Acid Autocatalysis Best Served Hot: The Chlorate-Sulfite-Gluconolactone System as a Thermochemical Clock

The autonomous activation of acid-autocatalyzed sulfite-halogenate (iodate, bromate, chlorate) reactions is programmed using slow acid generators (delta-gluconolactone GL, and 1,3-propanesultone PrS). A remarkable correlation is found between the pH- and temperature-time profiles, especially for the chlorate-sulfite-GL system. Further optimization of the latter resulted in a chemical system able to generate sudden temperature and pH changes after a tailorable induction time, that is a "thermochemical clock".