A method for preparing ethylene glycol

Abstract

The present application discloses a method for preparing ethylene glycol, which comprises adding ethylene glycol monomethyl ether and water as reaction raw materials and a catalyst into a reactor in a predetermined ratio to perform a hydrolysis reaction at a predetermined pressure and a predetermined temperature to obtain ethylene glycol; wherein the catalyst is selected from at least one of an ionic liquid and an inorganic acid, the ionic liquid includes pyridine hydrochloride, triethylamine hydrochloride, and imidazole hydrochloride; the inorganic acid is selected from at least one of sulfuric acid, phosphoric acid, and nitric acid. The method is characterized in that ethylene glycol monomethyl ether and water are used as reaction raw materials, and a high yield of ethylene glycol can be produced, the process is simple, and it is a new method for synthesizing ethylene glycol.

Description

Technical Field

[0001] The present application relates to a method for preparing ethylene glycol, and belongs to the field of preparation and synthesis of ethylene glycol. Background Art

[0002] Ethylene glycol is an important chemical raw material and strategic material in China, mainly used to manufacture polyester, polyester resin, desiccant, plasticizer, surfactant, synthetic fiber and solvent, etc. At present, the production of ethylene glycol mainly adopts ethylene oxide hydration method, that is, ethylene from petroleum cracking is used as raw material, ethylene oxide is produced through oxidation reaction, and ethylene oxide is then hydrated to obtain ethylene glycol. However, in view of my country's energy structure of "rich in coal, poor in oil and little gas" and the current situation of crude oil prices maintaining high levels for a long time, the new chemical technology of coal-to-ethylene glycol is the most practical choice for the future coal chemical industry.

[0003] At present, the most mature coal-to-ethylene glycol technology in China is the "CO gas-phase catalytic synthesis of oxalate and oxalate catalytic hydrogenation synthesis of ethylene glycol complete process technology" developed by the Fujian Institute of Structure of Matter, Chinese Academy of Sciences. However, this technology has many process units, high industrial gas purity requirements, and the need to use precious metal catalysts in the oxidative coupling process, which restricts the economy, energy saving and further industrial scale-up of the process. In recent years, methyl methoxyacetate has attracted widespread attention as an important organic intermediate. It can be prepared by methylal gas phase carbonylation. Methyl methoxyacetate can be hydrogenated to produce ethylene glycol monomethyl ether, and ethylene glycol monomethyl ether can be hydrolyzed to produce ethylene glycol. A literature report introduces the relevant process of preparing ethylene glycol monomethyl ether by hydrolysis reaction. It uses a solid acid catalyst, mainly an acidic molecular sieve. This process is prone to the generation of by-products such as dimethyl ether and dioxane, and the molecular sieve catalyst is easily deactivated in the presence of water. There are also documents that use ethylene glycol monomethyl ether and halogens or halogenated hydrocarbons as raw materials to produce ethylene glycol. In this method, halogens or halogenated hydrocarbons participate in the reaction, and while ethylene glycol is produced, a large amount of halogenated alkanes are produced as by-products. Summary of the invention

[0004] In order to overcome the deficiencies in the prior art, the present application provides a method with high ethylene glycol yield and suitable for industrial application.

[0005] Specifically, the present application provides a method for preparing ethylene glycol, which comprises: adding ethylene glycol monomethyl ether and water as reaction raw materials, and a catalyst into a reactor in a predetermined proportion, so as to carry out a hydrolysis reaction at a predetermined pressure and a predetermined temperature to obtain ethylene glycol; wherein the catalyst is selected from at least one of an ionic liquid and an inorganic acid, the ionic liquid includes pyridine hydrochloride, triethylamine hydrochloride, and imidazole hydrochloride; the inorganic acid is selected from at least one of sulfuric acid, phosphoric acid, and nitric acid.

[0006] Optionally, the pyridine hydrochloride is selected from one of pyridine hydrochloride, 2-chloromethylpyridine hydrochloride, 5-ethyl-2-methylpyridine hydrochloride, 1-butylpyridine hydrochloride and 1-butyl-4-methylpyridinium chloride hydrochloride.

