Method for preparing sodium ethoxide from sodium acetate
By constructing an organometallic composite active site catalyst through multi-stage modification technology, the problems of high safety risks, high costs, and low selectivity in the preparation of sodium ethoxide were solved, achieving low-cost and high-efficiency preparation of sodium ethoxide.
Patent Information
- Application Number
- CN202511361355.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-23
- Publication Date
- 2025-12-23
AI Technical Summary
Existing methods for preparing sodium ethoxide suffer from high safety risks, high costs, harsh reaction conditions, low selectivity, and serious waste of resources.
A multi-stage modification technique was used to construct an organometallic composite active site catalyst. By modifying the alumina support with ammonium dihydrogen phosphate and citric acid, a coordination bond between rare earth cerium and mercaptoacetic acid was formed. Combined with the in-situ reaction of diethylzinc, a Zn-O-Al bonded active center was constructed, which enhanced the activation ability and stability of the catalyst.
This method enables efficient preparation of sodium ethoxide under simple, low-cost, and mild conditions, improving product selectivity and catalyst stability while reducing byproduct formation and resource waste.
Abstract
Description
Technical Field
[0001] This invention relates to the field of organic compound preparation technology, and more specifically, to a method for preparing sodium ethoxide using sodium acetate. Background Technology
[0002] Sodium ethoxide, due to its extremely high chemical reactivity, is a commonly used intermediate and catalyst in chemical reactions. It can be used in organic reactions involving ring opening, condensation, and rearrangement, and is therefore frequently used in the synthesis of chemical products, especially in the production of fine chemicals. Currently in industry, sodium ethoxide is mainly used in the synthesis of pharmaceutical and pesticide products, such as phenobarbital, phenylbutazone, primidone, methyldopa, and ethylamine pyridine. It can also be used as an analytical reagent.
[0003] Currently, traditional methods for preparing sodium ethoxide mainly include the sodium metal method and the sodium alkoxide exchange method. The sodium metal method directly reacts sodium metal with ethanol to produce sodium ethoxide. Although the reaction principle is simple, sodium metal is chemically reactive, posing high safety risks during storage and transportation. Furthermore, the reaction easily generates byproducts, affecting product purity. Additionally, the high cost of sodium metal hinders large-scale industrial production. The sodium alkoxide exchange method typically involves exchanging other sodium alkoxides with ethanol. However, this method often requires harsh reaction conditions, has low reaction selectivity, easily generates various byproducts, increasing the difficulty of subsequent separation and purification, and has low raw material utilization, resulting in resource waste and increased production costs. Conversion routes using carboxylates as raw materials have attracted attention. Attempts to prepare sodium ethoxide using solid-phase pyrolysis of sodium acetate have been reported in existing technologies, but these reactions typically require high temperature and high pressure conditions, resulting in long reaction times and high raw material costs. Therefore, this invention provides a method for preparing sodium ethoxide using sodium acetate to solve the aforementioned technical problems. Summary of the Invention
[0004] To address the aforementioned problems, this invention provides a method for preparing sodium ethoxide using sodium acetate. This method is characterized by its simple operation, low industrial cost, mild reaction conditions, environmental friendliness, and high product selectivity, effectively improving reaction efficiency and purity.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] A method for preparing sodium ethoxide using sodium acetate includes the following steps: S1, γ-Al2O3 is placed in a muffle furnace and pretreated by calcination at 470-530℃ for 2-4 hours, then impregnated in deionized water containing ammonium dihydrogen phosphate and citric acid, stirred continuously at room temperature for 4-6 hours, vacuum dried, and then placed in a muffle furnace and calcined at 470-530℃ for 4-6 hours to obtain an alumina support;
[0007] S2. Dissolve cerium ammonium nitrate and mercaptoacetic acid in deionized water, add this solution to the alumina support, keep at room temperature for 2-3 hours and then vacuum dry to obtain the precursor.
