Preparation method of aluminum alkyl
Alkyl aluminum was prepared by reacting alkali metal hydrides with aluminum trihalides in aprotic solvents, which solved the problems of flammable gas use and complex equipment, and achieved efficient and low-cost preparation of alkyl aluminum, improving product yield and purity.
Patent Information
- Application Number
- CN202411294084.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2026-03-17
AI Technical Summary
Existing methods for preparing alkylaluminum require the use of flammable and explosive hydrogen gas, consume a lot of time and materials and equipment, have complex reactions and low product yields, and are difficult to separate aluminum powder from the metal salts produced in the reaction.
Alkali metal hydrides are used as hydrogen sources to react with aluminum trihalides and alkenes in aprotic solvents to form aluminum complexes through coordination with ether reagents. Alkyl aluminum is then separated by heating and/or vacuum treatment, avoiding the use of flammable gases and complex equipment.
The reaction is carried out under normal pressure, which reduces costs, improves efficiency and product yield, simplifies the process, reduces the introduction of impurities, and improves the purity and yield of alkyl aluminum.
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Figure CN121673308A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of alkyl aluminum preparation technology, and in particular to a method for preparing alkyl aluminum. Background Technology
[0002] Alkyl aluminum is an organoaluminum compound formed by the direct combination of an alkyl group and metallic aluminum, with the general formula AlR3 (where R stands for alkyl). Alkyl aluminum exhibits extremely high reactivity and is commonly used as a catalyst and reaction intermediate in organic synthesis. It can catalyze a variety of organic reactions, improving reaction efficiency and yield. In the preparation of polymer materials, it can participate in polymerization reactions, influencing the structure and properties of the polymer. Simultaneously, alkyl aluminum can be used to prepare semiconductor materials, electrode materials, and more. These materials play a crucial role in the manufacture of electronic devices and are of great significance to the development of the electronics industry.
[0003] Currently, the main industrial synthesis methods for alkylaluminum are direct synthesis and metal reduction. Direct synthesis involves reacting metallic aluminum, hydrogen, and olefins under specific temperature and pressure conditions to obtain the corresponding alkylaluminum. The main disadvantages of this method are the requirement for high-pressure conditions (2-30 MPa) and the use of flammable and explosive hydrogen. Furthermore, it requires specialized ball milling equipment to prepare highly activated metallic aluminum, consuming significant time and resources. Metal reduction, on the other hand, involves reacting aluminum powder with haloalkanes under specific temperature and pressure conditions to obtain the corresponding haloalkylaluminum, followed by a reducing metal reaction to yield the alkylaluminum. The main disadvantages of this method are the complexity of the reaction leading to a relatively low product yield, the difficulty in separating the aluminum powder from the metal salt produced in the reaction, and the need for specialized ball milling equipment to prepare highly activated metallic aluminum powder, also requiring significant time and resources. Summary of the Invention
[0004] Based on this, some embodiments of this application provide a method for preparing alkyl aluminum to solve the problems in the related art, such as the need to use flammable and explosive hydrogen, the need to consume a lot of time and materials and equipment, the complexity of the reaction resulting in low product yield, and the difficulty in separating aluminum powder from the metal salt produced by the reaction.
[0005] In a first aspect, a method for preparing alkylaluminum is provided, comprising:
[0006] Alkyl aluminum is prepared by reacting alkali metal hydrides as hydrogen sources with aluminum trihalides and olefins.
[0007] Alkali metal hydrides are compounds formed by alkali metals (such as lithium, sodium, and potassium) and hydrogen. The hydride anions in alkali metal hydrides can act as nucleophiles to attack the aluminum ions in aluminum trihalide molecules. The hydride anions donate a pair of electrons to form a coordinate bond with the aluminum ions, thereby forming aluminum hydride. Aluminum hydride can then undergo an addition reaction with alkenes to prepare alkyl aluminum.
[0008] Among them, aluminum trihalides can be selected from at least one of aluminum trichloride, aluminum trifluoride, aluminum tribromide, and aluminum triiodide.
[0009] Optionally, the alkali metal hydride includes at least one of sodium hydride and potassium hydride.
[0010] Optionally, the alkali metal hydride reacts with aluminum trihalide and olefins in a solvent, including aprotic solvents and ethers, which can coordinate with aluminum trihalide and can be separated from alkylaluminum under heating and / or reduced pressure.
[0011] Aprotic solvents are solvents whose molecules contain no transferable protons. Because aprotic solvent molecules do not contain transferable protons, they do not participate in proton transfer reactions. They are suitable for proton-sensitive reactions, and are especially suitable for dissolving many substances that are difficult to dissolve in protic solvents, such as organometallic compounds.
