Locker Number: ________________
Chemistry 355: Photoreduction of Benzophenone and
Synthesis of Benzopinacolone
Experiment 49A: Photoreduction of Benzophenone
1. Report the grams of benzpinacol that you obtained in this experiment.
- Calculate the grams of product expected. Also calculate the percentage yield using the weight you obtained in part 1. Be sure to show your calculation setup.
Experiment 49B: Synthesis of benzopinacolone: the acid-catalyzed rearrangement of benzpinacol
- Report the grams of benzopinacolone that you obtained in this experiment.
- Calculate the grams of product expected. Also calculate the percentage yield using the weight that you obtained in part 3. Be sure to show your calculation setup.
- Report the melting point range of your product.
- Attach the infrared spectrum of your product, if required by your instructor. Be sure to label the significant absorption bands.
- Submit the product with this laboratory report. Use a properly labeled vial.
Answer the following questions:
1. Circle the molecules that you would expect to quench the benzopheone photoreduction reaction.
trans-1,3-pentadiene (T1 = 59 kcal/mol) Naphthalene (T1 = 61kcal/mol)
Biphenyl (T1 = 66 kcal/mol) Toluene (T1 = 83 kcal/mol)
Benzene (T1 = 84 kcal/mol)
- Draw a mechanism for the rearrangement of benzpinacol to benzopinacolone, ignoring the possible role of iodine in the mechanism. Do an acid-catalyzed mechanism.