Preparation method of cyclic ether

Abstract

The invention discloses a preparation method of cyclic ether. The preparation method comprises the following steps: carrying out contact reaction on ethylene glycol and a catalyst to obtain 1, 4-dioxane; the catalyst is a phosphorus-modified hierarchical pore H-type molecular sieve. The catalyst provided by the invention is applied to a reaction for preparing 1, 4-dioxane through an ethylene glycol dehydration reaction, so that the conversion rate of ethylene glycol and the selectivity of the generated 1, 4-dioxane are improved.

Description

Technical Field

[0001] The present application relates to a method for preparing a cyclic ether, and belongs to the field of chemical industry. Background Art

[0002] In recent years, with the continuous breakthrough and improvement of coal-to-ethylene glycol industrial technology, my country's ethylene glycol production has increased rapidly. However, the product quality of coal-to-ethylene glycol still needs to be improved, and it is currently difficult to meet the requirements of the polyester industry. Therefore, the development of downstream products of ethylene glycol has very considerable economic benefits and strategic significance. Among them, the process of preparing 1,4-dioxane from ethylene glycol has received widespread attention due to its greater competitiveness.

[0003] 1,4-Dioxane is an important chemical raw material, widely used in paint, dye, plasticizer, wetting agent, medicine and petrochemical industries. The traditional industrial technology for preparing 1,4-dioxane from ethylene glycol mostly uses concentrated sulfuric acid or phosphoric acid as a catalyst to carry out ethylene glycol dehydration reaction. This technology not only has many by-products and cumbersome post-processing, but also causes serious corrosion to equipment and produces a large amount of waste acid and wastewater. Therefore, it is of great significance to develop catalysts with good activity, high selectivity, good stability, and low cost and environmental protection.

[0004] Solid acid catalysts have become the focus of researchers due to their many advantages such as high activity, high selectivity and easy separation. There are still few solid acid catalysts reported in the literature for catalyzing the dehydration reaction of ethylene glycol. With the advancement of science and technology and the improvement of people's environmental awareness, in chemical production, a solid acid catalyst with advantages such as recyclability and reuse is gradually replacing traditional proton acid catalysts. Summary of the invention

[0005] The present invention is of great significance in applying the modified multi-level pore molecular sieve catalyst to the preparation process of 1,4-dioxane. The catalyst has good activity, high ethylene glycol conversion rate and 1,4-dioxane selectivity, and good stability.

[0006] According to one aspect of the present application, a method for preparing a cyclic ether is provided, the method comprising: contacting ethylene glycol with a catalyst to react to obtain 1,4-dioxane;

[0007] The catalyst is a phosphorus-modified multi-level pore H-type molecular sieve.

[0008] Ethylene glycol is contacted with a catalyst to react and obtain 1,4-dioxane.

[0009] Optionally, the method for preparing the modified multi-level pore molecular sieve comprises the following steps:

[0010] (1) treating the molecular sieve with alkali and exchanging hydrogen ions to obtain a multi-level pore molecular sieve material;

[0011] (2) Immersing the multi-level pore molecular sieve material in a phosphorus source solution, stirring I, drying I, and calcining I to obtain the phosphorus-modified multi-level pore H-type molecular sieve.

[0012] Optionally, in step (1), the alkali treatment comprises the following steps: treating the molecular sieve with alkali solution, drying II, and calcining II.

[0013] Optionally, the solid-liquid ratio of the molecular sieve to the alkali solution is 1:20-30 mol / L.

[0014] Optionally, the solid-liquid ratio of the molecular sieve to the alkali solution is selected from any value of 1:20 mol / L, 1:25 mol / L, 1:30 mol / L, or a range between any two of the above values;

[0015] Optionally, the alkali solution treatment is carried out at a temperature of 65 to 90° C. and for a time of 0.5 to 1.5 hours.

[0016] Optionally, the temperature of the alkali solution treatment is selected from any value of 65°C, 70°C, 75°C, 80°C, 85°C, 90°C or a range between any two of the above values.

[0017] Optionally, the time of the alkali solution treatment is selected from any value of 0.5 hours, 1 hour, 1.5 hours, or a range between any two of the above.

[0018] Optionally, the alkali solution is selected from at least one of a NaOH solution and a KOH solution.

[0019] Optionally, the alkali solution is NaOH solution.

