Preparation method of 2-methyltetrahydrofuran and perovskite structure catalyst

Abstract

The present invention provides a method for preparing 2-methyltetrahydrofuran by gas-phase hydrogenation of 2-methylfuran and a perovskite-structured catalyst. The method includes using a perovskite-structured catalyst expressed as LaNi x M y O3 to catalyze the gas-phase hydrogenation reaction of the raw material 2-methylfuran to produce 2-methyltetrahydrofuran. The gas-phase hydrogenation reaction conditions include: a reaction pressure of 0.5 to 3.0 MPa and a reaction temperature of 80 to 150 °C; wherein, the metal promoter M in the perovskite-structured catalyst LaNi x M y O3 is selected from one of Co, Ti, Cu, Mg, Ce, Ba, Fe, Mn, and 0

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and particularly relates to a method for preparing 2-methyltetrahydrofuran by gas-phase hydrogenation of 2-methylfuran and a perovskite structure catalyst. Background Art

[0002] 2-Methyltetrahydrofuran (2-MeTHF) is an important organic synthesis intermediate and excellent organic solvent, with wide applications, including: being used as a solvent for resins, natural rubber, ethyl cellulose, and chloroacetic acid-vinyl acetate copolymer; being used for extracting aliphatic acids; being used as an initiator in the polymerization process of ethylene derivatives or butadiene; being used for preparing 1,3-pentadiene; being used as a raw material in the pharmaceutical industry for the synthesis of anti-hemorrhoid drug primaquine phosphate, etc.

[0003] Currently, there are two methods for preparing 2-methyltetrahydrofuran. The first one is specifically: using furfural as a raw material, under the catalysis of a copper-based catalyst, first undergoing a hydrogenation reaction to obtain 2-methylfuran (2-MeF), with a 2-MeF yield of 85-90%; then subjecting the obtained 2-methylfuran reaction solution to rectification and purification to obtain pure 2-methylfuran, and then in an autoclave, under the action of a nickel catalyst, at a reaction temperature of 150 °C and a reaction pressure of 15-20 MPa, hydrogenating and reducing 2-methylfuran to prepare 2-methyltetrahydrofuran. This process route is mature, the technology is stable, and large-scale production has been achieved. However, the batch autoclave hydrogenation process has low production efficiency, high labor intensity, high reaction pressure requirements, and high equipment investment. The second one is specifically: using 2-methylfuran as a raw material, directly catalyzing 2-methylfuran to undergo gas-phase hydrogenation to prepare 2-methyltetrahydrofuran by using a catalyst. This process is a continuous production and can overcome the defects of intermittent production. Currently, the 2-methyltetrahydrofuran continuous gas-phase process mainly uses noble metal catalysts. The noble metal catalyst for catalytic preparation of 2-methylfuran has a relatively high yield, which can reach 98%, but the cost of the noble metal catalyst is relatively high, which is not conducive to large-scale popularization and application. When using a Ni-based catalyst, due to the acidity on the catalyst surface, side reactions such as ring opening of 2-MeF to generate 2-pentanol occur, thereby reducing the 2-MeTHF yield, generally being 95-97%; in addition, since the hydrogenation of 2-MeF to 2-MeTHF is a strongly exothermic reaction, the catalyst is prone to deactivation due to sintering and growth of the active component Ni and carbon deposition on the catalyst surface, having the problem of short catalyst service life. Summary of the Invention

[0004] The present invention adopts an expression of LaNi x M yThe perovskite-structured catalyst of O3 catalyzes the raw material 2-methylfuran to undergo gas-phase hydrogenation reaction to produce 2-methyltetrahydrofuran, which can effectively inhibit the formation of ring-opening by-products such as 2-pentanol, improve the conversion rate of 2-methylfuran and the selectivity of 2-methyltetrahydrofuran, and at the same time has the advantage of long service life of the catalyst.

[0005] To achieve the above object, the present invention provides a method for preparing 2-methyltetrahydrofuran by gas-phase hydrogenation of 2-methylfuran. The method includes using a perovskite-structured catalyst expressed as LaNi x M y O3 to catalyze the raw material 2-methylfuran to undergo gas-phase hydrogenation reaction to produce 2-methyltetrahydrofuran. The gas-phase hydrogenation reaction conditions include: the reaction pressure is 0.5 to 3.0 MPa, and the reaction temperature is 80 to 150 °C; wherein, the metal promoter M in the perovskite-structured catalyst LaNi x M y O3 is selected from one of Co, Ti, Cu, Mg, Ce, Ba, Fe, and Mn, and 0 < x < 1, 0 < y < 1, and x + y = 1.

