Kinetics of Hydrogen Halides in Shock Waves: HCl and DCl

Decomposition rates of HCl and DCl, diluted in an Ar bath, were studied behind incident shock waves over the temperature range 2800° to 4600°K, by application of infrared emission techniques. Within a factor of 2, the dissociation rate constants (cubic centimeters·moles·second units) were found to be as follows. HCl: k1=1021.83T−2 exp (−102 170/RT); DCl: k1=1021.90T−2 exp (−103 200/RT). Evidence is presented to show that a superior match is achieved between experimental and computed time derivatives for HCl and DCl when an activation energy of about 70 kcal is taken for the dissociation step; in this case, a k1=1012.82× exp (−70 000/RT) is found for HCl and DCl.