Synthesis of 1,1-Diphenylethylene (DPE): The Marriage of a Grignard Reaction and a Column Chromatography Experiment

The synthesis of 1,1-diphenylethylene (DPE) via a Grignard reaction, followed by an acid-catalyzed dehydration reaction, yields a mixture of compounds. DPE is a high boiling liquid that cannot be purified using simple distillation. However, it is easily separated from the more polar starting material and intermediate alcohol using both thin layer and column chromatography. Second-semester organic chemistry laboratory students learn the techniques of running reactions under anhydrous conditions and of column chromatography. In addition, the experiment demonstrates clearly the relationship between thin layer and column chromatography.