Understanding Organoaluminum Reagents: From the Al–C Bond to Structural Speciation, Classification, and Three Major Application Domains (Polymerization / Synthesis / ALD)
Understanding Organoaluminum Reagents: From the Al–C Bond to Structural Speciation, Classification, and Three Major Application Domains (Polymerization / Synthesis / ALD)
1.Why Understand Organoaluminum Reagents: They Are Central in Polymerization, Synthesis, and Materials
“Organoaluminum reagents” may look like a niche class of organometallics, but they have long occupied a central position in several key technology chains:
1. Polyolefin (PE/PP, etc.) polymerization: In traditional two-component Ziegler–Natta systems and many other olefin polymerization platforms, organoaluminum compounds often serve as critical components related to co-catalysis / impurity scavenging / activation. They can determine whether a system starts reliably, how sensitive it is to impurities, and whether scale-up is prone to fluctuations.
2. Single-site / metallocene polymerization systems: Aluminoxanes such as MAO (methylaluminoxane) are commonly used as activators/ionizers to convert metallocene precursors into polymerization-active species. Their effective components and equilibrium speciation are complex, but mature industrial dosage and process windows have been established.
3. Materials and semiconductor thin films (ALD/CVD): For example, trimethylaluminum (TMA) + water for Al₂O₃ atomic layer deposition (ALD) is one of the most classic and widely used “benchmark reaction pairs” in materials processing.
4. Organic synthesis: Represented by DIBAL-H (diisobutylaluminum hydride), organoaluminum hydrides are widely used for selective reductions (e.g., esters to aldehydes) and have well-established practices in process scale-up.
2.Basic Definition: What Is “Organoaluminum”?
2.1 Definition
“Organoaluminum” typically refers to aluminum compounds that contain an aluminum–carbon bond (Al–C) and belong to the category of organoaluminum compounds. The key criterion is whether there is a direct bond between the aluminum atom and the carbon atom of an organic group.
2.2 “Organoaluminum” ≠ “Organic Substance + Aluminum Element”
To avoid conceptual confusion, the following distinction is important:
1. Organoaluminum: Characterized structurally by Al–C (typical examples include R₃Al, R₂AlX, R₂AlH, aluminoxanes, etc.).
2. Common aluminum salts / aluminum complexes: Compounds that contain only coordination bonds such as Al–O or Al–N and no Al–C bond are not considered typical “organoaluminum reagents” (even if they may participate in certain catalytic or materials processes).
The main line of this article follows Al–C; a few industrially common aluminum hydrides are listed separately as references/alternatives because their use scenarios are strongly related.
2.3 Common Oxidation States and Commercial Forms
Most common organoaluminum reagents are primarily in the Al(III) form. Because these compounds are typically highly reactive and extremely sensitive to air (oxygen and moisture) and water, they are often supplied industrially and in laboratories as hydrocarbon solutions (e.g., toluene, hexane, heptane, or isoparaffins as solvents), with sealed packaging and inert protection. This approach reduces the risk of contact with air/water and also allows reagents to be supplied at known concentration/content, enabling stable dosing based on effective equivalents and improving batch-to-batch reproducibility.
3.Structural Features: Four “Molecular-Level Structures” Determine Reactivity and Use Patterns
Organoaluminum chemistry spans broad applications, yet performance can change dramatically with conditions. The key reasons are: an electron-deficient aluminum center (strong Lewis acidity), common aggregation/adduct speciation, and high sensitivity to water/oxygen. These structural features translate directly into behavior differences observable in experiments and processes.
