Preparation method of 1, 4-dioxane

Abstract

The invention discloses a 1, 4-dioxane preparation method, which comprises: carrying out a contact reaction on ethylene glycol and a catalyst to obtain 1, 4-dioxane, the catalyst is an HClO4 / pure silicon 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 1,4-dioxane, and belongs to the technical field of chemical industry. Background Art

[0002] 1,4-Dioxane is an excellent aprotic solvent. Due to its high fluidity and good solubility, it is widely used in various specialty chemicals, pharmaceuticals, petrochemicals, paint and other industries. Currently, it is mainly used as a solvent for nitrocellulose, celluloid, cellulose resin, vegetable oil, mineral oil and oil-soluble dyes; in the production of polyurethane synthetic leather and amino acid synthetic leather, 1,4-dioxane can replace tetrahydrofuran and dimethylformamide as a reaction solvent.

[0003] In recent years, the development of downstream products of ethylene glycol has considerable economic benefits and strategic significance. Among them, the process of preparing 1,4-dioxane from ethylene glycol has received extensive attention due to its greater competitiveness. Therefore, it is of great significance to develop catalysts with good activity, high selectivity, good stability, 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 application of the solid acid catalyst in the preparation process of 1,4-dioxane has great significance. 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 1,4-dioxane is provided, the method comprising: contacting ethylene glycol with a catalyst to react to obtain 1,4-dioxane;

[0007] The catalyst is HClO obtained by impregnating pure silicon molecular sieve with perchloric acid solution 4 / Pure silicon molecular sieve.

[0008] Optionally, the HClO 4 / The preparation method of pure silicon molecular sieve comprises:

[0009] A mixture containing pure silicon molecular sieve, ether and perchloric acid solution is stirred and dried to obtain the HClO 4 / Pure silicon molecular sieve.

[0010] Optionally, the solid-liquid ratio of the pure silicon molecular sieve, ether and perchloric acid is 1:10-30:0.05-0.15 g / ml.

[0011] Optionally, the solid-to-liquid ratio of the pure silicon molecular sieve, ether and perchloric acid solution is independently selected from any value among 1:10:0.05, 1:15:0.05, 1:20:0.05, 1:25:0.05, 1:30:0.05, 1:10:0.1, 1:15:0.1, 1:20:0.1, 1:25:0.1, 1:30:0.1, 1:10:0.15, 1:15:0.15, 1:20:0.15, 1:25:0.15, 1:30:0.15 or any range value between any two of them.

[0012] Optionally, the mass fraction of the perchloric acid solution is 60-80wt.%.

[0013] Optionally, the mass fraction of the perchloric acid solution is independently selected from any value of 60wt.%, 70wt.%, 80wt.%, or any range value therebetween.

[0014] Optionally, the pure silicon molecules are selected from at least one of pure silicon SBA-15, pure silicon Silicalite-1, and pure silicon MCM-41.

[0015] Optionally, the stirring time is 1 to 4 hours.

[0016] Optionally, the stirring time is independently selected from any value among 1 h, 2 h, 3 h, 4 h, or any range between the two.

[0017] Optionally, the drying temperature is 80-120° C., and the drying time is 1-10 hours.

[0018] Optionally, the drying temperature is independently selected from any value among 80°C, 90°C, 100°C, 110°C, 120°C, or any range therebetween.

[0019] Optionally, the drying time is independently selected from any value among 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, or any range between two of them.

[0020] Optionally, the reaction temperature is 100-200°C.

[0021] Optionally, the reaction temperature is independently 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 any range therebetween.

[0022] Optionally, N in the reaction 2 The flow rate is 0~30ml / min.

[0023] Optionally, N in the reaction 2 The flow rate is independently selected from any value among 0 ml / min, 5 ml / min, 10 ml / min, 15 ml / min, 20 ml / min, 25 ml / min, 30 ml / min or any range therebetween.

[0024] Optionally, the mass space velocity of the reaction is 0.2 to 2 h -1 .

