A process for the preparation of diethylene glycol

Abstract

The application discloses a preparation method of diethylene glycol, which comprises the following steps: contacting ethylene glycol with a catalyst, and reacting to obtain the diethylene glycol; the catalyst is SO4 2‑ / ZnFeO4-ZrO2 obtained by impregnating the surface of ZnFeO4 loaded with ZrO2 with sulfuric acid. The catalyst provided by the application is applied to a diethylene glycol dehydration reaction for preparing diethylene glycol, so as to improve the conversion rate of ethylene glycol and the selectivity of the generated diethylene glycol.

Description

Technical Field

[0001] This application relates to a method for preparing diethylene glycol, which belongs to the field of chemical engineering. Background Technology

[0002] Diethylene glycol (DEG, structural formula HOCH3CH3OCH3CH3OH) and triethylene glycol (TEG, structural formula HOCH3CH3OCH3CH3OCH3CH3OH) are oligomeric polyethylene glycols mainly used as solvents, gas dehydrating agents, aromatic hydrocarbon separation and extraction agents, textile softeners, and finishing agents for various applications. They are also used as antifreeze components in brake fluids and compressor lubricating oils, and in the formulation of cleaning agents. Furthermore, oligomeric diethylene glycol molecules contain both ether bonds and hydroxyl groups, giving them unique physicochemical properties. They are widely used in the preparation of various chemicals such as rubber and resin plasticizers, polyester resins, fiberglass, and urethane foams, and are important raw materials for the petrochemical, rubber, plastics, textile, coating, and adhesive industries.

[0003] Currently, diethylene glycol and triethylene glycol in China are only derived from byproducts of ethylene glycol production via the hydration of ethylene oxide (EO). Diethylene glycol accounts for approximately 9% and triethylene glycol approximately 1% of these byproducts. Furthermore, ethylene oxide is flammable, explosive, and classified as a Group 1 carcinogen, making it unsuitable for storage and transportation; the process is also lengthy, energy-intensive, and difficult to control in terms of reaction depth. Therefore, the application of methods for preparing oligomeric polyethylene glycol from ethylene oxide as a starting material has been limited. The technology for preparing diethylene glycol through ethylene glycol dehydration shows promising industrial application prospects.

[0004] As is well known, protic acids, which are mainly used in traditional industries, have disadvantages such as corrosiveness and toxicity. When used in the dehydration reaction of ethylene glycol, they not only cause great corrosion to equipment, but also cause serious side reactions. At the same time, the large amount of waste acid and wastewater generated by this method is difficult to treat, which not only increases industrial costs, but also wastes some resources.

[0005] Literature reports on solid acid catalysts for the catalytic dehydration of ethylene glycol are still relatively few. Solid acid catalysts have become a focus of research due to their high activity, high selectivity, and ease of separation. With technological advancements and increased environmental awareness, solid acid catalysts, which offer advantages such as recyclability and reusability, are gradually replacing traditional proton acid catalysts in chemical production. Summary of the Invention

[0006] This application prepares SO4 2- The application of the ZnFeO4-ZrO2 catalyst in the preparation of diethylene glycol is of great significance. The catalyst has good activity, high ethylene glycol conversion and diethylene glycol selectivity, and good stability.

[0007] According to one aspect of this application, a method for preparing diethylene glycol is provided, the method comprising:

[0008] Ethylene glycol is reacted with a catalyst to obtain the diethylene glycol;

[0009] The catalyst is SO4. 2- / ZnFeO4-ZrO2.

[0010] Optionally, the SO4 2- / ZnFeO4-ZrO2 is obtained by impregnating ZnFeO4 with ZrO2 on the surface with sulfuric acid.

[0011] Optionally, the catalyst preparation method includes: preparing ZnFeO4 by high-temperature calcination, loading ZrO2 onto the surface of ZnFeO4 by impregnation, and preferably impregnating with H2SO4 solution to obtain the catalyst.

[0012] Optionally, the SO4 2- The preparation method of / ZnFeO4-ZrO2 includes the following steps:

[0013] (1) A mixture containing zinc source, iron source and solvent I is dried and calcined to obtain ZnFeO4;

[0014] (2) A mixture containing zirconium source, ZnFeO4 and solvent II is dried and calcined to obtain ZnFeO4-ZrO2;

[0015] (3) ZnFeO4-ZrO2 was impregnated with H2SO4 solution, dried (III), and calcined (III) to obtain the SO4. 2- / ZnFeO4-ZrO2.