Core structure (molecular level) | Typical “chemical state” in practice | What you directly experience in experiments/processes | Implications for application and selection |
1. Electron deficiency: Al(III) readily “accepts electron pairs” (strong Lewis acid) | Al(III) often acts as an electron-pair acceptor; it readily coordinates with O/N-containing donors (solvents, additives, impurities) to form adducts, or reacts with water/oxygen-containing impurities | Extremely sensitive to trace water, oxygen, and O/N-containing species; even under nominally identical conditions (same concentration/formulation), rate, induction period, and selectivity may differ markedly | Enables impurity scavenging and activation assistance, but also means higher requirements on solvent choice, additives, drying, and purity (“change the environment, change the behavior”) |
2. Tendency to aggregate: many R₃Al species are not monomeric | Typical example: TMA often exists as the dimer Al₂Me₆, with bridging alkyl groups in multicenter bonding; aggregation equilibria can change with concentration/temperature; TEAl and many other R₃Al species also commonly appear as Al₂R₆ | The “nominal formula” is not necessarily the “effective reactive species”; changes in temperature, concentration, and feeding mode can shift rates and side-reaction profiles | Explains why the same reagent can behave very differently at different concentrations/temperatures; also why small condition differences are often amplified in polymerization and precursor/material systems |
3. Readily forms adducts: the coordination environment can reshape aggregation and coordination number | Ethers/amines and other donors can form adducts R₃Al·D (D = donor) and may alter the original aggregation form and the distribution of effective species | Switching from non-coordinating hydrocarbon solvents to ether/amine-containing systems can significantly change reactivity, selectivity, exothermicity, and side-reaction channels | Directly determines whether a solvent/additive is usable, how much to use, and when to add it; crucial for reproducibility (differences are more easily amplified upon scale-up) |
4. Air/water sensitivity: reactivity is inseparable from safety | Many common alkylaluminum/aluminum hydride solutions (e.g., TEAL, TMA, DIBAL-H) may be pyrophoric in air and react violently with water, releasing flammable gases | Requires strict exclusion of water/oxygen; typically supplied/handled as hydrocarbon solutions under inert gas; feeding and quenching conditions strongly affect both risk and outcome | This is the chemical basis of strong scavenging/activation performance, and it also means selection must account for solvent form, concentration standardization, packaging, and compliance/safety |
4.Product Classification (by Ligand Type)
Family (classification basis) | General formula / structural tag | Key properties | Typical application domains | Common representatives |
Trialkylaluminum (pure hydrocarbon ligands) | R₃Al (often aggregated/dimeric) | Strong Lewis acid; high reactivity | Polymerization co-catalysts/scavengers; materials precursors | TMA, TEAL, TIBA |
Halogenated organoaluminum (tunable acidity/reactivity) | R₂AlX, RAlX₂ (X = Cl/Br…) | More “tunable” Lewis acidity / alkylating ability | Polymerization system tuning; activation promotion (common co-catalyst family) | DEAC (Et₂AlCl), EADC (EtAlCl₂), etc. |
Sesquihalides (an important branch of halides) | R₃Al₂X₃ (empirical; Cl:Al ≈ 1.5) | “Mixed halides” between R₃Al and R₂AlX | High-frequency co-catalysts in industrial polymerization/catalysis | EASC (Et₃Al₂Cl₃) |
Alkylaluminum hydrides (reducing type) | R₂AlH (often aggregated) | Synergy of “Lewis acidity + hydride transfer” | Selective reductions (synthesis/process) | DIBAL-H, etc. |
Aluminoxanes (activation-related systems) | (R–Al–O)ₙ (mixed aggregates; non-single composition) | Complex but effective activation-related species | Activation for single-site/metallocene olefin polymerization | MAO |
Modified aluminoxanes | MMAO / aluminoxanes with different alkyl substitution | Engineering trade-offs in operability/solubility/activation performance | Activation for single-site/metallocene polymerization (one common industrial product form) | MMAO (multiple commercial grades) |
Alkylaluminum–oxygen-ligand derivatives (still contain Al–C) | R₂AlOR, RAl(OR)₂; also bulky aluminum aryloxides / “designed” Lewis acids | More “designable” coordination environment; more controllable selectivity | Lewis-acid catalysis/controlled transformations in organic synthesis; some systems also as polymerization co-catalyst variants | Representative “bulky aluminum aryloxide” families (e.g., MAD/MAT types) |
Organoaluminate / ate complexes | [AlR₄]⁻, etc. (salts/complexes with Li/Na, etc.) | Anionic character; often “stronger carbon-end nucleophilicity/transfer” (system-dependent) | Transmetalation/additions in methodology/special systems | Lithium tetramethylaluminate, etc. |
Functionalized organoaluminum (R–Al) | Alkenyl/alkynyl/aryl R–Al (can be R₃Al, R₂AlX, etc.) | Can serve as “carbon-fragment carriers/transfer reagents” (strongly system-dependent) | Methodology and specific synthetic routes | Mostly customized/niche products |
5.Typical Application Map: In Three Major Fields, What Problems Does Organoaluminum Solve?
