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

Abstract

The reaction of isopropanol vapor with Hg 6 ( 3 P~) atoms in the presence of nitric oxide has been investigated in a static system a t room temperature as a function of exposure time. In addition to the major products hydrogen, pinacol, and acetone found in the pure substrate reaction, the new products isopropyl nitrite, nitrous oxide, and nitrogen were observed. The effect on the reaction of the inert gas carbon tetrafluoride was also studied.Evidence is adduced for the production of excited isopropoxy radicals in the primary process, and the rise in the nitrite and acetone yields, observed upon increasing the added inert gas pressure, is ascribed to quenching of these excited species.The nitrite produced in the decomposition of MesCDOH was found to be ca. 98% MezCDONO, dictating its formation from the isopropoxy radical and not from Me2COH.A nitrite-producing dark reaction was observed when high pressures of CFd were added and the reaction could be prevented only by measures designed to exclude trace quantities of NO2 from the reaction vessel.

THE REACTION OF t-BUTYL ALCOHOL VAPOR WITH Hg 6(3P1) ATOMS

“…The reaction of H-atoms with nitric oxide has been discussed previously (6). There is probably, however, an additional step giving rise t o N20, since the yield of H-atoms calculated from the stoichiometry of reactions [28] t o [30] is inordinately high, and the water yield, though not determined quantitatively, was clearly smaller than that of NzO.…”

“…Recent investigations of the vapor-phase reactions between Hg 6(3P1) atoms and ' methanol (1, 2, 3), ethanol (4), and isopropanol (5,6) have shown that scission of the 0-H bond in each case is the dominant primary step in the reaction. What is more, the rate of abstraction of H-atoms from the substrate, by both primary fragments, rises with decreasing strength of the a(C-H) bond, the site of abstractive attack.…”

“…The essential details of apparatus, procedures, and purification techniques have been given in earlier papers in this series (2,3,6).…”

“…Light intensities were determined with propane as actinometer (14), using the differential method of Back (15) In experiments where both NO and CF4 were added, special precautions were necessary to avoid the complicating effects of the dark reaction previously found in the isopropanol system under the same conditions (6). Blank runs showed that unless NO and CF4 are stored together for a t least 12 hours and subsequently distilled into the reaction cell containing the alcohol, a t a temperature a t which NO2 has negligible vapor pressure, i.e.…”