Resumen de GC/MS of Unknown Esters for Teaching MS Fragmentation Patterns:: A Combination Organic Experiment for Esterifying Unknown Alcohols and Determining their Structures by GC/MS

Ernest C. McGoran, Cameron Melton, Darren Taitch

• Students receive an unknown (pentanol, tert-pentanol, neopentanol, or isopentanol) and prepare its acetate using acetyl chloride in the presence of polymer-bound DMAP, a super-acylation catalyst. The structure of the ester product is determined from the MS, obtained using a GC/MS instrument. Rules for the MS fragmentation of acetates are compiled and illustrated by equations. Students work together in groups of three to match fragmentation rules with actual MS data to identify each of three different unknowns, assigned individually for the conversion of their acetates.