Abstract

Branched-chain acids contain at least one branching alkyl group, which causes different physical, and in some cases different chemical, properties than their corresponding straight-chain isomers. For example, stearic acid has a melting point of about 69°C, whereas isostearic acid has a melting point of about 5°C.

Manufacturing procedures for most branched-chain acids are well known. Oxo process acids are manufactured from branched-chain olefins using hydroformylation followed by oxidation. Neo acids are prepared from selected olefins using carbon monoxide. 2-Ethylhexanoic acid is manufactured by an aldol condensation of butyraldehyde followed by an oxidation. Isostearic acid is produced from the monomeric acids obtained in the dimerization of unsaturated C₁₈ fatty acids.

Cobalt and manganese salts of 2-ethylhexanoic acid are used in the formulation of greases and lubricants. Derivatives of isostearic acid have been used as pour point depressants in two-cycle engine oils, as textile lubricants, and in cosmetics. The hazards of handling branched-chain acids are similar to those encountered with other aliphatic acids of the same molecular weight.