Microcanonical modeling of the thermokinetic method

Area of Science:

• Physical Chemistry
• Chemical Kinetics
• Computational Chemistry

Background:

• The thermokinetic method is crucial for analyzing reaction rates.
• Understanding proton transfer is fundamental in chemical reactions.
• Statistical rate calculations and transition state theory provide theoretical frameworks.

Purpose of the Study:

• To perform a microcanonical analysis of the thermokinetic method for proton transfer.
• To model the proton transfer process MH(+) + B(i) --> M + B(i)H(+).
• To investigate reaction efficiency as a function of zero-point energy differences.

Main Methods:

• Utilizing statistical rate calculations based on orbiting transition state theory.
• Performing microcanonical analysis of the thermokinetic method.
• Simulating reactions with varying entropic losses upon protonation.

Main Results:

• Reaction efficiency is dependent on the zero-point energy difference between reactants and products.
• The standard thermokinetic method accurately predicts gas-phase basicities (GB(298)(M)) at 298 K, even for complex molecules.
• Proton affinity (PA(298)(M)) and protonation entropy can only be determined under specific conditions, such as variable temperature experiments.

Conclusions:

• The thermokinetic method is reliable for gas-phase basicity determination at 298 K.
• Accurate determination of proton affinity and entropy requires experimental adjustments, like temperature variation.
• The study highlights the nuances of applying kinetic methods to complex chemical systems.