Method for preparing 2, 5-furandimethanol through catalytic conversion of 5-hydroxymethylfurfural

Abstract

The invention belongs to the technical field of fine chemical engineering, and discloses a method for preparing 2, 5-furandimethanol through hydrogenation of 5-hydroxymethylfurfural by using a metal oxide catalyst, which comprises the following steps: filling 5-hydroxymethylfurfural, a catalyst and an alcohol solvent into a reaction kettle, and carrying out closed reaction under the conditions of high temperature and inert gas to obtain the 2, 5-furandimethanol. 2, 5-furandimethanol is added; the catalyst is a zirconium oxide and copper oxide composite catalyst loaded on silicon oxide. According to the method, isopropanol is adopted as a solvent and a hydrogen donor, and 5-hydroxymethylfurfural is efficiently catalyzed under the catalytic action of the composite catalyst silicon oxide carrier loaded zirconium oxide and copper oxide, so that 2, 5-furandimethanol with higher yield can be obtained; the synthesis raw materials are simple and easy to obtain, the reaction system is simple and safe, the preparation method is simple, the preparation cost is low, the economical efficiency is high, and important practical value and wide application prospects are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemicals, and specifically relates to a method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural, and more specifically to a method for preparing 2,5-furan dimethanol by hydrogenating 5-hydroxymethylfurfural by using a supported metal oxide composite catalyst. Background Art

[0002] 2,5-Furan dimethanol is obtained by one-step hydrogenation of the biomass platform compound 5-hydroxymethylfurfural. It is used in the preparation and research of polyester, polyether and polyurethane materials, softeners, adhesives and synthetic drug molecules. It is a high value-added diol. In recent years, precious metal-based catalysts (ruthenium-based, palladium-based, iridium-based, platinum-based, etc.) have shown superior catalytic performance and can catalyze the hydrogenation of 5-hydroxymethylfurfural under relatively mild conditions to obtain 2,5-furan dimethanol with a relatively high yield, but their development and utilization are limited due to their high prices. Non-precious metal catalysts are inexpensive and can save costs in industrial production. The active ingredients in non-precious metal catalysts usually include zirconium, copper, nickel, etc. Most copper-based and nickel-based catalysts use hydrogen as hydrogen donors, and some catalysts need to be reduced in a hydrogen atmosphere in a tubular furnace before the reaction. Copper-based catalysts have high reactivity to C=O and CO bonds, and low reactivity to C=C and CC bonds, and are one of the best materials for selective hydrogenation. Zirconium-based catalysts have abundant acid sites and can effectively catalyze the reaction. Their overly strong acid sites catalyze the further etherification of 2,5-furan dimethanol, reducing the selectivity of the product. Therefore, the preparation of non-precious metal catalysts with an appropriate amount of Lewis acid sites and alcohols as hydrogen donors meets the requirements of green and sustainable chemical development. Summary of the invention

[0003] The object of the present invention is to overcome the defects of the prior art and provide a method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural, which method comprises the following steps:

[0004] 5-Hydroxymethylfurfural, a catalyst and an alcohol solvent are placed in a reaction kettle, and a closed reaction is carried out under high temperature and inert gas conditions to obtain 2,5-furan dimethanol; the catalyst is a composite catalyst of zirconium oxide and copper oxide supported on silicon oxide.

[0005] The alcohol solvent is used as a hydrogen donor, and the zirconium oxide and copper oxide complex supported on silicon oxide is used as a catalyst to catalyze 5-hydroxymethylfurfural to prepare 2,5-furan dimethanol under high temperature conditions.

[0006] In a preferred embodiment of the present invention, the method for preparing the catalyst comprises the following steps:

[0007] The zirconium salt and the copper salt are dissolved in a solvent, and a silicon oxide carrier is added and evenly dispersed in the solvent; the solvent is removed to obtain a solid, and the solid is calcined in high-temperature air to obtain the catalyst.

[0008] The zirconium salt, copper salt and silicon oxide carrier are dispersed together in a solvent and mixed and dispersed evenly, and then the solvent is removed, and zirconium and copper are adsorbed on the surface of the carrier in the form of ions. After high-temperature calcination, a catalyst is obtained, and the catalyst is a zirconium and copper composite oxide supported on a silicon oxide carrier.

