No abstract

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)Air Force Research Laboratory (AFMC) AFRL/RZS SPONSOR/MONITOR'S Pollux Drive NUMBER(S)Edwards AFB CA 93524-70448 AFRL-RZ-ED-JA-2008-090 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution unlimited (PA# 08149A) SUPPLEMENTARY NOTESPublished in J. Phys. Chem. A 2008, 112, 7816-7824. © 2008 American Chemical Society. ABSTRACTA class of room temperature ionic liquids (RTILs) that exhibit hypergolic activity towards strong nitric acid is reported. Fast ignition of dicyanamide ionic liquids when mixed with nitric acid is contrasted with the reactivity of the ionic liquid azides, which show high reactivity with nitric acid, but do not ignite. The reactivity of other potential salt fuels is assessed here. Rapid-scan, Fourier Transform infrared (FTIR) spectroscopy of the pre-ignition phase indicates the evolution of N 2 O from both the dicyanamide and azide RTILs. Evidence for the evolution of CO 2 and isocyanic acid (HNCO) with similar temporal behavior to N 2 O from reaction of the dicyanamide ionic liquids with nitric acid is presented. Evolution of HN 3 is detected from the azides. No evolution of HCN from the dicyanamide reactions was detected. From the FTIR observations, biuret reaction tests and initial ab initio calculations, a mechanism is proposed for the formation of N 2 O, CO 2 and HNCO from the dicyanamide reactions during pre-ignition. SUBJECT TERMS SECURITY CLASSIFICATION OF:17 ReceiVed: April 28, 2008; ReVised Manuscript ReceiVed: June 2, 2008 A class of room-temperature ionic liquids (RTILs) that exhibit hypergolic activity toward fuming nitric acid is reported. Fast ignition of dicyanamide ionic liquids when mixed with nitric acid is contrasted with the reactivity of the ionic liquid azides, which show high reactivity with nitric acid, but do not ignite. The reactivity of other potential salt fuels is assessed here. Rapid-scan, Fourier transform infrared (FTIR) spectroscopy of the preignition phase indicates the evolution of N 2 O from both the dicyanamide and azide...

The rate coefficients for the reaction of OH with CH3D (k 1), CH2D2 (k 2), CHD3 (k 3), CD4 (k 4), and CH4 (k 5) as well as that of OD with CH4 (k 6) have been measured using the pulsed photolytic production of OH followed by its detection via pulsed laser induced fluorescence. k 1−k 4 and k 6 were measured between ∼220 and ∼415 K, while k 5 was measured down to 195 K. The measured rate coefficients do not strictly obey the Arrhenius expression. However, below 298 K, they can be represented by the expressions (in cm3 molecule-1 s-1):  k 1 = (3.11 ± 0.44) × 10-12 exp[−(1910 ± 70)/T]; k 2 = (2.3 ± 1.2) × 10-12 exp[−(1930 ± 250)/T]; k 3 = (1.46 ± 0.22) × 10-12 exp[−(1970 ± 70)/T]; k 4 = (1.00 ± 0.22) × 10-12 exp[−(2100 ± 120)/T]; k 5 = (1.88 ± 0.11) × 10-12 exp[−(1695 ± 30)/T]; k 6 = (1.68 ± 0.12) × 10-12 exp[−(1640 ± 40)/T]. The obtained values of the rate coefficients and kinetic isotope effects are compared with values previously measured or calculated by other groups. The atmospheric implications of this data are briefly discussed.