Efficient preparation of organoaluminum compounds
The compound of formula (I) is prepared by reacting dialkylaluminum hydride with aluminum trichloride, which solves the problem of using difficult-to-prepared trialkylaluminum compounds in the prior art, and realizes a method for efficient preparation of organic aluminum chloride, which is suitable for catalytic applications in oligomerization and polymerization reactions.
Patent Information
- Application Number
- CN202411258240.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-09-15
- Filing Date
- 2024-09-09
- Publication Date
- 2025-03-18
AI Technical Summary
In the prior art, difficult-to-prepared trialkylaluminum compounds are required to be used when preparing organic aluminum chloride, resulting in insufficiently efficient preparation.
The compound R1nAlCl(3-n) of formula (I) is prepared by reacting dialkylaluminum hydride with aluminum trichloride, which is easier to implement and efficient.
This method can prepare different quality of organic aluminum chloride in a smooth and efficient reaction, and is suitable as a catalyst or cocatalyst in oligomerization and polymerization reactions.
Abstract
Description
Technical Field
[0001] The present invention relates to an efficient method for preparing organic aluminum chloride from dialkylaluminum hydrides of different qualities. Background Art
[0002] Organoaluminium compounds, in particular halogenated organoaluminium compounds, are generally known and widely used, for example, in the production of polymers, such as polyolefins (like ethylene homopolymers and copolymers) or as (co-)catalysts in olefin metathesis.
[0003] Wiberg, Schmidt; Zeitung für Naturforschung [Journal of Nature Research], 6b, pp. 460-461 discloses the hydrogen chloride exchange of alan AlH3 and aluminum trichloride. However, this document does not mention alkyl-containing aluminum compounds.
[0004] Typically, the organoaluminium chloride is prepared by reacting a trialkylaluminium compound with aluminium trichloride or a defined chloroaluminium compound such as a dialkylaluminium chloride or an alkylaluminium dichloride.
[0005] However, the above procedures require the use of trialkylaluminum compounds which are difficult to prepare at least for some alkyl substituents. Summary of the invention
[0006] In view of the above situation, there is still a need to provide a method for preparing organic aluminum chloride that is easy to implement.
[0007] Therefore, there is now provided a process for preparing a compound of formula (I)
[0008] R 1 n AlCl (3-n) (I)
[0009] in
[0010] R 1 represents an alkyl or cycloalkyl group which is unsubstituted or substituted once by a phenyl group, and
[0011] n is 0.5 to 2.5, preferably 0.8 to 1.2 or 1.4 to 1.6 or 1.8 to 2.2, for example 1 or 1.5 or 2
[0012] The method comprises at least the following steps: making a compound of formula (II)
[0013] R 1 2AlH(II)
[0014] Reacts with aluminum chloride.
[0015] The scope of the present invention encompasses all combinations of substituent definitions, preferred ranges or preferred embodiments with one another, ie also any combination of specified ranges and preferred ranges.
[0016] Whenever used herein, the terms "including", "for example" and "such as" mean "including but not limited to" or "for example but not limited to", respectively.
[0017] As used herein, aluminum trichloride refers to aluminum trichloride free of water, wherein free of water means a water content of less than 1 wt.-%, preferably less than .
[0018] It is known to those skilled in the art that the compounds of formula (I) and (II) may exist in dimeric or oligomeric, preferably dimeric or trimeric structures, in which hydrogen or chlorine serves as a bridging ligand. These forms are also covered by the general formula (I) and (II).
[0019] For example, when n is 1.5, Formula (I) includes compounds comprising the following structure:
[0020] Exemplary dimeric structure of the compound of formula (I) when n=1.5
[0021] As used herein, and unless specifically indicated otherwise, "alkyl" may be branched or unbranched.
[0022] As used herein, and unless specifically indicated otherwise, a "cycloalkyl" group may be partially or fully cyclic.
[0023] Preferably, "alkyl" means unsubstituted or once substituted by phenyl, preferably unsubstituted C2-C 18 In some embodiments, the present invention relates to alkyl, alkyl, alkyl, alkyl, alkyl radicals ...
[0024] Preferably, "cycloalkyl" means unsubstituted or once substituted by phenyl, preferably unsubstituted C3-C 18 -cycloalkyl, even more preferably C5-C 18 -cycloalkyl. The index at a carbon atom indicates the number of carbon atoms, which does not include the carbon atoms of the optionally present phenyl substituent. 18Specific examples of the -cycloalkyl group are cyclopentyl, cyclohexyl, methylcyclohexyl, among which cyclohexyl is preferred.
[0025] Preferred compounds of formula (I) are diethylaluminum chloride (DEAC) and ethylaluminum dichloride (EADC), ethylaluminum sesquichloride (EASC), diisobutylaluminum chloride (DIBAC) and isobutylaluminum dichloride (IBADIC) and isobutylaluminum sesquichloride and mixtures thereof.
[0026] Preferred compounds of formula (II) are diisobutylaluminium hydride (DIBAH), diethylaluminium hydride.
