Preparation method and application of catalyst for decarbonylation of methyl formate
By preparing a modified composite alumina supported catalyst loaded with alkali metal active components, the problem of high cost of precious metal catalysts in the prior art was solved, and a highly efficient and stable reaction of methyl formate to methanol and carbon monoxide was achieved. The catalyst has excellent and stable performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI HUAYI ENERGY CHEM
- Filing Date
- 2024-11-18
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methyl formate decarbonylation catalysts contain expensive precious metal components, which increases preparation costs. Furthermore, current technologies struggle to achieve efficient and stable conversion of methyl formate into methanol and carbon monoxide.
A modified composite alumina supported catalyst loaded with alkali metal active components was prepared by equal-volume impregnation and calcination. The catalyst included multiple loadings of the modified additives and alkali metal active components and was used for the decarbonylation reaction of methyl formate.
The reaction of methyl formate to methanol and carbon monoxide was achieved with high efficiency, with a conversion rate of nearly 100% and a methanol selectivity of over 98%. The catalyst performance was stable and did not deactivate after 1000 hours of operation.
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of catalyst preparation, and relates to a method for preparing a catalyst for the decarbonylation of methyl formate and its application, specifically a catalyst for the decarbonylation of methyl formate to produce methanol and carbon monoxide, and its preparation method and application. Background Technology
[0002] The process of preparing ethylene glycol by hydrogenating oxalate esters from syngas is an economical and efficient route for synthesizing ethylene glycol that has been developed in recent years. It is particularly suitable for China's resource conditions of being rich in coal but poor in oil, and has been widely promoted and applied in industrial production in China.
[0003] In the coal-based ethylene glycol route, the carbonyl synthesis of dimethyl oxalate produces a certain amount of methyl formate (MF) as a byproduct, which accumulates within the system, affecting system equilibrium. Furthermore, the hydrolysis products of MF severely corrode the equipment. Treatment methods such as thaw or distillation followed by incineration not only increase material consumption but also fail to meet the economic requirements of the process. Therefore, developing a simple and efficient catalyst to generate high-purity methanol and carbon monoxide from methyl formate via a decarbonylation reaction, with the products separated into liquid and gas phases after condensation, allows the liquid product methanol to be returned to the esterification system and the gaseous product carbon monoxide to be returned to the carbonylation system. Alternatively, after further purification, the high-purity methanol and carbon monoxide can be incorporated into the carbonyl synthesis of acetic acid production system, which is of great significance for reducing carbon emissions.
[0004] There are few reported methods for converting methyl formate to methanol and CO via direct decarbonylation. Patent CN114315511A discloses a method for producing high-purity methanol and CO from methyl formate via decarbonylation. In this method, MF is vaporized, preheated, and then decomposed on a dedicated catalyst to generate CO and methanol. The reaction gas is cooled and then separated into gas and liquid phases. The purified gas enters a carbonylation system, while the byproduct methanol is recycled through an esterification system. The dedicated catalyst consists of an active component, an active additive, and a support. The active component comprises 10%–20% by mass of the support, and the active additive comprises 0.5%–2% by mass. The introduction of the active additive significantly improves the catalyst lifespan. US Patent 4999177 discloses a catalyst in which 0.02% (w) of Pt, Ir, or Ru compounds are supported on a neutral or basic support, with 0.1% to 10% (w) of an alkali or alkaline earth metal compound as an auxiliary agent. Methyl formate undergoes decarbonylation upon heating at 150–350 °C to yield CO with a purity greater than 99% (mol). All of the aforementioned prior art methyl formate decarbonylation catalysts utilize precious metal components, resulting in high costs and increasing the catalyst preparation cost. Summary of the Invention
[0005] In view of the characteristics of the prior art described above, the purpose of this invention is to provide a method for preparing a catalyst for the decarbonylation of methyl formate and its application, which can participate in the decarbonylation reaction of methyl formate to prepare methanol and CO, and has good reactivity in the decarbonylation reaction of methyl formate.
