A method for preparing high-purity aluminum alkoxide
By directly reacting metal aluminum with alcohol and combining with alumina catalyst supported by aminoacetic acid, the problems of harsh reaction conditions, too fast reaction rates and safety hazards in the existing process are solved, and efficient and safe large-scale industrial production is achieved to obtain high-purity alkoxy aluminum.
Patent Information
- Application Number
- CN202411986467.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-01
AI Technical Summary
The existing organic aluminum alcohol salt hydrolysis process has problems such as harsh reaction conditions, too fast reaction rates, high safety risks and the use of heavy metal catalysts, making it difficult to achieve efficient and safe large-scale industrial production.
The reaction rate is controlled through a multi-step reaction process to avoid inclusion of small particles of aluminum, and the preparation of high-purity alkoxy aluminum is achieved.
The preparation of organic alkoxy aluminum with green mercury-free, simple process and controllable reaction speed is realized, which improves yield and purity, avoids inclusions of small particles of aluminum, and ensures the safety and environmental protection of production.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of alkoxy aluminum preparation methods, and in particular to a method for preparing high-purity alkoxy aluminum. Background Art
[0002] The preparation methods of alumina mainly include the thermal decomposition method of inorganic aluminum salts, the hydrolysis method of high-purity aluminum, the hydrolysis method of organic alcohol salts and the modified Bayer process. The thermal decomposition method of inorganic aluminum salts has strict restrictions on reaction conditions, and the product needs to be recrystallized and purified many times. The modified Bayer process is not suitable for large-scale industrial production due to its complex process. The hydrolysis method of organic alcohol aluminum salts does not produce harmful gases, is pollution-free, and organic alcohols can be recycled, which is expected to achieve large-scale continuous industrial production of high-performance, high-purity alumina.
[0003] At present, the process of hydrolysis of organic alcohol aluminum salt has problems such as harsh reaction conditions, too fast reaction rate, safety hazards caused by the release of hydrogen in the reaction, and the need to use HgCl2 heavy metal catalyst when preparing organic alcohol aluminum salt. In response to the problem of heavy metal catalyst, some researchers proposed to use aluminum chloride as a catalyst, activate the metal before the reaction, remove the oxide film on the aluminum surface, and accelerate the reaction rate of aluminum and organic alcohol. This process avoids the use of heavy metal catalysts, but there are problems such as too fast reaction rate and the inability to effectively control the reaction process, which poses serious safety hazards in industrial scale-up production. In order to control the reaction rate, some processes use aluminum ingots for reaction. This process is prone to produce micron-level and nano-level small particles of aluminum. These small particles of aluminum are mixed in the product mixed gas and cannot be removed, which reduces the yield and affects the color of the product. Summary of the invention
[0004] In order to overcome the above problems, the present invention breaks through the constraints of traditional processes and develops a green, mercury-free, simple, and reaction-speed controllable organic alkoxy aluminum preparation process, thereby realizing low-cost, pollution-free, industrial large-scale production of aluminum isopropoxide.
[0005] The technical solution of the present invention is a method for preparing alkoxy aluminum, which comprises the following steps: 1) The organic alcohol vapor is introduced into a first reaction device containing metallic aluminum and reacted at 135-150 °C.
[0006] 2) The product of step 1 and the organic alcohol mixture are introduced into a second reaction device containing a catalyst and reacted at 900-1300 Pa and 135-150 °C.
[0007] 3) The unreacted organic alcohol in step 2 is circulated into the first reaction device, and the product alkoxyaluminum is cooled to below 110° C. to obtain a solid product.
[0008] The catalyst comprises alumina and aminoacetic acid supported on the alumina, and the loading amount of the aminoacetic acid on the alumina is 0.1% to 5%.
[0009] The organic alcohol is selected from one of C3-C4 organic alcohols.
[0010] Some specific preparation methods of alkoxyaluminum, the loading amount of aminoacetic acid on alumina is 0.5%~3%.
[0011] Some specific preparation methods of alkoxy aluminum, the preparation method of the catalyst is: adding aluminum oxide to an aqueous solution of aminoacetic acid with a mass concentration of 5-10% and immersing it at room temperature for 1-5 hours, and then filtering, drying and calcining in sequence to obtain the catalyst; the drying temperature is 60-120°C, and the calcination temperature is 160-200°C.
