CN116162023B

CN116162023B - Method for preparing ethyl acetate by dehydrogenation condensation of ethanol

Info

Publication number: CN116162023B
Application number: CN202111401014.0A
Authority: CN
Inventors: 王峰; 王业红; 张健; 张志鑫
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2021-11-24
Filing date: 2021-11-24
Publication date: 2025-02-11
Anticipated expiration: 2041-11-24
Also published as: CN116162023A

Abstract

本发明涉及一种乙醇脱氢缩合制乙酸乙酯的方法。该方法采用乙醇或是乙醇水溶液作为反应物，在铜基酸碱双功能催化剂的催化作用下，通过无氧脱氢缩合反应制备乙酸乙酯。其反应条件如下：该反应在固定床反应器中常压下进行，反应温度220～350℃，乙醇进料质量空速0.5～3.5h^‑1。该方法的特征是：以多相铜基酸碱双功能为催化剂，催化剂无毒，制备简单且催化乙醇高选择性生成乙酸乙酯，同时联产氢气，乙酸乙酯的最高选择性可达到95％，乙醇的转化率最高达到75％，且具有较好的稳定性。The present invention relates to a method for preparing ethyl acetate by dehydrogenation condensation of ethanol. The method uses ethanol or ethanol aqueous solution as a reactant, and prepares ethyl acetate by oxygen-free dehydrogenation condensation reaction under the catalytic action of a copper-based acid-base bifunctional catalyst. The reaction conditions are as follows: the reaction is carried out in a fixed bed reactor under normal pressure, the reaction temperature is 220-350°C, and the ethanol feed mass space velocity is 0.5-3.5h ^‑1 . The method is characterized in that: a multiphase copper-based acid-base bifunctional catalyst is used as a catalyst, the catalyst is non-toxic, the preparation is simple, and ethanol is catalyzed to generate ethyl acetate with high selectivity, and hydrogen is co-produced at the same time. The highest selectivity of ethyl acetate can reach 95%, and the highest conversion rate of ethanol can reach 75%, and the method has good stability.

Description

Method for preparing ethyl acetate by alcohol dehydrogenation condensation

Technical Field

The invention relates to a preparation method of ethyl acetate, in particular to a preparation method of ethyl acetate by taking ethanol as a reactant through a direct dehydrogenation condensation process.

Background

Ethyl acetate is one of the most widely used fatty acid esters, has excellent dissolution performance, is an important green industrial solvent which is quick-dried, is widely used in the production process of chemical products such as acetate fiber, ethyl fiber, chlorinated rubber, vinyl resin, synthetic rubber, paint and the like, is used as an industrial solvent in products such as paint, adhesive, ethylcellulose, artificial leather, linoleum coloring agent, artificial fiber and the like, is used as an adhesive in the production of printing ink and artificial pearl, is used as an extracting agent in the production of products such as medicines and organic acids and is used as a spice raw material, and is a main raw material of fruit essence such as pineapple, banana and strawberry, spice such as whiskey and cream.

The production method of ethyl acetate is mainly based on the traditional esterification method. Although domestic large-scale methanol oxo-acetic acid enterprises or enterprises with bioethanol devices provide rich and cheap acetic acid and ethanol raw materials, the esterification process still has a plurality of defects of low utilization rate of acetic acid, unfriendly environment and the like. Although the production process is relatively mature, the technical threshold is low, and the process and the production technology tend to be stable, the prior art cannot meet the demands more and more from the market demands and the interests of manufacturers. Therefore, the development of the ethyl acetate production process with high efficiency, energy conservation and small environmental load has practical significance. The route for preparing the ethyl acetate by the alcohol dehydrogenation condensation one-step method has high economy and is environment-friendly, and is an ideal route for preparing the ethyl acetate. The method for preparing ethyl acetate by alcohol dehydrogenation condensation takes alcohol as a raw material, and synthesizes the ethyl acetate by one-step dehydrogenation through gas-solid phase reaction, and has the advantages of simple flow, green process and easy separation of products and catalysts. In 2001, davy uses a toxic copper-chromium catalyst to perform a reaction for preparing ethyl acetate by alcohol dehydrogenation condensation, the selectivity of ethyl acetate is about 94%, but the conversion rate of alcohol is only about 27%. The selectivity of ethyl acetate of copper zinc aluminum zirconium catalyst adopted by Japan asphyxin petrochemical company is 90-95%, but the ethanol conversion rate is 45%.

