Solid–gas reactions. Part II. Solid-state cis–trans isomerisation of alkoxycinnamic acids in iodine vapour
The cis–trans isomerisation of solid o-alkoxy-cis-cinnamic acids by iodine vapour has been analysed by determination of the rate of the reaction from the change in i.r. transmittance. The isomerisation follows a first-order mechanism. The energy of activation for the isomerisation increases with the density of the solid material. A plot of ΔH‡ against ΔS‡ is linear.