A method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethylfurfural

Abstract

The invention discloses a method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethylfurfural. The method comprises: after 5-hydroxymethylfurfural, a bimetallic supported catalyst, a solvent and hydrogen are fully mixed in a fixed bed reactor, a hydrogenation reaction occurs, and 2,5-tetrahydrofuran dimethanol is prepared. The preparation method of the present invention catalyzes 5-hydroxymethylfurfural to prepare 2,5-tetrahydrofuran dimethanol by one-step hydrogenation through the synergistic effect of a bimetallic supported catalyst and a fixed bed reactor, which is beneficial to improving the conversion rate and selectivity of the chemical reaction, and the catalyst has good stability and has broad prospects for industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemicals, and specifically relates to a method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethylfurfural. Background Art

[0002] 2,5-Tetrahydrofuran dimethanol (THFDM) is an important bio-based chemical. Its molecular formula has an oxygen-containing rigid ring structure and a symmetrical diol functional group. Its molecular stability is significantly higher than that of unsaturated furan ring compounds. It can be used in solvents, surfactants, bio-based polyesters and other fields. THFDM is mainly made from 5-hydroxymethylfurfural (HMF), a bio-based platform chemical. 2,5-furan dimethanol (FDM) is first produced by selective catalytic hydrogenation of HMF, which is then separated and refined and then hydrogenated to THFDM, i.e., a two-step process. However, the separation and refining of FDM is complicated, and it is easily lost during the refining process due to its thermal instability. The use of a catalyst with both aldehyde hydrogenation and furan ring hydrogenation functions can directly hydrogenate HMF to THFDM, thereby avoiding the separation and purification of intermediate products, but there is also the problem of low THFDM yield.

[0003] S. Fulignati et al. prepared THFDM by hydrogenation of HMF catalyzed by Ru / C, Pd / C and Pt / C, among which Ru / C catalyst had good catalytic performance and the THFDM yield could reach 95% (Appl. Catal., A2019, 578, 122-133). However, due to the high cost of the precious metal Ru and the problem of loss of active components, the practical application of this type of catalyst is limited. Patent CN113773284A discloses a method for preparing THFDM by catalytic hydrogenation of HMF by Ni-Co / SiO2. Although the catalyst is significantly lower in cost than the precious metal catalyst, the THFDM yield is only 83%, which also increases the difficulty of purifying subsequent products. In addition, in the process of catalyst preparation, it is difficult to achieve uniform microscopic mixing due to the limitation of the structure of the stirring tank equipment by the traditional coprecipitation method, so the catalyst grain size is unevenly distributed, and it is difficult to achieve high dispersion of active components. At present, HMF hydrogenation and FDM hydrogenation mostly use intermittent reactor reactors, which have problems such as complex operation and low production efficiency. The fixed bed process can achieve continuous flow synthesis of the target product, but there is still little research on the direct preparation of THFDM by catalytic hydrogenation of HMF in a fixed bed reactor. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethyl furfural, so as to overcome the shortcomings of the prior art.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0006] One aspect of the present invention provides a method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethyl furfural, which comprises: fully mixing 5-hydroxymethyl furfural, a bimetallic supported catalyst, a solvent and hydrogen in a fixed bed reactor, and then performing a hydrogenation reaction to prepare 2,5-tetrahydrofuran dimethanol;

[0007] The bimetallic supported catalyst comprises a first active metal, a second active metal and a metal oxide carrier, wherein the first active metal comprises nickel, the second active metal comprises at least any one of copper, zinc, magnesium and cerium, and the metal oxide carrier comprises at least any one of aluminum oxide, silicon oxide and cerium oxide; the mass fraction of the first active metal in the bimetallic supported catalyst is 10% to 50%, the mass fraction of the second active metal is 1% to 20%, and the mass ratio of the first active metal to the second active metal is 1:5 to 5:1.

[0008] Compared with the prior art, the present invention has at least the following beneficial effects:

[0009] (1) The bimetallic supported catalyst of the present invention has a synergistic effect when used in a fixed bed reactor. The catalyst particles filled in the fixed bed reactor form a stationary solid bed layer, and the gaseous reactant flows through the gaps between the catalyst particles and undergoes a chemical reaction on the catalyst surface. This arrangement enables the reactants to fully contact the catalyst, achieving an efficient mass transfer effect, thereby improving the reaction rate and conversion rate; the fixed bed reactor allows hydrogenation reactions to be carried out under mild temperature and high pressure conditions, which are conducive to better coupling of the bimetallic active centers and achieving efficient conversion of the substrate; the bimetallic catalyst can prevent the catalyst from sintering at high temperatures and improve the thermal stability of the catalyst, which is very important for continuous operation in the fixed bed reactor; in addition, the catalyst in the fixed bed reactor is not easy to wear and has a long service life, which is conducive to improving the conversion rate and selectivity of the chemical reaction.

