Kinetic study of the Ce(III)-, Mn(II)-, or ferroin-catalyzed Belousov-Zhabotinsky reaction with pyruvic acid

Abstract

rates of bromination reactions of pyruvic acids are independent of the concentration of bromine and the order of reactivity toward bromination is (DPA1, DPA2) Ͼ BrPA Ͼ PA. Experimental results are rationalized.

Chemical Equilibria and Kinetics in Aqueous Solutions of Zymonic Acid

“…The fastest interconversion appears to be between the cyclic and acyclic ketone forms of zymonic acid (ZCK and ZOK) on the subsecond time scale. This rate of interconversion increases with increasing pH, which has caused the mixture of these two substances to be misidentified as a single substance in previous literature. − The slower kinetic interconversions in water indicate the direct transition from an enol to a geminal diol (ZCE to ZCD) without a ketone intermediate. A kinetic fit was performed that reinforces the validity of this observation.…”

“…At equilibrium under low pH conditions, we detect and assign five different forms of pyruvic acid dimers in solution and investigate the mechanisms of their interconversion. Our higher resolution NMR work across a broader pH range allows for the differentiation of quickly exchanging species that were assigned to single components in most previous works. − We report identification and characterization of the pyruvic acid chemical dimerization products followed by a study of the kinetics of interconversion. Finally, potential mechanisms are discussed for the novel interconversions that are observed.…”

“…Later studies are split between work examining metal catalysis − and biological processes. − Zymonic acid was identified as a metabolite in yeast, only to be shown to be a contaminant from pyruvic acid used, and an incorrect structure was first reported. , A number of other papers have discussed the detection or role of parapyruvic and zymonic acid in various biological contexts, including detection from living tissues and interactions with enzymes. − Interestingly, parapyruvic acid has been observed in meteorites alongside pyruvic acid and discussed in the context of the origin of life . There are several papers discussing the spontaneous formation of zymonic and parapyruvic acids from pyruvic acid under different conditions, which suggest that these molecules exist as contaminants in other experiments. ,− Because these dimerization products are formed relatively easily, it is somewhat unclear whether previous detections of zymonic and parapyruvic acids are artifacts of the analytical techniques that were used.…”

Mechanism and Phenomenology of an Oscillating Chemical Reaction

“…The reaction products were found to be BrMeMA and acetic acid (AcA), in the ratio 2:3 respectively, exactly as was predicted by FKN for MA. Jwo and others have investigated the kinetics of ethyl-, butyl-, phenyl-malonic acids, and many similar species [79][80][81][82][83]. These acids are less reactive than MA with Ce 4+ , and typically form less reaction products.…”