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...

Public reporting burden for this collection of information is estimated to average 1 fiour per response, including ttie time for reviewing instructions, searctiing 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 Sen/ices, Directorate for Infomiation 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 infomiation if it does not display a currently valid 0MB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) AFRL-PR-ED-TP-2003-007 SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)Air Force Research Laboratory (AFMC) AFRL/PRS 5 Pollux Drive Edwards AFB CA 93524-7048 SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S NUMBER(S) AFRL-PR-ED-TP-2003-007 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTES ABSTRACT U8 SUMMARYThe synthesis of three new families of heterocycHc based salts was undertaken and accomplished. Three triazole systems, 1-H-l, 2, 4-triazole 4-amino-l, 2, 4-triazole, and 1-H-l, 2, 3-triazole were used as proton bases with nitric (HNO3), perchloric (HCIO4), and dinitramidic ("HN(N02)2") acid systems. In all cases, stable salts were recovered and folly characterized by vibrational spectra (IR, Raman), multinuclear nmr spectroscopy, material balance, density measures, elemental analyses, as well as DSC, TGA and initial safety testing (impact). Many of these salts have melting points well below 100°C, yet high decomposition onsets, defining them as new, highly energetic members of the well known class of materials identified as ionic liquids. INTRODUCTIONThe Air Force continues a quest for new energetic materials as part of its basic and apphed research program. The general requirements for the molecules include, (1) High density and energy; (2) Thermal/Storage stability; (3) Low handling hazards (e.g., low sensitivity to impact, fiiction, electrostatic discharge, and low toxicity); and (4) Simple production routes (i.e., three or less synthesis steps) for low cost. In our laboratory, we have been pursuing the synthesis of new energetic salts. Energetic materials that are saU-based often possess advantages over nonionic molecules. First, salts tend to have very low vapor pressure, which essentially eliminates the risk of exposure of personnel to new materials via a major exposure route (inhalation). Second, ionic compounds often have higher density than atomically similar, nonionic molecules.

Public reporting burden for the 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 the 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 Washington Headquarters Services, Directorate for Information Operations and Reports, 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 a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. Although some of the descriptors that appear in our QSPRs were designed to describe chemical reactions, we infer that they serve in this study to quantify interactions between the cation and anion. Melting-point QSPRs were then derived from molecular orbital, thermodynamic, and electrostatic descriptors. Good correlations with the experimental data were found. The correlation coefficients for three-parameter melting-point QSPRs and for one-parameter density QSPRs exceed 0.9. Although some of the descriptors that appear in our QSPRs were designed to describe chemical reactions, we infer that they serve in this study to quantify interactions between the cation and anion.3