A zirconium phosphate-supported H-Beta-25 molecular sieve catalyst for the one-pot synthesis of γ-valerol from furfural.

Abstract

This invention discloses a method for the efficient one-pot synthesis of γ-valerol from furfural. The method involves a simple precipitation or hydrothermal process, followed by rotary evaporation and calcination to obtain a zirconium phosphate-supported H-beta(25) molecular sieve catalyst. The catalytic activity can be improved by adjusting the ratio of zirconium and phosphorus precursors, as well as the mass ratio of zirconium phosphate to zeolite molecular sieve. This zirconium phosphate-supported H-beta(25) molecular sieve exhibits highly efficient catalytic transfer hydrogenation, etherification, and alcoholysis activities, enabling the efficient one-pot synthesis of γ-valerol from furfural in isopropanol.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fine chemical industry, and particularly relates to a method for efficiently synthesizing gamma-valerolactone through one-pot furoyl. BACKGROUND

[0002] With the continuous growth of population, the development and application of fossil fuels are also increasing, and the shortage of fuels and environmental pollution caused by it are increasingly apparent. Therefore, it has become a development trend to produce fuels and chemicals from cheap, abundant and sustainable biomass to replace traditional fossil fuels. Several biofuels have been identified, including bioethanol, biodiesel, gamma-valerolactone (GVL) and the like.

[0003] Gamma-valerolactone (GVL) is a high-value chemical with a wide range of applications. It can be used as a fuel additive, a chemical solvent, and an intermediate for producing olefins, polymers and chemicals. In addition, gamma-valerolactone can also be used as a precursor for producing various liquid hydrocarbon fuels suitable for gasoline, diesel and aviation kerosene. Catalytic conversion of furfural to prepare gamma-valerolactone is considered to be a very promising synthesis route for gamma-valerolactone. Currently, the hydrogenation reactions involved in the preparation of gamma-valerolactone from furfural mainly include direct hydrogenation and transfer hydrogenation. The former is usually carried out in the presence of hydrogen gas (> 30 bar) on a series of noble metal catalysts (such as Ru, Au, Pd), but is easily limited by factors such as high cost of catalyst, excessive hydrogenation of substrate, and high-pressure hydrogen gas. Transfer hydrogenation usually uses formic acid or alcohol as a hydrogen donor, and is more attractive and safe because it does not require the use of high-pressure hydrogen gas. Although noble metal catalysts (such as Au, Pt, Pd and Ru) have good catalytic activity in transfer hydrogenation, the high cost of these metals limits their industrial application. Therefore, it is necessary and urgent to explore more efficient, economical and sustainable catalysts.

[0004] The conversion of furfural to gamma-valerolactone in isopropanol involves multiple steps such as hydrogenation, alcoholysis or etherification, and the reaction process requires the synergistic effect of Lewis acid and Bronsted acid. Specifically, under the catalysis of Lewis acid, furfural (FF) is reduced to furfuryl alcohol (FFA) by MPV transfer hydrogenation with isopropanol as the hydrogen source; FFA is etherified with the solvent alcohol to form furfuryl ether (FE) under the action of Lewis acid or Bronsted acid; FE is subjected to ring-opening alcoholysis to form isopropyl levulinate (IPL) under the catalysis of Bronsted acid; IPL is further reduced to isopropyl 4-hydroxyvalerate (IPHV) by transfer hydrogenation under the action of Lewis acid with isopropanol as the hydrogen source; IPHV is easily cyclized to form the more stable gamma-valerolactone (GVL) by losing one molecule of isopropanol. Since FF and FFA are prone to undergo side reactions such as condensation under the action of Bronsted acid to form humus, the selectivity of the target reaction product is low; at the same time, the catalysis of acetoacetic acid ester transfer hydrogenation to synthesize GVL requires a strong Lewis acid, so the catalyst needs to have a strong Lewis acid site and a proper Bronsted acid site to catalyze the efficient conversion of FF to GVL. However, it is a technical difficulty to be solved to design and synthesize a multifunctional acid catalyst with specific Lewis acid sites and Bronsted acid sites for the efficient conversion of furfural to gamma-valerolactone.

