Fatty acid, fragmentation mechanism

Figure 5. Proposed mechanism for the directed oxidation by tocopherol-type antioxidants for n-3 fatty acid fragments leading to the formation of Cg compounds.

Ecostar (St. Lawrence Starch Company). This product associates PE with a mixture of starch and auto-oxidant unsaturated fatty acids. The global content of starch is between 6 and 15%. The degradation process then follows two mechanisms in the first, the starch is fragmented, then assimilated by microorganisms, whereas in the second, the interaction between the auto-oxidants and the metallic complexes from soil or water gives peroxides that attack the synthetic polymer chains. 

Figu re 14.7 Mechanism of acid-catalyzed transesterification R1 -glyceride fragment, R2-fatty-acid carbon chain. 

The 1,4-elimination mechanism of H2 occurring along the fatty acid chain in order to yield fragments corresponding to the loss of an alkene. 

Another mechanism for the removal of surface films was discovered by Wheeler (1972), who found that fatty acid films on seawater collapsed to form particles when exposed to near-ultraviolet radiation. The results indicated that there was an introduction of hydroperoxide groups into the parent fatty acid molecule with resultant polymerization of the products. Instead of polymerization, Timmons (1962) found that the constituents of plankton oil films were converted to smaller and more soluble fragments when exposed to artificial sunlight. Photochemically initiated solubilization appears to be a process common to some constituents of crude oil and fuel oil films as well, with low molecular weight acids, sulfoxides, and peroxides comprising some of the product soluble fraction (Burwood and Speers, 1974 Hansen, 1975 Larson et al., 1977). The rate of photo-oxidation of films of various fractions of crude oil spread on water was greatly increased... 

D. J. Harvey, A new charge-associated mechanism to account for the production of fragment ions in the high-energy CID spectra of fatty acids, J. Am. Soc. Mass Spectrom. 16, 280-290 (2005). 

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