A method for the photocatalytic conversion of glycerol to prepare acetol and syngas
By using metal-doped cadmium sulfide catalyst for photocatalytic dehydration under visible light, the problem of poor product stability and many side reactions when glycerol is converted to acetone alcohol in the prior art is solved, and acetone alcohol and synthesis gas preparation under high selectivity and mild conditions is achieved.
Patent Information
- Application Number
- CN202310542317.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-15
- Publication Date
- 2025-07-01
- Estimated Expiration
- 2043-05-15
AI Technical Summary
The prior art uses acidic or alkaline oxides as catalysts at high temperatures, resulting in poor product stability, many side reactions and low selectivity when glycerol is converted to acetone alcohol.
Glycerol is used as raw material, under visible light conditions, and inert gas protection is used, and photocatalytic dehydration is performed by metal-doped cadmium sulfide catalyst at room temperature to obtain the liquid phase product acetone alcohol and the gas phase product synthesis gas.
Acetone alcohol and synthesis gas are prepared with high selectivity under mild conditions, avoiding the generation of carbon accumulation and side reactions, the catalytic system is simple, efficient, and the catalyst can be recycled.
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Abstract
Description
Technical Field
[0001] The present invention relates to a method for the photocatalytic conversion of glycerol to prepare acetol and syngas (H2 + CO). Background Art
[0002] Acetol is an important chemical, which can be used to produce pharmaceuticals, spices, dyes, and can also be used as an organic synthesis intermediate, a solvent for nitrocellulose, a peptide synthesis protecting agent, etc. The traditional method for synthesizing acetol uses glycerol as a substrate and obtains it in the gas phase at a high temperature of 200 - 400 °C with an acidic or basic oxide as a catalyst.
[0003] Chang once reported that 5% Na / CeO2 basic metal oxide prepared by co - precipitation method and calcination method was used as a catalyst for the gas - phase reaction of glycerol in a continuous fixed - bed, and glycerol was converted into acetol at 350 °C, and the conversion rate of glycerol reached 20%. Batiot - Dupeyrat et al. used basic catalysts lanthanum oxide and perovskite LaNiO3 to convert pure glycerol in the gas phase at 400 - 500 °C, and found that the highest selectivity for acetol was 26.5%, but glycerol polymerized to form heavy products in the liquid phase. The thermal catalytic process usually has disadvantages such as poor product stability, many side reactions, and low selectivity. The present invention uses photocatalytic glycerol to obtain acetol and syngas, which can be converted at a suitable temperature, avoiding problems such as carbon deposition, many side reactions, and low selectivity.
[0004] The present invention uses glycerol as a raw material. Under the condition of visible - light illumination and in an inert - gas protection, liquid - phase product acetol can be obtained at room temperature, accompanied by the gas - phase product syngas. The selectivity of acetol is high, the experimental conditions are mild, and it has good application prospects. Summary of the Invention
[0005] The present invention aims to solve the technical problems existing in the prior art and provides a method for the photocatalytic conversion of glycerol to prepare acetol and syngas (H2 + CO).
[0006] The technical solution of the present invention is as follows:
[0007] A method for the photocatalytic conversion of glycerol to prepare acetol and syngas is as follows: In the method, glycerol is used as a substrate. Under the condition of visible - light illumination and in an inert - gas atmosphere, under the action of a catalyst, glycerol undergoes photocatalytic dehydration to obtain a liquid - phase product acetol and a gas - phase product syngas (H2 + CO).
[0008] Further, the mass ratio of the catalyst dosage to the mass of glycerol is 20 - 50 wt%, preferably 50 wt%.
[0009] Further, the catalyst is metal-doped cadmium sulfide. More specifically, the doped metal is one of Fe, Co, Cu, Pt, and Mn. Preferably, the catalyst is manganese-doped cadmium sulfide Mn / CdS.
[0010] Further, the mass content of the doped metal as the metal active component in the catalyst is 1-10 wt%, preferably 3 wt%.
[0011] Further, the inert gas is a gas without oxygen and hydrogen, such as nitrogen, argon, etc.
[0012] Further, the reaction temperature is 15-60 °C, and the reaction time is 6-48 h.
[0013] Further, glycerol needs to be dissolved in a solvent before the reaction. The solvent is an acetonitrile and water mixed solvent. The volume of acetonitrile accounts for 0-95% of the total solvent, preferably 95%. Further, the wavelength of the visible light illumination is 300-500 nm.
