Method for continuous preparation of methylglyoxal based on gas phase oxidation of glycerol

Abstract

The application relates to a method for continuously preparing methylglyoxal based on a glycerol gas-phase oxidation reaction, which comprises the following steps: subjecting pure glycerol or a glycerol solution to vaporization treatment to form raw material vapor; mixing the raw material vapor with O2-containing gas to form mixed gas; and contacting the mixed gas with a supported nanometer gold catalyst to generate selective oxidation reaction to form methylglyoxal, wherein the carrier of the supported nanometer gold catalyst is a metal oxide.

Description

Technical Field

[0001] This application relates to the field of biomass resource catalytic conversion and utilization technology, and in particular to a method for the continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction. Background Technology

[0002] Acetone aldehyde is an important organic chemical intermediate, mainly used in the synthesis of the stomach medicine cimetidine and the flavor enhancer furanone. It can also be used to synthesize drugs with analgesic, anticancer, antihypertensive, bactericidal and antiviral effects, as well as chemicals such as pesticides, antioxidants, and fiber treatment agents. Therefore, it has a wide range of applications in the fields of medicine, food, cosmetics, pesticides, rubber, and textiles.

[0003] Industrially, acetone aldehyde is often produced using 1,2-propanediol as a raw material and electrolytic silver as a catalyst, as illustrated in domestic patent CN1240203A. Because electrolytic silver has low activity at low temperatures, the reaction must be carried out at relatively high temperatures (450℃~650℃). At high temperatures, the catalyst is more prone to deactivation due to sintering. Furthermore, 1,2-propanediol is derived from propylene, making acetone aldehyde production heavily reliant on non-renewable fossil fuels. As fossil fuel reserves dwindle, the production cost of acetone aldehyde will gradually increase. Summary of the Invention

[0004] Given the above background, it is necessary to provide a continuous method for the preparation of acetone aldehyde based on biomass conversion and glycerol gas-phase oxidation reaction, addressing the issues of high reaction temperature and over-reliance on fossil energy in acetone aldehyde production.

[0005] A method for the continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol, characterized by comprising the following steps:

[0006] Pure glycerol or a glycerol solution is vaporized to form raw material vapor;

[0007] The raw material vapor is mixed with an O2-containing gas to form a mixed gas;

[0008] The mixed gas is contacted with a supported gold nanoparticle catalyst to carry out a selective oxidation reaction to prepare the acetone aldehyde, wherein the support for the supported gold nanoparticle catalyst is a metal oxide.

[0009] In some embodiments, the solvent of the glycerol solution includes one or more of water, N,N-dimethylformamide, and 1,4-dioxane; preferably, the solvent is water.

[0010] In some embodiments, the glycerol solution has a molar ratio of 0 ≤ solvent to glycerol ≤ 60.

[0011] In some embodiments, the O2-containing gas is pure O2 or air.

[0012] In some embodiments, the molar ratio of O2 to glycerol in the mixed gas is 0.2 ≤ 60.

[0013] In some embodiments, the partial pressure of glycerol in the selective oxidation reaction is 0.5 kPa to 10.0 kPa; preferably, the partial pressure of glycerol in the selective oxidation reaction is 0.8 kPa to 5.1 kPa.

[0014] In some embodiments, the space velocity of the selective oxidation reaction is 8000 mL·g. cat -1 ·h -1 ~400000mL·g cat -1 ·h -1 Preferably, the space velocity of the selective oxidation reaction is 20000 mL·g. cat -1 ·h -1 ~160000mL·g cat -1 ·h -1 .

[0015] In some embodiments, the temperature of the selective oxidation reaction is 210°C to 320°C; preferably, the temperature of the selective oxidation reaction is 230°C to 280°C.

[0016] In some embodiments, the gold nanoparticles in the supported gold nanoparticle catalyst are elemental metals or alloys.

[0017] In some embodiments, the supported gold nanoparticle catalyst has an Au loading of 0.1 wt.% ≤ 16 wt.%.

[0018] In some embodiments, the metal oxide includes one or more of ZrO2, TiO2, ZnO, NiO, Nb2O5, Co3O4, and Al2O3; preferably, the metal oxide is one or more of ZrO2, TiO2, and ZnO.

