The influence of coupled kinetic-equilibrium in breaking the correlation between kinetic parameters

Abstract The most important requirement in nonlinear model fitting is an approach to solve the problem concerning the determination of full correlated model parameters. Since nonlinear model-based analysis is used in the chemical process, the importance of this issue is further increased. For instance, it is challenging to uniquely measure the rate constants in first-order reverse reactions from incomplete concentration data. This is due to the correlation between these constants. Therefore, breaking this correlation is necessary to determine the rate constants. In this work, the coupled kinetic-equilibrium process is suggested as a new strategy to overcome this problem. Also, this fact allows for determining kinetic parameters in multi-step kinetic reactions. The model-based global analysis is a complete analysis of the complex reaction mechanisms with the possibility of calculating and inserting the equilibrium and kinetic parameters into the fitting algorithm. After the fitting process, the optimal equilibrium and kinetic parameters are obtained, along with an estimate of their standard deviations. Therefore, simulated data sets for a range of different chemical cases, as well as the pH-dependent keto-enol tautomerization are used to exemplify the methods.