[0006] In a specific embodiment, the metal promoter M is selected from one of Co, Ce, and Ba, and x:y = (1.5 to 4):1.

[0007] In a specific embodiment, the perovskite-structured catalyst LaNi x M y O3 is prepared by the citric acid complex method, including the following steps:

[0008] (1) Dissolve metal precursor salts, citric acid, and ethylene glycol in deionized water to obtain a mixed solution, and stir the mixed solution at 60 to 90 °C into a sol state. The obtained sol is dried and calcined to obtain the perovskite-structured catalyst LaNi x M y O3, wherein the metal precursor salts include La salts, Ni salts, and M salts, and the molar ratio of total metal ions:citric acid:ethylene glycol = 1:(1 to 3):(0.3 to 3.5);

[0009] (2) After shaping the catalyst prepared in step (1), activate it in a reducing atmosphere.

[0010] In a specific embodiment, the drying temperature is 100 °C to 150 °C, and the drying time is 4 to 12 h; the calcination temperature is 400 to 900 °C, and the calcination time is 2 to 8 h.

[0011] In a specific embodiment, the calcination temperature is 600 to 800 °C, and the calcination time is 4 to 5 h.

[0012] In a specific embodiment, it is characterized in that the reaction pressure is 1.0 to 1.5 MPa; the reaction temperature is 110 to 130 °C.

[0013] In a specific embodiment, the gas-phase hydrogenation reaction conditions further include: the feed mass space velocity of raw material 2-methylfuran is 0.1 to 2.0 h -1 , and the molar ratio of hydrogen to 2-methylfuran is (3.0 to 20.0):1.

[0014] In a specific embodiment, the molar ratio of hydrogen to 2-methylfuran is (10 to 15):1.

[0015] The present invention also provides a perovskite structure catalyst for the gas-phase hydrogenation of 2-methylfuran to prepare 2-methyltetrahydrofuran. The expression of the perovskite structure catalyst is LaNi x M y O3, wherein the metal promoter M is selected from one of Co, Ti, Cu, Mg, Ce, Ba, Fe, Mn, and 0 < x < 1, 0 < y < 1, x + y = 1.

[0016] In a specific embodiment, the perovskite structure catalyst LaNi x M y O3 is prepared by the citric acid complex method, including the following steps:

[0017] (1) Dissolve metal precursor salts, citric acid and ethylene glycol in deionized water to obtain a mixed solution, and stir the mixed solution into a sol state at 60 to 90 °C. The obtained sol is dried and calcined to obtain the perovskite structure catalyst LaNi x M y O3, wherein the metal precursor salts include La salt, Ni salt and M salt, and the molar ratio of total metal ions: citric acid: ethylene glycol = 1:(1 to 3):(0.3 to 3.5);

[0018] (2) After shaping the catalyst prepared in step (1), activate it under a reducing atmosphere.

[0019] The beneficial effects of the present invention at least include:

[0020] First, the catalyst provided by the present invention for catalyzing the gas-phase hydrogenation reaction of 2-methylfuran to generate 2-methyltetrahydrofuran has the expression LaNi x M yThe perovskite-structured catalyst of O3, the general molecular formula of the perovskite structure is ABO3. The A site is often an alkaline earth or rare earth ion, which forms the closest cubic packing with cations. The B site is often a transition metal ion, located at the center of the octahedron. The B-site ions can be replaced by most metal ions, and the substituted metal ions are evenly dispersed and interact with each other, which helps the formation of alloys. Thus, on the one hand, the perovskite-structured catalyst LaNi x M y O3 has strong alkalinity, which can effectively inhibit the ring-opening of 2-methylfuran (2-MeF) to produce by-products such as 2-pentanol, and improve the yield of 2-methyltetrahydrofuran (2-MeTHF). On the other hand, due to the strong alkalinity on the catalyst surface, the coking of the catalyst can be greatly slowed down. At the same time, the added promoter M ions interact with the metal Ni ions, which is beneficial to the formation of alloys and inhibits the sintering of metal Ni particles. Therefore, the service life of the catalyst is extended (exceeding 2000 h).