[0019] In the above-described method for the continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol, vaporized glycerol undergoes selective oxidation on a metal oxide-supported gold nanoparticle catalyst to generate acetone aldehyde. This reaction can be carried out at relatively low temperatures and under mild conditions; the reactant glycerol is derived from renewable biomass resources, making it inexpensive and readily available, thus representing a green and economical method for preparing acetone aldehyde. Detailed Implementation

[0020] To facilitate understanding of this application, a more comprehensive description of the application is provided below with reference to embodiments. This application can be implemented in many different forms and is not limited to the embodiments described herein. The terminology used in this application's specification is intended to describe the purposes of the embodiments and is not intended to limit the application.

[0021] This application provides a method for the continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol, comprising the following steps: vaporizing pure glycerol or a glycerol solution to form raw material vapor; mixing the raw material vapor with a gas containing O2 to form a mixed gas; contacting the mixed gas with a supported nano-gold catalyst to carry out a selective oxidation reaction to prepare the acetone aldehyde, wherein the support for the supported nano-gold catalyst is a metal oxide.

[0022] Glycerol is a coproduct of biodiesel, produced during the hydrolysis of animal and vegetable oils (biomass), with a yield of approximately 1 / 10 of that of biodiesel. With the expanding market demand for biodiesel and its surging production, glycerol has become a cheap and readily available synthetic raw material. Glycerol oxidation has also become an economical and environmentally friendly method for preparing acetone aldehyde. Therefore, this application provides a continuous synthetic method for preparing acetone aldehyde based on the gas-phase oxidation reaction of glycerol.

[0023] In some embodiments, the solvent for the glycerol solution is one or more of water, N,N-dimethylformamide, and 1,4-dioxane. Preferably, the solvent is water.

[0024] In some embodiments, in the glycerol solution, 0 ≤ the molar ratio of solvent to glycerol ≤ 60. It is understood that the molar ratio of solvent to glycerol in the glycerol solution is 2:1, 3:1, 9:1, 10:1, 14:1, 18:1, 20:1, 22:1, 25:1, 28:1, 31:1, 33:1, 35:1, 37:1, 39:1, 42:1, 46:1, 50:1, 54:1, 58:1, 60:1, etc., and is not limited thereto.

[0025] Understandably, the vaporization of the pure glycerol or glycerol solution can be performed either inside or outside the reactor used for selective oxidation reactions, as long as the raw material vapor is formed before contact with the catalyst.

[0026] Furthermore, the reactor may be a fixed-bed reactor, a fluidized-bed reactor, a moving-bed reactor, etc., and is not limited thereto.

[0027] In some embodiments, the O2-containing gas is pure O2 or air.

[0028] In some embodiments, the molar ratio of O2 to glycerol in the mixed gas is 0.2 ≤ 60. It is understood that the molar ratio of O2 to glycerol in the mixed gas is 0.2:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, 30:1, 40:1, 48:1, 53:1, 60:1, etc., and is not limited thereto.

[0029] In some embodiments, the partial pressure of glycerol in the selective oxidation reaction is 0.5 kPa to 10.0 kPa. It is understood that the partial pressure of glycerol in the selective oxidation reaction can be 0.5 kPa, 0.8 kPa, 1 kPa, 1.5 kPa, 1.7 kPa, 3 kPa, 5 kPa, 5.1 kPa, 6 kPa, 7 kPa, 8 kPa, 9 kPa, 10 kPa, etc., and is not limited thereto. Preferably, the partial pressure of glycerol in the selective oxidation reaction is 0.8 kPa to 5.1 kPa.

[0030] In some embodiments, the mixed gas further includes a carrier gas. More specifically, the carrier gas is N2, CO2, air, etc.