[0020] Optionally, the concentration of the alkali solution is 0.1-0.3 mol / L.

[0021] Optionally, the concentration of the alkali solution is selected from any value among 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L or a range between any two of the above.

[0022] Optionally, the temperature of the drying II is 80 to 130° C., and the time of the drying II is 8 to 24 hours.

[0023] Optionally, the drying temperature II is selected from any value of 80°C, 90°C, 100°C, 110°C, 120°C, 130°C or a range between any two of the above values.

[0024] Optionally, the drying time II is selected from any value of 8 hours, 12 hours, 16 hours, 20 hours, 24 hours, or a range between any two of the above.

[0025] Optionally, the temperature of the calcination II is 450-650° C., and the time of the calcination II is 1-6 hours.

[0026] Optionally, the temperature of the calcination II is selected from any value of 450°C, 500°C, 550°C, 600°C, 650°C or a range between any two of the above values.

[0027] Optionally, the calcination II time is selected from any value of 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or a range between any two of the above.

[0028] Optionally, in step (1), the hydrogen ion exchange comprises the following steps: treating the alkali-treated molecular sieve material with an ammonium salt solution, drying III, and calcining III.

[0029] Optionally, the temperature of the ammonium salt solution treatment is 65 to 90° C., and the time is 4 to 8 hours.

[0030] Optionally, the temperature of the ammonium salt solution treatment is selected from any value of 65°C, 70°C, 75°C, 80°C, 85°C, 90°C or a range between any two of the above values.

[0031] Optionally, the treatment time of the ammonium salt solution is selected from any value of 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or a range between any two of the above.

[0032] Optionally, the ammonium salt solution comprises NH4NO3 solution.

[0033] Optionally, the ammonium salt solution is NH4NO3 solution.

[0034] Optionally, the concentration of the NH4NO3 solution is 0.4-1.2 mol / L.

[0035] Optionally, the concentration of the NH4NO3 solution is selected from any value among 0.4mol / L, 0.5mol / L, 0.6mol / L, 0.7mol / L, 0.8mol / L, 0.9mol / L, 1.0mol / L, 1.1mol / L, 1.2mol / L or a range between any two of the above.

[0036] Optionally, the drying step III is performed at a temperature of 80 to 130° C. and for a time of 8 to 24 hours.

[0037] Optionally, the drying temperature of III is selected from any value of 80°C, 90°C, 100°C, 110°C, 120°C, 130°C or a range between any two of the above values.

[0038] Optionally, the drying time of III is selected from any value of 8 hours, 12 hours, 16 hours, 20 hours, 24 hours, or a range between any two of the above.

[0039] Optionally, the calcination III is carried out at a temperature of 450 to 650° C. and for a time of 1 to 6 hours.

[0040] Optionally, the temperature of calcining III is selected from any value of 450°C, 500°C, 550°C, 600°C, 650°C or a range between any two of the above values.

[0041] Optionally, the calcination time of III is selected from any value of 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or any range between the two.

[0042] Optionally, in step (2), the phosphorus source solution is selected from ammonium phosphate and / or diammonium hydrogen phosphate.

[0043] Optionally, in step (2), the phosphorus source loading mass fraction in the phosphorus source solution is 4 to 12 wt %.

[0044] Optionally, the phosphorus source loading mass fraction in the phosphorus source solution is selected from any value of 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt% or a range between any two of the above.

[0045] Optionally, in step (2), the stirring temperature I is 50 to 80° C., and the stirring time I is 2 to 6 hours.

[0046] Optionally, the stirring temperature I is selected from any value of 50°C, 60°C, 70°C, 80°C or a range between any two of the above values.

[0047] Optionally, the stirring time I is selected from any value among 2 hours, 3 hours, 4 hours, 5 hours, 6 hours or a range value between any two of the above.

[0048] Optionally, the temperature of the drying I is 80 to 130° C., and the time of the drying I is 8 to 24 hours.

[0049] Optionally, the drying temperature I is selected from any value of 80°C, 90°C, 100°C, 110°C, 120°C, 130°C or a range between any two of the above values.

[0050] Optionally, the drying time I is selected from any value among 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 24 hours, or a range between any two of the above.

[0051] Optionally, the temperature of the calcination I is 450-650° C., and the time of the calcination I is 1-6 hours.

[0052] Optionally, the calcination temperature I is selected from any value of 450°C, 500°C, 550°C, 600°C, 650°C or a range between any two of the above values.

