Eyringformler

Eyringformler, also known as Eyring equations or Eyring-Polanyi equations, are a set of fundamental equations in chemical kinetics and physical chemistry that describe the rate of chemical reactions. Developed by Henry Eyring and others, these equations relate the rate constant of a reaction to thermodynamic properties of the transition state, a high-energy intermediate structure through which reactants must pass to form products. The core concept behind the Eyringformler is that a reaction proceeds through an equilibrium between reactants and this transition state.

The most widely used form of the Eyring equation is derived from transition state theory. It states that the rate constant k is proportional to the temperature T and inversely proportional to the Planck constant h and the Boltzmann constant kB. The proportionality factor involves the activation Gibbs free energy, which is composed of enthalpy and entropy of activation. Specifically, the equation relates the rate constant to the partition functions of the activated complex and the reactants. This formulation allows for the prediction of reaction rates based on theoretical calculations or experimental determination of the thermodynamic parameters associated with the activation process.

The Eyringformler have been instrumental in understanding reaction mechanisms and predicting reaction kinetics. They find applications in diverse fields, including organic chemistry, physical chemistry, and materials science, where understanding and controlling reaction rates are crucial. While providing a powerful theoretical framework, their application often relies on approximations, particularly concerning the nature of the transition state and the validity of the equilibrium assumption.