[0021] Second, under the conditions that the reaction pressure of the method provided by the present invention is 0.5-3.0 MPa and the reaction temperature is 80-150 °C, high conversion of 2-methylfuran and high selectivity of 2-methyltetrahydrofuran can be obtained. The highest conversion of 2-methylfuran is 100%, and the highest selectivity of 2-methyltetrahydrofuran is 99.8%. Moreover, it has the advantage of a long service life of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The perovskite-structured catalyst LaNi prepared in Example 1 0.8 Ce 0.2 O3-700 °C and the catalyst life evaluation comparison chart of the prior art catalyst. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will be described in detail below with reference to the drawings and embodiments, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0024] The present invention provides a perovskite-structured catalyst for the gas-phase hydrogenation of 2-methylfuran to prepare 2-methyltetrahydrofuran. The expression of the perovskite-structured catalyst is LaNi x M y O3, wherein the metal promoter M is selected from one of Co, Ti, Cu, Mg, Ce, Ba, Fe, Mn, and 0 < x < 1, 0 < y < 1, x + y = 1.

[0025] The general molecular formula of the perovskite structure is ABO3. The A site is often an alkaline earth or rare earth ion, which forms the closest cubic packing with cations in coordination. The B site is often a transition metal ion located at the center of the octahedron. The B-site ions can be replaced by most metal ions, and the substituted metal ions are evenly dispersed and interact with each other, which helps the formation of the alloy. The perovskite structure LaNi x M y O3 catalyst has strong alkalinity, which can effectively inhibit the ring opening of 2-methylfuran (2-MeF) to form by-products such as 2-pentanol, and improve the yield of 2-methyltetrahydrofuran (2-MeTHF). In addition, due to the strong alkalinity on the catalyst surface, the coking of the catalyst can also be greatly slowed down. At the same time, due to the interaction between metal Ni ions and metal M ions, it is beneficial to form an alloy and inhibit the sintering of metal Ni particles.

[0026] Preferably, the metal promoter M is selected from one of Co, Ce, and Ba, and x:y = (1.5 - 4):1.

[0027] More preferably, the perovskite structure catalyst is LaNi 0.8 Ce 0.2 O3, LaNi 0.8 Co 0.2 O3, LaNi 0.8 Ba 0.2 O3.

[0028] Preferably, the perovskite structure catalyst LaNi x M y O3 is prepared by the citric acid complex method, including the following steps:

[0029] (1) Dissolve the metal precursor salts, citric acid, and ethylene glycol in deionized water to obtain a mixed solution, stir the mixed solution at 60 - 90 °C to form a sol state, and the obtained sol is dried and calcined to obtain the perovskite structure catalyst LaNi x M y O3, where the metal precursor salts include La salts, Ni salts, and M salts, and the molar ratio of total metal ions:citric acid:ethylene glycol = 1:(1 - 3):(0.3 - 3.5);

[0030] (2) After shaping the catalyst prepared in step (1), activate it under a reducing atmosphere.

[0031] It can be understood that the amount of substance of the total metal ions refers to the sum of the amounts of substance of La 3+ , Ni 2+ and M ions.

[0032] In this embodiment, the metal precursor salts are nitrates.

[0033] Preferably, the molar ratio of total metal ions: citric acid: ethylene glycol = 1:1:1.

[0034] Preferably, the drying temperature is 100 °C to 150 °C, and the drying time is 4 to 12 h; the calcination temperature is 400 to 900 °C, and the calcination time is 2 to 8 h; more preferably, the calcination temperature is 600 to 800 °C, and the calcination time is 4 to 5 h; more preferably, the calcination temperature is 700 °C, and the calcination time is 4 h.

[0035] Preferably, the activation step is specifically as follows: The formed catalyst is screened into 20 to 40 meshes, and loaded onto a fixed-bed reactor with an inner diameter of 8 mm for activation. The activation conditions include: the gas hourly space velocity is 600 h -1 , the reduction temperature is 550 °C, the hydrogen pressure is atmospheric pressure, and the reduction time is 6 h.

