A catalyst for synthesizing ethyl acetate and a preparation method thereof

Abstract

The application discloses a kind of catalyst for synthesizing ethyl acetate and preparation method thereof, belong to catalyst technical field.The preparation method of the catalyst for synthesizing ethyl acetate, comprising the following steps: step 1, amino SiO2 Microspheres are added to xylene, stirring, under N2 Atmosphere, heating to xylene reflux temperature after reaction, octafluoro methyl methacrylate is added, constant temperature reaction 2h is continued, stop reaction, suction filtration, after drying modified SiO2 Microspheres are obtained;Step 2, at 0 DEG C, modified SiO2 Microspheres are added to dichloromethane, stirring is uniformly after adding chlorosulfonic acid, continuous stirring, after reaction, washing, filtration, vacuum drying catalyst is obtained.The catalyst prepared in the application has high catalytic activity and high stability, and the catalyst is simple to separate from the product, does not corrode equipment, has less three wastes pollution, simple post-treatment process and the advantages of being convenient for industrial production, conforms to the concept of green environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a catalyst for the synthesis of ethyl acetate and its preparation method. Background Technology

[0002] Ethyl acetate, also known as ethyl acetate, is a colorless, transparent liquid with a fruity aroma. It is a major industrial solvent and is also commonly used as a binder or extractant in the production of various related products, making it a very common chemical raw material. The main production method for ethyl acetate is the direct esterification process using ethanol and acetic acid as raw materials and concentrated sulfuric acid as a catalyst. However, due to the strong oxidizing properties of sulfuric acid, high-quality equipment is required. Furthermore, the acidic waste liquid generated by concentrated sulfuric acid during the post-reaction process causes serious environmental pollution, contradicting the principles of environmental friendliness and green chemistry, and leading to a series of post-treatment problems, thus increasing production costs.

[0003] Therefore, developing a catalyst that is suitable for the synthesis of ethyl acetate and is both environmentally friendly and highly efficient has become an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a catalyst for the synthesis of ethyl acetate and a method for preparing the same, so as to solve the problems mentioned in the background art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing a catalyst for the synthesis of ethyl acetate includes the following steps:

[0007] Step 1: Add aminated SiO2 microspheres to xylene, stir, and react under N2 atmosphere by heating to the xylene reflux temperature. Add octafluoroamyl methacrylate, and continue the reaction at a constant temperature for 2 hours. Stop the reaction, filter, and dry to obtain modified SiO2 microspheres.

[0008] Step 2: At 0℃, the modified SiO2 microspheres are added to dichloromethane and stirred until homogeneous. Then, chlorosulfonic acid is added and stirred continuously. After the reaction is complete, the mixture is washed, filtered, and vacuum dried to obtain the catalyst.

[0009] Furthermore, in step 1, the ratio of aminated SiO2 microspheres, xylene, and octafluoropentyl methacrylate is 1g:30mL:0.1-0.25g; in step 2, the ratio of modified SiO2 microspheres, dichloromethane, and chlorosulfonic acid is 1g:150mL:5-6mL.

[0010] Furthermore, in step 2, the filtrate is washed until it is neutral, and the vacuum drying temperature is 120-150℃, and the drying time is 6-8 hours.

[0011] Furthermore, the aminated SiO2 microspheres in step 1 are prepared through the following steps:

[0012] The silane coupling agent KH-550 was dissolved in an aqueous ethanol solution and stirred to disperse, thus obtaining a hydrolyzed solution of the silane coupling agent KH-550. Then, SiO2 microspheres were added to the hydrolyzed solution of the silane coupling agent KH-550, ultrasonically dispersed, heated and stirred, centrifuged, washed, and dried to obtain aminated SiO2 microspheres.

[0013] Furthermore, the volume ratio of silane coupling agent KH-550 to ethanol aqueous solution is 1 mL:15 mL; the volume ratio of SiO2 microspheres to silane coupling agent KH-550 hydrolysis solution is 2 g:15 mL; and the volume ratio of ethanol to deionized water in the ethanol aqueous solution is 10:1.

