Drying oils, conjugation

Conjugated-diene butyl, 4 436—431 Conjugated drying oils, 9 148 Conjugated hemoglobin, 4 122-124 Conjugated linoleic acid (CLA), 10 829 17 664-665... 

Composition and Analysis. Naturally occurring drying oils are triglycerides. The reactivity of the oils results fiotn the presence of esters of fatty acids with two or mure nonconjugated double bonds separated by single methylene groups. -CH=CHCHiCH=CH hose with two or more conjugated double bonds. Typical compositions of some of the more important oils are listed in Table I... 

Dehydration of castor oil and of castor acids gives products enriched in diene acids, some with conjugated unsaturation. These products are valuable alternatives to drying oils such as tung oil. 

Eleostearic (conjugated) Octadeca-9c, 111,13t-trienoic Tung, Bitter Melon Drying oil... 

Air-drying oils or polyester resins (single component) Conjugated double bonds and other unsaturation sites Air oxidation, peroxide formation, and coupling between polymer chains (free radical) 5 > z D O 70 C 00 m 70... 

Dehydration of unsaturated alcohols is important only in special cases, since such starting materials are difficultly accessible. According to Scheiber,104 octadecadienoic acid can be prepared by dehydration of ricinoleic acid owing to its conjugated double bonds it is a valuable starting material for synthetic drying oils of tung oil type. 

To improve the drying properties of nonconjugated drying oils (linseed, perilla, etc.) so-called activation processes have been developed, in which the double bonds are shifted into the conjugated positions. Thus, the oils are rendered more active with respect to polymerization and oxidation, i.e., to drying. 

The course of the activation process can be followed by measuring the diene value (6), ultraviolet spectra (7), specific refraction, and iodine value 8). This last principle allows an easy detection of the conjugation reactions in connection with polymerization processed of drying oils under different conditions, because of the considerable increase of the specific refraction during conjugation. 

Polymerization of drying oils in the presence of sulfur dioxide was first described by Waterman and Van Vlodrop 16). The action of the catalyst is based mainly on its conjugating properties. 

Gaboon, E.B. T.J. Carlson K.G. Ripp B.J. Schweiger G.A. Cook S.E. Hall A.J. Kinney. Biosynthetic origin of conjugated double bonds Production of fatty acid components of high-value drying oils in transgenic soybean embryos. P. Natl Acad. Sci. USA 1999, 96, 12935—12940. 

Oyman, Z.O. W. Ming R. Van Der Linde. Oxidation of drying oils containing non-conjugated and conjugated double bonds catalyzed by a cobalt catalyst. Prog. Org. Coat. 2005, 54, 198-204. 

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