A method for producing carbon monoxide and ethylene glycol by photolysis of dihydroxyacetone
By ultraviolet photolysis of dihydroxyacetone at room temperature and normal pressure, the problem of high temperature and high pressure in traditional methods is solved, and rapid and efficient green production is achieved, with high purity and high yield.
Patent Information
- Application Number
- CN202310873583.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-17
- Publication Date
- 2025-07-11
- Estimated Expiration
- 2043-07-17
AI Technical Summary
In the prior art, the production methods of carbon monoxide and glycol require high temperature and high pressure, resulting in energy crises and environmental problems, and the production rate and purity of the traditional methods are low, limiting their industrial applications.
Ultraviolet photolysis dihydroxyacetone is directly converted into carbon monoxide and ethylene glycol under normal pressure at room temperature and normal pressure, and the appropriate ultraviolet wavelength, solvent and atmosphere conditions are selected to achieve photolysis reaction.
It realizes the rapid production of high-purity carbon monoxide and high-yield glycol at room temperature and normal pressure, with a fast reaction rate, no catalyst required, and has green and environmentally friendly characteristics.
Smart Images
Figure CN117164430B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of the preparation of carbon monoxide and ethylene glycol, and particularly relates to a method for producing carbon monoxide and ethylene glycol by photolyzing dihydroxyacetone. Background Art
[0002] Carbon monoxide is a bulk chemical raw material in the petrochemical and coal chemical industries and can be used to synthesize bulk chemicals such as formic acid, aldehydes and alcohols, olefins, and aromatics. Currently, the production of carbon monoxide generally adopts traditional industrial methods such as steam reforming, partial oxidation, and gasification of non-renewable fossil fuel-based natural gas, petroleum, and coal. These methods require harsh conditions of high temperature or high pressure and bring about energy crises and environmental problems. Mild reduction methods (such as photoreduction and electroreduction) can achieve the catalytic reduction of carbon dioxide to carbon monoxide, but the low production rate or purity of carbon monoxide greatly limits their industrial scale-up.
[0003] Ethylene glycol is also an important chemical and is often used as a monomer of polyester fiber, antifreeze, coolant, and energy carrier, etc. Currently, the industrial production methods of ethylene glycol mainly include the ethylene method and the oxalate method. The ethylene method first oxidizes ethylene produced from fossil fuels to ethylene oxide and then obtains ethylene glycol through a hydration reaction. The oxalate method is a method of first catalytically synthesizing oxalic acid diester from coal-derived carbon monoxide and then hydrogenating and reducing oxalic acid diester to prepare ethylene glycol. The preparation methods of ethylene glycol still face harsh conditions of high temperature / high pressure and bring about energy crises and environmental problems. It is urgent to explore new process methods for the rapid continuous flow production of carbon monoxide and ethylene glycol at room temperature and atmospheric pressure. Summary of the Invention
[0004] The present invention provides a method for directly and rapidly photodissociating renewable biomass dihydroxyacetone into carbon monoxide and ethylene glycol at room temperature and atmospheric pressure. This method has the advantages of room temperature and atmospheric pressure, low equipment requirements, simple operation, environmental friendliness, and no need for a catalyst.
[0005] The technical solution of the present invention is as follows:
[0006] A method for producing carbon monoxide and ethylene glycol by photolyzing dihydroxyacetone uses ultraviolet light as a light source to convert dihydroxyacetone into carbon monoxide and ethylene glycol.
[0007] Furthermore, the photolysis activity of dihydroxyacetone is related to the selection of the ultraviolet light wavelength. The closer the ultraviolet light wavelength is to the ultraviolet-visible absorption peak value of dihydroxyacetone, the more likely it is to have the maximum photolysis reaction rate. The light absorption wavelength of the carbonyl group in the dihydroxyacetone molecule is between 230 nm and 320 nm, and the absorption peak is approximately at 273 nm. Therefore, the wavelength of the used ultraviolet light source is 200 nm - 340 nm. The preferred wavelength of the ultraviolet light source is 250 nm - 310 nm.
