Method for preparing ethyl acetate through ethanol dehydrogenation
By using CuZn-based composite metal oxide catalysts, the problems of low ethanol conversion and selectivity in the one-step dehydrogenation of ethanol to ethyl acetate were solved, achieving high selectivity, high conversion of ethyl acetate and stable catalyst performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-10-18
- Publication Date
- 2026-04-21
AI Technical Summary
In existing technologies for the one-step dehydrogenation of ethanol to produce ethyl acetate, the ethanol conversion rate is low or the ethyl acetate selectivity is low, resulting in high production costs, severe equipment corrosion, and environmental pollution.
A CuZn-based composite metal oxide catalyst was used to catalyze the dehydrogenation of ethanol to prepare ethyl acetate via in-situ hydrogen reduction pretreatment. ZnO promoters were introduced into the catalyst to regulate the valence state and acid-base sites of Cu, suppress side reactions, and improve the selectivity of ethyl acetate.
It achieves the production of ethyl acetate with high selectivity and high conversion rate, produces high-purity H2 as a byproduct, has good catalyst stability and long life, reduces production costs and equipment corrosion.
Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing ethyl acetate by dehydrogenation of ethanol, specifically to the preparation of ethyl acetate by direct dehydrogenation of ethanol as a reactant. Background Technology
[0002] Ethyl acetate is a versatile organic solvent widely used in industries such as chemicals, coatings, pharmaceuticals, pesticides, adhesives, colorants, and synthetic fibers. It is an important raw material for organic synthesis, used to synthesize many other organic compounds. In the food, beverage, and tobacco industries, ethyl acetate is widely used as a flavoring agent to improve the taste and quality of products. It also has extensive applications in the cosmetics industry, used to prepare cosmetics and enhance their quality and efficacy. Furthermore, ethyl acetate is widely used in the pharmaceutical industry for the production of certain drugs. Additionally, it can be used to prepare some pharmaceutical intermediates. As a common chemical, ethyl acetate has a wide range of uses and plays an important role in various fields.
[0003] The most widely used method for producing ethyl acetate in the market is the direct esterification reaction of ethanol and acetic acid, which was also the earliest method used in the industrial production of ethyl acetate. This process has the following drawbacks: high reaction temperature, low acetic acid utilization rate, and susceptibility to side reactions. Furthermore, the highly corrosive nature of concentrated sulfuric acid as a catalyst leads to severe equipment corrosion, environmental pollution from waste liquid, and difficulties in treating byproducts, resulting in high production costs. There is an urgent need to develop a low-cost, environmentally friendly, efficient, and stable ethyl acetate production route. The one-step dehydrogenation of ethanol uses only ethanol as a raw material, producing ethyl acetate and hydrogen. The production process is simple, the conditions are mild, the product selectivity is high, and the production cost is low. It also causes minimal corrosion to equipment materials and produces no acidic wastewater or environmental pollution. Therefore, it is a high-yield, non-corrosive, and low-raw-cost synthetic route with promising development prospects. However, existing technologies for preparing ethyl acetate through one-step dehydrogenation of ethanol, such as patent CN117326946 A, suffer from low selectivity for ethyl acetate. Shandong Jinyimeng Group uses ethanol dehydrogenation to prepare ethyl acetate, with an ethanol conversion rate of 60% and an ethyl acetate selectivity of 92%; Shandong Boxing uses ethanol dehydrogenation to prepare ethyl acetate, with an ethanol conversion rate of 60-65% and an ethyl acetate selectivity of 85-90%.
[0004] Although the above methods all utilize ethanol dehydrogenation to prepare ethyl acetate, they suffer from low ethanol conversion rates or low ethyl acetate selectivity. Therefore, developing a solid catalyst system with high reactivity, stability, and high ethyl acetate selectivity is of great significance. Summary of the Invention
[0005] The purpose of this invention is to provide a method for the direct dehydrogenation of ethanol to prepare ethyl acetate. This preparation method has the advantages of simple reaction process, high selectivity and yield, stable catalyst performance, and long reaction lifetime.