[0005] Recently, zirconium-based catalysts have been widely used in one-pot catalytic conversion of FF to prepare GVL with isopropanol as the solvent and hydrogen donor. However, as mentioned above, the one-pot hydrogenation of FF to prepare gamma-valerolactone with isopropanol as the solvent involves multiple steps, each step has different requirements for reaction conditions and catalytic active sites, the overall path is long, and the yield of gamma-valerolactone is generally low. Therefore, it is extremely important to design a green, cheap and efficient multifunctional catalyst for the one-pot preparation of gamma-valerolactone from furfural. SUMMARY

[0006] The present application aims to overcome the shortcomings of the prior art and provides a method for efficiently synthesizing gamma-valerolactone from furfural by one-pot method. The present application provides a simple and easy-to-scale method for preparing a zirconium phosphate supported H-beta(25) molecular sieve catalyst. In this method, the desired catalyst can be obtained by simple precipitation combined with rotary evaporation loading and calcination, and by adjusting the ratio of zirconium element precursor and phosphorus element precursor, the content of Lewis acid and Bronsted acid can be adjusted, thereby improving the catalytic activity of the catalyst and promoting the catalyst to efficiently catalyze the one-pot synthesis of gamma-valerolactone from furfural in isopropanol.

[0007] To achieve the above-mentioned purposes, the technical solutions of the present application are as follows:

[0008] One of the technical solutions adopted by the present application to solve its technical problems is: a preparation method of a zirconium phosphate loaded H-beta(25) molecular sieve catalyst, comprising the following steps: dissolving ZrOCl2*8H2O in deionized water under magnetic stirring, and dissolving NH4H2PO4 in deionized water. Under vigorous stirring, slowly drop the prepared NH4H2PO4 aqueous solution into the ZrOCl2*8H2O aqueous solution, then add H-beta(25) powder into the above mixed solution, and stir vigorously at room temperature for 3-6 h, the obtained suspension is separated by rotary evaporation at 60°C to obtain a solid catalyst, the recovered catalyst is dried at 105°C overnight, after grinding, it is calcined in a muffle furnace under air at a heating rate of 5°C / min, at 380-420°C for 3-5 h to obtain the zirconium phosphate loaded H-beta(25) molecular sieve catalyst, denoted as ZPBX(xyz) composite catalyst, wherein X represents the molar ratio of zirconium to phosphorus, i.e. Zr / P molar ratio, x / z represents the mass ratio of zirconium precursor to H-beta(25), and x / y=X also represents the molar ratio of zirconium to phosphorus, i.e. Zr / P molar ratio.

[0009] Further, the molar ratio of Zr to P is 0.5-2:1, and the mass ratio of ZrOCl2*8H2O to H-beta(25) is 0.5-8:1. Under the above conditions, X=0.5-2, x / z=0.5-8. Among them, the addition amount of H-beta(25) molecular sieve refers to the mass of H-beta(25) molecular sieve added when the addition amount of ZrOCl2*8H2O is 1.4-2.8 g. Preferably, the molar ratio of Zr to P is 1:1, and the mass ratio of ZrOCl2*8H2O to H-beta(25) is 1.4:0.35. Under this condition, the catalytic activity of the zirconium phosphate loaded H-beta(25) molecular sieve catalyst is better. Further, the addition amount of NH4H2PO4 is kept at 0.5 g, and the addition amount of ZrOCl2*8H2O is 0.7-2.8 g. Further, the concentration of NH4H2PO4 aqueous solution is 0.8-1.2 mol / L, and the addition amount of ZrOCl2*8H2O is 1.4 g.

[0010] The second technical solution adopted by the present application to solve its technical problems is: a zirconium phosphate loaded H-beta(25) molecular sieve catalyst prepared according to the hydrothermal synthesis preparation method described above. Among them, X represents the molar ratio of Zr to P, X=1, the addition amount of H-beta(25) molecular sieve represents the mass of H-beta(25) molecular sieve added when the addition amount of ZrOCl2*8H2O, x / z=4.

[0011] The third technical solution of the present application for solving the technical problem is: application of the above-mentioned zirconium phosphate loaded H-beta(25) molecular sieve catalyst in preparation of gamma-valerolactone.

[0012] The fourth technical solution of the present application for solving the technical problem is: a method for preparing gamma-valerolactone by using the above-mentioned zirconium phosphate loaded H-beta(25) molecular sieve catalyst, wherein furfural and isopropyl alcohol are mixed, and then the zirconium phosphate loaded H-beta(25) molecular sieve catalyst is added, and the reaction is carried out under a closed condition, the reaction temperature is 140-220°C, and the reaction time is 2-10 h.