[0025] Optionally, the mass space velocity of the reaction is independently selected from 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 any range between them.

[0026] The beneficial effects of this application include:

[0027] 1) The solid acid catalyst HClO provided in the present application 4 / Pure silicon molecular sieve can be used in the dehydration reaction of ethylene glycol to prepare 1,4-dioxane, and improve the conversion rate of ethylene glycol and the selectivity of the generated 1,4-dioxane.

[0028] 2) The solid acid catalyst HClO provided in this application 4 / The preparation method of pure silicon molecular sieve is stable, controllable and reproducible.

[0029] 3) The method for preparing 1,4-dioxane by dehydrating ethylene glycol provided in the present application uses a solid acid catalyst, has a fast reaction speed, a high yield, and can be applied to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the BET diagram of the solid acid catalyst prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0031] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0032] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0033] The gas chromatograph is a 7890B gas chromatograph from Agilent.

[0034] In the examples of this application, the conversion rate and selectivity are calculated as follows:

[0035] 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):

[0036] 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

[0037] 1,4-dioxane selectivity = carbon number of 1,4-dioxane*100 / ∑(carbon number of 1,4-dioxane+carbon number of other products).

[0038] BET Characterization:

[0039] Catalyst 1 was subjected to physical adsorption using a Quantachrome QuadraSorb SI4 instrument. # Characterize the specific surface area.

[0040] Example 1 Preparation of Catalyst

[0041] Pure silicon SBA-15 was added to anhydrous ether, and a perchloric acid solution (solid-liquid ratio of 1:10:0.05 g / ml) was poured in, and the mass fraction of the perchloric acid solution was 70 wt.%. After stirring for 2 hours, the anhydrous ether was evaporated and dried at 100°C for 2 hours to obtain solid acid catalyst 1 # , namely HClO 4 / Pure silicon molecular sieve (HClO 4 / pure silicon SBA-15). Figure 1 As shown, catalyst 1 # The micropore specific surface area is 717.95m 2 / g, and the mesopore specific surface area is 86.54m 2 / g.

[0042] Example 2

[0043] Pure silicon SBA-15 was added to anhydrous ether, and a perchloric acid solution (solid-liquid ratio of 1:20:0.05 g / ml) was poured in. The mass fraction of the perchloric acid solution was 60 wt.%. After stirring for 1 hour, the anhydrous ether was evaporated and dried at 120°C for 1 hour to obtain solid acid catalyst 2 # , namely HClO 4 / Pure silicon molecular sieve (HClO 4 / pure silicon SBA-15).

[0044] Example 3

[0045] Pure silicon Silicalite-1 was added to anhydrous ether, and a perchloric acid solution (solid-liquid ratio of 1:25:0.05 g / ml) was poured in, and the mass fraction of the perchloric acid solution was 80 wt.%. After stirring for 4 hours, the anhydrous ether was evaporated and dried at 110°C for 4 hours to obtain solid acid catalyst 3 # , namely HClO 4 / Pure silicon molecular sieve (HClO 4 / Pure Silicon Silicalite-1).

[0046] Example 4

[0047] Pure silicon MCM-41 was added to anhydrous ether, and a perchloric acid solution (solid-liquid ratio of 1:15:0.1 g / ml) was poured in. The mass fraction of the perchloric acid solution was 80 wt.%. After stirring for 3 h, the anhydrous ether was evaporated and dried at 90 °C for 5 h to obtain solid acid catalyst 4. # , namely HClO 4 / Pure silicon molecular sieve (HClO 4 / pure silicon MCM-41).

[0048] Example 5

[0049] Pure Silicalite-1 was added to anhydrous ether, and a perchloric acid solution (solid-liquid ratio of 1:30:0.1 g / ml) was added. The mass fraction of the perchloric acid solution was 70 wt.%. After stirring for 4 hours, the anhydrous ether was evaporated and dried at 80°C for 6 hours to obtain a solid acid catalyst 5. # , namely HClO 4 / Pure silicon molecular sieve (HClO 4 / Pure Silicon Silicalite-1).