Application scenario (common) | What this field cares about most (goal) | What organoaluminum mainly does | Common organoaluminum types | Representative reagents |
Olefin polymerization (Ziegler–Natta / single-site systems) | Reliable start-up and sustained operation: less “sensitive” to trace water/oxygen/polar impurities; more stable upon scale-up | Impurity scavenging (scavenger); activation/alkylation-related roles (help generate active species) | Trialkylaluminum; halogenated / sesquihalides; aluminoxanes / modified aluminoxanes | TEAL, TIBA, DEAC/EASC, MAO/MMAO |
Organic synthesis (selective reduction as a representative case) | One class aims to stop reduction at the target oxidation state (e.g., esters/lactones stopping at aldehydes); another class aims to “deliver/transfer” carbon fragments in a controlled way (subsequent construction of C–C/C–X bonds; system-dependent) | (1) Selective hydride transfer by aluminum hydrides (often synergistic with Lewis acidity); (2) Hydroalumination of alkenes/alkynes to form organoaluminum intermediates, which can add to carbonyls or undergo transmetalation/coupling under Ni/Pd catalysis (system-dependent) | Aluminum hydrides; organoaluminum intermediates (e.g., in situ–generated R–Al species from hydroalumination) | DIBAL-H (selective reduction); (hydroalumination → downstream transformations are typically in situ intermediate routes) |
Materials / semiconductor thin films (ALD Al₂O₃ as a benchmark) | Controlled film growth: thickness/uniformity controlled; reaction proceeds stepwise by surface-limited processes | Metal–organic precursor (self-limiting surface reactions enable precise control) | Trialkylaluminum (volatile-precursor route) | TMA |
6.Safety and Common Commercial Forms
The hazards of organoaluminum reagents are not incidental—they are intrinsic consequences of their high reactivity (Lewis acidity and readiness to react with water/oxygen). Many common alkylaluminum and aluminum hydride reagents (e.g., triethylaluminum, trimethylaluminum, DIBAL-H) are explicitly labeled in public SDS documents as potentially pyrophoric in air and as undergoing strongly exothermic decomposition upon contact with water/alcohols. R₃Al species typically release alkanes (e.g., CH₄/C₂H₆), while Al–H systems may also release H₂. Therefore, before operation, one must plan the quench strategy and the vent path to avoid local accumulation of heat and flammable gases.
For this reason, commercial organoaluminum products are typically supplied in more “controllable” forms rather than as ordinary solids to be opened and weighed directly:
1. Hydrocarbon solution form: The solvent “dilutes” reactivity to a manageable level and facilitates more stable dosing by volume or mass.
2. Sealed packaging with inert protection: Reduces opportunities for contact with air/moisture and lowers risks during transportation and storage.
3. Clearly specified concentration/content: Enables users to dose by effective equivalents, which is especially critical in polymerization and process scale-up.
Key point: In organoaluminum chemistry, the reagent form and standardization method are part of controllability itself—they determine whether dosing is reproducible, whether risks are manageable, and why selection should prioritize packaging form, solvent system, and concentration specifications.
