Carboxylic Acid Reactions

							                                             Carboxylic Acid Reactions
Preparation of Carboxylic Acids

1) Oxidation of 1o alcohols with a strong oxidizer (see Alcohol reactions sheet)

2) Oxidation of alkyl side chains on benzene rings (see Benzene reactions sheet)

3) Grignard plus CO2
                                       CO2
                                                                              OH
                       MgX                    +
                                       2) H
                                                                          O
2) Hydrolysis of a nitrile

                                       H2 O                           OH
                           N
                                   H+ or OH-
                                                                      O



        ** To form a nitrile, react a 1o alkyl halide with the CN− ion **

                                   CN-
                       X
                                                                     N

Preparation of acyl halides (acid chorides and acid bromides)

1) React a carboxylic acid with SOCl2, PBr3, or PCl3
                                                                  O
                O
                                   SOCl2
                                                                         Cl
                     OH


                O                                                O
                                   PX3

                     OH                                               X


Preparation of acid anhydrides

1) React an acyl halide with a carboxylic acid
               O                    O                                              O       O

                     OH        +                                                       O       R
                                   R         X

2) Dehydration (heating) of a carboxylic acid
              O                     O                                              O       O
                                                        heat
                     OH        +                                                       O       R
                                   R         OH
Preparation of Esters

1) Equilibrium reaction of a carboxylic acid and an alcohol (less desirable)

                  O                              OH                        O        R

                          OH    +                                               O         R
                                            R         R'

2) Reaction of an alcohol with an acid anhydride or acyl halide (desirable)

                                                      O                                   O

                          OH            +
                                                 R         X                        R         O

                                            O                                   O
        R'OH              +
                                    R           X                         R         OR'

Preparation of Amides
                                                                       (i.e amine)
1) Less desirable -- Heating a carboxylic acid with NH3/amine (the N group must have at least one H on it)

                  O                                                        O
                                                               heat
                          OH    +           HNR2                                NR2

2) More desirable -- Reaction of NH3/amine with an acid anhydride or acyl halide (the amine must have an H)

              O                                                                 O
                               +                HNR2
        R'            X                                                   R'        NR2



              O            O                                                        O
                                            +        HNR2
        R'            O        R'                                              R'       NR2



Reactions of Carboxylic Acids

1) Salt formation – reaction of a carboxylic acid with an alkali metal hydroxide (NaOH, LiOH, KOH)

                  O                                                   O
                                                MOH
                          OH                                              O M
Reactions of Esters

1) Hydrolysis

                     O
                                           H2 O                   O
                             R'
                 R       O                                                         +      R'OH
                                              H+          R               OH

2) Transesterification

                     O                                        O
                                       R"OH
                             R'                                            R"      +     R'OH
                 R       O                 +          R               O
                                          H

3) Ammonoylsis

                     O                                        O
                                          NH3
                             R'
                 R       O                            R               NH 2         +     R'OH
                                          heat

4) Saponification

                     O                                        O
                                       NaOH
                             R'                                                    +     R'OH
                 R       O           H2 O, heat       R               O Na+

5) Reduction – produces a primary alcohol

                     O
                                     LiAlH4 , ether
                             R'                               OH
                 R       O                     +      R                        +       R'OH
                                       2) H
                                                      1o alcohol


6) Grignard reaction – produces a tertiary alcohol

                     O                                        R"
                                      2       R"MgX                       OH
                             R'
                 R       O          ether 2) H
                                              +           R               R"
Reactions of Amides

1) Hydrolysis

                     O
                                    H2 O , heat                 O

                 R       NH 2                                                 +    NH3
                                          H+            R               OH


2) Alcoholysis

                     O                                      O
                                  R"OH , heat
                                                                         R"   +   NH3
                 R       NH 2           +           R               O
                                      H

3) Reduction – use LiAlH 4 to produce an amine

                     O
                                   LiAlH4 , ether

                 R       NH 2            +          R               NH 2
                                     2) H