[0031] In some embodiments, the space velocity of the selective oxidation reaction is 8000 mL·g. cat -1 ·h -1 ~400000mL·g cat -1 ·h -1 Understandably, the space velocity for the selective oxidation reaction is 8000 mL·g⁻¹. cat -1 ·h -1 12000mL·g cat -1 ·h -1 16000mL·g cat -1 ·h -1 20000mL·g cat -1 ·h -1 32000mL·g cat -1 ·h -1 40000mL·g cat -1 ·h -1 80000mL·gcat -1 ·h -1 160000mL·g cat -1 ·h -1 200000mL·g cat -1 ·h -1 300000mL·g cat -1 ·h -1 400000mL·g cat -1 ·h -1 And so on, but not limited to these. Preferably, the space velocity of the selective oxidation reaction is 20000 mL·g. cat -1 ·h -1 ~160000mL·g cat -1 ·h -1 .

[0032] In some embodiments, the temperature of the selective oxidation reaction is 210°C to 320°C. It is understood that the temperature of the selective oxidation reaction can be 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, 320°C, etc., and is not limited thereto. Preferably, the temperature of the selective oxidation reaction is 230°C to 280°C.

[0033] In some embodiments, the gold nanoparticles in the supported gold nanoparticle catalyst are elemental metals or alloys. Further, in the supported gold nanoparticle catalyst, the loading of Au is 0.1 wt.% ≤ 16 wt.%. It is understood that the loading of Au can be 0.9 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, 15 wt.%, 16 wt.%, etc., and is not limited thereto.

[0034] In some embodiments, the metal oxide is one or more selected from ZrO2, TiO2, ZnO, NiO, Nb2O5, Co3O4, and Al2O3. Preferably, the metal oxide is one or more selected from ZrO2, TiO2, and ZnO.

[0035] The catalyst and the support in the catalyst can be independently derived from commercially available sources or prepared in-house. In-house preparation methods include precipitation, co-precipitation, deposition precipitation, impregnation, etc., and are not limited thereto.

[0036] In some embodiments, the acetone aldehydes obtained from the selective oxidation reaction are collected by solvent trapping or condensation.

[0037] The method for the continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to this application will be further described in detail below with reference to specific embodiments and comparative examples. It will be understood that, in the specific embodiments, unless otherwise specified, all raw materials are commercially available.

[0038] Example 1

[0039] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0040] 1. Preparation of a support for the supported gold nanoparticle catalyst: 500 mL of 0.078 mol·L⁻¹ gold nanoparticle support was prepared. -1 A ZrO(NO3)2 aqueous solution and 500 mL of a 2.5 wt.% ammonia aqueous solution were mixed evenly and aged for 12 h. After multiple washings, a ZrO(OH)2 hydrogel was obtained. The ZrO(OH)2 hydrogel was dried and then calcined at 450 °C for 5 h to obtain a ZrO2 support, labeled ZrO2-CP, where CP specifically refers to the sample prepared from the ZrO(OH)2 hydrogel.

[0041] 2. Loading of gold nanoparticles: Taking the preparation of 1g of catalyst with a loading of 1wt.% as an example, 0.99g of ZrO2-CP obtained in step 1, 1.22g of urea and 50mL of deionized water were mixed evenly, and then 1mL of 10mg gold nanoparticles was added. Au ·mL -1 A HAuCl4 solution was used to obtain a mixed solution. The mixed solution was stirred at 80℃ for 6 h and then aged for 12 h. After multiple washings and drying, the sample was aged at 400℃ for 65 mL / min. -1 The catalyst was calcined in air for 5 hours to obtain a supported gold nanoparticle catalyst with ZrO2 as the support. The catalyst was labeled as Au / ZrO2-CP.

[0042] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0043] The gas-phase oxidation of glycerol to prepare acetone aldehyde was carried out in a continuous flow fixed-bed reactor, which was a straight quartz tube with a length of 65 cm and an inner diameter of 8 mm. The reaction was conducted under atmospheric pressure, and the specific operating steps are as follows:

[0044] 1. Dilute 52.7 mg of Au / ZrO2-CP obtained in step one with quartz sand to a total volume of 1 mL, mix evenly, and fill the middle of the reactor to form a catalyst bed, with the lower part supported by quartz wool; fill the upper part with 10 g of quartz sand as the raw material vaporization zone, and fix the reactor in the constant temperature zone of the tubular heater.

