Reactions of keten. Part IV. Kinetics and thermodynamics of the gas-phase reaction: thioacetic acid + keten ⇆ acetic thioanhydride
Abstract
The homogeneous gas-phase reaction CH3COSH + CH2:CO ⇆ Ac2S has been studied in both directions over the temperature range 128–253°. The forward reaction is of the second order, k= 105·45 exp (–37,900/RT) l mol–1 s–1, and the back reaction first order, k= 1011·02 exp (–131,000/RT) s–1. Equilibrium constants were measured starting from both sides of the reaction, and calculated from the ratio of the rate constants. From the mean of these was obtained ΔH°=–94·7 kJ mol–1 and ΔS°=–140·8 J K–1 mol–1. Results are compared with those obtained for the keten–acetic acid system.