Drying oils unsaturated fatty acids

Cobalt in Driers for Paints, Inks, and Varnishes. The cobalt soaps, eg, the oleate, naphthenate, resinate, Hnoleate, ethyUiexanoate, synthetic tertiary neodecanoate, and tall oils, are used to accelerate the natural drying process of unsaturated oils such as linseed oil and soybean oil. These oils are esters of unsaturated fatty acids and contain acids such as oleic, linoleic, and eleostearic. On exposure to air for several days a film of the acids convert from Hquid to soHd form by oxidative polymeri2ation. The incorporation of oil-soluble cobalt salts effects this drying process in hours instead of days. Soaps of manganese, lead, cerium, and vanadium are also used as driers, but none are as effective as cobalt (see Drying). 

The lipid of morama beans is mainly ( 75%) unsaturated fatty acids, with the principal fatty acid being oleic acid (43%). The beans furthermore contain linoleic (22%) and palmitic acid (13%) as well as stearic, arachidic, linolenic, arachidonic, erucic, behenic, myristic, palmitoleic, and gadoleic acid in lower concentrations (Bousquet, 1982 Bower et ah, 1988 Engelter and Wehmeyer, 1970 Francis and Campbell, 2003 Ketshajwang et ah, 1998 Mitei et ah, 2008). The fatty acid composition resembles that of olive oil (Mitei et ah, 2008). A literature review of the fatty acid composition of morama beans is given in Table 5.3. Less than 5% of the fatty acids are present as free acids (Bower et ah, 1988 Dubois et ah, 1995), which means that the activity of lipases is negligible in dry morama beans. 

For the structural analysis of cyclic fatty acid derivatives (polymerized drying oils, copolymerization products of fatty oils with various hydrocarbons), in principle the same graphical methods can be developed as have been described for the investigation of hydrocarbon mixtures. However, the construction of useful graphical representations is hampered by the fact that reliable data on physical constants are restricted to the normal saturated fatty acids and their methyl and ethyl esters the synthesis of pure unsaturated fatty acids is already extremely difficult, to say nothing of more complicated cyclic or branched compounds. 

A peach coloured oil with a delicate nutty aroma. Emollient and highly nourishing it is particularly suited to dry and mature skins. It is unusual in that it is comparatively high in the unsaturated fatty acids oleic acid (55-67%), pal-mitoleic acid (18-25%), palmitic acid (7.0-9.5%), stearic acid (2.0-5.5%) and myristic acid (0.6-1.6%). It has good keeping properties, as it is quite resistant to oxidation. There are no reported irritation or allergy reactions in skin testing. 

Jojoba (Simmondsia chincnsis) This is not actually an oil but a liquid wax. It is good for cosmetic use with moisturizing properties and ideal for dry skin and conditions like eczema and psoriasis. It is similar chemically to sebum and able to dissolve it. The oil keeps well owing to a stable molecular structure and analysis shows both saturated and unsaturated fatty acids, with eicosenoic (71%), oleic (14%), stearic (10%) and palmitic (1.5%). The presence of a compound called myristic acid is thought to confer anti-inflammatory properties. 

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