[0008] Further, dihydroxyacetone needs to be dissolved in a solvent for conversion.
[0009] Further, dihydroxyacetone is generally a dimer solid of aldol condensation, and mainly exists in the form of monomeric dihydroxyacetone in the dihydroxyacetone solution. The dihydroxyacetone solution can uniformly absorb the irradiated ultraviolet light, which is beneficial to its photodissociation reaction. The solvent can also affect the peak position of the absorption peak of the carbonyl group in dihydroxyacetone. The solvent used for photolyzing dihydroxyacetone is one or more of water, methanol, ethanol, and acetonitrile, and the preferred solvent is water or a mixture of acetonitrile and water.
[0010] Further, the molar concentration of dihydroxyacetone in the solvent is less than 2.5 M. The preferred molar concentration is less than 1.0 M.
[0011] Further, the photolysis activity of dihydroxyacetone is weakly related to the ambient atmosphere. The atmosphere used for photolyzing dihydroxyacetone is vacuum or one or more of argon, nitrogen, oxygen, air, carbon dioxide, and hydrogen. Among them, oxygen or air has a weak effect on the yields of carbon monoxide and ethylene glycol produced by the photolysis of dihydroxyacetone.
[0012] The carbonyl group of the dihydroxyacetone molecule absorbs a certain amount of ultraviolet light, and the dihydroxyacetone molecule is activated to the excited state (n→π*). The energy of the ultraviolet light is equivalent to and of the same order of magnitude as the energy of the carbon-carbon covalent bond in the dihydroxyacetone molecule. The carbon-carbon bond of the dihydroxyacetone molecule undergoes a radical process of cleavage to release carbon monoxide, and the hydroxymethyl radical further couples to obtain ethylene glycol.
[0013] Advantages of the present invention: The method of the present invention has the characteristics of fast reaction rate, no need for a catalyst, and room temperature and atmospheric pressure conditions. Among them, the carbon monoxide yield > 95%, the carbon monoxide purity > 99.9%, and the ethylene glycol yield > 80%. Description of the Drawings
[0014] Figure 1 Online mass spectrometry diagram of gaseous carbon monoxide in Example 3.
[0015] Figure 2 Mass spectrometry diagram of liquid-phase ethylene glycol in Example 3, A gas chromatography-mass spectrometry diagram of the liquid-phase product, B mass spectrometry corresponding to the main peak of ethylene glycol.
[0016] Figure 3 Optical photograph of the flow reaction device in Example 21, A diagram of the flow reaction device, B spiral quartz reaction tube surrounding the ultraviolet lamp. Detailed Embodiments
[0017] The present invention will be described below through specific examples, but the implementation of the present invention is not limited to these examples. The reaction conditions and the corresponding photolysis reaction results are shown in Table 1.
[0018] Examples 1 - 6 (Light source wavelength): Take 1 mL of 0.1 mol / L dihydroxyacetone aqueous solution in a quartz tube, seal it with a padded lid, and replace the atmosphere in the tube with argon. Under stirring, irradiate it with 16W LED ultraviolet light of different wavelengths for 1 h. After the photolysis reaction, the gaseous product carbon monoxide is quantitatively and qualitatively analyzed using a gas chromatograph and an on-line mass spectrometer, and the liquid-phase dihydroxyacetone substrate and ethylene glycol product are quantitatively and qualitatively analyzed using a high-performance liquid chromatograph and a gas chromatography-mass spectrometry instrument. The on-line mass spectrum determines that the gas product during the photolysis process is carbon monoxide ( Figure 1 ), and the gas chromatography-mass spectrum determines that the liquid-phase product during the photolysis process is ethylene glycol ( Figure 2 ). In the range of light source wavelengths from 200 nm to 320 nm, the photolysis conversion rate of dihydroxyacetone is high, and the yields of carbon monoxide and ethylene glycol are high (Examples 1 - 5). Among them, the ultraviolet light with a main peak wavelength of 275 nm (in the range of 250 nm - 310 nm) has the best photolysis reaction result: the conversion rate of dihydroxyacetone is 100%, the yield of carbon monoxide is 98%, the purity of carbon monoxide > 99.9%, and the yield of ethylene glycol is 80% (Example 4).