[0010] (2) The present invention uses a bimetallic supported catalyst, which has active centers for hydrogenating 5-hydroxymethylfurfural to produce 2,5-furan dimethanol and hydrogenating 2,5-furan dimethanol to produce 2,5-tetrahydrofuran dimethanol, so that the two reactions are carried out in a fixed bed reactor, the reaction conditions can be adjusted, the process flow can be reduced, and energy consumption can be reduced.

[0011] (3) The present invention adopts a fixed bed process to achieve continuous synthesis of the target product. Under the premise of complete conversion of HMF, the obtained THFDM has high selectivity and the purity can reach more than 99% after rotary evaporation refining. The catalyst has good stability and has broad prospects for industrial application. DETAILED DESCRIPTION

[0012] In view of the above problems existing in the prior art, the inventors of the present invention have conducted extensive and in-depth research and provided a method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethylfurfural.

[0013] The technical solution, its implementation process and principle will be further explained as follows.

[0014] As one aspect of the technical solution of the present invention, a method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethyl furfural comprises: fully mixing 5-hydroxymethyl furfural, a bimetallic supported catalyst, a solvent and hydrogen in a fixed bed reactor, and then performing a hydrogenation reaction to prepare 2,5-tetrahydrofuran dimethanol;

[0015] The bimetallic supported catalyst comprises a first active metal, a second active metal and a metal oxide carrier, wherein the first active metal comprises nickel, the second active metal comprises at least any one of copper, zinc, magnesium and cerium, and the metal oxide carrier comprises at least any one of aluminum oxide, silicon oxide and cerium oxide; the mass fraction of the first active metal in the bimetallic supported catalyst is 10% to 50%, the mass fraction of the second active metal is 1% to 20%, and the mass ratio of the first active metal to the second active metal is 1:5 to 5:1.

[0016] In some embodiments, the mass ratio of 5-hydroxymethylfurfural to hydrogen is 1:5-20.

[0017] In some preferred embodiments, the mass ratio of 5-hydroxymethylfurfural to hydrogen is 1:5-15.

[0018] In some embodiments, the ratio of 5-hydroxymethylfurfural to solvent is 1 g: 25-250 ml.

[0019] In some preferred embodiments, the ratio of 5-hydroxymethylfurfural to solvent is 1 g: 50-150 ml.

[0020] In some particularly preferred embodiments, the ratio of 5-hydroxymethylfurfural to solvent is 1 g: 80-120 ml.

[0021] In some embodiments, the hydrogenation reaction is carried out at a temperature of 120 to 180° C. and for a time of 0.5 to 20 h.

[0022] In some preferred embodiments, the hydrogenation reaction is carried out at a temperature of 120 to 160° C. and for a time of 2 to 20 hours.

[0023] In some embodiments, the pressure of the hydrogenation reaction is 3-5 MPa.

[0024] In some embodiments, the feed mass space velocity of 5-hydroxymethylfurfural in the fixed bed reactor is 0.1 to 0.5 h -1 Wherein, mass space velocity = 5-hydroxymethylfurfural reaction solution concentration × pump speed ÷ catalyst mass.

[0025] In some embodiments, the solvent comprises formaldehyde.

[0026] In some preferred embodiments, the second active metal comprises copper.

[0027] In some preferred embodiments, the metal oxide support comprises alumina.

[0028] In some embodiments, the mass ratio of the first active metal to the second active metal in the bimetallic supported catalyst is 1:5 to 5:1.

[0029] In some embodiments, the mass ratio of the first active metal to the second active metal in the bimetallic supported catalyst is 1.5:1 to 3:1.

[0030] In some embodiments, the fixed bed reactor has an inner diameter of 13 mm.

[0031] In some embodiments, the filler in the fixed bed reactor includes a bimetallic supported catalyst and quartz sand, and the particle size of the filler is 20-40 mesh.

[0032] In some preferred embodiments, the mass ratio of the bimetallic supported catalyst to the quartz sand in the filler is 2-3:5-15.

[0033] In some more preferred embodiments, the mass ratio of the bimetallic supported catalyst to the quartz sand in the filler is 2.3-2.7:8-12.

[0034] In some more specific embodiments, the method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethylfurfural comprises:

[0035] (1) loading the bimetallic supported catalyst into the constant temperature section of a fixed bed reactor;

[0036] (2) the 5-hydroxymethylfurfural is continuously fed into a fixed bed reactor, and after hydrogen is introduced and fully mixed, the bimetallic supported catalyst catalyzes the hydrogenation reaction of the 5-hydroxymethylfurfural at 120-180° C. and 3-5 MPa, and the crude product of the 2,5-tetrahydrofuran dimethanol is obtained after gas-liquid separation;

[0037] (3) The crude product of 2,5-tetrahydrofuran dimethanol is purified by rotary evaporation to obtain 2,5-tetrahydrofuran dimethanol.

