The SO2(3B1) photosensitized isomerization of cis- and trans-1,2-difluoroethylene

✍ Scribed by Fred B. Wampler

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 319 KB
• Volume: 8
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550080405

✦ Synopsis

Quantum yield measurements for the S02(3B1) photosensitized isomerization of cis-1,2-diflu%roethylene have been made at 3712 A and 22°C. The

[ S O ~] / [ C ~T -C ~F ~H Z ]

ratio was varied from 47.4 to 455 and the quantum yield measurements over this variation of concentration ratios were consistent with a mechanism in which S02(3B1) molecules and the cis isomer form a collision intermediate which decomposes with a probability of 0.42 i 0.17 and 0.58 & 0.17 of producing transand cix-I ,2-difluoroethylene, respectively. When SO2 was subjected to prolonged irradiations in the presence of initially either pure cir-or pure frans-l,2-difluoroethylene, a photostationary composition, [cis]/[trans] = 1 .O f 0.2, was obtained. The rate constant at 22°C for removal of S02(3B1) molecules by cis-1,2difluoroethylene was estimated to be (1.72 f 0.72) X 1O' O l./mole.sec.