Method for preparing vinyl acetate from ethylene glycol
By reacting ethylene glycol with acetic anhydride under an acid catalyst, vinyl acetate is prepared, which solves the problem of vinyl acetate production relying on fossil energy, and achieves efficient, green and environmentally friendly vinyl acetate preparation, which enhances the industrial competitiveness of ethylene glycol.
Patent Information
- Application Number
- CN202510633860.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-16
- Publication Date
- 2025-08-19
AI Technical Summary
In the prior art, the production of vinyl acetate depends on fossil energy, resulting in energy problems and carbon emissions. The downstream utilization of ethylene glycol is insufficient, and it is necessary to develop efficient, green and environmentally friendly preparation methods.
Ethylene acetate is prepared by reacting ethylene glycol and acetic anhydride in the presence of an acid catalyst, with a reaction temperature of 120-200°C and a reaction time of 12 hours.
It has achieved the use of biomass ethylene glycol as the raw material, the catalyst can be recycled, the process is simple, the product vinyl acetate yield is high, and it has industrial prospects.
Smart Images
Figure CN120504596A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of organic synthesis, and in particular to a method for preparing vinyl acetate from ethylene glycol. Background Art
[0002] Vinyl acetate is an important industrial monomer. Polyvinyl acetate, polyvinyl alcohol, and vinyl acetate-ethylene copolymers (EVA) produced from it have important applications in the textile, light industry, electronics, and synthetic fiber industries. Industrially, vinyl acetate is produced through the reaction of acetylene (or acetic acid) with oxygen, largely relying on fossil energy. To alleviate energy constraints and reduce carbon emissions, developing biomass-based routes to produce vinyl acetate has significant scientific and practical applications.
[0003] Ethylene glycol, a common chemical raw material, can be produced through a one-step catalytic conversion of cellulose or straw sugar, with production already reaching thousands of tons. Furthermore, the production of ethylene glycol from coal via synthesis gas is a crucial component of my country's modern coal chemical industry. Since the initial industrialization of coal-to-ethylene glycol technology, production capacity has reached 5 million tons, currently experiencing overcapacity. There is an urgent need to explore high-value downstream utilization pathways for ethylene glycol, enhance the competitiveness of the ethylene glycol industry, and foster its sustainable and healthy development. Summary of the Invention
[0004] The present invention aims to provide a method for preparing vinyl acetate from ethylene glycol. The method has a simple reaction process, the raw material ethylene glycol can be derived from biomass, the raw material is cheap and easily available, and the catalytic system is efficient and environmentally friendly.
[0005] To achieve the above-mentioned object, the present invention is implemented through the following technical solutions:
[0006] A method for preparing vinyl acetate from ethylene glycol comprises the following specific steps: dissolving ethylene glycol and acetic anhydride in a solvent, then adding an acid catalyst, and stirring at a certain temperature to prepare vinyl acetate; the reaction temperature is 120-200° C., and the reaction time is 12 hours; the acid catalyst is one of sulfuric acid, carboxylic acid, trifluoromethanesulfonic acid, trifluoroacetic acid, p-toluenesulfonic acid, ion exchange resin Amberlyst-15, and Nafion resin; and the carboxylic acid is one of formic acid, acetic acid, lactic acid, succinic acid, and adipic acid.
[0007] Preferably, the molar ratio of ethylene glycol to acetic anhydride is 5:1; and the mass ratio of the acid catalyst to acetic anhydride is 0.31:1.
[0008] Preferably, the reaction temperature is 200°C.
[0009] Preferably, when the acid catalyst is one of sulfuric acid, trifluoromethanesulfonic acid, trifluoroacetic acid, p-toluenesulfonic acid, ion exchange resin Amberlyst-15, and Nafion resin, the solvent is one of dichloroethane, N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, and tetrabutylammonium acetate.
[0010] Preferably, when the acid catalyst is one of sulfuric acid, trifluoromethanesulfonic acid, trifluoroacetic acid, p-toluenesulfonic acid, ion exchange resin Amberlyst-15, and Nafion resin, the solvent is a mixed solvent of choline chloride and ethylene glycol or a mixed solvent of choline chloride and glycerol.
