Application of Ionic Liquid-Derived Solid Base Catalyst in the Synthesis of Lauryl Alcohol Ester Containing High Primary Ester

Abstract

The present invention relates to the technical field of catalysts, and particularly to the application of an ionic liquid-derived solid base catalyst in the synthesis of dodecyl alcohol esters containing high primary esters. The synthesized 4-butyl-1-triethoxysilylpropyltriazole chloride ionic liquid is loaded on an MCM-41 catalyst to obtain a basic catalyst. Using isobutyraldehyde as a raw material, 2,2,4-trimethyl-1,3-pentanediol and isobutyric acid are obtained through aldol condensation and Cannizzaro reaction under the condition of the basic catalyst, and then the two are subjected to an esterification reaction to obtain the dodecyl alcohol ester product containing high primary esters. The advantages of the present invention are as follows: Compared with other solvents, ionic liquids used in base-catalyzed reactions show higher selectivity for dodecyl alcohol esters containing high primary esters. The catalyst is stable and easy to prepare, with higher activity; the content of primary esters in the prepared dodecyl alcohol ester product is greater than 70%, meeting the requirements of industrial products; the catalyst is easily separated from the product, meeting the environmental protection requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and particularly to a preparation method of a solid base catalyst derived from mesoporous ionic liquid and its application in the synthesis of dodecyl alcohol ester containing high primary ester alcohol ester. Background Art

[0002] Dodecyl alcohol ester is a non - water - soluble diol ester with high boiling point and low freezing point. It is non - toxic itself and has very good compatibility with a variety of solvents. It is a generally recognized green solvent and is widely used in various aspects, such as coating film - forming aids, synthetic lubricants, synthetic plasticizers, etc. With the enhancement of environmental protection awareness, dodecyl alcohol ester with excellent performance is a volatile temporary plasticizer that can stay in the coating film during the film - forming process and play a role. After film - forming, it volatilizes completely without affecting the performance of the coating film; it does not affect the stability of the emulsion. Dodecyl alcohol ester has the above characteristics and is recognized by the coating industry as the most ideal environmentally friendly film - forming aid for latex paints in the current market.

[0003] Alcohol ester dodecyl (2,2,4 - trimethyl - 1,3 - pentanediol monoisobutyrate) is composed of two isomers, namely primary ester (3 - hydroxy - 2,2,4 - trimethyl - 1 - pentyl isobutyrate) and secondary ester (1 - hydroxy - 2,2,4 - trimethyl - 3 - pentyl isobutyrate). The reason is that during the reaction, the two hydroxyl groups of 2,2,4 - trimethyl - 1,3 - pentanediol react with isobutyric acid respectively to form esters, resulting in the generation of isomers. Moreover, the properties and uses of these two isomers are the same, so the content of alcohol ester dodecyl is the sum of the contents of these two isomers. Among them, the higher the content of primary ester alcohol ester dodecyl, the more conducive to film - forming. At present, most patents involve the preparation of secondary ester alcohol ester dodecyl, and the conversion rate of primary ester alcohol ester dodecyl is low.

[0004] "Influencing factors of the isomer ratio of dodecyl alcohol ester" shows that isobutyraldehyde, isobutyric acid and hydroxyvaleric acid will have an obvious impact on the stability of the primary / secondary ester ratio of dodecyl alcohol ester. The isomer ratio of dodecyl alcohol ester is not easily stable under the influence of temperature and acidity / alkalinity. The different ratios of primary ester and secondary ester have a certain impact on the performance of dodecyl alcohol ester. In the prior art, the content of the conventionally synthesized secondary ester is relatively high, generally the ratio of primary ester / secondary ester is 1.38 - 1.86. Some studies have shown that a high content of primary ester is beneficial to the film - forming of alcohol ester dodecyl. Therefore, the present invention wants to obtain more primary ester.

[0005] NaOH solution is used as a catalyst in patents CN1429809, CN1098712A, EPO317977A2 and US4883906 to synthesize dodecyl alcohol ester. Currently, the alkaline catalyst used has too strong alkalinity, making the reaction difficult to control, more seriously corroding equipment, resulting in high production costs and poor economic benefits, and the conversion rate of dodecyl alcohol ester cannot meet the requirements. Ionic liquids (ILs) have become the focus of extensive research due to their "green" origin, negligible vapor pressure, tunability, excellent separation ability, recyclability and simple reaction process, and have good thermal stability, high purity and strong alkalinity. For example, Chinese patent literature (application number CN201611004524.3) discloses the direct preparation of dodecyl alcohol ester in one step with isobutyraldehyde as the raw material under the action of a catalyst, and the catalyst is a dual-catalytic system composed of a supported solid base and a basic ionic liquid. This catalytic system has the advantages of easy recovery of the catalyst, good selectivity and no wastewater generation in production, but still has the problems of difficult separation and low conversion rate of dodecyl alcohol ester with high content of primary ester.

