J. Niedzielski, W. Makulski, J. Gawlowski
1978
Citations
0
Influential Citations
14
Citations
Journal
Journal of Photochemistry
Abstract
Abstract The photolysis of gaseous 1-pentene was carried out in a static system using the xenon resonance line at 147 nm (8.4 eV) at pressures in the range 0.5 – 400 Torr (0.7 – 533 hPa). Only decomposition processes were studied and no attempt was made to establish the pattern of free radical reactions. The major dissociation products observed were ethylene, allene, propylene, 1,3-butadiene, acetylene and propyne. The minor products included methane, ethane, propane, some C 5 H 8 and C 4 H 6 hydrocarbons, and 1-butene. The radical species were identified using scavengers such as oxygen, H 2 S and HI. The pressure dependence of the yields of the major radicals (C 3 H 5 , CH 3 , C 2 H 5 , C 2 H 3 and C 3 H 7 ) was established. The C 2 H, C 4 H 5 , C 4 H 7 , CH 2 and C 3 H 3 radicals were found to be unimportant. The primary decomposition channels are established. The main processes are the cleavage of a CH bond with a yield φ of 0.45 – 0.48 and the cleavage of a CC bond with a yield φ of 0.47. The allylic CC bond appears to be the only CC bond which undergoes primary rupture. All four primary intermediates, i.e. C 5 H 9 , C 3 H 5 , C 2 H 5 and H, are energized. The radicals either decompose (isomerization prior to decomposition is possible in some cases) or undergo collisional stabilization; some hydrogen atoms add to the double bond prior to thermalization. Some details of the secondary processes are established but the overall mechanism is too complex to be fully interpreted.