OxyFile #478

Analysis of Ozonides and Peroxidic Compounds from Methyl Oleate 
Ozonation

O. E. Ledea, J. Moleiro, M. Diaz, D. Jardines, A. Rosado(1), 
T. Correa(1).

Ozone Research Center, Cuba.
1 - National Center for Scientific Research, Cuba. 

Methyl oleate ozonation, in hexane (non participating solvent) at 
a concentration of 0.3 M and in presence of protic substances, 
such as ethanol and water, was carried out. A bubbling reactor at 
25 C, with an ozone dose of 50 mg per gram of sample was used. 
Proton Nuclear Magnetic Resonance (H1-NMR) and Gas 
Chromatography/Mass Spectrometry (GC/MS) techniques, in order to 
identify the reaction products in all the studied conditions, were 
used. During ozonation of methyl oleate in hexane, the 
corresponding ozonides/oligomeres were identified. It was design a 
simple procedure for GC/MS determination of ozonides, combining 
the quantitative methylation with the analysis of the thermal 
decomposition products of the ozonides. The procedure used for 
this determination was not previously reported. The ozonides were 
separated from the reaction mixture by means of the high 
performance liquid chromatography (HPLC), using an isocratic 
system. On the other hand, when ethanol is used as additive, the 
ethoxy-hydroperoxides were identified as major products. Ozonides, 
in smaller proportion, are observed too. For the analysis of these 
compounds by GC/MS, the same procedure for the determination of 
ozonides, was used. The gas chromatography profile obtained is 
discussed in detail and it is corroborated by the H1-NMR analysis. 
The analysis of the reaction products, when water was used as 
additive, revealed only the presence of aldehydes (hexanal, 
nonanal and 9-oxo-methyl nonanoate) for both techniques. The 
obtained products, in all cases, can be explained taking into 
account the Crieggee mechanism.


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