A method for preparing 2,5-furan dimethanol by catalytic hydrogenation of 5-hydroxymethylfurfural

Abstract

The invention discloses a method for preparing 2,5-furan dimethanol by catalytic hydrogenation of 5-hydroxymethylfurfural, and belongs to the field of fine chemical technology. The method is prepared by reducing a bimetallic aqueous solution with sodium borohydride to obtain a bimetallic catalyst, and then 5-hydroxymethylfurfural, a bimetallic catalyst and isopropanol are added to a reactor, and at a stirring rate of 500rpm, a closed reaction 1-5h is carried out at 100-140 DEG C to obtain a reaction product 2,5-furan dimethanol, 5-hydroxymethylfurfural conversion rate is up to 99.4%, and 2,5-furan dimethanol yield is up to 97.2%. The catalyst preparation method is extremely simple, low in price, and the catalytic system is green and efficient, with broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemicals, and particularly relates to a method for preparing 2,5-furan dimethanol through catalytic hydrogenation of 5-hydroxymethylfurfural. Background Art

[0002] Biomass is widely distributed and abundant in nature. It is an environmentally friendly, clean, and renewable resource with significant practical significance for alleviating fossil fuel shortages and environmental pollution. In recent years, the conversion of biomass resources into platform chemicals has attracted widespread attention. Among these platform compounds, 5-hydroxymethylfurfural (HMF) is considered one of the most important biomass-based platform molecules, widely used in the preparation of multifunctional compounds such as fine chemicals, key pharmaceutical intermediates, functional polyesters, solvents, and liquid fuels. A variety of high-value-added chemicals, such as 2,5-furan dimethanol (BHMF) and 2,5-dimethylfuran (DMF), can be synthesized through chemical reactions such as oxidation and hydrogenation. Among these compounds, 2,5-furan dimethanol, as a widely used chemical intermediate and fuel precursor, offers unique advantages in improving the properties of traditional polyesters and synthesizing green, biodegradable, bio-based polyester materials. It also has significant market potential in the production of resins, polymers, man-made fibers, and crown ethers. However, only a few studies have focused on the selective hydrogenation of HMF to prepare BHMF, primarily because HMF is easily overhydrogenated to DMF and 2,5-dimethyltetrahydrofuran (DMTHF) in the presence of noble metals and hydrogen. Therefore, it is crucial to develop a green, economical, and efficient non-noble metal catalyst to preferentially hydrogenate the aldehyde groups on the HMF molecule while minimizing the hydrogenation of the hydroxymethyl groups at other carbon positions and the C=C hydrogenation of the furan ring. Summary of the Invention

[0003] The purpose 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 hydrogenation of 5-hydroxymethylfurfural.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A method for preparing 2,5-furan dimethanol by catalytic hydrogenation of 5-hydroxymethylfurfural comprises adding 5-hydroxymethylfurfural, a ZrCu bimetallic catalyst and isopropyl alcohol into a closed reactor, reacting at 100-140° C. for 1-5 hours at a stirring rate of 500 rpm, and then cooling to room temperature to obtain the 2,5-furan dimethanol.

[0006] The preparation method of the above-mentioned ZrCu bimetallic catalyst comprises the following steps:

[0007] (1) Dissolve the bimetallic salt in deionized water, which is called solution A. Dissolve sodium borohydride in deionized water, which is called solution B.

[0008] (2) Use a dropper to slowly add solution B into solution A. After all the solution has been added and the bubbles have been released, stir manually until a uniformly mixed colloid is obtained.

[0009] (3) The colloid is aged, dried, ground and sieved to obtain the ZrCu bimetallic catalyst.

[0010] Furthermore, the mass ratio of the above-mentioned isopropanol, 5-hydroxymethylfurfural and ZrCu bimetallic catalyst is 99:1:(0.25-1.5).

[0011] Furthermore, the concentration of the sodium borohydride is 5 mol / L.

[0012] Furthermore, the mass ratio of the zirconium oxychloride, copper nitrate and sodium borohydride is 2.4:1.8:0.38-1.14.