[0012] By adding ether reagents to aprotic solvents, the solubility of aluminum trihalides in aprotic solvents can be increased because these ether reagents can coordinate with aluminum trihalides to form organometallic compounds. This facilitates the reaction of aluminum trihalides with alkali metal hydrides to form aluminum hydride, and the reaction of aluminum hydride with alkenes to form alkyl aluminum, thereby improving the reaction efficiency. After the formation of alkyl aluminum, the ether reagents can be separated from the alkyl aluminum by heating and / or reducing the pressure, thus yielding alkyl aluminum.
[0013] Among them, the above-mentioned aprotic solvents are selected from C5~C 14 At least one of the alkanes.
[0014] Optionally, the ether reagent is selected from one or more compounds with the general formula R1-O-R2;
[0015] Among them, R1 and R2 are each independently selected from C6~C6. 12 aryl; or,
[0016] R1 is selected from C1~C5 alkyl groups, and R2 is selected from C6~C5 alkyl groups. 12 Aryl group, R1 is bonded to O through an m-th carbon atom, where m is an integer from 1 to 3; or,
[0017] R1 and R2 are each independently selected from C1 to C5 alkyl groups, and at least one of R1 and R2 is bonded to O through an n-order carbon atom, where n is an integer from 2 to 3.
[0018] R1 is bonded to O through m-level carbon atoms, where m is an integer from 1 to 3. This means that R1 can be bonded to O through primary, secondary, or tertiary carbon atoms. When R1 is bonded to O through primary carbon atoms, the carbon atom in R1 bonded to O is directly connected to one carbon atom; when R1 is bonded to O through secondary carbon atoms, the carbon atom in R1 bonded to O is directly connected to two carbon atoms; and when R1 is bonded to O through tertiary carbon atoms, the carbon atom in R1 bonded to O is directly connected to three carbon atoms.
[0019] For example, when R1 is bonded to O through a primary carbon atom, the primary carbon atom is directly connected to a carbon atom. In this case, R1 can be -CH2-CH3, -CH2-CH2-CH3, -CH2-CH2-CH2-CH3, -CH2-CH(CH3)2, -CH2-CH(CH3)-CH2-CH3, -CH2-C(CH3)3, or -CH2-CH2-CH(CH3)2.
[0020] For another example, when R1 is bonded to O through a secondary carbon atom, the secondary carbon atom is directly connected to two carbon atoms. In this case, R1 can be -CH(CH3)2, -CH(CH3)-CH2-CH3, -CH(CH3)-CH2-CH2-CH3 or -CH(CH3)-CH(CH3)2.
[0021] As another example, when R1 is bonded to O through a tertiary carbon atom, the tertiary carbon atom is directly connected to three carbon atoms. In this case, R1 can be -C(CH3)3 or -C(CH2-CH3)(CH3)2.
[0022] Similarly, if at least one of R1 and R2 is bonded to O through an n-level carbon atom, where n is an integer from 2 to 3, it means that R1 can be bonded to O through a secondary or tertiary carbon atom, in which case R2 can be bonded to O through a primary, secondary, or tertiary carbon atom; or, if R2 is bonded to O through a secondary or tertiary carbon atom, in which case R1 can be bonded to O through a primary, secondary, or tertiary carbon atom. The secondary, tertiary, and primary carbon atoms are described above and will not be repeated here.
[0023] These ether reagents have significant steric hindrance. Therefore, compared with the related technologies that use small molecule ethers (such as diethyl ether, tetrahydrofuran, etc.) as solvents to prepare alkylaluminum, where these small molecule ethers are not easy to separate from alkylaluminum, these ether reagents are more easily removed during or after the reaction by heating and / or reducing pressure. This allows the alkylaluminum to be released without affecting its subsequent reactivity, making it easier for alkylaluminum to be used.
[0024] Optionally, the ether reagent is selected from at least one of diisopropyl ether, ethyl isopentyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, tert-butylphenyl ether, and isopropylphenyl ether.
[0025] Optionally, alkali metal hydrides are used as hydrogen sources to react with aluminum trihalides and olefins to prepare alkylaluminum, including:
[0026] The first aluminum complex was prepared by coordinating aluminum ions in aluminum trihalide with an ether reagent; the ligands of the first aluminum complex contained halide ions and an ether reagent.
[0027] A mixed solution of the first aluminum complex and the alkali metal hydride was prepared by dissolving the first aluminum complex and the alkali metal hydride in an aprotic solvent.
[0028] The first aluminum complex and the alkali metal hydride undergo a first reaction to generate a first product; the first product includes a second aluminum complex and / or aluminum hydride, and the ligands of the second aluminum complex contain hydrogen ions and ether reagents.
[0029] The first product and the olefin undergo a second reaction to generate a second product, which includes a third aluminum complex and / or alkyl aluminum, and the ligands of the third aluminum complex include alkyl and ether reagents.
[0030] In cases where the second product includes a third aluminum complex, the preparation method further includes:
[0031] Alkyl aluminum is prepared by heating and / or reducing pressure on the third aluminum complex to detach the ether reagent from the third aluminum complex.
