Synthetic glycerol carbonate copper-palladium alloy catalyst and preparation method and application thereof
By preparing a Pd-Cu-NC catalyst, the problems of low yield and low conversion rate of glycerol to glycerol carbonate were solved, and efficient and stable synthesis of glycerol carbonate was achieved, which meets the requirements of green chemistry.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGNAN UNIV
- Filing Date
- 2023-12-19
- Publication Date
- 2026-06-19
AI Technical Summary
Existing technologies for converting glycerol to glycerol carbonate have low yields, low conversion rates, and poor catalyst stability. In particular, the transesterification and urea alcoholysis methods suffer from environmental pollution and high costs.
A Cu-ZIF-8 support was generated by reacting Zn(NO3)2·6H2O and Cu(NO3)2·3H2O with 2-methylimidazole in an alcohol solution. This support was then combined with a palladium methanol solution to form Pd/Cu-ZIF-8. The Pd-Cu-NC catalyst was prepared by high-temperature calcination and then reacted with glycerol and potassium iodide in the presence of oxygen and carbon monoxide to generate glycerol carbonate.
The synthesis of glycerol carbonates was achieved with high efficiency and low cost. The catalyst has high stability, which is in line with the sustainable development concept of green chemistry, and the yield and selectivity are significantly improved.
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Figure CN117861703B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of oleochemical technology, and in particular to a synthetic carbonate catalyst, its preparation method, and its application. Background Technology
[0002] Glycerol, as the primary waste product of the biodiesel industry, has long been a hot topic for researchers in its recycling. Glyceryl carbonate, a green chemical intermediate with a cyclic structure containing both hydroxyl and carbonyl groups, can be used as a surfactant, electrolyte, synthetic intermediate, in the synthesis of polyurethane compounds, and in coatings, finding wide applications in organic synthesis, oleochemicals, pharmaceuticals, plastics, and cosmetics production.
[0003] Processes for synthesizing glycerol carbonate from glycerol include the phosgene method, transesterification, and enzymatic hydrolysis. The phosgene used in the phosgene method is not only highly corrosive but also extremely toxic; the transesterification method, due to its high production cost and difficulty in product separation, is still not suitable for large-scale use. The urea alcoholysis method produces ammonia during the reaction and places stringent requirements on the process equipment. In contrast, the carbonylation method is not only environmentally friendly and in line with sustainable development principles, but also produces only water as a final byproduct, making it a promising research hotspot. Summary of the Invention
[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problems of low yield, low conversion rate and poor catalyst stability in the prior art.
[0005] To address the aforementioned technical problems, this invention provides a catalyst for the synthesis of glycerol carbonate, its preparation method, and its applications. This catalyst is characterized by its simple preparation, low cost, high catalytic efficiency, and good stability.
[0006] The first objective of this invention is to provide a method for preparing a catalyst for the synthesis of glycerol carbonate, comprising the following steps:
[0007] (1) Zn(NO3)2·6H2O, Cu(NO3)2·3H2O, and 2-methylimidazole were dissolved in alcohol solutions to obtain metal solutions and ligand solutions, respectively. Then, the metal solutions and ligand solutions were mixed and reacted at 100-200℃ for 10-30h. After cooling and standing for 3-6h, the support Cu-ZIF-8 was obtained.
[0008] (2) Dissolve Cu-ZIF-8 obtained in step (1) in an alcohol solution, then mix and stir it with a methanol solution of palladium, then filter and dry to obtain Pd / Cu-ZIF-8.
[0009] (3) The Pd / Cu-ZIF-8 obtained in step (2) is calcined at 800-950℃ for 2-6 hours under nitrogen to obtain the catalyst Pd-Cu-NC for the synthesis of glycerol carbonate.
[0010] In one embodiment of the present invention, in step (1), the mass ratio of Zn(NO3)2·6H2O and Cu(NO3)2·3H2O is 3 to 5:1.
[0011] In one embodiment of the present invention, in step (1), the ratio of the total mass of Zn(NO3)2·6H2O and Cu(NO3)2·3H2O to the volume of the alcohol solution is 5g:40-50mL.
[0012] In one embodiment of the present invention, in step (1), the alcohol solution is methanol.
[0013] In one embodiment of the present invention, in step (1), the mass-to-volume ratio of 2-methylimidazole to the alcohol solution is 9.72 g: 40-50 mL.
[0014] In one embodiment of the present invention, in step (1), the mixing volume of the metal solution and the ligand solution is 1:0.5 to 1.5.
