SITE PROPENSITIES FOR HCL AND DCL FORMATION IN THE REACTION OF CL WITH SELECTIVELY-DEUTERATED PROPANES

We report on the gas-phase reaction of Cl with CH3CD2CH3 and CD3CH2CD3 to form HCI or DCI. Cl atoms are generated by the 351-nm photolysis O f C12, and both the HCI and DCI products are detected via 2 + 1 multip hoton ionization at approximately 240 nm. The use of labeled compounds allows positive identification of individual reactive sites within th e propane molecule. With respect to the reaction products over the qua ntum states probed, DCI is formed with nearly equal probability indepe ndent of whether CH3CD2CH3 or CD3CH2CD3 is the target molecule. For HC I formation, Cl reacting with CH3CD2CH3 generates approximately 1.5 ti mes more HCI than does Cl reacting with CD3CH2CD3. On a per site basis , we conclude that the middle carbon site is more reactive than an end site, and the overall results are discussed in terms of possible reac tion mechanisms.