[0013] Further, the specific application method comprises: adding furfural, the zirconium phosphate loaded H-beta(25) molecular sieve catalyst and isopropyl alcohol into a reaction kettle, introducing N2 to exchange air to completely discharge air in the kettle, then charging 5 bar N2 into the kettle, stirring the reaction kettle at a rotating speed of 800 rpm after sealing, heating to 140-220°C and keeping for 2-10 h, and after the reaction is completed, quickly cooling the reaction kettle to prepare gamma-valerolactone.

[0014] The present application has the following advantages:

[0015] The present application provides a simple and easy to scale method for preparing a zirconium phosphate loaded H-beta(25) molecular sieve catalyst. The required catalyst can be obtained by a simple precipitation method combined with rotary evaporation loading and calcination, and by adjusting the ratio of zirconium element precursors and phosphorus element precursors, the content of Lewis acid and Bronsted acid can be adjusted, and the catalytic activity of the catalyst is improved, and the catalyst can realize efficient catalysis of furfural in isopropyl alcohol to synthesize gamma-valerolactone by one-pot method.

[0016] The main feature of the present application is to adjust the ratio of Lewis acid and Bronsted acid in the catalyst by adjusting the ratio of zirconium element precursor and phosphorus element precursor, and the ratio of zirconium phosphate and H-beta(25) molecular sieve mass ratio, and finally realize the target catalytic effect; by using the precipitation method or hydrothermal synthesis, rotary evaporation loading two preparation methods, observing the influence of different preparation methods on the morphology and catalytic performance of the catalyst, and selecting the optimal preparation method for further discussion. The research results show that the catalyst synthesized by the precipitation method and the rotary evaporation loading preparation method has a uniform distribution and the best catalytic performance, while the catalyst synthesized by the hydrothermal synthesis method and the rotary evaporation loading preparation method has a slightly smaller specific surface area, and under the same reaction conditions, the catalytic performance is relatively poor, and the possible reason is that the acidity of the sample prepared by the precipitation method (126.74 μmol / g) is significantly higher than that of the sample prepared by the hydrothermal synthesis method (65.73 μmol / g), and the ratio of Lewis acid and Bronsted acid of the sample prepared by the precipitation method (2.08) is greater than that of the sample prepared by the hydrothermal synthesis method (1.90), and appropriate acidity can improve the selectivity of the catalyst, and excessive Bronsted acid can lead to the generation of other by-products. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 XRD patterns of a series of ZPBX catalysts with different Zr / P ratios were explored.

[0018] Figure 2 XRD patterns of a series of ZPB1.0(xyz) catalysts with different mass ratios of zirconium precursor and H-beta(25) zeolite were explored. DETAILED DESCRIPTION

[0019] The present application is further described in conjunction with the following examples. Unless otherwise specified, the reagents and instruments used in the following examples are commercially available products. The specific implementation examples are as follows:

[0020] Precipitation method for preparing catalyst: accurately weigh 1.4 g of ZrOCl2·8H2O and dissolve in 8.8 mL of deionized water under magnetic stirring, at the same time, dissolve 0.5 g of NH4H2PO4 in 4.4 mL of deionized water. Under vigorous stirring, slowly add the prepared NH4H2PO4 aqueous solution to the ZrOCl2·8H2O aqueous solution, then add 0.35 g of H-beta(25) powder to the above mixed solution, and stir vigorously at room temperature for 6 h. The obtained suspension is separated by rotary evaporation at 60°C to obtain a solid catalyst, and the recovered solid catalyst is dried at 105°C overnight, ground and calcined in a muffle furnace under air at a heating rate of 5°C / min, 400°C for 4 h to obtain the zirconium phosphate loaded H-beta(25) molecular sieve catalyst, which is denoted as ZPB1.0(441).

[0021] Into a 100 mL autoclave, 0.096 g of furfural and 20 mL of isopropyl alcohol were added, followed by 0.192 g of catalyst. The autoclave was purged with nitrogen three times to replace the air in the autoclave and then filled with 5 bar of N2. The autoclave was sealed and stirred at a speed of 800 rpm. The temperature was heated to 140, 160, 180, 200, and 220 °C, respectively, and maintained for 8 h. The reaction was terminated by cooling to room temperature. The reaction mixture was centrifuged, and the supernatant was taken. Standard solutions of furfural, γ-valerolactone, and the like were prepared. Quantitative analysis was performed using a gas chromatograph, and qualitative analysis was performed using a gas chromatograph-mass spectrometer. The results are listed in Table 1, Nos. 1-5.

