Catalyst for preparing high-purity CO and methanol by cracking formate and preparation method of catalyst

Abstract

The invention relates to a catalyst for preparing high-purity CO and methanol by cracking formate and a preparation method thereof, the catalyst comprises a carrier and active components loaded on the carrier, the active components comprise alkali metal and group VIII metal, and the carrier adopts alumina. The preparation method of the catalyst comprises the following steps: directly mixing a solution obtained by dissolving the active component, a nonionic surfactant solution and the carrier, uniformly stirring, kneading, extruding into strips, forming, drying and roasting to obtain the catalyst. The active components are introduced in the catalyst forming stage, and the secondary impregnation step is omitted. By adding the surfactant, on one hand, dispersion of the active components on the carrier can be improved, and on the other hand, gas generated during roasting can improve the pore structure of the catalyst, so that the reaction performance of the catalyst is improved; in addition, the surfactant can occupy part of the active center to prevent formate from cracking and carbon deposition, and the service life of the catalyst is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology and relates to a catalyst for the cracking of formate esters to produce high-purity CO and methanol and its preparation method. Background Technology

[0002] In the syngas-to-ethylene glycol process, a small amount of methyl formate is produced as a byproduct of the esterification and carbonylation stages. During its circulation and accumulation within the system, it reacts with water, hydrolyzing to form formic acid, which corrodes equipment. Current treatment methods primarily involve distillation to concentrate the formate before incineration, or purification to a higher purity for sale as a byproduct. However, incineration is wasteful of resources and results in high carbon emissions. Selling it as a byproduct requires increasing the concentration, which is energy-intensive. Furthermore, methyl formate has a low boiling point, is highly hazardous, has a limited transportation radius, and is difficult to sell. Therefore, decarbonylating methyl formate to produce high-value-added methanol and CO can achieve effective resource utilization and recycling.

[0003] The prior art CN202011031652.3 discloses a method for the decarbonylation of methyl formate to produce high-purity methanol and CO. Specifically, it provides a technical solution for decomposing purified methyl formate into carbon monoxide and methanol under the action of a catalyst. The catalyst used in this technical solution has a high content of active components and active additives, resulting in high catalyst cost, complex preparation process, and poor catalyst life and activity. Summary of the Invention

[0004] The purpose of this invention is to provide a catalyst and its preparation method for the cracking of formate esters to produce high-purity CO and methanol. By improving the preparation process and introducing a nonionic surfactant, the problems of high cost, complex preparation methods, and low catalyst activity and lifespan of existing catalysts and their preparation methods for the cracking of formate esters to produce high-purity CO and methanol are solved.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A first aspect of the present invention provides a catalyst for the pyrolysis of formate esters to produce high-purity CO and methanol, comprising:

[0007] The mixture of methyl formate from the ethylene glycol ester chemical section was distilled to obtain purified methyl formate material.

[0008] Methyl formate is cracked in the presence of a catalyst to produce CO and methanol;

[0009] The catalyst includes a support and an active component supported on the support;

[0010] The active component includes:

[0011] Active component one is selected from one or more alkali metals;

[0012] Active component two is selected from one or more Group VIII metals;

[0013] The carrier is aluminum oxide.

[0014] The alkali metal in active component one effectively activates the C=O bond of methyl formate, significantly reducing the activation energy of the cracking reaction. The Group VIII metal in active component two exhibits a synergistic catalytic effect with the alkali metal, increasing the catalyst's reactivity. The alumina support provides a high specific surface area and stability for both the alkali metal and the Group VIII metal, ensuring a high degree of dispersion of active sites. This synergistic catalyst system achieves highly selective cracking of methyl formate into CO and methanol, improving both reaction performance and economic efficiency.

[0015] In some specific embodiments, the first active component is selected from one or more of Li, Na, K, and Rb, and the second active component is selected from one or more of Fe, Co, Ni, Ru, Pt, and Pd.

[0016] In some specific embodiments, the loading of active component one relative to the carrier is 3-10 wt% by elemental mass; preferably 5-10 wt%; and the loading of active component two relative to the carrier is 0.05-2 wt%; preferably 0.05-1 wt%.