[0007] Optionally, the imidazole hydrochloride is selected from one of imidazole hydrochloride, 1-methylimidazole hydrochloride, 1-ethyl-3-methylimidazole hydrochloride, 1-butyl-3-methylimidazole hydrochloride and 4-hydroxymethylimidazole hydrochloride.

[0008] Optionally, the mass ratio of ethylene glycol monomethyl ether to water is ethylene glycol monomethyl ether: water = 1:0.5-20.

[0009] Optionally, the mass ratio of ethylene glycol monomethyl ether to water is selected from any value among 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:1, 1:1.5, 1:2, 1:3, 1:5, 1:7, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 and 1:20, or any range value between two of them.

[0010] Optionally, the mass ratio of ethylene glycol monomethyl ether to the catalyst is ethylene glycol monomethyl ether:catalyst=1:0.1-10.

[0011] Optionally, the mass ratio of ethylene glycol monomethyl ether to the catalyst is ethylene glycol monomethyl ether:catalyst=1:0.5-10.

[0012] Optionally, the mass ratio of ethylene glycol monomethyl ether to the catalyst is selected from any value among 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3.0, 1:3.5, 1:4.0, 1:4.5, 1:5.0, 1:5.5, 1:6.0, 1:6.5, 1:7.0, 1:7.5, 1:8.0, 1:8.5, 1:9.0, 1:9.5 and 1:10.0, or any range value between two of them.

[0013] Optionally, the conditions for the hydrolysis reaction are: reaction pressure of 0.1 to 5 MPa, reaction temperature of 70 to 200° C., and reaction time of 0.1 to 10 hours.

[0014] Optionally, the reaction pressure is selected from any value among 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.8 MPa, 1.0 MPa, 2.0 MPa, 3.0 MPa, 4.0 MPa and 5.0 MPa, or a range value between any two thereof.

[0015] Optionally, the reaction temperature is selected from any value among 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C and 200°C, or any range therebetween.

[0016] Optionally, the reaction time is selected from any value among 0.1h, 0.2h, 0.5h, 1.0h, 1.2h, 1.5h, 2.0h, 2.5h, 3.0h, 3.5h, 4.0h, 4.5h, 5.0h, 5.5h, 6.0h, 6.5h, 7.0h, 7.5h, 8.0h, 8.5h, 9.0h, 9.5h, 10.0h, or any range value between two thereof.

[0017] Optionally, the reactor is a corrosion-resistant high-pressure reactor.

[0018] Optionally, the corrosion-resistant high-pressure reactor is selected from at least one of a corrosion-resistant kettle reactor and a corrosion-resistant tubular reactor.

[0019] Optionally, the material of the corrosion-resistant high-pressure reactor is selected from one of glass lining, porcelain enamel, tetrafluoroethylene lining, Hastelloy material and titanium material.

[0020] The beneficial effects of this application include:

[0021] 1) The method for preparing ethylene glycol from ethylene glycol monomethyl ether provided in the present application can efficiently catalyze the conversion of ethylene glycol monomethyl ether, and the yield of ethylene glycol is relatively high, and the only by-product is methanol, which can be transported to the upstream methylal synthesis reactor for use as a raw material.

[0022] 2) The method for preparing ethylene glycol provided in the present application is simple, easy to operate, and has great industrial application prospects. DETAILED DESCRIPTION

[0023] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0024] The endpoints and any values ​​of the range disclosed in this application are not limited to the precise range or value, and these ranges or values ​​should be understood to include close to these ranges or values. For numerical ranges, the endpoint values ​​and individual point values ​​of each range can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0025] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0026] Unless otherwise specified, the raw materials and equipment in the examples of the present invention were purchased through commercial channels.

[0027] The analysis method in the examples of this application is as follows:

[0028] In the examples of the present application, the conversion rate of ethylene glycol monomethyl ether is calculated in the following manner:

[0029] The gas chromatographic peak area is obtained by configuring the ethylene glycol monomethyl ether content in the standard solution, and the peak area is used as the horizontal coordinate and the concentration of ethylene glycol monomethyl ether is used as the vertical coordinate to obtain a standard curve; further, the concentration of ethylene glycol monomethyl ether in the reaction solution after the reaction can be calculated, and the conversion rate of ethylene glycol monomethyl ether can be calculated through the concentration.