[0006] The ethyl acetate involved in this invention is prepared by the following method.
[0007] Ethanol was used as a raw material in a fixed-bed reactor. A CuZn-based composite metal oxide catalyst was packed into the reaction tube. The catalyst was pretreated using an in-situ hydrogen reduction method. Ethanol was fed into the fixed-bed reactor at a temperature of 160℃–260℃, a pressure of 0.3–3 MPa, and a feed mass hourly space velocity (WHSV) of 0.5–4 h⁻¹. -1 The catalyst is prepared from Cu, Zn active metals, and composite metals. The composite metals are one or both of Zr and Ce oxides. The active metal CuO content is 3%–30% (by weight of oxides), the active metal ZnO content is 5%–20% (by weight of oxides), and the remainder is composite metal oxides. A CuZn bimetallic solution of soluble CuZn metal salts is prepared according to the required proportions (by weight of oxides). A soluble composite metal salt is added to the solution, and the mixture is stirred. The pH of the solution is then adjusted to 7.3–10 using an alkaline solution to obtain a turbid liquid. The resulting turbid liquid is crystallized at 60–110℃ for 3–7 hours, and finally, after filtration, washing with water, and drying, the catalyst is obtained.
[0008] This method involves adding ZnO as a promoter to a copper-based catalyst for the dehydrogenation of ethanol to produce ethyl acetate, while simultaneously producing high-purity H2 with a purity >99.5%. The conversion rate can reach up to 80%, and the selectivity for ethyl acetate is as high as 96%.
[0009] The specific technical solution is as follows:
[0010] The reaction process for the dehydrogenation of ethanol to ethyl acetate is as follows: using ethanol as raw material, a catalyst is loaded into a fixed-bed reactor to carry out the reaction;
[0011] The catalyst is a CuZn-based composite metal oxide catalyst.
[0012] The CuZn-based composite metal oxide catalyst is composed of Cu, Zn active metals and composite metals, wherein the content of active metal CuO is 3% to 30% (by weight of oxides), the content of active metal ZnO is 5% to 20% (by weight of oxides), and the remainder is composite metal oxides.
[0013] The active metal CuO content is preferably 7% to 20% (based on the weight of oxides), and the active metal ZnO content is preferably 10% to 20% (based on the weight of oxides).
[0014] The catalyst for the dehydrogenation of ethanol to prepare ethyl acetate contains a composite metal, which is one or both of oxides of Zr and Ce.
[0015] The catalyst is prepared from a Cu-Zn based composite metal oxide catalyst by one of the following methods: co-precipitation, impregnation, hydrothermal method, or sol-gel method; the preferred preparation methods are co-precipitation and hydrothermal method.
[0016] The preparation method of CuZn-based composite metal oxide catalysts using co-precipitation method has a pH value of 7.3-10, preferably 7.5-9.
[0017] When CuZn-based composite metal oxide catalysts are prepared by hydrothermal method, the crystallization temperature is 60-180℃ and the crystallization time is 8-48 hours.
[0018] The CuZn bimetallic solution is prepared by mixing metal salt solutions in a ratio (based on the weight of oxides) of 0.5:1 to 3:1 (preferably 1:1 to 2:1); after drying, the catalyst is prepared and calcined in air at 300 to 600°C (preferably 450 to 550°C) for 1 to 5 hours (preferably 2 to 4 hours).
[0019] The catalyst is pretreated by in-situ reduction, which is carried out at 180–300℃ (preferably 200–280℃) in a hydrogen atmosphere for 0.5–3 h. The ethanol dehydrogenation reaction temperature is 160–260℃, the reaction pressure is 0.3–3 MPa, and the ethanol feed mass hourly space velocity is 0.5–4 h⁻¹. -1 .
[0020] The reaction for the dehydrogenation of ethanol to prepare ethyl acetate uses anhydrous ethanol or an aqueous solution of ethanol as the raw material, with a water content of 1.0% to 10% (by weight) (preferably 3% to 8%). The preferred reaction temperature is 180 to 240°C, the preferred reaction pressure is 0.5 to 2 MPa, and the preferred feed space velocity is 0.8 to 2 h⁻¹. -1 .