[0032] Optionally, both the first and second reactions are carried out in solution;
[0033] The preparation of alkylaluminum by heating and / or reducing pressure on the third aluminum complex to desorb the ether reagent from the third aluminum complex includes:
[0034] The reaction solution after the second reaction was subjected to vacuum distillation so that the ether solvent was removed from the third aluminum complex and evaporated.
[0035] Vacuum distillation can remove ether solvents from the third aluminum complex and evaporate them, improving efficiency and reducing ether reagent residues.
[0036] Optionally, the vacuum distillation process is carried out at a temperature of 100°C and a pressure of 0.01 MPa to 0.1 MPa.
[0037] Optionally, the temperature of the first reaction is 50℃~100℃, and the time is 0.5 h~12 h.
[0038] Optionally, the temperature of the second reaction is 80℃~200℃, and the time is 1 h~8 h.
[0039] Optionally, an ether solvent is used to coordinate aluminum ions in aluminum trihalide to prepare a first aluminum complex, and the first aluminum complex and the alkali metal hydride are dissolved in an aprotic solvent to prepare a mixed solution of the first aluminum complex and the alkali metal hydride, comprising:
[0040] A solution of the first aluminum complex was prepared by mixing aluminum trihalide with an aprotic solvent and an ether solvent under an inert gas atmosphere; and
[0041] An alkali metal hydride was added to the solution of the first aluminum complex to prepare a mixed solution of the first aluminum complex and the alkali metal hydride.
[0042] A solution of the first aluminum complex is prepared by first mixing aluminum trihalide with an aprotic solvent and an ether reagent. Then, an alkali metal hydride is added to the solution of the first aluminum complex to prepare a mixed solution of the first aluminum complex and the alkali metal hydride. In this process, there is no need to separate the first aluminum complex from the solution, which improves the preparation efficiency and reduces unnecessary operations and the resulting loss of materials and solubility.
[0043] The inert gas mentioned above can be selected from at least one of nitrogen, argon and helium.
[0044] Optionally, the molar ratio of aluminum trihalide to ether reagent is 1:(1~9). Ether reagent can be used to better coordinate aluminum trihalide, thereby increasing its solubility in aprotic solvents.
[0045] Optionally, the olefin is selected from C2~C3. 12 At least one of the olefins.
[0046] Optionally, the molar ratio of aluminum trihalide, alkali metal hydride and olefin is 1:(1~6):(3~9).
[0047] Compared with related technologies, this application has at least the following beneficial technical effects:
[0048] Using alkali metal hydrides as a hydrogen source to react with aluminum trihalides and alkenes offers several advantages. First, it utilizes the nucleophilic substitution reaction between alkali metal hydrides and aluminum trihalides to prepare aluminum hydride. The reaction conditions are mild, eliminating the need for flammable and explosive hydrogen as a raw material, and the reaction can occur under normal pressure. Second, compared to related technologies that directly react aluminum hydride with alkenes, which have higher costs, this method avoids the direct use of aluminum hydride, reducing costs. Third, compared to related technologies that use metal reduction to prepare alkyl aluminum, the reaction conditions are simpler and easier to implement, and it avoids the separation of aluminum powder and metal salts generated during the reaction, thereby improving reaction efficiency and product yield.
[0049] In addition, the method for preparing alkyl aluminum provided in this application does not require the use of specialized ball milling equipment to prepare highly activated metallic aluminum. Therefore, it does not require a lot of time and materials, thus reducing costs and improving efficiency. Attached Figure Description
[0050] Figure 1 This is a schematic flowchart illustrating a method for preparing alkyl aluminum according to an embodiment of this application. Detailed Implementation
[0051] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.
[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0053] The present application will be further described in detail below with reference to specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.
[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
[0055] In this application, "at least one" means any one, any two, or more of the listed items.
[0056] In this application, the terms "combinations thereof," "any combination thereof," and "any combination thereof" as used include all suitable combinations of any two or more of the listed items.
[0057] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.
[0058] In this application, numerical ranges are involved, and unless otherwise specified, the two endpoints of the numerical range are included.
[0059] In this application, unless otherwise specified, percentage concentrations refer to final concentrations. The final concentration refers to the percentage of the added component in the system after its addition.
[0060] In this application, temperature parameters are involved. Unless otherwise specified, both isothermal processing and processing within a certain temperature range are permitted. The isothermal processing allows temperature fluctuations within the precision range controlled by the instrument.
[0061] The term "alkyl" refers to a saturated hydrocarbon containing a primary (normal) carbon atom, or a secondary carbon atom, or a tertiary carbon atom, or a quaternary carbon atom, or a combination thereof. A phrase containing this term, such as "C1 to C5 alkyl", refers to an alkyl group containing 1 to 5 carbon atoms, and each time it appears, it can be independently referred to as C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, or C5 alkyl. Suitable examples include, but are not limited to: methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(CH3)CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), and 3-pentyl (-CH(CH2CH3)2).
