The elimination of hydrogen fluoride from vibrationally excited 1,1,2-trifluorethane

Abstract

Sir: We have extended our recent studies1 on the elimination of HF from vibrationally excited fluoroethanes to the "hot" molecule CF2HCFH2*, formed via the cophotolysis of (CF2H)2CO and (CFH2)2CO. Low pressures of the ketones (between 60 and 600 µ total pressure, in a roughly 1:1 mixture) were used in order

Disproportionation reactions between alkyl and fluoroalkyl radicals. II. Fluoro‐ and trifluoromethyl with ethyl radicals

“…In these experiments the loss of C2H4 due to CF3 addition presents a problem, but with a unique source of both CF3 and C2H5 radicals a kinetic treatment can be used that measures reaction (5) by monitoring CF3H formation [9,12]. We did find small amounts of C2H4 in TFB photolysis, but the right-hand side of eq.…”

“…At room temperature we can assume (11) (12) TFB + hu + CF:< + COC2H5 COC2H5 -CO + C2H5 by analogy with CF3COCH3 [24,25], and this dissociative sequence should be considered to evaluate the possible participation of the CzH5CO radical in disproportionation reactions. The alternative primary decomposition mode (13)…”

“…In the current work we redetermine A(CF3, CFZH). The value of A for reaction (C) with R = CH3 has not been established [12], and its measurement, together with an investigation of reactions (C) and (D) with propyl and butyl radicals, will be presented in a subsequent paper.…”

Disproportionation reactions between CF2H and C2H5 radicals in the gas phase

“…A for R = CF2H is given above; other known values are A = 0.08-0.09 for R = CF:< [24], and A = 0.06 when R = CFH2 [23]. The occurrence of reaction (B) when R = CH3 was not established [30]. In this work we present data on reaction (B) for R = CzHs.…”

“…The other two or three products (their appearance varied from run to run) were detected only in trace amounts; one of them was identified as C2F4 by comparative retention time. Similarly, the 1,l-difluoroethylenes, CF2CH2 and CF2CD2, have been reported in the cophotolyses of TFA and acetone and TFA + acetone-ds, respectively, but the mechanism for their occurrence has not been settled [30,39,48]. Because of the uncertainty in its mode of formation the CF2CH2 is not included in the mass balance ratios, and any change would not be significant in any case.…”