[0016] Optionally, the zinc source is selected from at least one of zinc nitrate, zinc sulfate, and zinc oxide.

[0017] Optionally, the iron source is selected from at least one of ferric nitrate, ferric sulfate, and ferric oxide.

[0018] Optionally, the zirconium source is selected from zirconium sulfate and / or zirconium nitrate.

[0019] Optionally, in step (1), the molar ratio of the zinc source to the iron source is (0.9-2):1.

[0020] Optionally, the molar ratio of the zinc source to the iron source is selected from any value among 0.9:1, 1:1, 1.9:1, 2:1, or any range between the two.

[0021] Optionally, solvent I is selected from at least one of methanol, ethanol, and acetone.

[0022] Optionally, the temperature of drying I is 80–110°C, and the drying time is 2–5 hours.

[0023] Optionally, the temperature of the drying I is selected from any value of 80°C, 90°C, 100°C, 110°C, or a range between any two of the above.

[0024] Optionally, the drying time I is selected from any value of 2h, 3h, 4h, 5h or a range between any two of the above.

[0025] Optionally, the calcination temperature I is 600–1200°C, and the calcination time I is 4–8 hours.

[0026] Optionally, the calcination temperature I is selected from any value of 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃, 1200℃ or a range between any two of the above.

[0027] Optionally, the calcination time I is selected from any value of 4h, 5h, 6h, 7h, 8h or a range between any two of the above.

[0028] Optionally, in step (2), the mass ratio of ZnFeO4 to ZrO2 in ZnFeO4-ZrO2 is 100:(3-20).

[0029] Optionally, the mass ratio of ZnFeO4 to the supported ZrO2 is 100:(3-20).

[0030] Optionally, the mass ratio of ZnFeO4 to the loaded ZrO2 is selected from any value of 100:3, 100:5, 100:7, 100:9, 100:11, 100:13, 100:15, 100:18, 100:20 or a range between any two of the above.

[0031] Optionally, solvent II is selected from ethanol and / or water.

[0032] Optionally, the temperature of the drying process II is 80–110°C, and the drying time is 2–5 hours.

[0033] Optionally, the temperature of the drying II is selected from any value of 80°C, 90°C, 100°C, 110°C, or a range between any two of the above.

[0034] Optionally, the drying time II is selected from any value of 2h, 3h, 4h, 5h or a range between any two of the above.

[0035] Optionally, the calcination temperature II is 500–600°C, and the calcination time II is 4–8 hours.

[0036] Optionally, the calcination temperature II is selected from any value of 500°C, 550°C, 600°C, or a range between any two of the above.

[0037] Optionally, the calcination time II is selected from any value of 4h, 5h, 6h, 7h, 8h or a range between any two of the above.

[0038] Optionally, in step (3), the solid-liquid ratio of the ZnFeO4-ZrO2 to the H2SO4 solution is 1:20-30 g / ml.

[0039] Optionally, the solid-liquid ratio of the ZnFeO4-ZrO2 to H2SO4 solution is selected from any value among 1:20 g / ml, 1:25 g / ml, 1:30 g / ml, or any range between the two.

[0040] Optionally, the concentration of the H2SO4 solution is 0.1–2 M.

[0041] Optionally, the concentration of the H2SO4 solution is selected from any value among 0.1M, 0.3M, 0.5M, 0.7M, 0.9M, 1.1M, 1.3M, 1.5M, 1.7M, and 2.0M, or a range between any two of the above.

[0042] Optionally, the soaking time is 4 to 24 hours.

[0043] Optionally, the soaking time is any value among 4h, 8h, 12h, 16h, 20h, and 24h, or a range between any two of the above.

[0044] Optionally, in step (3), the temperature of drying III is 80-110°C, and the drying time of drying III is 2-5 hours.

[0045] Optionally, the temperature of the drying III is selected from any value of 80°C, 90°C, 100°C, 110°C, or a range between any two of the above.

[0046] Optionally, the drying time III is selected from any value of 2h, 3h, 4h, 5h or a range between any two of the above;

[0047] Optionally, the temperature of calcination III is 400–600°C, and the calcination time of calcination III is 3–6 hours.

[0048] Optionally, the calcination temperature III is selected from any value of 400℃, 450℃, 500℃, 550℃, 600℃ or a range between any two of the above.

[0049] Optionally, the calcination time III is selected from any value of 3h, 4h, 5h, 6h or a range between any two of the above.

