The reaction proceedsas follows: O2

The reaction proceeds
as follows: O2þ2H
þ
þ3Fe
2þ/OHþOH

þ3Fe
3þ
(Angelo,
1992). A small number of free radicals can trigger the
propagation to produce lipid peroxide (Young and
McEneny, 2001). In the final stage, the ferric, released from
cement, would react with lipid peroxide (RCOOH) as
Fe
3þ
þRCOOH/Fe
2þ
þH
þ
þRCOO. The production of H
þ
would accelerate the release of calcium hydroxide from concrete and cause the pH to drop in the solution. Since there are
two double bonds in linoleic acid and one double bond in oleic
acid, twice the RCOOH should be produced leading to twice H
þ
produced and twice calcium released in linoleic than in oleic.
This difference in unsaturation would explain why the pH
dropped several days earlier in linoleic samples compared to
the oleic samples