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

This paper reports the outcomes of an inter- and intra-laboratory microcalo rimetric investigation of the triacetin hydrolysis reaction in an imidazole /acetic acid buffer system. The purpose was to establish whether this react ion would be an appropriate test reaction system for validation of isotherm al heat conduction microcalorimeters used to determine both thermodynamic a nd kinetic data. To be acceptable for this purpose a reaction should be sim ple 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 crite ria. For this second-order reaction, performed at 298 K the recommended val ues for the reaction rate constant, k, and the enthalpy change, Delta H-R, are: k = 2.80 +/- 0.10 x 10(-6) dm(3) mol(-1) s(-1); Delta H-R = -91.7 +/- 3.0 kJ mol(-1). (C) 2001 Elsevier Science B.V. All rights reserved.