An Efficient Microkinetic Modeling Protocol: Start with Only the Dominant Mechanisms, Adjust All Parameters, and Build the Complete Model Incrementally

In a recent article (ACS Catal. 2018, 8, 11119-11133), a comprehensive catalytic mechanism is proposed to explain the effects of residual water on the reactivity and regioselectivity of tris(pentafluorophenyl)borane catalyst in the ring-opening reaction of 1,2-epoxyoctane by 2-propanol. Using it as a representative example of a common trend followed also by other groups, we show that the heavily under-constrained (loose) kinetic modeling approach employed can lead to several pitfalls and propose an alternative, more stringent (tight) modeling protocol to avoid them. In addition to providing similar or better accuracy, this approach considerably reduces the DFT parameter calculation time (by a factor of 10 in the present case). We also show an example of how delayed or second-order mechanisms can then be added incrementally to the already built and tested, first-approximation model to achieve a highly predictive and comprehensive microkinetic model. We hope that this simple and robust microkinetic modeling protocol may contribute to the current efforts to establish new, more predictive computational methodologies for synthetic chemistry.