In this lab, benzoin (0.5 g), ethanol (4 mL), and sodium borohydride (0.1 g) were reacted at room temperature. This reaction dehydrated benzoin into 1,2-diphenylethane-1,2-diol. The product was recrystallized and tested through thin layer chromatography (TLC) to observe if the product was present. The target product was obtained at 14%.
After the reaction occurred, the crude product obtained, 1,2-diphenylethane-1,2-diol, weighted 0.378 g and had a melting point of 136-138 ℃. This melting point was lower than expected due to the impurities that may be present. The impurities may be present because the reaction was not carried out completely. The incomplete reaction may be a result of potentially adding the sodium borohydride too quickly, not swirling the solution enough, or not allowing the reaction to occur in an adequate amount of time.
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