[0009] In a preferred embodiment of the present invention, the solvent can be at least one of methanol, ethanol or water; the method for removing the solvent is heating and drying, and the heating temperature is the boiling point of the solvent - boiling point + 30°C.

[0010] In another preferred embodiment of the present invention, the method for preparing the catalyst comprises the following steps:

[0011] 1) dissolving a zirconium salt in a first solvent and removing the first solvent;

[0012] 2) then dissolving the zirconium salt and copper salt in a second solvent, and adding a silicon oxide carrier and dispersing it evenly in the second solvent;

[0013] 3) removing the second solvent to obtain a solid, and calcining the solid in high-temperature air to obtain the catalyst.

[0014] In a preferred embodiment of the present invention, the alcohol solvent is isopropanol; the reaction temperature is 120-170° C.; and the reaction time is 3-7 hours.

[0015] In a preferred embodiment of the present invention, the concentration of 5-hydroxymethylfurfural in alcohol solvent is 0.1-5wt%; the mass ratio of the catalyst to 5-hydroxymethylfurfural is (0.5-2):1; and the silicon oxide carrier is nano silicon oxide.

[0016] More preferably, the nanoparticle size of the silicon oxide is 10 to 20 nm.

[0017] In a preferred embodiment of the present invention, the mass ratio of zirconium oxide to copper oxide in the catalyst is 1:2-3:1; the mass ratio of the total mass of zirconium oxide and copper oxide to the mass of the carrier is (0.3-0.5):1.

[0018] In a preferred embodiment of the present invention, the zirconium salt is a nitrate, and the copper salt is a nitrate.

[0019] In a preferred embodiment of the present invention, the solvent can be at least one of methanol, ethanol or water; the method for removing the solvent is heating and drying, and the heating temperature is the boiling point of the solvent to - boiling point + 30°C.

[0020] In a preferred embodiment of the present invention, the first solvent can be methanol or ethanol, and the second solvent is water; the method for removing the first solvent is heating and drying, and the heating temperature is the boiling point of the first solvent - the boiling point + 30°C; the method for removing the second solvent is heating and drying, and the heating temperature is the boiling point of the second solvent - the boiling point + 30°C.

[0021] Since the solubility of zirconium salt in alcohol solvents is higher than that in water, the zirconium salt is pre-dispersed by a first alcohol solvent so that the first solvent alcohol molecules are adsorbed on the surface of the zirconium salt. The solubility of the zirconium salt adsorbed on the surface of the first solvent alcohol molecules in water is improved. Based on this, the zirconium salt, copper salt and silica carrier can be uniformly mixed in the aqueous phase, which is beneficial for the catalyst obtained after the removal of the second solvent and the calcination step to be a zirconium oxide and copper oxide composite metal oxide uniformly dispersed on the silica carrier.

[0022] In a preferred embodiment of the present invention, the calcination temperature is 300-600° C., and the calcination time is 3-10 h.

[0023] Through the design of the present invention, the present invention can at least achieve the following beneficial effects:

[0024] 1. The present invention provides a method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethyl furfural, wherein the synthetic raw materials are simple and easy to obtain, the preparation method is simple, the preparation cost is low, and the economy is strong. Compared with the prior art, the preparation method of the present invention is simpler, does not require the use of expensive natural resources or complex chemical reactions, reduces production costs, and improves economic benefits.

[0025] 2. The method of the present invention preferably uses an alcohol solvent, especially isopropanol, as a solvent and a hydrogen donor. The reaction system is relatively simple and safe, and under the synergistic effect of a suitable catalyst, a high yield of 2,5-furan dimethanol can be obtained. In the prior art, hydrogen needs to be used as a hydrogen donor, and reduction needs to be carried out in a tubular furnace hydrogen atmosphere before the reaction, which increases the complexity and cost of the process. The present invention avoids the use of hydrogen, reduces the danger and complexity of the operation, and improves the safety of the reaction.

