Reaction kinetics of carbonyl sulfide with aqueous ethylenediamine and diethylenetriamine

Abstract

The reaction in aqueous solution between carbonyl sulfide (COS) and the polyamines ethylenediamine and diethylenetriamine has been studied experimentally using a conductimetric stopped-flow technique. The experimental results indicate that this reaction follows a zwitterion intermediate mechanism leading to: $\text{k}{}_{\mathrm{obs}}\text{=}\text{[Am]}\text{1}\text{k}{}_2\text{+}\text{1}\text{k}{}_{\mathrm{Am}}\text{[Am] +}\text{k}{}_{\mathrm{w}}\text{[H}{}_2\text{O]}$ Values of the rate constants k₂, k_Am and k_w at 298 K are reported for both ethylenediamine and diethylenetriamine. Activation energies for k₂, k_Am and k_w are also reported for diethylenetriamine.