Thermodynamic and Stochastic Theory for Nonequilibrium Systems with More Than One Reactive Intermediate: Nonautocatalytic or Equilibrating Systems.

摘要

Consider chemical reactions occurring in a compartment separated by semipermeable membranes from reservoirs of reactant and product, both held at constant pressure. Earlier work, developed a nonequilibrium thermodynamic theory applicable to systems with a single reactive intermediate, and established a link between the thermodynamic and stochastic analyses of such systems. Here results generalize directly to cases with two or more reactive intermediates, if the reaction mechanism is nonautocatalytic, or if the system is evolving toward and equilibrium steady state in the reaction compartment without first exhausting the reactant or product reservoir. Start with nonautocatalytic mechanisms, identify effective driving forces for each intermediate; then obtain the driving force for an arbitrary system by mapping to an instantaneously equivalent nonautocatalytic system. Taking the product of the driving force and the net flux of each intermediate and then summing over the species gives a term in the dissipation that is specific to the intermediates. This term is minimized at nonequilibrium steady states, unlike the total dissipation (or entropy production). For the nonautocatalytic or equilibrating systems, an integral of the driving forces yields a Liapunov function for the evolution of the reaction chamber toward the steady state. The same integral also determines the stationary solution of the birth-death master equation for the species numbers of intermediates in the reaction compartment. Reprints.