Reactions of Thiyl Radicals. X. Photolysis of Ethyl Sulfide Vapor

Abstract

The photolysis of ethyl sulfide vapor at 2537 r\ has been investigated as a function of substrate and CF4 pressure, time, and temperature. Reaction products with quantum yields in parentheses are ethyl disulfide (0.178), ethane (0.138). butane (0.086), ethanethiol (0.096), 4-methyl-3-thiahexane (0.034) and 4-methyl-3.5-dithiaheptane.Ethyl and ethylthiyl radicals are formed in the primary process and the product yields indicate a net primary decomposition quantum yield of 0.48. A reaction mechanism involving subsequent reactions of the primary fragments is proposed and explains the observed products and the observed variation in rates. Excited radicals and hot radical combination products play a minor role in this system, in contrast to the behavior of lower molecular weight sulfides. Secondary photolysis of the disulfide produced and consumption of ethanethiol are important factors in determining the time dependence of reaction rates in this system. La photolyse de la vapeur de sulfure d'ethyle a 2537 r\ a ete etudiee en fonction de la nature du substrat et de la pression de CF4 ainsi que du temps et de la temperature. Les produits de la reaction, dont les rendements quantiques sont donnes entre parentheses. sont les suivants, disulfure d'ethyle (0.178) ethane (0.138). butane (0.086) ethanethiol (0.096), methyl-4 thia-3 hexane (0.034), et methyl-4 dithia-3,5 heptane.Les radicaux ethyle et ethylthiyle sont formes dans la premiere phase et les rendements de produits indiquent fort nettement un rendement quantique de la decomposition primaire egal a 0.48. Un mecanisme reactionnel impliquant des reactions subsequentes des fragments primaires est propose: celui-ci permet d'ailleurs d'expliquer la formation des produits observes ainsi que les fluctuations observees dans les vitesses deformation. Les radicaux excites et les produits de combinaison de radicaux chauds jouent, en realite. un r61e negligeable dans ce systeme. ce qui va a I'encontre du compoi-tement des sulfures ayant des poids moleculaires plus bas. La photolyse secondaire du compose disulfure obtenue ainsi que la consommation d'ethanethiol sont des facteurs importants pour determiner dans ce systtme la dependance existagt entre le temps et les vitesses de la reaction.[Traduit par le journal]

Reactions of thiyl radicals. XII. Triplet mercury photosensitized decomposition of ethyl sulfide in the gas phase

“…Methyl sulfide has been studied in both direct (1) and Hg-sensitized decomposition (2), but only the direct photolysis of ethyl sulfide has been investigated (3).…”

“…The apparatus and procedures ill general have been particularly as affect product yields described previously (2,3). In the sensitized experiments fro111 which h.,~isl,ropor~iona~iOII/h.ConI~~I1a~ioI, values the light source was a Hanovia 68SA45 low pressure for thiyl radicals can be con~puted.…”