[0015] In one embodiment of the present invention, in step (2), the mass-to-volume ratio of Cu-ZIF-8 to alcohol solution is 0.9 g: 40-50 mL.
[0016] In one embodiment of the present invention, in step (2), palladium is palladium acetate.
[0017] In one embodiment of the present invention, in step (2), the concentration of the palladium methanol solution is 0.5-1.5 g / L.
[0018] In one embodiment of the present invention, in step (2), the mass-to-volume ratio of Cu-ZIF-8 and palladium methanol solution is 0.9 g: 15-25 mL.
[0019] In one embodiment of the present invention, in step (2), the stirring time is 20 to 24 hours.
[0020] A second objective of this invention is to provide a method for preparing a catalyst for the synthesis of glycerol carbonate.
[0021] A third objective of this invention is to provide an application of the aforementioned synthetic glycerol carbonate catalyst in the fields of oleochemicals, plastics, or cosmetics production.
[0022] The present invention also provides a method for synthesizing glycerol carbonate, comprising the following steps:
[0023] Glycerol, a catalyst for synthesizing glycerol carbonate, and potassium iodide are mixed evenly and reacted in the presence of oxygen and carbon monoxide to obtain glycerol carbonate.
[0024] Furthermore, the mass ratio of glycerol, the catalyst for synthesizing glycerol carbonate, and potassium iodide is 1-2:0.001-0.05:0.01-0.03.
[0025] Preferably, the mass ratio of glycerol, the catalyst for synthesizing glycerol carbonate, and potassium iodide is 1-2:0.0015:0.01-0.03.
[0026] Furthermore, the pressure ratio of oxygen to carbon monoxide is 1:2-3.
[0027] Furthermore, the reaction is carried out at 135-145°C for 1-5 hours.
[0028] The technical solution of the present invention has the following advantages over the prior art:
[0029] (1) The catalyst for synthesizing glycerol carbonate described in this invention is supported by a metal-organic framework material and then calcined at high temperature to form a nitrogen-carbon material. The nitrogen species on the surface of the NC material can regulate the chemical state and dispersion of Pd, so that palladium and copper form a copper-palladium alloy, and can also promote the adsorption and activation of glycerol molecules.
[0030] (2) The catalyst for synthesizing glycerol carbonate described in this invention is an alloy catalyst. During the calcination process, the copper atoms that form the framework and the divalent palladium form a copper-palladium alloy, which is encapsulated in the framework, and finally a catalyst with extremely high stability is obtained.
[0031] (3) The catalyst described in this invention is prepared under normal pressure and is simple to operate. Its precursor is Cu-ZIF-8 material. Therefore, Pd-Cu-NC inherits the high specific surface area and uniform porous structure of Cu-ZIF-8. Under this condition, the only byproduct of the reaction is water, which is in line with the concept of green chemistry and sustainable development. Attached Figure Description
[0032] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:
[0033] Figure 1 The Fourier transform infrared spectra are for Examples 1, 2, 4, and 5.
[0034] Figure 2 The image shows the XRD patterns of the alloy catalyst and support, as well as the Pd-Cu-MOF catalyst, in Example 1. Detailed Implementation
[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.
[0036] Example 1
[0037] A method for preparing a catalyst for the synthesis of glycerol carbonate specifically includes the following steps:
[0038] (1) 3.972 g Zn(NO3)2·6H2O and 1.08 g Cu(NO3)2·3H2O were added to a 100 mL hydrothermal reactor with a polytetrafluoroethylene liner and dissolved in 45 mL methanol to obtain a metal solution. Then, 9.72 g 2-methylimidazole was weighed into a 50 mL beaker and dissolved in 45 mL methanol to obtain a ligand solution. The ligand solution was quickly poured into the metal solution, and the temperature was increased to 140 °C in the hydrothermal reactor at a rate of 5 °C / min. The reaction was carried out at this temperature for 24 h, and then cooled to room temperature at a rate of 2 °C / min. After the reaction was completed, the mixture was filtered, and the remaining solid was washed three times with methanol and then dried at 80 °C for 24 h to obtain copper-doped ZIF-8 (Cu-ZIF-8).
[0039] (2) Take 0.9g of the Cu-ZIF-8 obtained above and put it into a 250mL beaker. Disperse it with 45mL of methanol, then pour in 21mL of palladium acetate methanol solution (1g / L), stir for 24h, filter, and dry at 80℃ for 24h to obtain Pd / Cu-ZIF-8.
