A process for the preparation of 1,4-dioxane

Abstract

The application discloses a preparation method of 1,4-dioxane, which comprises the following steps: reacting ethylene glycol with a catalyst to obtain 1,4-dioxane; and the catalyst is HClO4 / pure silicon molecular sieve. The catalyst provided by the application is applied to the dehydration reaction of ethylene glycol to prepare 1,4-dioxane, so as to improve the conversion rate of ethylene glycol and the selectivity of the generated 1,4-dioxane.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of 1,4-dioxane and belongs to the technical field of chemical industry. BACKGROUND

[0002] 1,4-dioxane is an excellent aprotic solvent, which is widely used in various special chemical manufacturing, medical supplies, petrochemical, paint manufacturing and other industries due to its high flowability and good solubility. At present, 1,4-dioxane is mainly used as a solvent for nitrocellulose, celluloid, cellulose resin, vegetable oil, mineral oil and oil-soluble dye; 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, developing downstream products of ethylene glycol has very considerable economic benefits and strategic significance. Among them, the process for preparing 1,4-dioxane from ethylene glycol has attracted widespread attention due to its great competitiveness. Therefore, it is of great significance to develop a catalyst 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 high activity, high selectivity and easy separation and other advantages. There are still few reports on solid acid catalysts for catalyzing the dehydration reaction of ethylene glycol. With the progress of science and technology and the improvement of people's environmental protection consciousness, in chemical production, a solid acid catalyst with the advantages of recyclability and reusability is gradually replacing traditional proton acid catalysts. SUMMARY

[0005] The application has great significance in applying a solid acid catalyst to the preparation process of 1,4-dioxane, and 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 application, a preparation method of 1,4-dioxane is provided, which comprises: reacting ethylene glycol with a catalyst to obtain 1,4-dioxane.

[0007] The catalyst is HClO4 / pure silica molecular sieve obtained by impregnating pure silica molecular sieve with a perchloric acid solution.

[0008] Optionally, the preparation method of the HClO4 / pure silica molecular sieve comprises:

[0009] The mixture containing pure silica molecular sieve, diethyl ether and a perchloric acid solution is stirred and dried to obtain the HClO4 / pure silica molecular sieve.

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

[0011] Optionally, the solid-liquid ratio of the pure silica molecular sieve, diethyl ether, perchloric acid solution is independently selected from any value or a range value between any two of 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.

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

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

[0014] Optionally, the pure silica molecular sieve is selected from at least one of pure silica SBA-15, pure silica Silicalite-1, pure silica MCM-41.

[0015] Optionally, the stirring time is 1-4 h.

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

[0017] Optionally, the drying temperature is 80-120℃, and the drying time is 1-10 h.

[0018] Optionally, the drying temperature is independently selected from any value or a range value between any two of 80℃, 90℃, 100℃, 110℃, 120℃.

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

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

[0021] Optionally, the reaction temperature is independently selected from any value or a range value between any two of 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃.

[0022] Optionally, the N2 flow rate in the reaction is 0-30 ml / min.

[0023] Optionally, the N2 flow rate in the reaction is independently selected from any value or a range between any two of 0 ml / min, 5 ml / min, 10 ml / min, 15 ml / min, 20 ml / min, 25 ml / min, 30 ml / min.

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

[0025] Optionally, the mass space velocity of the reaction is independently selected from any value or a range between any two of 0.2 h -1 , 0.4 h -1 , 0.6 h -1 , 0.8 h -1 , 1.0 h -1 , 1.2 h -1 , 1.4 h -1 , 1.6 h -1 , 1.8 h -1 , 2.0 h -1 .

[0026] The beneficial effects that can be produced by the present application include:

[0027] 1) The solid acid catalyst HClO4 / pure silicon molecular sieve provided by the present application can be applied in the reaction of preparing 1,4-dioxane from ethylene glycol dehydration, and the conversion rate of ethylene glycol and the selectivity of the generated 1,4-dioxane are improved.

[0028] 2) The preparation method of the solid acid catalyst HClO4 / pure silicon molecular sieve provided by the present application is stable, controllable and reproducible.

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

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

[0031] The present application will be described in detail below in combination with examples, but the present application is not limited to these examples.

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

[0033] Among them, the gas chromatograph is a 7890B type gas chromatograph of Agilent Company.

[0034] The conversion rate and selectivity in the embodiments of the present application are calculated as follows:

[0035] The conversion rate and selectivity in the embodiments of the present application are calculated 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 moles 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] The catalyst 1 # was subjected to specific surface area characterization using a QuadraSorb SI4 type physical adsorption instrument from Quantachrome.

[0040] Example 1 Preparation of catalyst

[0041] Pure silica SBA-15 was added to anhydrous ether, and perchloric acid solution was poured into it (solid-liquid ratio of 1:10:0.05 g / ml), the mass fraction of the perchloric acid solution was 70 wt.%, after stirring for 2 h, anhydrous ether was removed by evaporation, and the solid acid catalyst 1 # , i.e. HClO4 / pure silica molecular sieve (HClO4 / pure silica SBA-15) was obtained by drying at 100°C for 2 h. As shown in Figure 1 , the micropore specific surface area of the catalyst 1 # was 717.95 m 2 / g, and the mesopore specific surface area was 86.54 m 2 / g.