[0062] "Aryl" refers to an aromatic hydrocarbon group derived from an aromatic ring compound by removing one hydrogen atom. It can be a monocyclic aryl, a fused-ring aryl, or a polycyclic aryl. For polycyclic compounds, at least one ring must be an aromatic ring system. For example, "C6~C..." 12"Aryl" refers to an aryl group containing 6 to 12 carbon atoms. Each time it appears, it can be independently C6 aryl or C6 aryl. 12 Aryl groups, suitable examples of which include, but are not limited to, benzene, toluene, biphenyl, and naphthalene.
[0063] In this application, to avoid other reactions between the aryl group in the ether reagent and alkali metal hydrides and / or aluminum chloride, the "aryl group" does not contain heteroatoms.
[0064] To address the problems in current related technologies, such as the need for flammable and explosive hydrogen gas in the preparation of alkyl aluminum, the significant time and material consumption, the complex reaction leading to low product yield, and the difficulty in separating aluminum powder from the metal salts produced in the reaction, the specific embodiments of this application are described as follows:
[0065] Some embodiments of this application provide a method for preparing alkylaluminum, the method comprising:
[0066] Alkyl aluminum is prepared by reacting alkali metal hydrides as hydrogen sources with aluminum trihalides and olefins.
[0067] Alkali metal hydrides are compounds formed by alkali metals (such as lithium, sodium, and potassium) and hydrogen. The hydride anions in alkali metal hydrides can act as nucleophiles to attack the aluminum ions in aluminum trihalide molecules. The hydride anions donate a pair of electrons to form a coordinate bond with the aluminum ions, thereby forming aluminum hydride. Aluminum hydride can then undergo an addition reaction with alkenes to prepare alkyl aluminum.
[0068] In the method for preparing alkylaluminum provided in this application, an alkali metal hydride is used as a hydrogen source to react with aluminum trihalide and an olefin. On the one hand, aluminum hydride is prepared by utilizing the nucleophilic substitution reaction between the alkali metal hydride and aluminum trihalide. The reaction conditions are mild, and there is no need to use flammable and explosive hydrogen as a raw material; the reaction can occur under normal pressure. On the other hand, compared with the related technology that uses aluminum hydride to react directly with an olefin, which has a higher cost, the direct use of aluminum hydride can be avoided, reducing costs. Furthermore, compared with the related technology that uses metal reduction to prepare alkylaluminum, the reaction conditions are simple and easy to implement, and the separation of aluminum powder and metal salts generated during the reaction can be avoided, thereby improving reaction efficiency and product yield.
[0069] In addition, the method for preparing alkyl aluminum provided in this application does not require the use of specialized ball milling equipment to prepare highly activated metallic aluminum. Therefore, it does not require a lot of time and materials, thus reducing costs and improving efficiency.
[0070] In some embodiments, the aluminum trihalide is selected from at least one of aluminum trichloride, aluminum trifluoride, aluminum tribromide, and aluminum triiodide.
[0071] In some embodiments, the alkali metal hydride includes at least one of sodium hydride and potassium hydride.
[0072] In some embodiments, alkali metal hydrides react with aluminum trihalides and olefins in a solvent comprising an aprotic solvent and an ether reagent capable of coordinating with the aluminum trihalide and being separable from the alkylaluminum under heating and / or reduced pressure.
[0073] Aprotic solvents are solvents whose molecules contain no transferable protons. Because aprotic solvent molecules do not contain transferable protons, they do not participate in proton transfer reactions. They are suitable for proton-sensitive reactions, and are especially suitable for dissolving many substances that are difficult to dissolve in protic solvents, such as organometallic compounds.
[0074] In these embodiments, by adding an ether reagent to an aprotic solvent, the solubility of aluminum trihalide in the aprotic solvent can be increased because the ether reagent can coordinate with aluminum trihalide to form an organometallic compound. This facilitates the reaction of aluminum trihalide with alkali metal hydrides to form aluminum hydride, and the reaction of aluminum hydride with alkenes to form alkyl aluminum, thereby improving the reaction efficiency. After the alkyl aluminum is formed, the ether reagent can be separated from the alkyl aluminum by heating and / or reducing the pressure, thus obtaining alkyl aluminum.
[0075] In some embodiments, the aprotic solvent is selected from C5~C6. 14 At least one of the alkanes.
[0076] In some embodiments, the olefin is selected from C2 to C3. 12 At least one of the olefins.
[0077] C2~C 12 The olefin can be a terminal olefin (i.e., an α-olefin, which is an olefin with the olefin bond located at the end of the carbon chain) or an internal olefin (which is an olefin with the olefin bond located in the middle of the carbon chain), and no specific limitation is made here.
[0078] In some embodiments, the molar ratio of the above-mentioned aluminum trihalide, alkali metal hydride and olefin can be 1:(1~6):(3~9).
