NEW SUBSTRATES IN THE FERROIN-CATALYZED BROMATE SYSTEM IN AQUEOUS-ORGANIC MIXED-MEDIA

A large number of substrates have hitherto been employed in the Belous ov-Zhabotinsky (B-Z) oscillatory system in pure aqueous medium. A syst ematic study of aromatic bromate oscillators is limited by solubility problem relating to the compounds and the brominated derivatives. The use of aqueous-organic mixed media for the oscillatory study is found to be highly useful for the study of water insoluble substances. A com parative study of the oscillatory behavior of gallic acid as substrate in pure aqueous as well as in a number of mixed media have been made in order to ascertain the suitability of mixed media in oscillatory sy stems. The alteration of oscillatory characteristics in the presence o f organic solvent can be understood in terms of the Field-Koros-Noyes (FKN) mechanism. The oscillatory behavior of seventeen new substrates in the ferroin-catalyzed bromate system in 20% (v) acetonitrile is als o presented and discussed in this communication. The reactivity of str ucturally related substrates has been correlated to the structure in t erms of the relevant oscillatory parameters. The use of aqueous-organi c mixed media in oscillatory systems would enable the investigation of new classes of substrates since getting them into the solution phase would no longer be a limitation.