CuCl 2· 2H2O) was dissolved and stirred for 12 hours. After stirring, the solution was covered with aluminum foil, perforated, and dried at 110°C for 12 hours. The dried sample was calcined at 500°C for 4 hours at a ramping rate of 5°C / min. After that, a 10% hydrogen / nitrogen mixed gas was reduced at 600°C for 2 hours at a flow rate of 30 mL / min and a ramping rate of 10°C / min to obtain a NiCu / Al2O3 catalyst.

[0093]

[0094] Manufacturing Example 2: Manufacturing of a catalyst using nickel, copper, and aluminum oxide / zirconium oxide.

[0095]

[0096] According to the method shown in Fig. 3, an acid support was prepared by a sol-gel method using Al2O3 and ZrO2, and a catalyst was prepared using the same.

[0097] 4.2 g of aluminum isopropoxide was dissolved in 250 mL of ethanol, and 102.9 mL of zirconium(IV) n-butoxide (1.049 g / mL) was added and stirred for 30 minutes. 13.5 mL of nitric acid was slowly added little by little to the stirred solution while stirring, and the mixture was aged at room temperature for 12 hours after the addition was completed. The sol formed by the aged solution was dried at 120°C for 10 hours to form a xerogel. The xerogel was finely ground into powder and calcined at 300°C for 2 hours to obtain an Al2O3_ZrO2 support.

[0098] Using the method of Manufacturing Example 1, a NiCu / Al2O3_ZrO2 catalyst was manufactured using the Al2O3_ZrO2 support instead of Al2O3. The catalyst manufactured by the above method is denoted as NiCu / Al2O3_ZrO2(1), and in the following experimental examples, the ratio of Al2O3 and ZrO2 in the acid support was adjusted by multiplying Al2O3 by n times and ZrO2 by 1 / n times according to the value (n) indicated in parentheses based on this.

[0099]

[0100] Synthesis Example 1: MTHF Synthesis Reaction Using a Batch Reactor

[0101]

[0102] The reaction was carried out in a batch reactor using furfural and levulinic acid as reactants and 2-propanol as the reaction solvent. 1 g of catalyst was used per batch, and the solvent and reactants were used in a ratio of 45 mL of solvent to 5 mL of reactant.

[0103] Before the reaction began, the reactor was purged with argon gas (4 bar) to replace any remaining inert gas. The reactor was then filled with hydrogen gas (20 bar), and the reaction was performed at 200°C and 500 rpm. After the reaction was complete, the product obtained from the disassembled reactor was filtered to remove impurities and analyzed using HPLC (High Performance Liquid Chromatography) (Shimadzu SCL-40).

[0104] RID-20A was used as the HPLC analysis detector, Agilent's PL-1170-6830 was used as the column, and HPLC Water / 0.005M H2SO4 was used as the analysis solvent.

[0105]

[0106] Synthesis Example 2: MTHF Synthesis Reaction Using a Continuous Reactor

[0107]

[0108] The reaction was carried out in a continuous reactor using furfural and levulinic acid as reactants and 2-propanol as a reaction solvent. The solvent and reactants were used in a ratio of 45 mL of solvent to 5 mL of reactant.

[0109] The continuous reactor consisted of a three-layer structure, with 8 g of glass beads in the lower part, 5 g of NiCu / Al2O3 catalyst in the center, and 3 g of glass beads in the upper part. At this time, the reaction was carried out with WHSV set to 2 (0.2 mL / min), and reduction was performed once more at 400°C for 1 hour using hydrogen, and the reaction was carried out for 12 hours under the conditions of 250°C and 30 bar of hydrogen. The product after the reaction was analyzed by HPLC under the same conditions and environment as the batch method.

[0110]

[0111] Experimental Example 1: Analysis of the physicochemical properties of the catalyst

[0112]

[0113] The surface area, pore volume, and pore diameter of the catalyst manufactured according to the method of Manufacturing Example 1 were measured, and the results are shown in Table 1 below. In addition, the physicochemical properties were analyzed through the nitrogen adsorption isotherm, XRD analysis, and TEM images of FIGS. 4 to 6.

[0114]

[0115] Catalyst surface area (m) 2 / g)Pore volume (cm) 3 / g)Pore diameter (nm)NiCu / Al2O3137.50.395.2

[0116]

[0117] In addition, the surface area, pore volume, and pore diameter of the catalyst manufactured with the composition shown in Table 2 below according to the method of Manufacturing Example 2 were measured, and the results are shown together in Table 2. In addition, the physicochemical properties were analyzed through the nitrogen adsorption isotherm, XRD analysis, and TEM images of FIGS. 7 to 9.

