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The work pertains to the study on direct and indirect interaction of a macroporous weak acid cation exchange resin‐Dowex Mac 3H form with Belousov‐Zhabotinsky (BZ) reaction based on malonic acid‐cerium‐bromate‐sulfuric acid system. In the direct mode, the above reaction was perturbed by adding 10% (w/w) of Dowex Mac 3H at three different time intervals, i. e., before the start of induction period, during the induction period and after the commencement of oscillations. This mode of interaction was studied to investigate the effect of heterogeneity on the dynamics of BZ reaction. The indirect interaction of the resin was studied by interacting the resin individually with the optimized metal catalyst for a particular period of time after which the supernatant was used as initial reagent in the otherwise optimized BZ system. The interaction was monitored with respect to the change in oscillatory parameters before and after loading the resin with metal catalyst. The selectivity of the resin towards cerium and iron (ferroin) was studied through the said BZ reaction using potentiometry as the main technique. It was found that resin is more selective towards ferroin. The selectivity of the resin towards the various metal ions was followed by their estimation using UV‐Visible spectrophotometry. The effect of solvents on the ion exchange capacity (IEC) of the resin was also studied through the BZ reaction. Some solvents increased its IEC while others decreased it. The potentiometric results obtained were validated by spectroscopic findings and electrochemical studies. [ABSTRACT FROM AUTHOR]

Abstract: Effect on the behavior of Tyrosine through a malonic acid (MA) based Briggs‐Rauscher (BR) oscillatory system was studied in order to understand the mechanistic details of thyroid metabolism in vitro, specifically the iodination of tyrosine. It was observed that the present BR system employing tyrosine as a main additive and malonic acid as substrate provides an example of entrainment oscillations, in which malonic acid is responsible for oscillations and in presence of tyrosine, the system showed different oscillatory behavior. The effects of various other chemical species such as SeO2, KSCN, KNO3, KBr and Fe(III) on the tyrosine in this malonic acid based BR system are studied. The study was supported by UV‐Visible spectrophotometry to study the interactions of these chemical species with Dushmann reaction, which is one of the important reaction steps in BR reaction mechanism, in order to investigate the key factors responsible for tyrosine iodination responsible for thyroxin formation. Needless to mention that, all the aforesaid chemical species have due role in normal thyroid metabolism in vivo and as such, the present BR system containing tyrosine as main (first) additive can help in understanding of thyroid metabolism. [ABSTRACT FROM AUTHOR]