[0038] In some more specific embodiments, the method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethylfurfural specifically comprises:

[0039] The bimetallic supported catalyst was loaded into the constant temperature section of the fixed bed reactor, and 5-hydroxymethylfurfural was pumped into the reactor at a rate of 0.1 to 0.5 h. - The feed mass space velocity of 1 is pumped in, and after being vaporized in a vaporizer, it enters the catalyst bed together with hydrogen, and the hydrogenation reaction is carried out at 120-180°C, and the reaction pressure is 3-5MPa. The obtained mixture is condensed in a condenser to achieve gas-liquid separation to obtain a crude 2,5-tetrahydrofuran dimethanol. The crude product is distilled to remove by-products to obtain a high-purity finished 2,5-tetrahydrofuran dimethanol.

[0040] Furthermore, the reaction temperature of the hydrogenation reaction is preferably 140°C, the reaction pressure is preferably 4 MPa, and the 5-hydroxymethylfurfural is heated for 0.1 to 0.5 h. - The feed mass space velocity of 1 is preferably 0.3h - 1.

[0041] The reaction route for preparing 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural is as follows:

[0042]

[0043] The present invention uses metal oxide as a carrier, and loads a catalyst prepared by two active non-precious metals on its surface, thereby realizing the direct catalytic hydrogenation of HMF to prepare THFDM. Among them, the first active metal has hydrogenation activity and is the main active center for hydrogenating HMF to THFDM; the second active metal can promote the dispersion of the first active metal and adjust the acidity and alkalinity of the carrier surface, thereby inhibiting the occurrence of hydrogenation side reactions. Among them, the bimetallic supported catalyst has a synergistic effect when used in a fixed bed reactor. The introduction of the second active component can improve the selectivity of the target product, inhibit the formation of carbon deposits, and reduce the sintering of the active phase, thereby improving the stability and catalyticity of the catalyst. In addition, the present invention uses a bimetallic supported catalyst for catalysis, and has active centers for hydrogenating 5-hydroxymethylfurfural to prepare 2,5-furan dimethanol and hydrogenating 2,5-furan dimethanol to prepare 2,5-tetrahydrofuran dimethanol, so that the two reactions are carried out in a fixed bed reactor, and the reaction conditions can be adjusted, the process flow can be reduced, and energy consumption can be reduced.

[0044] Through the method adopted by the present invention, the conversion rate of the 5-hydroxymethylfurfural is greater than 95%, and the selectivity of the 2,5-tetrahydrofuran dimethanol is greater than 91%.

[0045] In some embodiments, the bimetallic supported catalyst is prepared by high gravity co-precipitation method.

[0046] In some embodiments, the preparation method of the bimetallic supported catalyst includes: reacting a mixed system comprising a metal oxide carrier, a first metal salt solution, a second metal salt solution, and a precipitant in a supergravity reactor, and after aging, filtering, drying, and calcining, reducing and activating the system under a hydrogen atmosphere to obtain a bimetallic supported catalyst.

[0047] Furthermore, the first metal salt solution includes Ni(NO3)2.

[0048] Furthermore, the concentration of the first metal salt solution is 0.05-0.5 mol / L.

[0049] Furthermore, the concentration of the first metal salt solution is 0.169 mol / L.

[0050] Furthermore, the second metal salt solution includes at least any one of Cu(NO3)2, Zn(NO3)2, Mg(NO3)2, Ce(NO3)3, etc., but is not limited thereto.

[0051] Furthermore, the second metal salt solution includes Cu(NO3)2.

[0052] Furthermore, the concentration of the second metal salt solution is 0.05-0.5 mol / L.

[0053] Furthermore, the concentration of the second metal salt solution is 0.147 mol / L.

[0054] Furthermore, the precipitant includes at least any one of Na2CO3, K2CO3, KOH, NaOH or ammonia water, but is not limited thereto.

[0055] Furthermore, the precipitant includes Na2CO3.

[0056] Furthermore, the solution concentration of the precipitant is 0.2-1.0 mol / L.

[0057] Furthermore, the solution concentration of the precipitant is 0.2 mol / L.

[0058] Furthermore, the rotation speed of the supergravity reactor is 200-1300 r / min.

[0059] Furthermore, the rotation speed of the high gravity reactor is 600-800 r / min. Particularly preferably, the rotation speed of the high gravity reactor is 750 r / min.

[0060] Furthermore, the aging temperature is 40-80° C. and the aging time is 4-12 hours.

[0061] Furthermore, the aging temperature is 60° C. and the aging time is 8 hours.

[0062] Furthermore, the drying temperature is 100-150° C. and the drying time is 3-12 hours.

[0063] Furthermore, the drying temperature is 120° C. and the drying time is 5 hours.

[0064] Furthermore, the calcination temperature is 300-600° C. and the calcination time is 3-8 hours.

[0065] Furthermore, the calcination temperature is 450-550°C.

[0066] Furthermore, the reduction activation temperature is 300-500° C. and the time is 3-9 hours.

[0067] Furthermore, the reduction activation temperature is 400° C. and the time is 6 hours.

