Stable and Unstable Concentration Oscillations Induced by Temperature Oscillations on Reversible Nonequilibrium Chemical Reactions of Helicene Oligomers

Temperature oscillations can affect behaviors of living things. In this article, we describe the effect of triangle temperature oscillations on reversible nonequilibrium chemical reactions detected as concentration oscillations. When amplification through self-catalytic reactions is involved in the chemical reactions, concentration oscillations exhibit diverse nonequilibrium phenomena, which include equilibrium intersecting, equilibrium noncontact, and equilibrium sliding. Both stable and unstable concentration oscillations occur, during which repeated cycles provide the same and different concentration oscillations, respectively. Concentration oscillations are classified according to their waveforms in concentration/time profiles, the shapes of hysteresis curves in concentration/temperature profiles, the nature of self-catalytic reactions, and their relationships with equilibrium. An unstable concentration oscillation may be transformed into a stable concentration oscillation, which is described on the basis of the classifications. Experimental examples are shown using reversible association and dissociation reactions of helicene oligomers.

Automated summary

In this article, the effect of triangle temperature oscillations on reversible nonequilibrium chemical reactions is described. The concentration oscillations exhibit diverse nonequilibrium phenomena, including equilibrium intersecting, equilibrium noncontact, and equilibrium sliding, when self-catalytic reactions are involved. Both stable and unstable concentration oscillations occur, and they are classified based on the waveforms in concentration/time profiles, hysteresis curves in concentration/temperature profiles, nature of self-catalytic reactions, and their relationships with equilibrium. Experimental examples using reversible association and dissociation reactions of helicene oligomers are shown.