Isopropyl alcohol

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Isopropyl alcohol
Image:2-propanol.png
General
Systematic name Propan-2-ol
Other names 2-Propanol, isopropanol,
Isopropyl alcohol
Molecular formula C3H8O
SMILES CC(O)C
Molar mass 60.10 g/mol
Appearance Colorless liquid
CAS number 67-63-0
Properties
Density and phase 0.78 g/cm3, liquid
Solubility in water Fully miscible
Solubility in brine Slightly soluble
In ethanol, ether
In acetone, toluene
Fully miscible
Soluble
Melting point -88 °C (185 K)
Boiling point 82 °C (355 K)
Acidity (pKa) 16.5
Viscosity 2.86 cP at 15 °C
1.77 cP at 30 °C
Dipole moment 1.66 D (gas)
Hazards
MSDS External MSDS
Main hazards Flammable
NFPA 704 Image:Nfpa h1.pngImage:Nfpa f3.pngImage:Nfpa r0.png
Flash point 12 °C
R/S statement R: 11-36-67
S: 7-16-24/25-26
RTECS number NT8050000
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Related alcohols 1-propanol,
ethanol, 2-butanol
Other compounds acetone, propylene,

diisopropyl ether,
2-bromopropane

Except where noted otherwise, data are given for
materials in their standard state (at 25°C, 100 kPa)
Infobox disclaimer and references

Isopropyl alcohol or isopropanol is a common name for propan-2-ol, a colorless, flammable chemical compound with the chemical formula CH3CHOHCH3. It is the simplest example of a secondary alcohol, where the alcohol carbon is attached to two other carbons. It is an isomer of 1-propanol.

Contents

Uses

Sterilizing pads typically contain a 60-70% solution of isopropanol in water. Isopropyl alcohol is also commonly used as a cleaner and solvent in industry. It is also used as a gasoline additive for dissolving water or ice in fuel lines. Isopropanol is the main ingredient in rubbing alcohol. It is used as a disinfectant, and is a common solvent.

Isopropanol is a major ingredient in "dry-gas" fuel additive. In significant quantities, water is a problem in fuel tanks as it separates from the gasoline. If the engine tried to combust the water instead of gasoline serious engine problems could result. The isopropanol does not remove the water from the gasoline. Rather, the isopropanol solublizes the water in the gasoline. Once soluble, the water does not pose the same risk as insoluble water.

It is also a very good cleaning agent and often used for cleaning electronic devices such as contact pins (like those on ROM cartridges), magnetic tape deck and floppy disk drive heads, the lenses of lasers in optical disc drives (e.g. CD, DVD) and removing thermal paste off CPUs.

Chemistry

Isopropyl alcohol forms an azeotrope with water at 68.33% alcohol. It is impossible to dehydrate isopropanol further using non-azeotropic distillation. For this reason, more expensive means, such as using a drying agent, are necessary for production of 100% isopropyl alcohol.

Being a secondary alcohol, isopropanol can be oxidised to acetone. This can be achieved using oxidising agents such as chromic acid, or by dehydrogenation of isopropanol over a heated copper catalyst:

(CH3)2CH-OH → (CH3)2C=O + H2

Isopropanol may be converted to 2-bromopropane using phosphorus tribromide, or dehydrated to propylene by heating with sulfuric acid. With sodium hydroxide and a halogen, or with sodium hypochlorite, it undergoes the haloform reaction.

Isopropanol is often used as a hydride source in the Meerwein-Ponndorf-Verley reduction.

Like most alcohols, isopropyl alcohol reacts with active metals such as potassium to form alkoxides. The reaction with aluminium (initiated by a trace of mercury) is used to prepare the catalyst aluminium isopropoxide.

Isopropanol has a maximal absorbance spectra at 204 nm.

Safety

Isopropyl alcohol is flammable. It should be kept away from heat and open flame.

Isopropyl alcohol is oxidized by the liver into Acetone. Symptoms of isopropyl alcohol poisoning include flushing, headache, dizziness, CNS depression, nausea, vomiting, anesthesia, and coma. Use in well-ventilated areas and use protective gloves while using. Poisoning can occur from ingestion, inhalation, or absorption.

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