[0068] In some specific embodiments, the method for preparing the bimetallic supported catalyst may include the following steps:

[0069] The metal oxide carrier is fully mixed with the first metal salt solution A and the second metal salt solution B and stirred for 1 to 3 hours. After being fully dissolved, the mixed solution and the precipitant are poured into the liquid storage tank respectively. After the temperature is raised to 80°C, they are continuously and concurrently flowed into the ultra-gravity reactor. In the reactor, the stock solution is evenly sprayed onto the rotating filler through a liquid distributor under the set high-speed rotation. Under the action of centrifugal force, the two raw liquids are fully contacted and reacted in the filler layer. The liquid-solid phase product generated by the reaction is thrown to the outer edge of the filler, and finally flows to the liquid outlet under the action of gravity and enters the aging tank. At the liquid outlet, the pH value of the precipitate is measured, and the flow rate of the raw liquid is adjusted as needed to maintain the pH value at about 7.5. The obtained precipitate after stirring is further aged at 40-80° C. for 4-12 hours, the precipitate is filtered, dried at 100-150° C. for 3-12 hours, and calcined at 300-600° C. for 3-8 hours; and activated by reducing with hydrogen at 300-500° C. for 3-9 hours to obtain the bimetallic supported catalyst.

[0070] In some more specific embodiments, the method for preparing the bimetallic supported catalyst specifically comprises the following steps:

[0071] The metal oxide carrier is fully mixed with the first metal salt solution A and the second metal salt solution B and stirred for 1 hour. After being fully dissolved, the mixed solution and the precipitant are poured into the liquid storage tank respectively, and the mixture is heated to 80°C and then continuously and concurrently flows into the supergravity reactor. In the reactor, the stock solution is evenly sprayed onto the rotating filler through the liquid distributor under the set high-speed rotation. Under the action of centrifugal force, the two raw material liquids are fully contacted and reacted in the filler layer. The liquid-solid phase product generated by the reaction is thrown to the outer edge of the filler, and finally flows to the liquid outlet under the action of gravity and enters the aging tank. At the liquid outlet, the pH value of the precipitate is measured, and the flow rate of the raw material liquid is adjusted as needed to maintain the pH value at about 7.5. After stirring, the obtained precipitate is further aged at 55°C for 10 hours, the precipitate is filtered, and dried at 105°C for 8 hours, and calcined at 400-500°C for 5 hours; it is activated by reducing with hydrogen at 350°C for 4 hours to obtain the bimetallic supported catalyst.

[0072] The mass of the first active metal is preferably 20 wt % of the total mass of the bimetallic supported catalyst, and the mass of the second active metal is preferably 10 wt % of the total mass of the bimetallic supported catalyst.

[0073] The bimetallic supported catalyst prepared by ultra-gravity co-precipitation method has uniform grain size distribution, achieving high dispersion of active metal components and thus improving catalytic performance.

[0074] In summary, the present invention catalyzes the one-step hydrogenation of HMF to prepare THFDM through the synergistic effect of a bimetallic supported catalyst and a fixed bed reactor. Under the premise of complete conversion of HMF, the obtained THFDM has high selectivity, and the purity can reach more than 99% after rotary evaporation refining. The catalyst has good stability and has broad prospects for industrial application.

[0075] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Those skilled in the art can make modifications or equivalent substitutions based on the understanding of the technical scheme of the present invention without departing from the spirit and scope of the technical scheme of the present invention, and all should be included in the protection scope of the present invention.

[0076] If the specific experimental steps or conditions are not specified in the embodiments, the operation or conditions of the conventional experimental steps described in the literature in the art can be carried out. If the manufacturer is not specified for the reagents or instruments used, they can be obtained commercially. Exemplarily, the raw materials and catalysts in the embodiments of the present invention are purchased through commercial channels, all purchased from Adamas Group Chemical Reagent Co., Ltd. Unless otherwise specified, the test methods all use conventional methods, and the instrument settings all use the settings recommended by the manufacturer, wherein the composition (purity) analysis method of the product and the mother liquor uses Agilent's 8860 high-performance gas chromatograph to analyze the products in the 5-hydroxymethylfurfural synthesis reaction.

[0077] Example 1

[0078] Preparation of bimetallic supported catalysts:

[0079] Accurately weigh 49.09g of Ni(NO3)2·6H2O and 35.461g of Cu(NO3)2·3H2O, transfer to a 1L volumetric flask, and dilute to the mark with purified water, where the concentration of Ni(NO3)2·6H2O is 0.169mol / L, and the concentration of Cu(NO3)2·3H2O is 0.147mol / L. Accurately weigh 50.0g of Al2O3, add it to the above solution, stir at room temperature for 1h, then slowly drop 0.2mol / L of Na2CO3 aqueous solution into it, pour it into a liquid storage tank, heat it to 80℃ and continue to flow into the ultragravity reactor. Control the final solution pH=7.5. Then continue aging at 55℃ for 10h, filter the product precipitate, dry it at 105℃ for 8h, and calcine it at 400℃ for 5h to obtain a solid product. Then continue to reduce it in a hydrogen atmosphere at 350℃ for 4h to obtain Ni 20 -Cu 10 / Al2O3 catalyst, the theoretical loading amount of Ni is 20wt%, and the theoretical loading amount of Cu is 10wt%.