[0040] (3) The Pd / Cu-ZIF-8 obtained above was placed in a tube furnace and calcined at 950°C for 4 hours under nitrogen conditions to obtain the final catalyst Pd-Cu-NC.
[0041] Figure 1 The Fourier transform infrared spectra of Examples 1, 2, 4, and 5 show that both the alloy catalyst and other comparable metal-organic framework catalysts perfectly inherit the basic functional groups that a metal-organic framework should have.
[0042] Figure 2The XRD patterns of the alloy catalyst and support of Example 1, as well as the catalyst Pd-Cu-MOF, are shown. The XRD patterns of the prepared Pd-Cu-NC and Cu-NC show a broad peak at 24.3°. These peaks correspond to the (002) crystal plane of carbon. Peaks appearing at 25.12, 42.96, 49.98, and 62.12° correspond to the (101), (117), (200), and (2010) crystal planes of face-centered cubic Cu-Pd, respectively (PDF#65-9675). In addition, (111) and (200) crystal planes corresponding to copper-zinc alloys were found at 43.70 and 50.79° (PDF#65–6567).
[0043] Example 2
[0044] A catalyst for synthesizing glycerol carbonate and its preparation method thereof, specifically including the following steps:
[0045] Basically the same as in Example 1, except that Zn(NO3)2·6H2O in step (1) is removed, and the solvent is changed from methanol to ammonia (mass fraction of 10%). The support finally obtained in step (1) is Cu-MOF. Then, the remaining steps of Example 1 are followed to obtain the catalyst Pd-Cu-MOF.
[0046] Example 3
[0047] A catalyst for synthesizing glycerol carbonate and its preparation method thereof, specifically including the following steps:
[0048] Basically the same as in Example 1, except that Zn(NO3)2·6H2O and Cu(NO3)2·3H2O in step (1) are removed, and the carrier finally obtained in step (1) is ZIF-8. Then, the remaining steps of Example 1 are followed to obtain Pd-NC.
[0049] Example 4
[0050] A catalyst for synthesizing glycerol carbonate and its preparation method thereof, specifically including the following steps:
[0051] Basically the same as in Example 1, except that step (3) is omitted to obtain Pd / Cu-ZIF-8.
[0052] Example 5
[0053] A catalyst for synthesizing glycerol carbonate and its preparation method thereof, specifically including the following steps:
[0054] Basically the same as in Example 1, except that the order of steps (2) and (3) is reversed, and sodium borohydride, a reducing agent, is added in the third step, and palladium source is changed to palladium chloride, to obtain Pd. NPS / Cu-NC, the specific operation is as follows:
[0055] (2) Cu-ZIF-8 was placed in a tube furnace and heated to 950°C at 5°C / min for 4 hours under nitrogen protection to obtain copper-doped nitrogen-carbon material (Cu-NC);
[0056] (3) 0.9 g of copper-doped nitrogen-carbon material (Cu-NC) was added to 90 mL of methanol, followed by 1 g / L of palladium dichloride ammonia solution (10% ammonia solution; a total of 27 mL of palladium dichloride ammonia solution), stirred for 2 h, and then sodium borohydride solution (0.9 g / L, a total of 18 mL) was added dropwise. The reaction was continued at room temperature and 500 rpm for 24 h, filtered, and dried at 80 °C for 24 h to obtain palladium-supported Cu-ZIF catalyst (Pd / Cu-NC).
[0057] Example 6
[0058] The catalyst from Example 1 was used. 1.446 g of glycerol was added to a 50 mL polytetrafluoroethylene liner. Reactions with 0.001 g, 0.0015 g, 0.002 g, 0.0025 g, and 0.003 g of catalyst and 0.018 g of KI were then stirred until homogeneous. The mixture was purged three times with O2, followed by the introduction of oxygen and carbon monoxide (O2:CO = 1.3:2.7, pressure ratio), and the reaction was carried out at 140 °C for two hours. The results showed that the yield increased with increasing catalyst dosage; at 0.015 g, a higher yield could be obtained with less catalyst.
[0059] Table 1
[0060]
[0061] Example 7
[0062] The catalyst from Example 1 was used. 1.446 g of glycerol, 0.015 g of catalyst (Pd-Cu-NC), and 0.018 g of KI were added to a 50 mL polytetrafluoroethylene liner and stirred until homogeneous. The mixture was purged three times with O2, followed by the introduction of oxygen and carbon monoxide (O2:CO = 1.3:2.7). The reaction was carried out at 140 °C for two hours. This experiment was repeated three times, and the average value was taken. The results showed that the catalyst activity could achieve a yield of 95.32% and a selectivity of 99.06%.