[0013] Furthermore, the aging time is 1 hour, and the drying temperature is 80°C.

[0014] The beneficial effects of the present invention are:

[0015] (1) The present invention can adjust the active sites and acid-base strength of the catalyst by adjusting the amount of NaBH4 added; and can prepare 2,5-furan dimethanol with a higher yield by adjusting the reaction conditions.

[0016] (2) In the bimetallic catalyst prepared by the present invention, the strong synergistic effect between the two metals Cu and Zr plays an important role in the reaction pathway of catalytic hydrogenation of 5-hydroxymethylfurfural to produce 2,5-furan dimethanol.

[0017] (3) The non-precious metal catalyst prepared by the present invention has low cost, simple preparation method, mild reaction conditions, high economy and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 : XRD patterns of the catalysts prepared in Examples 2-6, Example 8 and Example 10.

[0019] Figure 2 : SEM images of the catalysts prepared in Example 2 and Example 4. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0021] The preparation method of the catalyst in the following embodiment includes:

[0022] A certain amount of metal precursor was weighed and dissolved in 10 mL of deionized water under ultrasonic assistance, which was recorded as solution A. Another certain amount of sodium borohydride was dissolved in deionized water under ultrasonic assistance to a concentration of 5 mol / L, which was recorded as solution B. After the ultrasound is completed, solution B was slowly added to solution A with a dropper. After all the drops were added and the bubbles were released, it was manually stirred until a uniformly mixed colloid was obtained. After that, it was placed in an oven after aging and dried at 80°C overnight. The dried product was then ground in a mortar and passed through an 80-120 mesh sieve to obtain the bimetallic catalyst, which was named ZrCuO x -y, where "y" represents the amount of sodium borohydride solution added.

[0023] Example 1 ZrCuO x -0

[0024] 2.4 g ZrOCl2·8H2O and 1.8 g Cu(NO3)2·3H2O were accurately weighed and dissolved in 10 mL deionized water under ultrasound assistance, which was recorded as solution A. After standing for 1 hour, the aged product was placed in an oven and dried at 80°C overnight. The dried product was then ground in a mortar and passed through an 80-120 mesh sieve to obtain the bimetallic catalyst ZrCuO x -0.

[0025] Example 2 ZrCuO x -2

[0026] Accurately weigh 2.4g ZrOCl2·8H2O and 1.8g Cu(NO3)2·3H2O, dissolve them in 10 mL deionized water under ultrasonic assistance, and record them as solution A. Accurately weigh 0.38g NaBH4, dissolve them in 2 mL deionized water under ultrasonic assistance, and record them as solution B. After the ultrasound is completed, use a dropper to slowly add solution B to solution A. After all the drops are added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, let it stand for 1 hour, put the aged product into an oven, and dry it at 80°C overnight. Then, grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named ZrCuO x -2.

[0027] Example 3 ZrCuO x -3

[0028] Accurately weigh 2.4g ZrOCl2·8H2O and 1.8g Cu(NO3)2·3H2O, dissolve them in 10 mL deionized water under ultrasonic assistance, and record them as solution A. Accurately weigh 0.57g NaBH4, dissolve them in 3 mL deionized water under ultrasonic assistance, and record them as solution B. After the ultrasound is completed, solution B is slowly added dropwise to solution A with a dropper. After all the drops are added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, place it for 1 hour, put the aged product into an oven, and dry it at 80°C overnight. Then, grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named ZrCuO x -3.

[0029] Example 4 ZrCuO x -4

[0030] Accurately weigh 2.4g ZrOCl2·8H2O and 1.8g Cu(NO3)2·3H2O, dissolve them in 10 mL deionized water under ultrasonic assistance, and record them as solution A. Accurately weigh 0.76g NaBH4, dissolve them in 4 mL deionized water under ultrasonic assistance, and record them as solution B. After the ultrasound is completed, solution B is slowly added dropwise to solution A with a dropper. After all the drops are added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, let it stand for 1 hour, put the aged product into an oven, and dry it at 80°C overnight. Then, grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named ZrCuO x -4.