[0026] 3. For the reaction system of the present invention, by selecting a catalyst with high catalytic efficiency, i.e., a composite catalyst of zirconium oxide and copper oxide supported on a silicon oxide carrier, a high yield of 2,5-furan dimethanol can be obtained. And by further adjusting the mass ratio of zirconium oxide, copper oxide, and silicon oxide carrier, the nanoparticle size of silicon oxide, etc. to adjust the active sites of the catalyst and adjust the reaction conditions, the yield of 2,5-furan dimethanol can be optimized. However, the active sites and acid sites of non-precious metal catalysts in the prior art are difficult to adjust, and it is difficult to prepare non-precious metal catalysts with an appropriate amount of Lewis acid sites. The present invention solves this problem, improves the activity and selectivity of the catalyst, and improves the yield of the product.

[0027] 4. The catalyst of the present invention does not need to be reduced during the catalytic process, which simplifies the process flow and reduces production costs. However, the non-precious metal catalysts in the prior art need to use hydrogen as a hydrogen donor during the catalytic process, and need to be reduced in a tubular furnace hydrogen atmosphere before the reaction, which increases the complexity and cost of the process. The present invention avoids this problem, improves production efficiency, and reduces production costs.

[0028] In summary, compared with the prior art, the present invention has the advantages of simple preparation method, mild reaction conditions, high catalyst activity, good selectivity, low production cost, etc., and has important practical value and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 : XRD patterns of the catalysts of Examples 1-6.

[0030] Figure 2 (ae): XPS spectra of the catalysts of Examples 1-6.

[0031] Figure 3 (ah): SEM images (ab) and EDS images (ch) of the catalysts of Examples 1-6. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below through examples.

[0033] In order to explain the technical content, structural features, achieved objectives and effects of the technical solution in detail, the following is a detailed description in conjunction with specific embodiments and accompanying drawings.

[0034] In the embodiment, the catalyst is z-ZC(x) / Yy, wherein Z represents zirconium oxide; C represents copper oxide; Y represents the composition of the supported catalyst; x represents the mass ratio of zirconium oxide to copper oxide, which is an absolute value; y represents the calcination temperature, in °C; z represents the mass ratio of the total mass of zirconium oxide and copper oxide to the mass ratio of the support, in mass percentage (wt%).

[0035] After the catalytic reaction in the embodiment is completed, the content of various substances in the sample is detected by gas chromatography, and the conversion rate (%) is calculated as follows: (1-(molar amount of raw materials remaining in the reaction product / molar amount of raw materials added before the reaction))*100% and the yield (%) is calculated as follows: (molar amount of product in the reaction product / molar amount of raw materials added before the reaction)*100%. The raw material is 5-hydroxymethylfurfural and the product is 2,5-furan dimethanol.

[0036] Examples 1-6

[0037] Preparation method of catalyst:

[0038] Accurately weigh 0.9293g Zr(NO3)4·5H2O and dissolve it in 5mL methanol. Stir the solution magnetically at 80℃ until all the methanol is evaporated, then add 0.4039g Cu(NO3)2·3H2O and 5mL ultrapure water. After fully dissolved, add 1g SiO2 with a particle size of 15nm. Let it stand overnight at room temperature, dry it in an oven at 80℃ for 8h, then take it out and grind it through a sieve. Finally, put it in a muffle furnace and calcine it at 350℃ for 5h at a heating rate of 10℃ / min to obtain a composite catalyst of zirconium oxide and copper oxide supported on silicon oxide (labeled as 40wt%-ZC(2) / SiO2-350). The mass ratio of ZrO2, CuO and carrier is 0.27:0.13:1 (the mass ratio of zirconium oxide and copper oxide is approximately 2 in absolute value). The catalyst is stored in a desiccator for later use.

