Boron monohydride reaction kinetics studied with a high-temperature reactor

Abstract

The rate coefficients of BH radical reactions with O{sub 2}, CH{sub 4}, C{sub 3}H{sub 8}, C{sub 2}H{sub 4}, NO, and H{sub 2}O were determined over the temperature range 298-750 K in a high-temperature reactor. The BH radicals were generated by the photolysis of BH{sub 3}CO at 193 nm and monitored by laser-induced fluorescence. The absolute bimolecular rate coefficients were obtained from measurement of the BH chemical lifetime as a function of reactant number density. For the reaction of BH with O{sub 2}, a fit of the data to the standard Arrhenius expression k(T) = A exp(-E{sub a}/RT) yielded a preexponential factor of (4.9 {plus minus} 0.6) {times} 10{sup {minus}11} cm{sup 3}/s and an activation energy of 2.4 {plus minus}0.1 kcal/mol over the range 298-750 K. A rate coefficient of (1.9 {plus minus} 0.2) {times} 10{sup {minus}14} cm{sup 3}/s was found for the reaction of BH with CH{sub 4} at 675 K.