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Jordan Bobek, Dr. Steven W. Anderson, Department of Chemistry, University of Wisconsin-Whitewater, 800 West Main Street, 269 Wyman Mall, Whitewater, WI 53190
Photoinititators are compounds that readily absorb UV light and are converted into reactive intermediates like free radicals and acids. They are used to initiate polymerization reactions. Photoinitiators find many applications such as coatings, adhesives, dental resins, gel nail polish, and inks. Our focus is to prepare new substituted phenyl indandiones by a Dieckman reaction between substituted benzaldehydes with electron donating and electron withdrawing substituents (e.g., –NO2, -CH3 and -OCH3). These will be examined for how they affect the efficiency of the sulfonium salt photoinitiators synthesized. 2-(p-Bromophenyl)-1,3-indandione, was synthesized by a Dieckman reaction of p-bromobenzaldehyde and pthalide with sodium methoxide and dried methanol under nitrogen. Water was added after reflux and the alcohol removed. Vacuum filtration afforded dark purple crystals which were recrystallized with chloroform. White crystals were collected via vacuum filtration which left the desired final product. IR and NMR analysis of the crystals were performed to test purity. Column chromatography (silica gel/acetone-pet ether) was used to help further purify the crystals. A p-bromo substituent in the phenyl ring of the indandione sulfonium salt is expected to increase the rate of the reaction while other electron-donating substituents should decrease the rate. 1,3-Indandione, 2-(4-methylphenyl) was also synthesized using the same Dieckman reaction with p-tolualdehyde, pthalide, sodium methoxide and dried methanol under nitrogen. Evaluation of the substituent effects of the sulfonium salt with these para substituents will be done by studying the kinetics of photodecomposition and comparing the results to standard photoinitiators. To our knowledge, synthesis and polymerization studies of photoinitators in green solvents has only recently been discovered. Comparisons will be made with these compounds and related ones to be found in the literature.
Presenter: Jordan Bobek
Institution: University of Wisconsin - Whitewater
Type: Poster
Subject: Chemistry
Status: Approved