[0036] The present invention also provides a method for preparing 2-methyltetrahydrofuran by gas-phase hydrogenation of 2-methylfuran. The method includes using a perovskite-structured catalyst with the formula LaNi x M y O3 to catalyze the gas-phase hydrogenation reaction of the raw material 2-methylfuran to produce 2-methyltetrahydrofuran. The gas-phase hydrogenation reaction conditions include: the reaction pressure is 0.5 to 3.0 MPa, and the reaction temperature is 80 to 150 °C; wherein, the metal promoter M in the perovskite-structured catalyst LaNi x M y O3 is selected from one of Co, Ti, Cu, Mg, Ce, Ba, Fe, and Mn, and 0 < x < 1, 0 < y < 1, x + y = 1.

[0037] The general molecular formula of the perovskite structure is ABO3. The A site is often an alkaline earth or rare earth ion, which forms the closest cubic packing with cations in coordination; the B site is often a transition metal ion, located at the center of the octahedron. The B-site ions can be replaced by most metal ions, and the substituted metal ions are evenly dispersed and interact with each other, which helps the formation of the alloy. The perovskite-structured catalyst LaNi x M y O3 has strong alkalinity, which can effectively inhibit the ring-opening of 2-methylfuran (2-MeF) to form by-products such as 2-pentanol, and improve the yield of 2-methyltetrahydrofuran (2-MeTHF). In addition, due to the strong alkalinity on the catalyst surface, the coking of the catalyst can be greatly slowed down. At the same time, due to the interaction between metal Ni ions and metal M ions, it is beneficial to form an alloy and inhibit the sintering of metal Ni particles.

[0038] Preferably, the metal promoter M is selected from one of Co, Ce, and Ba, and x:y = (1.5 to 4):1.

[0039] Preferably, the perovskite structure catalyst is LaNi 0.8 Ce 0.2 O3, LaNi 0.8 Co 0.2 O3, LaNi 0.8 Ba 0.2 O3.

[0040] Preferably, the perovskite structure catalyst LaNi x M y O3 is prepared by the citric acid complex method, including the following steps:

[0041] (1) Dissolve the metal precursor salts, citric acid and ethylene glycol in deionized water to obtain a mixed solution, and stir the mixed solution at 60-90 °C into a sol state. The obtained sol is dried and calcined to obtain the perovskite structure catalyst LaNi x M y O3, where the metal precursor salts include La salts, Ni salts and M salts, and the molar ratio of total metal ions: citric acid: ethylene glycol = 1: (1-3): (0.3-3.5);

[0042] (2) After shaping the catalyst prepared in step (1), activate it under a reducing atmosphere.

[0043] In this embodiment, the metal precursor salt is nitrate.

[0044] Preferably, the molar ratio of total metal ions: citric acid: ethylene glycol = 1: 1: 1.

[0045] Preferably, the drying temperature is 100 °C - 150 °C, and the drying time is 4 - 12 h; the calcination temperature is 400 - 900 °C, and the calcination time is 2 - 8 h; more preferably, the calcination temperature is 600 - 800 °C, and the calcination time is 4 - 5 h. More preferably, the calcination temperature is 700 °C, and the calcination time is 4 h.

[0046] Preferably, the activation step is specifically: screen the shaped catalyst into 20 - 40 meshes, load it onto a fixed bed reactor with an inner diameter of 8 mm for activation. The activation conditions include: the gas hourly space velocity is 600 h -1 , the reduction temperature is 550 °C, the hydrogen pressure is atmospheric pressure, and the reduction time is 6 h.

[0047] Preferably, the reaction pressure is 1.0 - 1.5 MPa; the reaction temperature is 110 - 130 °C.

[0048] Preferably, the gas phase hydrogenation reaction conditions further include: the feed mass hourly space velocity of raw material 2-methylfuran is 0.1 - 2.0 h -1and the molar ratio of hydrogen to 2-methylfuran is (3.0 to 20.0):1, more preferably, the molar ratio of hydrogen to 2-methylfuran is (10 to 15):1.

[0049] Example 1

[0050] Catalyst preparation:

[0051] Weigh a certain mass of lanthanum nitrate hexahydrate, nickel nitrate hexahydrate, and cerium nitrate hexahydrate according to the molar ratio of total metal ions: citric acid: ethylene glycol = 1:1:1, and dissolve them in purified water. Among them, the molar ratio of La:Ni:Ce in the total metal ions = 1:0.8:0.2. The above mixed solution is stirred into a sol state at 80 °C, dried at 120 °C for 4 h, and calcined at 700 °C for 4 h to obtain Catalyst 1, that is, the perovskite structure catalyst LaNi 0.8 Ce 0.2 O3 - 700 °C.