[0118]

[0119] Catalyst surface area (m) 2 / g)Pore volume (cm) 3 / g) Pore diameter (nm)NiCu / Al2O31390.267.36NiCu / Al2O3_ZrO2(10)1360.195.59NiCu / Al2O3_ZrO2(7)1130.238.19NiCu / Al2O3_ZrO2(5)75.80.2010.95NiCu / Al2O3_ZrO2(3.5)30.80.1519.95NiCu / Al2O3_ZrO2(1)11.80.0827.01NiCu / ZrO210.80.1036.34

[0120]

[0121] Experimental results show that the surface area of ​​the NiCu / Al2O3 catalyst is 137 m 2 100m as / g 2 / g higher than that, in the NiCu / Al2O3_ZrO2 catalyst using Al2O3_ZrO2 support, the surface area decreased as the content of ZrO2 increased.

[0122] In addition, it was confirmed that a catalyst having a mesoporous form corresponding to Type IV was synthesized through the nitrogen adsorption isotherm, and in the XRD (X-Ray Diffraction) pattern, after Ni and Cu metals were supported on the support Al2O3 and Al2O3_ZrO2, a Ni-Cu alloy peak that could be confirmed with the naked eye was generated, confirming that the catalyst was successfully synthesized.

[0123] Additionally, the crystal structure analysis of the catalyst through transmission electron microscopy (TEM) images confirmed that Ni and Cu metals were successfully supported on the support Al2O3 and Al2O3_ZrO2.

[0124]

[0125] Experimental Example 2: Analysis of the acidity of the catalyst according to the acid ratio of the support.

[0126]

[0127] A catalyst was manufactured using the method of the above manufacturing example 2, but by adjusting the ratio of Al2O3 and ZrO2, and the acidity of the synthesized catalyst was confirmed from the ammonia temperature-elevated desorption analysis (NH3-TPD) results of FIG. 10, and the results are shown in Table 3 below.

[0128]

[0129] Catalytic weak acid NH3(des)(mmol g -1 ) Neutral acid NH3(des)(mmol g -1 ) Strong acid NH3(des)(mmol g -1 )Total acidity (mmol g) -1)NiCu / Al2O30.0630.3710.4300.864NiCu / Al2O3_ZrO2(10)0.0390.2740.5340.847NiCu / Al2O3_ZrO2(7)0.0680.3480.4760.892NiCu / Al2O3_ZrO2(5) 0.0570.3780.4870.922NiCu / Al2O3_ZrO2(3.5)0.0210.1400.5190.680NiC u / Al2O3_ZrO2(1)0.0020.0520.3300.384NiCu / ZrO20.0110.0970.3480.456

[0130]

[0131] The experimental results showed that as the content of ZrO2 in the support increased, the total acidity decreased, and this allowed us to confirm the change in conversion rate according to acidity when performing the MTHF synthesis reaction using each catalyst.

[0132]

[0133] Experimental Example 3: Analysis of MTHF Conversion Rate According to Reactant Ratio

[0134]

[0135] An MTHF synthesis reaction was performed in a batch reactor using a catalyst manufactured by the method of Manufacturing Example 1, but the reaction was performed by changing the composition of the reactants as shown in Table 4 below, and the conversion rate (%) and selectivity (%) were compared.

[0136]

[0137] Reaction conditionsCatalyst (powder)Reactant conversionFOL selectivityTHFOL selectivityGVL selectivityMF selectivity1,4-PDO selectivityMTHF selectivityFURNiCu / Al2O3100.010.056.07.002.00-25.0LANiCu / Al2O3100.0-----16.0FUR+LA(7:1)NiCu / Al2O310043.014.04.00-39.0FUR+LA(4:1)NiCu / Al2O3100.0-25.015.05.00-55.0FUR+LA(3:2 )NiCu / Al2O3100.0-22.028.04.00-46.0FUR+LA(1:1)NiCu / Al2O3100.0-16.042.06.00-36.0FUR +LA(2:3)NiCu / Al2O3100.0-13.050.04.00-33.0FUR+LA(1:4)NiCu / Al2O3100.0-17.054.0--29.0

[0138]

[0139] Experimental results showed that when furfural and levulinic acid were used as a mixture as reactants, the conversion rate was more than twice as high as when they were used alone. This indicates that during MTHF synthesis, the reaction with furfural and the reaction with levulinic acid coexist and participate in the MTHF conversion process, thereby enhancing reaction efficiency.