[0080] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural:

[0081] Catalyst 1 was tableted, crushed, and sieved into 20-40 meshes. 2.5 g of catalyst and 7.5 g of quartz sand were loaded into a fixed bed reactor with an inner diameter of 13 mm. 10 g of 5-hydroxymethylfurfural was added to 1 L of methanol as a reaction substrate. The reaction was evaluated under a hydrogen pressure of 4 MPa and a reaction temperature of 140°C. The molar ratio of hydrogen to 5-hydroxymethylfurfural was 8:1, and the feed volume space velocity of 5-hydroxymethylfurfural was 0.3 h-1. The reaction liquid data after 2 hours of reaction are shown in Table 1.

[0082] Example 2

[0083] Preparation of bimetallic supported catalysts:

[0084] Accurately weigh 35.40g of Ni(NO3)2·6H2O and 54.31g of Cu(NO3)2·3H2O, transfer to a 1L volumetric flask, and dilute to the mark with pure water to obtain a Ni(NO3)2·6H2O concentration of 0.169mol / L and a Cu(NO3)2·3H2O concentration of 0.225mol / L. Other steps are the same as in Example 1 to obtain catalyst 2, with a theoretical loading of Ni of 10wt% and a theoretical loading of Cu of 20wt%.

[0085] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 10 -Cu 20 / Al2O3 catalyst.

[0086] Example 3

[0087] Preparation of bimetallic supported catalysts:

[0088] Accurately weigh 91.25g of Ni(NO3)2·6H2O and 46.094g of Cu(NO3)2·3H2O, transfer to a 1L volumetric flask, and dilute to the mark with pure water to obtain a Ni(NO3)2·6H2O concentration of 0.314mol / L and a Cu(NO3)2·3H2O concentration of 0.191mol / L. Other steps are the same as in Example 1, to obtain catalyst 3, wherein the theoretical loading of Ni is 30wt%, and the theoretical loading of Cu is 10wt%.

[0089] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 30 -Cu 10 / Al2O3 catalyst.

[0090] Example 4

[0091] Preparation of bimetallic supported catalysts:

[0092] Accurately weigh 60.14g of Ni(NO3)2·6H2O and 19.27g of Cu(NO3)2·3H2O, transfer to a 1L volumetric flask, and dilute to the mark with pure water to obtain a Ni(NO3)2·6H2O concentration of 0.207mol / L and a Cu(NO3)2·3H2O concentration of 0.080mol / L. Other conditions are the same as in Example 1 to obtain catalyst 4, with a theoretical loading of Ni of 30wt% and a theoretical loading of Cu of 5wt%.

[0093] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 30 -Cu5 / Al2O3 catalyst.

[0094] Example 5

[0095] Preparation of bimetallic supported catalyst: The precipitant was replaced by ammonia water with a concentration of 0.2 mol / L, and the other conditions were the same as those in Example 1 to obtain Ni 20 -Cu 10 / Al2O3-1 catalyst.

[0096] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Cu 10 / Al2O3-1 catalyst.

[0097] Example 6

[0098] Preparation of bimetallic supported catalyst: replace the precipitant with KOH aqueous solution from Na2CO3, KOH concentration is 0.2 mol / L, and other conditions are the same as in Example 1 to obtain Ni 20 -Cu 10 / Al2O3-2 catalyst.

[0099] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Cu 10 / Al2O3-2 catalyst.

[0100] Example 7

[0101] Preparation of bimetallic supported catalyst: The precipitant was replaced by Na2CO3 with NaOH aqueous solution, the NaOH concentration was 0.2 mol / L, and the other conditions were the same as in Example 1 to obtain Ni 20 -Cu 10 / Al2O3-3 catalyst.

[0102] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Cu 10 / Al2O3-3 catalyst.

[0103] Example 8

[0104] Preparation of bimetallic supported catalyst: The catalyst calcination temperature was 300°C, and the other conditions were the same as in Example 1 to obtain Ni20 -Cu 10 / Al2O3-a catalyst.

[0105] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Cu 10 / Al2O3-a catalyst.

[0106] Example 9

[0107] Preparation of bimetallic supported catalyst: The catalyst calcination temperature was 350°C, and the other conditions were the same as in Example 1 to obtain Ni 20 -Cu 10 / Al2O3-b catalyst.

[0108] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Cu 10 / Al2O3-b catalyst.

[0109] Example 10

[0110] Preparation of bimetallic supported catalyst: The catalyst calcination temperature was 450°C, and the other conditions were the same as in Example 1 to obtain Ni 20 -Cu 10 / Al2O3-c catalyst.

[0111] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Cu 10 / Al2O3-c catalyst.

[0112] Embodiment 11

[0113] Preparation of bimetallic supported catalyst: The catalyst calcination temperature was 500°C, and the other conditions were the same as in Example 1 to obtain Ni 20 -Cu 10 / Al2O3-d catalyst.

[0114] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Cu 10 / Al2O3-d catalyst.

