Bimetallic solid base catalyst for preparing methyl 2-furyl propionate by esterification of isobutyraldehyde and furfuryl alcohol and its application
By preparing Au-Pd/MgO-Al2O3 bimetallic solid base catalyst, the pollution and difficulty in recycling caused by liquid base catalysts in the prior art are solved, and efficient preparation of 2-methylpropionate-2-furanyl methyl ester is achieved, with good stability and catalytic activity.
Patent Information
- Application Number
- CN202211694664.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-28
- Publication Date
- 2025-06-27
- Estimated Expiration
- 2042-12-28
AI Technical Summary
In the prior art, when preparing catalysts of 2-methylpropionate-2-furanyl methyl ester, there are problems such as high pollution, high corrosion, difficulty in separation, and difficulty in recycling caused by liquid alkali catalysts.
The bimetal solid base catalyst for 2-methylpropionate 2-methylpropionate-2-furanyl methyl ester is prepared by esterification of isobutyraldehyde and furfuryl alcohol. By uniformly dispersing the oxidized gold hydrate and sodium hydroxide solution with sodium dodecylbenzene sulfonate and other substances, an Au-Pd/MgO-Al2O3 bimetal solid base catalyst is formed, and calcined and reduced under specific conditions to improve the stability and catalytic activity of the catalyst.
The efficient preparation of 2-methylpropionate-2-furanyl methyl ester was achieved, solving the problems of contamination and difficulty in recycling of liquid base catalysts. The catalyst has good stability and catalytic activity, simplifying the process flow, and improving yield and selectivity.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of catalyst preparation, and particularly relates to a bimetallic solid base catalyst for the esterification of isobutyraldehyde and furfuryl alcohol to prepare 2-furylmethyl 2-methylpropionate and its application. Background Art
[0002] At present, thousands of plasticizers have been developed and produced in the world, and more than a hundred varieties have been applied industrially. Plastic additives that do not meet the requirements of health and environmental protection will be gradually phased out, such as certain plasticizers containing harmful substances such as lead and halogens. With the continuous progress of technology and the upgrading of the industrial structure, in recent years, plasticizers have shown a development trend of being non-toxic and green. Among them, bio-based plasticizers extracted from biological resources, with biodegradability and excellent plasticization performance, are considered an important development direction of plasticizers.
[0003] As an important part of biomass plasticizers, 2-furylmethyl 2-methylpropionate is an ideal product to replace traditional phthalate plasticizers. Bio-based plasticizers have wide sources, simple synthesis methods, high stability, can be recycled, and are non-toxic to humans and pollution-free to the environment. From the perspectives of economy, environmental protection, and health, the competitive advantages of bio-based plasticizers are becoming more and more obvious. Especially this year, with the recovery of crude oil prices, the cost of petroleum-based plasticizers has increased with the rise of crude oil prices, and the cost advantages of bio-based plasticizers have gradually emerged. 2-Furylmethyl 2-methylpropionate has properties such as adjusting the viscosity, crystallinity, hardness, flexibility, fracture resistance, dielectric constant, and fire resistance of polymer materials. At the same time, 2-furylmethyl 2-methylpropionate is insoluble in water, has a specific gravity close to that of water, and has good compatibility with plastic molecules. The two are mainly combined by hydrogen bonds or van der Waals forces, and each maintains relatively independent chemical properties. The 2-furylmethyl 2-methylpropionate biomass plasticizer is produced by processing renewable biomass resources. Therefore, the development of bio-based plasticizers is an important direction for the future plasticizer industry. Summary of the Invention
[0004] The purpose of the present invention is to develop a bimetallic solid base catalyst for the esterification of isobutyraldehyde and furfuryl alcohol to prepare 2-furylmethyl 2-methylpropionate and its application.