[0045] 2. The catalyst was subjected to a temperature of 300℃ and a concentration of 30 mL / min. -1 The catalyst was purged with N2 for 1.5 h to remove impurities from the catalyst surface, and then cooled to the reaction temperature (260 °C). A 10 wt.% glycerol aqueous solution was injected into the reactor using a micro-injection pump. The feedstock formed feed vapor in the vaporization zone and was uniformly mixed with O2 and N2 (carrier gas). The mixed gas then passed through the catalyst bed for selective oxidation to produce acetone aldehyde. During the reaction, the flow rates of the micro-injection pump, O2, and N2 were controlled to maintain a glycerol partial pressure of 1.0 kPa, an H2O / O2 / glycerol (molar ratio) of 46 / 8 / 1, and a space velocity of 80000 mL·g. cat -1 ·h -1 The reaction products were collected using a condenser placed in an ice-water bath at 0°C. The reaction results were analyzed by liquid chromatography, and the results are shown in Table 1.

[0046] Table 1 Performance of Glycerol Vapor-Phase Oxidation to Pyronealdehyde on Au / ZrO2-CP

[0047]

[0048] As shown in Table 1, the glycerol conversion on the Au / ZrO2-CP catalyst reached a stable state after 12 hours of reaction, the acetone aldehyde selectivity reached a stable state after 69 hours of reaction, and the catalyst remained stable after 215 hours of reaction.

[0049] Example 2

[0050] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0051] 1. Preparation of a support for the supported gold nanoparticle catalyst: The ZrO(OH)₂ hydrogel obtained in step one of Example 1 was washed three times with ethanol, and then refluxed in ethanol at 75°C for 3 h to obtain a ZrO(OH)₂ ethanol gel. After drying, the ZrO(OH)₂ ethanol gel was calcined at 450°C for 5 h to obtain a ZrO₂ support, labeled as ZrO₂-AD, where AD specifically refers to the sample prepared from the ZrO(OH)₂ ethanol gel.

[0052] 2. Loading of gold nanoparticles: The steps for loading gold nanoparticles are basically the same as step one of Example 1, except that: In Example 2, by adjusting the amount of HAuCl4 solution added, catalysts with loading amounts of 1wt.%, 6wt.%, and 16wt.% were obtained, and labeled as 1Au / ZrO2-AD, 6Au / ZrO2-AD, and 16Au / ZrO2-AD, respectively. The first number of the label indicates the loading amount of Au.

[0053] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0054] The procedure was the same as step two in Example 1. Samples were taken for analysis after the reaction had continued for 3 hours, and the results are shown in Table 2.

[0055] Table 2 Effect of Au loading on Au / ZrO2-AD catalytic performance

[0056]

[0057] As shown in Table 2, the higher the Au loading, the higher the yield of acetone aldehyde.

[0058] Example 3

[0059] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0060] The catalyst used was commercially available, specifically Au / ZrO2 produced by AuTEK Associates, with an Au loading of 1 wt.% and labeled Au / ZrO2-AuTEK.

[0061] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0062] The procedure is basically the same as step two in Example 1, except that the space velocity is 20000 mL·g. cat -1 ·h -1 80000mL·g cat -1 ·h -1 120000mL·g cat -1 ·h -1 Samples were taken and analyzed after the reaction lasted for 3 hours. The results are shown in Table 3.

[0063] Table 3 Effect of space velocity on the catalytic performance of Au / ZrO2-AuTEK

[0064]

[0065]

[0066] As shown in Table 3, the lower the space velocity, the higher the glycerol conversion rate, while the selectivity of acetone aldehyde changes little with space velocity, indicating that under the conditions of this embodiment, reducing the space velocity is beneficial to the formation of acetone aldehyde.

[0067] Example 4

[0068] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0069] The catalyst is the same as that provided in step one of Example 3.

[0070] Step 2: Continuous preparation of acetone aldehyde based on gas-phase glycerol oxidation reaction

[0071] The procedure is basically the same as step two in Example 1, except that the space velocity is 40000 mL·g. cat -1 ·h -1 The O2 / glycerol (molar ratio) was 11.2 / 1. No additional carrier gas was used when the O2-containing gas was air; when the O2-containing gas was pure oxygen, N2 was used as the carrier gas. Samples were taken and analyzed after the reaction lasted for 3 hours, and the results are shown in Table 4.