[0011] Preferably, when the acid catalyst is carboxylic acid, the solvent is a mixed solvent of choline chloride and carboxylic acid as the acid catalyst.
[0012] Preferably, the molar concentration of acetic anhydride is 0.01-1.0M.
[0013] The vinyl acetate synthesis route provided by the present invention is environmentally friendly. It uses renewable ethylene glycol as a starting material, uses a recyclable acid catalyst, is highly efficient, and has a simple process. Therefore, the present method represents a promising biomass-based route for synthesizing vinyl acetate. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 This is the GC spectrum of vinyl acetate obtained in Example 23;
[0015] Figure 2 This is the MS spectrum of vinyl acetate obtained in Example 23;
[0016] Figure 3 The vinyl acetate obtained in Example 23 1 H-NMR spectrum;
[0017] Figure 4 The vinyl acetate obtained in Example 23 13 C-NMR spectrum. DETAILED DESCRIPTION
[0018] The present invention will be further described in detail below with reference to the embodiments.
[0019] In the following examples, unless otherwise stated, all reagents used can be purchased from commercial sources or obtained according to known literature reports.
[0020] Example 1
[0021] A method for preparing vinyl acetate from ethylene glycol comprises the following steps: adding acetic anhydride (1 mmol, 0.1 g) and ethylene glycol (5 mmol, 0.31 g) to acetic anhydride under the catalysis of sulfuric acid H2SO4 (30 wt%, 31 mg), adding ethylene dichloride (2 mL), reacting at 160°C for 12 hours to generate vinyl acetate; adding internal standard n-tridecane for detection after the reaction, and gas chromatography analysis shows that the yield of vinyl acetate is 21%.
[0022] Example 2
[0023] "N,N-dimethylformamide" was used to replace "dichloroethane" in Example 1. Other processes remained the same as in Example 1. The yield of vinyl acetate was 24%.
[0024] Example 3
[0025] N-methylpyrrolidone was used to replace the dichloroethane in Example 1. The other processes remained the same as in Example 1. The yield of vinyl acetate was 31%.
[0026] Example 4
[0027] "Dimethyl sulfoxide" was used to replace "dichloroethane" in Example 1. Other processes remained the same as in Example 1. The yield of vinyl acetate was 29%.
[0028] Example 5
[0029] "1-ethyl-3-methylimidazolium chloride" was used instead of "dichloroethane" in Example 1. Other processes remained the same as in Example 1. The yield of vinyl acetate obtained was 46%.
[0030] Example 6
[0031] "1-ethyl-3-methylimidazolium bromide" was used to replace "dichloroethane" in Example 1. Other processes remained the same as in Example 1. The yield of vinyl acetate obtained was 52%.
[0032] Example 7
[0033] The "dichloroethane" in Example 1 was replaced by "1-ethyl-3-methylimidazolium acetate" and the other processes remained the same as in Example 1. The yield of the obtained vinyl acetate was 31%.
[0034] Example 8
[0035] "1-Butyl-3-methylimidazolium chloride" was used instead of "dichloroethane" in Example 1. Other processes remained the same as in Example 1. The yield of vinyl acetate was 54%.
[0036] Example 9
[0037] Tetrabutylammonium chloride was used instead of dichloroethane in Example 1. Other processes remained the same as in Example 1. The yield of vinyl acetate was 36%.
[0038] Example 10
[0039] Tetrabutylammonium bromide was used to replace the dichloroethane in Example 1. The other processes remained the same as in Example 1. The yield of vinyl acetate was 41%.
[0040] Example 11
[0041] Tetrabutylammonium acetate was used instead of dichloroethane in Example 1. Other processes remained the same as in Example 1. The yield of vinyl acetate was 23%.
[0042] Example 12
[0043] The "ethylene dichloride" in Example 1 was replaced by "choline chloride and ethylene glycol (the molar ratio between the two was 1:1)". The other processes remained the same as in Example 1. The yield of vinyl acetate was 23%.