[0008] S3. The precursor is impregnated in a 15-20wt% diethylzinc ethanol solution and thoroughly mixed with the precursor. After standing at room temperature for 2-3 hours, the mixture is vacuum dried. Then, the material is placed in a tube furnace and calcined in nitrogen at 400-450℃ for 3-4 hours to obtain the catalyst.
[0009] S4. Fill the fixed-bed reactor with catalyst and sodium acetate to form a 4-6 cm high stacked bed. Introduce high-purity nitrogen into the reactor system to completely replace the air in the system. After the replacement is completed, switch to hydrogen and heat to 170-180℃ at a rate of 2-3℃ / min for 6-8 hours.
[0010] After the reaction in step S5 and S4 is completed and naturally cooled to room temperature, anhydrous ethanol is added, and the reaction solution is transferred to another reactor. The system is gradually heated to 80-85℃, and sodium ethoxide is obtained by distillation.
[0011] Preferably, in step S1, each component comprises 20-25 parts by weight of γ-Al2O3, 1.5-2.2 parts by weight of ammonium dihydrogen phosphate, 0.25-0.35 parts by weight of citric acid, and 60-65 parts by weight of deionized water.
[0012] Preferably, in step S2, each component comprises, by weight, 0.85-0.95 parts of cerium ammonium nitrate, 0.22-0.28 parts of mercaptoacetic acid, 24-26 parts of deionized water, and 9-12 parts of alumina carrier.
[0013] Preferably, in step S3, each component comprises 9-12 parts by weight of the precursor and 25-30 parts by weight of the diethylzinc ethanol solution.
[0014] Preferably, the mass ratio of catalyst to sodium acetate in step S4 is (0.6-0.8):(12-15).
[0015] Preferably, in step S1, the pretreatment roasting temperature is 470-530℃ and the roasting time is 2-4h, and the re-roasting temperature after vacuum drying is 470-530℃ and the roasting time is 4-6h.
[0016] Preferably, in step S3, the room temperature standing impregnation time is 2-3 hours, the nitrogen roasting temperature in the tubular furnace is 400-450℃, and the roasting time is 3-4 hours.
[0017] Preferably, in step S4, the height of the bed is 4-6 cm, the heating rate in the hydrogen atmosphere is 2-3 °C / min, the reaction temperature is 170-180 °C, and the reaction time is 6-8 h.
[0018] Compared with the prior art, the beneficial effects of the present invention are:
[0019] This invention constructs a highly efficient organometallic composite active site catalyst through a multi-stage modification technique. The alumina support is surface-modified using the synergistic effect of ammonium dihydrogen phosphate and citric acid, enhancing the uniformity of acidic site distribution. Subsequently, a stable organometallic precursor structure is formed through coordination bonding between rare earth cerium and thiol groups. Finally, a Zn-O-Al bonded active center is constructed on the support surface using an in-situ reaction of diethylzinc, enhancing the hydrogenation reaction activity and product selectivity. Furthermore, this multi-stage synergistic effect significantly enhances the catalyst surface's activation capacity for acetyl groups in sodium acetate molecules, effectively lowering the decarboxylation reaction energy barrier, while simultaneously improving the catalyst's resistance to coking and thermomechanical stability, solving the efficiency degradation problem caused by sintering of active components and surface acidity imbalance in traditional catalysts. The entire preparation process is simple to operate, uses low-cost raw materials, operates under relatively mild conditions, and has a short reaction time, while generating no large amounts of harmful pollutants during the reaction. Detailed Implementation
[0020] 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.
[0021] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used, unless otherwise specified, were all purchased from conventional biochemical reagent stores. All quantitative experiments in the following examples were performed in triplicate, and the data are the average of the three replicates or the average ± standard deviation.
