Photochemistry of the SO2, 2-pentene system at 3660 Å

✍ Scribed by Fred B. Wampler

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 458 KB
• Volume: 8
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550080611

✦ Synopsis

The photolysis of SO, in the presence of cis-and trans-2-pentene has been investigated at 3660

Quantum yield measurements of the SO, photosensitized conversion of one isomer into the other are consistent with a mechanism in which the only participating excited electronic state of SO, is the H02(3B1) state. Quantum yield measurements were made for a variation in P ~O J P ~~~, ~, ~ reactant ra.tios of 4.01-283 and 57.5-351 for the cis and trans isomers, respectively. The data are consistent with a mechanism in which a (SOz-olefin)3 collision intermediate is the precursor to the photosensitized isomeric products. The int.ermediate undergoes unimolecular decay to yield the cis and trans isomers with probabilities of 0.26 f 0.05 and 0.69 + 0.04, respectively. Estimates of the quenching rate constants at 22°C for removal of S02(3B1) molecules by cis-and trans-2-pentene are (0.633 & 0.125) X loL1 I./mole.sec and (1.00 + 0.27) X 1011 I./mole.sec, respectively. An experimentally determined photostationary composition, [trans-2-pentene]/[cis-2-pentene] = 2.3 + 0.1 was in fair agreement with that of 1.7 =t 0.7 as predicted from kinetic data derived in this study. and 22°C.