[0079] In these embodiments, the yield of alkylaluminum can be maximized and the introduction of impurities minimized.
[0080] In some embodiments, the ether reagent comprises one or more compounds of the general formula R1-O-R2;
[0081] Among them, R1 and R2 are independently selected from C6~C6. 12 aryl; or,
[0082] R1 is selected from C1~C5 alkyl groups, and R2 is selected from C6~C5 alkyl groups. 12 In the aryl group, R1 is bonded to O through an m-th carbon atom, where m is an integer from 1 to 3; or,
[0083] R1 and R2 are each independently selected from C1 to C5 alkyl groups, and at least one of R1 and R2 is bonded to O through an n-order carbon atom, where n is an integer from 2 to 3.
[0084] In organic chemistry, carbon atoms are classified into primary, secondary, tertiary, and quaternary carbon atoms based on whether they are directly bonded to one or more other carbon atoms. A primary carbon atom is one directly bonded to a single carbon atom; for example, in propane, the carbon atoms on the methyl groups at both ends are primary carbon atoms. A secondary carbon atom is one directly bonded to two carbon atoms; for example, in 2-butane (CH3CH2CH3), the carbon atom on the middle carbon atom bonded to the methyl groups at both ends is a secondary carbon atom. A tertiary carbon atom is one directly bonded to three carbon atoms; for example, in 2-methylpropane ((CH3)3CH), the middle carbon atom is a tertiary carbon atom. A quaternary carbon atom is one directly bonded to four carbon atoms; for example, in neopentane ((CH3)4C), the middle carbon atom is a quaternary carbon atom.
[0085] Here, R1 is bonded to O through m-level carbon atoms, where m is an integer from 1 to 3. This means that R1 can be bonded to O through primary carbon atoms, secondary carbon atoms, or tertiary carbon atoms. When R1 is bonded to O through primary carbon atoms, the carbon atom in R1 bonded to O is directly connected to one carbon atom; when R1 is bonded to O through secondary carbon atoms, the carbon atom in R1 bonded to O is directly connected to two carbon atoms; and when R1 is bonded to O through tertiary carbon atoms, the carbon atom in R1 bonded to O is directly connected to three carbon atoms.
[0086] For example, when R1 is bonded to O through a primary carbon atom, the primary carbon atom is directly connected to a carbon atom. In this case, R1 can be -CH2-CH3, -CH2-CH2-CH3, -CH2-CH2-CH2-CH3, -CH2-CH(CH3)2, -CH2-CH(CH3)-CH2-CH3, -CH2-C(CH3)3, or -CH2-CH2-CH(CH3)2.
[0087] For another example, when R1 is bonded to O through a secondary carbon atom, the secondary carbon atom is directly connected to two carbon atoms. In this case, R1 can be -CH(CH3)2, -CH(CH3)-CH2-CH3, -CH(CH3)-CH2-CH2-CH3 or -CH(CH3)-CH(CH3)2.
[0088] As another example, when R1 is bonded to O through a tertiary carbon atom, the tertiary carbon atom is directly connected to three carbon atoms. In this case, R1 can be -C(CH3)3 or -C(CH2-CH3)(CH3)2.
[0089] Similarly, if at least one of R1 and R2 is bonded to O through an n-level carbon atom, where n is an integer from 2 to 3, it means that R1 can be bonded to O through a secondary or tertiary carbon atom, in which case R2 can be bonded to O through a primary, secondary, or tertiary carbon atom; or, if R2 is bonded to O through a secondary or tertiary carbon atom, in which case R1 can be bonded to O through a primary, secondary, or tertiary carbon atom. The secondary, tertiary, and primary carbon atoms are described above and will not be repeated here.
[0090] In these embodiments, these ether reagents have significant steric hindrance. Thus, compared with the related art which uses small molecule ethers (such as diethyl ether, tetrahydrofuran, etc.) as solvents to prepare alkylaluminum, where these small molecule ethers are not easy to separate from alkylaluminum, these ether reagents are more easily removed during or after the reaction by heating and / or reducing pressure, thereby releasing the alkylaluminum without affecting its subsequent reactivity, and facilitating the application of alkylaluminum.
[0091] In some embodiments, the ether reagent is selected from at least one of diisopropyl ether, ethyl isopentyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, tert-butylphenyl ether, and isopropylphenyl ether.
[0092] In some embodiments, the molar ratio of the above-mentioned aluminum trihalide and ether reagent is 1:(1~9).
[0093] In these embodiments, ether-based reagents can be used to better coordinate aluminum trihalides, thereby increasing their solubility in aprotic solvents.
[0094] In some embodiments, alkali metal hydrides are used as hydrogen sources to react with aluminum trihalides and olefins to prepare alkylaluminum, such as... Figure 1 As shown, it includes:
[0095] S11. A first aluminum complex is prepared by coordinating aluminum ions in aluminum trihalide with an ether reagent; the ligand of the first aluminum complex comprises halide ions and the ether reagent.