[0042] Example 2

[0043] Pure silica SBA-15 was added to anhydrous ether, and perchloric acid solution was poured into it (solid-liquid ratio of 1:20:0.05 g / ml), the mass fraction of the perchloric acid solution was 60 wt.%, after stirring for 1 h, anhydrous ether was removed by evaporation, and the solid acid catalyst 2 # , i.e. HClO4 / pure silica molecular sieve (HClO4 / pure silica SBA-15) was obtained by drying at 120°C for 1 h.

[0044] Example 3

[0045] Pure silica Silicalite-1 was added to anhydrous ether, and perchloric acid solution was poured into it (solid-liquid ratio of 1:25:0.05 g / ml), the mass fraction of the perchloric acid solution was 80 wt.%, after stirring for 4 h, anhydrous ether was removed by evaporation, and the solid acid catalyst 3 #i.e. HClO4 / pure silica Silicalite-1.

[0046] Example 4

[0047] Pure silica MCM-41 was added to anhydrous ether, poured into a solution of perchloric acid (solid-liquid ratio of 1 : 15: 0.1 g / ml), the mass fraction of the perchloric acid solution was 80 wt.%, after stirring for 3 h, the anhydrous ether was removed by evaporation, and a solid acid catalyst 4 was obtained by drying at 90 °C for 5 h # i.e. HClO4 / pure silica MCM-41.

[0048] Example 5

[0049] Pure silica Silicalite-1 was added to anhydrous ether, poured into a solution of perchloric acid (solid-liquid ratio of 1 : 30: 0.1 g / ml), the mass fraction of the perchloric acid solution was 70 wt.%, after stirring for 4 h, the anhydrous ether was removed by evaporation, and a solid acid catalyst 5 was obtained by drying at 80 °C for 6 h # i.e. HClO4 / pure silica Silicalite-1.

[0050] Example 6

[0051] Pure silica SBA-15 was added to anhydrous ether, poured into a solution of perchloric acid (solid-liquid ratio of 1 : 15: 0.15 g / ml), the mass fraction of the perchloric acid solution was 60 wt.%, after stirring for 1 h, the anhydrous ether was removed by evaporation, and a solid acid catalyst 6 was obtained by drying at 100 °C for 3 h # i.e. HClO4 / pure silica SBA-15.

[0052] Example 7

[0053] Pure silica Silicalite-1 was added to anhydrous ether, poured into a solution of perchloric acid (solid-liquid ratio of 1 : 20: 0.15 g / ml), the mass fraction of the perchloric acid solution was 70 wt.%, after stirring for 2 h, the anhydrous ether was removed by evaporation, and a solid acid catalyst 7 was obtained by drying at 110 °C for 7 h # i.e. HClO4 / pure silica Silicalite-1.

[0054] Example 8

[0055] Pure silica MCM-41 was added to anhydrous ether, poured into a solution of perchloric acid (solid-liquid ratio of 1 : 30: 0.15 g / ml), the mass fraction of the perchloric acid solution was 60 wt.%, after stirring for 3 h, the anhydrous ether was removed by evaporation, and a solid acid catalyst 8 was obtained by drying at 90 °C for 9 h #i.e. HClO4 / pure silica molecular sieve (HClO4 / pure silica MCM-41).

[0056] Example 9

[0057] Using the catalyst 1 prepared in Examples 1-8 # ~8 # The ethylene glycol dehydration reaction for preparing 1,4-dioxane was carried out, and each reaction parameter was changed. After the reaction was stable (for 6 hours), the reaction raw materials and products were analyzed by using gas phase online chromatography. The reaction results are shown in Table 1.

[0058] Gas chromatography characterization:

[0059] Agilent 7890B gas chromatography (FID detector, FFAP capillary column) was used to analyze the composition of the ethylene glycol dehydration reaction product.

[0060] Table 1

[0061]

[0062] As can be seen from Table 1, the selectivity of directly using pure silica molecular sieve to prepare 1,4-dioxane is lower than that of using HClO4 / pure silica molecular sieve to prepare 1,4-dioxane.

[0063] The above is only a few embodiments of the present application, and does not limit the present application in any form. Although the above preferred embodiments are disclosed, they are not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, which are equivalent to equivalent embodiments, and all belong to the scope of the technical solution.

Claims

1. A method for preparing 1,4-dioxane, characterized in that, The preparation method includes: reacting ethylene glycol with a catalyst to obtain 1,4-dioxane; The catalyst is HClO4 / pure silicon molecular sieve obtained by impregnating pure silicon molecular sieve with perchloric acid solution.

2. The preparation method according to claim 1, characterized in that, The preparation method of the HClO4 / pure silica molecular sieve includes: A mixture containing pure silicon molecular sieve, diethyl ether, and perchloric acid solution is stirred and dried to obtain the HClO4 / pure silicon molecular sieve.

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

4. The preparation method according to claim 2, characterized in that, The perchloric acid solution has a mass fraction of 60–80 wt.%.

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

7. The preparation method according to claim 2, 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, characterized in that, The reaction temperature is 100–200°C.

9. The preparation method according to claim 1, characterized in that, The N2 flow rate in the reaction is 0–30 ml / min.

10. The preparation method according to claim 1, characterized in that, The mass hourly space velocity (MSV) of the reaction is 0.2–2 h⁻¹. -1 .

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