[0072] Table 4. Effect of O2-containing gas type on the catalytic performance of Au / ZrO2-AuTEK

[0073]

[0074] As shown in Table 4, under the same conditions, the conversion rate of glycerol and the selectivity of acetone aldehyde are similar when the gas containing O2 is pure oxygen and air, indicating that oxygen in the air and pure oxygen have similar functions.

[0075] Example 5

[0076] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0077] The catalyst is the same as that provided in step one of Example 3.

[0078] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0079] The procedure is basically the same as step two in Example 1, except that the space velocity is 120,000 mL·g. cat -1 ·h -1 The molar ratios of O2 to glycerol were 0.5 / 1, 8 / 1, and 53 / 1. Samples were taken for analysis after the reaction had continued for 3 hours, and the results are shown in Table 5.

[0080] Table 5 Effect of O2 to glycerol molar ratio on the catalytic performance of Au / ZrO2-AuTEK

[0081]

[0082] As shown in Table 5, both the glycerol conversion rate and the acetone aldehyde selectivity increased with the increase of the O2 to glycerol molar ratio, indicating that under the conditions of this embodiment, increasing the O2 to glycerol molar ratio is beneficial to the formation of acetone aldehyde.

[0083] Example 6

[0084] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0085] The catalyst is the same as that provided in step one of Example 3.

[0086] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0087] The procedure is basically the same as step two in Example 1, except that the space velocity is 160,000 mL·g. cat -1 ·h -1 The O2 / glycerol (molar ratio) was 2 / 1, and the reaction temperatures were 220℃, 250℃, and 280℃. Samples were taken for analysis after the reaction lasted for 3 hours, and the results are shown in Table 6.

[0088] Table 6. Effect of temperature on the catalytic performance of Au / ZrO2-AuTEK

[0089]

[0090] As can be seen from Table 6, the higher the reaction temperature, the higher the glycerol conversion rate and the acetone aldehyde selectivity, indicating that under the conditions of this example, increasing the temperature is beneficial to the formation of acetone aldehyde.

[0091] Example 7

[0092] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0093] The catalyst is the same as that provided in step one of Example 3.

[0094] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0095] The procedure was essentially the same as step two in Example 1, except that H2O or 1,4-dioxane was used as the solvent, the solvent / glycerol (molar ratio) was 20 / 1, and the boiling point of the raw material was approximately 140°C. Samples were taken for analysis after the reaction had continued for 3 hours, and the results are shown in Table 7.

[0096] Table 7. Effect of solvent on the catalytic performance of Au / ZrO2-AuTEK

[0097]

[0098] As shown in Table 7, under the same conditions, the glycerol conversion rate and acetone aldehyde selectivity were lower when 1,4-dioxane was used as the solvent than when H2O was used as the solvent. This indicates that under the conditions of this example, using water as the solvent is more conducive to the formation of acetone aldehyde.

[0099] Example 8

[0100] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0101] The catalyst is the same as that provided in step one of Example 3.

[0102] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0103] The procedure is basically the same as step two in Example 1, except that the partial pressure of glycerol is 2.0 kPa and the space velocity is 160,000 mL·g. cat -1 ·h -1 The molar ratio of O2 to glycerol was 2 / 1, the reaction temperature was 280℃, and the molar ratios of H2O and glycerol were 2 / 1, 9 / 1, and 31 / 1, respectively. Samples were taken for analysis after 3 hours, and the results are shown in Table 8.

[0104] Table 8 Effect of the molar ratio of H2O to glycerol on the catalytic performance of Au / ZrO2-AuTEK

[0105]

[0106]

[0107] As can be seen from Table 8, the higher the molar ratio of H2O to glycerol, the higher the glycerol conversion rate and the selectivity of acetone aldehyde, indicating that under the conditions of this embodiment, increasing the molar ratio of H2O to glycerol is beneficial to the formation of acetone aldehyde.

[0108] Example 9

[0109] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0110] The catalyst is the same as that provided in step one of Example 3.

