Simultaneous calorimetric and potentiometric investigations on some uncatalyzed bromate oscillators (UBOs)

Simultaneous calorimetric and potentiometric/thermometric measurements were performed on three uncatalyzed bromate oscillators (UBOs) showing distinct temporal structures. The following UBOs were chosen: a) the gallic acid (3 ,4,5-trihydroxy benzoic acid)-bromate; b) the 1-hydroxy-4-[(1-hydroxy-2-met hylamino)ethyl] benzene (HME)-bromate; and c) the 1,4-cyclohexanedione (CHD )-bromate system. Their oscillating reactions were monitored by an isoperib olic batch calorimeter of the Calvet-type at 20 degrees C and with a quasi- adiabatic Dewar setup at room temperature, and in addition by platinum/calo mel potentiometry and thermometry. Shape of the calorimetric curves, number and duration of the oscillations and their frequencies varied considerably between these three UBOs. The underlying chemical reaction schemes are dis cussed in connection with the energetic background.