[0017] A second aspect of the present invention provides a method for preparing a catalyst for the cracking of formate esters to produce high-purity CO and methanol, comprising the following steps:

[0018] (1) Weigh out soluble active component one and active component two according to the mass ratio, add deionized water and stir to dissolve, to obtain impregnation solution A;

[0019] (2) Weigh the nonionic surfactant according to the mass ratio, add deionized water to dissolve it, and obtain solution B;

[0020] (3) Weigh alumina according to the mass ratio, add impregnation solution A and solution B respectively, stir evenly, knead and extrude into strips to obtain catalyst precursor;

[0021] (4) The obtained catalyst precursor is dried and calcined to obtain the catalyst.

[0022] Alkali metals are highly basic and have high decarbonylation activity, but they are also prone to deep decarbonylation, producing H2 or carbon deposits. This application uses surfactants to improve the dispersion of active components on alumina supports and pre-deposit carbon to occupy a small number of basic centers in order to reduce carbon deposits, maintain the activity and selectivity of active components, and have higher economic efficiency.

[0023] In some specific embodiments, the soluble active component of step (1) is its nitrate, acetate, carbonate or halide.

[0024] In some specific embodiments, the nonionic surfactant in step (2) is selected from one or more of polyethylene glycol (PEG2000-PEG20000), polyvinylpyrrolidone, and polyacrylamide.

[0025] In some specific embodiments, the alumina precursor in step (3) is one of boehmite, boehmite, aluminum hydroxide, or amorphous alumina powder.

[0026] In some specific embodiments, the amount of surfactant used is 0.1-2% of the mass of the alumina precursor, preferably 0.5-1%.

[0027] In some specific embodiments, the drying temperature of step (4) is 80-120℃ and the drying time is 6-12h; the calcination temperature is 350-550℃ and the calcination time is 3-6h.

[0028] A third aspect of the present invention provides an application of a catalyst for the pyrolysis of formate to produce high-purity CO and methanol. The catalyst is used in a fixed-bed reactor for the pyrolysis of formate to produce CO and methanol. Before use, the catalyst needs to be heated to 200-250°C in an atmosphere of N2 or CO and kept at that temperature for at least 4 hours.

[0029] The catalyst is used under the following conditions: reaction temperature of 190-240℃, reaction pressure of atmospheric pressure -5 bar, and mass hourly space velocity of the feed formate ester of 0.5-5 g / gcat.h.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention uses active component one selected from alkali metals and active component two selected from group VIII metals as active components, and uses alumina as a support. The resulting catalyst system has higher catalyst activity and selectivity, with MF conversion rate up to 99.8% and ME selectivity up to 99.5%.

[0032] 2. In the catalyst preparation stage of this invention, active component one and active component two are introduced during the catalyst forming stage, reducing the secondary impregnation step and simplifying the catalyst preparation process. Introducing nonionic surfactants into the catalyst preparation process has three significant advantages: 1) It can improve the dispersion of active components on the support, further enhancing catalyst activity; 2) During calcination, the surfactant decomposes upon heating, generating a certain amount of gas, which can create a certain amount of pores and cavities on the support, reducing the diffusion resistance of reactants on the catalyst and improving catalyst reaction performance; 3) During calcination, some surfactants do not completely burn, and after cracking and carbonylation, they occupy some basic active centers, which can inhibit carbon deposition from deep cracking of formate esters, thereby extending catalyst life.

[0033] 3. The catalyst used in this invention has high catalytic cracking activity and selectivity for MF. Alkali metals are strongly alkaline and have high decarbonylation activity, but they are also prone to deep decarbonylation, producing H2 or carbon deposits. This application uses a surfactant to improve the dispersion of the active component on the alumina support and pre-deposit carbon to occupy a small number of alkaline centers to reduce carbon deposits and maintain the activity of the active component. This can significantly improve the selectivity of ME and is more economical than traditional methods. Detailed Implementation

[0034] The present invention will now be described in detail with reference to specific embodiments.

[0035] A catalyst for the cracking of formate esters to produce high-purity CO and methanol, comprising:

[0036] The mixture of methyl formate from the ethylene glycol ester chemical section was distilled to obtain purified methyl formate material.

