Ethyl Oleate and Ethyl Elaidate Ozonides: Thermal Decomposition and Photolysis

Abstract

Highly pure ethyl oleate and ethyl elaidate were ozonized to their secondary ozonides (respectively EO-SOZ and EE-SOZ). The decomposition enthalpies of EO-SOZ and EE-SOZ were determined by DSC (Differential Scanning Calorimetry) and found, respectively, at -266 kJ/mol and -264 kJ/mol, a value much closer to the theoretically calculated upper limit of -278 kJ/mol than the decomposition enthalpy of -243 kJ/mol measured on EO-SOZ prepared from an ethyl oleate sample conforming to the European Pharmacopoeia. Although a considerable amount of heat was liberated, EO-SOZ and EE-SOZ cannot be defined as explosive based on their DSC traces at a heating rate of 10 • C/min. Pure EO-SOZ and EE-SOZ show a decomposition peak at the DSCs of 137 • C and 139 • C, respectively. The thermal decomposition of EO-SOZ and EE-SOZ was studied also by FT-IR spectroscopy showing that the decomposition involves the loss of the ozonide infrared band at 1110 cm −1 and the formation of the expected decomposition products (pelargonic acid, pelargonaldehyde, ethyl azelate, etc.). The kinetics of the photochemical decomposition of EO-SOZ and EE-SOZ were studied by FT-IR spectroscopy, and the relative rate constants were determined. EO-SOZ when overozonized forms a spin adduct with nitrosobenzene and the relative nitroxyl radical was clearly detected by the Electron Spin Resonance (ESR). Secondary ozonation products known as trioxides may be responsible for these adducts.

Influence of Storage Temperature on the Composition and the Antibacterial Activity of Ozonized Sunflower Oil

“…These data suggest that the ozonides and hydroperoxides disappear while carboxylic acids are formed which is in accordance with previous works (Cataldo 2014(Cataldo , 2015a. It is well known that carboxylic acids are by-products of the ozonolysis reaction (Omonov, Kharraz, and Curtis 2011).…”

Thermal Decomposition of Ozonized C70Fullerene and Its Reducing Properties Toward Silver Ions

“…The amount of heat released is consistent with the presence of secondary ozonide and/or peroxidic moieties since the measured value is in agreement with thermodynamic calculations (15) and calorimetric measurements made on different secondary ozonides of unsaturated fatty acid esters (16,17) and 1-alkenes (18,19). The…”

“…This implies that the secondary ozonides are completely removed by the thermal treatment with the formation of other oxygenated moieties but also with release of volatile products as already observed on the thermal decomposition of other ozonides (16,17,19) as well as in the thermal decomposition of C 60 ozopolymer.…”

“…The presence of aldehyde groups is suggested by the broad band at 2600 cm -1 , and by the bands at about 1393 and 1372 cm -1 attributable to the aldehyde C-H rocking (22). The secondary ozonide bands are definitely located at 1170 and moreover at 1072 cm -1 (15)(16)(17) and appear slightly shifted with respect to the ozonide bands of C 60 ozopolymer observed at 1188 and 1102 cm -1 (14). However, the thermal treatment of C 70 ozopolymer at 350°C under nitrogen leads to the same results already reported for C 60 ozopolymer under the same treatment (see (ii) As a consequence of the thermal treatment, the band at 3400 cm -1 due to OH stretching undergoes a drastic reduction of its original intensity.…”

On the Action of Ozone on Phospholipids, a Model Compound of the External Envelope of Pericapsidic Viruses like Coronavirus. Part 1

“…The difference spectrum shows also the growth of a band at 1102 cm −1 accompanied by a weaker band at 1055 cm −1 , which appear at 1093 and 1062 cm −1 respectively in the PPL-O spectrum. These bands were already observed in the ozonation of fatty acids esters, glycerides and unsaturated hydrocarbons and fall in the spectral range assigned to secondary ozonides (Cataldo 2013(Cataldo , 2015a(Cataldo , 2015b; De Almeida-Kogawa et al 2015; Fisher and Dussault 2017). Other new spectral features evidenced in PPL-O with the difference spectra are the band at about 1200 cm −1 which can be assigned to cyclic C-O-C symmetric stretching of the 1,3,4-trioxolane ring, accompanied also by the asymmetric stretching at about 950 cm −1 (Cataldo 2013), as in the case of epoxide rings (Nakanishi 1972).…”