[0039] pass Figure 1 The XRD characterization shows the morphology of the catalyst. Due to the presence of amorphous silicon dioxide, the XRD spectrum of the catalyst shows broad peaks around 15-30° (2θ); the broad peak at 2θ=30° indicates that zirconium oxide has not formed crystals and exists in an amorphous state, and no characteristic diffraction peaks other than SiO2 and ZrO2 appear. Figure 2 XPS characterization of the catalyst Figure 2 (a) It can be seen that the catalyst is composed of Si, O, Zr, and Cu; Figure 2 (b) shows the XPS spectrum of Zr3d. The strong peaks of the catalyst at 182.56 eV and 184.93 eV are attributed to the characteristic peaks of Zr3d5 / 2 and Zr3d3 / 2, respectively, indicating that the zirconium element exists in the form of highly oxidized Zr(IV). Figure 2 (c) shows the XPS spectrum of Cu2p. The 2p3 / 2 peak of Cu is located at 934.52 eV, and the 2p1 / 2 peak of Cu is located at 954.41 eV, accompanied by obvious satellite peaks, which correspond to the Cu 2+ The catalyst morphology was characterized by scanning electron microscopy (SEM). Figure 3As shown in (ab), the catalyst is approximately spherical in shape, and the particle size is about 15 nm. Figure 3 As shown in (cg), the catalyst element distribution diagram shows that the catalyst contains Zr, Cu, O, and Si elements and their distribution is relatively uniform. Figure 3 As shown in (h), the energy spectrum analysis shows that the catalyst contains zirconium, copper, silicon and oxygen, and no other impurity elements are produced.

[0040] Method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural:

[0041] 0.2 g of 5-hydroxymethylfurfural and 19.8 g of isopropanol solvent were added to a 50 mL autoclave, and then 0.2 g of catalyst (40 wt % -ZC (2) / SiO2-350) was added, the mass ratio of ZrO2, CuO and SiO2 carriers was 0.27:0.13:1), the air in the autoclave was replaced with nitrogen three times, the autoclave was closed, stirred at 500 rpm, heated to 120, 130, 140, 150, 160, 170 ° C and maintained for 5 h, the reaction was terminated and cooled at room temperature, the reaction mixture was separated, the supernatant was taken, standard solutions of 5-hydroxymethylfurfural and 2,5-furan dimethanol were prepared, and quantitative and qualitative analyses were performed using a gas chromatograph. The results are listed in Table 1, No. 1-6.

[0042] Examples 1-6 explore the effect of reaction temperature on catalytic activity. It can be seen that under the conditions of 120°C and 5h, the conversion rate of 5-hydroxymethylfurfural is 60.64%, and the yield of 2,5-furan dimethanol is 59.83%; under the conditions of 140°C and 5h, the conversion rate of 5-hydroxymethylfurfural is 97.22%, and the yield of 2,5-furan dimethanol is 90.35% (Example 3). It shows that increasing the reaction temperature can effectively promote the formation of the target product. When the reaction temperature is increased to 160°C and 170°C, the conversion rate increases slightly, but the yield gradually decreases. This may be due to the occurrence of other side reactions caused by the excessively high reaction temperature, which leads to a decrease in the yield of 2,5-furan dimethanol. Therefore, the optimal reaction temperature is 140-150°C.

[0043] Examples 7-10

[0044] The corresponding catalysts were prepared according to the catalyst preparation methods of Examples 1-6 for later use.

[0045] Method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural:

[0046] 0.2 g of 5-hydroxymethylfurfural and 19.8 g of isopropanol solvent were added to a 50 mL autoclave, and then 0.2 g of a catalyst (40 wt% -ZC (2) / SiO2-350) was added, the mass ratio of ZrO2, CuO, and carrier was 0.27:0.13:1), the air in the autoclave was replaced with nitrogen three times, the autoclave was closed, stirred at 500 rpm, heated to 140° C. and maintained for 3, 4, 6, and 7 hours, respectively, the reaction was terminated and cooled to room temperature, the reaction mixture was separated, the supernatant was taken, standard solutions of 5-hydroxymethylfurfural, 2,5-furan dimethanol, etc. were prepared, and quantitative and qualitative analyses were performed using a gas chromatograph. The results are listed in Table 1, No. 7-10.