[0012] Specifically, the alumina is spherical or strip-shaped β-alumina.
[0013] Specifically, the specific surface area of the alumina is 200-250 m 2 / g, pore volume is 0.5~0.6 cm 3 / g, pore size is 10~12 nm, particle size is 1.8~2.0 mm, strength is greater than or equal to 40 N, and purity is not less than 99%.
[0014] In some specific preparation methods of aluminum alkoxide, the aluminum solid is an aluminum block or an aluminum ingot.
[0015] The volume of the aluminum solid is not less than 0.15 cm 3 The preferred volume of aluminum solid is 0.15 ~50 cm 3 .
[0016] More preferably, the volume of the aluminum solid is 0.18 to 25 cm 3 More preferably, the volume of the aluminum solid is 0.18 to 10 cm 3 .
[0017] In some specific methods for preparing aluminum alkoxides, the reaction endpoint of step 1 is when no aluminum solid is visible to the naked eye.
[0018] Some specific preparation methods of alkoxy aluminum include a drying time of 1 to 10 h and a calcination time of 3 to 8 h.
[0019] In some specific methods for preparing alkoxyaluminum, the organic alcohol is selected from one of propanol and isopropanol.
[0020] In some specific methods for preparing alkoxyaluminum, the organic alcohol is isopropanol.
[0021] In some specific methods for preparing alkoxyaluminum, the reaction time of step 2 is 0.5 to 10 h.
[0022] In some specific preparation methods of aluminum alkoxide, the aluminum alkoxide obtained in step 2 can be used directly. If an aluminum alkoxide product with ultra-high purity is required, it can be further purified by distillation.
[0023] The alkoxy aluminum is prepared by the preparation method described above.
[0024] Beneficial effects of the present invention: The present invention provides a method for preparing aluminum alkoxide, which prepares aluminum alkoxide by direct reaction of metallic aluminum and alcohol, and can avoid the safety problems caused by the use of mercury salt catalysts and excessive reaction speed. In addition, the aluminum oxide catalyst loaded with aminoacetic acid can process unreacted aluminum particles of micrometer level, improve the reaction conversion rate, avoid small aluminum particles being mixed in the product aluminum alkoxide product to affect the product color, and at the same time improve the purity of the product aluminum alkoxide, so as to achieve green, efficient and controllable synthesis of pure organic aluminum. The present invention breaks through the constraints of traditional processes, develops a green, mercury-free, simple process preparation process for organic aluminum alkoxide, and realizes low-cost and pollution-free industrial large-scale production of aluminum isopropoxide. DETAILED DESCRIPTION
[0025] Example 1: Preparation of Catalyst I Alumina was added to a 5% aminoacetic acid aqueous solution at room temperature and immersed for 5 h, filtered, and the solid was dried at 80 °C for 8 h, and then calcined at 180 °C for 5 h to obtain catalyst I.
[0026] The alumina is spherical β-alumina with a diameter of 1.9 mm and a purity greater than 99%, and a specific surface area of 220 m 2 / g, pore volume is 0.55 cm 3 / g, pore size is 11 nm, and strength is 40 N.
[0027] Example 2: Preparation of Catalyst II Alumina was added to an aqueous solution of aminoacetic acid with a mass concentration of 8% and immersed at room temperature for 3 h. The solution was filtered and the solid was dried at 100 °C for 5 h. The solid was then calcined at 190 °C for 4 h to obtain catalyst II.
[0028] The alumina is spherical β-alumina with a diameter of 2 mm and a purity greater than 99%, and a specific surface area of 200 m 2 / g, pore volume is 0.58 cm 3 / g, pore size is 12 nm, and strength is 40 N.
[0029] Example 3: Preparation of Catalyst III Alumina was added to an aqueous solution of aminoacetic acid with a mass concentration of 10% and immersed at room temperature for 2 h. The solution was filtered and the solid was dried at 120°C for 3 h. The solid was then calcined at 200°C for 2 h to obtain catalyst II.
