Calorimetric Determination of Rate Constants and Enthalpy Changes for Zero-Order Reactions

Abstract

Calorimetry is a general method for determination of the rates of zero-order processes, but analysis of the data for the rate constant and reaction enthalpy is difficult because these occur as a product in the rate equation so evaluation of one requires knowledge of the other. Three methods for evaluation of both parameters, without prior knowledge, are illustrated with examples and compared with literature data. Method 1 requires the reaction to be studied in two buffers with different enthalpies of ionization. Method 2 is based on calculation of reaction enthalpy from group additivity functions. Method 3 applies when reaction progresses to completion. The methods are applied to the enzymatic hydrolysis of urea, the hydrolysis of acetylsalicylic acid, and the photodegradation of nifedipine, respectively.

Thermodynamic Consistency and Kinetic Mechanism of a Complex Reaction Pathway by Analysis of Its Constituent Cyclic Networks

“…Kinetic analysis of chemical reaction networks typically involves solving the underlying system of differential equations to determine species concentrations. − Modeling of complex reaction networks is of particular interest in this domain and has been widely explored in previous works. − Several studies have used a combination of kinetic and thermodynamic approaches to quantify the overall rates of cyclic reaction systems. ,,,− …”