[0019] Examples 7 - 11 (Solvent): Except for the different solvents, other conditions are the same as in Example 4. The solvent has an important influence on the photolysis reaction, affecting the photolysis activity of dihydroxyacetone and the selectivity of the reaction. Dihydroxyacetone dissolved in a solvent is more conducive to the photolysis reaction than in powder form, and the dihydroxyacetone aqueous solution has the best photolysis activity.
[0020] Examples 12 - 13 (Atmosphere): Except for the different atmospheres, other conditions are the same as in Example 4. The ambient atmosphere has a relatively small influence on the photolysis reaction effect of dihydroxyacetone. The yield of ethylene glycol after the photolysis of dihydroxyacetone in air or oxygen is greater than 70%, and the yield of carbon monoxide is greater than 95%.
[0021] Examples 14 - 21 (Dihydroxyacetone concentration): Except for the different dihydroxyacetone concentrations, other conditions are the same as in Example 4. The photolysis activity of dihydroxyacetone has a low correlation with its concentration. In a wide concentration range (0.01 - 2.5 mol / L), the yield of ethylene glycol after the photolysis of dihydroxyacetone is greater than 75%, and the yield of carbon monoxide is greater than 93%.
[0022] Table 1 Preparation of carbon monoxide and ethylene glycol by photolyzing dihydroxyacetone
[0023]
[0024]
[0025] Example 22:
[0026] A continuous flow synthesis of carbon monoxide and ethylene glycol was achieved by self-assembling a flow photoreactor. The device includes a 36W 254nm E27 UVC ultraviolet lamp, a spiral quartz tube, a peristaltic pump, two reagent bottles with lids and an air bag ( Figure 3 A in). The peristaltic pump continuously pushes the dihydroxyacetone solution into the spiral quartz reaction tube surrounding the ultraviolet lamp, and the dihydroxyacetone gradually undergoes a photolysis reaction to be converted into a carbon monoxide and ethylene glycol solution ( Figure 3 B in). Reaction conditions: 20 mM dihydroxyacetone, flow rate 0.2 mL / min. During the 1000h flow photolysis operation, the conversion rate of dihydroxyacetone at the outlet was detected to be 100%, the carbon monoxide yield was 96%, and the ethylene glycol yield was 80%. The carbon monoxide and ethylene glycol solutions at the outlet were collected in an air bag and a sealed reagent bottle respectively.
Claims
1. A method for producing carbon monoxide and ethylene glycol by photolysis of dihydroxyacetone, characterized in that, Using ultraviolet light as a light source, dihydroxyacetone is converted into carbon monoxide and ethylene glycol; The wavelength of the ultraviolet light source used is 200 nm - 340 nm; Dihydroxyacetone needs to be dissolved in a solvent for conversion; the solvent is one or more of water, methanol, ethanol, and acetonitrile.
2. The method for producing carbon monoxide and ethylene glycol by photolysis of dihydroxyacetone according to claim 1, wherein, The wavelength of the ultraviolet light source used is 250 nm - 310 nm.
3. A method for producing carbon monoxide and ethylene glycol by photolysis of dihydroxyacetone according to claim 1 or 2, characterized in that, The solvent described is water or a mixed solution of acetonitrile and water.
4. A method for producing carbon monoxide and ethylene glycol by photolysis of dihydroxyacetone according to claim 1 or 2, characterized in that, The molar concentration of dihydroxyacetone in the solvent is less than 2.5 M.
5. A method for producing carbon monoxide and ethylene glycol by photolysis of dihydroxyacetone according to claim 1 or 2, characterized in that, The molar concentration of dihydroxyacetone in the solvent is less than 1.0 M.
6. A method for producing carbon monoxide and ethylene glycol by photolysis of dihydroxyacetone according to claim 1 or 2, characterized in that, The atmosphere used for photolysis of dihydroxyacetone is vacuum or a mixture of one or more of argon, nitrogen, oxygen, air, carbon dioxide, and hydrogen.