[0014] Furthermore, SiO2 microspheres are prepared through the following steps:

[0015] Ammonia and anhydrous ethanol were added to deionized water and stirred until homogeneous. Then, tetraethyl orthosilicate was added and stirred again. After centrifugation, washing, and drying, solid SiO2 microspheres were obtained. These solid SiO2 microspheres were then added to deionized water and dispersed until homogeneous. Next, hexadecyltrimethylammonium bromide and sodium carbonate were added, and the mixture was heated to 35-50℃ and reacted for 10-20 hours. After the reaction, the suspension was centrifuged, washed, dried, and sieved to obtain SiO2 microspheres. The SiO2 microspheres prepared in this method have a hollow porous structure, a higher specific surface area, and contain a greater number of polar oxygen-containing groups. This provides more reaction sites for subsequent chemical modification of the SiO2 microspheres and the preparation of sulfonated SiO2 microsphere catalysts, thereby further increasing the number of active groups and surface acidity of the sulfonated SiO2 microsphere catalysts, resulting in better catalytic performance in both synthesis and catalytic reactions.

[0016] Furthermore, the ratio of ammonia, anhydrous ethanol, deionized water, and tetraethyl orthosilicate is 10 mL: 30 mL: 30 mL: 1 mL; the ratio of SiO2 solid microspheres, deionized water, hexadecyltrimethylammonium bromide, and sodium carbonate is 1 g: 15 mL: 0.2 g: 4 g.

[0017] Furthermore, during the preparation of SiO2 microspheres, the sieve mesh size is 100-150 mesh.

[0018] A catalyst for the synthesis of ethyl acetate is prepared by the above steps.

[0019] The beneficial effects of this invention are:

[0020] The catalyst prepared in this invention has the advantages of high catalytic activity and high stability, simple separation of catalyst and product, no corrosion to equipment, few side reactions, little pollution from waste, simple post-processing and easy industrial production. It also has the advantages of being reusable. It is a catalyst with promising industrial application prospects.

[0021] The catalyst in this invention uses hollow porous SiO2 microspheres with high porosity as the catalyst matrix. After modification with KH-550, amino groups are introduced on the surface of the microspheres as active reaction sites. This reaction with octafluoropentyl methacrylate imparts hydrophobic properties to the SiO2 microspheres, reducing their surface energy and thus minimizing particle aggregation and improving their dispersion in solvents. Finally, the sulfonated SiO2 microspheres, after chlorosulfonic acid sulfonation, possess highly active, strongly acidic, high-density -SO3H atoms as catalytic centers. These microspheres exhibit significant catalytic performance in the synthesis of ethyl acetate, greatly extending the catalytic time and allowing for repeated use, thus expanding the catalyst's application range.

[0022] The catalyst prepared in this invention significantly shortens the reaction time and improves the catalytic efficiency compared with the traditional catalyst concentrated sulfuric acid, and does not corrode the process equipment. In the synthesis of ethyl acetate in this invention, the yield of ethyl acetate can still reach 48.8% after being reused three times, which shows excellent reusability, low cost, and conforms to the concept of green environmental protection. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] The SiO2 microspheres used in this invention are prepared through the following steps:

[0025] 10 mL of ammonia and 30 mL of anhydrous ethanol were added to 30 mL of deionized water and stirred until homogeneous. Then, 1 mL of tetraethyl orthosilicate was added and the mixture was stirred for 3 h. After centrifugation, washing and drying, solid SiO2 microspheres were obtained. 1 g of the obtained solid SiO2 microspheres were added to 15 mL of deionized water and dispersed until homogeneous. Then, 0.2 g of hexadecyltrimethylammonium bromide and 4 g of sodium carbonate were added. The mixture was heated to 36 °C and shaken for 18 h. After the reaction was completed, the suspension was centrifuged, washed, dried and passed through a 120-mesh sieve to obtain SiO2 microspheres.

[0026] The aminated SiO2 microspheres used in this invention are prepared through the following steps:

[0027] Dissolve 1 mL of silane coupling agent KH-550 in 15 mL of ethanol aqueous solution, stir and disperse to obtain silane coupling agent KH-550 hydrolysis solution; then add 2 g of SiO2 microspheres to 15 mL of silane coupling agent KH-550 hydrolysis solution, ultrasonically disperse evenly, heat and stir, centrifuge, wash, and dry to obtain aminated SiO2 microspheres.