[0044] Example 13
[0045] The "ethylene dichloride" in Example 1 was replaced by "choline chloride and glycerol (the molar ratio between the two was 1:1)". The other processes remained the same as in Example 1. The yield of vinyl acetate was 23%.
[0046] Example 14
[0047] A method for preparing vinyl acetate from ethylene glycol comprises the following specific steps: heating choline chloride and formic acid in a molar ratio of 1:1 to prepare 2 mL of an ionic liquid as a solvent; then adding acetic anhydride (1 mmol, 0.1 g) and ethylene glycol (5 mmol, 0.31 g), with the formic acid serving not only as a solvent but also as an acid catalyst; reacting at 160° C. for 12 hours to generate vinyl acetate; and adding internal standard n-tridecane for detection after the reaction. Gas chromatography analysis shows that the yield of vinyl acetate is 39%.
[0048] Example 15
[0049] The “choline chloride and acetic acid (the molar ratio between the two is 1:1)” in Example 14 was replaced by “choline chloride and acetic acid (the molar ratio between the two is 1:1)”. The other processes remained the same as in Example 14. The yield of vinyl acetate was 45%.
[0050] Example 16
[0051] The "choline chloride and formic acid (the molar ratio between the two is 1:1)" in Example 14 was replaced by "choline chloride and lactic acid (the molar ratio between the two is 1:1)". The other processes remained the same as in Example 14, and the yield of vinyl acetate was 40%.
[0052] Example 17
[0053] The reaction mixture in Example 14 was replaced by choline chloride and succinic acid (the molar ratio between the two was 1:1) while the other steps were the same as those in Example 14. The yield of vinyl acetate was 36%.
[0054] Example 18
[0055] The reaction mixture in Example 14 was replaced by choline chloride and adipic acid (the molar ratio between the two was 1:1) while the other steps were the same as those in Example 14. The yield of vinyl acetate was 31%.
[0056] Example 19
[0057] In this embodiment, the reaction temperature is 120° C., and the other steps are the same as those in Example 8; the yield of vinyl acetate is 31%.
[0058] Example 20
[0059] In this embodiment, the reaction temperature is 140° C., and the other steps are the same as those in Example 8; the yield of vinyl acetate is 41%.
[0060] Example 21
[0061] In this embodiment, the reaction temperature is 180° C., and the other steps are the same as those in Example 8; the yield of vinyl acetate is 61%.
[0062] Example 22
[0063] In this embodiment, the reaction temperature is 200° C., and the other steps are the same as those in Example 8; the yield of the obtained vinyl acetate is 70%.
[0064] Example 23
[0065] A method for preparing vinyl acetate from ethylene glycol comprises the following steps: adding (1.25 g) of 1-butyl-3-methylimidazolium chloride to acetic anhydride (1 mmol, 0.1 g) and ethylene glycol (5 mmol, 0.31 g) under the catalysis of trifluoromethanesulfonic acid (30 wt %, 31 mg), reacting at 200° C. for 12 h to generate vinyl acetate; adding internal standard n-tridecane for detection after the reaction, such as Figure 1As shown, after gas chromatography analysis, the yield of vinyl acetate was 76%.
[0066] The MS pattern of the product obtained in this step is as follows Figure 2 As shown, from Figure 2 It can be seen that the relative molecular mass of the prepared product is consistent with that of vinyl acetate.
[0067] The product obtained in this step 1 H-NMR spectrum Figure 3 As shown, the spectrum data: 1 H NMR (600MHz, CHLOROFORM-D) δ7.19,7.18,7.17,7.16,4.79,4.79,4.76,4.47,4.46,2.03.; 13 C-NMR spectrum Figure 4 As shown, the spectrum data: 13 C NMR (151MHz, CHLOROFORM-D) δ167.83,141.16,97.42,20.50.
[0068] pass Figure 1-4 , which verifies that vinyl acetate was successfully prepared in this example.
[0069] Example 24
[0070] "P-toluenesulfonic acid" was used instead of "trifluoromethanesulfonic acid" in Example 23. The other processes remained the same as in Example 23. The yield of vinyl acetate was 41%.