[0027] The molar ratio of the compound of formula (II) to aluminum chloride depends on the desired product of formula (I) to be prepared and is generally selected so that for 1 mol of R present in the desired product of formula (I) 1 It is 0.25 to 0.4, preferably 0.3.
[0028] The compounds of formula (II) can be used, for example, in the form of pure substances with a purity of, for example, 98 wt.-% or more. However, compounds of lower purity, for example with a purity of 80 wt. % to less than 98 wt. %, have also been found to be suitable.
[0029] Typically, these qualities are obtained as reaction residues from the preparation of dialkylaluminum hydrides which involves reacting aluminum with olefins and hydrogen in a manner known to those skilled in the art, followed by distillation or filtration.
[0030] Such qualities may include (unreacted) aluminum, aluminum oxides, as well as iron, zirconium, titanium, and oxides of iron, zirconium and titanium.
[0031] These components were found not to significantly interfere with the reaction according to the invention.
[0032] The reaction of the compound of formula (II) and aluminum chloride can be carried out as neat or in the presence of a non-coordinating solvent.
[0033] As used herein, the term "non-coordinating solvent" means that the solvent molecule does not contain oxygen, sulfur or nitrogen atoms. For example, non-coordinating solvents include aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane (each of which is in any possible isomerically pure form or in an isomer mixture), mineral oil, or any mixture of the above aliphatic hydrocarbon solvents. Preferred non-coordinating solvents include n-pentane, isopentane, pentane, n-hexane, isohexane, hexane, n-heptane, isoheptane, heptane, with heptane being preferred.
[0034] This process can be carried out batchwise or continuously, preferably batchwise.
[0035] The reaction time in a batch process and the residence time in a continuous process is, for example, from 30 seconds to 24 hours, preferably from 30 minutes to 12 hours.
[0036] The process according to the invention can be carried out, for example, in any reactor which allows such a reaction, for example a tubular reactor with mixing nozzles in the case of a continuous process, or a stirred tank for a batch process.
[0037] The process according to the invention is carried out at a temperature of, for example, -20 to 150°C, preferably at a temperature of 0 to 130°C and even more preferably at a temperature of 15 to 125°C.
[0038] The reaction pressure is not very critical and in step 1) may be from 1000 hPa to 5 MPa, preferably from 900 hPa to 1 MPa, even more preferably at ambient pressure.
[0039] Without wishing to be bound by theory, it is assumed that aluminum hydride AlH 3 is formed during the reaction, which decomposes to form gaseous hydrogen and finely distributed aluminum.
[0040] In order to remove the latter and other (solid) impurities which may have formed during the reaction or have been introduced into the reaction together with the reactants, the process of the invention may further comprise an additional step of purifying the compound of formula (I).
[0041] This task can be performed by any means known to those skilled in the art, separating solids or other impurities from the desired compound of formula (I) by filtration, centrifugation or decantation and / or distillation, with distillation being preferred.
[0042] The compounds of formula (I) prepared according to the invention are particularly suitable for use in oligomerization and polymerization reactions, such as olefins (preferably isobutylene, butadiene or ethylene or propylene) with or without C2-C 20 The olefins are used as catalysts or cocatalysts in the oligomerization and polymerization of olefins as comonomers and in the metathesis of oligomers or polymers.
[0043] As used herein, "oligomer" shall mean a compound comprising from 2 to 8 structural (repeating) units derived from one or more olefins employed in the "oligomerization" reaction.
[0044] As used herein, "polymer" shall mean a compound comprising 9 or more, for example 9 to 500,000 structural (repeating) units derived from one or more olefins employed in a "polymerization" reaction.
[0045] Thus, one aspect of the present invention relates to metathesis, oligomerization and polymerization reactions, preferably oligomerization or polymerization of olefins, more preferably isobutylene, butadiene, ethylene or propylene with or without C2-C 20 Oligomerization or polymerization with olefins as comonomers, wherein the compounds of the formula (I) prepared according to the invention are used as (co-)catalysts.
[0046] The main advantage of the present invention is that the compound of formula (I) can be prepared from organoaluminum hydrides of different qualities in a smooth and efficient reaction. DETAILED DESCRIPTION
[0047] The following examples are intended to illustrate the present invention, but the present invention is not limited thereto.
[0048] experiment:
[0049] Overview
[0050] Analytical methods
[0051] Sample preparation:
[0052] Weigh an appropriate amount of sample into a flask and dilute with an inert solvent. Decompose the organoaluminum compound by adding acetate buffer and an appropriate amount of EDTA solution. Support the formation of the aluminum EDTA complex and the evaporation of the organic solvent by heating on a hot plate.
[0053] Determination of aluminum content:
[0054] This procedure applies to all organoaluminum compounds. During sample preparation, aluminum forms a complex with excess EDTA. 2+ The solution was back-titrated with excess EDTA to determine the aluminum content.
[0055] Determination of chlorine content:
[0056] This procedure is applicable to products containing chlorine which are obtainable in ionic form by sample preparation. The chlorine is titrated with silver nitrate solution in a potentiometric titration. Two independent determinations are carried out. The absolute chlorine content in the sample is calculated from the amount of silver nitrate consumed.