7.Product Navigation Table｜Select Tables Quickly by Research Task: Organoaluminum Product Tables 1–3
Research task / experimental need | Which table to check first | Selection logic | Representative products in the table |
Olefin polymerization/copolymerization (Ziegler–Natta, metallocenes, etc.): need a co-catalyst/scavenger to “ignite” the system, consume trace water/oxygen, and make initiation more consistent | Table 1: Trialkylaluminum R₃Al | In polymerization systems, the most common “first class” of organoaluminum is R₃Al: it can both alkylate/activate the metal center and efficiently scavenge water/alcohol/oxygenated impurities. In practice, you typically need to choose the right R₃Al first before discussing catalyst platform and molecular-weight/microstructure control | TEAl (triethylaluminum), TMA (trimethylaluminum), TIBA (triisobutylaluminum), TnBA (tri-n-butylaluminum) |
The polymerization system already runs, but you want to tune activity/microstructure/impurity tolerance, or you need a stronger Lewis acid / stronger halide character co-catalyst (common in process scale-up and formulation optimization) | Table 2: Halogenated organoaluminum (R₂AlCl / RAlCl₂ / EASC) | Halogenated organoaluminum acts more like a tuning knob: within the same catalyst platform, halogenation degree and Lewis acidity can shift activation mode, ionic environment, and side-reaction profiles. When you’re solving fluctuations caused by “same platform, different batches / different impurity burdens,” benchmarking within this family is often the most effective first move | DEAC (diethylaluminum chloride), EASC (ethylaluminum sesquichloride), ethylaluminum dichloride, dimethylaluminum chloride |
Not polymerization, but Lewis-acid activation / selectivity enhancement in organic synthesis: e.g., you want a stronger but narrower-window Lewis acid to amplify stereochemical/regiochemical differences, where small deviations more readily cause side reactions/selectivity drift (Mukaiyama aldol, Diels–Alder, acetal/protecting-group activation, etc.) | Table 3: Functional organoaluminum reagents (Lewis acids / alkoxyaluminum / reductants / olefination) | The key here is function definition, not chain length or halogenation degree. You should first locate clearly purpose-defined functional reagents (bulky Lewis acids, alkoxyaluminum species, etc.), then refine the solvent/concentration window | MAD (methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide)) |
Need a milder, more tunable organoaluminum platform: for polymerization-system modification / Lewis-acidity tuning, or as a mid-strength Lewis-acid option (you don’t want overly reactive, narrower-window R₃Al / chlorinated organoaluminum) | Table 3: Functional organoaluminum reagents (alkoxyaluminum) | Alkoxyaluminum (R₂AlOR) is essentially a compromise state with tunable activity: Lewis acidity and reactivity are more controllable, making it suitable as a better-compatibility additive/modifier variable | Diethylaluminum ethoxide (and its toluene solution) |
Selective reduction: especially “stop esters/lactones at aldehydes,” controlled reduction of nitriles, etc.; requires low temperature and control of equivalents and addition rate to preserve selectivity | Table 3: Functional organoaluminum reagents (aluminum hydride reductants) | This is a classic window-driven reaction: success hinges on reductant identity + solvent (coordinating vs non-coordinating) + temperature/equivalents/addition profile. You should therefore go directly to the DIBAL/Red-Al cluster and choose more reproducible feed forms based on solvent system | DIBAL (diisobutylaluminum hydride) in various solvents, 1.0 M / 1.5 M; SBAH/Red-Al (70% in toluene) |
Within the same DIBAL system, you want to compare solvent windows: e.g., to resolve solubility/phase behavior/exotherm management/selectivity drift by comparing non-coordinating hydrocarbon phase vs coordinating THF vs other systems | Table 3: Functional organoaluminum reagents (multi-solvent DIBAL entries) | This is not “switching to a different reductant,” but rather “the same reductant exhibits different speciation/activity across solvents.” Table 3 lists DIBAL comprehensively by solvent, making it best suited for structured benchmark screening | DIBAL in hexanes / cyclohexane / heptane / toluene / THF / CH₂Cl₂ |
Carbonyl methylenation/olefination: convert aldehydes/ketones directly into alkenes (introduce =CH₂), to bypass or complement Wittig routes | Table 3: Functional organoaluminum reagents (olefination reagents) | Tebbe reagents are highly purpose-specific “specialty reagents.” Selection is driven by substrate class, functional-group tolerance, and operational window; Table 3 lets you locate them quickly | Tebbe reagent solution (0.5 M in toluene) |
You care most about reproducible feeding / safer scale-up: prefer solution forms to reduce weighing error, smooth heat release, and enable continuous addition | Table 1 or Table 2 (prioritize solution entries); for reductions/Lewis acids, use the corresponding solution entries in Table 3 | Organoaluminum reagents are generally high-risk and strongly exothermic; upon scale-up, solution forms are more favorable for metering and thermal management. Select the table by use-case first, then prioritize entries that match your solvent and concentration | TEAl 1.0 M / 25% solutions, TMA 2.0 M in various solvents, EASC 0.4 M solution, DIBAL 1.0 M multi-solvent options |
Note:
The core idea of this navigation is: first choose the table by intended function (polymerization co-catalysis/scavenging → Table 1/2; synthesis Lewis acids/reduction/olefination → Table 3), then within that table lock down a reproducible process window by matching solvent system and feed form (solution concentration / mass fraction).