[0006] The solid base catalyst loaded with basic ionic liquid of the present invention weakens the action of this H bond, which is beneficial to the esterification of the hydroxyl group of 2,2,4-trimethyl-1,3-pentanediol with isobutyric acid, and the ionic liquid has strong alkalinity, so the content of dodecyl alcohol ester with high content of primary ester will relatively increase and stably exist. Summary of the Invention

[0007] Aiming at the deficiencies and disadvantages of the existing technology, the present invention provides a mesoporous ionic liquid-derived solid base catalyst for catalytic synthesis of dodecyl alcohol ester with high content of primary ester and its preparation method. The catalyst has high conversion rate, simple preparation scheme, is easier to separate the product dodecyl alcohol ester and can produce dodecyl alcohol ester with high content of primary ester, and has good economic efficiency and industrial value. The present invention improves the conversion of primary ester through the active center of the mesoporous ionic liquid-derived solid base catalyst to increase the stability of primary ester in dodecyl alcohol ester, thereby increasing the content of dodecyl alcohol ester with high content of primary ester.

[0008] The technical solution adopted to achieve the purpose of the present invention is as follows:

[0009] Preparation method of mesoporous ionic liquid-derived solid base catalyst: The catalyst grafts 4-butyl-1,2,4-triazole chloride onto ordered mesoporous MCM-41, and exchanges chloride ions with hydroxyl anions to obtain a supported IL catalyst (MCM-41-pr-ILOH).

[0010] The catalyst support is ordered mesoporous MCM-41, 4-butyl-1,2,4-triazole hydroxide is grafted onto the ordered mesoporous MCM-41, and the active center is the basic ions supported by MCM-41. Mesoporous silica-based MCM-41: The particle size of MCM-41 is 100-200 mesh, preferably 150-180 mesh; the BET specific surface area is 500-1500 m 2 g -1 , preferably 500-1000 m 2 g -1 ; the pore volume is 0.8-1.8 cm 3 g -1 , preferably 0.8-1.2 cm 3 g -1 ; the average pore diameter is 2-10 nm, preferably 3-5 nm.

[0011] Furthermore, the preparation method of the ordered mesoporous MCM-41 includes the following steps:

[0012] a. Dissolve 2.5 g of CTAB (cetyltrimethylammonium bromide) in 50 g of distilled water, add ammonia solution (15.1 g), and continuously stir mechanically (500 rpm) until CTAB is completely dissolved.

[0013] b. Then add 60 g of ethanol and continue stirring for 150 minutes. Then add tetraethyl orthosilicate (4.7 g) to form a white gel. Stir the obtained gel for 2 h and age it for 2 h. Filter the obtained white material, wash it with distilled water and methanol (100 ml each), and dry it overnight in an oven at 90 °C.

[0014] c. Finally, calcine the dry powder at 550 °C for 5 h to remove the template to obtain MCM-41.

[0015] The specific preparation method steps of the mesoporous ionic liquid-derived solid base catalyst are as follows:

[0016] (1) Add 3-chloropropyltriethoxysilane to the solution of 1,2,4-triazole and acetonitrile, and then carry out nucleophilic substitution by adding 1-chlorobutane and anhydrous toluene as solvents; reflux the mixture for 18-24 h under a nitrogen atmosphere to form 4-butyl-1-triethoxysilylpropyltriazole chloride, denoted as triazole IL;

[0017] The molar ratio of 1,2,4-triazole, 3-chloropropyltriethoxysilane and 1-chlorobutane is 1:1:1-1:1:4, and the volume ratio of anhydrous toluene and acetonitrile solution is 1:1-1:5;

[0018] The structural formula of the synthesized 4-butyl-1-triethoxysilylpropyltriazole chloride is:

[0019]

