Alifático

Alifático is a term used in organic chemistry to describe compounds that contain carbon atoms arranged in a straight or branched chain, or in a non-aromatic ring. These compounds are contrasted with aromatic compounds, which have a cyclic structure with delocalized pi electrons. Aliphatic hydrocarbons, the simplest aliphatic compounds, are composed solely of hydrogen and carbon atoms. They can be saturated, meaning all carbon-carbon bonds are single bonds, such as alkanes (e.g., methane, ethane, propane). Alternatively, they can be unsaturated, containing at least one carbon-carbon double or triple bond, such as alkenes (e.g., ethene, propene) and alkynes (e.g., ethyne, propyne).

The term "aliphatic" originates from the Greek word "aleiphar," meaning fat or oil, reflecting the fatty acid origins of many early discovered aliphatic compounds. Beyond hydrocarbons, aliphatic compounds can also include functional groups such as alcohols, aldehydes, ketones, carboxylic acids, and amines. These functional groups determine the chemical properties and reactivity of the molecule. Aliphatic compounds are fundamental building blocks in organic chemistry and are found in a vast array of natural and synthetic substances, including fuels, plastics, solvents, and biological molecules. Their structures range from simple molecules with a few carbon atoms to very large polymers.