[0057] purity
[0058] Purity was determined by gas chromatography.
[0059] Examples
[0060] All manipulations were performed using the Schlenk technique under protective gas.
[0061] 1) Preparation of isobutylaluminum dichloride
[0062] 34.40 g of diisobutylaluminum hydride (DIBAH, minimum purity 96 wt-% DIBAH) were charged to the flask at 25°C. 21.30 g of aluminum chloride were then added in one go, at which point the internal temperature rose to 48°C. The temperature of the external heating was raised to 30°C, and a second amount of aluminum chloride was added in one go without observing any further temperature rise. The reaction mixture was heated to 80°C and stirred at this temperature for 2 hours. After one hour at 80°C, a gray solid was formed. The temperature of the external heating was raised to 120°C, and finally, the reaction mixture was distilled at 10 mbar. A clear, colorless liquid was obtained.
[0063] Yield: 65.3 g (87% of theory)
[0064] Analytical data: 17.80 m / m% Al, 46.34 m / m% Cl, 99.23 n / n% isobutane
[0065] 2) Preparation of isobutylaluminum dichloride
[0066] At 25°C, 88.79 g of diisobutylaluminium hydride (91.4% DIBAH content, 10% total solid content calculated as Al, corresponding to 8.6 wt-%) were loaded into the flask. Then 55.50 g of aluminium chloride was added once, and the internal temperature was raised to 34°C. The temperature of external heating was raised to 30°C, and the second amount of aluminium chloride was added once without observing any further temperature rise. The reaction mixture was heated to 110°C and stirred at this temperature for 2 hours. The temperature of external heating was raised to 120°C. 25 g of high boiling saturated oil (paraffin fuel) was added and the reaction mixture was distilled at 10 mbar. A transparent colourless liquid was isolated.
[0067] Yield: 171.8 g (87% of theory)
[0068] Analytical data: 17.54 m / m% Al, 46.63 m / m% Cl, 99.91 n / n% isobutane.
Claims
1. A method for preparing a compound of formula (I) R 1 n AlCl (3-n) (I) in R 1 represents an alkyl or cycloalkyl group which is unsubstituted or substituted once by a phenyl group, and n is 0.5 to 2.5, preferably 1 or 1.5 or 2, The method comprises at least the following steps: making a compound of formula (II) <h2 style=";text-align:left;direction:ltr">R<h2 style=";text-align:left;direction:ltr"> 1 <h2 style=";text-align:left;direction:ltr"> 2AlH(II) Reacts with aluminum chloride.
2. The method according to claim 1, wherein: R 1 represents unsubstituted or once substituted C2-C 18 -alkyl, more preferably unsubstituted or once substituted by phenyl C2-C8-alkyl, and even more preferably ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, n-decyl, n-dodecyl, of which ethyl, isobutyl, n-butyl, sec-butyl, n-hexyl, 2-ethylhexyl and n-octyl are further preferred, and isobutyl is most preferred.
3. The method according to claim 1, wherein: The compound of formula (I) is selected from the group consisting of diethylaluminium chloride (DEAC) and ethylaluminium dichloride (EADC), ethylaluminium sesquichloride (EASC), diisobutylaluminium chloride and isobutylaluminium dichloride.
4. The method according to claim 1, wherein: The compound of formula (II) is selected from the group consisting of diisobutylaluminium hydride (DIBAH) and diethylaluminium hydride.
5. The method according to any one of claims 1 to 4, wherein: The molar ratio of the compound of formula (II) to aluminum chloride is selected so that for 1 mol of R present in the desired compound of formula (I) 1 , using 0.25 to 0.4, preferably 0.30 mol of aluminum chloride.
6. The method according to any one of claims 1 to 5, wherein: The purity of the compound of formula (II) is 80% or more, preferably 98 wt% or more or 80 wt% to less than 98 wt%.
7. The method according to any one of claims 1 to 6, wherein: The compound of formula (II) has a purity of 80 wt % to less than 98 wt % and represents a reaction residue originating from the preparation of dialkylaluminum hydride.
8. The method according to any one of claims 1 to 7, wherein: The reaction of the compound of formula (II) and aluminum chloride can be carried out as neat or in the presence of a non-coordinating solvent.
9. The method according to any one of claims 1 to 8, wherein: The method is carried out batchwise or continuously, preferably batchwise.
10. The method according to any one of claims 1 to 9, wherein: The reaction temperature is -20°C to 150°C, preferably 0°C to 130°C and even more preferably 15°C to 125°C.
11. The method according to any one of claims 1 to 10, wherein: The process comprises as a further step purifying the compound of formula (I), preferably by filtration, centrifugation or decantation and / or distillation, wherein distillation is even more preferred.
12. A process for the metathesis of oligomers or polymers or for the oligomerization and polymerization of olefins, wherein a compound of the formula (I) prepared according to the invention is used as catalyst or cocatalyst.