Table 1｜Trialkylaluminum R₃Al (Polymerization co-catalysts / scavengers; incl. TMA/TEAl/TIBA, etc.)
Category | CAS No. | Aladdin Cat. No. | Name | Spec / Purity | Key features & applications |
Trialkylaluminum | TMA (deposition precursor / highly reactive alkylaluminum) | 75-24-1 | T107292 | Trimethylaluminum (TMA) | 2.0 M in n-hexane | Highly reactive organoaluminum: widely used as a polymerization co-catalyst/scavenger and for activation of metal platforms; also an important aluminum source for thin-film deposition. The solution form facilitates laboratory metering, reduces instantaneous exotherm and operational risk (still pyrophoric). |
Trialkylaluminum | TMA (deposition precursor / highly reactive alkylaluminum) | 75-24-1 | Trimethylaluminum (TMA) | Packaging for deposition systems | Typical ALD/CVD precursor: commonly used to deposit Al₂O₃ and other Al-based films or as an aluminum source for doping/interfacial-layer fabrication. “Deposition-system packaging” emphasizes compatibility with vapor delivery and clean feed, suitable for semiconductor/thin-film process windows. | |
Trialkylaluminum | TMA (deposition precursor / highly reactive alkylaluminum) | 75-24-1 | Trimethylaluminum (TMA) | 2.0 M in heptane | Used for polymerization co-catalysis/scavenging and metal-platform activation; can also serve as a laboratory-form aluminum source. The heptane solution supports temperature-controlled addition and matches hydrocarbon-phase systems. | |
Trialkylaluminum | TMA (deposition precursor / highly reactive alkylaluminum) | 75-24-1 | T107291 | Trimethylaluminum (TMA) | 2.0 M in toluene | Suitable when an aromatic hydrocarbon system / higher-boiling solvent window is needed for feeding and scale-up benchmarking. Used in polymerization and metal activation to scavenge trace impurities and stabilize initiation; also commonly used as a benchmark aluminum source in deposition-precursor studies. |
Trialkylaluminum | R₃Al (polymerization co-catalyst / scavenger) | 97-93-8 | T107261 | Triethylaluminum | 1.0 M in n-hexane | The most widely used trialkylaluminum: a general starting point for polymerization co-catalysis/scavenging (Ziegler–Natta, metallocene, etc.). Also used for transition-metal pre-activation and alkylation. n-Hexane solution enables low-temperature exotherm control and dropwise addition. |
Trialkylaluminum | R₃Al (polymerization co-catalyst / scavenger) | 97-93-8 | T434623 | Triethylaluminum | ≥93% | Higher-concentration / solvent-free form is better suited to polymerization and process scenarios requiring high equivalents in small volumes. As a strong reductant/scavenger, it can markedly affect initiation and side-reaction profiles; scale-up requires strict attention to thermal management, mass transfer, and safe quenching. |
Trialkylaluminum | R₃Al (polymerization co-catalyst / scavenger) | 97-93-8 | Triethylaluminum solution | 25 wt.% in toluene | TEAl solutions are often used for more temperature-controllable polymerization co-catalysis and scavenging. Toluene provides a broader solvent window, compatible with aromatic systems and higher-temperature operation; convenient for mass-fraction-based formulation and continuous addition. | |
Trialkylaluminum | R₃Al (polymerization co-catalyst / scavenger) | 102-67-0 | B299727 | Tripropylaluminum, 0.7 M in heptane | — | Typical R₃Al co-catalyst/scavenger: used in olefin polymerization and metal-catalyzed systems for alkylative activation, scavenging trace water/oxidizing impurities, and improving initiation consistency. The propyl chain is more hydrophobic and often fits hydrocarbon-phase systems; the heptane solution supports temperature control and metered addition. |
