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The Importance of Mesomerism in the Termination of α ‐Carboxymethyl Radicals from Aqueous Malonic and Acetic Acids
Author(s) -
Wang WenFeng,
Schuchmann Man Nien,
Schuchmann HeinzPeter,
von Sonntag Clemens
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010216)7:4<791::aid-chem791>3.0.co;2-2
Subject(s) - radical , chemistry , decarboxylation , acetic acid , malonic acid , protonation , aqueous solution , hydrogen atom abstraction , photochemistry , medicinal chemistry , organic chemistry , catalysis , ion
In the dioxygen‐free aqueous malonic and acetic acid systems, α ‐carboxymethyl radicals are produced through hydrogen abstraction from the parent compound by radiolytically generated OH radicals. H abstraction from the CO 2 − /CO 2 H group followed by decarboxylation is a process of small importance (≤5 %). The α ‐carboxymethyl radicals terminate by recombination. Two types of recombination product are observed which are characterised by the formation of a C−C linkage or a C−O linkage. α ‐Carboxymethyl radicals are mesomeric systems. Their mesomeric state depends on the state of protonation and determines the proportion of the C−C‐ versus C−O‐linked dehydrodimers they produce.