Laser-Induced Reactions of Hexafluorobenzene and Selected Hydride Compounds

Article abstract of DOI:10.1021/j100286a014

Infrared-laser-induced reactions between C6F6 and general hydrides R-H (R = H, D, CH3, HC<*>C, H2C=CH, and Cl) were studied by irradiating C6F6 at 1027 cm^-1 in C6F6/R-H mixtures.In general, two competitive pathways involving C-F bond cleavage in C6F6 were observed as follows: (1) C6F6 + R-H <*> C6F5H + R-F and (2) C6F6 + R-H <*> C6F5R + HF.C6F6 decomposition also took place to a minor extent depending on the mole fraction of C6F6 and gave rise to C2F4 and C2H2.From infrared and GC/MS analysis of the product mixtures after 20-200 pulses, C6F5H was observed in all reactions except that involving D2.When D2 was used C6F5D was the major product.C6F5H was the major product in the reactions involving H2 and C2H2.In the reaction with C2H4, C6F5H was the major product derived from C6F6 though C2H2 was the major product of the reaction.The large amount of C2H2 seems to be derived from an additional sensitized decomposition of C2H4.C6F5H was present in minor amounts in the reaction with CH4 and HCl.Besides C6F5H, other monosubstituted products derived from C6F6 were also formed, generally within 20-100 pulses.Thus, C6F5CH3, C6F5CH=CH2, C6F5C<*>CH, and C6F5Cl were produced, respectively, in the reaction of C6F6 with CH4, C2H4, C2H2, and HCl.In the first and last cases these products were the major ones observed.The results are discussed mechanistically in terms of the initial formation of the C6F5^. radical and synthetically in terms of the utility of obtaining selective-laser-induced reduction of C6F6.