[0052] Catalyst evaluation: The above catalyst is formed and sieved into 20 - 40 meshes, weigh 1.0 g, and load it onto a fixed-bed reactor with an inner diameter of 8 mm. The gas hourly space velocity is 600 h-1, the reduction temperature is 550 °C, the hydrogen pressure is atmospheric pressure, and the reduction is carried out for 6 h. After the reduction is completed, the system back pressure is adjusted to 1.0 MPa, the reaction temperature is 110 °C, the molar ratio of hydrogen to 2-MeF is 10.0, and the mass hourly space velocity of 2-MeF feed is 0.8 h -1 , and the evaluation results are shown in Table 1.

[0053] Example 2

[0054] Same as Example 1, except that the metal promoter M added in the catalyst preparation step is different. In Example 1, the metal promoter M is Ce, and in Example 2, the metal promoter is Co, that is, LaNi 0.8 Co 0.2 O3.

[0055] Example 3

[0056] Same as Example 1, except that the metal promoter M added in the catalyst preparation step is different. In Example 1, the metal promoter M is Ce, and in Example 3, the metal promoter is Ba, that is, LaNi 0.8 Ba 0.2 O3.

[0057] Example 4

[0058] Same as Example 1, except that the amount of the metal promoter M added in the catalyst preparation step is different. In Example 1, the molar ratio of La:Ni:Ce in the total metal ions = 1:0.8:0.2, and in Example 4, the molar ratio of La:Ni:Ce in the total metal ions = 1:1:0, that is, LaNiO3.

[0059] Example 5

[0060] Same as Example 1, except that the amount of metal promoter M added in the catalyst preparation step is different. In Example 1, the molar ratio of La:Ni:Ce in the total metal ions is 1:0.8:0.2, and in Example 4, the molar ratio of La:Ni:Ce in the total metal ions is 1:0.6:0.4, that is, LaNi 0.6 Ce 0.4 O3.

[0061] Example 6

[0062] Same as Example 1, except that the calcination temperature in the catalyst preparation step is different. The calcination temperature of the catalyst in Example 1 is 700 °C, and the calcination temperature of the catalyst in Example 6 is 600 °C, that is, LaNi 0.8 Ce 0.2 O3 - 600 °C.

[0063] Example 7

[0064] Same as Example 1, except that the calcination temperature in the catalyst preparation step is different. The calcination temperature of the catalyst in Example 1 is 700 °C, and the calcination temperature of the catalyst in Example 7 is 800 °C, that is, LaNi 0.8 Ce 0.2 O3 - 800 °C.

[0065] Example 8

[0066] Preparation of catalyst: Using γ-Al2O3 as the carrier, impregnating with nickel nitrate solution by equal-volume impregnation, drying at 120 °C for 4 h, and calcining at 700 °C for 4 h. The loading amount of Ni is 30%, and catalyst 30% Ni / γ-A l2 O3.

[0067] Table 1 Performance evaluation of different catalysts for gas-phase hydrogenation of 2-methylfuran to 2-methyltetrahydrofuran

[0068]

[0069] As can be seen from Table 1, using LaNi 0.8 M 0.2 O3 with a perovskite structure as the catalyst can significantly inhibit the ring-opening by-products, improve the selectivity of 2-methyltetrahydrofuran. And due to the perovskite structure and the action of metal promoter M, the dispersion of metal Ni is high, and the conversion rate of 2-methylfuran is significantly improved; at the same time, choosing metal Ce as the promoter, the selectivity of 2-methyltetrahydrofuran is the highest.

[0070] Comparing the result data of Examples 1 to 4 shows that the presence of additive M improves the dispersion of Ni, thereby increasing the conversion rate of 2-methylfuran. Comparing the result data of Examples 1, 4, and 5 shows that there is an optimal value for the addition amount of additive Ce. Without addition, the particle size of the prepared catalyst metal Ni is large and the catalyst activity is poor. If the addition amount is too large, the loading amount of metal Ni decreases, which will also cause a decrease in catalyst activity. Comparing the result data of Examples 1, 6, and 7 shows that the calcination temperature affects the performance of the catalyst, and the catalyst calcination temperature of 700 °C is more appropriate.