[0115] Comparative Example 1

[0116] Preparation of bimetallic supported catalyst: Only Cu was loaded, 81.46 g Cu(NO3)2·3H2O was accurately weighed, transferred to a 1 L volumetric flask, and the volume was fixed to the mark with pure water, wherein the concentration of Cu(NO3)2·H2O was 0.337 mol / L. Others were the same as in Example 1, except that the theoretical mass fraction of Cu was 30 wt%, and Cu was obtained. 30 / Al2O3 catalyst.

[0117] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Cu 30 / Al2O3 catalyst.

[0118] Comparative Example 2

[0119] Preparation of bimetallic supported catalyst: Only Ni is loaded, 106.17 g Ni(NO3)2·6H2O is accurately weighed, transferred to a 1L volumetric flask, and the volume is fixed to the mark with pure water, wherein the concentration of Ni(NO3)2·6H2O is 0.365 mol / L. The theoretical mass fraction of Ni is 30 wt%, and the other parts are the same as in Example 1, to obtain Ni 30 / Al2O3 catalyst.

[0120] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the metal supported catalyst used is Ni 30 / Al2O3 catalyst.

[0121] Table 1 Performance results of catalytic hydrogenation of 5-hydroxymethylfurfural to produce 2,5-tetrahydrofuran dimethanol

[0122]

[0123]

[0124] From the comparison of Examples 1, 2, 3 and 4 in Table 1, it can be seen that the Ni-Cu / Al2O3 catalyst has the best performance when the Ni loading is 20% and the Cu loading is 10%. If the Ni loading is too high, part of the metal Cu will be covered, resulting in insufficient Cu active centers for the hydrogenation of 5-hydroxymethylfurfural; if the Cu loading is too high, there will be insufficient Ni active centers for the subsequent hydrogenation of 2,5-furan dimethanol; Comparison of Examples 1, 5, 6 and 7 shows that when Na2CO3 is used as a precipitant, the conversion rate of 5-hydroxymethylfurfural and the selectivity of 2,5-furan dimethanol are high. Comparison of Examples 1, 8 and 9, the best effect is achieved at a calcination temperature of 400-500°C. When the calcination temperature is low, the metal nitrate is not completely decomposed. As can be seen from Comparative Example 1, when only Cu is loaded, the conversion rate of 5-hydroxymethylfurfural and the product selectivity are poor. It can be seen from Comparative Example 2 that the catalyst only loads metal Ni, and the 5-hydroxymethylfurfural conversion rate and 2,5-tetrahydrofuran dimethanol selectivity are both high. Therefore, Ni is also the active center for the hydrogenation of 5-hydroxymethylfurfural to 2,5-furan dimethanol. However, if the reaction is carried out for a long time, the catalyst will produce sintering of the active phase and form carbon deposits, thereby reducing the stability and catalytic activity of the catalyst. Therefore, it is necessary to add a second metal active center to reduce the carbon deposition phenomenon.

[0125] Example 12

[0126] Preparation of bimetallic supported catalyst: Accurately weigh 52.09g of Ni(NO3)2·6H2O and 29.95g of Zn(NO3)2·6H2O, transfer to a 1L volumetric flask, and dilute to the mark with purified water to obtain a Ni(NO3)2·6H2O concentration of 0.179mol / L and a Zn(NO3)2·6H2O concentration of 0.101mol / L. Other conditions are the same as in Example 1. 20 -Zn 10 / Al2O3, the theoretical loading amount of Ni is 20wt%, and the theoretical loading amount of Zn is 10wt%.

[0127] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Zn 10 / Al2O3.

[0128] Embodiment 13

[0129] Preparation of bimetallic supported catalyst: Accurately weigh 48.94g of Ni(NO3)2·6H2O and 31.16g of Mg(NO3)2·6H2O, transfer to a 1L volumetric flask, and dilute to the mark with purified water, wherein the concentration of Ni(NO3)2·6H2O is 0.168mol / L, and the concentration of Mg(NO3)2·6H2O is 0.122mol / L. Other conditions are the same as those in Example 1, and the catalyst Ni is obtained. 20 -Mg 10 / Al2O3, the theoretical loading amount of Ni is 20wt%, and the theoretical loading amount of Mg is 10wt%.

[0130] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Mg 10 / Al2O3.

[0131] Embodiment 14

[0132] Preparation of bimetallic supported catalyst: Accurately weigh 59.26g of Ni(NO3)2·6H2O and 23.37g of Ce(NO3)3·6H2O, transfer to a 1L volumetric flask, and dilute to the mark with purified water, wherein the concentration of Ni(NO3)2·3H2O is 0.204mol / L, and the concentration of Ce(NO3)3·6H2O is 0.054mol / L. Other contents are the same as in Example 1, and the catalyst Ni is obtained. 20 -Ce 10 / Al2O3, the theoretical loading amount of Ni is 20wt%, and the theoretical loading amount of Ce is 10wt%.

[0133] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural: The operation steps are the same as those in Example 1, except that the bimetallic supported catalyst used is Ni 20 -Ce 10 / Al2O3.

