Isopropyl alcohol in the context of "International Union of Pure and Applied Chemistry"

In chemistry, volatility is a material quality which describes how readily a substance vaporizes. At a given temperature and pressure, a substance with high volatility is more likely to exist as a vapour, while a substance with low volatility is more likely to be a liquid or solid. Volatility can also describe the tendency of a vapor to condense into a liquid or solid; less volatile substances will more readily condense from a vapor than highly volatile ones. Differences in volatility can be observed by comparing how fast substances within a group evaporate (or sublimate in the case of solids) when exposed to the atmosphere. A highly volatile substance such as rubbing alcohol (isopropyl alcohol) will quickly evaporate, while a substance with low volatility such as vegetable oil will remain condensed. In general, solids are much less volatile than liquids, but there are some exceptions. Solids that sublimate (change directly from solid to vapor) such as dry ice (solid carbon dioxide) or iodine can vaporize at a similar rate as some liquids under standard conditions.

There are two isomers of propanol.

• 1-Propanol, n-propanol, or propan-1-ol: CH₃CH₂CH₂OH, the most common meaning
• 2-Propanol, isopropyl alcohol, isopropanol, or propan-2-ol: (CH₃)₂CHOH

Rubbing alcohol, known as surgical spirit in the British Pharmacopoeia, refers to a group of denatured alcohol solutions commonly used as topical disinfectant. In addition to its medical applications, rubbing alcohol is employed in various industrial and household contexts. These solutions are primarily composed of either isopropyl alcohol (isopropanol) or ethanol, with isopropyl alcohol being the more widely available formulation.

The United States Pharmacopeia (USP) defines "isopropyl rubbing alcohol USP" as a solution containing approximately 70% alcohol by volume of pure isopropanol, while "rubbing alcohol USP" refers to a solution containing approximately 70% by volume of denatured ethanol. In Ireland and the United Kingdom, the comparable product is "surgical spirit B.P.", defined by the British Pharmacopoeia as containing 95% methylated spirit, 2.5% castor oil, 2% diethyl phthalate, and 0.5% methyl salicylate. Known alternatively as "wintergreen oil", methyl salicylate is also a common additive in North American rubbing alcohol products.

Denatured alcohol, also known as methylated spirits, metho, or meths in Australia, Ireland, New Zealand, South Africa, and the United Kingdom, and as denatured rectified spirit, is ethanol that has additives to make it poisonous, bad-tasting, foul-smelling, or nauseating to discourage its recreational consumption. It is sometimes dyed so that it can be identified visually. Pyridine and methanol, each and together, make denatured alcohol poisonous; denatonium makes it bitter.

Denatured alcohol is used as a solvent and as fuel for alcohol burners and camping stoves. Because of the diversity of industrial uses for denatured alcohol, hundreds of additives and denaturing methods have been used. The main additive usually is 10% methanol (methyl alcohol), hence the name methylated spirits. Other common additives include isopropyl alcohol, acetone, methyl ethyl ketone, and methyl isobutyl ketone.