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Synthesis of Methyl Benzoate

 

Post –Laboratory Questions

 

 

1.      What are esters?  What is their general structure?

Esters are alkyl molecules linked by oxygen atoms. 

 

2.      What is the role of the mineral acids in the esterification process?

To activate the oxygen atom which at the moment is part of the carboxylic acid.  It is activated by removing the hydrogen with the conjugate base of the mineral acid.  The conjugate base forms through the dehydration of the alcohol.   

 

3.      Give the structure of the product formed in the following esterification reaction.

 

 

 

 

4.      What alcohol and carboxylic acid are required for the synthesis of the following esters?

 

 

(a)

                                  

 

 

(b)

                          

 

 

METHYL BENZOATE REPORT SHEET

 

 

NAME          Albert Lu                                              LOCKER NUMBER     59       

 

DATE           12 November 2004                  LAB DAY AND TIME  Fri 1105           

 

 

PRELIMINARY CALCULATIONS

 

A.     WEIGHT of BENZOIC ACID from Cannizzaro Rxn                      4.27       g

 

B.     WEIGHT of BENZOIC ACID from Benzonitrile Rxn                     0.98       g

 

C.     Combined weight of BENZOIC ACID                   5.25       g

 

D.     VOLUME of METHANOL  2.5 x (C)                   13.125   mL

 

E.      VOLUME of CONC. SULFURIC ACID  0.3 x (C)          1.575                 mL

 

F.      VOLUME of DIETHYL ETHER  4.0 x (C)                       21          mL

 

 

CALCULATION OF THEORETICAL YIELD

 

1.      Molecular Weight of Benzoic Acid                          122.123             g/mol

 

2.      Moles of Benzoic Acid used                       0.043     moles

 

3.      Molecular Weight of Methyl Benzoate                     136.15   g/mol

 

4.      Theoretical Yield of Methyl Benzoate                      5.853     g

 

 

RESULTS

 

1.      BOILING POINT of Methyl Benzoate                   199.6     °C

 

2.      Actual Yield of Methyl Benzoate                 2.98       g

 

3.      Percent Yield                      50.9       %