[0020] (2) Dissolve the triazole IL prepared in (1) in anhydrous toluene. The concentration of 4-butyl-1-triethoxysilylpropyltriazole chloride (triazole IL) in anhydrous toluene is 1 - 4 g / L, and then add the MCM-41 support. The loading amount of triazole IL is 1 - 20 wt%. Reflux the mixture under a nitrogen atmosphere for 18 - 24 h (temperature is 80 °C);

[0021] (3) After cooling the mixture in (2) to room temperature, separate the solid product by filtration, wash it thoroughly with acetone to remove the excess triazole IL, dry it in vacuum at 40 - 70 °C for 4 - 10 h, and extract the obtained solid precipitate using a mixture of ether / dichloromethane in a Soxhlet apparatus; the volume ratio of ether to dichloromethane is 1:1 - 1:3; the solid precipitation time is 4 - 8 h;

[0022] (4) Treat the solid product in (3) with a methanol solution of tetramethylammonium hydroxide (TMAOH), stir at room temperature for 4 - 8 h to exchange chloride ions with hydroxyl anions, filter, wash with ethanol, and dry in vacuum at 40 - 70 °C for 8 - 12 h. The obtained solid catalyst is labeled as MCM-41-pr-ILOH, where pr represents propyl and ILOH represents basic ionic liquid.

[0023] The catalyst obtained by the method of the present invention is used for the catalytic synthesis of high primary ester alcohol ester dodecane. The specific steps are as follows: Using isobutyraldehyde as a raw material, 2,2,4-trimethyl-1,3-pentanediol and isobutyric acid are obtained through aldol condensation and Cannizzaro reaction under the condition of a basic catalyst, and then the two are subjected to an esterification reaction to obtain the product. A solid base catalyst is used for the esterification reaction. The reaction temperature is 60 - 95 °C, the feeding time is 2 - 3 h, and the residence time is 10 - 20 min.

[0024] Specifically:

[0025] a. Add the catalyst and isobutyraldehyde to a three-necked flask equipped with a stirrer and a reflux device, and carry out the isobutyraldehyde condensation reaction at 20 - 40 °C for 2 - 3 h. The mass ratio of the catalyst to isobutyraldehyde is 0.2:50.

[0026] b. Directly heat up the mixture in a to carry out the intramolecular Cannizzaro reaction, and carry out the esterification reaction at 60 - 90 °C for 2 - 10 h to generate the second-stage main product of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (containing high primary ester alcohol ester dodecane).

[0027] c. Collect the 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate product in a distillation column. The column temperature is 60 - 95 °C, the vacuum degree is not less than 7.9×10 -2 MPa, and the reflux ratio is 1:4.

[0028] The above reaction uses isobutyraldehyde as a raw material, adds a basic catalyst, and is synthesized through two-stage reactions. Among them, the first stage is the aldol condensation reaction of isobutyraldehyde itself, and the product is 2,2,4-trimethyl-3-hydroxypentanal (HPA). The second-stage reaction is the intermolecular Cannizzaro disproportionation reaction of HPA and isobutyraldehyde, generating 2,2,4-trimethyl-1,3-pentanediol (TMPD) and isobutyric acid. The two are esterified to form 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and the content of the primary ester exceeds 70%.

[0029] Beneficial effects

[0030] (1) The mesoporous ionic liquid-derived solid base catalyst MCM-41-pr-ILOH of the present invention has a higher yield than traditional homogeneous basic catalysts in the esterification reaction of high primary fatty alcohol ester dodecane. It is manifested that the loaded IL is fixed in the pores of MCM-41 by reacting with functional groups through surface silanols. After MCM-41 is functionalized with basic IL, it corresponds to the asymmetric stretching vibration and symmetric stretching vibration of CH2 on the propyl chain of the silylating reagent, respectively. 4-Butyl-1-triethoxysilylpropyltriazole chloride is stronger in basicity than other ionic liquids and can be better covalently anchored on MCM-41 to form a heterogeneous catalyst MCM-41-pr-ILOH, which is beneficial for the 1-hydroxy group of 2,2,4-trimethyl-1,3-pentanediol to react with isobutyric acid preferentially to generate primary fatty alcohol ester dodecane. When the loading amount of IL is increased within a certain range, the basicity of the catalyst is also correspondingly enhanced, and it can be concluded that the catalytic activity of the solid base catalyst is strongly affected by its basicity.

