Summary
Highlights
Organic compounds contain carbon. Carbon's atomic structure allows it to form four covalent bonds with other elements and carbon atoms. It can form single, double, and triple bonds, leading to diverse structures like short, long, straight, and branched chains.
Alcohols are organic compounds used as antiseptics, disinfectants, cleaning agents, in liquors, and as fuel. An alcohol molecule consists of an alkyl group and a hydroxyl group, as exemplified by ethanol.
The boiling points of alcohols increase with more carbon atoms due to stronger intermolecular attractions (hydrogen bonding). Alcohols are soluble in water because the hydroxyl group forms hydrogen bonds with water. Smaller alcohols are very soluble, but solubility decreases as the hydrocarbon chain lengthens. Viscosity increases with molecular size due to stronger intermolecular forces. Flammability decreases as molecular size and mass increase because more covalent bonds need to be broken for combustion.
Aldehydes and ketones contain a carbonyl group. In aldehydes, the carbonyl group is at the end of the molecule, with one hydrogen atom attached. In ketones, the carbonyl group is located anywhere between two terminal ends, with two hydrocarbon groups attached and no hydrogen atom on the carbonyl group. Formaldehyde is the simplest aldehyde, and acetone is the simplest ketone.
Methanol (gas) has a boiling point of -21°C, while ethanol (liquid) boils at 21°C. Boiling points rise as molecules get bigger. Lower members of aldehydes and ketones are miscible with water due to hydrogen bonding, but solubility decreases as the alkyl chain lengthens. All aldehydes and ketones are soluble in organic solvents. Lower aldehydes have sharp, pungent odors, which become more fragrant as the molecule size increases.
Formaldehyde (formalin) is used for preserving tissue and embalming. Acetaldehyde occurs naturally and is used in acetic acid production. Propionaldehyde is a flavoring agent. Dimethyl ketone (acetone) is a solvent for lacquers and a paint remover. Butanone (methyl ethyl ketone) is an industrial solvent used in plastics and textiles. Cyclohexanone is used in nylon production.
An alcohol molecule has an alkyl and a hydroxyl group. Aldehydes and ketones contain a carbonyl group; in aldehydes, it's at the terminal end, and in ketones, it's between the terminal ends.
Methanol is used as fuel and a polar organic solvent. Ethanol is produced through fermentation and used as motor fuel. Isopropyl alcohol is an industrial solvent and rubbing alcohol. Ethylene glycol is used in antifreeze, hydraulic fluids, and printing inks. Glycerol is a byproduct of soap manufacturing, used in explosives, as a vasodilator, solvent, and moisturizer.