[0022] 5A molecular sieve, purchased from Shanghai Myriel Biochemical Technology Co., Ltd., CAS number Particle size 1-3mm;
[0023] Example 1
[0024] A method for preparing sodium ethoxide using sodium acetate includes the following steps:
[0025] S1. Place 20 parts of γ-Al2O3 in a muffle furnace and pre-treat it by calcining at 470℃ for 4 hours. Then, immerse it in 60 parts of deionized water containing 1.5 parts of ammonium dihydrogen phosphate and 0.25 parts of citric acid. Stir continuously at 350 rpm for 6 hours at room temperature and then vacuum dry it. Finally, place it in a muffle furnace and calcine at 470℃ for 6 hours to obtain an alumina support.
[0026] S2. Dissolve 0.85 parts of cerium ammonium nitrate and 0.22 parts of mercaptoacetic acid in 24 parts of deionized water. Add this solution to 9 parts of alumina support, keep at room temperature for 3 hours and then vacuum dry to obtain the precursor.
[0027] S3. Nine parts of precursor were impregnated in 25 parts of 15wt% diethylzinc ethanol solution, and the mixture was thoroughly mixed with the precursor. After standing at room temperature for 3 hours, the mixture was vacuum dried. Then, the material was placed in a tube furnace and calcined in nitrogen at 400℃ for 4 hours to obtain the catalyst.
[0028] S4. In a fixed-bed reactor, a catalyst and sodium acetate with a mass ratio of 0.6:12 are packed to form a 4cm high stacked bed. High-purity nitrogen is introduced into the reactor system to completely replace the air in the system. After the replacement is completed, hydrogen is introduced and the temperature is increased to 170℃ at a rate of 2℃ / min for 8 hours.
[0029] After the reaction in step S5 and S4 is completed and naturally cooled to room temperature, anhydrous ethanol is added, and the reaction solution is transferred to another reactor. The system is gradually heated to 80°C, and sodium ethoxide is obtained by distillation.
[0030] Example 2
[0031] A method for preparing sodium ethoxide using sodium acetate includes the following steps:
[0032] S1. 23 parts of γ-Al2O3 were placed in a muffle furnace and calcined at 500℃ for 3.5h for pretreatment. Then, they were impregnated in 63 parts of deionized water containing 1.9 parts of ammonium dihydrogen phosphate and 0.3 parts of citric acid. After stirring continuously at 360rpm for 5.6h at room temperature, they were vacuum dried and then calcined in a muffle furnace at 500℃ for 5h to obtain an alumina support.
[0033] S2. Dissolve 0.9 parts of cerium ammonium nitrate and 0.25 parts of mercaptoacetic acid in 25 parts of deionized water. Add this solution to 10 parts of alumina support, keep at room temperature for 2.8 hours, and then vacuum dry to obtain the precursor.
[0034] S3. 10 parts of precursor were impregnated in 28 parts of 16wt% diethylzinc ethanol solution and thoroughly mixed with the precursor. After standing at room temperature for 2.6 h, the mixture was vacuum dried. The material was then placed in a tube furnace and calcined in nitrogen at 420℃ for 3.8 h to obtain the catalyst.
[0035] S4. In a fixed-bed reactor, a catalyst and sodium acetate with a mass ratio of 0.7:13 are packed to form a 5cm high stacked bed. High-purity nitrogen is introduced into the reactor system to completely replace the air in the system. After the replacement is completed, hydrogen is introduced and the temperature is increased to 173℃ at a rate of 2.3℃ / min for 7.6h.
[0036] After the reaction in step S5 and S4 is completed and naturally cooled to room temperature, anhydrous ethanol is added, and the reaction solution is transferred to another reactor. The system is gradually heated to 83°C, and sodium ethoxide is obtained by distillation.
