Addition of trichloromethyl radicals to tetrachloroethylene

Abstract

Abstract'The gamma-radiation-induced free-radical chain reactions in liquid CC14-C&L-c-CsHly mixtures were studied in the temperature range of 363-448°K. T h e main products in this system are chloroform, hexachloropropene and chlorocyclohexane. These products are formed via reactions (1)- (5): (1) From this result and the previously determined Arrhenius parameters of reaction ( l ) , ti? is I'iiund t o he given by log k ? (l/mol-sec) = 7.58 -9.?9//1

Wavelength dependence of the quantum efficiencies of the primary processes in formaldehyde photolysis at 25°C

“…In a recent study of the 3130-A photolysis of CH20 at 25"C, we have found that $1 and $2 can be determined relatively simply using isobutene as an H-atom scavenger [19]. We have applied this technique in the present study to provide seemingly reliable new estimates of $1 and $2 at selected wavelengths from 2890 to 3380 A.…”

“…The experimental setup and the method of gas chromatographic analysis were the same as that used in the previous work [19]. In order to isolate the different wavelengths from the high-pressure mercury arc (Osram HBO 500 W), we used a high-intensity grating monochromator (Schoeffel GM 250).…”

Kinetics of fluorescence decay of SO2 excited in the 2662–3273 Å region

“…Another interesting feature of these data is the regular enhancement of the quenching rate constant for the L state with excitation at the longer wavelengths; k4(2662)/k4(3130) is approximately constant, independent of the nature of the quenching gas. This effect has been inferred from less direct measurements of k4/k& by Mettee [33] and Horowitz and Calvert [34] from steady-state fluorescence studies. The effectiveness of the L state quenchers appears to be related to the polarizability of the molecules as suggested in other studies of excited SO2 singlet and triplet quenching [33-381. Presumably the excited SO2 molecule acts as an electrophilic reactant on collision with a polarizable molecule to form a highly polarized charge-transfer complex which may enhance intersystem crossing or internal conversion of the excited SO2 species.…”

“…From the kinetic mechanisms I1 and I11 presented, we would expect eqs. (33) and (34) to describe the ratio of the intensities for the steady-state condition (Zs/I&: (33) Using eqs. (33) and (34) and the appropriate kinetic data which we obtained from the fitting of the Zso/ILo-pressure data and the Stern-Volmer quenching constants we simulated the conditions employed by Shaw and coworkers.…”

“…(33) and (34) to describe the ratio of the intensities for the steady-state condition (Zs/I&: (33) Using eqs. (33) and (34) and the appropriate kinetic data which we obtained from the fitting of the Zso/ILo-pressure data and the Stern-Volmer quenching constants we simulated the conditions employed by Shaw and coworkers. We estimated the ratio ( Z s l l~)~~ and the fraction of the total fluorescence from the long-lived state -[ZL/(Zs + I L ) ] for the two seemingly realistic mechanism choices I1 and I11 (see Table V).…”