[0037] Methyl formate is cracked in the presence of a catalyst to produce CO and methanol;

[0038] The catalyst includes a support and an active component supported on the support;

[0039] The active component includes:

[0040] Active component one is selected from one or more alkali metals;

[0041] Active component two is selected from one or more Group VIII metals;

[0042] The carrier is aluminum oxide.

[0043] A method for preparing a catalyst for the cracking of formate esters to produce high-purity CO and methanol includes the following steps:

[0044] (1) Weigh out soluble active component one and active component two according to the mass ratio, add deionized water and stir to dissolve, to obtain impregnation solution A;

[0045] (2) Weigh the nonionic surfactant according to the mass ratio, add deionized water to dissolve it, and obtain solution B;

[0046] (3) Weigh alumina according to the mass ratio, add impregnation solution A and solution B respectively, stir evenly, knead and extrude into strips to obtain catalyst precursor;

[0047] (4) The obtained catalyst precursor is dried and calcined to obtain the catalyst.

[0048] Application of a catalyst for the cracking of formate to produce high-purity CO and methanol, wherein the catalyst is used in a fixed-bed reactor for the cracking of formate to produce CO and methanol, and the catalyst needs to be heated to 200-250°C and maintained for not less than 4 hours under an atmosphere of N2 or CO before use;

[0049] The catalyst is used under the following conditions: reaction temperature of 190-240℃, reaction pressure of atmospheric pressure -5 bar, and mass hourly space velocity of the feed formate ester of 0.5-5 g / gcat.h.

[0050] This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiment.

[0051] In the following embodiments, unless otherwise specified, the raw materials, reagents or processing techniques are all conventional commercial products or conventional processing techniques in the art.

[0052] Example 1:

[0053] Weigh 36.95g of sodium nitrate and 7.21g of ferric nitrate nonahydrate, and dissolve them in 50g of deionized water; weigh 0.5g of polyethylene glycol (PEG20000) and dissolve it in 10g of deionized water; weigh 100g of boehmite, mix the two aqueous solutions separately, stir evenly, knead and extrude to obtain the catalyst precursor.

[0054] The catalyst precursor was dried in an oven at 120°C for 6 hours and then calcined in a muffle furnace at 500°C for 5 hours to obtain the catalyst 10Na1Fe-100Al2O3.

[0055] The catalyst was heated to 240°C under a N2 atmosphere and held for 6 h, then cooled to 210°C, with a mass hourly space velocity (MF) of 0.5 h⁻¹. -1 MF conversion rate 99.8%, ME selectivity 99.5%.

[0056] Example 2:

[0057] Weigh 5.19g of rubidium nitrate and 9.91g of sodium nitrate hexahydrate, add 40g of deionized water and stir to dissolve; weigh 2g of polyvinylpyrrolidone and add 20g of deionized water and stir to dissolve; weigh 100g of boehmite, and mix the two aqueous solutions separately, stir evenly, knead and extrude to obtain the catalyst precursor.

[0058] The catalyst precursor was dried in an oven at 100℃ for 12 hours and then calcined in a muffle furnace at 350℃ for 6 hours to obtain the catalyst 3Rb2Ni-100Al2O3.

[0059] The catalyst was heated to 200℃ and held for 8 hours under a N2 atmosphere, then cooled to 240℃. The MF mass hourly space velocity was 5 h⁻¹, the MF conversion was 98.6%, and the ME selectivity was 99.3%.

[0060] Example 3:

[0061] Weigh 26.77g of lithium carbonate and 0.143g of palladium nitrate aqueous solution (palladium concentration of palladium nitrate aqueous solution is 35%), add 40g of deionized water and stir to dissolve; weigh 1g of polyacrylamide and add 20g of deionized water and stir to dissolve; weigh 100g of aluminum hydroxide powder, and mix the two aqueous solutions separately, stir evenly, knead and extrude to obtain the catalyst precursor.

[0062] The catalyst precursor was dried in an oven at 80°C for 12 hours and then calcined in a muffle furnace at 450°C for 4 hours to obtain the catalyst 5Li0.05Pd-100Al2O3.

[0063] The catalyst was heated to 250℃ and held for 4 h in a N2 atmosphere, then cooled to 210℃. The MF mass hourly space velocity was 2 h⁻¹, the MF conversion was 99.1%, and the ME selectivity was 99.2%.