[0037] Example 3
[0038] A method for preparing sodium ethoxide using sodium acetate includes the following steps:
[0039] S1. Place 25 parts of γ-Al2O3 in a muffle furnace and pre-treat it by calcining at 530℃ for 2 hours. Then, immerse it in 65 parts of deionized water containing 2.2 parts of ammonium dihydrogen phosphate and 0.35 parts of citric acid. Stir continuously at 450 rpm for 4 hours at room temperature and then vacuum dry it. Finally, place it in a muffle furnace and calcine at 530℃ for 4 hours to obtain an alumina support.
[0040] S2. Dissolve 0.95 parts of cerium ammonium nitrate and 0.28 parts of mercaptoacetic acid in 26 parts of deionized water. Add this solution to 12 parts of alumina support, keep at room temperature for 2 hours and then vacuum dry to obtain the precursor.
[0041] S3. 12 parts of precursor were impregnated in 30 parts of 20wt% diethylzinc ethanol solution, and the mixture was thoroughly mixed with the precursor. After standing at room temperature for 2 hours, the mixture was vacuum dried. The material was then placed in a tube furnace and calcined in nitrogen at 450℃ for 3 hours to obtain the catalyst.
[0042] S4. In a fixed-bed reactor, a catalyst and sodium acetate with a mass ratio of 0.8:15 are packed to form a 6cm high stacked bed. High-purity nitrogen is introduced into the reactor system to completely replace the air in the system. After the replacement is completed, hydrogen is introduced and the temperature is increased to 180℃ at a rate of 3℃ / min for 6h.
[0043] After the reaction in step S5 and S4 is completed and naturally cooled to room temperature, anhydrous ethanol is added, and the reaction solution is transferred to another reactor. The system is gradually heated to 85°C, and sodium ethoxide is obtained by distillation.
[0044] Example 4
[0045] A method for preparing sodium ethoxide using sodium acetate includes the following steps:
[0046] S1. Place 25 parts of γ-Al2O3 in a muffle furnace and pre-treat it by calcining at 530°C for 3 hours. Then, immerse it in 60 parts of deionized water containing 2.2 parts of ammonium dihydrogen phosphate and 0.35 parts of citric acid. Stir continuously at 450 rpm for 5 hours at room temperature and then vacuum dry it. Finally, place it in a muffle furnace and calcine at 530°C for 5 hours to obtain an alumina support.
[0047] S2. Dissolve 0.95 parts of cerium ammonium nitrate and 0.25 parts of mercaptoacetic acid in 26 parts of deionized water. Add this solution to 10 parts of alumina support, keep at room temperature for 2.5 hours, and then vacuum dry to obtain the precursor.
[0048] S3. 12 parts of precursor were impregnated in 30 parts of 18wt% diethylzinc ethanol solution, and the mixture was thoroughly mixed with the precursor. After standing at room temperature for 2.6 h, the mixture was vacuum dried. The material was then placed in a tube furnace and calcined in nitrogen at 450℃ for 3.2 h to obtain the catalyst.
[0049] S4. In a fixed-bed reactor, a catalyst and sodium acetate with a mass ratio of 0.8:13 are packed to form a 5cm high stacked bed. High-purity nitrogen is introduced into the reactor system to completely replace the air in the system. After the replacement is completed, hydrogen is introduced and the temperature is increased to 180℃ at a rate of 3℃ / min for 8 hours.
[0050] After the reaction in step S5 and S4 is completed and naturally cooled to room temperature, anhydrous ethanol is added, and the reaction solution is transferred to another reactor. The system is gradually heated to 85°C, and sodium ethoxide is obtained by distillation.
[0051] Comparative Example 1
[0052] A method for preparing sodium ethoxide using sodium acetate differs from Example 4 in that the carrier modification treatment is omitted. Specifically, γ-Al₂O₃ that has not been modified with ammonium dihydrogen phosphate and citric acid is used directly for subsequent operations. γ-Al₂O₃ that has not undergone calcination and impregnation treatment in step S1 is directly used for the precursor preparation in step S2, and the remaining operating parameters are exactly the same as in Example 4.
