Dynamic modeling of reaction pathways on the Gibbs energy surface

Based on irreversible thermodynamics and kinetic rate theory developed a nu mber of years ago, modern computer graphics provide new methods to optimize selectivity in multiple reactors or single reactions with multiple reactio n mechanisms. Initial conditions and standard Gibbs energies of reaction ar e sufficient to provide a Gibbs energy surface as a function of reaction ex tents for the rate-limiting reactions. These conditions also provide the Ki netic boundaries, as defined here on the extent plane, over which reaction pathways cannot cross. However, product yields higher than those at equilib rium can, nevertheless, be achieved within the kinetic boundaries in some c ases. The industrial term for this feat, cheating thermodynamics, is shown to be incorrect. For simplicity the results presented are for perfect gas m ixtures under isobaric/isothermal reaction conditions; other cases are cite d. Last, electrical analogue diagrams for complex reaction systems and the meaning of the term rate limiting are considered.