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M. K. Beklemishev, I. V. Nikolaev, L. Yu. Belyaeva
Radical
Polymerization Reactions as Indicators for the Determination of Organic
Compounds
Abstract
Polymerization
of methyl methacrylate (MMA) or 4-vinylpyridine (VP) was conducted in an aqueous solution in the
presence of tetramethylethylenediamine (TEMED) – persulfate initiating system. The
reaction rate was monitored turbidimetrically by the polymer suspension
formation with and without 26 model organic compounds. Less number of the
compounds inhibit the polymerization of VP (9 compounds) than that of MMA (22 compounds) which signifies
better selectivity of the first reaction; at the same time, the determination
of the model compounds by the MMA polymerization reaction is more sensitive. This was explained by a
lower chain growth rate constant for VP vs. MMA and a difference in the stationary
concentrations of radicals. Some closely related compounds can be
discriminated, e.g., 1,4-benzoquinone from 9,10-anthraquinone (using the
MMA reaction) and di-
or trinitrophenol from phenol or 4 nitrophenol (using the VP reaction).
Determination of ascorbic acid in a pharmaceutical formulation has been
performed.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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