[0050] Optionally, the reaction temperature is 80–200°C.

[0051] Optionally, in the reaction, the N2 flow rate is 0-30 ml / min.

[0052] Optionally, in the reaction, the N2 flow rate is selected from any value of 0 ml / min, 5 ml / min, 10 ml / min, 15 ml / min, 20 ml / min, 25 ml / min, 30 ml / min, or a range between any two of the above.

[0053] Optionally, the mass hourly space velocity (HHSV) of the reaction is 0.2–2 h⁻¹. -1 .

[0054] Optionally, the mass hourly space velocity (HHSV) of the reaction is 0.2 h⁻¹. -1 0.4h -1 0.6h -1 0.8h -1 1.0h -1 1.2h -1 1.4h -1 1.6h -1 1.8h -1 2.0h -1 Any value in or a range between any two of the above.

[0055] The beneficial effects that this application can produce include:

[0056] 1) The catalyst provided in this application can be applied to the dehydration reaction of ethylene glycol to prepare diethylene glycol, and improves the conversion rate of ethylene glycol and the selectivity of the generated diethylene glycol.

[0057] 2) The preparation method of the catalyst provided in this application is stable, controllable, and reproducible.

[0058] 3) The method for preparing diethylene glycol by dehydration of ethylene glycol provided in this application uses the catalyst provided in this application, which has a fast reaction rate and high yield, and can be applied to large-scale production. Attached Figure Description

[0059] Figure 1 Catalyst 1 in Example 1 of this application # Result 4 of the reaction# A combination of images depicting different temperaments. Detailed Implementation

[0060] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0061] Unless otherwise specified, the raw materials and catalysts used in the embodiments of this application were all purchased commercially.

[0062] The gas chromatograph used was an Agilent 7890B gas chromatograph.

[0063] In the embodiments of this application, the conversion rate and selectivity are calculated as follows:

[0064] The conversion rate and selectivity calculation formulas in the embodiments of this application are as follows (using ethylene glycol conversion rate as the evaluation index):

[0065] Ethylene glycol conversion rate = (initial carbon number of ethylene glycol - carbon number of ethylene glycol in the product) * 100 / initial carbon number of ethylene glycol.

[0066] Diethylene glycol selectivity = number of carbon atoms in diethylene glycol * 100 / ∑(number of carbon atoms in diethylene glycol + number of carbon atoms in other products).

[0067] Example 1

[0068] Taking item 1 in Tables 1-3 as an example, zinc nitrate and ferric nitrate with a molar ratio of 1:1 were mixed in an ethanol solution, ultrasonicated, ground, and dried in an oven at 100℃ for 4 hours; then calcined in a high-temperature furnace at 1000℃ for 4 hours to obtain ZnFeO4. Zirconium sulfate, ZnFeO4, and deionized water were mixed and stirred (ZnFeO4 to loaded ZrO2 mass ratio of 100:15), dried in an oven at 100℃ for 4 hours, and then calcined at 500℃ for 4 hours to obtain ZnFeO4-ZrO2. ZnFeO4-ZrO2 was impregnated with 0.5M H2SO4 solution (solid-liquid ratio 1:20 g / ml) for 8 hours, filtered, dried in an oven at 100℃ for 4 hours, and then calcined at 500℃ for 3 hours to obtain SO4. 2- / ZnFeO4-ZrO2, denoted as catalyst 1 # .

[0069] Table 1

[0070]

[0071]

[0072] Table 2

[0073]

[0074]

[0075] The columns in Tables 1 and 2 above are explained as follows:

[0076] Zinc sources: zinc nitrate (Zn1), zinc sulfate (Zn2), zinc oxide (Zn3).

[0077] Iron sources: ferric nitrate (Fe1), ferric sulfate (Fe2), ferric oxide (Fe3).

[0078] Solvent I: Methanol (solution 1), ethanol (solution 2), acetone (solution 3).

[0079] Zirconium source: Zirconium sulfate (Zr1), Zirconium nitrate (Zr2).

[0080] Solvent II: Ethanol (solution 2), deionized water (solution 4).

[0081] Drying I: Drying during the preparation of ZnFeO4.

[0082] Drying II: Drying during the preparation of ZrO2-ZnFeO4.

[0083] Calcination I: Calcination during the preparation of ZnFeO4.

[0084] Calcination II: Calcination during the preparation of ZrO2-ZnFeO4.