[0050] Example 6

[0051] Pure silicon SBA-15 was added to anhydrous ether, and a perchloric acid solution (solid-liquid ratio of 1:15:0.15 g / ml) was poured in. The mass fraction of the perchloric acid solution was 60 wt.%. After stirring for 1 hour, the anhydrous ether was evaporated and dried at 100°C for 3 hours to obtain solid acid catalyst 6. # , namely HClO 4 / Pure silicon molecular sieve (HClO 4 / pure silicon SBA-15).

[0052] Example 7

[0053] Pure silicon Silicalite-1 was added to anhydrous ether, and a perchloric acid solution (solid-liquid ratio of 1:20:0.15 g / ml) was poured in. The mass fraction of the perchloric acid solution was 70 wt.%. After stirring for 2 h, the anhydrous ether was evaporated and dried at 110 ° C for 7 h to obtain solid acid catalyst 7. # , namely HClO 4 / Pure silicon molecular sieve (HClO 4 / Pure Silicon Silicalite-1).

[0054] Example 8

[0055] Pure silicon MCM-41 was added to anhydrous ether, and a perchloric acid solution (solid-liquid ratio of 1:30:0.15 g / ml) was poured in. The mass fraction of the perchloric acid solution was 60 wt.%. After stirring for 3 h, the anhydrous ether was evaporated and dried at 90 °C for 9 h to obtain a solid acid catalyst 8. # , namely HClO 4 / Pure silicon molecular sieve (HClO 4 / pure silicon MCM-41).

[0056] Example 9

[0057] Catalyst 1 prepared in Examples 1 to 8 was used # ~8 # 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 1.

[0058] Gas chromatography characterization:

[0059] The composition of the ethylene glycol dehydration reaction products was analyzed using an Agilent 7890B gas chromatograph (FID detector, FFAP capillary column).

[0060] Table 1

[0061]

[0062] As can be seen from Table 1, the selectivity of preparing 1,4-dioxane directly using pure silicon molecular sieve is lower than that of preparing 1,4-dioxane using HClO 4 / Selectivity of pure silicon molecular sieves for the preparation of 1,4-dioxane.

[0063] 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 1,4-dioxane, It is characterized in that The preparation method comprises: contacting ethylene glycol with a catalyst to react to obtain 1,4-dioxane; The catalyst is HClO obtained by impregnating pure silicon molecular sieve with perchloric acid solution 4 / Pure silicon molecular sieve.

2. The preparation method according to claim 1, It is characterized in that The HClO 4 / The preparation method of pure silicon molecular sieve comprises: A mixture containing pure silicon molecular sieve, ether and perchloric acid solution is stirred and dried to obtain the HClO 4 / Pure silicon molecular sieve.

3. The preparation method according to claim 2, It is characterized in that The solid-liquid ratio of the pure silicon molecular sieve, ether and perchloric acid solution is 1:10-30:0.05-0.15 g / ml.

4. The preparation method according to claim 2, It is characterized in that The mass fraction of the perchloric acid solution is 60-80wt.%.

5. The preparation method according to claim 2, It is characterized in that The pure silicon molecules are selected from at least one of pure silicon SBA-15, pure silicon Silicalite-1 and pure silicon MCM-41.

6. The preparation method according to claim 2, It is characterized in that The stirring time is 1 to 4 hours.

7. The preparation method according to claim 2, It is characterized in that The drying temperature is 80-120° C., and the drying time is 1-10 hours.

8. The preparation method according to claim 1, It is characterized in that The reaction temperature is 100-200°C.

9. The preparation method according to claim 1, It is characterized in that The N in the reaction 2 The flow rate is 0~30ml / min.

10. The preparation method according to claim 1, It is characterized in that The mass space velocity of the reaction is 0.2 to 2 h -1 .

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