[0071] Example 25
[0072] "Trifluoroacetic acid" was used instead of "trifluoromethanesulfonic acid" in Example 23. Other processes remained the same as in Example 23. The yield of vinyl acetate obtained was 36%.
[0073] Example 26
[0074] "Ion exchange resin Amberlyst-15" was used instead of "trifluoromethanesulfonic acid" in Example 23. Other processes remained the same as in Example 23. The yield of vinyl acetate obtained was 41%.
[0075] Example 27
[0076] "Nafion resin" was used instead of "trifluoromethanesulfonic acid" in Example 23. Other processes remained the same as in Example 23. The yield of vinyl acetate was 51%.
[0077] The above examples demonstrate that the reaction medium significantly influences the selectivity of the dehydration reaction using sulfuric acid as a catalyst. In nonpolar solvents, the yield of the target product, vinyl acetate, is low; in highly polar solvents such as DMSO and NMP, the yield is improved. To further increase the solvent polarity, a green ionic liquid was selected as the reaction medium. In the [Emim]Cl ionic liquid solvent, the yield of vinyl acetate was 46%. Other types of ligand anions resulted in reduced product yields. Increasing the length of the alkyl group on the imidazole ring to butyl ([Bmim]Cl) increased the yield of the target product to 54%. The above examples also explored the effect of a biomass-derived choline chloride (ChCl)-based deep eutectic solvent (DES). Screening various carboxylic acids revealed that most acidic deep eutectic solvents promoted the reaction, but the overall yield was inferior to that of the ionic liquid [Bmim]Cl. Temperature screening revealed that a 12-hour reaction at 200°C resulted in a 70% yield, although polymer formation was also observed. Through catalyst optimization, it was found that trifluoromethanesulfonic acid TfOH had higher catalytic activity, while solid acids such as Amberlyst-15 and Nafion had lower activity.
Claims
1. A method for preparing vinyl acetate from ethylene glycol, characterized in that: The specific steps are: dissolving ethylene glycol and acetic anhydride in a solvent, then adding an acid catalyst, and stirring at a certain temperature to prepare vinyl acetate; the reaction temperature is 120-200°C, and the reaction time is 12 hours; the acid catalyst is one of sulfuric acid, carboxylic acid, trifluoromethanesulfonic acid, trifluoroacetic acid, p-toluenesulfonic acid, ion exchange resin Amberlyst-15, and Nafion resin; and the carboxylic acid is one of formic acid, acetic acid, lactic acid, succinic acid, and adipic acid.
2. The method for preparing vinyl acetate from ethylene glycol according to claim 1, wherein: The molar ratio of ethylene glycol to acetic anhydride is 5:1; the mass ratio of the acid catalyst to acetic anhydride is 0.31:
1.
3. The method for preparing vinyl acetate from ethylene glycol according to claim 1, characterized in that: The reaction temperature is 200°C.
4. The method for preparing vinyl acetate from ethylene glycol according to claim 1, characterized in that: When the acid catalyst is one of sulfuric acid, trifluoromethanesulfonic acid, trifluoroacetic acid, p-toluenesulfonic acid, ion exchange resin Amberlyst-15, and Nafion resin, the solvent is one of dichloroethane, N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, and tetrabutylammonium acetate.
5. The method for preparing vinyl acetate from ethylene glycol according to claim 1, characterized in that: When the acid catalyst is one of sulfuric acid, trifluoromethanesulfonic acid, trifluoroacetic acid, p-toluenesulfonic acid, ion exchange resin Amberlyst-15, and Nafion resin, the solvent is a mixed solvent of choline chloride and ethylene glycol or a mixed solvent of choline chloride and glycerol.
6. The method for preparing vinyl acetate from ethylene glycol according to claim 1, characterized in that: When the acid catalyst is carboxylic acid, the solvent is a mixed solvent of choline chloride and the carboxylic acid serving as the acid catalyst.
7. The method for preparing vinyl acetate from ethylene glycol according to claim 1, characterized in that: The molar concentration of acetic anhydride is 0.01-1.0M.