[0140] In addition, as a result of the experiment in which the ratio of furfural and levulinic acid in the reactants was adjusted to 7:1, 4:1, 3:2, 1:1, 2:3, and 1:4, the MTHF conversion rate increased as the ratio of furfural increased up to 4:1, and when the ratio of furfural was further increased to 7:1, the conversion rate decreased again.

[0141] From these results, it was confirmed that the MTHF conversion rate was improved by preventing the formation of gamma-valerolactone (GVL) from levulinic acid due to the predominant presence of furfural in the reactants, but this effect was somewhat reduced when the amount of furfural was too large.

[0142]

[0143] Experimental Example 4: Analysis of MTHF Conversion Rate by Catalyst Type

[0144]

[0145] An MTHF synthesis reaction was performed in a batch reactor using a catalyst manufactured by the method of Manufacturing Example 1. However, the reaction was performed by changing the catalyst as shown in Table 5 below, and the conversion rate (%) and selectivity (%) were compared.

[0146]

[0147] Reaction conditionsCatalyst (powder)Reactant conversionFOL selectivityTHFOL selectivityGVL selectivityMF selectivity1,4-PDO selectivityMTHF selectivityFUR+LA(4:1)NiCu / Al2O3100.0-25.015.05.00-55.0FUR+LA(4:1)Ni / Al2O3100.0-48.010.02.00-36.0FUR+LA(4:1)Cu / Al2O3100.0-33.018.021.0-28.0

[0148]

[0149] When the ratio of furfural and levulinic acid in the reactants was 4:1 and Ni / Al2O3 or Cu / Al2O3 was used instead of NiCu / Al2O3 as a catalyst, the conversion rate to MTHF was 36.0% or 28.0%, respectively, when a catalyst supporting only nickel or copper was used, but it was confirmed that the conversion rate greatly increased to 55.0% when a catalyst supporting both nickel and copper was used.

[0150]

[0151] Experimental Example 5: Analysis of MTHF Conversion Rate According to Reaction Conditions

[0152]

[0153] Using the catalyst manufactured by the method of Manufacturing Example 1, an MTHF synthesis reaction was performed in a batch reactor, but the reaction pressure and temperature were changed as shown in Table 6 below, and the conversion rate (%) and selectivity (%) were compared. In addition, the conversion rate over time was confirmed under conditions where the ratio of furfural and levulinic acid was 1:1, and the results are shown in a graph in Figure 11.

[0154]

[0155] Reaction ConditionsCatalyst (Powder)Reactant ConversionFOL SelectivityTHFOL SelectivityGVL SelectivityMF Selectivity1,4-PDO SelectivityMTHF SelectivityFUR+LA (4:1)NiCu / Al2O3100.0-25.015.05.00-55.0FUR+LA(4:1) - 10 barNiCu / Al2O3100.0-37.08.0035.0-20.0FUR+LA(4:1) - 30 barNiCu / Al2O3100.0-24.011.0--65.0FUR+LA(4:1) - 150℃NiCu / Al2O3100.016.037.0-15.0-27.0FUR+LA(4:1) - 250℃NiCu / Al2O3100.0-38.0---62.0

[0156]

[0157] As a result of the above experiment, it was confirmed that when the existing reaction temperature (200℃) was changed to 250℃, the conversion rate to MTHF increased to 62.0%, and when the existing reaction pressure (20 bar of hydrogen) was increased to 30 bar, the conversion rate to MTHF increased to 65.0%. Based on these results, it was confirmed that the reaction was more active under conditions of higher temperature and pressure.

[0158] In addition, when furfural and levulinic acid were used in a 1:1 ratio and the conversion rate according to the reaction time was compared, it was confirmed that as the reaction time increased, intermediates (furfuryl alcohol, methyl furan, etc.) decreased, and the conversion rate to the final target product, MTHF, improved.

[0159]

[0160] Experimental Example 6: Analysis of MTHF Conversion Rate According to Reaction Solvent

[0161]

[0162] An MTHF synthesis reaction was performed in a batch reactor using a catalyst manufactured by the method of Manufacturing Example 1, but the reaction solvent was changed as shown in Table 7 below to proceed with the reaction, and the conversion rate (%) and selectivity (%) were compared.