[0047] Examples 7-10 explore the effect of reaction time on catalytic activity. It can be seen that under the conditions of 140°C and 3h, the conversion rate of 5-hydroxymethylfurfural is 64.28%, and the yield of 2,5-furan dimethanol is 49.63%; while under the conditions of 140°C and 5h (Example 3), the conversion rate of 5-hydroxymethylfurfural is increased to 97.22%, and the yield of 2,5-furan dimethanol is increased to 90.35%. When the reaction time is extended to 6h and 7h, the conversion rate increases slightly, but the yield gradually decreases. This may be due to the occurrence of other side reactions caused by the long reaction time, which leads to a decrease in the yield of diols. Therefore, the optimal reaction time is 5-7h.

[0048] Examples 11-14

[0049] The corresponding catalysts were prepared according to the catalyst preparation methods of Examples 1-6 for later use.

[0050] Method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural:

[0051] 0.2 g of 5-hydroxymethylfurfural and 19.8 g of isopropanol solvent were added to a 50 mL autoclave, and then 0.1 g, 0.15 g, 0.25 g and 0.3 g of catalyst (40 wt%-ZC(2) / SiO2-350) were added, the mass ratio of ZrO2, CuO and carrier was 0.27:0.13:1), the air in the autoclave was replaced with nitrogen three times, the autoclave was closed, stirred at 500 rpm, heated to 140° C. and maintained for 5 h, the reaction was terminated and cooled at room temperature, the reaction mixture was separated, the supernatant was taken, standard solutions of 5-hydroxymethylfurfural, 2,5-furan dimethanol and the like were prepared, and quantitative and qualitative analyses were performed using a gas chromatograph. The results are listed in Table 1, No. 11-14.

[0052] Examples 11-14 explore the effect of catalyst dosage on catalytic activity. It can be seen that under the conditions of 140°C and 5h, when the catalyst dosage is 0.1g, the 5-hydroxymethylfurfural conversion rate is 88.37%, and the 2,5-furan dimethanol yield is 79.84%; while the catalyst dosage is 0.2g, the 5-hydroxymethylfurfural conversion rate is 97.22%, and the 2,5-furan dimethanol yield is 90.35% (Example 3). When the catalyst dosage continues to increase to 0.3g, the conversion rate remains basically unchanged, but the yield gradually decreases. This may be due to the continuous increase in by-products of the reaction system, resulting in a decrease in the yield of 2,5-furan dimethanol. Therefore, the preferred catalyst dosage is 0.2-0.3g.

[0053] Examples 15-16

[0054] Preparation method of catalyst:

[0055] Accurately weigh 0.9293g Zr(NO3)4·5H2O and dissolve it in 5mL methanol. Stir the solution magnetically at 80℃ until all the methanol is evaporated, then add 0.4039g Cu(NO3)2·3H2O and 5mL ultrapure water. After fully dissolved, add 1g SiO2 with a particle size of 15nm. Let it stand overnight at room temperature, dry it in an oven at 80℃ for 8h, take it out and grind it through a sieve, and finally put it into a muffle furnace and calcine it at 450℃ and 550℃ for 5h at a heating rate of 10℃ / min, respectively, to obtain catalysts marked as 40wt%-ZC(2) / SiO2-450 and 40wt%-ZC(2) / SiO2-550, which are stored in a desiccator for later use.

[0056] Method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural:

[0057] 0.2 g of 5-hydroxymethylfurfural and 19.8 g of isopropanol solvent were added to a 50 mL autoclave, and then 0.2 g of catalyst (40 wt%-ZC(2) / SiO2-450, 40 wt%-ZC(2) / SiO2-550, the mass ratio of ZrO2, CuO and carrier was 0.27:0.13:1) was added. After replacing the air in the autoclave with nitrogen three times, the autoclave was closed, stirred at 500 rpm, heated to 140° C. and maintained for 5 h, the reaction was terminated and cooled at room temperature, the reaction mixture was separated, the supernatant was taken, and standard solutions of 5-hydroxymethylfurfural, 2,5-furan dimethanol and the like were prepared. Quantitative analysis and qualitative analysis were performed using a gas chromatograph. The results are listed in Table 1, No. 15-16.