[0053] Comparative Example 2
[0054] A method for preparing sodium ethoxide using sodium acetate differs from Example 4 in that the cerium species loading step is omitted. Specifically, the complexation and impregnation process of cerium ammonium nitrate and mercaptoacetic acid is skipped, and the alumina support obtained in step S1 is directly used for diethylzinc loading in step S3. The remaining operating parameters are exactly the same as in Example 4.
[0055] Comparative Example 3
[0056] A method for preparing sodium ethoxide using sodium acetate differs from Example 4 in that the zinc active site construction step is omitted. Specifically, the precursor obtained in step S2 is used directly as a catalyst in step S4 without diethylzinc impregnation and nitrogen calcination. The remaining operating parameters are exactly the same as in Example 4.
[0057] Comparative Example 4
[0058] A method for preparing sodium ethoxide using sodium acetate differs from Example 4 in that the addition of mercaptoacetic acid is omitted in step S2. Specifically, only cerium ammonium nitrate is dissolved in deionized water to impregnate the carrier. 0.95 parts of cerium ammonium nitrate are weighed and dissolved in 26 parts of deionized water, 10 parts of alumina carrier are added and impregnated for 2.5 hours, and after drying, the defect precursor is obtained. The remaining operating parameters are exactly the same as in Example 4.
[0059] Comparative Example 5
[0060] A method for preparing sodium ethoxide using sodium acetate differs from Example 4 in that an inorganic zinc salt is used instead of an organic zinc source in step S3. Specifically, the diethylzinc ethanol solution is replaced with an aqueous solution of zinc nitrate of equimolar concentration, and the precursor is immersed in the zinc nitrate solution and then treated in the same way. The remaining operating parameters are exactly the same as in Example 4.
[0061] Comparative Example 6
[0062] A method for preparing sodium ethoxide using sodium acetate differs from Example 4 in that the carrier material is changed. Specifically, in steps S1-S3, an equal amount of 5A molecular sieve is used to replace γ-Al2O3, and 25 parts of 5A molecular sieve are directly modified with phosphate / citric acid and then loaded. The remaining operating parameters are exactly the same as in Example 4.
[0063] Performance testing
[0064] The methods for preparing sodium ethoxide from sodium acetate in Examples 1-4 and Comparative Examples 1-6 were tested for performance, and the test results are shown in Table 1 below.
[0065] Table 1
[0066] Test Project Ammonium acetate conversion rate % Sodium ethoxide purity % Catalyst activity retention rate after 5 cycles (%) Example 1 94.35 98.71 90.27. Example 2 95.18 99.02 93.45 Example 3 96.87 99.41 95.16 Example 4 97.24 99.73 96.33 Comparative Example 1 70.83 94.26 62.14 Comparative Example 2 74.65 94.87 70.33 Comparative Example 3 67.92 93.11 58.47 Comparative Example 4 81.57 95.38 75.29 Comparative Example 5 72.41 93.94 65.82 Comparative Example 6 57.26 89.75 48.26
[0067] Examples 1-4 exhibit excellent catalytic efficiency and product quality. Example 4 achieved a sodium acetate conversion of 97.24%, sodium ethoxide purity of 99.73%, and catalyst activity retention of 96.33% after 5 cycles, verifying the synergistic optimization effect of multi-stage modified catalyst and process parameters. This result demonstrates that by progressively optimizing process steps such as the pretreatment parameters of the γ-Al₂O₃ support, the coordination ratio of cerium ammonium nitrate to mercaptoacetic acid, and the impregnation conditions of diethylzinc ethanol solution, a highly efficient and stable catalytic system can be effectively constructed, enhancing the synergistic effect between active components and thus significantly improving reaction conversion, product purity, and catalyst cycle stability.
