Introduction
                                                                                       Functional group      pK
        •    The acidity of organic compounds is often determined                                               a
             by neighboring groups because they can help stabilizing                   Alkane                 ~50
             the resulting anion (i.e., halogen, nitro, etc.) because of               Ester                  ~25
             their electronegative character or due to resonance                       Aldehyde/ketone     ~18-20
             (i.e., enolate in carbonyl compounds)                                     Alcohol             ~15-19
                                                                                       Nitro                ~8-10
        •    For instance, the presence of a carbonyl group greatly increases the acidity of 
             neighboring hydrogen atoms (a-protons) because of the resonance stabilization in the 
             resulting enolate ion (the numbers in parentheses below are from acetone, AM1) 
             127.8 pm
           (123.5 pm)
                             137.4 pm
                           (149.5 pm)
        •    Many of the carbonyl compounds can be deprotonated with moderately strong bases i.e., 
             hydroxide, alcoholates, etc.
                           Aldol Condensation
       • Ketones and aldehydes can be reacted with each other 
           in Aldol or Claisen-Schmidt condensation:
                           H         H         -       O    OH      T         O
                               +            [OH]                                           Aldol
                         O         O                 H                      H
                       Ph   H          H Self condensation of acetaldehyde  to 
                                                        O    OH                 O
                                          form crotonaldehyde also called "aldol"
                                                -                     T
                                +            [OH]
                          O         O                 H        Ph             H        Ph
                                              Formation of cinnamaldehyde
                     Theory for the Experiment I
        • In Chem 14CL, acetone is reacted with two equivalents 
            of benzaldehyde using sodium hydroxide as catalyst:
                                                                                 O
                                   CHO
                                            O     NaOH(aq.)/EtOH
                        2              +                                                             + 2H2O
        • The first step is the formation of the first enolate ion:
                                      O                       O               O
                                                                                         +  H O
                                      C C    + –                                           2
                                                OH            C C             C C
                                        H
                                                                    enolate ion
        • Note that water is one of the products in the enolate formation 
             the amount of water has to be minimized in order to optimize 
            the amount of enolate in the reaction mixture.
             Theory for the Experiment II
      •   The enolate ion acts as the nucleophile, which attacks the 
          carbonyl group of the benzaldehyde to form the new C-C bond:
      •   The trans, trans-isomer is primarily formed and isolated in the 
          reaction.
      Running the Reaction
  • Acetone is reacted with two equivalents of 
   benzaldehyde in a small Erlenmeyer flask.
  • An aqueous ethanolic solution of sodium 
   hydroxide is added slowly (drop wise) while 
   stirring. 
  • The mixture is stirred for 30 minutes.
  • The crude product precipitates as a yellow 
   solid from the solution during the reaction.