[0031] (2) Since MCM-41 is easily surface-modified and is commonly used as a carrier for immobilizing IL, it is a promising candidate material for catalyst carriers. The present invention realizes better loading of ionic liquids, reduces the amount of ionic liquids used, and lowers the cost by adjusting the specific surface area, pore volume, narrow pore distribution, and hydrophobicity of the mesoporous material MCM-41. The surface of the MCM-41 pore channel has easily modified silanol groups, and functional groups can be firmly bonded to the pore channel surface through a silylation reaction, increasing the surface active sites, thereby increasing the adsorption capacity and selectivity of MCM-41, which is beneficial for the catalytic synthesis of high primary ester alcohol ester dodecane.

[0032] (3) The catalyst of the present invention has no requirements for equipment, is simple to separate, and has high activity with a reaction temperature only between 60 - 95 °C, which is more conducive to chemical production. 4-butyl-1,2,4-triazole hydroxide is grafted onto MCM-41. This hybrid inorganic-organic mesoporous material can integrate the advantages of IL and heterogeneous catalysts, such as excellent catalytic efficiency and reusability. Alkaline ionic liquids have attracted attention due to their unique green characteristics, and ionic liquid catalysts have occupied the catalytic field with excellent catalytic effects. Detailed implementation manners

[0033] The present invention will be further described below in conjunction with embodiments, but not limited thereto.

[0034] Example 1

[0035] Preparation of the catalyst: Add 0.69 g of 1,2,4-triazole and 50 mL of acetonitrile solution to a three-necked flask and mix. Then add 2.41 g of 3-chloropropyltriethoxysilane. Subsequently, carry out nucleophilic substitution by adding 0.93 g of 1-chlorobutane in equimolar amount and 10 mL of anhydrous toluene as a solvent. Reflux the mixture under a nitrogen atmosphere for another 24 h to form 4-butyl-1-triethoxysilylpropyltriazole chloride. Take 0.2 g of the prepared triazole IL and dissolve it in 10 mL of anhydrous toluene, then add 2 g of MCM-41 support and reflux under a nitrogen atmosphere for 24 h. After cooling to room temperature, separate the solid product by filtration, wash it thoroughly with acetone to remove the excess IL, and dry it under vacuum at 40 °C for 4 h. Then, extract the obtained solid precipitate with a 1:1 (v / v) mixture of diethyl ether / dichloromethane in a Soxhlet apparatus for 6 h. Finally, treat the solid product with 0.21 mol / L TMAOH methanol solution and stir the resulting solution at room temperature for 4 h to exchange chloride ions with hydroxyl anions. Filter the solid catalyst thus prepared from the reaction mixture, wash it several times with ethanol, and then dry it under vacuum at 60 °C for 12 h. The obtained solid catalyst is labeled as MCM-41-pr-ILOH, where pr represents propyl and ILOH represents alkaline ionic liquid.

[0036] Add 1 g of the catalyst and 50 g of isobutyraldehyde to a 500 mL three-necked flask equipped with a stirrer and a reflux device. Carry out the aldol condensation reaction of isobutyraldehyde at 20 °C for 2 h, then directly heat and raise the temperature to carry out the intramolecular Cannizzaro reaction, and carry out the esterification reaction at 60 °C for 4 h to generate a product mainly containing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in the second stage. Collect 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a distillation column, with the column temperature of 70 °C, a vacuum degree of 7.9×10 -2 MPa and a reflux ratio of 1:4.

[0037] Example 2

[0038] Replace 2.41 g of 3-chloropropyltriethoxysilane in Example 1 with 1.2 g of 3-chloropropyltriethoxysilane.

[0039] Other steps are the same as in Example 1.

[0040] Example 3

[0041] Replace 0.93 g of 1-chlorobutane in Example 1 with 0.46 g of 1-chlorobutane, and other steps are the same as in Example 1.

[0042] Example 4

[0043] Replace the ether / dichloromethane mixture with a volume ratio of 1:1 in Example 1 with an ether / dichloromethane mixture with a volume ratio of 1:2, and other steps are the same as in Example 1.

[0044] Example 5

[0045] Add 1 g of catalyst and 50 g of isobutyraldehyde to a 500 mL three-necked flask equipped with a stirrer and a reflux device. Carry out the isobutyraldehyde condensation reaction at 20 °C for 2 h, then directly heat up to carry out the intramolecular Cannizzaro reaction, and carry out the esterification reaction at 60 °C for 4 h to produce a product mainly containing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in the second stage. Collect 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a distillation column, with the column temperature at 90 °C, the vacuum degree at 7.9×10 -2 MPa, and the reflux ratio at 1:4. Other steps are the same as in Example 1.