[0005] To achieve the above purpose, the technical solution adopted by the present invention is:
[0006] A bimetallic solid base for the esterification of isobutyraldehyde and furfuryl alcohol to prepare 2-furylmethyl 2-methylpropionate, and the preparation steps are as follows:
[0007] (1) Dissolve gold hydroxide hydrate and / or gold oxide and / or silver oxide in sodium hydroxide solution, disperse evenly, add sodium dodecylbenzenesulfonate (SDBS, which acts as a template agent to make the prepared catalyst have a good crystalline morphology, high specific surface area, stable structure, and contribute to the diffusion of reactant molecules), and obtain solution A after uniform dispersion; dissolve magnesium chloride, aluminum chloride, and palladium chloride in deionized water, and stir evenly to obtain solution B;
[0008] To ensure the synthesis of a stable hydrotalcite layered structure catalyst, the relevant material molar ratios are: n(Mg):n(Al) = 3:1, n(NaOH):n(Al) = 1:1, n(Au):n(Pd) = 1:2;
[0009] Furthermore, m(SDBS) = 1.00 g;
[0010] (2) Under the conditions of a water bath at 59 - 61 °C and strong stirring, slowly drip solution A into solution B, continue stirring for 2.5 - 3.5 h, and stand for aging at room temperature for 23.5 - 24.5 h to ensure more sufficient reaction and improve the catalyst yield. Then filter, wash with deionized water until neutral (pH = 7), and vacuum dry the filter cake (preferably vacuum dry at 30 - 120 °C for 12 - 24 h) to obtain the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst precursor.
[0011] (3) Calcinate the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst precursor at 300 - 500 °C (preferably 450 - 500 °C) for 3 - 10 h to obtain the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst.
[0012] The application of the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst prepared based on the above method includes the following steps: load the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst into a fixed-bed reactor, and fully reduce it with hydrogen (preferably the reduction conditions are to control the hydrogen flow rate at 40 mL / min at 350 °C and reduce the catalyst for 4 hours); then use nitrogen as the carrier gas, add a set amount of the mixed solution of isobutyraldehyde and furfuryl alcohol, control the reaction temperature at 449 - 451 °C, the reaction pressure at 0.9 - 1.1 MPa, and react for 3.5 - 4.5 h, and collect the liquid-phase sample after the reaction.
[0013] Among them, the molar ratio of isobutyraldehyde to furfuryl alcohol is 1:1.
[0014] The advantages of the present invention are:
[0015] (1) Compared with the problems of high pollution, high corrosion, difficult separation, and difficult recovery caused by liquid base catalysts, solid base catalysts have the advantages of good stability, high catalytic activity, easy separation, and easy recovery.
[0016] (2) MgO-Al2O3 solid base catalysts exhibit excellent catalytic activity, but have poor stability due to the leaching of active phases. The Mg-Al-based solid base catalysts derived from layered double hydroxides (LDHs) have good stability and catalytic activity. At the same time, the oxides formed after the calcination of hydrotalcite have advantages such as a large specific surface area, uniform dispersion of active centers, and good thermal stability, showing good development prospects and competitive advantages.
[0017] (3) When Au particles are highly dispersed on the layered hydrotalcite support, its regular pore structure improves the surface adsorption ability of Au, and Au is easily oxidized by metal oxides, resulting in a strong interaction, making the catalyst exhibit high catalytic activity.
[0018] (4) Pd atoms exhibit high catalytic activity and selectivity under mild conditions, simplifying the esterification reaction process, improving the selectivity for the product methyl 2-furylmethyl 2-methylpropionate, and thus increasing the yield of methyl 2-furylmethyl 2-methylpropionate.