[0064] Example 4:

[0065] Weigh 20.74g potassium nitrate and 1.03g ruthenium trichloride, add 55g deionized water and stir to dissolve; weigh 0.1g polyethylene glycol 2000 and add 5g deionized water and stir to dissolve; weigh 100g amorphous alumina powder, and mix the two aqueous solutions separately, stir evenly, knead and extrude to obtain the catalyst precursor.

[0066] The catalyst precursor was dried in an oven at 120°C for 8 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain the catalyst 8K0.5Ru-100Al2O3.

[0067] The catalyst was heated to 220℃ and held for 6 h in a CO atmosphere, then cooled to 190℃. The mass hourly space velocity (MHSV) of the catalyst was 1 h⁻¹, the MF conversion was 99%, and the ME selectivity was 99.5%.

[0068] Example 5:

[0069] Weigh 15.55g of potassium nitrate and 7.41g of cobalt nitrate hexahydrate, add 50g of deionized water and stir to dissolve; weigh 0.5g of polyethylene glycol 10000 and add 10g of deionized water and stir to dissolve; weigh 100g of boehmite powder, and mix the two aqueous solutions separately, stir evenly, knead and extrude to obtain the catalyst precursor.

[0070] The catalyst precursor was dried in an oven at 120°C for 12 hours and then calcined in a muffle furnace at 400°C for 5 hours to obtain the catalyst 6K1.5Co-100Al2O3.

[0071] The catalyst was heated to 240℃ and held for 4 h in a CO atmosphere, then cooled to 205℃. The MF mass hourly space velocity was 1 h⁻¹, the MF conversion was 98.3%, and the ME selectivity was 99.1%.

[0072] Example 6:

[0073] Weigh 6.75g of rubidium carbonate and 0.21g of chloroplatinic acid, add 50g of deionized water and stir to dissolve; weigh 1g of polyvinylpyrrolidone, add 10g of deionized water and stir to dissolve; weigh 100g of boehmite, and mix the two aqueous solutions separately, stir evenly, knead and extrude to obtain the catalyst precursor.

[0074] The catalyst precursor was dried in an oven at 120°C for 12 hours and then calcined in a muffle furnace at 400°C for 5 hours to obtain the catalyst 5Rb0.1Pt-100Al2O3.

[0075] The catalyst was heated to 240℃ and held for 5 h under a CO atmosphere, then cooled to 210℃. With an MF mass hourly space velocity of 2 h⁻¹, the MF conversion was 98.1%, and the ME selectivity was 99.3%.

[0076] Comparative Example 1:

[0077] Weigh 36.95g of sodium nitrate and 7.21g of ferric nitrate nonahydrate, add 60g of deionized water to dissolve them; weigh 100g of boehmite, mix the above aqueous solution into it, stir evenly, knead and extrude to obtain the catalyst precursor.

[0078] The catalyst precursor was dried in an oven at 120°C for 6 hours and then calcined in a muffle furnace at 500°C for 5 hours to obtain the catalyst 10Na1Fe-100Al2O3.

[0079] The catalyst was heated to 240℃ under N2 atmosphere and held for 6 h, then cooled to 210℃. The MF mass hourly space velocity was 0.5 h⁻¹, the MF conversion was 99.3%, and the ME selectivity was 95.2%.

[0080] Comparative Example 2:

[0081] Weigh 36.95g of sodium nitrate and dissolve it in 60g of deionized water; weigh 100g of boehmite, mix it with the above aqueous solution, stir evenly, knead and extrude to obtain the catalyst precursor.

[0082] The catalyst precursor was dried in an oven at 120°C for 6 hours and then calcined in a muffle furnace at 500°C for 5 hours to obtain the catalyst Na-Al2O3.

[0083] The catalyst was heated to 240℃ under N2 atmosphere and held for 6 h, then cooled to 210℃. The MF mass hourly space velocity was 0.5 h⁻¹, the MF conversion was 94.2%, and the ME selectivity was 95.7%.

