Shock wave and modelling study of the dissociation kinetics of C2F5I. Issue 7 (17th February 2021)

• Record Type: Journal Article
• Authors: Cobos, C. J.; Sölter, L.; Tellbach, E.; Troe, J.
• Is Part Of: Physical chemistry chemical physics. Volume 23:Issue 7(2021)
• Page Start: 4394
• Page End: 4403
• Publication Date: 2021-02-17
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d0cp06414a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The thermal dissociation of C2 F5 I was studied in shock waves monitoring UV absorption signals from the reactant C2 F5 I and later formed reaction products such as CF, CF2, and C2 F4 . Abstract : The thermal dissociation of C2 F5 I was studied in shock waves monitoring UV absorption signals from the reactant C2 F5 I and later formed reaction products such as CF, CF2, and C2 F4 . Temperatures of 950–1500 K, bath gas concentrations of [Ar] = 3 × 10 −5 –2 × 10 −4 mol cm −3, and reactant concentrations of 100–500 ppm C2 F5 I in Ar were employed. Absorption-time profiles were recorded at selected wavelengths in the range 200–280 nm. It was found that the dissociation of C2 F5 I → C2 F5 + I was followed by the dissociation C2 F5 → CF2 + CF3, before the dimerization reactions 2CF2 → C2 F4 and 2CF3 → C2 F6 and a reaction CF2 + CF3 → CF + CF4 set in. The combination of iodine atoms with C2 F5 and CF3 had also to be considered. The rate constant of the primary dissociation of C2 F5 I was analyzed in the framework of statistical unimolecular rate theory accompanied by a quantum-chemical characterization of molecular parameters. Rates of secondary reactions were modelled as well. Experimental rate constants for the dissociations of C2 F5 I and C2 F5 agreed well with the modelling results. The comparably slow dimerization 2CF2 → C2 F4 could be followed both by monitoring reactant CF2 and product C2 F4 absorption signals, while CF3 dimerization was too fast to be detected. A competition between the dimerization reactions of CF2 and CF3, the recombination of CF2 and CF3 forming C2 F5, and CF-forming processes like CF2 + CF3 → CF + CF4 finally was discussed.