Perturbation of the oscillatory Belousov-Zhabotinsky reaction with polyethylene glycol

The effects of the water soluble non-ionic polymers poly(ethylene glycol) (PEG-400, PEG-900 and PEG-2000) and poly(ethylene glycol dimethylether) (MPEG-2000) on the dynamics of the cerium ion catalyzed oscillatory Belousov-Zhabotinsky (BZ) reaction were investigated in a stirred batch reactor by measuring CO2 evolution rate and Ce(IV) absorbance changes. Addition of increasing amounts of additives strongly influences all the oscillatory parameters (induction period, time period and amplitude) to an extent that depends on the type of the additive used. The polymer perturbation effects are compared with those previously obtained with methanol and ethylene glycol (1). All these experimental observations can be understood qualitatively by model calculations regarding i) the reactions of the alcoholic endgroups which generate the autocatalytic bromous acid and ii) the reactions of the polymer backbone which produce hypobromous and bromomalonic acids