[0084] As can be seen from Example 1 and Comparative Example 1, the catalyst without the addition of nonionic surfactant during catalyst preparation showed a significant decrease in the selectivity of ME and a decrease in the conversion rate of MF. This is because the nonionic surfactant promotes a more uniform dispersion of the two active components on the support, the basic active sites on the catalyst surface are more uniform and less concentrated, and the small amount of carbon deposits generated by the decomposition of the surfactant occupy some of the basic sites, reducing deep decarbonylation and significantly improving the selectivity of ME. Therefore, the lack of addition of nonionic surfactant leads to a significant decrease in the selectivity of ME.

[0085] As can be seen from Comparative Examples 1 and 2, the catalyst activity without the addition of active component 2 is significantly reduced, the conversion rate of MF is only 94.2%, and the selectivity of ME is almost unchanged. This indicates that the catalyst composition claimed in this application has a significant synergistic effect and can significantly improve the conversion rate of MF.

[0086] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A catalyst for the cracking of formate esters to produce high-purity CO and methanol, characterized in that, include: The mixture of methyl formate from the ethylene glycol ester chemical section was distilled to obtain purified methyl formate material. Methyl formate is cracked in the presence of a catalyst to produce CO and methanol; The catalyst includes a support and an active component supported on the support; The active component includes: Active component one is selected from one or more alkali metals; Active component two is selected from one or more Group VIII metals; The carrier is aluminum oxide.

2. The catalyst for the preparation of high-purity CO and methanol by formate ester cracking according to claim 1, characterized in that, The first active component is selected from one or more of Li, Na, K, and Rb, and the second active component is selected from one or more of Fe, Co, Ni, Ru, Pt, and Pd.

3. The catalyst for the preparation of high-purity CO and methanol by formate ester cracking according to claim 2, characterized in that, The loading of active component one relative to the carrier is 3-10 wt% by elemental mass; preferably 5-10 wt%; and the loading of active component two relative to the carrier is 0.05-2 wt%; preferably 0.05-1 wt%.

4. The catalyst for the production of high-purity CO and methanol by formate ester cracking according to any one of claims 1-3, characterized in that, The method for preparing the catalyst includes the following steps: (1) Weigh out soluble active component one and active component two according to the mass ratio, add deionized water and stir to dissolve, to obtain impregnation solution A; (2) Weigh the nonionic surfactant according to the mass ratio, add deionized water to dissolve it, and obtain solution B; (3) Weigh alumina according to the mass ratio, add impregnation solution A and solution B respectively, stir evenly, knead and extrude into strips to obtain catalyst precursor; (4) The obtained catalyst precursor is dried and calcined to obtain the catalyst.

5. The method for preparing the catalyst for the cracking of formate esters to produce high-purity CO and methanol according to claim 4, characterized in that, The soluble active component in step (1) is its nitrate, acetate, carbonate or halide.

6. The method for preparing the catalyst for the cracking of formate esters to produce high-purity CO and methanol according to claim 4, characterized in that, The nonionic surfactant used in step (2) is selected from one or more of polyethylene glycol (PEG2000-PEG20000), polyvinylpyrrolidone, and polyacrylamide.

7. The method for preparing the catalyst for the cracking of formate esters to produce high-purity CO and methanol according to claim 6, characterized in that, The alumina precursor in step (3) is one of boehmite, boehmite, aluminum hydroxide, or amorphous alumina powder.

8. The method for preparing the catalyst for the cracking of formate esters to produce high-purity CO and methanol according to claim 7, characterized in that, The amount of surfactant used is 0.1-2% of the mass of the alumina precursor, preferably 0.5-1%.

9. The method for preparing the catalyst for the cracking of formate esters to produce high-purity CO and methanol according to claim 4, characterized in that, The drying temperature in step (4) is 80-120℃ and the drying time is 6-12h; the calcination temperature is 350-550℃ and the calcination time is 3-6h.

10. The catalyst for the preparation of high-purity CO and methanol by formate ester cracking according to claim 1, characterized in that, The catalyst is used in a fixed-bed reactor for the cracking of formate to produce CO and methanol. Before use, the catalyst needs to be heated to 200-250°C in an atmosphere of N2 or CO and kept at that temperature for at least 4 hours. The catalyst is used under the following conditions: reaction temperature of 190-240℃, reaction pressure of atmospheric pressure -5 bar, and mass hourly space velocity of the feed formate ester of 0.5-5 g / gcat.h.