[0006] To achieve the above and other related objectives, the first aspect of the present invention provides a catalyst for the decarbonylation of methyl formate, comprising a modified composite alumina support loaded with an alkali metal active component, conforming to the general chemical structural formula: M1 / M2-γ-Al2O3, wherein M1 is the alkali metal active component, M2 is a modifying agent, and M2-γ-Al2O3 is an M2 modified composite alumina support.
[0007] A second aspect of the present invention provides a method for preparing a catalyst for the decarbonylation of methyl formate, comprising the following steps:
[0008] 1) Carrier modification: The alumina carrier is impregnated in an aqueous solution of the modifying agent by an equal volume impregnation method, followed by drying and calcination to provide a modified composite alumina carrier.
[0009] 2) Loading of alkali metal active components: The modified composite alumina support obtained in step 1) is impregnated in an alcohol solution of alkali metal active components at least once using the equal volume impregnation method, followed by drying and calcination, to provide the required catalyst.
[0010] A third aspect of the present invention provides the use of a catalyst for the decarbonylation of methyl formate in the preparation of methanol and carbon monoxide from the decarbonylation reaction of methyl formate.
[0011] The fourth aspect of the present invention provides a method for preparing methanol and carbon monoxide by decarbonylation reaction of methyl formate, comprising: carrying out a decarbonylation reaction of methyl formate or a mixture of methyl formate and methanol under the action of the above-mentioned catalyst, followed by condensation and gas-liquid separation to obtain methanol in liquid phase and carbon monoxide in gas phase, respectively.
[0012] As described above, the present invention provides a method for preparing a catalyst for the decarbonylation of methyl formate and its application. The catalyst system is simple to prepare and use, and can participate in the reaction of methyl formate decarbonylation to directly produce methanol and CO. It has good reactivity in the decarbonylation reaction of methyl formate. When used in a gas-solid phase system to realize the decarbonylation reaction of methyl formate, the conversion rate and selectivity are excellent, reaching a conversion rate of nearly 100% formate and a methanol selectivity of more than 98%. Moreover, the reaction performance is stable, and no catalyst deactivation was observed after 1000 hours of operation. Attached Figure Description
[0013] Figure 1 The diagram shows the activity and stability of the catalyst prepared in Example 5 of this invention. Detailed Implementation
[0014] The first aspect of the present invention provides a catalyst for the decarbonylation of methyl formate, comprising a modified composite alumina support loaded with an alkali metal active component, conforming to the general chemical structural formula: M1 / M2-γ-Al2O3, wherein M1 is the alkali metal active component, M2 is a modifying agent, and M2-γ-Al2O3 is the M2 modified composite alumina support.
[0015] In the above-mentioned catalyst, the catalyst is a supported solid base catalyst.
[0016] In the above catalyst, the alkali metal active component is an alkali metal organic salt.
[0017] In one embodiment, the alkali metal active component is selected from one or more combinations of sodium methoxide, potassium methoxide, or potassium tert-butoxide, preferably one or two combinations of sodium methoxide, potassium methoxide, or potassium tert-butoxide.
[0018] In the above catalyst, the modifying agent is selected from one or more combinations of soluble salts of lithium (Li), magnesium (Mg) or lanthanum (La), preferably one or two combinations of soluble salts of lithium (Li), magnesium (Mg) or lanthanum (La).
[0019] In one embodiment, the soluble salt of lithium (Li), magnesium (Mg) or lanthanum (La) is selected from at least one of chloride, nitrate or acetate.
[0020] In a further preferred embodiment, the soluble salt of lithium is selected from one or a combination of two of lithium nitrate or lithium chloride.
[0021] In a further preferred embodiment, the soluble salt of magnesium is magnesium nitrate.
[0022] In a further preferred embodiment, the soluble salt of lanthanum is lanthanum nitrate.
[0023] In the above catalyst, the loading of M1 on the alumina support is 10-30 wt%, specifically 10-15 wt%, 15-20 wt%, 20-25 wt%, and 25-30 wt%.