[0031] Example 5 ZrCuO x -5

[0032] Accurately weigh 2.4g ZrOCl2·8H2O and 1.8g Cu(NO3)2·3H2O, dissolve them in 10 mL deionized water under ultrasonic assistance, and record them as solution A. Accurately weigh 0.95g NaBH4, dissolve them in 5 mL deionized water under ultrasonic assistance, and record them as solution B. After the ultrasound is completed, use a dropper to slowly add solution B to solution A. After all the drops are added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, let it stand for 1 hour, put the aged product into an oven, and dry it at 80°C overnight. Then, grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named ZrCuO x -5.

[0033] Example 6 ZrCuO x -6

[0034] Accurately weigh 2.4g ZrOCl2·8H2O and 1.8g Cu(NO3)2·3H2O, dissolve them in 10 mL deionized water under ultrasonic assistance, and record them as solution A. Accurately weigh 1.14g NaBH4, dissolve them in 6 mL deionized water under ultrasonic assistance, and record them as solution B. After the ultrasonic treatment, slowly add solution B to solution A with a dropper. After all the solution is added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, place it in an oven for 1 hour, and dry it at 80°C overnight. Then, grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named ZrCuO x -6.

[0035] The XRD patterns of the bimetallic catalysts prepared in Examples 2-6 are as follows: Figure 1 As shown, the bimetallic catalyst ZrCuO was reduced by regulating sodium borohydride. x -y diffraction peaks at 31.5°, 44.4°, 49.7° and 56.6° correspond to the (102), (103), (013) and (302) crystal planes of ZrO2 (PDF#97-017-3963), respectively, indicating that these catalysts exhibit diffraction peaks similar to those of single metal ZrOx-4 and all belong to the orthorhombic system. After the introduction of Cu species, new diffraction peaks appeared in the XRD pattern. The diffraction peaks at 17.6°, 28.9° and 31.8° correspond to the (100), (-111) and (111) crystal planes of ZrO2 (PDF#97-024-8445), respectively. The diffraction peaks at 38.8° and 38.9° correspond to the (111) and (200) crystal planes of CuO (PDF#97-029-1387), respectively, both of which belong to the monoclinic system. This indicates that the introduction of Cu species changes the crystal form selection of ZrO2, and different addition amounts of sodium borohydride solution have a significant effect on the formation of catalyst species and crystal forms. With the increase in the amount of sodium borohydride solution, the monoclinic ZrO2 will gradually transform into the orthorhombic system. The ratio of orthorhombic and monoclinic systems in the XRD pattern increases, the preferred orientation of the crystal form changes, and the diffraction peak of CuO gradually weakens, indicating that it is gradually reduced to dispersed Cu2O and Cu. From the XRD pattern of the best catalyst CuZrOx-4, it can be seen that the two strongest diffraction peaks belong to the orthorhombic and monoclinic systems of ZrO2, respectively, and their ratio is close to 1. At the same time, the (111) and (200) crystal planes of CuO are present, which verifies the successful synthesis of the Zr-Cu bimetallic catalyst.

[0036] After adding 0.2g of 5-hydroxymethylfurfural, 0.2g of bimetallic catalyst and 19.8g of isopropanol to a stainless steel autoclave, the reactor was sealed. After high-purity nitrogen was introduced to replace the air in the reactor 3-4 times, the reaction mixture was stirred at a speed of 500rpm in a closed reactor, heated to 120°C and maintained for 2h, and the reaction was terminated and naturally cooled to room temperature. After the experiment, the reaction mixture was centrifuged, the supernatant was taken, and standard solutions such as 5-hydroxymethylfurfural and 2,5-furan dimethanol were prepared. Gas chromatograph was used for quantitative analysis, and gas chromatography-mass spectrometry was used for qualitative analysis. The test results of Examples 1-6 are listed in Table 1.

