Shock wave and modelling study of the dissociation pathways of (C2F5)3N. Issue 19 (26th April 2019)

• Record Type: Journal Article
• Authors: Cobos, C. J.; Hintzer, K.; Sölter, L.; Tellbach, E.; Thaler, A.; Troe, J.
• Is Part Of: Physical chemistry chemical physics. Volume 21:Issue 19(2019)
• Page Start: 9785
• Page End: 9792
• Publication Date: 2019-04-26
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c9cp01142k
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The thermal decomposition of perfluorotriethylamine, (C2 F5 )3 N, was investigated in shock waves by monitoring the formation of CF2 . Abstract : The thermal decomposition of perfluorotriethylamine, (C2 F5 )3 N, was investigated in shock waves by monitoring the formation of CF2 . Experiments were performed over the temperature range of 1120–1450 K with reactant concentrations between 100 and 1000 ppm of (C2 F5 )3 N in the bath gas Ar and with [Ar] in the range of (0.7–5.5) × 10 −5 mol cm −3 . The experiments were accompanied by quantum-chemical calculations of the energies of various dissociation paths and by rate calculations, in particular for the dissociation of C2 F5 via C2 F5 → CF3 + CF2 . The overall reaction can proceed in different ways, either by a sequence of successive C–N bond ruptures followed by fast C2 F5 decompositions, or by a sequence of alternating C–C and C–N bond ruptures. A cross-over between the two pathways can also take place. At temperatures below about 1300 K, yields of less than one CF2 per (C2 F5 )3 N decomposed were observed. On the other hand, at temperatures around 2000 K, when besides the parent molecule, CF3 also dissociates, yields of six CF2 per (C2 F5 )3 N decomposed were measured. The rate-delaying steps of the dissociation mechanism at intermediate temperatures were suggested to be the processes (C2 F5 )NCF2 → (C2 F5 )N + CF2 and (CF2 )N → N + CF2 . The reduction of the CF2 yields at low temperatures was tentatively attributed to a branching of the mechanism at the level of (C2 F5 )2 NCF2, from where the cyclic final product perfluoro- N -methylpyrrolidine, (C4 F8 )NCF3, is formed which was identified in earlier work from the literature.