[0024] In the above catalyst, the loading of M2 on the alumina support is 1-5 wt%, specifically 1-2 wt%, 2-3.5 wt%, or 3.5-5 wt%.
[0025] A second aspect of the present invention provides a method for preparing the above-mentioned catalyst, comprising the following steps:
[0026] 1) Carrier modification: The alumina carrier is impregnated in an aqueous solution of the modifying agent by an equal volume impregnation method, followed by drying and calcination to provide a modified composite alumina carrier.
[0027] 2) Loading of alkali metal active components: The modified composite alumina support obtained in step 1) is impregnated in an alcohol solution of alkali metal active components at least once using the equal volume impregnation method, followed by drying and calcination, to provide the required catalyst.
[0028] In step 1) or 2) above, the isovolumetric impregnation method is a conventional isovolumetric impregnation method. Its principle is that the volume of the impregnating liquid is equal to the pore volume of the solid support, which is a conventional catalyst preparation method.
[0029] In step 1) above, the modifying agent is selected from one or more combinations of soluble salts of lithium (Li), magnesium (Mg) or lanthanum (La), preferably one or two combinations of soluble salts of lithium (Li), magnesium (Mg) or lanthanum (La).
[0030] In one embodiment, the soluble salt of lithium (Li), magnesium (Mg) or lanthanum (La) is selected from at least one of chloride, nitrate or acetate.
[0031] In a further preferred embodiment, the soluble salt of lithium is selected from one or a combination of two of lithium nitrate or lithium chloride.
[0032] In a further preferred embodiment, the soluble salt of magnesium is magnesium nitrate.
[0033] In a further preferred embodiment, the soluble salt of lanthanum is lanthanum nitrate.
[0034] In step 1) above, the concentration of the metal element in the aqueous solution of the modified additive is 1.18-5.88 wt%, specifically 1.18-2.35 wt%, 2.35-4.12 wt%, and 4.12-5.88 wt%.
[0035] In step 1) above, the soaking time is 0.5-4 hours, specifically 0.5-1 hour, 1-2 hours, 2-3 hours, or 3-4 hours.
[0036] In step 1) above, the drying method is to evaporate the moisture by ultrasonic heating.
[0037] In step 1) above, the drying temperature is 80-90℃, specifically 80-85℃ or 85-90℃.
[0038] In step 1) above, the drying time is 3-5 hours, specifically 3-4 hours or 4-5 hours.
[0039] In step 1) above, the roasting is carried out in an air atmosphere.
[0040] In step 1) above, the roasting temperature is 400-700℃, specifically 400-500℃, 500-600℃, or 600-700℃.
[0041] In step 1) above, the roasting time is 2-6 hours, specifically 2-3 hours, 3-4 hours, 4-5 hours, or 5-6 hours.
[0042] In step 2) above, the alkali metal active component is an alkali metal organic salt.
[0043] In one embodiment, the alkali metal active component is selected from one or more combinations of sodium methoxide, potassium methoxide, or potassium tert-butoxide, preferably one or two combinations of sodium methoxide, potassium methoxide, or potassium tert-butoxide.
[0044] In step 2) above, the alcohol in the alcohol solution of the alkali metal active component is anhydrous methanol.
[0045] In step 2) above, the concentration of the alkali metal active component in the alcohol solution of the alkali metal active component is 5.88-29.41 wt%, specifically 5.88-15 wt%, 15-20 wt%, 20-25 wt%, and 25-29.41 wt%.
[0046] In step 2) above, the soaking time is 0.5-4 hours, specifically 0.5-1 hour, 1-2 hours, 2-3 hours, or 3-4 hours.
[0047] In step 2) above, the drying method is to evaporate the alcohol by ultrasonic heating.
[0048] In step 2) above, the drying temperature is 80-90℃, specifically 80-85℃ or 85-90℃.
[0049] In step 2) above, the drying time is 3-5 hours, specifically 3-4 hours or 4-5 hours.