[0028] Example 1

[0029] This embodiment provides a catalyst for the synthesis of ethyl acetate, and the preparation steps are as follows:

[0030] Step 1: Add 1g of aminated SiO2 microspheres to 30mL of xylene, stir, and react under N2 atmosphere by heating to the xylene reflux temperature. Add 0.1g of octafluoroamyl methacrylate, and continue the reaction at a constant temperature for 2h. Stop the reaction, filter, and dry to obtain modified SiO2 microspheres.

[0031] Step 2: At 0℃, add 1g of modified SiO2 microspheres to 150mL of dichloromethane, stir evenly, then add 5mL of chlorosulfonic acid and continue stirring for 12h. After the reaction is complete, wash with anhydrous dichloromethane until the filtrate is neutral, filter, and dry the solid in a vacuum oven at 120℃ for 8h to obtain the catalyst.

[0032] Example 2

[0033] This embodiment provides a catalyst for the synthesis of ethyl acetate, and the preparation steps are as follows:

[0034] Step 1: Add 1g of aminated SiO2 microspheres to 30mL of xylene, stir, and react under N2 atmosphere by heating to the xylene reflux temperature. Add 0.18g of octafluoroamyl methacrylate, and continue the reaction at a constant temperature for 2h. Stop the reaction, filter, and dry to obtain modified SiO2 microspheres.

[0035] Step 2: At 0℃, add 1g of modified SiO2 microspheres to 150mL of dichloromethane, stir evenly, then add 5mL of chlorosulfonic acid and continue stirring for 12h. After the reaction is complete, wash with anhydrous dichloromethane until the filtrate is neutral, filter, and dry the solid in a vacuum oven at 120℃ for 8h to obtain the catalyst.

[0036] Example 3

[0037] This embodiment provides a catalyst for the synthesis of ethyl acetate, and the preparation steps are as follows:

[0038] Step 1: Add 1g of aminated SiO2 microspheres to 30mL of xylene, stir, and react under N2 atmosphere by heating to the xylene reflux temperature. Add 0.25g of octafluoroamyl methacrylate, and continue the reaction at a constant temperature for 2h. Stop the reaction, filter, and dry to obtain modified SiO2 microspheres.

[0039] Step 2: At 0℃, add 1g of modified SiO2 microspheres to 150mL of dichloromethane, stir evenly, then add 5mL of chlorosulfonic acid and continue stirring for 12h. After the reaction is complete, wash with anhydrous dichloromethane until the filtrate is neutral, filter, and dry the solid in a vacuum oven at 120℃ for 8h to obtain the catalyst.

[0040] Example 4

[0041] This embodiment provides a catalyst for the synthesis of ethyl acetate, and the preparation steps are as follows:

[0042] Step 1: Add 1g of aminated SiO2 microspheres to 30mL of xylene, stir, and react under N2 atmosphere by heating to the xylene reflux temperature. Add 0.18g of octafluoroamyl methacrylate, and continue the reaction at a constant temperature for 2h. Stop the reaction, filter, and dry to obtain modified SiO2 microspheres.

[0043] Step 2: At 0℃, 1g of modified SiO2 microspheres were added to 150mL of dichloromethane and stirred until homogeneous. Then, 6mL of chlorosulfonic acid was added and the mixture was stirred continuously for 12h. After the reaction was completed, the mixture was washed with anhydrous dichloromethane until the filtrate was neutral. The mixture was then filtered, and the solid was dried in a vacuum oven at 150℃ for 6h to obtain the catalyst.

[0044] Comparative Example 1

[0045] Compared to Example 1, in step 1, no intermediate modification operation is performed on the aminated SiO2 microspheres, and the catalyst preparation steps are as follows:

[0046] Step 1: Add 1g of aminated SiO2 microspheres to 30mL of xylene, stir, and react under N2 atmosphere by heating to the xylene reflux temperature. Continue the reaction at a constant temperature for 2h, then stop the reaction, filter, and dry to obtain modified SiO2 microspheres.

[0047] Step 2: At 0℃, add 1g of modified SiO2 microspheres to 150mL of dichloromethane, stir evenly, then add 5mL of chlorosulfonic acid and continue stirring for 12h. After the reaction is complete, wash with anhydrous dichloromethane until the filtrate is neutral, filter, and dry the solid in a vacuum oven at 120℃ for 8h to obtain the catalyst.