[0030] Alumina is spherical β-alumina with a diameter of 1.8 mm and a purity greater than 99%, and a specific surface area of 240 m 2 / g, pore volume is 0.50 cm 3 / g, pore size is 10 nm, and strength is 40 N.
[0031] Example 4: Preparation of aluminum isopropoxide 500 g of a cylindrical aluminum column with a purity of 99.9%, a diameter of 0.5 cm and a length of 1 cm was added to the first reaction device, isopropanol vapor was circulated into the reaction device, and the reaction was carried out at 145°C. The obtained mixture of aluminum isopropoxide and isopropanol was passed into a second reaction device filled with catalyst I and reacted at 145°C and 1000 Pa for 2 h. The obtained mixture was cooled to 100°C, the solid product aluminum isopropoxide was collected, and the isopropanol was circulated into the first reaction device.
[0032] Example 5: Preparation of aluminum isopropoxide 500 g of a cylindrical aluminum column with a purity of 99.9%, a diameter of 0.5 cm and a length of 1 cm was added to the first reaction device, isopropanol vapor was circulated into the reaction device, and the reaction was carried out at 140°C. The obtained mixture of aluminum isopropoxide and isopropanol was passed into a second reaction device filled with catalyst I and reacted at 140°C and 900 Pa for 2 h. The obtained mixture was cooled to 100°C, the solid product aluminum isopropoxide was collected, and the isopropanol was circulated into the first reaction device.
[0033] Example 6: Preparation of aluminum isopropoxide 500 g of a cylindrical aluminum column with a purity of 99.9%, a diameter of 0.5 cm and a length of 1 cm was added to the first reaction device, isopropanol vapor was circulated into the reaction device, and the reaction was carried out at 145°C. The obtained mixture of aluminum isopropoxide and isopropanol was passed into a second reaction device filled with catalyst II and reacted at 145°C and 1000 Pa for 2 h. The obtained mixture was cooled to 100°C, the solid product aluminum isopropoxide was collected, and the isopropanol was circulated into the first reaction device.
[0034] Example 7: Preparation of aluminum isopropoxide 500 g of a cylindrical aluminum column with a purity of 99.9%, a diameter of 0.5 cm and a length of 1 cm was added to the first reaction device, isopropanol vapor was circulated into the reaction device, and the reaction was carried out at 145°C. The obtained mixture of aluminum isopropoxide and isopropanol was passed into a second reaction device filled with catalyst III and reacted at 145°C and 1000 Pa for 2 h. The obtained mixture was cooled to 100°C, the solid product aluminum isopropoxide was collected, and the isopropanol was circulated into the first reaction device.
[0035] Example 8: Preparation of aluminum isopropoxide 500 g of a cylindrical aluminum column with a purity of 99.9%, a diameter of 0.5 cm and a length of 1 cm was added to the first reaction device, isopropanol vapor was circulated into the reaction device, and the reaction was carried out at 145°C. The obtained mixture of aluminum isopropoxide and isopropanol was passed into a second reaction device filled with catalyst I and reacted at 140°C and 900 Pa for 1 h. The obtained mixture was cooled to 100°C, the solid product aluminum isopropoxide was collected, and the isopropanol was circulated into the first reaction device.
[0036] Example 9: Preparation of aluminum isopropoxide 500 g of a cylindrical aluminum column with a purity of 99.9%, a diameter of 0.5 cm and a length of 1 cm was added to the first reaction device, isopropanol vapor was circulated into the reaction device, and the reaction was carried out at 150°C. The obtained mixture of aluminum isopropoxide and isopropanol was passed into a second reaction device filled with catalyst I and reacted at 145°C and 1000 Pa for 1 h. The obtained mixture was cooled to 100°C, the solid product aluminum isopropoxide was collected, and the isopropanol was circulated into the first reaction device.
[0037] Example 10: Preparation of aluminum isopropoxide 500 g of a cylindrical aluminum column with a purity of 99.9%, a diameter of 0.5 cm and a length of 1 cm was added to the first reaction device, isopropanol vapor was circulated into the reaction device, and the reaction was carried out at 145°C. The obtained mixture of aluminum isopropoxide and isopropanol was passed into a second reaction device filled with catalyst I and reacted at 140°C and 900 Pa for 5 h. The obtained mixture was cooled to 100°C, the solid product aluminum isopropoxide was collected, and the isopropanol was circulated into the first reaction device.
