OxyFile #484

HPLC Study of the Cinnamic Acid Ozonation Reaction Products in 
Aqueous Medium

I. González, R. Pérez-Rey, L. A. Fernández, Ch. Baluja.

Ozone Research Center, Cuba.

Cinnamic acid was taking as a model for the study of the ozonation 
reaction  in  aqueous  medium. Water  solutions  of cinnamic acid 
(10-3 M) were ozonized at pH values of 2.5 and 7.0, T=25 oC to 
completion in a 100 mL bubbling reactor. The composition of the 
reaction mixture were followed by HPLC. Surprisingly, benzaldehyde 
was found to be formed in all cases in an almost 1:1 ratio respect 
to cinnamic acid consumed. It  means that the carbonyl moeity of 
the Criegee mechanism is only formed in the aryl side of the 
double bond, contrasting with data reported before the ozonation 
of similar compounds in organic solvents of varying polarity. An 
explanation based on the selective solvation stabilization of the 
carbonyl oxide alkyl moeity by water molecules is advanced.

Source: 2nd International Symposium on Ozone Applications
        Havana, Cuba - Mach 24-26, 1997.