[0022] The effect of reaction temperature on catalytic activity was investigated. When the reaction was carried out at 140 °C, the substrate was almost completely converted within 8 h, but the GVL yield was only 53.95%. Based on the mass spectrometry results, a high concentration of IPL was detected. When the temperature was increased, the FF conversion rate remained almost unchanged, but the GVL yield gradually increased. When the temperature was increased to 200 °C, the yield reached 63.30% after only 2 h of reaction, and the yield reached a maximum of 82.60% when the time was extended to 8 h. When the temperature was further increased to 220 °C, the yield decreased, and the amount of angelica lactone, which was not timely hydrogenated to form the target product GVL, increased, resulting in a decrease in the GVL yield. In summary, the optimal reaction temperature was 200 °C.

[0023] The corresponding catalysts were prepared according to the methods of Examples 1-5.

[0024] Into a 100 mL autoclave, 0.096 g of furfural and 20 mL of isopropyl alcohol were added, followed by 0.192 g of catalyst. The autoclave was purged with nitrogen three times to replace the air in the autoclave and then filled with 5 bar of N2. The autoclave was sealed and stirred at a speed of 800 rpm. The temperature was heated to 200 °C and maintained for 2, 4, 6, and 10 h, respectively. The reaction was terminated by cooling to room temperature. The reaction mixture was centrifuged, and the supernatant was taken. Standard solutions of furfural, γ-valerolactone, and the like were prepared. Quantitative analysis was performed using a gas chromatograph, and qualitative analysis was performed using a gas chromatograph-mass spectrometer. The results are listed in Table 1, Nos. 6-9.

[0025] The effect of reaction time on catalytic activity was studied. The increase of reaction time promoted the conversion of FF to GVL. At 200 °C, the conversion of FF remained almost unchanged when the reaction time was extended from 2 h to 8 h, but the yield of GVL increased gradually from 63.3% to 82.6%, which was a significant change. Under shorter reaction time, a large amount of intermediate product IPL and a small amount of by-product 2-furfuryl-5-methylfuran were detected in the product. The yield increased with the increase of reaction time, which indicated that the extension of reaction time was beneficial to the further conversion of intermediate products FFA, IPL, etc. to target products. If the reaction time was further increased to 10 h, IPL was further reduced, and the yield of GVL decreased. In summary, the optimal reaction time was 8 h.

[0026] The corresponding catalysts were prepared according to the method of Examples 1-5.

[0027] Into a 100 mL high-pressure reactor, 0.096 g of furfural and 20 mL of isopropyl alcohol were added, and 0, 0.096, 0.384, 0.576, 0.768 g of catalyst was added, respectively. After replacing the air in the reactor with nitrogen for 3 times, 5 bar of N2 was filled, and the reactor was sealed. The reactor was heated to 200 °C and kept for 8 h with stirring at a speed of 800 rpm. After the reaction was completed, the reaction mixture was cooled to room temperature, and the supernatant was separated by centrifugation. Standard solutions of furfural, γ-valerolactone, etc. were prepared, and quantitative analysis was performed using a gas chromatograph, and qualitative analysis was performed using a gas chromatograph-mass spectrometer. The results are shown in Table 1, Nos. 10-14.

[0028] The effect of catalyst dosage on catalytic activity was investigated. When 96 mg of catalyst was used, FF was also almost completely converted, but as the catalyst dosage increased, the yield of target product GVL showed a trend of first increasing and then decreasing. The highest yield of 88.16% was achieved at a dosage of 384 mg, indicating that sufficient catalyst with more active sites could promote the reaction rate to improve the yield of GVL. At low catalyst dosage, the number of catalytically active species was small, resulting in low conversion and product yield. And a large amount of intermediate product IPL, as well as by-products 2-furfuryl-5-methylfuran and γ-acetylpropyl acetate were detected, resulting in a lower yield of target product. Through mass spectrometric analysis, it was found that with the increase of catalyst dosage, the detectable intermediate product IPL decreased, IPL gradually converted to target product GVL, and by-product γ-acetylpropyl acetate decreased significantly, and the yield of GVL gradually increased; while at high catalyst dosage, the decrease of intermediate product IPL resulted in the decrease of GVL yield due to the conversion of GVL to other products at the available acid sites of the catalyst. In summary, the optimal dosage was 0.384 g.

