Molecular beam mass spectrometry measurement of 1-butene pyrolysis and combustion products: Stable and active species profiles, and, Combustion modeling of benzene, phenol, anisole and cyclopentadiene thermodynamic parameters and elementary reaction kinet

A molecular-beam-sampling mass spectrometric apparatus (MBMS) is modified for on line analysis of combustion product; reactive intermediates/radicals and stable species, in a flow tube reactor at reduced pressures and elevated temperatures. This apparatus utilizes both a vacuum ultraviolet (VUV) photoionization time-of-flight mass spectrometer (TOF) and an electron impact (EI) ionization quadrupole mass spectrometer (QMS). The molecular beam is shaped by a series of skimmers from a low pressure, fully developed laminar flow coupled soft Mach number expansion and transfers the combustion products from the reactor to the analysis apparatus. The component mole fraction is conserved in the sampling process. The 1-butene pyrolysis and combustion products versus reactor temperature are ionized, separated and analyzed by the dual mass spectrometers.; The molecular beam quadrupole mass spectrometer (QMS) with a head on axial ionizer was calibrated directly for the hydrocarbons and oxygenated hydrocarbons in the reactor Measurements of the QMS sensitivity of stable hydrocarbons lead to the relative ionization efficiency which can be successfully predicted by the standard 70 ev electron impact ionization cross sections. Mole fractions of radicals in the reactor were estimated from the standard 70 ev electron impact ionization cross section group additivity approach. The relative ionization efficiency of radicals are obtained from the precursory molecules for which direct calibration was made.