Oxygen-Containing Compounds

Organic compounds that include oxygen in addition to carbon and hydrogen include alcohols,
ethers, carbohydrates, and carbonyl compounds such as aldehydes, ketones, esters, and carboxylic
acids.

ALCOHOLS

Alcohols contain the functional group –OH, sometimes called the hydroxyl group. Ethanol, for
example, can be considered a derivative of ethane, with the hydroxyl group in the place of a
hydrogen atom:

Because oxygen has such high electronegativity, the hydrogen attached to it (the hydrogen of the
hydroxyl group) can participate in hydrogen bonding.

The diagram below illustrates how this can occur; the R represents the organic group to which the
alcohol functionality is attached (e.g., for ethanol, R = CH 3 CH 2 –):

Hydrogen bonding is a strong intermolecular attractive force, and this causes alcohols to have
boiling points that are significantly higher than those of the analogous hydrocarbons. The boiling
point of propane (CH 3 CH 2 CH 3 ), for example, is −42.1°C, while that of propanol (CH 3 CH 2 CH 2 OH) is
97.4°C. Ethylene glycol, which is ethane with two hydroxyl groups attached (one to each carbon