[0021] CuZn-based composite metal oxide catalysts for the dehydrogenation of ethanol to ethyl acetate have the following characteristics: (1) By successfully controlling the Cu valence state, acid-base site strength and quantity of the CuZn catalyst through Zn doping, the self-condensation and dehydration process of the side reaction acetaldehyde is suppressed, resulting in a decrease in the selectivity of C4 byproducts and an improvement in the selectivity of ethyl acetate; (2) The introduction of an appropriate amount of Zn can stabilize Cu(I) in the catalyst. With the increase of Cu(I) component content, the selectivity of ethyl acetate is significantly improved, which helps ethanol to selectively generate ethyl acetate through dehydrogenation-condensation reaction; (3) The introduction of composite metal oxides forms a metal eutectic, which disperses the active Cu component, avoids the high-temperature sintering of Cu ions during the reaction, and improves the stability and lifespan of the catalyst.
[0022] The advantages of this method are: (1) CuZn-based composite metal oxide catalysts are simple to prepare, have good stability, and long catalyst life. The catalyst activity can be restored through calcination and reduction. (2) Zn doping promotes the dispersion and formation of Cu active components, effectively promotes the selective generation of ethyl acetate, and can also inhibit the formation of strong acid sites, thereby inhibiting the generation of byproducts butanone and butanol. (3) The process of catalytic dehydrogenation of ethanol to ethyl acetate in this catalytic system shows certain advantages. The selectivity of the target product is as high as 95% or more, and hydrogen is produced simultaneously, resulting in high atom economy. Detailed Implementation
[0023] To provide a more detailed description of the present invention, several specific implementation examples are given below, but the present invention is not limited to these embodiments.
[0024] The reaction was carried out in a fixed-bed reactor. The catalyst was granulated, sieved, and then packed into the fixed-bed reactor for ethanol dehydrogenation. The resulting reaction products were analyzed and calculated using gas chromatography.
[0025] Example 1
[0026] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. Crystallization was carried out in an oil bath at 80 °C for 5 h, followed by filtration and washing with ultrapure water until neutral. After drying at 100 °C, the catalyst was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (WHSV) of 0.5 h⁻¹ for the anhydrous ethanol feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 81%, and the selectivity of ethyl acetate was 93%.
[0027] Example 2
[0028] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. Crystallization was carried out in an oil bath at 80 °C for 5 h, followed by filtration and washing with ultrapure water until neutral. After drying at 100 °C, the catalyst was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (WHSV) of 1.5 h⁻¹ for the anhydrous ethanol feedstock. -1At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 67%, and the selectivity of ethyl acetate was 96%.
[0029] Example 3
[0030] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L Na₂CO₃ aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO₂ catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 64%, and the selectivity of ethyl acetate was 62%.
[0031] Example 4
[0032] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L KOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (WHSV) of 1 h⁻¹ for the anhydrous ethanol feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 73%, and the selectivity of ethyl acetate was 87%.
[0033] Example 5
[0034] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1At 240℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 83%, and the selectivity of ethyl acetate was 89%.
[0035] Example 6
[0036] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1 At 180℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 59%, and the selectivity of ethyl acetate was 92%.
[0037] Example 7
[0038] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1 At 220℃ and atmospheric pressure, after 2 hours of reaction, chromatographic analysis showed that the conversion rate of ethanol was 82% and the selectivity of ethyl acetate was 48%.
[0039] Example 8
[0040] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1At 220℃ and a reaction pressure of 0.5 MPa, samples were taken for chromatographic analysis after 2 hours of reaction. The conversion rate of ethanol was 79%, and the selectivity of ethyl acetate was 88%.
[0041] Example 9
[0042] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1 At 220℃ and a reaction pressure of 2 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 74%, and the selectivity of ethyl acetate was 93%.
[0043] Example 10
[0044] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 78%, and the selectivity of ethyl acetate was 95%.
