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.
