Advices For Studying Organic Chemistry

Step 1

(CH 2 ) 7 CO 2 R'

H H

CH 3 (CH 2 ) 4

HH

C

H H

RO

(CH 2 ) 7 CO 2 R'

H H

CH 3 (CH 2 ) 4

HH

C

H

(CH 2 ) 7 CO 2 R'

H H

CH 3 (CH 2 ) 4

HH

C

H

Chain initiation

− ROH

OO

Step 2 Chain Propagation

(CH 2 ) 7 CO 2 R'

H H

CH 3 (CH 2 ) 4

HH

C

H

(CH 2 ) 7 CO 2 R'

H H

CH 3 (CHH 2 ) 4

H

C

H

O O

(CH 2 ) 7 CO 2 R'

H H

H 2 ) 4

H

C

H

O

CH 3 (C

H

O

Step 3 Chain Propagation

(CH 2 ) 7 CO 2 R'

H H

CH 3 (CH 2 ) 4

H

H

C

H

HO O

Another radical

+ Lin

en abstraction from another A hydroperoxide

Lin H

Hydrog

molecular of the linoleic ester

Figure 10.7 Autoxidation of a linoleic acid ester. In step 1 the reaction is initiated
by the attack of a radical on one of the hydrogen atoms of the –CH 2 –
group between the two double bonds; this hydrogen abstraction
produces a radical that is a resonance hybrid. In step 2 this radical
reacts with oxygen in the first of two chain-propagating steps to
produce an oxygen-containing radical, which in step 3 can abstract a
hydrogen from another molecule of the linoleic ester (Lin–H). The
result of this second chain-propagating step is the formation of a
hydroperoxide and a radical (Lin•) that can bring about a repetition of
step 2.