[0134] Comparative Example 3

[0135] A commonly used fixed bed catalyst Ni-6052 commercially available from Adamas Group Chemical Reagent Co., Ltd. was used as a comparative example, and other operations were the same as those of comparative example 1.

[0136] Table 2 Performance results of different catalysts for hydrogenation of 5-hydroxymethylfurfural to 2,5-tetrahydrofuran dimethanol

[0137]

[0138] It can be seen from Examples 1, 12-14 that Cu has a relative advantage as the active metal of B salt. In addition, compared with the commonly used fixed bed catalysts on the market, Ni 20 -Cu 10 / Al2O3 has a higher selectivity for 2,5-tetrahydrofuran dimethanol. The stability of the commonly used fixed bed catalysts on the market is even worse, and the catalytic performance for the hydrogenation of 5-hydroxymethylfurfural decreases after the reaction lasts for more than 15 hours.

[0139] Embodiment 15

[0140] 2.5 g of Ni was loaded into the constant temperature zone of the fixed bed reactor. 20 -Cu 10 / Al2O3. The effects of different reaction conditions on the one-step hydrogenation of 5-hydroxymethylfurfural to 2,5-tetrahydrofuran dimethanol were investigated. The data results are shown in Table 3.

[0141] Comparative Example 4

[0142] The reaction temperature was set to 100°C, and other operations were the same as in Example 1. The data results are shown in Table 3.

[0143] Comparative Example 5

[0144] The hydrogen-to-aldehyde ratio was changed to 5, and the other operations were the same as in Example 1. The data results are shown in Table 3.

[0145] Table 3 Effect of reaction conditions on the hydrogenation of 5-hydroxymethylfurfural to produce 2,5-tetrahydrofuran dimethanol

[0146]

[0147] Table 3 shows the effects of different reaction conditions on the performance of 5-hydroxymethylfurfural hydrogenation to 2,5-tetrahydrofuran dimethanol. The reaction temperature is 140 °C, the mass space velocity of furfural feed is 0.3 h - 1. When the hydrogen-formaldehyde molar ratio is 8.0, the conversion rate of 5-hydroxymethylfurfural is close to 100%, and the selectivity of 2,5-tetrahydrofuran dimethanol reaches 96.9%. When the reaction temperature is low, 5-hydroxymethylfurfural cannot be completely converted. When the reaction temperature is high, 2,5-tetrahydrofuran dimethanol further opens the ring to form by-products, resulting in a decrease in the selectivity of 2,5-tetrahydrofuran dimethanol. When the mass space velocity of the 5-hydroxymethylfurfural feed is too high, 5-hydroxymethylfurfural cannot be completely converted. When the hydrogen-formaldehyde molar ratio is low, 5-hydroxymethylfurfural is difficult to be completely converted. When the hydrogen-formaldehyde molar ratio is too high, 2,5-tetrahydrofuran dimethanol is prone to excessive hydrogenation and ring-opening reaction. A hydrogen-formaldehyde molar ratio of 8.0 is more appropriate.

[0148] Example 16

[0149] Ni 20 -Cu 10The preparation of / Al2O3 catalyst is the same as that in Example 1.

[0150] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural:

[0151] Ni 20 -Cu 10 / Al2O3 catalyst was tableted, crushed, and sieved into 20-40 meshes. 2.5 g of catalyst and 7.5 g of quartz sand were loaded into a fixed bed reactor with an inner diameter of 13 mm. 10.0 g of 5-hydroxymethylfurfural was added to 1.5 L of methanol as a reaction substrate. The rest was the same as in Example 1.

[0152] Embodiment 17

[0153] Ni 20 -Cu 10 The preparation of / Al2O3 catalyst is the same as that in Example 1.

[0154] Preparation of 2,5-tetrahydrofuran dimethanol by hydrogenation of 5-hydroxymethylfurfural:

[0155] Ni 20 -Cu 10 / Al2O3 catalyst was tableted, crushed, and sieved into 20-40 meshes. 2.5 g of catalyst and 7.5 g of quartz sand were loaded into a fixed bed reactor with an inner diameter of 13 mm. 10.1 g of 5-hydroxymethylfurfural was added to 500 mL of methanol as a reaction substrate. Others were the same as in Example 1. The data results are shown in Table 4.

[0156] Table 4 Performance results of 5-hydroxymethylfurfural hydrogenation to 2,5-tetrahydrofuran dimethanol catalyzed by different substrate concentrations

[0157]

[0158] Table 4 shows the effect of different substrate concentrations on the performance of 5-hydroxymethylfurfural hydrogenation to prepare 2,5-tetrahydrofuran dimethanol. If the concentration is too high, the conversion rate of 5-hydroxymethylfurfural is not high. If the concentration is too low, more intermediates are likely to be produced.

[0159] The reaction liquid obtained in Example 1 was used as a typical representative to purify THFDM. The liquid after rotary evaporation was pure THFDM with a purity of up to 99.99%.

