sodium borohydride procedure

0.515 grams of Benzoin and 4 mL of ethanol were added to a 25 mL flask and swirled until fully dissolved. 0.10 grams of sodium borohydride was added over a 5-minute period and swirled for 20 minutes at room temperature. The mixture was then cooled in an ice bath. 5 mL of distilled water and 0.3 mL of 5M HCl was added to the mixture. After 15 minutes an additional 2.5 mL of distilled water was added to the sample and the product was collected via vacuum filtration. The product was dried on the filter paper for 15 minutes. The yield and melting point of the crude product was determined. The crude product was then recrystallized from acetone in a flask and the crystals were allowed to dry before the melting point and mass of the purified 1,2-diphenylethan-1,2-diol were determined. After recrystallization a small amount of the starting material (benzoin), the crude product, and the recrystallized product were all dissolved individually in vials with ethyl acetate. Two TLC plates were spotted. One TLC plate was spotted with the starting material, the recrystallized product, and a mixture of the starting material and the recrystallized product. The second TLC plate was spotted with the starting material, the crude product, and a mixture of the starting material and the crude product. Both TLC plates were run in a 9:1 CH₂Cl₂ : ethanol and then analyzed.