[0030] In the examples of the present application, the yield of ethylene glycol is calculated in the following manner:

[0031] The gas chromatographic peak area is obtained by configuring the ethylene glycol content in the standard solution, and the peak area is used as the horizontal coordinate and the concentration of ethylene glycol is used as the vertical coordinate to obtain a standard curve; further, the concentration of ethylene glycol in the reaction solution after the reaction can be calculated, and the yield of ethylene glycol can be calculated based on the concentration.

[0032] Example 1

[0033] 5 g of ethylene glycol monomethyl ether and 25 g of water, and 10 g of 1-methylimidazole hydrochloride as a catalyst were added into a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 3 MPa and a temperature of 200° C. for 0.1 hour. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 97%, the yield of ethylene glycol was 96%, and in this embodiment, the by-product was only methanol.

[0034] Example 2

[0035] 5 g of ethylene glycol monomethyl ether, 100 g of water, and 50 g of pyridine hydrochloride as a catalyst were added to a corrosion-resistant high-pressure reactor, and then reacted at 5 MPa pressure and 120° C. for 4 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 96%, the yield of ethylene glycol was 95%, and in this embodiment, the by-product was only methanol.

[0036] Example 3

[0037] 5 g of ethylene glycol monomethyl ether, 50 g of water, and 5 g of 1-butylpyridine hydrochloride as a catalyst were added to a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 1 MPa and a temperature of 100° C. for 6 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 98%, the yield of ethylene glycol was 96%, and in this embodiment, the by-product was only methanol.

[0038] Example 4

[0039] 5 g of ethylene glycol monomethyl ether, 10 g of water, and 2.5 g of triethylamine hydrochloride as a catalyst were added to a corrosion-resistant high-pressure reactor, and then reacted at 0.1 MPa pressure and 90° C. for 8 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 95%, the yield of ethylene glycol was 95%, and in this embodiment, the by-product was only methanol.

[0040] Example 5

[0041] 5 g of ethylene glycol monomethyl ether, 15 g of water, and 8 g of phosphoric acid as a catalyst were added to a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 0.1 MPa and a temperature of 70° C. for 10 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 85%, the yield of ethylene glycol was 83%, and in this embodiment, the by-product was only methanol.

[0042] Example 6

[0043] 5 g of ethylene glycol monomethyl ether, 20 g of water, and 5 g of sulfuric acid as a catalyst were added to a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 0.7 MPa and a temperature of 130° C. for 4 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 95%, the yield of ethylene glycol was 94%, and in this embodiment, the by-product was only methanol.

[0044] Example 7

[0045] 5 g of ethylene glycol monomethyl ether, 2.5 g of water, and 0.5 g of nitric acid as a catalyst were added into a corrosion-resistant high-pressure reactor, and then reacted at 0.1 MPa pressure and 80° C. for 8 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 88%, the yield of ethylene glycol was 87%, and in this embodiment, the byproduct was only methanol.

[0046] Example 8

[0047] 5 g of ethylene glycol monomethyl ether, 20 g of water, and 10 g of 2-chloromethylpyridine hydrochloride as a catalyst were added to a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 2 MPa and a temperature of 170° C. for 0.5 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 97%, the yield of ethylene glycol was 96%, and in this embodiment, the by-product was only methanol.

[0048] Example 9

[0049] 5 g of ethylene glycol monomethyl ether, 15 g of water, and 20 g of 5-ethyl-2-methylpyridine hydrochloride as a catalyst were added into a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 1.2 MPa and a temperature of 180° C. for 1 hour. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 98%, the yield of ethylene glycol was 98%, and in this embodiment, the by-product was only methanol.

[0050] Example 10

[0051] 5 g of ethylene glycol monomethyl ether, 25 g of water, and 5 g of 1-butyl-4-methylpyridinium chloride hydrochloride as a catalyst were added into a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 3 MPa and a temperature of 200° C. for 0.2 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 97%, the yield of ethylene glycol was 96%, and in this embodiment, the by-product was only methanol.

