Procedure

The first step is to add benzoin (0.5 g) and ethanol (4 ml) to an Erlenmeyer flask and swirl gently until it’s fully dissolved. Then, add sodium borohydride (0.1g) in small amounts over a 5-minute time period. After all of it is added gently swirl for twenty minutes. Once the compound is mixed thoroughly cool it in an ice-bath and add water (5 mL) and 6M HCL (.3 mL). Fifteen minutes later add 2.5 mL more water. Set up vacuum filtration and use that to collect the product using ice water to wash the solid. Let the product dry for fifteen minutes and determine the crude yield and melting point. Save a small portion of crude material for TLC analysis. Recrystallize the crude solid using acetone and an Erlenmeyer flask. Use around 1 to 1.5 mL of the solvent. After the compound is crystalized, let it dry and come back during evening hours to take the melting point and final percent yield. The next process is to do the TLC analysis. Dissolve benzoin, recrystallized product, and crude product in ethyl acetate in three separate vials. Set up two separate TLC plates. On the first put dots of starting material, recrystallized product, and a dot of each. On the second plate put a dot of the starting material, the crude product, and one of both together. Place the 9:1 CH₂Cl₂: ethanol in the TLC developing chambers and add the plates. Let the solution run until its 1cm below the top. Once the plates are finished developing use the UV light and circle the new markings that developed.