Although the catalyst realizes the preparation of ethyl acetate by alcohol dehydrogenation condensation, the adopted catalyst has low conversion rate of toxic or alcohol. Therefore, the development of a solid catalyst system which is nontoxic, easy to obtain, high in reaction activity and good in selectivity has important significance.

Disclosure of Invention

The method has the significance of overcoming the defects existing in the current process of preparing the ethyl acetate by directly dehydrogenating and condensing the ethanol. The preparation method has the advantages of simple reaction process, non-toxic catalyst, high selectivity to ethyl acetate, good stability and long service life.

The ethyl acetate according to the present invention is prepared by the following scheme.

Ethanol is used as a raw material, the reaction is carried out in a fixed bed reactor, a multiphase copper-based acid-base bifunctional catalyst is filled in a reaction tube, and then the reaction tube is placed in the fixed bed reactor, wherein the reaction temperature is 220-350 ℃. The copper-based acid-base bifunctional catalyst consists of active Cu and acid-base metal oxide, wherein the acid-base bifunctional catalyst is one, two or more of zirconium oxide, yttrium oxide, ytterbium oxide, indium oxide, tungsten oxide, scandium oxide, tantalum oxide, niobium oxide, gallium oxide, tin oxide and aluminum oxide, and the alkaline oxide is one, two or more of zinc oxide, cerium oxide, lanthanum oxide, praseodymium oxide, magnesium oxide and strontium oxide. The copper-based acid-base bifunctional catalyst comprises 5-35% of active metal Cu (by weight). The content of the active metal Cu in the copper-based acid-base bifunctional catalyst is preferably 10-25% (by weight). The content of the acidic metal is 45-90 wt% (calculated on the basis of weight). The thickness of the catalyst bed layer filled in the reaction tube is 5 cm-30 cm, the reaction is normal pressure, and the feeding mass airspeed of the ethanol is 0.5-3.5 h ^-1. The preferable reaction condition is that the thickness of a catalyst bed layer in the reaction tube is 10 cm-25 cm, and the space velocity of ethanol feeding mass is 0.5-3.5 h ^-1. The ethanol can be absolute ethanol or ethanol water solution, and the water content is 1.0% -10% (by weight). The reaction temperature for preparing ethyl acetate by alcohol dehydrogenation and condensation is 220-260 ℃.

The heterogeneous copper-based acid-base dual-function catalyst is used for catalyzing alcohol dehydrogenation condensation to prepare ethyl acetate and has the characteristics that (1) the introduction of active Cu promotes alcohol dehydrogenation, (2) a suitable Lewis site on the surface of an oxide carrier is derived from coordination unsaturated metal ions on the surface, and the site acts on one hand with the active Cu species to generate electron transfer, so that the active Cu species is dispersed, the sintering of Cu ions in the reaction process is avoided, the stability is improved, the dehydrogenation activity of Cu is partially inhibited, the excessive dehydrogenation of alcohol is avoided, thereby improving the dehydrogenation selectivity, (3) the acid-base balance in the heterogeneous copper-based acid-base dual-function catalyst is critical, the excessive acid initiates alcohol dehydration side reaction, the excessive basic initiates excessive dehydrogenation to decompose alcohol, and the balance of acid-base site can promote the condensation of acetaldehyde obtained by alcohol dehydrogenation and alcohol into hemiacetal, so that the ethyl acetate is obtained by dehydrogenation. Wherein the combination and the content of metal oxides in the heterogeneous copper-based acid-base bifunctional catalyst are critical factors.