[0037] The effect of sodium borohydride dosage on catalyst activity was investigated. Table 1 shows that, under the conditions of 120°C, 2 h, and 500 rpm, when no sodium borohydride solution was added, the reaction products dispersed, and the yield of 2,5-furandimethanol was extremely low. With increasing sodium borohydride dosage, the conversion of 5-hydroxymethylfurfural and the selectivity for 2,5-furandimethanol both initially increased and then decreased. The best effect was achieved when 4 mL of sodium borohydride solution was used, with a 5-hydroxymethylfurfural conversion of 99.4% and a 2,5-furandimethanol yield of 97.2%. When 2 mL of sodium borohydride solution was used, both the 5-hydroxymethylfurfural conversion and 2,5-furandimethanol yield were lower, but the selectivity reached 88.3%. This may be due to insufficient sodium borohydride dosage, insufficient ZrO2 formation during catalyst preparation, and insufficient Cu reduction, resulting in insufficient catalyst activity. However, when the sodium borohydride solution dosage was increased to 6 mL, both the conversion rate and yield dropped significantly. This is likely due to the reduction of CuO to Cu2O and Cu under the conditions of excessive sodium borohydride. The active sites of the catalyst are primarily ZrO2 and CuO. Adjusting the sodium borohydride dosage controls the content and interaction of ZrO2 and CuO in the catalyst, thereby adjusting the active sites of the catalyst. This indicates that the sodium borohydride dosage has a significant impact on the catalyst activity. Therefore, the optimal sodium borohydride solution dosage is 4 mL.

[0038] Table 1 Catalytic results of Examples 1-6

[0039]

[0040] Example 7 ZrCuO x -4

[0041] Accurately weigh 2.4g ZrOCl2·8H2O and 1.8g Cu(NO3)2·3H2O, dissolve them in 10 mL deionized water under ultrasonic assistance, and record it as solution A. Accurately weigh 0.76g NaBH4, dissolve them in 4mL deionized water under ultrasonic assistance, and record it as solution B. After the ultrasonic treatment, slowly add solution B to solution A with a dropper. After all the solution is added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, let it stand for 1 hour, put the aged product into an oven, and dry it at 80°C overnight. Then, grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named ZrCuO x -4.

[0042] Example 8 ZrO x -4

[0043] 2.4 g of ZrOCl2·8H2O was accurately weighed and dissolved in 10 mL of deionized water under ultrasonic assistance, which was recorded as solution A. 0.76 g of NaBH4 was also accurately weighed and dissolved in 4 mL of deionized water under ultrasonic assistance, which was recorded as solution B. After the ultrasonic treatment, solution B was slowly added dropwise to solution A with a dropper. After all the solution was added and the bubbles were released, it was manually stirred until a uniformly mixed colloid was obtained. After that, it was left for 1 hour. The aged product was placed in an oven and dried at 80°C overnight. The dried product was then ground in a mortar and passed through an 80-120 mesh sieve to obtain the bimetallic catalyst, which was named ZrO x -4.

[0044] Example 9 ZrO x -2

[0045] Accurately weigh 2.4 g of ZrOCl2·8H2O and dissolve it in 10 mL of deionized water under ultrasonic assistance, which is recorded as solution A. Accurately weigh 0.38 g of NaBH4 and dissolve it in 2 mL of deionized water under ultrasonic assistance, which is recorded as solution B. After the ultrasonic treatment, slowly add solution B to solution A with a dropper. After all the solution is added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, let it stand for 1 hour, put the aged product into an oven, and dry it at 80°C overnight. Then, grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named ZrO x -2.

[0046] Example 10 CuO x -4

[0047] Accurately weigh 1.8g of Cu(NO3)2·3H2O and dissolve it in 10 mL of deionized water under ultrasonic assistance, which is recorded as solution A. Accurately weigh 0.76g of NaBH4 and dissolve it in 4 mL of deionized water under ultrasonic assistance, which is recorded as solution B. After the ultrasonic treatment, slowly add solution B to solution A with a dropper. After all the solution is added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, place it in an oven for 1 hour, put the aged product in a oven, and dry it at 80°C overnight. Then, grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named CuO x -4.

