A new rationale of reaction metrics for green chemistry. Mathematical expression of the environmental impact factor of chemical processes

A rationale of reaction metrics for green chemistry is presented, along with relationships between them. Starting from the definition of mass intensity, it is easy to find the mathematical formula giving the reaction metrics, such as the E-factor, versus the parameters of a reaction sequence: yields of each step, atom economy, excess of reactants, mass of auxiliaries and possibly their retrieval. For a complex mixed linear and convergent sequence, such a rationale could be expressed with a mathematical formula as simple as eqn (24). Based on experimental data, the application of such a methodology was proved to be useful to quantify the influence of each parameter of a chemical process on the environmental impact.