Measurement of the trapping rate constants and product studies of quinone derivative inhibitors with phenethyl radicals
Park, Hee Jung
Engel, Paul S.
Master of Arts
Styrene is one of many industrially important monomers. Polymerization of unsaturated monomers such as styrene is a troublesome problem during storage, transportation and processing. The problem is attenuated by addition of polymerization inhibitors such as quinone derivatives. Despite the importance of quinone type inhibitors, their chemistry is poorly understood. The goal of this research is to better understand the reaction mechanism and rates of alpha-phenethyl radicals with quinone type inhibitors. cis Azo-alpha-phenylethane was used as a new simple, unimolecular, low temperature source of alpha-phenethyl radicals. The absolute rate constants of five quinone type inhibitors (N-oxide, BQ, QM, tBQ and DPQI) with alpha-phenethyl radicals generated from cis azo-alpha-phenylethane were measured by the radical clock method using the stable nitroxide SG1 as the clock. We found that the trapping rate decreased in the order N-oxide>BQ>QM>tBQ>DPQI. Also product studies of BQ and QM with phenethyl radicals were done to augment previous results.