Ion–molecule reactions in vinyl fluoride

Abstract

The ion-molecule reactions in vinyl fluoride have been studied as a function of pressure and electron energy. The C2H,-and C2HF+ fragment ions react predominantly by charge transfer while C2HBL produces C2H,F+ and C4H5'. The C2H2F7 fragment forms C2H4F+, CHFZ-, CzH3Fz+, C4H4F+, and probably C2H3 +. The rate constants for the individual reactions have been measured. The C2H3F+ ion reacts to form C3H5 +, C3H4F+, C3H3F, +, and C4H5F7 (in minor yield), both by a second order and by a third order reaction. The rate constants and product distributions from the individual reactions have been evaluated. A number of consecutive reactions have been identified and shown to be third order processes.

Ion molecule reactions in vinyl fluoride by photoionization. Effects of vibrational excitation on major reaction pathways

“…As a result the kinetics depart from pseudo-first order, and the product distribution changes with the extent of reaction. These effects are clearly seen in the data of Herman and Harrison, 2 McAskill and Harrison, 3 and Sieck et al 6 The similarity in rate constants for relaxed ions determined by those workers with those of the present study is gratifying, as is the agreement in the deactivation rates calculated for our study and those calculated 5 for the data of McAskill and Harrison. 3 It is not completely clear why the earlier ICR studies 4 • 4 do report a change in product ratios with electron energy, indicating a changing vibrational population.…”

“…The qualitative features of the data are consistent with earlier studies. 2 -6 The parent ion undergoes Reactions (1)- (3) As in previous studies, the products of Reactions (1) and (2) were found to react further by Processes (4) and (5). In…”

“…13 According to the analysis of both groups, the major vibration excited on ionization is the C=C stretch, denoted as v 1 • The other two vibrational modes shown in Fig. 1(b) are assigned to a C-F stretch v 2 and an in-plane C-F bend v 3 • Reinke et al 12 give frequencies of 1570, 1300, and 500 cm-t, respectively, for v 1 , v 2 , and v 3 • The small steps due to combinations involving v 3 can be seen in the photoionization data. However, the spacing of lines in the exciting spectrum is not sufficiently dense to allow the states involving v 1 and v 2 to be distinguished.…”

“…to be -9 kcal/mole; the thermochemistry of Reactions (2) and (3) is not as well characterized, but they have been estimated to be exothermic by 12 and 16 kcal/ mole, respectively. 1 In recent years several groups have studied Reactions (1)- (3) using electron impact ionization, with differing conclusions concerning the kinetics and mechanism of these reactions.…”

Termolecular ion–molecule reactions involving C3H5+

“…The C3H,+ produced by reaction of the molecular ion reacts further by reaction 4 to [4] C3Hsf + 2 C2H3F -> C5H7+ + (HF + C2H3F) produce C5H,+ in a reaction which has been shown (4) to be second order in C2H3F. Again no accurate value for the rate coefficient was obtained although it was estimated that it must 'The C , H q f has also been shown (2.…”