[0050] In step 2) above, the calcination is carried out under a nitrogen atmosphere.
[0051] In step 2) above, the roasting temperature is 150-250℃, specifically 150-200℃ or 200-250℃.
[0052] In step 2) above, the roasting time is 2-4 hours, specifically 2-3 hours or 3-4 hours.
[0053] In step 2) above, the alkali metal active component is loaded 1-2 times.
[0054] In step 2) above, when the alkali metal active component is loaded at least twice, the alcohol solutions of the alkali metal active component in different loadings can be the same or different, and the impregnation, drying and calcination conditions in different loadings can be the same or different.
[0055] A third aspect of the present invention provides the use of the above-mentioned catalyst in the decarbonylation reaction of methyl formate to prepare methanol and carbon monoxide.
[0056] The fourth aspect of the present invention provides a method for preparing methanol and carbon monoxide by decarbonylation reaction of methyl formate, comprising: carrying out a decarbonylation reaction of methyl formate or a mixture of methyl formate and methanol under the action of the above-mentioned catalyst, followed by condensation and gas-liquid separation to obtain methanol in liquid phase and carbon monoxide in gas phase, respectively.
[0057] In the above method, the decarbonylation reaction is carried out in a fixed-bed reactor.
[0058] In the above method, the weight percentage of methanol in the mixture of methyl formate and methanol is >0 and ≤70%.
[0059] In the above method, the temperature of the decarbonylation reaction is 200-280℃, specifically 200-280℃, 200-220℃, 220-240℃, 240-260℃, and 260-280℃.
[0060] In the above method, the reaction pressure of the decarbonylation reaction is 0.3-1.0 MPa, specifically 0.3-0.4 MPa, 0.4-0.5 MPa, 0.5-0.6 MPa, 0.6-0.7 MPa, 0.7-0.8 MPa, 0.8-0.9 MPa, or 0.9-1.0 MPa.
[0061] In the above method, the liquid space velocity of the feedstock for the decarbonylation reaction is 1-3 h⁻¹. -1 Specifically, such as 1-2 hours -1 2-3h -1 .
[0062] In the above method, the liquid methanol is returned to the esterification system, and the gaseous carbon monoxide is returned to the carbonylation system, or after further purification, high-purity methanol and carbon monoxide are incorporated into the carbonyl synthesis acetic acid production system.
[0063] The water used above is deionized water.
[0064] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.
[0065] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.
[0066] Example 1
[0067] 30.28g of lithium chloride was dissolved in 54.72g of deionized water to obtain an aqueous solution of lithium chloride. Then, 100g of γ-Al2O3 support was added to the above aqueous solution of lithium chloride and soaked for 60min until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 500℃ for 2h in an air atmosphere to obtain the modified composite oxide support.
[0068] 10g of sodium methoxide was dissolved in 75g of anhydrous methanol solution to obtain anhydrous methanol solution of sodium methoxide; the modified composite oxide support prepared above was immersed in the above anhydrous methanol solution of sodium methoxide for 60min until the solution was completely absorbed and loaded by the support, and then ultrasonically dried at 85℃ for 4h, and calcined in a muffle furnace at 250℃ for 3h under nitrogen atmosphere; thus, a 10% sodium methoxide / 5% Li-γ-Al2O3 catalyst was obtained.
[0069] Example 2
[0070] 12.11g of lithium chloride was dissolved in 72.89g of deionized water to obtain an aqueous solution of lithium chloride. Then, 100g of γ-Al2O3 support was added to the above aqueous solution of lithium chloride and soaked for 30min until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 400℃ for 6h in an air atmosphere to obtain the modified composite oxide support.
[0071] 20g of sodium methoxide was dissolved in 65g of anhydrous methanol solution to obtain anhydrous methanol solution of sodium methoxide; the modified composite oxide support prepared above was immersed in the above anhydrous methanol solution of sodium methoxide for 120min until the solution was completely absorbed and loaded by the support, and then ultrasonically dried at 85℃ for 4h, and calcined in a muffle furnace at 200℃ for 4h under nitrogen atmosphere; thus, a 20% sodium methoxide / 2% Li-γ-Al2O3 catalyst was obtained.