[0046] Example 6

[0047] Add 0.5 g of catalyst and 50 g of isobutyraldehyde to a 500 mL three-necked flask equipped with a stirrer and a reflux device. Carry out the isobutyraldehyde condensation reaction at 20 °C for 2 h, then directly heat up to carry out the intramolecular Cannizzaro reaction, and carry out the esterification reaction at 60 °C for 4 h to produce a product mainly containing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in the second stage. Collect 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a distillation column, with the column temperature at 70 °C, the vacuum degree at 7.9×10 -2 MPa, and the reflux ratio at 1:4.

[0048] Others are the same as in Example 1.

[0049] Comparative Example 1

[0050] Preparation of catalyst: 0.69 g of 1,2,4-triazole and 50 mL of acetonitrile solution were added to a three-necked flask and mixed. Then 2.41 g of 3-chloropropyltriethoxysilane was added, and subsequent nucleophilic substitution was carried out by adding 0.93 g of 1-chlorobutane and 10 mL of anhydrous toluene as a solvent in an equimolar amount. The mixture was refluxed for another 24 h under a nitrogen atmosphere to form 4-butyl-1-triethoxysilylpropyltriazole chloride. It was treated with a 0.21 mol / L TMAOH methanol solution, and the resulting solution was stirred at room temperature for 4 h to exchange chloride ions with hydroxyl anions to obtain the basic ionic liquid ILOH.

[0051] Other steps are the same as those in Example 1.

[0052] Comparative Example 2

[0053] Using pure MCM-41 as the catalyst, other steps are the same as those in Example 1.

[0054] Comparative Example 3

[0055] 1 g of ordinary solid base catalyst sodium hydroxide was taken, and after carrying out the isobutyraldehyde condensation reaction at 20 °C for 2 h, it was directly heated and the intramolecular Cannizzaro reaction was carried out. The esterification reaction was carried out at 60 °C for 4 h to generate a product mainly containing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in the second stage. 2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate was collected in a distillation column, with the column temperature of 70 °C, the vacuum degree of 7.9×10 -2 MPa, and the reflux ratio of 1:4. Other steps are the same as those in Example 1.

[0056] Comparative Example 4

[0057] Preparation of the catalyst: 0.35 g of 1,2,4-triazole and 50 mL of acetonitrile solution were added to a three-necked flask and mixed, and then 2.41 g of 3-chloropropyltriethoxysilane was added. Subsequently, nucleophilic substitution was carried out by adding 0.93 g of 1-chlorobutane in an equimolar amount and 10 mL of anhydrous toluene as a solvent. The mixture was refluxed for another 24 h under a nitrogen atmosphere to form 4-butyl-1-triethoxysilylpropyltriazole chloride. The prepared triazole IL was dissolved in anhydrous toluene, and then the MCM-41 support was added, and the mixture was refluxed for 24 h under a nitrogen atmosphere. After cooling to room temperature, the solid product was separated by filtration, thoroughly washed with acetone to remove the excess IL, and vacuum dried at 40 °C for 4 h. Then, the obtained solid precipitate was extracted in a Soxhlet apparatus with a 1:1 (v / v) mixture of diethyl ether / dichloromethane for 6 h. Finally, the solid product was treated with a 0.21 mol / L methanol solution of TMAOH, and the resulting solution was stirred at room temperature for 4 h to exchange chloride ions with hydroxyl anions. The solid catalyst thus prepared was filtered from the reaction mixture, washed several times with ethanol, and then vacuum dried at 60 °C for 12 h. The obtained solid catalyst was labeled MCM-41-pr-ILOH, where pr represents propyl and ILOH represents basic ionic liquid.

[0058] Other steps are the same as in Example 1.

[0059] The reason why Comparative Example 4 has a worse effect than Example 1 is that the amount of 1,2,4-triazole used is halved, the IL loading of the solid catalyst is correspondingly reduced, and the alkalinity decreases.

