Belousov-Zhabotinsky oscillations in bromate-oxalic acid-MnSO4-H2SO4-acetone system in nonionic surfactant medium. A calorimetric study

Thermal oscillations in oxalic acid-bromate-MnSO4-H2SO4- acetone system hav e been studied in aqueous solution of nonionic surfactants, TX-100, Tweens (20, 40, and 60), and Brijs (56, 58 and 76). It has been observed that sign ificantly low concentration of the surfactants can inhibit the oscillatory reaction. In general, they have inhibitory effects on the frequency and ent halpy of oscillations. The inhibition has been found to have direct depende nce on the length of the nonpolar tail of the surfactant molecule. There is a threshold concentration for a surfactant above which oscillation stops, and this threshold or critical concentration decreases with increasing leng th of the surfactant chain. The amphiphile n-heptanol has also shown signif icant inhibitory effect.