A catalyst and a method for preparing 2,5-tetrahydrofuran dimethyl alcohol in aqueous phase using the catalyst

Abstract

The application discloses a kind of high activity catalyst and utilize the catalyst in aqueous phase 5-hydroxymethylfurfural one-step hydrogenation preparation 2,5-tetrahydrofuran dimethyl alcohol method.The catalyst described in the application directly introduces nickel salt into furfuryl alcohol urea formaldehyde resin, then the obtained resin is calcined under hydrogen atmosphere to obtain metallic nickel-based catalyst, because the catalyst has excellent affinity with HMF, HMF can be selectively prepared THFDM under relatively mild reaction conditions in aqueous phase, and the yield of THFDM is up to 93%.The catalyst preparation process of the application is simple, the hydrogenation reaction condition is mild, the yield of THFDM is high, and HMF crude product aqueous solution can be used as substrate, and it has good industrial application prospect.In addition, HMF has good water solubility, considering the principles of green and sustainable chemistry, water is used as reaction medium, compared with expensive organic solvent, the post-processing cost can be greatly reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalysts and organic synthesis, and particularly relates to a catalyst and a method for preparing 2,5-tetrahydrofurfurandimethanol by one-step hydrogenation of 5-hydroxymethylfurfural in an aqueous phase by using the catalyst. BACKGROUND

[0002] 5-hydroxymethylfurfural (HMF) is listed by the US Department of Energy as one of the top ten bio-based chemicals, which can be used as a platform compound to prepare a series of derivatives for various fields such as energy, chemical industry, agriculture, and medicine. Tetrahydrofurfurandimethanol (THFDM) is a thermally stable diol, which can be used as a monomer for the preparation of polyester compounds, fuel additives, coating additives, and can also be used for the synthesis of 1,6-hexanediol, 1,5-hexanediol, 1,2,6-hexanetriol and other high-value compound monomers.

[0003] HMF selective preparation of THFDM is generally carried out in an organic solvent and mainly uses a noble metal catalyst. There are few reports on the high-selectivity preparation of THFDM from HMF in pure aqueous phase. For example, Nakagawa and Tomishige used Pd-Ni / SiO2 catalyst to achieve 96% THFDM yield in pure aqueous phase at 40℃ and 80 bar hydrogen atmosphere (Catalysis Communications, 2010, 12(3), 154-156); when Pd-Ir / SiO2 is used as the catalyst, the THFDM yield reaches 95% under the optimal conditions (ACS Catal 2014;4:2718-26); Chen et al. synthesized Pd / MIL-101(Al)-NH2 catalyst, and achieved 96% high yield of THFDM in water as solvent at near room temperature (30℃) and mild pressure (10 bar). The above all use noble metal catalysts. In the noble metal catalytic system, high-selectivity conversion of HMF can be achieved under relatively mild H2 conditions. However, due to the low reserves and high price of noble metals, and the fact that the supply is greatly affected by market fluctuations, the development and practical industrial application of noble metal catalysts are limited. In addition, under relatively harsh conditions, non-noble metal catalyst systems can also achieve high-efficiency conversion of HMF, and obtain high yield comparable to noble metal catalysts. However, under relatively harsh conditions, HMF is prone to hydrogenolysis, ring-opening, polymerization and other side reactions, which brings great challenges to obtaining THFDM with high yield and selectivity.

[0004] Currently, it is still a challenging research direction to catalyze HMF to prepare THFDM with high selectivity under mild reaction conditions in pure water phase by using non-noble metal. Patent CN 113773284A discloses a method for catalyzing HMF to prepare THFDM in water phase by using Ni-Co / SiO2, and the THFDM yield reaches 83% under the conditions of 110 ℃ and 30 bar hydrogen pressure; however, the reaction temperature is relatively high, and a bimetallic catalyst is used, so the preparation process is complex, and in addition, the yield is low. Therefore, it is of important practical significance to develop a non-noble metal catalyst and catalyze HMF to prepare THFDM with high selectivity under mild reaction conditions in pure water phase. SUMMARY