[0111] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0112] The procedure is basically the same as step two in Example 1, except that the space velocity is 32000 mL·g. cat -1 ·h -1 The reaction temperature was 280℃, the H2O / glycerol (molar ratio) was 12 / 1, and the partial pressures of glycerol were 0.8 kPa, 1.7 kPa, and 5.1 kPa. Samples were taken for analysis after the reaction lasted for 3 hours, and the results are shown in Table 9.

[0113] Table 9. Effect of glycerol partial pressure on the catalytic performance of Au / ZrO2-AuTEK

[0114]

[0115] As shown in Table 9, both the glycerol conversion rate and the acetone aldehyde selectivity decreased with increasing glycerol partial pressure, indicating that under the conditions of this embodiment, reducing the partial pressure of glycerol is beneficial to the formation of acetone aldehyde.

[0116] Example 10

[0117] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0118] The catalyst used was commercially available, specifically Au / TiO2 produced by AuTEK Associates, with an Au loading of 0.9 wt.%, labeled Au / TiO2-AuTEK.

[0119] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0120] The procedure is the same as step two in Example 1.

[0121] Example 11

[0122] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0123] The catalyst is the same as that provided in step one of Example 10.

[0124] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0125] The reaction is basically the same as step two in Example 1, except that the reaction temperature is 240°C.

[0126] Example 12

[0127] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0128] The catalyst used was commercially available, specifically Au / ZnO produced by AuTEK Associates, with an Au loading of 1 wt.% and labeled Au / ZnO-AuTEK.

[0129] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0130] The procedure is the same as step two in Example 1.

[0131] Example 13

[0132] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0133] The catalyst is the same as that provided in step one of Example 12.

[0134] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0135] The reaction is basically the same as step two in Example 1, except that the reaction temperature is 280°C.

[0136] Example 14

[0137] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0138] 1. Support for the preparation of supported gold nanoparticle catalysts

[0139] The preparation steps of the support are basically the same as those in step one of Example 2, except that the ZrO(NO3)2 aqueous solution is replaced with Ni(NO3)2 aqueous solution, and the resulting support is labeled as NiO.

[0140] 2. Loading of gold nanoparticles:

[0141] The catalyst was labeled Au / NiO, which is the same as the gold nanoparticle loading step in Step 1 of Example 1.

[0142] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0143] The procedure is the same as step two in Example 1.

[0144] Example 15

[0145] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0146] 1. Preparation of supports for supported gold nanoparticle catalysts:

[0147] The Nb2O5·nH2O produced by Ningxia Oriental Tantalum Industry Co., Ltd. was calcined in flowing N2 at 350℃ for 4 hours to obtain the Nb2O5 support.

[0148] 2. Loading of gold nanoparticles:

[0149] The catalyst was labeled Au / Nb2O5, which is the same as the gold nanoparticle loading step in Step 1 of Example 1.

[0150] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0151] The process is essentially the same as step two in Example 1, except that the reaction temperature is 265°C, the O2 / glycerol (molar ratio) is 2 / 1, and the space velocity is 16000 mL·g.cat -1 ·h -1 .

[0152] Example 16

[0153] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0154] 1. Preparation of supports for supported gold nanoparticle catalysts:

[0155] At a concentration of 0.1 mol·L⁻¹ in 500 mL -1 Add 1 mol·L⁻¹ to the Co(NO₃)₂ solution -1 The sample was stirred in Na2CO3 solution until pH=10, then aged for 12 hours after stirring for 30 minutes. After multiple washings and drying, the sample was calcined in flowing N2 at 400℃ to obtain the Co3O4 support.

[0156] 2. Loading of gold nanoparticles:

[0157] The catalyst was labeled Au / Co3O4, which is the same as the gold nanoparticle loading step in Step 1 of Example 1.

[0158] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0159] The procedure is the same as step two in Example 1.

[0160] Example 17

[0161] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0162] 1. Preparation of supports for supported gold nanoparticle catalysts:

[0163] 100 mL of a 1 mol·L⁻¹ solution -1 Add 100 mL of 2 mol·L⁻¹ NaOH dropwise to Al(NO₃)₃ solution. -1 ) and Na2CO3 (0.4 mol·L -1 The mixture was aged at 65°C for 18 hours, then washed and dried repeatedly, followed by incubation at 600°C and 65 mL / min. -1 The Al2O3 support was obtained by calcining in air for 5 hours.

