Benzoin (0.5 g, 2.0 mmol) and ethanol (4.0 mL, 68.0 mmol) were added to a 25-mL Erlenmeyer flask and swirled gently at room temperature until fully dissolved. Sodium borohydride (0.1 g, 3.0 mmol) was added gradually over the course of five minutes using a microspatula, and the mixture was swirled at room temperature for twenty additional minutes. The mixture was cooled in an ice-water bath, then water (5.0 mL, 278.0 mmol) and 6M HCl (0.3 mL, 9.0 mmol) were added. After fifteen minutes, the mixture was quenched with another addition of water (2.5 mL, 139.0 mmol). The product was collected via vacuum filtration on a Hirsch funnel, allowed to dry on the filter for fifteen minutes, and the crude yield and melting points were recorded. Two milligrams of crude material were set aside for TLC analysis. The remaining crude material was recrystallized in a 25 mL Erlenmeyer flask using 6 drops of acetone. The final yield and melting point were recorded. Approximately two milligrams each of benzoin, the recrystallized product, and the reserved crude product were dissolved in ethyl acetate in three separate vials. The contents of the three vials were used to spot two TLC plates such that one plate contained benzoin, crude product and a combination of those two, while the other plate contained benzoin, recrystallized product, and a combination of those two. The TLC plates were run in 9:1 CH2Cl2:ethanol solution. The spots were visualized using short-wave UV light and an iodine chamber. The Rf values were calculated.
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