and can therefore be easily abstracted, resulting in radical chain initiation and thus
autoxidation.[27, 38, 39] Abstraction of one of the bis-allylic hydrogen atoms results in the
formation of a radical species. This radical species is stabilised by delocalisation due to
the local pentanediene structure. Molecular oxygen reacts extremely rapid with this
pentanedienyl radical species to form a peroxy radical which has the double bonds
dominantly conjugated, since this is the most stable structure.[7] The peroxyl radical can
then participate in a host of reactions, as was outlined in section 1.2.1 and scheme 1.1, but
in the early stages of autoxidation the dominant reaction will be to abstract a hydrogen
atom from another lipid molecule to form a hydroperoxide and propagate the radical
chain (reaction 8 in scheme 1.1). Scheme 1.4 shows the initial autoxidation reactions for a
fatty acid pentanediene substructure, forming a hydroperoxide. Figure 1.3 shows the total
time course of fatty acid autoxidation: the fatty acid concentration will rapidly decrease as
hydroperoxides are formed. The hydroperoxide concentration will go through a maximum
when hydroperoxide formation is surpassed by hydroperoxide decomposition.
and can therefore be easily abstracted, resulting in radical chain initiation and thus
autoxidation.[27, 38, 39] Abstraction of one of the bis-allylic hydrogen atoms results in the
formation of a radical species. This radical species is stabilised by delocalisation due to
the local pentanediene structure. Molecular oxygen reacts extremely rapid with this
pentanedienyl radical species to form a peroxy radical which has the double bonds
dominantly conjugated, since this is the most stable structure.[7] The peroxyl radical can
then participate in a host of reactions, as was outlined in section 1.2.1 and scheme 1.1, but
in the early stages of autoxidation the dominant reaction will be to abstract a hydrogen
atom from another lipid molecule to form a hydroperoxide and propagate the radical
chain (reaction 8 in scheme 1.1). Scheme 1.4 shows the initial autoxidation reactions for a
fatty acid pentanediene substructure, forming a hydroperoxide. Figure 1.3 shows the total
time course of fatty acid autoxidation: the fatty acid concentration will rapidly decrease as
hydroperoxides are formed. The hydroperoxide concentration will go through a maximum
when hydroperoxide formation is surpassed by hydroperoxide decomposition.
การแปล กรุณารอสักครู่..