[0048] Example 11 CuO x -2

[0049] Accurately weigh 1.8g of Cu(NO3)2·3H2O and dissolve it in 10 mL of deionized water under ultrasonic assistance, which is recorded as solution A. Accurately weigh 0.38g of NaBH4 and dissolve it in 2 mL of deionized water under ultrasonic assistance, which is recorded as solution B. After the ultrasonic treatment, slowly add solution B to solution A with a dropper. After all the solution is added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, place it in an oven for 1 hour, put the aged product in a oven, and dry it at 80°C overnight. Then, grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named CuO x -2.

[0050] Example 12 ZrNiO x -4

[0051] Accurately weigh 2.4g ZrOCl2·8H2O and 1.8g Ni(NO3)2·6H2O, dissolve them in 10 mL deionized water under ultrasonic assistance, and record it as solution A. Accurately weigh 0.76g NaBH4, dissolve them in 4mL deionized water under ultrasonic assistance, and record it as solution B. After the ultrasound is completed, use a dropper to slowly add solution B to solution A. After all the drops are added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, place it for 1 hour, put the aged medicine into an oven, and dry it at 80°C overnight. Then grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named ZrNiO x -4.

[0052] Example 13 ZrCoO x -4

[0053] Accurately weigh 2.4g ZrOCl2·8H2O and 1.8g Co(NO3)2·6H2O, dissolve them in 10 mL deionized water under ultrasonic assistance, and record it as solution A. Accurately weigh 0.76g NaBH4, dissolve them in 4mL deionized water under ultrasonic assistance, and record it as solution B. After the ultrasound is completed, use a dropper to slowly add solution B to solution A. After all the drops are added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. After that, let it stand for 1 hour, put the aged medicine into an oven, and dry it at 80°C overnight. Then grind the dried product in a mortar and pass it through an 80-120 mesh sieve to obtain the bimetallic catalyst, which is named ZrCoO x -4.

[0054] The XRD patterns of catalysts 8 and 10 are shown in Figure 2. Figure 1 As shown, the diffraction peaks of the monometallic catalyst ZrOx-4 at 31.5°, 44.4°, 49.7°, and 56.6° correspond to the (102), (103), (013), and (302) crystal planes of ZrO2 (PDF#97-017-3963), respectively, indicating that the main component of the catalyst is ZrO2, which belongs to the orthorhombic system. The diffraction peaks of the monometallic catalyst CuOx-4 at 36.5°, 43.3°, and 50.4° correspond to the 111 crystal plane of Cu2O (PDF#97-002-6963) and the (111) and (200) crystal planes of Cu (PDF#97-004-3493), respectively, indicating that the main components of the catalyst are Cu2O and Cu, both of which belong to the monoclinic system. This characterization result shows that when the amount of sodium borohydride solution added is 4mL, a large amount of monoclinic ZrO2 can be effectively synthesized in the catalyst prepared by single metal Zr, while single metal Cu will be further reduced due to excessive sodium borohydride, and more crystal characteristics of Cu2O and Cu will be shown in the XRD spectrum. Therefore, controlling the amount of sodium borohydride solution added has an important influence on the catalytic activity of the catalyst.

[0055] A stainless steel autoclave was charged with 0.2 g of 5-hydroxymethylfurfural, 0.2 g of a bimetallic catalyst, and 19.8 g of isopropyl alcohol, and the reactor was sealed. High-purity nitrogen was introduced three to four times to displace the air in the reactor. The mixture was then stirred at 500 rpm and heated to 120°C for 2 hours. The reaction was terminated and allowed to cool naturally to room temperature. Following the experiment, the reaction mixture was centrifuged, and the supernatant was collected to prepare standard solutions of 5-hydroxymethylfurfural and 2,5-furan dimethanol. Quantitative analysis was performed using gas chromatography, and qualitative analysis was performed using gas chromatography-mass spectrometry. The results are listed in Table 2.