[0029] The corresponding catalysts were prepared according to the method of Examples 1-5.

[0030] Into a 100 mL autoclave, 0.096 g of furfural and 20 mL of solvent (methanol, ethanol, n-butanol, sec-butanol, respectively) were added, followed by 0.384 g of catalyst, the autoclave was purged with nitrogen three times and then charged with 5 bar of N2, the autoclave was closed, stirred at 800 rpm, heated to 200 °C and maintained for 8 h, the reaction was terminated by cooling to room temperature, the reaction mixture was centrifuged, the supernatant was taken, standard solutions of furfural, γ-valerolactone, etc. were prepared, and quantitative analysis was performed using a gas chromatograph, and qualitative analysis was performed using a gas chromatograph-mass spectrometer, the results are listed in Table 1, Nos. 15-18. Example

[0031] Hydrothermal preparation of catalyst: 1.4 g of ZrOCl2·8H2O was dissolved in 8.8 mL of deionized water under magnetic stirring, and 0.5 g of NH4H2PO4 was dissolved in 4.4 mL of deionized water. The prepared aqueous solution of NH4H2PO4 was added to the aqueous solution of ZrOCl2·8H2O. Subsequently, 0.35 g of H-beta(25) powder was added to the above mixed solution. After the above mixed liquid was transferred to a 50 mL hydrothermal reactor, it was placed in a blast drying oven at 110 °C for 24 h, then the mixed liquid was taken out, the solid catalyst was separated by rotary evaporation at 60 °C, the recovered solid catalyst was dried overnight at 105 °C, and calcined at 400 °C at a heating rate of 5 °C / min under air in a muffle furnace for 4 h to obtain the catalyst, which is denoted as ZPB1.0(441) b .

[0032] Into a 100 mL autoclave, 0.096 g of furfural and 20 mL of isopropanol were added, followed by 0.192 g of catalyst, the autoclave was purged with nitrogen three times and then charged with 5 bar of N2, the autoclave was closed, stirred at 800 rpm, heated to 170 °C and maintained for 8 h, the reaction was terminated by cooling to room temperature, the reaction mixture was centrifuged, the supernatant was taken, standard solutions of furfural, γ-valerolactone, etc. were prepared, and quantitative analysis was performed using a gas chromatograph, and qualitative analysis was performed using a gas chromatograph-mass spectrometer, the results are listed in Table 1, No. 19.

[0033] ZrOCl2*8H2O (0.7-2.8 g) was dissolved in 8.8 mL of deionized water under magnetic stirring, while 0.5 g of NH4H2PO4was dissolved in 4.4 mL of deionized water. The prepared aqueous solution of NH4H2PO4was slowly added to the aqueous solution of ZrOCl2*8H2O under vigorous stirring. The solution was stirred vigorously at room temperature for 6 h. The obtained suspension was separated by rotary evaporation at 60 °C to isolate the solid catalyst. Then, the recovered solid was dried at 105 °C overnight and calcined in a muffle furnace under air at a heating rate of 5 °C / min up to 400 °C for 4 h to obtain the catalyst, noted as ZrPX (adjusting the amount of ZrOCl2*8H2O and NH4H2PO4, catalysts with X = 0.5, 1.0, 2.0 were prepared, respectively).

[0034] ZrP1.0 prepared above was mixed with H-beta zeolite at a mass ratio of 4:1 to obtain a catalyst with a total mass of 192 mg, noted as ZrP1.0 / H-beta.

[0035] Into a 100 mL high-pressure reactor, 0.096 g of furfural and 20 mL of isopropanol were added, followed by 0.192 g of catalyst. After the reactor was purged with nitrogen three times to replace the air therein, 5 bar of N2was charged, and the reactor was sealed. The stirring speed was set at 800 rpm, and the reactor was heated to 170 °C and maintained for 8 h. After the reaction was completed, the reactor was cooled to room temperature. The reaction mixture was centrifuged, and the supernatant was collected. Standard solutions of furfural, γ-valerolactone, and the like were prepared, and quantitative analysis was performed using a gas chromatograph, while qualitative analysis was performed using a gas chromatograph-mass spectrometer. The results are shown in Table 1, entries 20-24.