[0053] Optionally, the calcination time I is selected from any value of 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or a range between any two of the above.

[0054] Optionally, the calcination atmosphere is N2, and the gas flow rate of N2 is 10 to 30 ml / min.

[0055] Optionally, the gas flow rate of N2 is selected from any value of 10 ml / min, 20 ml / min, 30 ml / min, or a range between any two of the above values.

[0056] Optionally, the reaction temperature is 100-200°C.

[0057] Optionally, the reaction temperature is selected from any value of 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or a range between any two of the above.

[0058] Optionally, the flow rate of N2 in the reaction is 0 to 30 ml / min.

[0059] Optionally, the flow rate of N2 in the reaction is 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.

[0060] Optionally, the mass space velocity of the reaction is 0.2 to 2 h -1 .

[0061] Optionally, the mass space velocity of the reaction is 0.2h -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.

[0062] Optionally, in step (1), the molecular sieve is at least one selected from hydrogen-type MCM-22 molecular sieve, hydrogen-type ZSM-35 molecular sieve, hydrogen-type ZSM-5 molecular sieve, hydrogen-type mercerized molecular sieve, hydrogen-type Y molecular sieve, and hydrogen-type Beta molecular sieve.

[0063] Optionally, the Si / Al ratio of the molecular sieve is 10-100.

[0064] Optionally, the Si / Al ratio of the molecular sieve is selected from any value of 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 or a range between any two of the above.

[0065] The beneficial effects of this application include:

[0066] 1) The catalyst provided in the present application can be used in the dehydration reaction of ethylene glycol to prepare 1,4-dioxane, and can improve the conversion rate of ethylene glycol and the selectivity of the generated 1,4-dioxane.

[0067] 2) The preparation method of the catalyst provided in this application is stable, controllable and reproducible.

[0068] 3) The method for preparing 1,4-dioxane by dehydrating ethylene glycol provided in the present application uses the catalyst provided in the present application, has a fast reaction speed and a high yield, and can be applied to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 Catalyst 1 in Example 1 of the present application # Reaction results catalyst 1 # Gas chromatography-mass spectrometry diagram. DETAILED DESCRIPTION

[0070] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0071] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0072] The gas chromatograph is a 7890B gas chromatograph from Agilent.

[0073] In the examples of this application, the conversion rate and selectivity are calculated as follows:

[0074] The conversion rate and selectivity calculation formula in the examples of the present application are as follows (with ethylene glycol conversion rate as the evaluation index):

[0075] Ethylene glycol conversion rate = (initial carbon number of ethylene glycol - carbon number of ethylene glycol in the product) * 100 / initial mole number of ethylene glycol

[0076] 1,4-dioxane selectivity = carbon number of 1,4-dioxane*100 / ∑(carbon number of 1,4-dioxane+carbon number of other products).

[0077] Example 1 Preparation of Catalyst

[0078] The solution temperature was maintained at 65°C, and the hydrogen-type ZSM-5 molecular sieve (Si / Al ratio was 30) was treated with a 0.1 mol / L NaOH solution for 0.5 hours, washed to neutrality, dried at 80°C for 24 hours, and calcined at 550°C for 1 hour to obtain a Na-type multi-level porous molecular sieve material; the solution temperature was maintained at 90°C, and the Na-type multi-level porous molecular sieve material was treated with a 0.6 mol / L NH4NO3 solution for 6 hours, washed, dried at 130°C for 8 hours, and calcined at 550°C for 1 hour to obtain a hydrogen-type multi-level porous molecular sieve material; the multi-level porous molecular sieve material was immersed in a diammonium hydrogen phosphate solution with a loading mass fraction of 4 wt%, stirred at 80°C for 4 hours, dried at 120°C for 12 hours, and calcined at 550°C for 1 hour in a N2 atmosphere with a gas flow rate of 20 ml / min to obtain a modified multi-level porous molecular sieve catalytic material, which was recorded as catalyst 1 # .