[0058] Examples 15-16 explored the effect of calcination temperature on catalytic activity. It can be seen that when the calcination temperature is 350°C, the conversion rate of 5-hydroxymethylfurfural is 97.22% and the yield of 2,5-furan dimethanol is 90.35% (Example 3). As the calcination temperature increases, the substrate conversion rate and product yield both show a downward trend. Therefore, the optimal calcination temperature is 350°C.

[0059] Examples 17-21

[0060] Preparation method of catalyst:

[0061] A certain amount of Zr(NO3)4·5H2O was dissolved in 5mL of methanol. The solution was magnetically stirred at 80°C until all the methanol was evaporated, and then a certain amount of Cu(NO3)2·3H2O and 5mL of ultrapure water were added. After fully dissolved, 1g of SiO2 with a particle size of 15nm (obtained from commercial sources) was added. The mixture was allowed to stand overnight at room temperature, dried in an oven at 80°C for 8h, taken out and ground and sieved, and finally placed in a muffle furnace and calcined at 350°C for 5h at a heating rate of 10°C / min to obtain the products labeled as 27wt%-Z(2) / SiO2-350, 13wt%-C(1) / SiO2-350, 40wt%-ZC(0.5) / SiO2-350, 40wt%-ZC(1) / SiO2-3 50 and 40wt%-ZC(3) / SiO2-350 catalysts (adjust the added amounts of Zr(NO3)4·5H2O and Cu(NO3)2·3H2O to achieve a mass ratio of ZrO2, CuO and SiO2 carriers of 0.27:0:1, 0:0.13:1, 0.13:0.27:1, 0.20:0.20:1 or 0.30:0.10:1) and stored in a desiccator for later use.

[0062] Method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural:

[0063] 0.2 g of 5-hydroxymethylfurfural and 19.8 g of isopropanol solvent were added to a 50 mL autoclave, and then 0.2 g of catalyst (27 wt % -Z(2) / SiO2-350, 13 wt % -C(1) / SiO2-350, 40 wt % -ZC(0.5) / SiO2-350, 40 wt % -ZC(1) / SiO2-350 or 40 wt % -ZC(3) / SiO2-350 catalyst) was added, and the mass ratio of ZrO2, CuO and SiO2 carrier was 0.27:0:1, 0: 0.13:1, 0.13:0.27:1, 0.20:0.20:1 or 0.30:0.10:1), after replacing the air in the kettle with nitrogen three times, the reactor was sealed, stirred at a speed of 500 rpm, heated to 140°C and maintained for 5 hours, the reaction was terminated and cooled at room temperature, the reaction mixture was separated, the supernatant was taken, and standard solutions of 5-hydroxymethylfurfural and 2,5-furan dimethanol were prepared, and quantitative and qualitative analyses were performed using a gas chromatograph. The results are listed in Table 1, No. 17-21.

[0064] Examples 17-21 explore the effect of different metal oxide mass ratios on the catalytic activity of the catalyst. It can be seen that when the mass ratio of ZrO2 to CuO is approximately 2 (Example 3), the conversion rate of 5-hydroxymethylfurfural is 97.22%, and the optimal yield of 2,5-furan dimethanol is 90.35%.

[0065] Examples 22-23

[0066] Preparation method of catalyst:

[0067] A certain amount of Zr(NO3)4·5H2O was dissolved in 5mL of methanol, and the solution was magnetically stirred at 80°C until all the methanol was evaporated, and then a certain amount of Cu(NO3)2·3H2O and 5mL of ultrapure water were added. After fully dissolved, 1g of SiO2 with a particle size of 15nm was added. It was left to stand overnight at room temperature, dried in an oven at 80°C for 8h, taken out and ground and sieved, and finally placed in a muffle furnace and calcined at 350°C for 5h at a heating rate of 10°C / min to obtain catalysts 30wt%-ZC(2) / SiO2-350 (the total mass ratio of zirconium oxide and copper oxide to the carrier was 0.3:1) and 50wt%-ZC(2) / SiO2-350 (the total mass ratio of zirconium oxide and copper oxide to the carrier was 0.5:1), which were stored in a desiccator for later use.