[0052] Embodiment 11

[0053] 5 g of ethylene glycol monomethyl ether and 40 g of water, and 40 g of 1-ethyl-3-methylimidazole hydrochloride as a catalyst were added into a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 2.5 MPa and a temperature of 160° C. for 2 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 95%, the yield of ethylene glycol was 95%, and in this embodiment, the by-product was only methanol.

[0054] Example 12

[0055] 5 g of ethylene glycol monomethyl ether, 10 g of water, and 30 g of 1-butyl-3-methylimidazole hydrochloride as a catalyst were added into a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 0.5 MPa and a temperature of 140° C. for 6 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 93%, the yield of ethylene glycol was 92%, and in this embodiment, the by-product was only methanol.

[0056] Example 13

[0057] 5 g of ethylene glycol monomethyl ether, 25 g of water, and 10 g of 4-hydroxymethylimidazole hydrochloride as a catalyst were added into a corrosion-resistant high-pressure reactor, and then reacted at 3 MPa pressure and 190° C. for 1 hour. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 95%, the yield of ethylene glycol was 95%, and in this embodiment, the by-product was only methanol.

[0058] Embodiment 14

[0059] 5 g of ethylene glycol monomethyl ether, 50 g of water, and 50 g of imidazole hydrochloride as a catalyst were added to a corrosion-resistant high-pressure reactor, and then reacted at a pressure of 5 MPa and a temperature of 200° C. for 0.2 hours. Gas chromatography analysis and calculation showed that the conversion rate of ethylene glycol monomethyl ether was 97%, the yield of ethylene glycol was 96%, and in this embodiment, the by-product was only methanol.

[0060] The corrosion-resistant high-pressure reactor used in the above embodiments of the present application is a corrosion-resistant kettle reactor. Of course, the present application is not limited to this reactor, and any other suitable reactor can be used.

[0061] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing ethylene glycol, characterized in that: The method comprises: adding ethylene glycol monomethyl ether and water as reaction raw materials and a catalyst into a reactor in a predetermined ratio to perform a hydrolysis reaction at a predetermined pressure and a predetermined temperature to obtain ethylene glycol; Wherein, the catalyst is selected from at least one of ionic liquids and inorganic acids, the ionic liquids include pyridine hydrochloride, triethylamine hydrochloride, and imidazole hydrochloride; the inorganic acid is selected from at least one of sulfuric acid, phosphoric acid, and nitric acid; The pyridine hydrochloride is selected from one of pyridine hydrochloride, 2-chloromethyl pyridine hydrochloride, 5-ethyl-2-methyl pyridine hydrochloride, 1-butyl pyridine hydrochloride and 1-butyl-4-methyl pyridinium chloride hydrochloride; The imidazole hydrochloride is selected from one of imidazole hydrochloride, 1-methylimidazole hydrochloride, 1-ethyl-3-methylimidazole hydrochloride, 1-butyl-3-methylimidazole hydrochloride and 4-hydroxymethylimidazole hydrochloride; The conditions of the hydrolysis reaction are: reaction pressure of 0.1-5 MPa, reaction temperature of 70-200° C., and reaction time of 0.1-10 hours.

2. The method according to claim 1, characterized in that The mass ratio of ethylene glycol monomethyl ether and water is ethylene glycol monomethyl ether: water = 1: 0.5~20.

3. The method according to claim 1, characterized in that The mass ratio of ethylene glycol monomethyl ether to the catalyst is ethylene glycol monomethyl ether: catalyst = 1: 0.1-10.

4. The method according to claim 1, characterized in that The mass ratio of ethylene glycol monomethyl ether to the catalyst is ethylene glycol monomethyl ether: catalyst = 1: 0.5-10.

5. The method according to claim 1, characterized in that The reactor is a corrosion-resistant high-pressure reactor.

6. The method according to claim 5, characterized in that The corrosion-resistant high-pressure reactor is selected from at least one of a corrosion-resistant kettle reactor and a corrosion-resistant tubular reactor.

7. The method according to claim 5, characterized in that The material of the corrosion-resistant high-pressure reactor is selected from one of glass lining, porcelain enamel, tetrafluoroethylene lining, Hastelloy material and titanium material.