Ethyl peroxy

The rapid decrease of the quantum yield of C2 hydrocarbons with increase of oxygen pressure is indicative of the fast reaction of ethyl radicals with oxygen to form the ethyl peroxy radical... 

Blei (1-Methyl-l-phenyl-ethyl-peroxi)-trimethyl- XIII/7, 112F./E13/1, 193 (Salzbildung)... 

LFP/UV, Excimer laser photolysis, UV absorption detection of hydrocarbon. LFP/PIMS, Excimer laser photolysis, photoionization mass spectrometric monitoring of hydrocarbon. RR, Relative rate determination. DF/MS Discharge flow production of radicals, mass spectrometric monitoring of hydrocarbon radicals. PR/UV, Pulsed radiolysis in 760 Torr H2, UV absorption detection of ethyl and ethyl peroxy. 

Fig. 2.34. Orbital arrangements of the two lowest electronic states of the ethyl peroxy...

Fig. 2.35. Potential energy surface for the ethyl + O2 reaction involving the first electronically excited level of the ethyl peroxy radical.

Formation and dissociation of hydro-, methyl- and ethyl-peroxy radicals ... 

Jonsson and co-workers [90, 91] have also reported enthalpy values from semiempirical and a number of higher level ab initio calculations. Sheng et al. [10, 92] report data on the ethyl peroxy and 2-hydroperoxide ethyl radicals and on the stable ethylhydroperoxide. Schaefer and co-workers [93, 94] have reported results on the ethyl peroxy and 2-hydroperoxide ethyl radicals. Sumathi and Green [95] have reported results from ab initio molecular orbital calculations at the Hartree-Fock level for S and Q (7) and complete basis set (CBS-Q atomization reaction) level for enthalpies on methyl, ethyl, isopropyl, and tertbutyl hydroperoxides and their corresponding methylperoxides. 

Peroxy methyl and ethyl peroxy radicals are needed as reference species as well and are calculated with the isodesmic reactions listed in Table 3.6. The accuracy of the results has already been discussed in section 3.2.1.2. 

The initially stabilized ethyl peroxy adduct is not stable at higher temperatures. Predictions of its unimolecular reactions for the same conditions are presented in Fig. 14. The major dissociation channel leads to C2H5 + O2 and the only other important reaction path produces C2H4 + HO2. Due to the higher 4-factor, the dominance of the redissociation channel increases with temperature. For the dissociation... 

Fig. 15. MultiWell results of the decay of chemically activated ethyl peroxy at 700 K and 1 atm He. The separation line divides the time range into the prompt (left) and the...

Hasson AS, Tyndall GS, Orlando JJ (2004) A product yield study of the reaction of HO2 radicals with ethyl peroxy (C2H5O2), acetyl peroxy (CH3C(0)02), and acetonyl peroxy (CH3C(0)CH202) radicals. J Phys Chem A 108 5979-5989... 

The yields of nitric ester (alkyl nitrate) in the above scheme is known to become larger as the number of carbon atoms in the alkyl radical increases. For example, the reaction of ethyl peroxy radical, C2H5O2 and NO,... 

An interesting instmmental development has been described by Hanson et al. [184], who demonstrated the ability of PTR-MS to detect peroxy radicals. These radicals were produced in a laminar flow reactor via an initial reaction of atomic chlorine with an alkane to produce an alkyl radical, which was followed by reaction with O2 to generate the peroxy radical. The PTR-MS instrument was operated under extremely low E/Nconditions (18-34 Td), which ensured that H30+(H20) cluster ions (n > 0) dominated rather than bare H3O+ reagent ions, because alkanes do not react with protonated water clusters. The detection of methyl and ethyl peroxy radical species was found to be adversely affected by water vapour, whereas that for the cylcohexyl peroxy radical was found to be much less affected. A particularly powerful feature of this work was the ability to map the formation of product distributions in organic reaction systems involving peroxy radicals. 

The atmospheric lifetime of tert-butyl hydroperoxide with respect to reaction with OH radicals is of the order of few days. Similar to other hydroperoxides, photolysis could also have an important contribution to the atmospheric removal of tert-butyl hydroperoxide. The reaction of OH with tert-butyl hydroperoxide is expected to proceed through H-atom abstraction from the —OOH group to give (CH3)3C02 radicals which will react with NO, other peroxy radicals, and ozone as suggested in the previous sections for methyl and ethyl peroxy radicals. 

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