Gas absorption with an unusual chemical reaction: the chlorination of toluene

The rate of absorption of chlorine in a laminar jet of toluene, and the corresponding bulk liquid temperature increases, have been measured as a function of contact time. Since the reaction rate is very highly dependent on the concentration of dissolved chlorine, bulk mixing of the jet on entering the receiver effectively ‘freezes’ the reaction and enables experimental determination of the ratio

This ratio is independent of the mass diffusion coefficient for 1st order kinetics, and numerical studies show this is also true for nth order reactions. The ratio therefore should be particularly valuable for abstracting kinetic information from absorption rate data in systems where interfacial turbulence may occur. A numerical analysis, which takes into account the increasing interface temperature, indicates that the overall concentration dependency of the chlorine reaction rate can be fitted by an empirical fifth order equation.