Photolysis of alkyl iodides at 147.0 nm. The reaction H + CnH2n + 1I → HI + CnH2n + 1

✍ Scribed by R. E. Rebbert; S. G. Lias; P. Ausloos

• Publisher: John Wiley and Sons
• Year: 1973
• Tongue: English
• Weight: 697 KB
• Volume: 5
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550050515

✦ Synopsis

The 147 nm (8.4 eV) photolysis of gaseous C2H51, n-C3H71, and sec-C3H71 was investigated in the presence of and absence of HI. The main overall processes are:

These dissociative processes occur mainly as a result of initial cleavage of the weak C-1 bond, followed by decomposition of the internally excited alkyl radicals. In all cases, approximately 5-10yo of the alkyl radicals thus formed do not undergo dissociation at pressures around 3-7 torr. There is also evidence for the elimination of HI as well as C-C cleavage in the primary dissociation. The former is indicated by deuterium labeling expcriments and the formation of cyclopropane (Ip = 0.04) as a product in the photolysis of n-C3H7I.

a constant source of H a t m whose quantum yield can be exactly determined, it was feasible to obtain accurate values for k,/kb: Because the processes listed above provide a H + CnHPn+II + C&2m+, + HI b H + H I + H z + I For thermallyequilibrated H atoms (300 K), k,/kb is 0.44 f 0.04, 0.57 f 0.06,0.95 i 0.1, and 0.024 f 0.01 for CZHJ, n-C3H7I, sec-CtH71, and CZHSBr, respectively. * Work supported in part by the US. Atomic Energy Commission.