The method has the advantages that (1) the multiphase copper-based acid-base bifunctional catalyst is used for catalyzing alcohol to be dehydrogenated and condensed to prepare ethyl acetate, the catalyst is simple to prepare and high in efficiency to catalyze the reaction, and the catalyst can be activated and regenerated through simple roasting and reduction operations. (2) The process for preparing ethyl acetate by catalyzing alcohol dehydrogenation condensation by the catalytic system has certain superiority, the selectivity of target products is up to 95%, the conversion rate is up to 75%, and hydrogen is coproduced.

Detailed Description

For further detailed description of the present invention, several specific embodiments are given below, but the present invention is not limited to these embodiments.

Carrying out reaction in a fixed bed reactor, filling a catalyst in a reaction tube, and then placing the reaction tube in the fixed bed reactor;

Example 1

10Wt% Cu-80wt% ZrO ₂-10wt％CeO₂ was prepared by co-precipitation. The specific procedure was as follows, weighing 7.6g of copper nitrate trihydrate, 5.0g of cerium nitrate hexahydrate and 30.0g of zirconyl nitrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (nitrogen flow rate is 30 ml/min) to obtain 10wt% Cu-80wt% ZrO ₂-10wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, and filling a 15cm bed layer, wherein the raw material is 5% ethanol water solution (weight concentration, the same applies below), and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 2

10Wt% Cu-80wt% in ₂O₃-10wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 5.0g of cerium nitrate hexahydrate and 34.6g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) and obtaining 10wt percent Cu-80wt percent in ₂O₃-10wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 3

10Wt% Cu-80wt% in ₂O₃-10wt％PrO₂ was prepared by co-precipitation. The specific operation is that 3.0g of copper nitrate trihydrate, 5.0g of praseodymium nitrate hydrate and 34.6g of indium nitrate hydrate are weighed and dissolved in 200 ml of water, and the pH value is regulated to be 10 by NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) and obtaining 10wt percent Cu-80wt percent in ₂O₃-10wt％PrO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 4

The preparation of 10wt% Cu-10wt% La ₂O₃-80wt％ZrO₂ was carried out by coprecipitation. The method comprises the following steps of weighing 3.0g of copper nitrate trihydrate, 30.0g of zirconyl nitrate, 5.4g of lanthanum nitrate hydrate and 15.0g of zirconyl nitrate, dissolving the copper nitrate trihydrate and the zirconyl nitrate in 200 ml of water, and adjusting the pH value to be 10 by using an aqueous solution of NaOH (3 mol/L). Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) to obtain 10wt% Cu-10wt% La ₂O₃-80wt％ZrO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 5

10Wt% Cu-10wt% ZnO-80wt% ZrO ₂ was prepared by coprecipitation. The specific procedure was as follows, weighing copper nitrate trihydrate 3.0g, zinc nitrate hexahydrate 7.3 and zirconyl nitrate 15.0g, co-dissolving in 200 ml of water, and adjusting ph=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the nitrogen flow rate is 30 ml/min) to obtain the catalyst of 10wt% Cu-10wt% Sn-80wt% ZrO ₂. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 6

10Wt% Cu-10wt% SrO-80wt% Y ₂O₃ was prepared by co-precipitation. The specific operation was as follows, weighing copper nitrate trihydrate 3.0g, yttrium nitrate hexahydrate 54g and strontium nitrate 4.1g, dissolving in 200 ml of water altogether, and adjusting pH value=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the nitrogen flow rate is 30 ml/min) to obtain 10wt% Cu-10wt% SrO-80wt% Y ₂O₃ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 7

5Wt% Cu-84wt% in ₂O₃-11wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing copper nitrate trihydrate 3.8g, cerium nitrate hexahydrate 5.5g and indium nitrate hydrate 36.3g, dissolving in 200 ml of water altogether, and adjusting pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ h (nitrogen flow rate is 30 ml/min) to obtain 5wt% Cu-84wt% in ₂O₃-11wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 8

20Wt% Cu-71wt% in ₂O₃-9wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, 15.2g of copper nitrate trihydrate, 4.5g of cerium nitrate hexahydrate and 30.7g of indium nitrate hydrate were weighed and dissolved in 200 ml of water, and the pH value was adjusted to=10 with an aqueous solution of NaOH (3 mol/L). Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) and obtaining 20wt percent Cu-71wt percent in ₂O₃-9wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 9