[0085] Table 3

[0086]

[0087]

[0088]

[0089] The explanations for each column in Table 3 above are as follows:

[0090] Drying III: Preparation of SO4 2- Drying during the ZrO2-ZnFeO4 process.

[0091] Calcination III: Preparation of SO4 2- Calcination during the ZrO2-ZnFeO4 process.

[0092] Comparative Example 1

[0093] Zinc nitrate and ferric nitrate in a molar ratio of 1:1 were mixed in an ethanol solution, ultrasonicated, and then ground together. The mixture was dried in an oven at 100°C for 4 hours, and then calcined in a high-temperature furnace at 1000°C for 4 hours to obtain ZnFeO4. Zirconium sulfate, ZnFeO4, and deionized water were mixed and stirred (ZnFeO4 to supported ZrO2 mass ratio of 100:15), dried in an oven at 100°C for 4 hours, and then calcined at 500°C for 4 hours to obtain ZnFeO4-ZrO2.

[0094] Example 2

[0095] Catalyst 1 prepared in Example 1 # The catalyst prepared in Comparative Example 1 was used to dehydrate ethylene glycol to prepare diethylene glycol. Reaction parameters were varied, and after the reaction stabilized (6 hours), both the reactants and products were analyzed using online gas chromatography. The composition of the ethylene glycol dehydration reaction products was analyzed using an Agilent 7890B gas chromatograph (FID detector, FFAP capillary column). The reaction results are shown in Table 4.

[0096] Table 4

[0097]

[0098]

[0099] Figure 1 Catalyst 1 of this application # Result 4 of the reaction # A combination of temperament images, from Figure 1 It can be seen that the main product, diethylene glycol, has high selectivity, while the byproducts are all known substances.

[0100] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing diethylene glycol, characterized in that, The preparation method includes: Ethylene glycol is reacted with a catalyst to obtain the diethylene glycol; The catalyst is SO4. 2- / ZnFeO4-ZrO2; The SO4 2- / ZnFeO4-ZrO2 is obtained by impregnating ZnFeO4 with ZrO2 on the surface with sulfuric acid.

2. The preparation method according to claim 1, characterized in that, The SO4 2- The preparation method of / ZnFeO4-ZrO2 includes the following steps: (1) A mixture containing zinc source, iron source and solvent I is dried and calcined to obtain ZnFeO4; (2) A mixture containing zirconium source, ZnFeO4 and solvent II is dried and calcined to obtain ZnFeO4-ZrO2; (3) ZnFeO4-ZrO2 was impregnated with H2SO4 solution, dried (III), and calcined (III) to obtain the SO4. 2- / ZnFeO4-ZrO2.

3. The preparation method according to claim 2, characterized in that, The zinc source is selected from at least one of zinc nitrate, zinc sulfate, and zinc oxide; The iron source is selected from at least one of ferric nitrate, ferric sulfate, and ferric oxide; The zirconium source is selected from zirconium sulfate and / or zirconium nitrate.

4. The preparation method according to claim 2, characterized in that, In step (1), the molar ratio of the zinc source to the iron source is (0.9~2):1; Solvent I is selected from at least one of methanol, ethanol, and acetone; The temperature of drying I is 80~110 ℃, and the drying time is 2~5 h; The calcination temperature I is 600~1200℃, and the calcination time I is 4~8 h.

5. The preparation method according to claim 2, characterized in that, In step (2), the mass ratio of ZnFeO4 to ZrO2 in ZnFeO4-ZrO2 is 100:(3~20). Solvent II is selected from ethanol and / or water; The temperature of drying II is 80~110℃, and the drying time of drying II is 2~5 h; The calcination temperature II is 500~600 ℃, and the calcination time II is 4~8 h.

6. The preparation method according to claim 2, characterized in that, In step (3), the solid-liquid ratio of the ZnFeO4-ZrO2 to the H2SO4 solution is 1:20~30 g / ml; The concentration of the H2SO4 solution is 0.1~2 M; The soaking time is 4 to 24 hours.

7. The preparation method according to claim 2, characterized in that, In step (3), the temperature of drying III is 80~110℃, and the drying time of drying III is 2~5 h; The calcination temperature of the third stage is 400~600℃, and the calcination time of the third stage is 3~6h.

8. The preparation method according to claim 1, characterized in that, The reaction temperature is 80~200℃.

9. The preparation method according to claim 1, characterized in that, In the reaction, the N2 flow rate is 0-30 ml / min; The mass hourly space velocity (MSV) of the reaction is 0.2–2 h⁻¹. -1 .

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