[0096] S12. Dissolve the first aluminum complex and the alkali metal hydride in an aprotic solvent to prepare a mixed solution of the first aluminum complex and the alkali metal hydride;
[0097] S13. The first aluminum complex and the alkali metal hydride undergo a first reaction to generate a first product; the first product includes a second aluminum complex and / or aluminum hydride, and the ligands of the second aluminum complex contain hydrogen ions and ether reagents.
[0098] S14. The first product and the olefin undergo a second reaction to generate a second product, which includes a third aluminum complex and / or alkyl aluminum, and the ligands of the third aluminum complex include alkyl and ether reagents.
[0099] In cases where the second product includes a third aluminum complex, such as Figure 1 As shown, the preparation method also includes:
[0100] S15. The third aluminum complex is heated and / or subjected to reduced pressure to remove the ether reagent from the third aluminum complex, thereby preparing alkyl aluminum.
[0101] In these embodiments, by first preparing a first aluminum complex, which is a product of coordination between an ether reagent and aluminum trihalide, the solubility of aluminum trihalide in aprotic solvents can be effectively improved, thus facilitating the first reaction between the first aluminum complex and the alkali metal hydride. After the first reaction between the first aluminum complex and the alkali metal hydride to form a second aluminum complex, the second aluminum complex is then subjected to a second reaction with an alkene. This effectively reduces the direct reaction of the alkali metal hydride with the alkene to form byproducts such as alkyl sodium and alkynes, thereby improving reaction efficiency and the purity and yield of alkyl aluminum. Furthermore, during the first and second reactions, some ether reagents may detach from the second or third aluminum complex under heating, directly yielding alkyl aluminum. In cases where the second product includes the third aluminum complex, heating and / or vacuum treatment can detach the ether reagent from the third aluminum complex to obtain alkyl aluminum.
[0102] In some embodiments, S11, an ether solvent is used to coordinate aluminum ions in aluminum trihalide to prepare a first aluminum complex, and S12, the first aluminum complex and the alkali metal hydride are dissolved in the aprotic solvent to prepare a mixed solution of the first aluminum complex and the alkali metal hydride, comprising:
[0103] A solution of the first aluminum complex was prepared by mixing aluminum trihalide with an aprotic solvent and an ether solvent under an inert gas atmosphere; and
[0104] An alkali metal hydride was added to the solution of the first aluminum complex to prepare a mixed solution of the first aluminum complex and the alkali metal hydride.
[0105] In these embodiments, a solution of the first aluminum complex is prepared by first mixing aluminum trihalide with an aprotic solvent and an ether reagent, and then adding an alkali metal hydride to the solution of the first aluminum complex to prepare a mixed solution of the first aluminum complex and the alkali metal hydride. In this process, there is no need to separate the first aluminum complex from the solution, which improves the preparation efficiency and reduces unnecessary operations and the resulting loss of materials and solubility.
[0106] In some embodiments, the inert gas is selected from at least one of nitrogen, argon, and helium.
[0107] In some embodiments, in S13 above, the temperature of the first reaction is 50°C to 100°C, and the time is 0.5 h to 12 h. Optionally, the temperature of the first reaction is 60°C to 100°C, and the time is 1 h to 10 h.
[0108] In these embodiments, the first aluminum complex can be made to react with the alkali metal hydride to form the second aluminum complex as much as possible, thereby reducing the reaction of the alkali metal hydride with the olefin to form byproducts.
[0109] In some embodiments, in S14 above, the temperature of the second reaction is 80°C to 200°C, and the time is 1 h to 8 h.
[0110] In these embodiments, the second aluminum complex and the olefin can be reacted as much as possible to generate a third aluminum complex and / or alkyl aluminum, thereby increasing the yield and reducing impurities.
[0111] In some embodiments, both the first and second reactions are carried out in solution;
[0112] S15. Heating and / or reducing pressure on the third aluminum complex to remove the ether solvent from the third aluminum complex, to prepare alkylaluminum, including:
[0113] The reaction solution after the second reaction was subjected to vacuum distillation so that the ether solvent was removed from the third aluminum complex and evaporated.
[0114] In these embodiments, the ether solvent can be removed from the third aluminum complex and evaporated away by vacuum distillation, which can improve efficiency and reduce ether reagent residue.
[0115] In some embodiments, the vacuum distillation process is carried out at a temperature of 80°C to 100°C and a pressure of 0.01 MPa to 0.1 MPa (absolute pressure). Optionally, the vacuum distillation process is carried out at a temperature of 80°C to 90°C and a pressure of 0.02 MPa to 0.08 MPa.
[0116] The specific implementation methods of this application have been described above. In order to objectively explain the technical effects produced by this application, the following embodiments will be used to describe them.
[0117] In the following embodiments, all raw materials are commercially available, and to maintain the reliability of the experiments, the raw materials used in the following embodiments have the same physical and chemical parameters or have undergone the same treatment.