10Wt% Cu-80wt% in ₂O₃-10wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 5.0g of cerium nitrate hexahydrate and 34.6g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) and obtaining 10wt percent Cu-80wt percent in ₂O₃-10wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 240℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 10

10Wt% Cu-80wt% in ₂O₃-10wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 5.0g of cerium nitrate hexahydrate and 34.6g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) and obtaining 10wt percent Cu-80wt percent in ₂O₃-10wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 220℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 11

10Wt% Cu-80wt% in ₂O₃-10wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 5.0g of cerium nitrate hexahydrate and 34.6g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) and obtaining 10wt percent Cu-80wt percent in ₂O₃-10wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 10cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 220℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 12

10Wt% Cu-80wt% in ₂O₃-10wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 5.0g of cerium nitrate hexahydrate and 34.6g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) and obtaining 10wt percent Cu-80wt percent in ₂O₃-10wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 20cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 220℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 13

10Wt% Cu to 45wt% in ₂O₃-45wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 22.5g of cerium nitrate hexahydrate and 19.5g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) to obtain 10wt% Cu-45wt% in ₂O₃-45wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 10cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 220℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 14

10Wt% Cu-70wt% in ₂O₃-20wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 10.0g of cerium nitrate hexahydrate and 30.3g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) to obtain 10wt% Cu-70wt% in ₂O₃-20wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 10cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 220℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 15

10Wt% Cu-80wt% in ₂O₃-10wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 5.0g of cerium nitrate hexahydrate and 34.6g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) and obtaining 10wt percent Cu-80wt percent in ₂O₃-10wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 10cm bed, wherein the raw material is 10% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 220℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 16

10Wt% Cu-80wt% in ₂O₃-10wt％CeO₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 5.0g of cerium nitrate hexahydrate and 34.6g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) and obtaining 10wt percent Cu-80wt percent in ₂O₃-10wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 10cm bed layer, wherein the raw material is absolute ethyl alcohol, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 220℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 17

The catalyst used in example 2 was collected, calcined in a muffle furnace at 500 ℃ for 4h, reduced with hydrogen at 300 ℃ for 1h, filled into a reaction tube, and packed with a 15cm bed, the raw material was 5% ethanol aqueous solution, and the mass space velocity was 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 18

The catalyst used in example 17 was collected, calcined in a muffle furnace at 500℃for 4h, reduced with hydrogen at 300℃for 1h, filled into a reaction tube, and packed with a 15cm bed, the starting material was 5% aqueous ethanol solution, and the mass space velocity was 1.5h ^-1. The reaction was carried out at 230℃and after 8 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 19

The catalyst used in example 18 was collected, calcined in a muffle furnace at 500℃for 4h, reduced with hydrogen at 300℃for 1h, filled into a reaction tube, and packed with a 15cm bed, the starting material was 5% aqueous ethanol solution, and the mass space velocity was 1.5h ^-1. The reaction was carried out at 230℃and after 10 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Example 20

The catalyst used in example 19 was collected, calcined in a muffle furnace at 500℃for 4 hours, reduced with hydrogen at 300℃for 1 hour, filled into a reaction tube, and packed with a 15cm bed, the starting material was a 5% aqueous ethanol solution, and the mass space velocity was 1.5h ^-1. The reaction was carried out at 230℃and after 18 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Comparative example 1

10Wt% Cu-90wt% in ₂O₃ was prepared by co-precipitation. The specific procedure was as follows, weighing 7.6g of copper nitrate trihydrate and 38.9g of indium nitrate hydrate, co-dissolving in 200 ml of water, and adjusting the pH value to=10 with aqueous NaOH (3 mol/L). Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) to obtain 10wt% Cu-90wt% in ₂O₃ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a15 cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Comparative example 2

