Trace Species in Combustion Gases: The Formation of Sodium Metaborate
THIOKOL CHEMICAL CORP DENVILLE NJ DENVILLE United States
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The equilibrium constant for the reaction NaClg HBO2g NaBO2g HClg is determined to be, Kp 2.50 1980 deg K. Sodium vapor and boron trichloride BCl3 are reacted in a hydrocarbon-air flame contained in a tunnel burner. Conditions are such that the concentrations of HBO2 and HCl are equal to the total flows of boron and chlorine. The concentration of unreacted sodium is found by line absorption, using an experimentally determined absorption coefficient. The relative contribution of NaCl and NaBO2 to the chemically combined sodium concentration can be assessed by removing the direction proportionality between chlorine and boron flows. This is done by adding chlorine, beyond that present in the BCl3. The H-atom concentration is also required, and is inferred from the intensity of the 2pi to 2sigma0,0 OH-band.