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Thermal decomposition of potassium persulfate in aqueous solution at 50°C in the presence of ethyl acrylate
Author(s) -
Adhikari Mukti Sadan,
Sarkar Swati,
Banerjee Monoranjan,
Konar Ranjit Singha
Publication year - 1987
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1987.070340110
Subject(s) - potassium persulfate , thermal decomposition , monomer , aqueous solution , persulfate , chemistry , decomposition , polymerization , ammonium persulfate , acrylate , analytical chemistry (journal) , inorganic chemistry , polymer , organic chemistry , catalysis
Potassium persulfate modes of thermal decomposition and reactions with ethyl acrylate in aqueous solution at 50°C in nitrogen atmosphere have been investigated. It has been found that the rate of persulfate decomposition may be expressed as − d (S 2 O 8 2− )/ dt ∝ (S 2 O 8 2− ) 1.00 ± 0.06 × (M) 0.92±0.05 while the steady state rate of polymerization ( R p ) is given by R p ∝ (S 2 O 8 2− ) 0.50 ± 0.50 × (M) 1.00 ± 0.06 in the concentration ranges of the persulfate, 10 −3 −10 −2 (m/L), and monomer (M), 4.62−23.10 × 10 −2 (m/L), i.e., within its solubility range. In the absence of monomer, the rate of persulfate decomposition was slow and first order in persulfate at the early stages of the reaction when the pH of the solution was above 3.0. The separating polymer phase was a stable colloid at low electrolyte concentrations even in the absence of micelle generators. It has been shown that the oxidation of water soluble monomeric and oligomeric radicals by the S 2 O 8 2−ions in the aqueous phase, viz., \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm M}_j^ \cdot + {\rm S}_2 {\rm O}_8^{2 - } \to {\rm M}_j - {\rm O} - {\rm SO}_3^ - + {\rm SO}_4^{ \cdot - } $\end{document} is not kinetically significant in this system. It has been found that the reaction \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm M} + {\rm S}_2 {\rm O}_8^{2 - } \rightarrow{k}{\rm M} - {\rm O} - {\rm SO}_3^ - + {\rm SO}_4^{ \cdot - } $\end{document} would also lead to chain initiation at the outset of the polymerization reaction. k has been estimated as 5.41 × 10 −5 (L/m/s) at 50°C. Taking k p as 10 3 (L/m/s), k t has been estimated as 0.168 × 10 6 (L/m/s). The partition confficient (β) of the monomer between the polymer phase and the aqueous phase was found to be 16 ± 2, at 50°C. The rate constant for persulfate ion dissociation has been found as 1.40 × 10 −6 s −1 at 50°C.