Isopropanol

Isopropanol

Isopropanol sample and its original bottle.
Names
IUPAC name 2-Propanol
Systematic IUPAC name Isopropanol
Other names Dimethyl carbinol; IPA; iPrOH; Propan-2-ol; Rubbing alcohol; s-Propanol; sec-Propyl alcohol
Identifiers
Jmol-3D images	Image
SMILES CC(O)C
Properties
Chemical formula	C3H8O
Molar mass	60.10 g/mol
Appearance	Colorless volatile liquid
Odor	Alcoholic, weak acetone-like
Density	0.786 g/cm3 (at 20 °C)
Melting point	−89 °C (−128 °F; 184 K)
Boiling point	82.6 °C (180.7 °F; 355.8 K)
Solubility in water	Miscible
Solubility	Miscible with methanol, ethanol, benzene Insoluble in saline solution
Acidity (pKa)	16.5
Hazards
Safety data sheet	ScienceLab
Flash point	Open cup: 11.7 °C (53.1 °F; 284.8 K) Closed cup: 13 °C (55 °F)
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	12800 mg/kg (dermal, rabbit) 3600 mg/kg (oral, mouse) 5045 mg/kg (oral, rat) 6410 mg/kg (oral, rabbit)
LC50 (Median concentration)	53000 mg/m3 (inhalation, mouse) 12,000 ppm (rat, 8 hr)
Related compounds
Related compounds	Ethanol Propanol Butanol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Isopropanol, or isopropyl alcohol, is a secondary alcohol. It provides the familiar smell of rubbing alcohol, where it is frequently used although this may be ethanol. Isopropanol is the largest carbon chain alcohol to be miscible with water and is a common OTC solvent.

Properties

Chemical

Isopropanol is a generally nonreactive (inorganically speaking) alcohol. It can be dehydrated, and is a common reagent in organic chemistry.

Anhydrous isopropanol is used to neutralise small quantities of sodium or potassium metal, as the reaction with the alcohol is mild compared to with water and removes any reactive metal that may pose a danger if left in the lab. This property allows for the production of metal isopropoxides.

A violent runaway reaction happens when isopropanol comes into contact with a nitration bath. Toxic nitrogen dioxide is produced in a rapid reaction as the isopropanol is not nitrated but oxidised by the acids.

Isopropanol can be reacted with nitrous acid to for isopropyl nitrite and with mixed acids to form isopropyl nitrate.

Physical

Isopropanol is a clear, colorless liquid miscible in water. It's smell is described as closer to acetone than other short chain alcohols like ethanol. It burns on contact with cuts (like ethanol) and it's widely used as an antiseptic. It is a good, cheap solvent.

Availability

Isopropanol is available in concentrations anywhere from 60% to 99% (the rest being water) for a variety of applications, often cleaning electronics or sold as 'rubbing alcohol'. The most common concentrations are 70% and 91%. These store-bought solutions can be salted out up to a concentration of about 91% using sodium chloride, and nearly all water can be separated by salting out with sodium hydroxide, though this may inadvertently contaminate the isopropanol and produce sodium isopropoxide. Dry isopropanol has the potential to form explosive peroxides when distilled, so it is highly recommended that these distillations are carefully monitored if done at all.

Preparation

Isopropanol is produced by hydrogenation of acetone over a nickel catalyst. It can also be obtained by hydrolysing esters containing an isopropyl group.

Projects

• Chloroform synthesis
• Isopropyl chloride
• Isopropyl nitrite
• Isopropyl esters
• Diisopropyl ether
• Isopropanol peroxide (EXTREMELY DANGEROUS!!!)

Handling

Safety

Isopropanol is flammable. It has low toxicity and it's much less toxic than methanol or ethylene glycol. Vapours of dry isopropanol can potentially be explosive.

Storage

Isopropanol should be stored in closed bottles, away from any oxidants and fire sources. As it is prone to forming peroxides over long periods of time, a small amount of antioxidant should be added, unless it already has. OTC isopropanol already has antioxidants in its content.

Disposal

Isopropanol can be safely burned. Old bottles that have been exposed to air should be checked for any peroxides and if there are any, they should be neutralized if safely possible.

References

Relevant Sciencemadness threads

• High Purity Isopropanol
• drying isopropanol
• Isopropyl Alcohol (2-propanol) Peroxides