[0068] The performance of each comparative example was significantly lower than that of the example. The core reason for this was that the absence of key process steps or the replacement of materials disrupted the synergistic effect of the catalytic system. Comparative Example 1, due to the lack of modification of the support with ammonium dihydrogen phosphate and citric acid, resulted in uneven distribution of acidic sites on the support surface, decreased loading of active components, and a significant reduction in conversion rate and stability. Comparative Example 3 lacked the construction of zinc active sites, failing to form effective catalytic centers and exhibiting significantly insufficient catalytic activity. Comparative Example 6, which used 5A molecular sieve instead of γ-Al2O3, suffered from the worst performance due to the mismatch in support pore size, which limited reactant diffusion and activation. Other comparative examples, either due to the absence of cerium species or mercaptoacetic acid, or due to the replacement of the zinc source type, all damaged the structural integrity and stability of the active centers of the catalyst to varying degrees, ultimately leading to a comprehensive decline in conversion rate, purity, and cycle performance.
[0069] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.
Claims
1. A method for preparing sodium ethoxide using sodium acetate, characterized in that, Includes the following steps: S1. Pre-treat γ-Al2O3 in a muffle furnace, then impregnate it in an aqueous solution containing ammonium dihydrogen phosphate and citric acid, and obtain an alumina support by stirring, vacuum drying, and calcination. S2. Dissolve cerium ammonium nitrate and mercaptoacetic acid in deionized water, add this solution to alumina support, and obtain the precursor by impregnation and vacuum drying. S3. The precursor is impregnated in a 15-20wt% diethylzinc ethanol solution, thoroughly mixed, allowed to stand for impregnation, vacuum dried, and then calcined in a tube furnace under nitrogen to obtain the catalyst. S4. In a fixed-bed reactor, a catalyst and sodium acetate are packed to form a stacked bed. High-purity nitrogen is introduced to replace the air in the system. After the replacement is completed, hydrogen is introduced and the temperature is increased to react. After the reaction in step S5 and S4 is completed and naturally cooled to room temperature, anhydrous ethanol is added, and the reaction solution is transferred to another reactor. The system is then heated and distilled to obtain sodium ethoxide.
2. The method for preparing sodium ethoxide using sodium acetate according to claim 1, characterized in that, In step S1, each component consists of 20-25 parts by weight of γ-Al2O3, 1.5-2.2 parts by weight of ammonium dihydrogen phosphate, 0.25-0.35 parts by weight of citric acid, and 60-65 parts by weight of deionized water.
3. The method for preparing sodium ethoxide using sodium acetate according to claim 1, characterized in that, In step S2, each component comprises, by weight, 0.85-0.95 parts cerium ammonium nitrate, 0.22-0.28 parts mercaptoacetic acid, 24-26 parts deionized water, and 9-12 parts alumina carrier.
4. The method for preparing sodium ethoxide using sodium acetate according to claim 1, characterized in that, In step S3, each component consists of 9-12 parts by weight of the precursor and 25-30 parts by weight of the diethylzinc ethanol solution.
5. The method for preparing sodium ethoxide using sodium acetate according to claim 1, characterized in that, In step S4, the mass ratio of catalyst to sodium acetate is (0.6-0.8):(12-15).
6. The method for preparing sodium ethoxide using sodium acetate according to claim 1, characterized in that, In step S1, the pretreatment roasting temperature is 470-530℃ and the roasting time is 2-4h. After vacuum drying, the re-roasting temperature is 470-530℃ and the roasting time is 4-6h.
7. The method for preparing sodium ethoxide using sodium acetate according to claim 1, characterized in that, In step S3, the room temperature standing impregnation time is 2-3 hours, the nitrogen roasting temperature in the tubular furnace is 400-450℃, and the roasting time is 3-4 hours.
8. The method for preparing sodium ethoxide using sodium acetate according to claim 1, characterized in that, In step S4, the height of the bed is 4-6 cm, the heating rate in a hydrogen atmosphere is 2-3 °C / min, the reaction temperature is 170-180 °C, and the reaction time is 6-8 h.