[0160] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all aspects and are not intended to limit the present invention, the scope of the present invention is defined only by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0161] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0162] Although the present invention has been described with reference to illustrative embodiments, it will be appreciated by those skilled in the art that various other changes, omissions and / or additions may be made without departing from the spirit and scope of the present invention and that the elements of the embodiments may be replaced by substantial equivalents. In addition, many modifications may be made without departing from the scope of the present invention to adapt specific circumstances or materials to the teachings of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for performing the present invention, but it is intended that the present invention will include all embodiments within the scope of the appended claims. In addition, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

1. A method for preparing 2,5-tetrahydrofuran dimethanol by hydrogenating 5-hydroxymethylfurfural, characterized in that: After 5-hydroxymethylfurfural, a bimetallic supported catalyst, a solvent and hydrogen are fully mixed in a fixed bed reactor, a hydrogenation reaction occurs, and 2,5-tetrahydrofuran dimethanol is prepared; The bimetallic supported catalyst comprises a first active metal, a second active metal and a metal oxide carrier, wherein the first active metal comprises nickel, the second active metal comprises at least any one of copper, zinc, magnesium and cerium, and the metal oxide carrier comprises at least any one of aluminum oxide, silicon oxide and cerium oxide; the mass fraction of the first active metal in the bimetallic supported catalyst is 10% to 50%, the mass fraction of the second active metal is 1% to 20%, and the mass ratio of the first active metal to the second active metal is 1:5 to 5:

1.

2. The method according to claim 1, characterized in that: The mass ratio of 5-hydroxymethylfurfural to hydrogen is 1:5-20, preferably 1:5-15; And / or, the ratio of 5-hydroxymethylfurfural to solvent is 1 g: 25-250 ml, preferably 1 g: 50-150 ml, and particularly preferably 1 g: 80-120 ml.

3. The method according to claim 1, characterized in that: The temperature of the hydrogenation reaction is 120-180°C and the time is 0.5-20h; Preferably, the temperature of the hydrogenation reaction is 120-160°C and the time is 2-20h; And / or, the pressure of the hydrogenation reaction is 3-5 MPa; And / or, the feed mass space velocity of the 5-hydroxymethylfurfural in the fixed bed reactor is 0.1 to 0.5 h -1 ; and / or, the solvent comprises formaldehyde; And / or, the second active metal comprises copper.

4. The method according to claim 1, characterized in that: The filler in the fixed bed reactor includes a bimetallic supported catalyst and quartz sand, and the particle size of the filler is 20 to 40 meshes; Preferably, the mass ratio of the bimetallic supported catalyst to the quartz sand in the filler is 2-3:5-15.

5. The method according to claim 1, characterized in that include: The bimetallic supported catalyst is loaded into the constant temperature section of the fixed bed reactor; The 5-hydroxymethylfurfural is continuously fed into a fixed bed reactor, and after hydrogen is introduced and fully mixed, the bimetallic supported catalyst catalyzes the hydrogenation reaction of 5-hydroxymethylfurfural at 120-180° C. and 3-5 MPa, and the crude product of 2,5-tetrahydrofuran dimethanol is obtained after gas-liquid separation; Preferably, the method further comprises: refining the crude 2,5-tetrahydrofuran dimethanol by rotary evaporation to obtain 2,5-tetrahydrofuran dimethanol.

6. The method according to claim 1, characterized in that: The conversion rate of the 5-hydroxymethylfurfural is greater than 95%, and the selectivity of the 2,5-tetrahydrofuran dimethanol is greater than 91%.

7. The method according to claim 1, characterized in that: The bimetallic supported catalyst is prepared by a supergravity co-precipitation method.

8. The method according to claim 1 or 7, characterized in that: The preparation method of the bimetallic supported catalyst comprises: reacting a mixed system including a metal oxide carrier, a first metal salt solution, a second metal salt solution and a precipitant in a supergravity reactor, and after aging, filtering, drying and calcining, performing reduction activation in a hydrogen atmosphere to obtain a bimetallic supported catalyst.

9. The method according to claim 8, characterized in that: The first metal salt solution includes Ni(NO3)2; and / or, the concentration of the first metal salt solution is 0.05 to 0.5 mol / L; and / or, the second metal salt solution comprises at least any one of Cu(NO3)2, Zn(NO3)2, Mg(NO3)2, Ce(NO3)3, preferably Cu(NO3)2; And / or, the concentration of the second metal salt solution is 0.05-0.5 mol / L.

10. The method according to claim 8, characterized in that: The precipitant includes at least one of Na2CO3, K2CO3, KOH, NaOH or ammonia water, preferably Na2CO3; and / or, the solution concentration of the precipitant is 0.2 to 1.0 mol / L; And / or, the rotation speed of the high gravity reactor is 200 to 1300 r / min, preferably 600 to 800 r / min; And / or, the aging temperature is 40-80°C and the time is 4-12h; And / or, the drying temperature is 100-150° C. and the drying time is 3-12 hours; And / or, the calcination temperature is 300-600°C, and the time is 3-8h. Preferably, the calcination temperature is 450-550°C; And / or, the reduction activation temperature is 300-500° C. and the time is 3-9 hours.

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