[0036] ZrOCl2*8H2O (0.7-2.8 g) was dissolved in 8.8 mL of deionized water under magnetic stirring, while 0.5 g of NH4H2PO4was dissolved in 4.4 mL of deionized water. The prepared aqueous solution of NH4H2PO4was slowly added to the aqueous solution of ZrOCl2*8H2O under vigorous stirring. Subsequently, 0.35 g of H-beta (25) powder was added to the above mixed solution, and the mixture was stirred vigorously at room temperature for 6 h. The obtained suspension was separated by rotary evaporation at 60 °C to isolate the solid catalyst. Then, the recovered solid catalyst was dried at 105 °C overnight and calcined in a muffle furnace under air at a heating rate of 5 °C / min up to 400 °C for 4 h to obtain the catalyst ZPBX. Here, X = 0.5-2.0, i.e., the molar ratio of ZrOCl2*8H2O and NH4H2PO4was controlled to be 0.5-2.0, and the catalysts were noted as ZPB0.5, ZPB1.0, and ZPB2.0.

[0037] Dissolve 1.4 g ZrOCl2·8H2O in 8.8 mL deionized water under magnetic stirring, while dissolving 0.5 g NH4H2PO4 in 4.4 mL deionized water. Under vigorous stirring, slowly drop the prepared aqueous solution of NH4H2PO4 into the aqueous solution of ZrOCl2·8H2O, then add a certain amount of H-beta(25) powder into the above mixed solution, and stir vigorously at room temperature for 6 h. The obtained suspension is separated by rotary evaporation at 60 °C to isolate the solid catalyst, then the recovered solid is dried at 105 °C overnight, and calcined in a muffle furnace under air at a heating rate of 5 °C / min to 400 °C for 4 h to obtain the catalyst ZPBX (xyz). Here, control X = 1, i.e. the molar ratio of ZrOCl2·8H2O and NH4H2PO4 is 1; control x / z, i.e. the mass ratio of ZrOCl2·8H2O and H-beta(25) = 0.5:1, 2:1, 3:1, 4:1, 5:1, 6:1 and 8:1, respectively, to prepare the catalyst ZPB1.0(112); ZPB1.0(221), ZPB1.0(331), ZPB1.0(441), ZPB1.0(551), ZPB1.0(661) and ZPB1.0(881).

[0038] Into a 100 mL high-pressure reactor, 0.096 g of furfural and 20 mL of isopropyl alcohol were added, followed by 0.192 g of catalyst. After replacing the air in the reactor with nitrogen for 3 times and filling with 5 bar of N2, the reactor was sealed and stirred at a speed of 800 rpm. It was heated to 170 °C and kept for 8 h. After the reaction was completed, the reaction mixture was cooled to room temperature. The supernatant was separated by centrifugation. Standard solutions of furfural, γ-valerolactone, etc. were prepared. Quantitative analysis was performed using a gas chromatograph, and qualitative analysis was performed using a gas chromatograph-mass spectrometer. The results are shown in Table 1, Nos. 25-34.

[0039] Table 1, Nos. 25-27, investigates the effect of Zr / P on catalytic activity. When the molar ratio of Zr / P is 0.5, the conversion rate of FF can reach 73.04%, and the yield is only 0.13%. The main product is intermediate product IPL. When the molar ratio of Zr / P increases to 1, the conversion rate of FF increases to 99.91%, and the yield of the product increases to a maximum of 50.94%. Continue to increase the molar ratio of Zr / P, when the molar ratio of Zr / P is 2, the conversion rate of substrate FF is almost unchanged, but the yield of the product slowly decreases to 46.27%. Mass spectrometric analysis shows that the etherification product EMF of FFA, furfuryl ethyl ether, increases, and the yield of intermediate product IPL decreases. The reason may be that the acid-base properties of the catalyst change. Therefore, the molar ratio of Zr / P is 1, which is the optimal ratio.

[0040] Table 1, No. 28-34, explores the effect of the mass ratio of Zr precursor to H-beta zeolite on catalytic activity. The mass ratio is explored from 0.5 to 8, and low loading of ZrP is beneficial to the formation of IPL. With the change of loading, the conversion rate of FF can reach a high level, all close to 100%, but with the increase of ZrP loading, the yield and selectivity of target product GVL show a trend of first increasing and then decreasing, reaching the highest at a mass ratio of 4, with a GVL yield of 64.16%. When the mass ratio of Zr precursor to H-beta is 8, the GVL yield decreases to 52.76%, because the acid-base ratio of the catalyst is not suitable, resulting in an increase in the etherification product EMF of FFA, furfuryl ethyl ether, and the intermediate product IPL, but the target product GVL is not generated in time through dehydration or hydrolysis cyclization, resulting in a decrease in the yield of the target product GVL. In summary, ZPB1.0(441) is the preferred catalyst.