[0005] In view of the above problems, the present application provides a catalyst and a method for preparing 2,5-tetrahydrofurfurandimethanol in water phase by using the catalyst, and the main technical problem to be solved is that the selective hydrogenation of 5-hydroxymethylfurfural to prepare THFDM is generally carried out in an organic solvent, and the reaction conditions are harsh and the selectivity is low when a non-noble metal catalyst is used. In order to solve the technical problem, the present application uses furfuryl alcohol urea formaldehyde resin as a carrier, and the similar furan carrier structure and the introduction of nitrogen element in the urea formaldehyde resin enhance the adsorption of the substrate HMF and the active sites of the catalyst in water phase, so that the HMF is prepared with high selectivity in water phase, and the THFDM yield is > 90% under relatively mild hydrogenation conditions.

[0006] In order to achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0007] A high-activity catalyst is prepared by the following process: dissolving a nickel salt in a formaldehyde solution, adding urea and stirring for 0.5-2 h, then adding a certain amount of furfuryl alcohol and continuing to stir, and then heating to 90-150 ℃ for polymerization reaction for 6-24 h to obtain a furfuryl alcohol urea formaldehyde resin material containing nickel ion precursor Ni-UFF, and then calcining the obtained furfuryl alcohol urea formaldehyde resin material Ni-UFF in H2 / Ar mixed gas at a certain temperature for 4-12 h to obtain the catalyst Ni-UFFC.

[0008] Further, in the process, the molar ratio of formaldehyde to urea is 0.5-2:1; and the molar ratio of nickel salt to urea is 0.01-0.1:1.

[0009] Further, in the process, the mass ratio of furfuryl alcohol to urea is 0.1-3:1.

[0010] Further, in the process, the calcination temperature of the furfuryl alcohol urea formaldehyde resin material Ni-UFF is 300-700 ℃, and the H2 content in the H2 / Ar mixed gas is 10%.

[0011] The application further provides a method for preparing 2,5-tetrahydrofurfurandimethanol in an aqueous phase by using the catalyst, comprising the following steps: adding 5-hydroxymethylfurfural, deionized water and the catalyst in a certain proportion into a high-pressure reaction kettle, replacing the air in the reaction kettle with hydrogen, then filling H2, the pressure of H2 is 5-40 bar, placing the high-pressure reaction kettle in a constant-temperature water bath to perform reaction, cooling to room temperature after reaching the reaction time, discharging the residual hydrogen, filtering the reaction liquid, and collecting the filtrate to obtain the product.

[0012] Further, in the process, the adding amount ratio of 5-hydroxymethylfurfural, deionized water and the catalyst is 5-50 mmol: 10-20 g: 50-200 mg.

[0013] Further, the temperature of the constant-temperature water bath is 30-80 DEG C, and the reaction time is 1-12 h.

[0014] Further, the collected filtrate is diluted with water, and the yield of 2,5-tetrahydrofurfurandimethanol is detected by using high performance liquid chromatography differential method.

[0015] The application has the following beneficial effects:

[0016] The application directly introduces the nickel salt into the furfuryl alcohol urea formaldehyde resin, then calcines the obtained resin under a hydrogen atmosphere to obtain a metallic nickel-based catalyst, the catalyst has excellent affinity with HMF, the HMF can be selectively prepared into THFDM under relatively mild reaction conditions, and the yield of THFDM is up to 93%. The catalyst is very simple to prepare, the hydrogenation reaction condition is mild, the yield of THFDM is high, and the HMF crude aqueous solution can be used as a substrate, so the application has good industrial application prospect. In addition, HMF has good water solubility, and the principle of green and sustainable chemistry is considered, water is used as a reaction medium, compared with expensive organic solvents, the post-processing cost can be greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a liquid phase differential chromatogram of the reaction liquid of the embodiment 1 of the application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the application more clear, the technical scheme of the application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0019] Embodiment 1

[0020] 1. Catalyst preparation:

[0021] A solution of 0.64 g Ni(NO3)2·6H2O in 4.1 g 37% formaldehyde solution was prepared. 3 g urea was added and stirred for 1 h, then 3 g furfuryl alcohol was added. After stirring for 1 h, the solution was heated to 100 °C and polymerized for 12 h to obtain a furfuryl alcohol formaldehyde resin material containing nickel ion precursor (Ni-UFF). The obtained Ni-UFF material was calcined at 500 °C for 4 h in a 10% H2 / Ar mixed gas to obtain a Ni / UFFC-500 catalyst, which was stored in a nitrogen atmosphere for standby.

