Premium
Relevance of backbiting and beta‐scission reactions in the free radical polymerization of Acrylonitrile
Author(s) -
Dossi M.,
Storti G.,
Moscatelli D.
Publication year - 2010
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200900013
Subject(s) - chemistry , radical , acrylonitrile , activation energy , polymer chemistry , beta scission , polymerization , reaction rate constant , polymer , kinetics , organic chemistry , radical substitution , physics , quantum mechanics , copolymer
Summary: In this work, backbiting and beta‐scission reactions are investigated through Quantum Chemistry methods by adopting the Becke 3 parameters and Lee Yang Parr functional (B3LYP) and 6‐31G(d,p) basis set. Namely, the 1:3, 1:5 and 1:7 backbiting reactions are studied for acrylonitrile polymerization. It was found that the backbiting 1:5 is the most favorited because this kinetic event leads to the formation of a 6 membered transition state, while the backbiting 1:3 requires high activation energy due to the formation of a highly strained 4 membered ring. 7:3 backbiting reaction was also examined, since it is an alternative pathway that can explain the formation of defects generated by radicals in the third position. Simulations showed that this kinetic step is characterized by high rate constant because of its low activation energy. The right and left beta‐scission reactions from the mid chain radicals formed by the considered backbiting reactions are also studied. Computational analysis demonstrated that all beta‐scission reactions are endothermic and both the right and left beta‐scission reactions have the same activation energy, which seems to be more influenced by the position of the mid chain radical.