Ketone Reduction Using Sodium Borohydride

Experiment 5B: Ketone Reduction Objective: Using sodium borohydride as a reducing agent, the ketone 4-tert-butylcyclohexane is reduced to its corresponding alcohol. It is purified through extraction techniques to give the cis and trans diasteromer products. Procedure: The procedure was followed as outlined in Mayo’s book for Experiment 5B with the following modifications: 1. Reagents and Equipment – The reaction will be on a scale of 2X what is described in the text. 2. Reagents and Equipment – The progress of the reaction will be followed by TLC as directed in the Reaction Conditions section.Glass backed TLC plates will be created with the following three spots: Ketone Standard/Co-Spot/Crude Reaction Mixture. Prepare the TLC plate while the reaction is being set up. To the initial solution of 4-tert-butylcyclohexane in methanol, before adding the reducing solution, insert a TLC capillary. Use this sample as your ketone standard. Do NOT stop the reaction before c hecking the progress by TLC. If the reaction is not complete, add another portion of the reducing solution. 3. Isolation of Product – All other amounts specified in this section should be followed without doubling. . Isolation of Product – Substitute 1. 0 mL of cold 3. 0 M HCl for 1. 0 mL of cold 0. 1 M HCl. 5. Purification and Characterization – Will not obtain an NMR spectrum. Reaction Scheme: Data and Results: CompoundMW (g/mol)AmountMmolMp (degrees C)Bp (degrees C) 4-tert-butylcylcohexane154. 25103 mg0. 6747 – 50 Methanol32. 04100  µL65 Sodium Borohydride reducing solution37. 83200  µL *NOTE: As I was condensing my product in the sand bath it â€Å"popped† and there was no more final product in my vial. Therefore I was not able to do a final analysis and I am using Mike Mariani’s data in my report.Observations: 1. Crude product was solid and white in color. 2. TLC spots were dark purple for both the ketone standard and co-spot. The s pot for the crude reaction mixture was barely visible. 3. Melting point of product started at 62. 5 degrees Celsius. Calculations: 1. TLC was done in an elution solvent system of ethyl acetate: hexane (1:4). QQ did not have us record Rf values. The color of the spots was as indicated in the observations section above. 2. Yield of Crude Product = Vial and product – Vial: 4. 233 g – 4. 141 = 0. 092 g = 92 mg 3. Percent Yield of Crude Product: