Aluminum isopropoxide
| Aluminum isopropoxide | |
|---|---|
| Aluminum isopropoxide | |
| General | |
| Systematic name | Aluminum Isopropoxide |
| Other names | triisopropoxyaluminum; 2-Propanol, aluminum salt; AIP; |
| Molecular formula | Al(O(CH3)CHCH3)3 |
| Molar mass | 204.25 g/mol |
| Appearance | white solid |
| CAS number | [555-31-7] |
| Properties | |
| Density and phase | 1.03 g/cm3, solid |
| Solubility in water | insoluble |
| in methanol | soluble |
| Melting point | 130 °C (303 K) |
| Boiling point | decomposes |
| Structure | |
| Coordination geometry | ? |
| Crystal structure | monoclinic |
| Dipole moment | ? D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | toxic to lungs, mucous membranes |
| NFPA 704 |   
|
| Flash point | n/a |
| R/S statement | R: 38,41 S: 7/8, 24/25, 43 use dry chemical powder |
| RTECS number | BD0975000 |
| Supplementary data page | |
| Structure & properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references | |
Aluminum isopropoxide (Al[OCH(CH3)2)]3) is a metal-organic compound of aluminum that is useful in organic chemistry. Aluminum isopropoxide was first used as a reducing agent by Meerwein and Schmeidt in the Meerwein–Ponndorf–Verley (MPV) reduction in 1925.[1]
In 1937, Oppenauer used aluminum isopropoxide as an oxidizing agent in a reaction that was essentially the reverse of the MPV reduction.[2] This reaction is known as the Oppenauer Oxidation.
Preparation
The most common way of preparing aluminum isopropoxide was published in 1936 by Young, Hartung, and Crossley.[3] Their procedure entails heating a mixture of 100 g of aluminum wire, 1200 mL of Isopropyl alcohol, and 5 g of mercuric chloride at reflux for seven hours. An catalytic amount of iodine is sometimes now used to initiate the reaction, which can be quite vigorous. Young et al. achieved an 85-90% yield, after purification by distillation at 140-150 °C (5 mm Hg).
Reactions
In a MPV reduction, ketones and aldehydes are reduced to alcohols concomitant with the formation of acetone. This reduction relies on an equilibrium process, hence it produces the thermodynamic product.
Conversely, in the Oppenauer Oxidation, 2° alcohols are converted to ketones[4] while homoallylic alcohols are converted to α,β-unsaturated carbonyls.
References
- ^ Meerwein, H.; Schmidt, R. Justus Liebigs Ann. Chem. 1925, 39, 221.
- ^ Oppenauer, R. V., Recl. Trav. Chim. Pays-Bas, 56, 137, 1937.
- ^ Young, W.; Hartung, W.; Crossley, F. "Reduction of Aldehydes with Aluminum Isopropoxide" Journal of the American Chemical Society, 58, page 100-2, 1936.
- ^ Eastham, J. F.; Teranishi, R. "Δ4-Cholesten-3-one" Organic Syntheses, Coll. Vol. 4, p.192 (1963); Vol. 35, p.39 (1955).