[0072] Example 3
[0073] 10.91g of La(NO3)3·6H2O was weighed and dissolved in 74.09g of deionized water to obtain an aqueous solution of lanthanum nitrate. Then, 100g of γ-Al2O3 support was added to the above aqueous solution of lanthanum nitrate and immersed for 240min until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 700℃ for 2h in an air atmosphere to obtain the modified composite oxide support.
[0074] 15g of potassium methoxide was dissolved in 70g of anhydrous methanol solution to obtain anhydrous methanol solution of potassium methoxide; the modified composite oxide support prepared above was immersed in the above anhydrous methanol solution of potassium methoxide for 120min until the solution was completely absorbed and loaded by the support, and then ultrasonically dried at 85℃ for 4h, and calcined in a muffle furnace at 250℃ for 3h under nitrogen atmosphere; thus, a 15% potassium methoxide / 3.5% La-γ-Al2O3 catalyst was obtained.
[0075] Example 4
[0076] 9.85g of lithium nitrate was dissolved in 75.15g of deionized water to obtain an aqueous solution of lithium nitrate. Then, 100g of γ-Al2O3 support was added to the above aqueous solution of lithium nitrate and soaked for 180min until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 600℃ for 3h in an air atmosphere to obtain the modified composite oxide support.
[0077] 25g of potassium methoxide was dissolved in 60g of anhydrous methanol solution to obtain an anhydrous methanol solution of potassium methoxide; the modified composite oxide support prepared above was immersed in the above anhydrous methanol solution of potassium methoxide for 240min until the solution was completely absorbed and loaded by the support, and then ultrasonically dried at 85℃ for 4h, and calcined in a muffle furnace at 250℃ for 3h under nitrogen atmosphere; thus, a 25% potassium methoxide / 1% Li-γ-Al2O3 catalyst was obtained.
[0078] Example 5
[0079] 10.91g of La(NO3)3·6H2O was weighed and dissolved in 74.09g of deionized water to obtain an aqueous solution of lanthanum nitrate. Then, 100g of γ-Al2O3 support was added to the above aqueous solution of lanthanum nitrate and immersed for 240min until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 700℃ for 2h in an air atmosphere to obtain the modified composite oxide support.
[0080] 5g of potassium methoxide was dissolved in 80g of anhydrous methanol solution to obtain an anhydrous methanol solution of potassium methoxide. The modified composite oxide support prepared above was immersed in the above anhydrous methanol solution of potassium methoxide for 30 minutes until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85℃ for 4 hours and calcined in a muffle furnace at 200℃ for 3 hours under a nitrogen atmosphere. The sample with one loading was obtained.
[0081] 25g of sodium methoxide was weighed again and dissolved in 60g of anhydrous methanol solution to obtain anhydrous methanol solution of sodium methoxide. The sample prepared above and loaded once was immersed in the above anhydrous methanol solution of sodium methoxide for 240min until the solution was completely absorbed and loaded by the support. Then it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 150℃ for 4h under nitrogen atmosphere to obtain 25% sodium methoxide-5% potassium methoxide / 3.5% La-γ-Al2O3 catalyst.
[0082] Example 6
[0083] 37.39 g of Mg(NO3)2·6H2O was weighed and dissolved in 47.61 g of deionized water to obtain an aqueous solution of magnesium nitrate; then 100 g of γ-Al2O3 support was added to the above aqueous solution of magnesium nitrate and soaked for 180 min until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85 °C for 4 h and calcined in a muffle furnace at 600 °C for 3 h in an air atmosphere to obtain the modified composite oxide support.
[0084] 10g of potassium methoxide was dissolved in 75g of anhydrous methanol solution to obtain an anhydrous methanol solution of potassium methoxide. The modified composite oxide support prepared above was immersed in the anhydrous methanol solution of potassium methoxide for 30 minutes until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85℃ for 4 hours and calcined in a muffle furnace at 200℃ for 3 hours under a nitrogen atmosphere. The sample with one loading was obtained.