[0063] Table 2
[0064]
[0065] Example 8
[0066] Four catalysts obtained in Examples 1, 2, 3, and 4 were tested for activity. 1.446 g of glycerol, 0.015 g of catalyst, and 0.018 g of KI were added to 50 mL of polytetrafluoroethylene liner and stirred until homogeneous. The mixture was purged three times with O2, followed by the introduction of oxygen and carbon monoxide (O2:CO = 1.3:2.7, pressure ratio). The reaction was carried out at 140°C for two hours. The results showed that Pd-Cu-NC exhibited better catalytic activity. This indicates that the presence of copper promotes the palladium metal catalytic reaction. Furthermore, by altering the microenvironment of the copper support during calcination—for example, the biggest difference between Cu-ZIF-8 and Cu-MOF is that zinc volatilizes during calcination of Cu-ZIF-8—more vacancies are generated when copper and palladium form an alloy, resulting in a better catalytic effect.
[0067] Table 3
[0068]
[0069] Example 9
[0070] The catalysts obtained in Examples 1 and 5 were subjected to stability tests in a 50 mL high-pressure reactor. 1.446 g of glycerol, 0.02 g of catalyst, and 0.018 g of KI were added to a 50 mL polytetrafluoroethylene liner and stirred until homogeneous. The mixture was purged three times with O2, followed by the introduction of oxygen and carbon monoxide (O2:CO = 1.3:2.7, pressure ratio). The reaction was carried out at 140 °C for two hours. After the reaction, the mixture was centrifuged, and the reaction solution was separated from the catalyst. This process was then repeated five times with the same amount of reactants. The results showed that the alloy Pd-Cu-NC catalyst exhibited higher stability than the traditional palladium nanoparticle catalysis, with almost no decrease in yield after five catalytic cycles.
[0071] Table 4
[0072]
[0073]
[0074] Table 5
[0075]
[0076] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A method of synthesizing glycerol carbonate, characterized by, Includes the following steps: Glycerol, a catalyst for synthesizing glycerol carbonate, and potassium iodide are mixed evenly and reacted in the presence of oxygen and carbon monoxide to obtain glycerol carbonate. The mass ratio of glycerol, the catalyst for synthesizing glycerol carbonate, and potassium iodide is 1-2 : 0.001-0.05 : 0.01-0.
03. The preparation method of the catalyst for synthesizing glycerol carbonate includes the following steps: (1) Zn(NO3)2·6H2O, Cu(NO3)2·3H2O, and 2-methylimidazole were dissolved in alcohol solutions to obtain metal solutions and ligand solutions, respectively. Then the metal solutions and ligand solutions were mixed and reacted at 100-200 °C for 10-30 h. After cooling and standing for 3-6 h, the support Cu-ZIF-8 was obtained. (2) Dissolve Cu-ZIF-8 obtained in step (1) in an alcohol solution, then mix and stir with a methanol solution of palladium, then filter and dry to obtain Pd / Cu-ZIF-8; (3) The Pd / Cu-ZIF-8 obtained in step (2) is calcined at 800-950 °C for 2-6 h under nitrogen to obtain the catalyst Pd-Cu-NC for the synthesis of glycerol carbonate.
2. The method of claim 1, wherein, In step (1), the mass ratio of Zn(NO3)2·6H2O and Cu(NO3)2·3H2O is 3~5:1; the ratio of the total mass of Zn(NO3)2·6H2O and Cu(NO3)2·3H2O to the volume of the alcohol solution is 5g:40~50mL.
3. The method of claim 1, wherein, In step (1), the mass-to-volume ratio of 2-methylimidazole to the alcohol solution is 9.72 g : 40~50 mL.
4. The method of claim 1, wherein, In step (1), the volume ratio of the metal solution to the ligand solution is 1:0.5~1.
5.
5. The method of claim 1, wherein, In step (2), the mass-volume ratio of Cu-ZIF-8 to alcohol solution is 0.9 g : 40~50 mL.
6. The method of claim 1, wherein, In step (2), palladium is palladium acetate; the concentration of the palladium methanol solution is 0.5-1.5 g / L; the mass-volume ratio of Cu-ZIF-8 and palladium methanol solution is 0.9 g : 15~25 mL.
7. The method of claim 1, wherein, The pressure ratio of oxygen to carbon monoxide is 1:2-3; the reaction is carried out at 135-145℃ for 1-5 hours.