The 10wt% Cu-90wt% CeO ₂ was prepared by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 45.0g of cerium nitrate hexahydrate co-dissolved in 200 ml of water, and adjusting the pH value to be=10 with an aqueous solution of NaOH (3 mol/L). Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) to obtain the 10wt% Cu-90wt% CeO ₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Comparative example 3

The preparation of 10wt% Cu-10wt% in ₂O₃-80wt％CeO₂ was performed by co-precipitation. The specific operation was as follows, weighing 7.6g of copper nitrate trihydrate, 40.0g of cerium nitrate hexahydrate and 4.3g of indium nitrate hydrate, dissolving in 200 ml of water altogether, and adjusting the pH value to be=10 with NaOH (3 mol/L) aqueous solution. Aging and stirring for 2h in an oil bath at 80 ℃, filtering and washing to be neutral. Drying at 80 ℃ overnight, roasting at 500 ℃ CN ₂ for 3 hours (the flow rate of nitrogen is 30 ml/min) to obtain the 10wt% Cu-10wt% in ₂O₃-80wt％CeO₂ catalyst. And (3) filling the 14-25 mesh catalyst into a reaction tube, filling a 15cm bed, wherein the raw material is 5% ethanol water solution, and the mass space velocity is 1.5h ^-1. The reaction was carried out at 230℃and after 2 hours the reaction was analyzed by sample chromatography, and the conversion of ethanol and the selectivity of ethyl acetate were shown in Table 1.

Table 1. Reaction results of alcohol dehydrocondensation to ethyl acetate catalyzed by copper-based acid-base bifunctional catalyst

The result shows that the composition and the content of each component of the heterogeneous copper-based acid-base bifunctional catalyst are key factors influencing the reaction effect. Suitable levels of Cu sites and acid-base sites are critical to achieving high selectivity catalysis, and the absence of acidic sites or basic sites or improper ratios will cause a mismatch in reaction rates, resulting in a significant decrease in ethyl acetate selectivity of the target product. In addition, the reaction temperature, space velocity and other conditions also affect the reaction effect.

Claims

1. A method for preparing ethyl acetate by dehydrogenation condensation of ethanol, characterized in that:

The process of preparing ethyl acetate by dehydrogenation condensation of ethanol is as follows: using ethanol as a raw material, reacting in a fixed bed reactor at a reaction temperature of 220-350°C;

The heterogeneous copper-based acid-base bifunctional catalyst is composed of active Cu and acid-base metal oxides.

The copper-based acid-base bifunctional catalyst, wherein the acidic metal oxide is one, two or more of yttrium oxide, ytterbium oxide, indium oxide, tungsten oxide, scandium oxide, tantalum oxide, niobium oxide, gallium oxide, and tin oxide;

The basic oxide is one, two or more of cerium oxide, lanthanum oxide, praseodymium oxide, magnesium oxide and strontium oxide.

The copper-based acid-base bifunctional catalyst, wherein the active metal Cu content is 5% to 10% by weight;

The mass ratio of acidic oxide to basic oxide is 1:1~10:1.

2. The method according to claim 1, characterized in that the mass ratio of the acidic oxide to the basic oxide is 4:1 to 8:1.

3. The method according to claim 1, characterized in that:

The catalyst bed thickness is 5 cm to 30 cm, the reaction is at normal pressure, and the feed mass space velocity of ethanol is 0.5 to 3.5 h ^-1 .

4. The method according to claim 1 or 3, characterized in that:

The reaction conditions are as follows: the catalyst bed thickness in the reaction tube is 10 cm to 25 cm, and the mass space velocity of the ethanol feed is 1.0 to 2.0 h ^-1 .

5. The method according to claim 1 or 3, characterized in that:

The ethanol is anhydrous ethanol or an ethanol aqueous solution, and the water content is 1.0% to 10% by weight.

6. The method according to claim 1, characterized in that:

The reaction temperature of the ethanol dehydrogenation condensation to produce ethyl acetate is 220-260°C.

7. The method according to claim 1, characterized in that the multiphase copper-based acid-base bifunctional catalyst is prepared by coprecipitation of soluble salts corresponding to Cu, acidic oxides and alkaline oxides in a solution.