[0085] 15g of sodium methoxide was weighed again and dissolved in 70g of anhydrous methanol solution to obtain anhydrous methanol solution of sodium methoxide. The sample prepared above and loaded once was immersed in the above anhydrous methanol solution of sodium methoxide for 60min until the solution was completely absorbed and loaded by the support. Then it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 200℃ for 3h under nitrogen atmosphere to obtain 20% sodium methoxide-10% potassium methoxide / 3.5% Mg-γ-Al2O3 catalyst.
[0086] Example 7
[0087] 12.11g of lithium chloride was dissolved in 72.89g of deionized water to obtain an aqueous solution of lithium chloride. Then, 100g of γ-Al2O3 support was added to the above aqueous solution of lithium chloride and soaked for 60min until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 600℃ for 5h in an air atmosphere to obtain the modified composite oxide support.
[0088] 5g of potassium tert-butoxide was dissolved in 80g of anhydrous methanol solution to obtain an anhydrous methanol solution of potassium tert-butoxide. The modified composite oxide support prepared above was immersed in the above anhydrous methanol solution of potassium tert-butoxide for 60min until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 150℃ for 3h under a nitrogen atmosphere. The sample with one loading was obtained.
[0089] 20g of sodium methoxide was weighed again and dissolved in 65g of anhydrous methanol solution to obtain anhydrous methanol solution of sodium methoxide. The sample prepared above and loaded once was immersed in the above anhydrous methanol solution of sodium methoxide for 60min until the solution was completely absorbed and loaded by the support. Then it was ultrasonically dried at 85℃ for 4h and calcined in a muffle furnace at 200℃ for 4h under nitrogen atmosphere to obtain 20% sodium methoxide-5% potassium tert-butoxide / 2% Li-γ-Al2O3 catalyst.
[0090] Example 8
[0091] The performance of the catalyst prepared in Example 1 in the decarbonylation reaction of methyl formate was evaluated using a fixed-bed reactor. The reactor had an inner diameter of 10 mm, was equipped with thermocouple sheaths, and had a catalyst loading of 5 ml. The feed liquid was preheated and passed from top to bottom through the catalyst bed. The reaction products were condensed and separated into liquid methanol and gaseous carbon monoxide. The feed liquid was methyl formate or a mixture of methyl formate and methanol, with methanol comprising 45% of the methyl formate by weight. The reaction temperature was controlled at 240 °C, the reaction pressure at 0.7 MPa, and the liquid hourly space velocity (LHSV) at 2 h⁻¹. -1 .
[0092] Example 9
[0093] The performance of the catalyst prepared in Example 2 in the decarbonylation reaction of methyl formate was evaluated using a fixed-bed reactor. The reactor had an inner diameter of 10 mm, was equipped with thermocouple sheaths, and had a catalyst loading of 5 ml. The feed liquid was preheated and passed from top to bottom through the catalyst bed. The reaction products were condensed and separated into liquid methanol and gaseous carbon monoxide. The feed liquid was methyl formate or a mixture of methyl formate and methanol, with methanol comprising 25% by weight of methyl formate. The reaction temperature was controlled at 220 °C, the reaction pressure at 0.9 MPa, and the liquid hourly space velocity (LHSV) at 3 h⁻¹. -1 .
[0094] Example 10
[0095] The performance of the catalyst prepared in Example 5 in the decarbonylation reaction of methyl formate was evaluated using a fixed-bed reactor. The reactor had an inner diameter of 10 mm, was equipped with thermocouple sheaths, and had a catalyst loading of 5 ml. The feed liquid was preheated and passed from top to bottom through the catalyst bed. The reaction products were condensed and separated into liquid methanol and gaseous carbon monoxide. The feed liquid was methyl formate or a mixture of methyl formate and methanol, with methanol comprising 65% of the methyl formate by weight. The reaction temperature was controlled at 260 °C, the reaction pressure at 0.4 MPa, and the liquid hourly space velocity (LHSV) at 1 h⁻¹. -1 .