[0022] 2. Preparation of THFDM in aqueous phase (catalyst performance evaluation):

[0023] A 50 mL high-pressure reactor was charged with 1.26 g HMF, 15 g water, and 50 mg Ni / UFFC-500 catalyst. After replacing the air in the reactor with hydrogen three times, 20 bar of H2 was charged. The reactor was placed in a 40 °C constant temperature water bath and reacted for 5 h. After reaching the reaction time, the reactor was cooled to room temperature, the remaining hydrogen was released, the reaction solution was filtered, the filtrate was diluted with water to 25 mL, and the THFDM yield was determined by high performance liquid chromatography differential method (as shown in Figure 1 ).

[0024] The conversion of raw materials and the yield of product THFDM were determined by liquid chromatography external standard method, and the average value of three tests was taken.

[0025] The conversion of HMF and the yield of product THFDM were calculated according to the following formula:

[0026] Formula 1: Conversion [mol%] = (n0-n) / n0 x 100%;

[0027] Formula 2: Yield [mol%] = n i / n0 x 100%.

[0028] In the formula, n0 is the initial molar amount of HMF [mol];

[0029] n is the residual molar amount of HMF after reaction [mol];

[0030] n i is the molar amount of product THFDM generated after reaction [mol].

[0031] The calculation results show that the HMF conversion after reaction is 98%, and the product THFDM yield is 90%.

[0032] Example 2-6

[0033] In other embodiments of the present application, in order to verify the influence of catalyst calcination temperature on catalyst activity, the reaction conditions of Example 1 were adjusted: except that the catalyst was different, the other reaction conditions were the same as those of Example 1. The reaction results are shown in Table 1 below.

[0034] Example Catalyst HMF conversion THFDM yield Example 2 Ni / UFFC-300 83％ 74％ Example 3 Ni / UFFC-400 96％ 87％ Example 4 Ni / UFFC-400a >99％ 92％ Example 5 Ni / UFFC-600 99％ 86％ Example 6 Ni / UFFC-700 95％ 79％

[0035] a indicates that the calcination time is extended to 12 h;

[0036] As can be seen from the above table, with the increase of the calcination temperature, the activity of the obtained Ni / UFFC catalyst shows a trend of first increasing and then decreasing. A lower calcination temperature leads to the fact that the high-valence nickel ions cannot be completely reduced to the metallic state, and thus the activity is lower. When the catalyst is calcined at 300°C, the HMF conversion rate is 83%, and the THFDM yield is 74%. With the increase of the calcination temperature, the HMF conversion rate and the THFDM yield increase significantly. When the calcination temperature is 400°C, the THFDM yield is 87%. When the calcination time is further extended to 12 h, after the nickel ions are sufficiently reduced, the activity of the catalyst is further improved, the HMF conversion rate is >99%, and the THFDM yield reaches 92%. However, with the further increase of the calcination temperature, the HMF conversion rate and the THFDM yield gradually decrease, which is presumably due to the fact that the aggregation of the metallic nickel particles leads to the decrease of the activity.

[0037] Examples 7-9

[0038] In other embodiments of the present application, in order to verify the influence of the introduction of urea on the activity of the catalyst, the conditions for preparing the catalyst in Example 1 were adjusted: except that the amount of urea introduced was different, the other conditions were the same as those of Example 1. The reaction results are shown in Table 2 below.