[0056] The effect of metal components on catalytic activity was investigated. As shown in Table 2, under the conditions of 120 °C, 2 h and 500 rpm, when only single metal Zr or Cu was used to prepare the catalyst, both showed lower 5-hydroxymethylfurfural conversion rate and 2,5-furan dimethanol yield. In addition, the amount of sodium borohydride was also very important. When the amount of sodium borohydride solution was 2 mL, ZrO x -2 is basically ineffective, while CuO x -2 has a lower effect. When the amount of sodium borohydride solution is 4mL, the effects of the two are just the opposite, which can be clearly seen from the SEM ( Figure 2 ), this may be that the excess sodium borohydride is sufficient to form flaky zirconium oxide, but CuO is over-reduced to Cu2O and Cu, causing a large amount of Cu species to aggregate and lose activity. When a bimetallic catalyst prepared using Zr and Cu showed a higher yield than a single metal and its physical mixture, up to 97.2%, which also shows that there is a good synergistic effect between the Cu-Zr two metals. Usually in the process of HMF hydrogenation to BHMF, Cu-based catalysts usually require higher temperatures than Ni-based and Co-based catalysts. Therefore, the corresponding ZrNiO x -4 and ZrCoO x- 4. Comparative experiments show that under the same conditions, both catalysts exhibit a certain transfer hydrogenation effect, but neither is as good as ZrCuO x The effect of -4 further proves that the two metals have a strong synergistic effect at lower temperatures. Therefore, Zr-Cu bimetallic catalysts have obvious advantages over single metal catalysts.

[0057] Table 2 Catalytic results of Examples 7-13

[0058]

[0059] Example 14

[0060] Add 0.2g 5-hydroxymethylfurfural, 0.2g ZrCuO x The reaction vessel was sealed after adding 4-4 ​​catalyst and 19.8g of isopropanol. After replacing the air in the reactor with high-purity nitrogen three to four times, the air was stirred in the sealed reactor at 500 rpm and heated to 100, 110, 120, 130, and 140°C for 2 hours. The reaction was terminated and naturally cooled to room temperature. After the experiment, the reaction mixture was centrifuged and the supernatant was collected. Standard solutions of 5-hydroxymethylfurfural and 2,5-furan dimethanol were prepared. Quantitative analysis was performed using gas chromatography and qualitative analysis was performed using gas chromatography-mass spectrometry. The test results are listed in Table 3.

[0061] The effect of reaction temperature on catalytic activity was investigated. Table 3 shows that at 100°C, 2 h, and 500 rpm, the 5-HMF conversion was 83.6%, and the 2,5-furandimethanol yield was 82.4%. At 140°C, 2 h, and 500 rpm, the 5-HMF conversion was 99.9%, and the 2,5-furandimethanol yield was 76.8%. At 120°C, 2 h, and 500 rpm, the 5-HMF conversion was 99.4%, and the 2,5-furandimethanol yield increased to 97.2%. This indicates that high temperatures facilitate the conversion of 5-HMF, but excessively high temperatures lead to the production of more byproducts and reduced 2,5-furandimethanol selectivity. Therefore, an appropriate reaction temperature can yield higher yields of 2,5-furandimethanol, with the optimal temperature being 120°C.

[0062] Table 3 Effect of reaction temperature on catalytic activity

[0063]

[0064] Example 15

[0065] Add 0.2g 5-hydroxymethylfurfural, 0.2g ZrCuO x The reaction vessel was sealed after adding 4-4 ​​catalyst and 19.8g of isopropanol. After replacing the air in the reactor with high-purity nitrogen gas 3-4 times, the reaction vessel was stirred at 500 rpm and heated to 120°C for 1, 2, 3, 4, and 5 hours, respectively. The reaction was terminated and naturally cooled to room temperature. After the experiment, the reaction mixture was centrifuged and the supernatant was collected. Standard solutions of 5-hydroxymethylfurfural and 2,5-furan dimethanol were prepared. Quantitative analysis was performed using gas chromatography and qualitative analysis was performed using gas chromatography-mass spectrometry. The test results are listed in Table 4.