[0014] The present invention has the following characteristics: The present invention provides a new process for the dehydration of glycerol to acetol. Under visible light excitation, the substrate molecules themselves do not absorb light, and a photocatalyst is required. The present invention discovers that Mn / CdS can achieve the dehydration of one molecule of glycerol under visible light to produce the liquid-phase product acetol. The method of the present invention has mild conditions, high product selectivity, and good application prospects. The catalytic system of the present invention is simple, efficient, with few by-products, less catalyst consumption, and the catalyst can be recycled. Detailed implementation mode
[0015] The present invention will be described below through specific examples, but the implementation of the present invention is not limited to these examples:
[0016] Examples 1-5: Add 10 mg of glycerol, 5 mg of Mn / CdS, and 1 mL of different ratios of acetonitrile and water mixed solvent to a photoreaction tube with a magnetic stirrer. Pass argon to displace air and seal the reaction tube. Select an LED light with a wavelength of 455 nm and a light intensity of 18 w, and react at 30 °C for 24 h. After the reaction, add the internal standard helium gas, and the syngas of the gas-phase product is analyzed by the internal standard method in a gas chromatograph, and the liquid-phase product acetol is analyzed by the external standard method in a liquid chromatograph. The results are shown in Table 1.
[0017] Table 1 Influence of solvent ratio on the conversion of glycerol to acetol and syngas
[0018]
[0019] Analyzing the results in Table 1, it can be seen that when the volume ratio of acetonitrile to water is 9.5:0.5, the formation rate of acetol is the fastest.
[0020] Examples 6 - 10: Add 10 mg of glycerol, 5 mg of different metal - doped CdS catalysts, and 1 mL of a mixed solvent of acetonitrile and water with a volume ratio of 9.5:0.5 into a photoreaction tube with a magnetic stir bar. Purge the air with argon and seal the reaction tube. Select an LED light with a wavelength of 455 nm and a light intensity of 18 w, and react at 30 °C for 24 h. Qualitatively and quantitatively analyze the gas and liquid in the reaction tube using gas chromatography and liquid chromatography. The results are shown in Table 2.
[0021] Table 2 Influence of different metal - doped CdS catalysts on the conversion of glycerol to acetol and syngas
[0022]
[0023]
[0024] Analysis of the results in Table 2 shows that different metal - doped cadmium sulfides can catalyze the conversion of glycerol to acetol and syngas. When manganese - doped cadmium sulfide is used as the catalyst, the formation rate of acetol is the fastest.
[0025] Examples 11 - 15: Add 10 mg of glycerol, 5 mg of Mn - doped CdS with different mass contents, and 1 mL of a mixed solvent of acetonitrile and water with a volume ratio of 9.5:0.5 into a photoreaction tube with a magnetic stir bar. Purge the air with argon and seal the reaction tube. Select an LED light with a wavelength of 455 nm and a light intensity of 18 w, and react at 30 °C for 24 h. Qualitatively and quantitatively analyze the gas and liquid in the reaction tube using gas chromatography and liquid chromatography. The results are shown in Table 3.
[0026] Table 3 Influence of the doping amount of Mn on the conversion of glycerol to acetol and syngas
[0027]
[0028] Analysis of the results in Table 3 shows that Mn - doped cadmium sulfides with different contents can catalyze the conversion of glycerol to acetol and syngas. When the doping amount of Mn is 3 wt%, the formation rate of acetol is the fastest.
Claims
1. A method for the photocatalytic conversion of glycerol to prepare acetol and syngas, characterized in that, Specifically as follows: The described method uses glycerol as a substrate. Under visible light illumination conditions and in an inert gas atmosphere, glycerol undergoes photocatalytic dehydration under the action of a catalyst to obtain a liquid-phase product of acetol and a gas-phase product of syngas. The catalyst is cadmium sulfide doped with metal. The wavelength of the visible light illumination is 300 - 500 nm. Before the reaction, glycerol needs to be dissolved in a solvent, and the solvent is a mixed solvent of acetonitrile and water. Among them, the volume of acetonitrile accounts for 0 - 95% of the total solvent. The doped metal is one of Fe, Co, Cu, Pt, and Mn.
2. The method for preparing acetol and syngas by photocatalytic conversion of glycerol according to claim 1, wherein, The mass ratio of the catalyst dosage to the mass of glycerol is 20 - 50 wt%.
3. A method for preparing acetol and syngas by photocatalytic conversion of glycerol according to claim 1 or 2, characterized in that, The mass content of the doped metal as the metal active component in the catalyst is 1 - 10 wt%.
4. A method for preparing acetol and syngas by photocatalytic conversion of glycerol according to claim 1, characterized in that, The inert gas is a gas without oxygen and hydrogen.
5. A method for preparing acetol and syngas by photocatalytic conversion of glycerol according to claim 1, characterized in that, The reaction temperature is 15 - 60 °C, and the reaction time is 6 - 48 h.
6. A method for preparing acetol and syngas by photocatalytic conversion of glycerol according to claim 3, characterized in that, The mass content of the doped metal as the metal active component in the catalyst is 3 wt%.
Citation Information
Patent Citations
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