Fatty alcohols are aliphatic alcohols with chain lengths between C6 and C22:
CH3(CH2)NCH2OH(n= 4-20)
They are predominantly linear and monohydric, and can be saturated or have one or more double bonds. Alcohols with a carbon chain lengthabove C22 are referred to as wax alcohols. Diols whose chain length exceeds C8 are regarded as substituted fatty alcohols. The character of the fatty alcohols (primary or secondary, linear or branched-chain, saturated or unsaturated) is determined by the manufacturing process and the raw materials used. Natural products, such as fats, oils, and waxes, and the Ziegler alcohol process provide linear, primary, and even-numbered alcohols; those obtained from natural sources may be unsaturated. In contrast, the oxo process yields 20 – 60 % branched fatty alcohols, and also some odd-numbered ones. Guerbet dimerization results in a-branched, primary alcohols, whereas Bashkirov oxidation yields secondary alcohols.
Depending on the raw materials used, fatty alcohols are classified as natural or synthetic. Natural fatty alcohols are based on renewable resources such as fats, oils, and waxes of plant or animal origin, whereas synthetic fatty alcohols are produced from petrochemicals such as olefins and paraffins. Up to 1930, when catalytic highpressure hydrogenation was developed ADKINS and FOLKER [7], NORMAN [8], SCHRAUTH [9], and SCHMIDT [10], the manufacture of fatty alcohols was based almost exclusively on the splitting of sperm oil. By 1962, the world production capacity from natural raw materials had grown to ca. 200 000 t/a. New processes utilizing petrochemical raw materials, e.g., the Ziegler alcohol process, the SHOP process, the oxo process, and the construction of additional plants for highpressure hydrogenation of natural raw materials, allowed a further increase. In 2005, the world nameplate production capacity of fatty alcohols was estimated to be 2.5 106 t/a, being nearly equally based on natural and petrochemical feedstocks. This ratio will change because 600 000 – 700 000 t/a of additional production capacity based on natural feedstocks will come on stream by 2008. Production and consumption were estimated to amount to only 80 % or less of capacity. Fatty alcohols and their derivatives are used in polymers, surfactants, oil additives, and cosmetics and have many specialty uses.