[0041] Into a 100 mL high-pressure reactor, 0.096 g of furfural and 20 mL of isopropyl alcohol were added, followed by 0.384 g of catalyst. After replacing the air in the reactor with nitrogen for 3 times, 5 bar of N2 was filled, and the reactor was sealed. The reactor was stirred at a speed of 800 rpm, heated to 200°C and kept for 8 h, and then cooled to room temperature. The reaction mixture was separated, and the catalyst was dried at 105°C for 2 h, then taken out for repeated experiments, and so on for a total of 5 times. In the last cycle, the catalyst was calcined in a muffle furnace under air at a heating rate of 5°C / min to 400°C for 4 h. After each reaction, the reaction mixture was centrifuged, and the supernatant was taken. Standard solutions of furfural and γ-valerolactone were prepared, and quantitative analysis was performed using a gas chromatograph, and qualitative analysis was performed using a gas chromatograph-mass spectrometer. The results are shown in Table 1, No. 35-40. The first cycle to the fifth cycle correspond to Examples 35-39, respectively.

[0042] After 6 cycles of reaction, the catalyst was separated, and the metal ions in the reaction solution were detected by ICP-OES. The results showed that the concentration of Zr in the reaction solution was 0.0071 mg / L, and the concentration of P was 0.076 mg / L, both of which were lower than the detection limit of the instrument, indicating that the catalyst had almost no loss and was relatively stable.

[0043] The reusability of the catalyst was explored. After each test, the reaction liquid was first taken out, and then the reactor body was placed in a drying oven for drying. After drying, the catalyst was taken out and directly used for the next test. With the increase of the cycle number, the conversion rate of the substrate FF remained almost unchanged, but the yield of GVL was continuously decreasing. After the fifth cycle, the yield was reduced by about 25%. Before the sixth run, the recovered catalyst was calcined at 400°C for 4 h, and the catalytic performance was obviously improved. The conversion rate of FF could reach 98.9%, almost restored to the state of the fresh catalyst, and the yield of GVL was restored to 78.11%. After calcination, the catalyst had excellent stability.

[0044] Table 1 Example 1-40 test results

[0045]

[0046]

[0047] The above description is only the preferred embodiment of the present application, and therefore cannot limit the scope of the present application. Any equivalent changes and modifications made according to the scope of the present patent and the content of the specification should still be within the scope of the present application.

Claims

1. A zirconium phosphate supported H-Beta-25 molecular sieve catalyst for one-pot synthesis of γ-valerolactone from furfural, characterized in that: Zirconium phosphate supported H-beta-25 molecular sieve catalyst was prepared as follows: 1.4 g of ZrOCl2·8H2O was dissolved in 8.8 mL of deionized water under magnetic stirring, while 0.5 g of NH4H2PO4 was dissolved in 4.4 mL of deionized water; under vigorous stirring, the prepared aqueous solution of NH4H2PO4 was slowly added dropwise into the aqueous solution of ZrOCl2·8H2O; then, 0.35 g of H-beta-25 powder was added into the above mixed solution; after the mixed solution was stirred vigorously at room temperature for 6 h, the excess water was removed by rotary evaporation at 60°C, and the obtained solid was dried at 105°C overnight; then the dried solid was ground, put into a muffle furnace, calcined at 400°C under air with a heating rate of 5°C / min for 4 h to obtain the zirconium phosphate supported H-beta-25 molecular sieve catalyst; The application of the zirconium phosphate supported H-beta-25 molecular sieve catalyst in the one-pot synthesis of gamma-valerolactone from furfural, and the specific application method is as follows: 0.096 g of furfural and 20 mL of isopropyl alcohol were added into a 100 mL high-pressure reaction kettle, then 0.384 g of the zirconium phosphate supported H-beta-25 molecular sieve catalyst was added, the air in the kettle was replaced with nitrogen for 3 times, 5 bar of N2 was filled, the reaction kettle was sealed and stirred at a speed of 800 rpm, heated to 200°C and kept for 8 h, and after the reaction was completed, the reaction kettle was cooled at room temperature to obtain gamma-valerolactone.

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