Trialkylaluminum | R₃Al (polymerization co-catalyst / scavenger) | 100-99-2 | T486499 | Triisobutylaluminum (TIBA) | — | Common co-catalyst/scavenger in polymerization: bulkier, more hydrophobic alkyl groups are often used when “milder scavenging/alkylation” and hydrocarbon-phase matching are desired. Also used to activate certain transition-metal catalyst platforms to improve initiation consistency. |
Trialkylaluminum | R₃Al (polymerization co-catalyst / scavenger) | 100-99-2 | T466124 | Triisobutylaluminum solution (TIBA) | 1.0 M in hexanes | Solution form is more favorable for exotherm control and metered addition. Commonly used for olefin polymerization co-catalysis/scavenging and catalyst pre-activation; suitable for screening and scale-up benchmarking where a reproducible feed window is needed. |
Trialkylaluminum | R₃Al (polymerization co-catalyst / scavenger) | 100-99-2 | T466515 | Triisobutylaluminum solution (TIBA) | 25 wt.% in toluene | Suitable for mass-fraction-based formulation and continuous feeding. Used for polymerization co-catalysis/scavenging and metal-platform activation; the toluene system supports higher-boiling operation and solvent-compatibility management. |
Trialkylaluminum | R₃Al (polymerization co-catalyst / scavenger) | 1116-70-7 | Tri-n-butylaluminum | 0.7 M solution in heptane | Typical trialkylaluminum: used for olefin polymerization co-catalysis/scavenging, transition-metal activation, and alkylation. The butyl chain is more hydrophobic; the heptane solution suits hydrocarbon-phase use and temperature-controlled addition. | |
Trialkylaluminum | R₃Al (polymerization co-catalyst / scavenger) | 1070-00-4 | T140701 | Trioctylaluminum solution | 25 wt.% in hexanes | Long-chain trialkylaluminum: hydrophobic and higher-boiling characteristics benefit hydrocarbon-phase systems and higher-temperature/high-viscosity operation. Often used as a “chain-length/steric” benchmark in polymerization co-catalysis/scavenging and metal-platform activation. |
Table 2｜Halogenated Organoaluminum (R₂AlCl / RAlCl₂ / EASC: polymerization co-catalysts / activators / scavengers)
Category | CAS No. | Aladdin Cat. No. | Name | Spec / Purity | Key features & applications |
Alkylaluminum chlorides | Dialkylaluminum chloride (R₂AlCl) | 96-10-6 | D130049 | Diethylaluminum chloride | 1.0 M in hexanes | Strong Lewis-acid/alkylating co-catalyst: widely used for co-catalysis and scavenging in Ziegler–Natta/metallocene olefin polymerization (captures trace water/alcohol/acid/oxygenated impurities). Also used to activate transition metals or promote certain Lewis-acid-catalyzed reactions. Solution form supports exotherm control and a manageable addition window. |
Alkylaluminum chlorides | Dialkylaluminum chloride (R₂AlCl) | 96-10-6 | D107995 | Diethylaluminum chloride | 25 wt.% in toluene | Same DEAC family: better suited for mass-fraction-based formulation/feeding. Commonly used as a co-catalyst/scavenger in polymerization and Lewis-acid activation contexts. Toluene is often chosen when a higher-boiling solvent window is needed for process/scale-up conditions (still requires inert atmosphere and proper quenching). |
Alkylaluminum chlorides | Dialkylaluminum chloride (R₂AlCl) | 96-10-6 | D107994 | Diethylaluminum chloride | 1.0 M solution in toluene | Same DEAC family: used for polymerization co-catalysis/scavenging and Lewis-acid activation. Toluene solutions can offer better controllability for low-temperature addition and exotherm management, and are often used to match compatibility with other hydrocarbon solvent systems. |
Alkylaluminum chlorides | Dialkylaluminum chloride (R₂AlCl) | 1184-58-3 | Dimethylaluminum chloride | 1.0 M in hexanes | Small-alkyl, strong Lewis acid: used for polymerization co-catalysis/scavenging and metal-platform activation; also serves as a Lewis-acid promotion/alkylation benchmark. Solution form enables precise dosing and thermal management. | |
