The imidazole catalysed hydrolysis of triacetin: an inter- and intra-laboratory development of a test reaction for isothermal heat conduction microcalorimeters used for determination of both thermodynamic and kinetic parameters

Abstract

This paper reports the outcomes of an inter- and intra-laboratory microcalorimetric investigation of the triacetin hydrolysis reaction in an imidazole/acetic acid buffer system. The purpose was to establish whether this reaction would be an appropriate test reaction system for validation of isothermal heat conduction microcalorimeters used to determine both thermodynamic and kinetic data. To be acceptable for this purpose a reaction should be simple to perform, robust in operation, undemanding with respect to sources of chemicals, operators, calorimeters and their operating procedures (within defined limits). The reaction system studied is shown to fulfil these criteria. For this second-order reaction, performed at 298 K the recommended values for the reaction rate constant, k, and the enthalpy change, Δ R H, are: k=2.80±0.10×10 −6 dm 3 mol −1 s −1; Δ R H=−91.7±3.0 kJ mol −1 .