Name: ________________________

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.

  1. 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

 

  1. Report the grams of benzopinacolone that you obtained in this experiment.
  2.  

  3. 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.
  4.  

     

     

     

  5. Report the melting point range of your product.
  6.  

  7. Attach the infrared spectrum of your product, if required by your instructor. Be sure to label the significant absorption bands.
  8.  

  9. 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)

  1. Draw a mechanism for the rearrangement of benzpinacol to benzopinacolone, ignoring the possible role of iodine in the mechanism. Do an acid-catalyzed mechanism.