Aliphatic Compounds

ALIPHATIC COMPOUNDS (from Greek aleiphar - oil), fatty, acyclic compounds - a class of organic compounds whose carbon atoms are linked to each other in the form of open, extended chains. In view of the fact that the main substance of this series is methane (see), from which all A. s. can be produced, they are also called methane compounds. Depending on the form of the carbon skeleton, A. s. of normal structure with one carbon chain (1) and A. s. with branched chains (2) are distinguished. According to the criterion of saturation, i.e., the ability of a given substance to attach other atoms or groups of atoms, A. s. are divided into saturated and unsaturated. The latter are characterized by the presence in the molecule of so-called multiple bonds, for example, a double or ethylene bond, schematically depicted by two dashes (for example, ethylene CH₂=CH₂, propylene CH₂=CH-CH₂, etc.), or triple, as in acetylene CH≡CH. Unsaturated compounds have a relatively large reserve of free energy. Aliphatic compounds are extremely widespread in nature (fats, carbohydrates, etc.). Many substances of mineral origin, such as Pennsylvania petroleum (Baku petroleum consists of cyclic hydrocarbons), paraffin, ozokerite, are mixtures of various hydrocarbons of the aliphatic series.