THE 1,4-CYCLOHEXANEDIONE-BROMATE-ACID OSCILLATORY SYSTEM - 3 - DETAILED MECHANISM

1,4-Cyclohexanedione (CHD) in its reaction with acidic bromate undergo es aromatization and one of the main resulting products 1,4-dihydroxyb enzene (H(2)Q) is further oxidized and brominated to 1,4-benzoquinone and bromoorganics. The kinetics of H(2)Q formation, of the reaction of CHD and Br-2, as well as of the reaction between H(2)Q and bromate io n, were followed spectrophotometrically. The latter reaction exhibited Landolt (clock)-type dynamics. On the basis of our earlier analytical and present kinetic investigations, a detailed mechanistic model has been suggested that could well simulate the temporal oscillations of t he title system. H(2)Q plays an essential role in the mechanism and is responsible for the unusual behavior (200-300 oscillations) of this c hemical oscillator. We pointed to the relation that may exist between the CHD-bromate-acid system and those reported as oscillatory Landolt- type reactions [e.g., IO3- - SO32- - Fe(CN)(6)(4-)].