[0079] According to the following steps, the types, amounts and reaction parameters of each raw material are adjusted to obtain a series of catalysts numbered 1 to 28, which are recorded as catalyst 1. # ~Catalyst 28 # , as shown in the following Tables 1 to 3:

[0080] Table 1

[0081]

[0082]

[0083] Table 2

[0084]

[0085]

[0086] The columns in Tables 1 and 2 above are described as follows:

[0087] Molecular sieve types: hydrogenated MCM-22 molecular sieve (sieve 1), hydrogenated ZSM-35 molecular sieve (sieve 2), hydrogenated ZSM-5 molecular sieve (sieve 3), hydrogenated mercerized molecular sieve (sieve 4), hydrogenated Y molecular sieve (sieve 5) and hydrogenated Beta molecular sieve (sieve 6).

[0088] Alkali Type: NaOH (Alkali 1), KOH (Alkali 2).

[0089] Table 3

[0090]

[0091]

[0092] The columns in Table 3 above are explained as follows:

[0093] Phosphorus source: ammonium phosphate (P1), diammonium hydrogen phosphate (P2).

[0094] Comparative Example 1

[0095] The solution temperature was maintained at 65°C, and the hydrogen-type ZSM-5 molecular sieve (Si / Al ratio was 30) was treated with a 0.1 mol / L NaOH solution for 0.5 hours, washed to neutrality, dried at 80°C for 24 hours, and calcined at 550°C for 1 hour to obtain a Na-type multi-level porous molecular sieve material; the solution temperature was maintained at 90°C, and the Na-type multi-level porous molecular sieve material was treated with a 0.6 mol / L NH4NO3 solution for 6 hours, washed, and dried at 130°C for 8 hours, and calcined at 550°C for 1 hour to obtain a hydrogen-type multi-level porous molecular sieve material, which was recorded as catalyst 29. # .

[0096] Example 2

[0097] The catalyst 1 prepared in Example 1 was used # ~Catalyst 29 # The reaction of preparing 1,4-dioxane by dehydration of ethylene glycol was carried out, and the reaction parameters were changed. After the reaction was stable (reaction time 6 hours), the reaction raw materials and products were analyzed by gas chromatography online. The reaction results are shown in Table 4. Gas chromatography characterization: The composition of the ethylene glycol dehydration reaction product was analyzed using an Agilent 7890B gas chromatograph (FID detector, FFAP capillary column).

[0098] Table 4

[0099]

[0100]

[0101] 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 a cyclic ether, characterized in that: The preparation method comprises: contacting ethylene glycol with a catalyst to react to obtain 1,4-dioxane; The catalyst is a phosphorus-modified multi-level pore H-type molecular sieve.

2. The preparation method according to claim 1, characterized in that: The preparation method of the modified multi-level pore molecular sieve comprises the following steps: (1) treating the molecular sieve with alkali and exchanging hydrogen ions to obtain a multi-level pore molecular sieve material; (2) Immersing the multi-level pore molecular sieve material in a phosphorus source solution, stirring, drying, and calcining to obtain the phosphorus-modified multi-level pore H-type molecular sieve.

3. The preparation method according to claim 2, characterized in that: In the step (2), the phosphorus source in the phosphorus source solution is selected from ammonium phosphate and / or diammonium hydrogen phosphate.

4. The preparation method according to claim 2, characterized in that: In the step (2), the phosphorus source loading mass fraction in the phosphorus source solution is 4 to 12 wt %.

5. The preparation method according to claim 2, characterized in that: In the step (2), the stirring temperature is 50 to 80° C., and the stirring time is 2 to 6 hours.

6. The preparation method according to claim 2, characterized in that: The drying temperature is 80 to 130° C., and the drying time is 8 to 24 hours.

7. The preparation method according to claim 2, characterized in that: The calcination temperature is 450-650°C and the calcination time is 1-6 hours; Preferably, the calcination atmosphere is N2, and the gas flow rate of N2 is 10 to 30 ml / min.

8. The preparation method according to claim 1, characterized in that: The reaction temperature is 100-200°C; The flow rate of N2 in the reaction is 0-30 ml / min; The mass space velocity of the reaction is 0.2 to 2 h -1 .

9. The preparation method according to claim 2, characterized in that: In the step (1), the molecular sieve is at least one selected from hydrogen-type MCM-22 molecular sieve, hydrogen-type ZSM-35 molecular sieve, hydrogen-type ZSM-5 molecular sieve, hydrogen-type mercerized molecular sieve, hydrogen-type Y molecular sieve, and hydrogen-type Beta molecular sieve.

10. The preparation method according to claim 2, characterized in that: The Si / Al ratio of the molecular sieve is 10-100.

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