[0118] Example 1
[0119] Example 1 provides an alkyl aluminum, the preparation method of which is as follows:
[0120] Step 1) Add 20 g of aluminum trichloride (0.15 mol) to a 250 mL reactor, then add 120 mL of n-hexane solution, then add 17.63 methyl tert-butyl ether (0.2 mol) as an auxiliary reagent, stir the solution, and then add 10.8 g of sodium hydride (0.45 mol) to the solution to obtain a mixed solution.
[0121] Step 2) Raise the temperature of the mixed solution to 60°C and maintain this temperature for 2 hours.
[0122] Step 3) Slowly add 50.51 g of 1-octene (0.45 mol) to the solution obtained in Step 2), and the reaction temperature rises rapidly. Control the rate of octene addition and maintain the reaction solution temperature at 115 °C. After the octene has been completely added, maintain the reaction solution at 115 °C for 2 hours, then stop the reaction. Filter the product solution, heat the filtrate to 80 °C, and remove the solvent from the filtrate under reduced pressure (absolute pressure) of 0.08 MPa to obtain 52.71 g of trioctylaluminum with a purity of 96% and a yield of 92%.
[0123] The yield and purity of trioctylaluminum can be measured by NMR internal standard method, with toluene as the internal standard. The specific operation is as follows: take a quantitative amount of product solution (i.e., trioctylaluminum after solvent removal), mix the product solution and toluene at a mass ratio of 1:2, and determine the amount of trioctylaluminum in the product solution based on the characteristic peak area ratio of toluene and trioctylaluminum. Thus, the yield and purity of trioctylaluminum can be determined.
[0124] Example 2
[0125] The preparation method of alkyl aluminum provided in Example 2 is basically the same as that in Example 1, except that:
[0126] In step 1), 0.15 mol of aluminum tribromide is used as the raw material, and ethyl isopentyl ether is used as the auxiliary reagent. The molar ratio of aluminum tribromide to ethyl isopentyl ether is 1:1, and the molar ratio of aluminum tribromide to sodium hydride is 1:1.
[0127] In step 2), the temperature is raised to 50°C and maintained at this temperature for 6 hours.
[0128] In step 3), 1.35 mol of 1-butene was added, the reaction solution temperature was maintained at 80℃, and the reaction was carried out at a constant temperature for 8 hours. The filtrate was heated to 80℃, and the solvent in the filtrate was removed under reduced pressure (absolute pressure) of 0.05 MPa. Finally, the yield of tributylaluminum was 95%, and the purity was 91%.
[0129] The yield and purity of tributylaluminum can also be measured by NMR internal standard method, with toluene as the internal standard. For specific operation, please refer to the method for determining the yield and purity of trioctylaluminum in Example 1, which will not be repeated here.
[0130] Example 3
[0131] The preparation method of alkyl aluminum provided in Example 3 is basically the same as that in Example 1, except that:
[0132] In step 1), 0.15 mol of aluminum triiodide is used as the raw material, and tert-butylphenyl ether is used as the auxiliary reagent. The molar ratio of aluminum triiodide to tert-butylphenyl ether is 1:6, and the molar ratio of aluminum triiodide to sodium hydride is 1:6.
[0133] In step 2), the temperature is raised to 100°C and maintained at this temperature for 10 hours.
[0134] In step 3), 0.9 mol of 1-dodecene was added, the reaction solution temperature was maintained at 200℃, and the reaction was carried out at a constant temperature for 1 h. The filtrate was heated to 90℃, and the solvent in the filtrate was removed under reduced pressure (absolute pressure) of 0.02 MPa. The final yield of tri(dodecyl aluminum) was 94%, and the purity was 97%.
[0135] The yield and purity of tri(dodecyl aluminum) can also be measured by NMR internal standard method, with toluene as the internal standard. For specific operation, please refer to the method for determining the yield and purity of trioctyl aluminum in Example 1, which will not be repeated here.
[0136] Test case
[0137] The alkylaluminum prepared in Examples 1-3 were structurally characterized, and the results are as follows:
[0138] NMR data of alkylaluminum prepared in Example 1: 1 H NMR (C6D6, 500MHz, 25 ℃): δ0.56 (t, 6H, AlCH2); 0.92 (t, 9H, CH3); 1.2-1.5 (30H, CH2); 1.62 (m, 6H, AlCH2CH2).
[0139] NMR data of alkylaluminum prepared in Example 2: 1 H NMR (C6D6, 500MHz, 25 ℃): δ0.28 (d, 6H, CH2); 1.03 (d, 18H, CH3); 1.95 (3H, m, AlCH).
[0140] NMR data of alkylaluminum prepared in Example 3: 1 H NMR (C6D6, 500MHz, 25 ℃): δ0.61 (t, 6H, AlCH2); 0.90 (t, 9H, CH3); 1.2-1.5 (54H, CH2); 1.57 (m, 6H, AlCH2CH2).
