Answer Happy

Vanillin is the primary extract of the vanilla bean. In this lab you are going to esterify it with acetic anhydride in the presence of acid or base. You will then use NMR to determine the structures of the products. NaOH Result A HO + Stereo C-H сH,0 H2SO4 Result B
PROCEDURE Base conditions 1. Dissolve 0.30 g of vanillin in 5 mL of 10% NaOH in a 50 mL Erlenmeyer flask. 2. Add 6 g of crushed ice and 0.8 mL of acetic anhydride. 3. Stopper with a clean, rubber stopper. Shake intermittently over a 20 minute period. A cloudy, white precipitate will form. Filter the precipitate and wash with ice cold water. 4. Recrystallize the solid in 95% alcohol. Use heat to dissolve the solid. Stay below 60C to avoid melting the solid. 5. When the crystals are dry collect a percent yield, melting point, and 'H NMR Acid conditions 1. In a 3 mL conical flask: Place a magnetic spin vane, 0.15 g vanillin, and 1.0 mL of acetic anhydride. Stir the mixture at room temperature until the solid dissolves. 2. While stirring, add one drop of 1.0 MH,SO, Cap the vial and stir at room temperature for one hour. The solution should turn purple or purple-orange. 3. Transfer to a vial/tube with a well-fitting cap. Cool in an ice water bath for 3-4 minutes. Add 3.5 mL of ice cold water to the vial. Shake vigorously until a solid forms. It should form in 10-15 minutes. Filter the precipitate and wash with ice cold water. 4. Recrystallize the solid in 95% alcohol. Use heat to dissolve the solid. Stay below 60C to avoid melting the solid. 5. When the crystals are dry collect a percent yield, melting point, and 'H NMR.
CHO Босн. OCH, 4-formyl-2-methoxyphenyl acetate Result A [4-(acetyloxy)-3-methoxyphenylmethanediyi diacetate Result