[0060] Comparative Example 5

[0061] The common basic ionic liquid 1-butyl-3-methylimidazolium chloride was dissolved in anhydrous toluene, and then the MCM-41 support was added, and the mixture was refluxed for 24 h under a nitrogen atmosphere. After cooling to room temperature, the solid product was separated by filtration, thoroughly washed with acetone to remove the excess IL, and vacuum dried at 40 °C for 4 h. Then, the obtained solid precipitate was extracted in a Soxhlet apparatus with a 1:1 (v / v) mixture of diethyl ether / dichloromethane for 6 h. Finally, the solid product was treated with a 0.21 mol / L methanol solution of TMAOH, and the resulting solution was stirred at room temperature for 4 h to exchange chloride ions with hydroxyl anions. The solid catalyst thus prepared was filtered from the reaction mixture, washed several times with ethanol, and then vacuum dried at 60 °C for 12 h. The obtained solid catalyst was labeled MCM-41-pr-ILOH, where pr represents propyl and ILOH represents basic ionic liquid.

[0062] Add 1 g of catalyst and 50 g of isobutyraldehyde into a 500 mL three-necked flask equipped with a stirrer and a reflux device. Conduct the aldol condensation reaction of isobutyraldehyde at 20 °C for 2 h, and then directly heat up to conduct the intramolecular Cannizzaro reaction. Conduct the esterification reaction at 60 °C for 4 h to produce a product mainly containing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in the second stage. Collect 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a distillation column, with the column temperature at 70 °C, the vacuum degree at 7.9×10 -2 MPa, and the reflux ratio at 1:4. Analyze the primary / secondary ester content by gas chromatography.

[0063] Table 1 Comparison of product performance under different process conditions in the examples and comparative examples

[0064]

[0065] Table 1 shows that the solid base catalyst derived from the supported mesoporous ionic liquid of this method has high reactivity towards the raw materials, the solid product is easy to separate during catalysis, does not corrode the equipment, and is an environmentally friendly green catalyst.

[0066] It should be understood that those of ordinary skill in the art can make improvements and changes based on the above description, and all such improvements and changes should fall within the protection scope of the claims of the present invention.

Claims

1. Application of an ionic liquid-derived solid base catalyst in the synthesis of alcohol ester dodecane containing high primary esters, characterized in that: Using isobutyraldehyde as a raw material, 2,2,4-trimethyl-1,3-pentanediol and isobutyric acid are obtained through aldol condensation and Cannizzaro reaction under the condition of an alkaline catalyst. The catalytic esterification reaction is carried out at 60-90 °C to obtain 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate product; The specific preparation steps of the alkaline catalyst are as follows: (1) Add 3-chloropropyltriethoxysilane to 1,2,4-triazole and acetonitrile solvent, and add 1-chlorobutane and anhydrous toluene for nucleophilic substitution; reflux the mixture under a nitrogen atmosphere to form 4-butyl-1-triethoxysilylpropyltriazole chloride; the molar ratio of 1,2,4-triazole, 3-chloropropyltriethoxysilane and 1-chlorobutane is 1:1:1~1:1:4; (2) Dissolve the 4-butyl-1-triethoxysilylpropyltriazole chloride prepared in (1) in anhydrous toluene, then add MCM-41 support, and reflux the mixture under a nitrogen atmosphere; (3) After cooling the mixture in (2) to room temperature, separate the solid product by filtration, wash it with acetone, dry it under vacuum, and extract the solid precipitate with a mixture of ether / dichloromethane (4) Treat the solid precipitate in (3) with a TMAOH methanol solution, stir at room temperature to exchange chloride ions with hydroxyl anions, filter, wash with ethanol, and dry. The obtained solid catalyst is labeled as MCM-41-pr-ILOH, where pr represents propyl and ILOH represents basic ionic liquid.

2. The application according to claim 1, wherein: The volume ratio of the anhydrous toluene and acetonitrile solvent described in step (1) is 1:1~1:5; the concentration of 1,2,4-triazole in acetonitrile is 0.2 mol / L, and it is heated to reflux reaction for 18-24 h under a nitrogen atmosphere.

3. The application according to claim 1, wherein: The concentration of 4-butyl-1-triethoxysilylpropyltriazole chloride in anhydrous toluene described in step (2) is 1~4 g / L, and the loading amount of 4-butyl-1-triethoxysilylpropyltriazole chloride on the MCM-41 support is 1~20 wt%.

4. The application according to claim 1, characterized in that: The vacuum drying conditions in step (3) are drying in vacuum at 40~70 °C for 4~10 h; the volume ratio of ether and dichloromethane is 1:1~1:3; the solid precipitation time is 4~8 h.

5. The application according to claim 1, wherein: The concentration of the TMAOH methanol solution described in step (4) is 0.2 mol / L, and the stirring time at room temperature is 4~8 h; the drying conditions are vacuum drying at 40~70 °C for 8~12 h.

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