[0038] Comparative Example 1: Preparation of aluminum isopropoxide Add 500 g of a cylindrical aluminum column with a purity of 99.9%, a diameter of 0.5 cm and a length of 1 cm into the first reaction device, add 1.5 L of isopropanol, mix well, add 0.3 g of aluminum trichloride, stir at room temperature for 10 min, heat to 120 °C under argon protection, react until the aluminum block disappears, cool to obtain aluminum isopropoxide, filter the product, and purify by distillation to obtain aluminum isopropoxide.
[0039] Comparative Example 2: Preparation of aluminum isopropoxide 500 g of a cylindrical aluminum column with a purity of 99.9%, a diameter of 0.5 cm and a length of 1 cm was added to the first reaction device, isopropanol vapor was circulated into the reaction device, and the reaction was carried out at 145°C. The obtained mixture of aluminum isopropoxide and isopropanol was passed into a second reaction device filled with alumina and reacted at 145°C and 1000 Pa for 2 h. The obtained mixture was cooled, the solid product aluminum isopropoxide was collected, and the isopropanol was circulated into the first reaction device.
[0040] Test Example: The yield, product purity and chromaticity data of aluminum isopropoxide prepared in Examples 1-7 and Comparative Examples 1-2 are shown in Table 1.
[0041] Table 1 Yield data of aluminum isopropoxide
[0042] As shown in the data in Table 1, the method of the present invention can effectively improve the yield of aluminum isopropoxide, obtain an aluminum isopropoxide product with higher purity, avoid the use of highly toxic mercuric chloride catalyst, and make the reaction safe and controllable.
Claims
1. A method for preparing an alkoxy aluminum, characterized in that: Use the following steps: 1) circulating the organic alcohol vapor into the first reaction device filled with metal aluminum to react at 135-150°C; 2) introducing the product of step 1 and the organic alcohol mixture into a second reaction device containing a catalyst, and reacting at 900-1300 Pa and 135-150 °C; 3) circulating the unreacted organic alcohol in step 2 into the first reaction device, and cooling the product alkoxyaluminum to obtain a solid product; The catalyst comprises alumina and aminoacetic acid loaded on the alumina, wherein the loading amount of aminoacetic acid on the alumina is 0.1% to 5%; The organic alcohol is selected from one of C3-C4 organic alcohols.
2. The method for preparing aluminum alkoxide according to claim 1, characterized in that: The loading amount of aminoacetic acid on alumina is 0.5%~3%.
3. The method for preparing aluminum alkoxide according to claim 2, characterized in that: The alumina is spherical or strip-shaped β-alumina with a specific surface area of 200-250 m 2 / g, pore volume is 0.5~0.6 cm 3 / g, pore size is 10~12 nm, particle size is 1.8~2.0 mm, strength is greater than or equal to 40 N, and purity is not less than 99%.
4. The method for preparing aluminum alkoxide according to claim 3, characterized in that: The preparation method of the catalyst is as follows: adding aluminum oxide to an aqueous solution of aminoacetic acid with a mass concentration of 5-10% and immersing it at room temperature for 1-5 hours, and then filtering, drying and calcining in sequence to obtain the catalyst; The drying temperature is 60~120 ℃, and the calcination temperature is 160~200 ℃.
5. The method for preparing aluminum alkoxide according to claim 4, characterized in that: The drying time is 1~10 h, and the roasting time is 3~8 h.
6. The method for preparing an aluminum alkoxide according to any one of claims 1 to 5, characterized in that: The volume of the aluminum solid is not less than 0.15 cm 3 .
7. The method for preparing aluminum alkoxide according to any one of claims 1 to 5, characterized in that: The organic alcohol is selected from one of propanol and isopropanol.
8. The method for preparing aluminum alkoxide according to claim 7, characterized in that: The organic alcohol is isopropanol.
9. The method for preparing aluminum alkoxide according to claim 8, characterized in that: The reaction time of step 2 is 0.5~10 h.
10. Alkoxyaluminum prepared according to the preparation method according to any one of claims 1 to 5.