Alkylaluminum chlorides | Alkylaluminum dichloride (RAlCl₂) | 563-43-9 | E107996 | Ethylaluminum dichloride | 25 wt.% in n-hexane | Stronger Lewis acidity / higher halogenation: commonly used for co-catalysis/activation and tuning in polymerization systems (also as a “more halogenated/more acidic” benchmark variable). Solution form supports exotherm control and dropwise addition, suitable for screening acidity/halogenation gradients. |
Alkylaluminum chlorides | EASC (alkylaluminum sesquichloride) | 12075-68-2 | Ethylaluminum sesquichloride | 0.4 M solution in toluene | Classic polymerization co-catalyst/activator: widely used in Ziegler–Natta and related olefin polymerization systems to tune activity and microstructure, while providing strong scavenging/capture of impurities. 0.4 M solution is convenient for continuous addition and exotherm control. | |
Alkylaluminum chlorides | EASC (alkylaluminum sesquichloride) | 12075-68-2 | Ethylaluminum sesquichloride | 0.4 M solution in hexane | Good compatibility with hydrocarbon-phase systems and common polymerization solvent packages; supports standardized metering and process-window control for co-catalysis/scavenging and platform activation. | |
Alkylaluminum chlorides | EASC (alkylaluminum sesquichloride) | 12075-68-2 | Ethylaluminum sesquichloride (EASC) | ≥97% | High-concentration / solvent-free form suits polymerization and process systems requiring high equivalents in small volumes. As a strong Lewis acid and scavenger, it can strongly influence initiation and side-reaction profiles; quench and workup must be built into the procedure to ensure scale-up safety and reproducibility. |
Table 3｜Functional Organoaluminum Reagents (olefination / Lewis acids / alkoxyaluminum / aluminum-hydride reductants)
Category | CAS No. | Aladdin Cat. No. | Name | Spec / Purity | Key features & applications |
Specialty olefination reagent | Tebbe methylenation | 67719-69-1 | Tebbe reagent solution | 0.5 M in toluene | Tebbe reagent is a classic Ti–Al bimetallic methylenation reagent: converts aldehydes/ketones into alkenes (introduces =CH₂) and is also used for olefination derivatives of certain esters/amides. It can serve as an alternative route for substrates that do not tolerate some Wittig conditions. Solution form facilitates dosing and temperature-controlled addition (still requires strict exclusion of moisture/oxygen). | |
Sterically demanding aryloxide-aluminum Lewis acid | MAD | 56252-55-2 | Methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) | 0.4 mol/L in toluene | A highly bulky, strong Lewis acid (often referred to as the MAD family): used to selectively activate carbonyls (aldehydes/ketones) and amplify stereochemical/regiochemical differences, commonly in “strong but picky Lewis acid” scenarios such as Mukaiyama aldol, Diels–Alder, and acetal/protecting-group activation. Solution form supports precise equivalents and low-temperature exotherm control. | |
Alkoxyaluminum | Alkylaluminum alkoxide (R₂AlOR) | 1586-92-1 | Diethylaluminum ethoxide | ≥97% | Organoaluminum bearing an alkoxy group: compared with R₃Al/chlorinated organoaluminum it is more “mild and tunable.” Often used for co-catalysis/modification in Ziegler–Natta and related systems (tuning Lewis acidity and impurity tolerance), and also as a reagent platform for Lewis-acid-promoted condensation/activation steps. | |
Alkoxyaluminum | Alkylaluminum alkoxide (R₂AlOR) | 1586-92-1 | Diethylaluminum ethoxide solution | 25 wt.% in toluene | Convenient for mass-fraction feeding and temperature-controlled addition; easier to standardize metering and manage exotherms when used for polymerization co-catalysis/modification and as a Lewis-acid activation benchmark. | |
Aluminum-hydride reductant | DIBAL (selective aldehyde formation) | 1191-15-7 | Diisobutylaluminum hydride | Reagent grade | Classic selective reductant: at low temperature, commonly used to stop reduction of esters/lactones at aldehydes or to perform controlled partial reductions; also applicable to selective transformations of nitriles (condition-dependent). Selectivity and scale-up reproducibility hinge on controlling temperature, equivalents, and addition rate. | |