[0071] Examples 9 to 19

[0072] Examples 9 to 19 all use the catalyst LaNi prepared in Example 1 0.8 Ce 0.2 O3 - 700 °C. The main difference lies in the catalyst evaluation step, and the gas-phase hydrogenation reaction conditions for the gas-phase hydrogenation of 2-methylfuran to 2-methyltetrahydrofuran are different. The gas-phase hydrogenation reaction conditions in Example 1 are: the reaction pressure is 1.0 MPa, the reaction temperature is 110 °C, the feed mass space velocity is 0.8 h -1 , and the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 9 are that the reaction pressure is 1.0 MPa, the reaction temperature is 90 °C, the feed mass space velocity is 0.8 h -1 , and the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 10 are that the reaction pressure is 1.0 MPa, the reaction temperature is 100 °C, the feed mass space velocity is 0.8 h -1 , and the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 11 are that the reaction pressure is 1.0 MPa, the reaction temperature is 120 °C, the feed mass space velocity is 0.8 h -1 , and the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 12 are that the reaction pressure is 1.0 MPa, the reaction temperature is 130 °C, the feed mass space velocity is 0.8 h -1 , and the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 13 are that the reaction pressure is 0.1 MPa, the reaction temperature is 110 °C, the feed mass space velocity is 0.8 h -1 , and the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 14 are that the reaction pressure is 0.5 MPa, the reaction temperature is 110 °C, the feed mass space velocity is 0.8 h -1 , and the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 15 are that the reaction pressure is 1.5 MPa, the reaction temperature is 110 °C, the feed mass space velocity is 0.8 h -1, the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 16 are a reaction pressure of 1.0 MPa, a reaction temperature of 110 °C, and a feed mass space velocity of 0.5 h -1 , the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 17 are a reaction pressure of 1.0 MPa, a reaction temperature of 110 °C, and a feed mass space velocity of 1.0 h -1 , the molar ratio of hydrogen to 2-methylfuran is 10:1; the gas-phase hydrogenation reaction conditions in Example 18 are a reaction pressure of 1.0 MPa, a reaction temperature of 110 °C, and a feed mass space velocity of 1.0 h -1 , the molar ratio of hydrogen to 2-methylfuran is 5:1; the gas-phase hydrogenation reaction conditions in Example 19 are a reaction pressure of 1.0 MPa, a reaction temperature of 110 °C, and a feed mass space velocity of 1.0 h -1 , the molar ratio of hydrogen to 2-methylfuran is 15:1. The catalyst evaluation results of each example are shown in Table 2.

[0073] Table 2 Influence of reaction conditions on the performance of gas-phase hydrogenation of 2-methylfuran to 2-methyltetrahydrofuran

[0074]

[0075]

[0076] Table 2 shows the influence of gas-phase hydrogenation reaction conditions on the performance of gas-phase hydrogenation of 2-methylfuran to 2-methyltetrahydrofuran. Comparing the result data of Example 1 and Examples 9 to 12, it can be seen that when other gas-phase hydrogenation reaction conditions are the same, as the reaction temperature increases from 90 °C to 110 °C, the conversion rate of 2-methylfuran gradually increases. Further increasing the reaction temperature, the selectivity of 2-methyltetrahydrofuran decreases. Therefore, the reaction temperature is more preferably 110 °C.

[0077] Comparing the result data of Example 1 and Examples 13 to 15, it can be seen that when other gas-phase hydrogenation reaction conditions are the same, the reaction pressure has a greater influence on the gas-phase hydrogenation of 2-methylfuran. Under atmospheric pressure, the conversion rate of 2-methylfuran is only 35.6%. As the pressure increases, the conversion rate of 2-methylfuran gradually increases. At a reaction pressure of 1.0 MPa, 2-methylfuran is almost completely converted. Further increasing the pressure has no effect on the conversion rate and selectivity. Therefore, the reaction pressure is more preferably 1.0 MPa.

[0078] Comparing the result data of Example 1 and Examples 16 to 17, it can be seen that when the feed mass space velocity of 2-methylfuran is 0.8 h -1 , 2-methylfuran is almost completely converted. Further increasing the mass space velocity of 2-methylfuran to 1.0 h -1When the space velocity is [value not provided], the conversion rate of 2-methylfuran decreases to 97.8%, and it can no longer be completely converted. Therefore, the mass hourly space velocity of 2-methylfuran feed is preferably 0.1 - 0.8 h -1 .