[0163]

[0164] Reaction ConditionsCatalyst (Powder)Reactant ConversionFOL SelectivityTHFOL SelectivityGVL SelectivityMF Selectivity1,4-PDO SelectivityMTHF SelectivityFUR+LA(4:1)NiCu / Al2O3100.0-25.015.05.00-55.0FUR+LA(4:1) - GVLNiCu / Al2O3100.0--50.0-32.018.0FUR+LA(4:1) - TolueneNiCu / Al2O3100.0-12.010.0-6.0072.0FUR+LA(4:1) - CPMENiCu / Al2O372.0-10.012.0-11.039.0FUR+LA(4:1) - MIBKNiCu / Al2O350.0-7.008.004.009.0022.0

[0165]

[0166] As a result of the experiment, when the reaction was carried out using GVL, toluene, CPME, or MIBK instead of 2-propanol, which was used as the existing reaction solvent, the conversion rate to MTHF was the highest at 72% when toluene was used, and in the case of GVL, it was confirmed that complete conversion to MTHF did not occur under the reaction conditions due to its thermal stability.

[0167]

[0168] Experimental Example 7: Conversion Rate Analysis According to Reaction Conditions

[0169]

[0170] An MTHF synthesis reaction was performed in a batch reactor using the catalyst prepared by the sol-gel method of Manufacturing Example 2. The composition of the reactants and the type of catalyst were adjusted as shown in Table 8 below, and the conversion rate (%) and selectivity (%) were compared in each reaction.

[0171]

[0172] Reaction conditionsCatalyst (powder)Reactant conversionTHFOL selectivityGVL selectivityMF selectivity1,4-PDO selectivityMTHF selectivityFURNiCu / Al2O3100.052.06.00--42.0FURNiCu / Al2O3_ZrO2(10)100.042.06.00-3.0049.0FURNiCu / Al2O3_ZrO2(7)100.041.08.00-22.029.0FURNiCu / Al 2O3_ZrO2(5)100.035.010.0-34.021.0FURNiCu / Al2O3_ZrO2(3.5)100.026.09 .00-49.016.0FURNiCu / Al2O3_ZrO2(1)100.022.08.00-56.014.0FURNiCu / ZrO2 100.017.06.00-65.012.0LANiCu / Al2O3100.0-67.0--33.0LANiCu / Al2O3_ZrO 2(10)100.0-59.0--41.0LANiCu / Al2O3_ZrO2(7)100.0-76.0--24.0LANiCu / Al2 O3_ZrO2(5)100.0-82.0--18.0LANiCu / Al2O3_ZrO2(3.5)100.0-87.0--13.0LA NiCu / Al2O3_ZrO2(1)100.0-90.0--10.0LANiCu / ZrO2100.0-92.0--8.00FUR+LA (4:1)NiCu / Al2O3100.027.024.02.00-47.0FUR+LA (4:1)NiCu / Al2O3_ZrO2(10)100.019.021.02.003.0057.0FUR+LA (4:1)NiCu / Al2O3_ZrO2(7)100.021.022.02.0017.038.0FUR+LA (4:1)NiCu / Al2O3_ZrO2(5)100.017.017.01.0035.030.0FUR+LA (4:1)NiCu / Al2O3_ZrO2(3.5)100.014.016.01.0048.021.0FUR+LA (4:1)NiCu / Al2O3_ZrO2(1)100.012.013.02.0053.020.0FUR+LA (4:1)NiCu / ZrO2100.011.013.0-59.017.0FUR+LA (1:4)NiCu / Al2O3100.05.0057.0--38.0FUR+LA (1:4)NiCu / Al2O3_ZrO2(10)100.03.0054.0--43.0FUR+LA (1:4)NiCu / Al2O3_ZrO2(7)100.08.0060.0--32.0FUR+LA (1:4)NiCu / Al2O3_ZrO2(5)100.010.062.0-1.0027.0FUR+LA (1:4)NiCu / Al2O3_ZrO2(3.5)100.012.065.0-3.0020.0FUR+LA (1:4)NiCu / Al2O3_ZrO2(1)100.012.069.0-1.0015.0FUR+LA (1:4)NiCu / ZrO2100.012.072.0-5.0011.0.

[0173]

[0174] According to the ammonia temperature-elevated desorption analysis results of Experimental Example 2, it was confirmed that as the content of ZrO2 in the support increased, the acidity of the catalyst decreased. When these acidity experimental results were combined with the reaction results above, it was confirmed that the conversion rate to MTHF tended to increase as the acidity increased.

[0175] In addition, when furfural and levulinic acid were mixed and used as reactants and the proportion of furfural was higher, the highest conversion rate to MTHF was achieved at 57.0%. Accordingly, it was confirmed that more effective conversion to MTHF was possible when a mixed form of furfural and levulinic acid was used as a reactant in both the NiCu / Al2O3 catalyst synthesized by the wet impregnation method and the NiCu / Al2O3_ZrO2 catalyst synthesized by the sol-gel method.