[0045] Example 11
[0046] 4.16 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 38.13 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 10 wt% CuO-10 wt% ZnO-80 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (WHSV) of 1 h⁻¹ for the anhydrous ethanol feedstock. -1At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 65%, and the selectivity of ethyl acetate was 88%.
[0047] Example 12
[0048] 4.16 g of copper nitrate trihydrate, 7.51 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 10 wt% CuO-15 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 67%, and the selectivity of ethyl acetate was 90%.
[0049] Example 13
[0050] 8.31 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 33.42 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 20 wt% CuO-10 wt% ZnO-70 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with the mass hourly space velocity (WHSV) of the anhydrous ethanol feedstock being 1 h⁻¹. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 81%, and the selectivity of ethyl acetate was 83%.
[0051] Example 14
[0052] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved through a 40-60 mesh sieve, and packed into a fixed-bed reactor. In-situ reduction with hydrogen gas at 220 °C at 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of 1 h⁻¹ for the 95% ethanol aqueous solution.-1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 76%, and the selectivity of ethyl acetate was 95%.
[0053] Example 15
[0054] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 6 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (WHSV) of 1 h⁻¹ for the anhydrous ethanol feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 46%, and the selectivity of ethyl acetate was 73%.
[0055] Example 16
[0056] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 10 with NaOH (3 mol / L) aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with the mass hourly space velocity (WHSV) of the anhydrous ethanol feedstock being 1 h⁻¹. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 73%, and the selectivity of ethyl acetate was 86%.
[0057] Example 17
[0058] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 70 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (WHSV) of 1 h⁻¹ for the anhydrous ethanol feedstock.-1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 76%, and the selectivity of ethyl acetate was 93%.
[0059] Example 18
[0060] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 90 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with the mass hourly space velocity (WHSV) of the anhydrous ethanol feedstock being 1 h⁻¹. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 77%, and the selectivity of ethyl acetate was 92%.
[0061] Example 19
[0062] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved through a 40-60 mesh sieve, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 180 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 53%, and the selectivity of ethyl acetate was 68%.
[0063] Example 20
[0064] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 35.81 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 280 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock.-1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 75%, and the selectivity of ethyl acetate was 90%.
[0065] Example 21
[0066] 6.25 g of copper nitrate trihydrate, 5.00 g of zinc nitrate hexahydrate, and 25.88 g of cerium nitrate hexahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-10 wt% ZnO-75 wt% CeO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 280 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (WHSV) of 1 h⁻¹ for the anhydrous ethanol feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 74%, and the selectivity of ethyl acetate was 90%.
[0067] Comparative Example 1
[0068] 6.25 g of copper nitrate trihydrate and 40.58 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-85 wt% ZrO2 catalyst. The catalyst was granulated, sieved through a 40-60 mesh sieve, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with the mass hourly space velocity (WHSV) of the anhydrous ethanol feedstock being 1 h⁻¹. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 72%, and the selectivity of ethyl acetate was 58%.
[0069] Comparative Example 2
[0070] 5.00 g of zinc nitrate hexahydrate and 42.97 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with NaOH (3 mol / L) aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 10 wt% ZnO-90 wt% ZrO2 catalyst. The catalyst was granulated, sieved through a 40-60 mesh sieve, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 220 °C and 10 mL / min was performed for 1 h, with the mass hourly space velocity (WHSV) of the anhydrous ethanol feedstock being 1 h⁻¹. -1At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 31%, and the selectivity of ethyl acetate was 51%.
[0071] Comparative Example 3
[0072] 6.25 g of copper nitrate trihydrate, 1.50 g of zinc nitrate hexahydrate, and 39.15 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-3 wt% ZnO-82 wt% ZrO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 280 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 43%, and the selectivity of ethyl acetate was 61%.