Aluminum-hydride reductant | DIBAL (selective aldehyde formation) | 1191-15-7 | D107997 | Diisobutylaluminum hydride | 1.0 M in hexanes | Solution form supports low-temperature addition and heat-release management; widely used for narrow-window selective reductions such as ester → aldehyde. The non-coordinating hexane system can help maintain more controllable selectivity in some cases (still substrate/temperature dependent). |
Aluminum-hydride reductant | DIBAL (selective aldehyde formation) | 1191-15-7 | D130048 | Diisobutylaluminum hydride | 1.5 M in toluene | Higher concentration with an aromatic solvent window: suitable when smaller feed volumes or higher-boiling solvent matching is required. For selective reductions of esters/nitriles, it supports reproducible scale-up under low-temperature, rate-controlled strategies. |
Aluminum-hydride reductant | DIBAL (selective aldehyde formation) | 1191-15-7 | Diisobutylaluminum hydride solution | 1.0 M in cyclohexane | Non-coordinating, hydrophobic system often used to preserve selectivity and minimize coordination effects; supports low-temperature addition and controlled equivalents in ester → aldehyde applications, suitable for scale-up benchmarking and process comparisons. | |
Aluminum-hydride reductant | DIBAL (selective aldehyde formation) | 1191-15-7 | Diisobutylaluminum hydride solution | 1.0 M in heptane | Heptane is a common process window: supports low-temperature addition, exotherm control, and workup phase-behavior management. In selective reductions, it helps lock “temperature–equivalents–addition rate” into a reproducible range. | |
Aluminum-hydride reductant | DIBAL (selective aldehyde formation) | 1191-15-7 | D431539 | Diisobutylaluminum hydride (DIBAL) solution | 1.0 M in toluene | Toluene balances solvent latitude with controlled addition; commonly used for selective reduction and scale-up comparisons, helping keep exotherms and local high-concentration risks within a more controllable process window at low temperature. |
Aluminum-hydride reductant | DIBAL (selective aldehyde formation) | 1191-15-7 | Diisobutylaluminum hydride (DIBAL) solution | 1.0 M in THF | THF is coordinating and often improves solubility while changing activity/selectivity; suitable for poorly soluble substrates or systems needing a higher reactivity window, but requires tighter low-temperature and equivalents control to avoid over-reduction. | |
Aluminum-hydride reductant | DIBAL (selective aldehyde formation) | 1191-15-7 | Diisobutylaluminum hydride solution | 1.0 M in methylene chloride | Dichloromethane systems are convenient for low-temperature operation and solubility matching, often used when faster heat transfer and finer exotherm control are desired. Suitable as a benchmark variable to evaluate “solvent effects on selectivity/rate” (requires safety and compatibility assessment for halogenated-solvent systems). | |
Aluminum hydride / aluminate (no Al–C; reference/alternative) | SBAH/Red-Al (general reducing platform) | 22722-98-1 | Sodium bis(2-methoxyethoxy)aluminum hydride solution (SBAH) | 70 wt.% in toluene | This product contains no Al–C bond and is therefore not part of the article’s strict “organoaluminum (Al–C)” main line. However, as a widely used solution-type aluminum-hydride reducing platform in industry and laboratories, it is often listed alongside DIBAL as a benchmark/alternative (e.g., a solution alternative to LiAlH₄ or a more feed-friendly reducing system for scale-up). The toluene solution facilitates controlled addition and thermal management, making it suitable for scale-up scenarios where “controllable feeding” is critical. |
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