[0019] After the LDHs precursor is calcined at 300-500 °C, stable LDO is formed. LDO materials have higher catalytic activity and selectivity than LDHs materials because they contain a large number of basic sites, regular pore structures, including pore size distribution and pore volume, and a large surface area. They are important catalysts for the catalytic synthesis of organic macromolecules and play an important role in organic synthesis reactions. And due to the "memory effect" of the hydrotalcite structure, when the calcination temperature of LDHs does not exceed 500 °C, when the calcined product is placed in a specific anion solution, its LDHs layered structure can be restored. This is conducive to the recycling and reuse of LDHs materials and meets the requirements of environmental protection. Specific Embodiments
[0020] The present invention will be further described in detail below with reference to the embodiments:
[0021] Example 1
[0022] (1) Measure 6.00 mL of 2 mol / L sodium hydroxide solution and weigh 0.081 g of gold oxide hydrate (Au2O3·xH2O, Au≥82%) and dissolve them in 100 mL of deionized water. Stir evenly, add 1.00 g of sodium dodecylbenzenesulfonate (SDBS), and stir for 30 min to obtain solution A. Weigh 3.43 g of MgCl2, 2.90 g of AlCl3·6H2O, and 0.064 g of PdCl2 and dissolve them in 100 mL of deionized water, and stir evenly to obtain solution B.
[0023] (2) Under the conditions of a 60 °C water bath and strong stirring, slowly drop solution A into solution B, and continue stirring for 3 h. Let it stand and age at room temperature for 24 h, filter, wash with deionized water until the pH = 7, and vacuum dry the filter cake at 80 °C for 12 h to obtain the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst precursor, with n(Au):n(Pd) = 1:2 (molar ratio).
[0024] (3) Place the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst precursor in a muffle furnace and calcine it at 450 °C for 4 h to obtain a 4% Au-Pd / MgO-Al2O3 bimetallic solid base catalyst with a total Au-Pd metal loading.
[0025] (4) Load 0.2 g of the catalyst into a fixed-bed reactor, fill the remaining part with quartz sand, and reduce the catalyst at 350 °C and a hydrogen flow rate of 40 mL / min in the fixed-bed reactor for 4 hours. Then, use nitrogen as the carrier gas, add a mixed solution of 7.21 g of isobutyraldehyde and 9.81 g of furfuryl alcohol, control the reaction temperature at 450 °C, the reaction pressure at 1 MPa, and react for 4 h. After the reaction, collect the liquid-phase sample and analyze it by gas chromatography.
[0026] Example 2
[0027] Replace 0.064 g of PdCl2 in step (1) of Example 1 with 0.128 g of PdCl2 (n(Au):n(Pd) = 1:4, molar ratio), and the other steps are the same as in Example 1.
[0028] Example 3
[0029] Replace 0.081 g of Au2O3·xH2O in step (1) of Example 1 with 0.162 g of Au2O3·xH2O (n(Au):n(Pd) = 1:1), and the other steps are the same as in Example 1.
[0030] Example 4
[0031] Replace 0.064 g of PdCl2 in step (1) of Example 1 with 0.143 g of NiCl2·6H2O, and the other steps are the same as in Example 1.
[0032] Example 5
[0033] Replace 0.081 g of Au2O3·xH2O in step (1) of Example 1 with 0.035 g of Ag2O, and the other steps are the same as in Example 1.
[0034] Example 6
[0035] Use 6.14 g of CuCl₂·2H₂O to replace 3.43 g of MgCl₂ in step (1) of Example 1, and the other steps are the same as in Example 1.
[0036] Example 7
[0037] Use 1.95 g of FeCl₃ to replace 2.90 g of AlCl₃·6H₂O in step (1) of Example 1, and the other steps are the same as in Example 1.
[0038] Comparative Example 1
[0039] Compared with Example 1, the difference in Comparative Example 1 is that MgCl₂ is not added in step (1), and the other steps are the same as in Example 1.
[0040] Comparative Example 2
[0041] Compared with Example 1, the difference in Comparative Example 2 is that AlCl₃·6H₂O is not added in step (1), and the other steps are the same as in Example 1.
[0042] Comparative Example 3
[0043] Compared with Example 1, the difference in Comparative Example 3 is that Au₂O₃·xH₂O is not added in step (1), and the other steps are the same as in Example 1.
[0044] Comparative Example 4
[0045] Compared with Example 1, the difference in Comparative Example 4 is that PdCl₂ is not added in step (1), and the other steps are the same as in Example 1.