[0039] Example Urea introduction amount / g HMF conversion THFDM yield Example 7 0 49％ 32％ Example 8 0.75 75％ 63％ Example 9 1.5 97％ 87％

[0040] As can be seen from Table 2, as a blank comparison, in the absence of the introduction of urea, the catalyst activity is very low, the HMF conversion rate is only 49%, and the THFDM yield is 32%, and the main by-product is furan dimethyl alcohol. With the increase of the amount of urea introduced, the catalyst activity increases obviously. When the amount of urea introduced is equal to that of formaldehyde (Example 9), the catalyst selectivity is equivalent to that of Example 1. Transmission electron microscopy analysis shows that the introduction of nitrogen element is beneficial to the dispersion of the nickel metal and the stability during the calcination process, which is also the reason why the activity is relatively high.

[0041] Examples 10-15

[0042] In other embodiments of the present application, in order to examine the influence of the catalytic reaction conditions on the THFDM yield, the reaction conditions of Example 1 were adjusted: except that the reaction conditions were different, the other conditions were the same as those of Example 1. The reaction results are shown in Table 3 below.

[0043]

[0044] As shown in Table 3, when the hydrogen pressure is too low, the reaction proceeds relatively slowly, and the main by-product is the intermediate 2,5-furan dimethanol, even if the reaction temperature is increased and the reaction time is extended, the selectivity of THFDM is still low (Examples 10-13); when the hydrogen pressure is increased to 30 bar, the HMF is essentially completely converted after 3 h, and the yield of THFDM is comparable to that obtained after 5 h at 20 bar (Example 14 vs. Example 1); when the hydrogen pressure is further increased to 40 bar, the yield of THFDM reaches a maximum value of 93% after 1 h at 30°C, which shows that a relatively low reaction temperature and a high hydrogen pressure are helpful to improve the selectivity of THFDM.

[0045] Example 16

[0046] 3 g of fructose was dissolved in 20 mL of deionized water, 1 g of HND-587 super strong solid acid catalyst was added, and the temperature was increased to 120°C in a 50 mL reactor for 1 h. After the reaction was completed, the temperature was cooled to room temperature, the catalyst was removed by filtration, and the filtrate was used to determine the yield of HMF, which was 61%. The filtrate was used as the crude HMF, 50 mg of Ni / UFFC-500 catalyst was added to a 50 mL high-pressure reactor, the reactor was filled with 40 bar of H2 after the air in the reactor was replaced with hydrogen three times, and the reactor was placed in a 30°C constant temperature water bath for 1 h. After the reaction time was reached, the temperature was cooled to room temperature, the remaining hydrogen was removed, the reaction liquid was filtered, the filtrate was diluted with water to 25 mL, and the yield of THFDM was determined by high performance liquid chromatography. The results show that the conversion rate of HMF after the reaction is 87%, and the yield of the product THFDM is 77%. This example shows that when the crude HMF is used as the substrate, the catalyst still has excellent catalytic selectivity, but the presence of impurities affects the activity of the catalyst, resulting in a relatively slow reaction.

[0047] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A catalyst for catalyzing the production of 2,5-tetrahydrofuran dimethylol from 5-hydroxymethylfurfural in an aqueous phase, characterized in that, The catalyst is prepared by the following process: dissolving a nickel salt in a formaldehyde solution, adding urea and stirring, then adding a certain amount of furfuryl alcohol and continuing to stir, and then heating to a predetermined temperature for polymerization to obtain a furfuryl alcohol urea formaldehyde resin material containing a nickel ion precursor Ni-UFF, and calcining the obtained furfuryl alcohol urea formaldehyde resin material Ni-UFF in H2 / Ar mixed gas at a certain temperature to obtain the catalyst Ni-UFFC.

2. The catalyst according to claim 1, characterized in that, In the process, the molar ratio of formaldehyde to urea is 0.5-2:1, and the molar ratio of nickel salt to urea is 0.01-0.1:

1.

3. The catalyst of claim 2, wherein In the process, the mass ratio of furfuryl alcohol to urea is 0.1-3:

1.

