Photolysis of Diisopropyl Peroxide¹

THE REACTION OF ISOPROPANOL VAPOR WITH Hg 6(3P1) ATOMS: PART II: REACTION IN THE PRESENCE OF NITRIC OXIDE

“…Thus a t t = 15 minutes we find @(Hz) = 0.18; whereas for the uninhibited reaction under the same conditions the value is 0.56 (1). Owing to the third-body restriction on [6], the primary H-atoms are probably not efficiently scavenged by NO, and abstraction from the substrate through [3] would still be operative.…”

“…Our finding that MezCDONO forms in the MeCDOH + S O system confirms this reaction. Extensive evidence is available for the occurrence of [6] and [7] to explain NzO and Hz0 formation from H atoms and NO (10)(11)(12)(13)(14)(15)(16)(17)(18) For personal use only. addition, in the Hf YO system, it has been recently demonstrated that X z is a significant product (19).…”

“…Since [6] is inefficient, there will be a finite concentration of H atoms in the system, and therefore back reaction through [lo] can occur. In this step, A will likely be R l e z c~H , since isopropoxy radicals can react with the substrate via 131, and be fixed as the nitrite in [j], Furthermore, our observation that pinacol, which clearly forms via [13], is an important product even a t the high NO concentrations used in this study indicates that the l U e 2 t O~ radicals show low reactivity to NO, thereby suggesting high steady-state levels for these species.…”

“…10 kcal/mole, thereby leading to a strong third-body restriction on the nitrite-forming step in these systems. Pertinently McMillan (6)(7)(8) has recently reported the formation of excited alkoxy radicals in the photolysis of dialkyl peroxides, attributable to the energy difference between D(R0-OR) and that of the exciting quanta. T o investigate the importance of excited isopropoxy radicals in the present system, the effect of increasing pressure of inert gas on the nitrite yield has been examined.…”

Primary Processes in the Photochemical Decomposition of Nitroalkanes

“…It is impossible to tell from our results if there is another primary process yielding acetaldehyde directly by an intramolecular decomposition as reaction I1 which was originally postulated by Hirschlaff and Norrish(l), or if other reactions such as l l b can account for it. McMillan (15) has shown that for the isopropoxy radical the following reactions occur :…”