Alternative Reaction Channels and Carbene Intermediates in the Ce4+ - Malonic Acid and Ce4+ - Bromomalonic Acid Reactions. 1. CO2 Measurements

Szilveszter Nagygyory, Mária Wittmann, Szilveszter Pintér, András Visegrády, András Dancsó, Nguyen Bich Thuy, Zoltán Noszticzius, Lászlö Hegedus, Horst Dieter Försterling

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

The Ce4+ - malonic/bromomalonic acid reactions play an important role in the oscillatory Belousov-Zhabotinsky reaction. In this work CO2 evolution from these reactions was studied with a sensitive and quantitative method, by converting the CO2 to methane and measuring it with a flame ionization detector. It was found that the stoichiometries depend on the initial conditions in batch experiments or on the mixing rate of reagents in a semibatch reactor. These findings are explained by two main reaction channels: one for recombination and another for decarboxylation. Decarboxylation itself has two separate routes, one is dominant at low while the other at high Ce4+ concentrations. In the latter, formation of more than two CO2 molecules from one malonic/bromomalonic acid molecule was observed. Novel reaction schemes containing carbenes are proposed for these "high Ce4+" decarboxylation channels. To check the new mechanism, HPLC measurements are planned as a continuation of the research.

Original languageEnglish
Pages (from-to)4885-4892
Number of pages8
JournalJournal of Physical Chemistry A
Volume103
Issue number25
DOIs
Publication statusPublished - Jun 24 1999

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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