[0073] Comparative Example 4
[0074] 6.25 g of copper nitrate trihydrate, 15.00 g of zinc nitrate hexahydrate, and 26.26 g of zirconium nitrate pentahydrate were weighed and dissolved in 270 mL of water. The pH was adjusted to 8 with a 3 mol / L NaOH aqueous solution. The mixture was crystallized in an oil bath at 80 °C for 5 h, and then filtered and washed with ultrapure water until neutral. After drying at 100 °C, it was calcined in air at 500 °C for 3 h to obtain a 15 wt% CuO-30 wt% ZnO-55 wt% CeO2 catalyst. The catalyst was granulated, sieved to a 40-60 mesh, and packed into a fixed-bed reactor. In-situ reduction with hydrogen at 280 °C and 10 mL / min was performed for 1 h, with a mass hourly space velocity (MHSV) of anhydrous ethanol as the feedstock. -1 At 220℃ and a reaction pressure of 1 MPa, samples were taken for chromatographic analysis after 2 hours. The conversion rate of ethanol was 73%, and the selectivity of ethyl acetate was 41%.
[0075] The above descriptions are merely a few embodiments of this application and do not constitute any limitation on this application. Any changes or modifications made to the technical content disclosed above without departing from the scope of the technical solution of this application are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.
Claims
1. A method for preparing ethyl acetate by dehydrogenation of ethanol, characterized in that: The reaction process for the dehydrogenation of ethanol to ethyl acetate is as follows: using ethanol as raw material, a catalyst is loaded into a fixed-bed reactor to carry out the reaction; The catalyst is a CuZn-based composite metal oxide catalyst.
2. The method according to claim 1, characterized in that: The CuZn-based composite metal oxide catalyst is composed of Cu, Zn active metals and composite metals, wherein the content of active metal CuO is 3% to 30% (by weight of oxides), the content of active metal ZnO is 5% to 20% (by weight of oxides), and the remainder is composite metal oxides.
3. The method according to claim 2, characterized in that: The active metal CuO content is preferably 7% to 20% (based on the weight of oxides), and the active metal ZnO content is preferably 10% to 20% (based on the weight of oxides).
4. The method according to claim 1, 2, or 3, characterized in that: The catalyst for the dehydrogenation of ethanol to prepare ethyl acetate contains a composite metal, which is one or both of oxides of Zr and Ce.
5. The method according to claim 1, 2, or 3, characterized in that: The catalyst is prepared from a Cu-Zn based composite metal oxide catalyst by one of the following methods: co-precipitation, impregnation, hydrothermal method, or sol-gel method; the preferred preparation methods are co-precipitation and hydrothermal method.
6. The method according to claim 1 or 5, characterized in that: The preparation method of CuZn-based composite metal oxide catalysts using co-precipitation method has a pH value of 7.3-10, preferably 7.5-9.
7. The method according to claim 1 or 5, characterized in that: When CuZn-based composite metal oxide catalysts are prepared by hydrothermal method, the crystallization temperature is 60-180℃ and the crystallization time is 8-48 hours.
8. The method according to claim 6, characterized in that: The CuZn bimetallic solution is prepared by mixing metal salt solutions in a ratio (based on the weight of oxides) of 0.5:1 to 3:1 (preferably 1:1 to 2:1); after drying, the catalyst is prepared and calcined in air at 300 to 600°C (preferably 450 to 550°C) for 1 to 5 hours (preferably 2 to 4 hours).
9. The method according to claim 1, characterized in that: The catalyst is pretreated by in-situ reduction, which is carried out at 180–300℃ (preferably 200–280℃) in a hydrogen atmosphere for 0.5–3 h. The ethanol dehydrogenation reaction temperature is 160–260℃, the reaction pressure is 0.3–3 MPa, and the ethanol feed mass hourly space velocity is 0.5–4 h⁻¹. -1 .
10. The method according to claim 1 or 9, characterized in that: The reaction for the dehydrogenation of ethanol to prepare ethyl acetate uses anhydrous ethanol or an aqueous solution of ethanol as the raw material, with a water content of 1.0% to 10% (by weight) (preferably 3% to 8%). The preferred reaction temperature is 180 to 240°C, the preferred reaction pressure is 0.5 to 2 MPa, and the preferred feed space velocity is 0.8 to 2 h⁻¹. -1 .