[0068] Method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural:

[0069] 0.2 g of 5-hydroxymethylfurfural and 19.8 g of isopropanol solvent were added to a 50 mL autoclave, and then 0.2 g of catalyst (30 wt%-ZC(2) / SiO2-350, 50 wt%-ZC(2) / SiO2-350) was added, the mass ratios of ZrO2, CuO and carrier were 0.20:0.10:1 and 0.33:0.17:1, respectively). After replacing the air in the autoclave with nitrogen three times, the autoclave was closed, stirred at 500 rpm, heated to 140° C. and maintained for 5 h, the reaction was terminated and cooled at room temperature, the reaction mixture was separated, the supernatant was taken, standard solutions of 5-hydroxymethylfurfural, 2,5-furan dimethanol and the like were prepared, and quantitative and qualitative analyses were performed using a gas chromatograph. The results are listed in Table 1, No. 22-23.

[0070] Examples 22-23 investigated the effect of metal loading on catalytic activity. When the loading was 40 wt% (the total mass ratio of zirconium oxide to copper oxide and the carrier was 0.4:1) (Example 3), the conversion rate of 5-hydroxymethylfurfural was 97.22%, and the optimal yield of 2,5-furan dimethanol was 90.35%.

[0071] Examples 24-30

[0072] Preparation method of catalyst:

[0073] 0.9293 g Zr(NO3)4·5H2O was accurately weighed and dissolved in 5 mL methanol. The solution was magnetically stirred at 80°C until all the methanol was evaporated, and then 0.4039 g Cu(NO3)2·3H2O and 5 mL ultrapure water were added. After fully dissolved, 1 g of the carrier was added. The mixture was allowed to stand overnight at room temperature, dried in an oven at 80°C for 8 h, taken out and ground and sieved, and finally placed in a muffle furnace and calcined at 350°C for 5 h at a heating rate of 10°C / min to obtain a catalyst marked as 40 wt%-ZC(2) / Y-350 (Y represents the carrier, which are USY, SBA-15, MCM41 (full, indicating full silicon), MCM41 (25, indicating a silicon-aluminum ratio of 25), Beta-25, Beta-40, and ZSM-5, all molecular sieves), which were stored in a desiccator for later use.

[0074] Method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural:

[0075] 0.2 g of 5-hydroxymethylfurfural and 19.8 g of isopropanol solvent were added to a 50 mL autoclave, and then 0.2 g of a catalyst 40 wt%-ZC(2) / Y-350 was added. After replacing the air in the autoclave with nitrogen three times, the autoclave was sealed, stirred at 500 rpm, heated to 140° C. and maintained for 5 h. After the reaction was terminated, the mixture was cooled to room temperature, the reaction mixture was separated, the supernatant was taken, and standard solutions of 5-hydroxymethylfurfural, 2,5-furan dimethanol, etc. were prepared. Quantitative and qualitative analyses were performed using a gas chromatograph. The results are listed in Table 1, No. 24-30.

[0076] Examples 24-30 explore the effect of catalyst carrier on catalytic activity. It can be seen that when the carrier is SiO2, the conversion rate of 5-hydroxymethylfurfural is 97.22% and the yield of 2,5-furan dimethanol is 90.35% (Example 3). Therefore, the best catalyst carrier is SiO2.

[0077] Examples 31-34

[0078] Preparation method of catalyst:

[0079] Accurately weigh 0.9293g Zr(NO3)4·5H2O and dissolve it in 5mL methanol. Stir the solution magnetically at 80℃ until all the methanol is evaporated, then add 0.4039g Cu(NO3)2·3H2O and 5mL ultrapure water. After fully dissolved, add 1g SiO2 with particle sizes of 30, 50, 100, and 300nm respectively. Let it stand overnight at room temperature, dry it in an oven at 80℃ for 8h, take it out and grind it through a sieve, and finally put it in a muffle furnace and calcine it at 350℃ for 5h at a heating rate of 10℃ / min to obtain 40wt%-ZC(2) / SiO2-350 catalyst, which is stored in a desiccator for later use.