[0066] The effect of reaction time on catalytic activity was investigated. Table 4 shows that under the conditions of 120°C, 1 hour, and 500 rpm, the 5-HMF conversion was 93.6%, and the 2,5-furandimethanol yield was 86.4%. However, under the conditions of 120°C, 2 hours, and 500 rpm, the 5-HMF conversion was 99.4%, and the 2,5-furandimethanol yield increased to 97.2%. When the reaction time was increased to 5 hours, the conversion remained almost unchanged, but the yield gradually decreased. This may be due to the occurrence of other side reactions with the prolonged reaction time, which reduced the 2,5-furandimethanol yield. Therefore, the optimal reaction time is 2 hours.

[0067] Table 4 Effect of reaction time on catalytic activity

[0068]

[0069] Example 16

[0070] 0.2 g 5-hydroxymethylfurfural, 19.8 g isopropanol and 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 g ZrCuO were added to a stainless steel autoclave. x After adding a -4 catalyst, the reactor was sealed. High-purity nitrogen was introduced to displace the air in the reactor 3-4 times. The reaction mixture was stirred at 500 rpm and heated to 120°C for 2 hours each time. The reaction was terminated and naturally cooled to room temperature. After the experiment, the reaction mixture was centrifuged and the supernatant was collected. Standard solutions of 5-hydroxymethylfurfural and 2,5-furan dimethanol were prepared. Quantitative analysis was performed using gas chromatography and qualitative analysis was performed using gas chromatography-mass spectrometry. The results are listed in Table 5.

[0071] The effect of catalyst dosage on catalytic activity was investigated. Table 5 shows that at 120°C, 2 h, and 500 rpm, a catalyst dosage of 0.05 g resulted in a 73.6% conversion of 5-hydroxymethylfurfural and a 66.4% yield of 2,5-furandimethanol. At 0.2 g, the conversion of 5-hydroxymethylfurfural increased to 99.4% and the yield of 2,5-furandimethanol to 97.2%. When the catalyst dosage was increased to 0.3 g, the conversion remained almost unchanged, but the yield gradually decreased. This is likely due to the fact that excessive catalyst dosage provides more catalytic active sites, resulting in a continuous increase in byproducts in the reaction system and a decrease in the yield of 2,5-furandimethanol. Therefore, the optimal catalyst dosage is 0.2 g.

[0072] Table 5 Effect of catalyst dosage on catalytic activity

[0073]

[0074] As shown in Tables 1-5, a higher yield of 2,5-furan dimethanol (97.2%) can be obtained by adjusting the metal composition, the amount of sodium borohydride solution, the reaction temperature, the reaction time and the amount of catalyst.

[0075] The above description is merely a preferred embodiment of the present invention and therefore cannot be used to limit the scope of the present invention. In other words, equivalent changes and modifications made according to the scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A method for preparing 2,5-furan dimethanol by catalytic hydrogenation of 5-hydroxymethylfurfural, characterized in that: 5-Hydroxymethylfurfural, a ZrCu bimetallic catalyst, and isopropanol are added to a closed reactor, reacted at 100-140° C. for 1-5 hours at a stirring rate of 500 rpm, and then cooled to room temperature to obtain the 2,5-furan dimethanol; The preparation method of the ZrCu bimetallic catalyst comprises the following steps: (1) Dissolve the bimetallic salt in deionized water, which is referred to as solution A. Separately, dissolve sodium borohydride in deionized water, which is referred to as solution B. (2) Slowly add solution B to solution A using a dropper. After all solution B is added and the bubbles are released, stir manually until a uniformly mixed colloid is obtained. (3) The colloid is aged, dried, ground and sieved to obtain the ZrCu bimetallic catalyst; The double metal salts in step (1) are zirconium oxychloride and copper nitrate.

2. The method according to claim 1, wherein: The mass ratio of the isopropanol, 5-hydroxymethylfurfural and ZrCu bimetallic catalyst is 99:1:(0.25-1.5).

3. The method according to claim 1, wherein: The concentration of sodium borohydride in step (1) is 5 mol / L.

4. The method according to claim 1, wherein: The mass ratio of zirconium oxychloride, copper nitrate and sodium borohydride is 2.4:1.8:0.38-1.

14.

5. The method according to claim 1, wherein: The aging time in step (3) is 1 hour, and the drying temperature is 80°C.

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