Aluminium isopropoxide

Aluminium isopropoxide

Names
IUPAC name Aluminium isopropoxide
Other names 2-Propanol aluminium salt AIP Aluminium isopropanolate Aluminum propan-2-olate Aluminium sec-propanolate Aluminium triisopropoxide Triisopropoxyaluminium
Properties
Chemical formula	C9H21O3Al
Molar mass	204.25 g/mol
Appearance	Colorless solid
Odor	Odorless
Density	1.035 g/cm3
Melting point	119 °C (246 °F; 392 K)
Boiling point	135 °C (10 mm Hg) 131 °C (7.5 mm Hg) 125.5 °C (5.5 mm Hg) 113 °C (2.5 mm Hg) 106 °C (1.5 mm Hg) 94 °C (0.5 mm Hg)
Solubility in water	Hydrolyzes
Solubility	Reacts with carboxylic acids Soluble in benzene, carbon disulfide, CCl4, chloroform, ethanol, THF, toluene Moderate soluble in isopropanol Insoluble
Vapor pressure	1.33-47.33 mmHg (at 119 - 173.9 °C)
Hazards
Safety data sheet	Sigma-Aldrich
Flash point	16 °C
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	11,300 mg/kg (rat oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Aluminium isopropoxide or aluminium triisopropoxide is a chemical compound, a salt of isopropanol with aluminium. It is widely used as a reducing agent for reducing ketones and aldehydes to their corresponding alcohols. It has the chemical formula C₉H₂₁O₃Al. The general formula used for the compound is Al(O-i-Pr)₃, where i-Pr is the isopropyl group (CH(CH₃)₂).

Properties

Chemical

Aluminium isopropoxide readily hydrolyzes in water to isopropanol and aluminium(III) hydroxide.

Physical

Aluminium isopropoxide is a colorless solid, slightly soluble in alcohols, but more soluble in THF and carbon disulfide. It has the tendency to supercool.

The structure of this compound is complex, possibly time-dependent, and may depend on solvent.

Availability

Aluminium isopropoxide is sold by chemical suppliers. There doesn't appear to be any sellers on eBay or Amazon.

Preparation

Aluminium isopropoxide can be prepared by reacting a mixture or aluminium metal with anhydrous isopropanol, in the presence of a catalyst, such as mercury(II) chloride. The resulting aluminium triisopropoxide is extracted from the reaction mass via factional distillation under vacuum. Some mercury may distill and condense in the resulting isopropoxide, though it can be removed with a syringe. For better purity, aluminium triisopropoxide should be recrystallized, in a dry environment. NileRed made a video on how to make this compound.

It is believed that a gallium-aluminium alloy can be used instead of the aluminium + HgCl₂ route.

Projects

• Reduce ketones and aldehydes to their respective alcohols and viceversa

Handling

Safety

Aluminium isopropoxide is water-sensitive and contact with skin should be avoided. Wear gloves and protection goggles when handling the compound.

Storage

Aluminium isopropoxide should be stored in air-tight containers or in a desiccator.

Disposal

Can be destroyed by burning it outside. Hydrolysis gives isopropanol, which is non-toxic but flammable.

References

Relevant Sciencemadness threads

• Preparation of solid aluminium isopropoxide
• Simple(er)Aluminum Isopropoxide prep experiment for later this week.