[0080] Method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural:

[0081] 0.2 g of 5-hydroxymethylfurfural and 19.8 g of isopropanol solvent were added to a 50 mL autoclave, and then 0.2 g of a catalyst (40 wt% -ZC (2) / SiO2-350) was added, the mass ratio of ZrO2, CuO, and carrier was 0.27:0.13:1), the air in the autoclave was replaced with nitrogen three times, the autoclave was closed, stirred at 500 rpm, heated to 140° C. and maintained for 5 h, the reaction was terminated and cooled to room temperature, the reaction mixture was separated, the supernatant was taken, and standard solutions of 5-hydroxymethylfurfural, 2,5-furan dimethanol, etc. were prepared, and quantitative and qualitative analyses were performed using a gas chromatograph. The results are listed in Table 1, No. 31-34.

[0082] Examples 31-34 explored the effect of the particle size of the carrier SiO2 on the catalytic activity. It can be seen that when the calcination temperature is 350°C and the carrier particle size is 15nm, the 5-hydroxymethylfurfural conversion rate is 97.22% and the 2,5-furan dimethanol yield is 90.35% (Example 3). Therefore, the best catalyst carrier is 15nm SiO2.

[0083] Table 1 Test results of Examples 1-32

[0084]

[0085]

[0086]

[0087] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural, characterized in that: The method comprises the following steps: 5-hydroxymethylfurfural, a catalyst and an alcohol solvent are loaded into a reaction kettle, and a closed reaction is carried out under high temperature and inert gas conditions to obtain 2,5-furan dimethanol; the catalyst is a composite catalyst of zirconium oxide and copper oxide supported on silicon oxide.

2. The method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural according to claim 1, characterized in that: The preparation method of the catalyst comprises the following steps: 1) dissolving a zirconium salt and a copper salt in a solvent, adding a silicon oxide carrier and making the silicon oxide carrier dispersed uniformly in the solvent; 2) removing the solvent to obtain a solid, and calcining the solid in high-temperature air to obtain the catalyst.

3. The method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural according to claim 1, characterized in that: The preparation method of the catalyst comprises the following steps: 1) dissolving a zirconium salt in a first solvent and removing the first solvent; 2) then dissolving the zirconium salt and copper salt in a second solvent, and adding a silicon oxide carrier and dispersing it evenly in the second solvent; 3) removing the second solvent to obtain a solid, and calcining the solid in high-temperature air to obtain the catalyst.

4. The method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural according to claim 1, characterized in that: The alcohol solvent is isopropanol; the reaction temperature is 120-170° C.; the reaction time is 3-7 hours; and the silicon oxide carrier is nano silicon oxide.

5. The method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural according to claim 1, characterized in that: The concentration of the 5-hydroxymethylfurfural in the alcohol solvent is 0.1-5wt%; the mass ratio of the catalyst to the 5-hydroxymethylfurfural is (0.5-2):

1.

6. The method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural according to claim 1, characterized in that: The mass ratio of zirconium oxide to copper oxide in the catalyst is 1:2-3:1; the mass ratio of the total mass of zirconium oxide and copper oxide to the mass of the carrier is (0.3-0.5):

1.

7. The method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural according to claim 2 or 3, characterized in that: The zirconium salt is nitrate, and the copper salt is nitrate.

8. The method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural according to claim 2, characterized in that: The solvent can be at least one of methanol, ethanol or water; the method for removing the solvent is heating and drying, and the heating temperature is the boiling point of the solvent - the boiling point + 30°C.

9. The method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural according to claim 3, characterized in that: The first solvent can be at least one of methanol and ethanol, and the second solvent is water; the method for removing the first solvent is heating and drying, and the heating temperature is the boiling point of the first solvent - the boiling point + 30°C; the method for removing the second solvent is heating and drying, and the heating temperature is the boiling point of the second solvent - the boiling point + 30°C.

10. The method for preparing 2,5-furan dimethanol by catalytic conversion of 5-hydroxymethylfurfural according to claim 2 or 3, characterized in that: The calcination temperature is 300-600° C., and the calcination time is 3-10 hours.

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