Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1251848 | Chemistry and Physics of Lipids | 2013 | 9 Pages |
•We have ozonized ethyl oleate in a tubular bubble reactor.•The main ozonation product is the ozonide of ethyl oleate.•The thermal decomposition of the ozonide of ethyl oleate was studied using DSC.•We have calculated the theoretical enthalpy of ethyl oleate ozonide decomposition.
Neat ethyl oleate was ozonized in a bubble reactor and the progress of the ozonolysis was followed by infrared (FT-IR) spectroscopy and by the differential scanning calorimetry (DSC). The ozonolysis was conducted till a molar ratio O3/CC ≈ 1 when the exothermal reaction spontaneously went to completion. A specific thermochemical calculation on ethyl oleate ozonation has been made to determine the theoretical heat of the ozonization reaction using the group increment approach. A linear relationship was found both in the integrated absorptivity of the ozonide infrared band at 1110 cm−1 and the ozonolysis time as well as the thermal decomposition enthalpy of the ozonides and peroxides formed as a result of the ozonation. The DSC decomposition temperature of ozonated ethyl oleate occurs with an exothermal peak at about 150–155 °C with a decomposition enthalpy of 243.0 kJ/mol at molar ratio O3/CC ≈ 1. It is shown that the decomposition enthalpy of ozonized ethyl oleate is a constant value (≈243 kJ/mol) at any stage of the O3/CC once an adequate normalization of the decomposition enthalpy for the amount of the adsorbed ozone is taken into consideration. The decomposition enthalpy of ozonized ethyl oleate was also calculated using a simplified thermochemical model, obtaining a result in reasonable agreement with the experimental value.