[0141] As can be seen, all three examples prepared alkylaluminum with high purity and yield, and the preparation methods are simple and easy to implement, making it convenient for the direct application of alkylaluminum.
[0142] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0143] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A method for producing an alkylaluminum, characterized by, The method comprises: reacting an alkali metal hydride as a hydrogen source with an aluminum trihalide and an olefin to produce the alkyl aluminum.
2. The method for producing an aluminum alkyl according to claim 1, characterized by, The alkali metal hydride comprises at least one of sodium hydride and potassium hydride.
3. The method of producing an alkylaluminum according to claim 1, wherein The alkali metal hydride is reacted with the aluminum trihalide and the olefin in a solvent, the solvent comprising an aprotic solvent and an ether reagent capable of being coordinated with the aluminum trihalide and capable of being separated from the alkyl aluminum under heating and / or reduced pressure.
4. The method for producing an alkylaluminum according to claim 3, characterized by, The ether reagent is selected from one or more of compounds of the general formula R1-O-R2; wherein R1and R2are each independently selected from C6-Ci2aryl; or, alternatively, 12 C6-Ci2aryl; or, alternatively, R1is selected from the group consisting of C1-C5 alkyl, R2is selected from the group consisting of C6-C10 aryl, R1is bonded to O through an m level carbon atom, m is an integer from 1 to 3; or, 12 R1is selected from the group consisting of C1-C5 alkyl, R2is selected from the group consisting of C6-C10 aryl, R1is bonded to O through an m level carbon atom, m is an integer from 1 to R1 and R2 are each independently selected from C1-C5 alkyl groups, and at least one of R1 and R2 is bonded to O through an n-level carbon atom, n being an integer of 2-3.
5. The method for producing an alkylaluminum according to claim 4, characterized by, The ether reagent is selected from at least one of diisopropyl ether, ethyl isopropyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, tert-butyl phenyl ether, and isopropyl phenyl ether.
6. The process for producing an alkylaluminum according to any one of claims 3 to 5, characterized in that, The method for producing the alkyl aluminum by reacting an alkali metal hydride as a hydrogen source with an aluminum trihalide and an olefin comprises: The ether reagent is used to coordinate aluminum ions in the aluminum trihalide to produce a first aluminum complex; the ligand of the first aluminum complex comprises halide ions and the ether reagent; The first aluminum complex and the alkali metal hydride are dissolved in the aprotic solvent to produce a mixed solution of the first aluminum complex and the alkali metal hydride; The first aluminum complex and the alkali metal hydride are allowed to undergo a first reaction to produce a first product; the first product comprises a second aluminum complex and / or aluminum hydride, the ligand of the second aluminum complex comprising hydrogen ions and the ether reagent; The first product and the olefin are allowed to undergo a second reaction to produce a second product, the second product comprising a third aluminum complex and / or the alkyl aluminum, the ligand of the third aluminum complex comprising alkyl groups and the ether reagent; In the case where the second product comprises a third aluminum complex, the method further comprises: The third aluminum complex is heated and / or subjected to reduced pressure treatment to allow the ether reagent to be separated from the third aluminum complex to produce the alkyl aluminum.
7. The method of producing an alkylaluminum according to claim 6, wherein Both the first reaction and the second reaction are carried out in solution; The third aluminum complex is heated and / or subjected to reduced pressure treatment to allow the ether reagent to be separated from the third aluminum complex to produce the alkyl aluminum, comprising: The reaction solution after the second reaction is subjected to vacuum distillation treatment to allow the ether reagent to be separated from the third aluminum complex and evaporated and removed; Optionally, the temperature of the vacuum distillation treatment is 80-100°C, and the pressure is 0.01-0.1 MPa.
8. The method for producing the alkyl aluminum according to claim 6, wherein: The temperature of the first reaction is 50-100°C, and the time is 0.5-12 h; and / or The temperature of the second reaction is 80-200°C, and the time is 1-8 h.
9. The method of producing an alkylaluminum according to claim 6, wherein The ether solvent is used to coordinate aluminum ions in the aluminum trihalide to prepare a first aluminum complex, and the first aluminum complex and the alkali metal hydride are dissolved in the aprotic solvent to prepare a mixed solution of the first aluminum complex and the alkali metal hydride, including: The aluminum trihalide is mixed with the aprotic solvent and the ether solvent under an inert gas atmosphere to prepare a dissolved solution of the first aluminum complex; and The alkali metal hydride is added to the dissolved solution of the first aluminum complex to prepare a mixed solution of the first aluminum complex and the alkali metal hydride.
10. The method of claim 6, wherein: a molar ratio of the aluminum trihalide to the ether reagent is 1: (1-9); and / or a molar ratio of the aluminum trihalide, the alkali metal hydride, and the olefin is 1: (1-6): (3-9).