[0048] Comparative Example 2

[0049] This comparative example uses commercially available concentrated sulfuric acid as a catalyst for the synthesis of ethyl acetate.

[0050] Examples 1-4 and Comparative Examples 1-2 were applied and tested:

[0051] Add 9.5 mL of anhydrous ethanol, 6 mL of glacial acetic acid, 2 g of the catalyst prepared in the examples and comparative examples, and a few boiling chips to a dry three-necked flask. After installing a reflux device, heat to 85 °C under stirring and react for a period of time. After the experiment, filter to obtain the crude product, dry it with anhydrous magnesium sulfate, and use a glass sampler to collect the mixed solution in a sample vial for gas chromatography analysis (using a GC-2014 gas chromatograph). Record the reaction time and ethyl acetate yield, and test its catalytic performance. The test results are shown in Table 1.

[0052] Table 1

[0053]

[0054] As shown in Table 1, compared with Comparative Examples 1-2, the catalysts prepared in Examples 1-4 of this invention significantly shorten the reaction time in the synthesis of ethyl acetate, and the yield of ethyl acetate can reach 82.8%. Furthermore, after being reused three times, the yield of ethyl acetate still reaches 48.8%. Therefore, the catalysts prepared in this invention have high catalytic activity and high reusability, greatly improving the efficiency of ethyl acetate synthesis and conforming to the concept of green environmental protection.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a catalyst for the synthesis of ethyl acetate, characterized in that, Includes the following steps: Step 1: Add aminated SiO2 microspheres to xylene, stir, and react under N2 atmosphere by heating to the xylene reflux temperature. Add octafluoroamyl methacrylate and continue the reaction at a constant temperature for 2 hours. Stop the reaction, filter, and dry to obtain modified SiO2 microspheres. The ratio of aminated SiO2 microspheres, xylene, and octafluoroamyl methacrylate in Step 1 is 1g:30mL:0.1-0.25g. Step 2: At 0℃, add modified SiO2 microspheres to dichloromethane, stir until homogeneous, then add chlorosulfonic acid and continue stirring. After the reaction is complete, wash until the filtrate is neutral, filter, and vacuum dry to obtain the catalyst. The ratio of modified SiO2 microspheres, dichloromethane, and chlorosulfonic acid in Step 2 is 1g:150mL:5-6mL; the vacuum drying temperature is 120-150℃, and the drying time is 6-8h. The aminated SiO2 microspheres described in step 1 are prepared by the following steps: silane coupling agent KH-550 is dissolved in an ethanol aqueous solution, stirred and dispersed to obtain a hydrolysate of silane coupling agent KH-550; then, SiO2 microspheres are added to the hydrolysate of silane coupling agent KH-550, ultrasonically dispersed, heated and stirred, centrifuged, washed, and dried to obtain aminated SiO2 microspheres; the volume ratio of silane coupling agent KH-550 to ethanol aqueous solution is 1 mL:15 mL; the volume ratio of SiO2 microspheres to silane coupling agent KH-550 hydrolysate is 2 g:15 mL; wherein the volume ratio of ethanol to deionized water in the ethanol aqueous solution is 10:

1. The SiO2 microspheres were prepared by the following steps: ammonia and anhydrous ethanol were added to deionized water and stirred evenly. Then, tetraethyl orthosilicate was added and stirred. After centrifugation, washing, and drying, solid SiO2 microspheres were obtained. The obtained solid SiO2 microspheres were then added to deionized water and dispersed evenly. Then, hexadecyltrimethylammonium bromide and sodium carbonate were added, and the mixture was heated to 35-50℃ and reacted for 10-20 hours. After the reaction, the suspension was centrifuged, washed, dried, and sieved to obtain SiO2 microspheres. The ratio of ammonia, anhydrous ethanol, deionized water, and tetraethyl orthosilicate was 10mL:30mL:30mL:1mL. The ratio of solid SiO2 microspheres, deionized water, hexadecyltrimethylammonium bromide, and sodium carbonate was 1g:15mL:0.2g:4g. The sieve mesh size was 100-150 mesh.

2. A catalyst for the synthesis of ethyl acetate, characterized in that, It is prepared by the preparation method described in claim 1.

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