Oxidation of (CD3)2C.X Radicals. I. Reaction of Propane and Isopropyl Radicals with Atomic Oxygen

Article abstract of DOI:10.1246/bcsj.60.3739

The raection of oxygen atoms with propane-1,1,1,3,3,3-d6, (CD3)CH2, in a fast-flow system was studied with a photoionization mass spectrometer.Isopropyl-d6 radicals, (CD3)2CH, formed by the initial hydrogen abstraction at the 2-position were detected directly. The subsequent reaction of (CD3)2C^.H radicals with atomic oxygen proceeds by both an deuterium abstraction (61percent) and an oxygen addition reaction (39percent).The product in the deuterium abstraction was CD2CHCD3 and those in the oxygen addition were (CD3)2CO (18percent) and CD3CHO (21percent). Competitition experiments show that (CD3)2C^.H radicals react (0.029 +/- 0.004) times as fas with O2 as with O(3P).In the presence of an excess of O2, CD2CHCD3 was observed in decreased yield (20percent) and (CD3)2CO and CD3CHO increased to 32 and 44percent, respectively.The rate data for Reaction 3 were fitted by an Arrhenius expression: k₃=(2.0^+1.0_-0.7)*10^-10 exp<-(6086 +/- 392 cal mol^-1)/RT> cm³ molecule^-1 s^-1 (381-627 K).The rate constant of Reaction 3 obtained from the yields of products was 7.9*10^-15 cm³ molecule^-1 s^-1 at 298 K.