[0079] Comparing the result data of Example 1 and Examples 18 to 19, it can be seen that when the H2 / 2-MeF molar ratio is 5.0, the conversion rate of 2-methylfuran is only 96.9%. When the H2 / 2-MeF molar ratio increases to 10.0, 2-methylfuran is close to complete conversion. Further increasing the H2 / 2-MeF molar ratio to 15.0, the selectivity of 2-methyltetrahydrofuran slightly decreases. Therefore, the H2 / 2-MeF molar ratio is more preferably 10.0.

[0080] Example 20

[0081] Under the reaction conditions of a reaction temperature of 110 °C, a mass hourly space velocity of 2-methylfuran feed of 0.5 h-1, an H2 / 2-MeF molar ratio of 10.0, and a pressure of 1.0 MPa, catalyst 1 (LaNi 0.8 Ce 0.2 O3 - 700 °C) was subjected to a long-term stability test. The liquid-phase products at the outlet of the gas-phase hydrogenation reactor were collected for analysis, and the analysis results are shown in Figure 1 .

[0082] The results of the periodic stability test of the catalyst were compared with the stability test results of the catalysts involved in the prior art and plotted into a graph. From Figure 1 it can be seen that catalyst 1 has good stability. After the catalyst has been continuously used for 2000 h, the conversion rate of 2-MeF still remains above 99.5%, and the selectivity of 2-MeTHF is as high as above 99.5%. The special perovskite structure and the introduction of Ce play a role in separating Ni particles and prolonging the catalyst life. For ordinary Ni / γ-Al2O3 catalysts, after reacting for 250 h, the residual amount of 2-MeF reaches 25%, and the selectivity of 2-MeTHF is only 88%.

[0083] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions and substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for the gas-phase hydrogenation of 2-methylfuran to prepare 2-methyltetrahydrofuran, characterized in that, The method includes using a perovskite structure catalyst with the formula LaNi x M y O3 to catalyze the gas-phase hydrogenation reaction of the raw material 2-methylfuran to produce 2-methyltetrahydrofuran. The gas-phase hydrogenation reaction conditions include: the reaction pressure is 1.0 - 1.5 MPa, and the reaction temperature is 110 - 130 °C; in the perovskite structure catalyst LaNi x M y O3, the metal promoter M is selected from one of Co, Ce, and Ba, 0 < x < 1, 0 < y < 1, x + y = 1, and x:y = (1.5 - 4):

1. Among them, the perovskite structure catalyst LaNi x M y O3 is prepared by the citric acid complex method, including the following steps: (1) Dissolve a metal precursor salt, citric acid, and ethylene glycol in deionized water to obtain a mixed solution, and stir the mixed solution at 60-90 °C to form a sol state. The obtained sol is dried and calcined to obtain the perovskite structure catalyst LaNi x M y O3, wherein the metal precursor salt includes La salt, Ni salt, and M salt, and the molar ratio of total metal ions: citric acid: ethylene glycol = 1: (1-3): (0.3-3.5); (2) After the catalyst prepared in step (1) is formed, it is activated under a reducing atmosphere.

2. The method for preparing 2-methyltetrahydrofuran by gas-phase hydrogenation of 2-methylfuran according to claim 1, characterized in that, The drying temperature is 100°C to 150°C, and the drying time is 4 to 12 h; the calcination temperature is 400 to 900°C, and the calcination time is 2 to 8 h.

3. The method for preparing 2-methyltetrahydrofuran by gas-phase hydrogenation of 2-methylfuran according to claim 2, wherein The calcination temperature is 600 to 800°C, and the calcination time is 4 to 5 h.

4. The method for preparing 2-methyltetrahydrofuran by gas-phase hydrogenation of 2-methylfuran according to claim 1, characterized in that, The gas-phase hydrogenation reaction conditions further include: the feed mass space velocity of the raw material 2-methylfuran is 0.1~2.0 h -1 , and the molar ratio of hydrogen to 2-methylfuran is (3.0~20.0):

1.

5. The method for preparing 2-methyltetrahydrofuran by gas-phase hydrogenation of 2-methylfuran according to claim 4, characterized in that, The molar ratio of hydrogen to 2-methylfuran is (10 to 15):1.

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