Chapter 21, Problem 2E

Why is excess ammonia used in the preceding reaction?

Can you predict an undesirable side reaction that might occur using ethanol as a solvent that would not occur if we used THF as a solvent?

Procedure To a 100-mL Erlenmeyer flask equipped with a stir bar add furfural (3 mL) and acetone (1 mL). Add ethanol (5 mL) and stir the mixture. Carefully add 10% sodium hydroxide solution (2 mL) and continually stir the mixture for 1h, note any changes. Place a 500 mL beaker containing water-ice (300 mL) in an ice bath. Remove the stirring bar from the aldol reaction using a magnetic retriever or a spatual and place the bar in the beaker. Stir the solution vigorously. Using a glass pipette, add dropwise the reaction mixture. This must be done very slowly and with vigorous stirring to prevent oiling out of the product. If the product oils out, you will not be able to filter it after stirring vigorously for an additional hour! You may also need to use a stirring rod. After the addition, make sure that there is no oil in the bottom of the beaker. If there is, continue stirring. Filtering oils will clog the filter paper. Vacuum filter the solids using a large Buchner funnel. Wash the…