[0176]

[0177] Experimental Example 8: MTHF Synthesis Using a Continuous Reactor

[0178]

[0179] Using the catalyst manufactured according to Manufacturing Example 1, and using furfural and levulinic acid as reactants in a 4:1 ratio, the reaction was carried out in a continuous reactor at 250°C and 30 bar of hydrogen for 12 hours. For comparison, the reaction was carried out in a continuous reactor using furfural or levulinic acid alone as reactants, and the conversion (%) and selectivity (%) of each reaction were compared and are shown in Table 9 below.

[0180]

[0181] Reaction conditions Catalyst (powder) Reactant conversion FOL selectivity THF selectivity GVL selectivity MF selectivity 1,4-PDO selectivity MTHF selectivity FUR NiCu / Al2O3 100.0 45.0 33.0 10.0--12.0 LANiCu / Al2O3 87.0--79.0--21.0 FUR+LA(4:1) NiCu / Al2O3 FUR:100.0 LA:80.0 30.0 37.7 7.0 0--26.0

[0182]

[0183] The reaction results in a continuous reactor showed a lower conversion rate to MTHF than in a batch reactor. However, in a continuous reactor as well, it was confirmed that the conversion rate to MTHF was higher when a mixed form of reactants was used than when furfural or levulinic acid were used independently.

[0184]

[0185] While specific aspects of the present invention have been described in detail above, it will be apparent to those skilled in the art that these specific descriptions merely represent preferred embodiments and do not limit the scope of the present invention. Therefore, the substantial scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing 2-methyltetrahydrofuran, comprising the step of obtaining 2-methyltetrahydrofuran (MTHF) by hydrogenating and dehydrating a furfural compound and a levulinic acid compound.

2. In paragraph 1, A method for producing 2-methyltetrahydrofuran, wherein the volume ratio of the furfural compound and the levulinic acid compound is 1:5 to 10:

1.

3. In paragraph 1, A method for producing 2-methyltetrahydrofuran, wherein the above reaction is performed under a pressure of 10 to 50 bar.

4. In paragraph 1, A method for producing 2-methyltetrahydrofuran, wherein the above reaction is performed at a temperature of 150 to 400°C.

5. In paragraph 1, A method for producing 2-methyltetrahydrofuran, wherein the solvent used in the above reaction comprises at least one selected from the group consisting of ethanol, propanol, butanol, toluene, cyclopentyl methyl ether (CPME), gamma valerolactone (GVL), and methyl isobutyl ketone (MIBK).

6. In paragraph 1, A method for producing 2-methyltetrahydrofuran, wherein the above reaction is carried out in the presence of an acid support and a catalyst comprising nickel and copper metals supported on the acid support.

7. In paragraph 1, A method for producing 2-methyltetrahydrofuran, wherein the above reaction is performed in a batch reactor or a continuous reactor.

8. In paragraph 1, The above method for producing 2-methyltetrahydrofuran is A step of converting a portion of levulinic acid in a woody biomass containing furfural and levulinic acid into gamma valerolactone; and A step of reacting the above furfural and residual levulinic acid to obtain 2-methyltetrahydrofuran. A method for producing 2-methyltetrahydrofuran, comprising:

9. A catalyst for producing 2-methyltetrahydrofuran, comprising an acid support and nickel and copper metals supported on the acid support.

10. In paragraph 9, A catalyst for producing 2-methyltetrahydrofuran, wherein the acid support comprises at least one selected from the group consisting of aluminum oxide, zirconium oxide, zinc oxide, titanium oxide, magnesium oxide, cerium oxide, and lanthanum oxide.

11. A step of mixing and stirring nickel salt and copper salt on a mountain support; and A step of forming a catalyst in which nickel and copper are supported on an acid support by drying, calcining, and reducing the mixture in which the stirring is completed. A method for producing a catalyst for producing 2-methyltetrahydrofuran, comprising:

12. In paragraph 11, The above mountain support, A step of stirring a metal salt solution and adding an acid to form a sol; A step of drying the above solution to obtain a xerogel; and A step of crushing and calcining the above zero gel to obtain an acid support. A method for producing a catalyst for producing 2-methyltetrahydrofuran, the catalyst being manufactured through.

13. In paragraph 12, A method for producing a catalyst for producing 2-methyltetrahydrofuran, wherein the metal salt solution contains aluminum alkoxide and zirconium alkoxide in a weight ratio of 1:1 to 10:

1.

14. In paragraph 11, A method for producing a catalyst for producing 2-methyltetrahydrofuran, wherein the drying is performed at a temperature of 60 to 150°C.

15. In paragraph 11, A method for producing a catalyst for producing 2-methyltetrahydrofuran, wherein the above-mentioned calcination is performed at a temperature of 350 to 600°C.

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