[0096] Comparative Example 1
[0097] 30.28 g of lithium chloride was dissolved in 54.72 g of deionized water to obtain an aqueous solution of lithium chloride. 100 g of γ-Al2O3 support was added to the above aqueous solution of lithium chloride and impregnated for 240 min until the solution was completely absorbed and loaded by the support. Then, it was ultrasonically dried at 85 °C for 4 h and calcined in a muffle furnace at 600 °C for 3 h to obtain a 3.5% Li-γ-Al2O3 catalyst.
[0098] Comparative Example 2
[0099] 20g of sodium methoxide was dissolved in 65g of anhydrous methanol solution to obtain anhydrous methanol solution of sodium methoxide; 100g of γ-Al2O3 support was added to the above anhydrous methanol solution of sodium methoxide and impregnated for 240min until the solution was completely absorbed and loaded by the support, then ultrasonically dried at 85℃ for 4h, and calcined in a muffle furnace at 200℃ for 4h to obtain 20% sodium methoxide / γ-Al2O3 catalyst.
[0100] Comparison Test Example 1
[0101] The performance of the catalysts prepared in Examples 1-7 and Comparative Examples 1-2 in the decarbonylation reaction of methyl formate was evaluated using a fixed-bed reactor. The reactor had an inner diameter of 10 mm, was equipped with thermocouple sheaths, and had a catalyst loading of 5 ml. The feed liquid was preheated and passed from top to bottom through the catalyst bed. The reaction products were condensed and separated into liquid methanol and gaseous carbon monoxide. The feed liquid was methyl formate or a mixture of methyl formate and methanol, with methanol comprising 45% of the methyl formate by weight. The reaction temperature was controlled at 240 °C, the reaction pressure at 0.7 MPa, and the liquid hourly space velocity (LHSV) at 2 h⁻¹. -1 .
[0102] The conversion rates of methyl formate and the selectivity of methanol and CO obtained by the catalysts prepared in Examples 1-7 and Comparative Examples 1-2 in the decarbonylation reaction of methyl formate to produce methanol and CO are shown in Table 1 below.
[0103] Table 1
[0104] catalyst Methyl formate conversion rate, % Methanol selectivity, % CO selectivity, % Example 1 88.5 98.3 97.1 Example 2 98.3 98.5 99.0 Example 3 98.5 98.9 99.3 Example 4 97.6 99.1 98.7 Example 5 99.8 99.7 99.6 Example 6 99.1 99.6 99.3 Example 7 98.5 99.3 99.5 Comparative Example 1 22.4 87.6 76.8 Comparative Example 2 62.8 94.5 85.2
[0105] As shown in Table 1, compared with the catalysts prepared in Comparative Examples 1-2, the catalysts prepared by this method as in Examples 1-7 are simple to prepare and have good reactivity in the decarbonylation reaction of methyl formate. When used in a gas-solid phase system to realize the decarbonylation reaction of methyl formate, the conversion rate and selectivity are excellent, reaching more than 88% or even close to 100% methyl formate conversion rate, higher than 98% methanol selectivity, and higher than 97% CO selectivity.
[0106] Comparison Test Example 2
[0107] The catalyst prepared in Example 5 was used in the decarbonylation reaction of methyl formate according to Comparative Test Example 1, and its stability was investigated. The test results are shown in [Figure 1]. Figure 1 .Depend on Figure 1 It can be seen that the catalyst prepared in Example 5 did not show catalyst deactivation after 1000 hours of reaction, and the methyl formate conversion rate (see...) Figure 1 The MF conversion rate remained above 97% after the reaction induction period, and the selectivity of methanol (see...) Figure 1 The selectivity of the catalyst (Me) remained above 99%, indicating that the catalyst has good stability and is ready for industrial application.
[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.
