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Theoretical Study of Reactions between Oxygen‐Centered Radicals ( • OH and SO 4 •— ) and Vinyl Monomers in Aqueous Phase
Author(s) -
MartinezDe la Hoz Julibeth M.,
Konstantinov Ivan A.,
Arturo Steven G.,
Dombrowski Gary
Publication year - 2016
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/mats.201600023
Subject(s) - radical , monomer , vinyl acetate , chemistry , methacrylate , methyl methacrylate , acrylate , polymerization , gibbs free energy , methyl acrylate , emulsion polymerization , polymer chemistry , polymer , computational chemistry , thermodynamics , organic chemistry , copolymer , physics
In this work, reactions between industrially relevant monomers (methyl acrylate, ethyl acrylate, methyl methacrylate, vinyl acetate, and isopropenyl acetate) and oxygen‐centered radicals ( • OH and SO 4 •— ) are studied using a combination of quantum mechanics and transition state theory. These reactions may have a strong influence on polymer structure and properties. Thus, computational methodologies able to estimate reliably coefficients for these reactions are needed to improve the understanding of emulsion polymerization processes. In the case of reactions involving • OH, the computational approach is based on the SMD‐water/M06‐2X/6‐311++G(3df, 2p)//B3LYP/6‐31+G(d, p) DFT scheme. All calculated and experimental Gibbs free energy barriers, | Δ G exp ≠ − Δ G calc ≠ | , are within 1 kcal mol −1 . In the case of reactions involving SO 4 •— , the SMD‐water/M06‐2X/6‐311++G(3df, 2p)//CAM‐B3LYP/6‐31+G(d, p) DFT scheme is found to be more suitable than a similar scheme based on B3LYP. This proposed scheme works well for acrylates and methacrylates (errors within 1 kcal mol −1 ), but it may overestimate the rate coefficients of acetates reacting with SO 4 • — .