4. The catalyst of claim 3, wherein The process is as follows: dissolving a nickel salt in a formaldehyde solution, adding urea and stirring for 0.5-2h, then adding a certain amount of furfuryl alcohol and continuing to stir, and then heating to 90-150℃ for polymerization for 6-24h to obtain a furfuryl alcohol urea formaldehyde resin material containing a nickel ion precursor Ni-UFF, and calcining the obtained furfuryl alcohol urea formaldehyde resin material Ni-UFF in H2 / Ar mixed gas at a temperature of 300-700℃ for 4-12h to obtain the catalyst Ni-UFFC, wherein the H2 / Ar mixed gas contains 10% H2.

5. Process for the preparation of 2,5-tetrahydrofuran dimethylol in aqueous phase using the catalyst according to any one of claims 1 to 4, characterized in that, The process comprises the following steps: adding a certain proportion of 5-hydroxymethylfurfural, deionized water and the catalyst into a high-pressure reaction kettle, replacing the air in the reaction kettle with hydrogen, and then filling H2 to a pressure of 5-40bar, placing the high-pressure reaction kettle in a constant-temperature water bath for reaction, cooling to room temperature after the reaction time is reached, discharging the remaining hydrogen, filtering the reaction liquid, and collecting the filtrate to obtain the product.

6. The method of claim 5, wherein, In the process, the addition amount ratio of 5-hydroxymethylfurfural, deionized water and the catalyst is 5-50mmol:10-20g:50-200mg.

7. The method of claim 5, wherein, The constant-temperature water bath temperature is 30-80℃, and the reaction time is 1-12h.

8. The method of claim 5, wherein, The collected filtrate is diluted with water, and the yield of 2,5-tetrahydrofuran dimethyl alcohol is detected by high-performance liquid chromatography differential method. The catalyst is prepared by the following process: dissolving a nickel salt in a formaldehyde solution, adding urea and stirring, then adding a certain amount of furfuryl alcohol and continuing to stir, and then heating to a predetermined temperature for polymerization to obtain a furfuryl alcohol urea formaldehyde resin material containing a nickel ion precursor Ni-UFF, and calcining the obtained furfuryl alcohol urea formaldehyde resin material Ni-UFF in H2 / Ar mixed gas at a certain temperature to obtain the catalyst Ni-UFFC. In the process, the molar ratio of formaldehyde to urea is 0.5-2:1, and the molar ratio of nickel salt to urea is 0.01-0.1:

1. In the process, the mass ratio of furfuryl alcohol to urea is 0.1-3:

1. The process is as follows: dissolving a nickel salt in a formaldehyde solution, adding urea and stirring for 0.5-2h, then adding a certain amount of furfuryl alcohol and continuing to stir, and then heating to 90-150℃ for polymerization for 6-24h to obtain a furfuryl alcohol urea formaldehyde resin material containing a nickel ion precursor Ni-UFF, and calcining the obtained furfuryl alcohol urea formaldehyde resin material Ni-UFF in H2 / Ar mixed gas at a temperature of 300-700℃ for 4-12h to obtain the catalyst Ni-UFFC, wherein the H2 / Ar mixed gas contains 10% H2. The process comprises the following steps: adding a certain proportion of 5-hydroxymethylfurfural, deionized water and the catalyst into a high-pressure reaction kettle, replacing the air in the reaction kettle with hydrogen, and then filling H2 to a pressure of 5-40bar, placing the high-pressure reaction kettle in a constant-temperature water bath for reaction, cooling to room temperature after the reaction time is reached, discharging the remaining hydrogen, filtering the reaction liquid, and collecting the filtrate to obtain the product. In the process, the addition amount ratio of 5-hydroxymethylfurfural, deionized water and the catalyst is 5-50mmol:10-20g:50-200mg. The constant-temperature water bath temperature is 30-80℃, and the reaction time is 1-12h. The collected filtrate is diluted with water, and the yield of 2,5-tetrahydrofuran dimethyl alcohol is detected by high-performance liquid chromatography differential method.

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