HIGH- AND LOW-TEMPERATURE MECHANISMS IN THERMAL DECOMPOSITION OF ACETIC ACID

The homogeneous thermal decomposition of acetic acid has been studied between 530 and 762° in a flow system. Below 600° dehydration is second-order: k = 109.52 exp(-39.300/RT) l. mole-1 sec.-1, but the order falls and the Arrhenius plot curves upwards above this temperature. Above 700°, the process is first-order: k=10 12.45 exp(-64.890/RT) sec.-1. Decarboxylation, however, is first-order throughout the range: k=1013.59 exp(-69,800/RT) sec.-1. All processes are molecular.