[0046] Analyze the data after the reaction in the examples and comparative examples, and the results are shown in Table 1:
[0047] Table 1. Comparison of isobutyraldehyde conversion rate and 2-furylmethyl 2-methylpropionate selectivity in examples and comparative examples
[0048]
[0049] The bimetallic solid base catalyst of the present invention has a significant effect on the esterification reaction of isobutyraldehyde and furfuryl alcohol to prepare methyl 2-furyl-2-methylpropionate. The MgO-Al2O3 solid base catalyst exhibits excellent catalytic activity, and the doping of Au and Pd elements further improves the catalytic activity and selectivity of the MgO-Al2O3 solid base catalyst. When Au particles are highly dispersed on the layered hydrotalcite support, its regular pore structure improves the surface adsorption capacity of Au, and Au is easily oxidized by metal oxides, thereby generating a strong interaction, making the catalyst exhibit high catalytic activity. At the same time, Pd atoms exhibit high catalytic activity and selectivity under mild conditions, simplifying the esterification reaction process and improving the conversion rate of raw materials and the selectivity of products. The preparation method of the solid base catalyst of the present invention is simple, the catalyst cost is low and the stability is high, which can effectively solve the problems brought by the liquid base catalysis process, such as equipment corrosion, environmental pollution, difficult separation of catalyst and product, and poor recycling performance, and has great market competition advantages.
[0050] The described embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Without departing from the essence of the present invention, any obvious improvements, substitutions or variations that those skilled in the art can make all belong to the protection scope of the present invention.
Claims
1. A method for preparing methyl 2-furyl-2-methylpropionate by the esterification reaction of isobutyraldehyde and furfuryl alcohol, characterized in that: It includes the following steps: loading the catalyst into a fixed-bed reactor, filling the remaining part with quartz sand, fully reducing it with hydrogen, then using nitrogen as the carrier gas, adding a mixed solution of a set amount of isobutyraldehyde and furfuryl alcohol, controlling the reaction temperature at 449 - 451 °C, the reaction pressure at 0.9 - 1.1 MPa, and reacting for 3.5 - 4.5 h; The catalyst is a bimetallic solid base catalyst, and the preparation method includes the following steps: (1) Dissolving gold hydrate oxide and / or gold oxide and / or silver oxide in sodium hydroxide solution, dispersing evenly, adding sodium dodecylbenzenesulfonate, and obtaining solution A after uniform dispersion; dissolving magnesium chloride, aluminum chloride, and palladium chloride in deionized water, and stirring evenly to obtain solution B; the molar ratios are: n(Mg):n(Al) = 3:1, n(NaOH):n(Al) = 1:1, n(Au):n(Pd) = 1:2; (2) Under a water bath at 59 - 61 °C with strong stirring, slowly dripping solution A into solution B, continuing to stir for 2.5 - 3.5 h, standing and aging at room temperature for 23.5 - 24.5 h, filtering, washing with deionized water until neutral, and drying the filter cake under vacuum to obtain the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst precursor; (3) Calcining the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst precursor at 300 - 500 °C for 3 - 10 h to obtain the Au-Pd / MgO-Al2O3 bimetallic solid base catalyst.
2. The method for preparing methyl 2-furyl propionate by the esterification reaction of isobutyraldehyde and furfuryl alcohol according to claim 1, characterized in that: In step (3), the calcination temperature is 450 - 500 °C.
3. The method for preparing methyl 2-furyl propionate by the esterification reaction of isobutyraldehyde and furfuryl alcohol according to claim 1, characterized in that: In step (2), the temperature of the water bath is 60 °C, the vacuum drying temperature is 30 - 120 °C, and the drying time is 12 - 24 h.
4. The method for preparing methyl 2-furylpropionate by the esterification reaction of isobutyraldehyde and furfuryl alcohol according to claim 1, wherein: The molar ratio of isobutyraldehyde to furfuryl alcohol is 1:
1.
5. The method for preparing methyl 2-furyl-2-methylpropionate by the esterification reaction of isobutyraldehyde and furfuryl alcohol according to claim 1, characterized in that: The reduction temperature is 350 °C, the hydrogen flow rate is 40 mL / min, and the reduction time is 4 hours.