FTIR Analysis of Triethylamine Borane and White Fuming Nitric Acid Gaseous Combustion Products

摘要

Rocket exhaust products from the combustion of conventional liquid propellant combinations such as hydrazine and its derivatives with nitrogen tetroxide have been studied extensively. However, little work has been done on the characterization of exhaust products resulting from the ignition of less-toxic green liquid hypergolic propellants. In this work, we experimentally investigate the gaseous combustion products of a green hypergolic combination of triethylamine borane (TEAB) and white fuming nitric acid (WFNA). We use a drop test experiment to generate these gases, and thereafter route them into a gas cell for the collection of a spectrum using a FTIR spectrometer. To perform the analysis, we divide the spectrum obtained into the fingerprint (1000 cm~(-1) to 1500 cm~(-1)) and the functional group (1500 cm~(-1) to 4000 cm~(-1)) regions, and resolve the peaks into various functional group vibration modes as well as propose the presence of various species in the gas sample. Using spectral libraries and spectral data available in the literature, we identify the chemical signatures of O-H and C-H stretching vibrations, N-H bond vibrations, as well as absorbance peaks corresponding to water vapor (H_2O), methane (CH_4), carbon monoxide (CO), carbon dioxide (CO_2), and the vapors of triethylamine borane (C_6H_(18)BN) and nitric acid (HNO_3). In addition, we observe the condensation of the gaseous products from the decrease in absorbance of the different spectral peaks as a function of time.