[0164] 2. Loading of gold nanoparticles:

[0165] The catalyst was labeled Au / Al2O3, which is the same as the gold nanoparticle loading step in Step 1 of Example 1.

[0166] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0167] The reaction is basically the same as step two in Example 1, except that the reaction temperature is 240°C.

[0168] Comparative Example 1

[0169] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0170] The catalyst used was commercially available, specifically Au / C produced by Haruta Gold Incorporated, with an Au loading of 1 wt.% and labeled Au / C-Haruta.

[0171] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0172] The procedure is the same as step two in Example 1.

[0173] Comparative Example 2

[0174] Step 1: Obtaining supported gold nanoparticle catalysts using metal oxides as supports

[0175] The catalyst used was the same as that provided in step one of Comparative Example 1.

[0176] Step 2: Continuous preparation of acetone aldehyde based on glycerol gas-phase oxidation reaction

[0177] The process is essentially the same as step two in Example 1, except that the reaction temperature is 240°C, the O2 / glycerol (molar ratio) is 3 / 1, and the space velocity is 400,000 mL·g. cat -1 ·h -1 .

[0178] Samples were taken and analyzed after the reactions in Examples 10 to 17 and Examples 1 to 2 were carried out for 3 hours. The results are shown in Table 10.

[0179] Table 10. Effect of support on the performance of gold catalysts

[0180]

[0181] As shown in Table 10, the selectivity of acetone aldehyde is higher on the gold nanocatalyst supported by metal oxides, while the selectivity of acetone aldehyde is lower on Au / C-Haruta, indicating that using metal oxides as supports is more conducive to the formation of acetone aldehyde.

[0182] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0183] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for the continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol, characterized in that, Includes the following steps: Pure glycerol or a glycerol solution is vaporized to form raw material vapor; The raw material vapor is mixed with an O2-containing gas to form a mixed gas; The mixed gas is contacted with a supported gold nanoparticle catalyst to carry out a selective oxidation reaction to prepare the acetone aldehyde. The supported gold nanoparticle catalyst is supported on a metal oxide. The temperature of the selective oxidation reaction is 260℃~280℃. The partial pressure of glycerol in the selective oxidation reaction is 0.5kPa~1.7kPa. In the mixed gas, the molar ratio of O2 to glycerol is ≤60.

2. The method for continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to claim 1, characterized in that, The solvent for the glycerol solution includes one or more of water, N,N-dimethylformamide, and 1,4-dioxane.

3. The method for continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to claim 2, characterized in that, In the glycerol solution, 0 ≤ the molar ratio of solvent to glycerol ≤ 60.

4. The method for continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to claim 1, characterized in that, In the mixed gas, the molar ratio of O2 to glycerol is ≤53.

5. The method for continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to claim 1, characterized in that, The partial pressure of glycerol in the selective oxidation reaction is 0.5 kPa to 0.8 kPa.

6. The method for continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to claim 1, characterized in that, The space velocity of the selective oxidation reaction is 8000 mL·g. cat -1 ·h -1 ~400000 mL·g cat -1 ·h -1 .

7. The method for continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to claim 1, characterized in that, The space velocity of the selective oxidation reaction is 20000 mL·g. cat -1 ·h -1 ~160000 mL·g cat -1 ·h -1 .

8. The method for continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to claim 1, characterized in that, The gold nanoparticles in the supported gold nanoparticle catalyst are either elemental metals or alloys.

9. The method for continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to claim 8, characterized in that, In the supported gold nanocatalyst, the loading of Au is 0.1 wt.% ≤ 16 wt.%.

10. The method for continuous preparation of acetone aldehyde based on the gas-phase oxidation reaction of glycerol according to any one of claims 1 to 9, characterized in that, The metal oxide includes one or more of ZrO2, TiO2, ZnO, NiO, Nb2O5, Co3O4, and Al2O3.

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