Journal article
Computational study of the self-initiation mechanism in thermal polymerization of methyl acrylate
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, v 113(40), pp 10787-10794
08 Oct 2009
PMID: 19791812
Abstract
This computational study deals with the mechanism of spontaneous initiation in thermal polymerization of alkyl acrylates (e.g., methyl, ethyl, and n-butyl acrylate). The mechanism is presently still unknown. Density-functional theory (DFT) and Møller-Plesset (MP2) calculations are used to explore the Flory and Mayo mechanisms of self-initiation in methyl acrylate. On the singlet surface, a low-barrier, concerted [4 + 2] Diels-Alder mechanism for the formation of a dihydropyran adduct (DA) and a high-barrier nonconcerted [2 + 2] diradical ((*)M(2s)(*)) mechanism for the formation of dimethyl cyclobutane-1,2-dicarboxylate (DCD) were found using B3LYP/6-31G*. Several levels of theory were used to validate the transition states, and the pathways for the DA and DCD formations on the singlet surface were determined using intrinsic reaction coordinate (IRC) calculations. On the triplet surface, a triplet diradical intermediate ((*)M(2t)(*)) was identified that is structurally similar to (*)M(2s)(*) but lower in energy. The spin-orbit coupling constant for crossover of the diradical from singlet to triplet surface was calculated. Monoradical generation from the two intermediates, DA and (*)M(2t)(*) via hydrogen transfer to or from a third methyl acrylate was studied. It was found that generation of two monoradical species was possible from (*)M(2t)(*) and is proposed as a likely explanation for experimentally observed spontaneous-initiation.
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Details
- Title
- Computational study of the self-initiation mechanism in thermal polymerization of methyl acrylate
- Creators
- Sriraj Srinivasan - Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USAMyung Won LeeMichael C GradyMasoud SoroushAndrew M Rappe
- Publication Details
- The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, v 113(40), pp 10787-10794
- Publisher
- American Chemical Society; Washington, DC
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Chemical and Biological Engineering
- Web of Science ID
- WOS:000270362900024
- Scopus ID
- 2-s2.0-70349686762
- Other Identifier
- 991014878315004721
InCites Highlights
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- Collaboration types
- Industry collaboration
- Domestic collaboration
- Web of Science research areas
- Chemistry, Physical
- Physics, Atomic, Molecular & Chemical