Claims
1. A catalyst comprising a modified composite alumina support loaded with an alkali metal active component, conforming to the general chemical formula: M1 / M2-γ-Al2O3, wherein, M1 is the alkali metal active component, M2 is the modifying agent, and M2-γ-Al2O3 is the M2-modified composite alumina carrier.
2. The catalyst according to claim 1, characterized in that, The alkali metal active component is an alkali metal organic salt; preferably, the alkali metal active component is selected from one or more combinations of sodium methoxide, potassium methoxide, or potassium tert-butoxide.
3. The catalyst according to claim 1, characterized in that, The modifying agent is selected from one or more combinations of soluble salts of lithium, magnesium, or lanthanum; preferably, the soluble salts of lithium, magnesium, or lanthanum are selected from at least one of chloride, nitrate, or acetate.
4. The catalyst according to claim 1, characterized in that, The loading amount of M1 on the alumina support is 10-30 wt%; and / or, the loading amount of M2 on the alumina support is 1-5 wt%.
5. A method for preparing the catalyst according to any one of claims 1-4, comprising the following steps: 1) Carrier modification: The alumina carrier is impregnated in an aqueous solution of the modifying agent by an equal volume impregnation method, followed by drying and calcination to provide a modified composite alumina carrier. 2) Loading of alkali metal active components: The modified composite alumina support obtained in step 1) is impregnated in an alcohol solution of alkali metal active components at least once using the equal volume impregnation method, followed by drying and calcination, to provide the required catalyst.
6. The method for preparing the catalyst according to claim 5, characterized in that, Step 1) includes one or more of the following conditions: A1) The modifying agent is selected from one or more combinations of soluble salts of lithium, magnesium or lanthanum; preferably, the soluble salt of lithium, magnesium or lanthanum is selected from at least one of chloride, nitrate or acetate. A2) The concentration of the metal element in the aqueous solution of the modified additive is 1.18-5.88 wt%; A3) The soaking time is 0.5-4 hours; A4) The drying temperature is 80-90℃; A5) The drying time is 3-5 hours; A6) The roasting is carried out in an air atmosphere; A7) The roasting temperature is 400-700℃; The roasting time described in A8) is 2-6 hours.
7. The method for preparing the catalyst according to claim 5, characterized in that, Step 2) includes one or more of the following conditions: B1) The alkali metal active component is an alkali metal organic salt; preferably, the alkali metal active component is selected from one or more combinations of sodium methoxide, potassium methoxide, or potassium tert-butoxide. B2) The alcohol in the alcohol solution of the alkali metal active component is anhydrous methanol; B3) The concentration of the alkali metal active component in the alcohol solution is 5.88-29.41 wt%. B4) The soaking time is 0.5-4 hours; B5) The drying temperature is 80-90℃; B6) The drying time is 3-5 hours; B7) The roasting is carried out under a nitrogen atmosphere; B8) The roasting temperature is 150-250℃; B9) The roasting time is 2-4 hours; The alkali metal active component described in B10 is loaded 1-2 times.
8. Use of the catalyst according to any one of claims 1-4 in the decarbonylation reaction of methyl formate to prepare methanol and carbon monoxide.
9. A method for preparing methanol and carbon monoxide by decarbonylation reaction of methyl formate, comprising: Methyl formate or a mixture of methyl formate and methanol is subjected to a decarbonylation reaction under the action of a catalyst according to any one of claims 1-4. After condensation, the gas and liquid phases are separated to obtain methanol in liquid phase and carbon monoxide in gas phase, respectively.
10. The method for preparing methanol and carbon monoxide by the decarbonylation reaction of methyl formate according to claim 9, characterized in that, Includes one or more of the following conditions: C1) The weight percentage of methanol in the mixture of methyl formate and methanol is >0 and ≤70%; The decarbonylation reaction described in C2) takes place at a temperature of 200-280℃; The reaction pressure for the decarbonylation reaction described in C3) is 0.3-1.0 MPa; C4) The liquid space velocity of the feedstock for the decarbonylation reaction is 1-3 h⁻¹. -1 .