Each step in this process is reversible meaning that some of the carboxylic acid and alcohol compounds remain in equilibrium. To keep from the formation of too much carboxylic acid or alcohol, one must add excess reactant or remove some ester product, to push the reaction to produce more ester. .
This experiment is the synthesis of a 7-oxanorbornene derivative using Diels-Alder reactions. This particular experiment is a two-step sequence beginning with the Diels-Alder, and then ending with a ring opening by Fischer esterification. .
Chemical Reactions:.
Part One:.
Part Two:.
Calculations:.
Part One:.
Theoretical Yield - 166.133 g/mol x 0.045 mols = 7.476g.
Percent Yield - (5.096 / 7.476) x 100 = 68.28%.
Part Two:.
Theoretical Yield - 212.17 g/mol x 0.030 mols = 6.363g.
Percent Yield - (6.03 / 6.363) x 100 = 94.7%.
Data:.
Part One Experimental Yields.
Molecular Weight 1st Theoretical Yield (g) 1st Experimental Yield (g) 1st Percent Yield 1st M.P. ( C) Lit M.P. ( C).
166.133 7.476 5.096 68.28 114-118 116-117.
Part Two Experimental Yields.
Molecular Weight 2nd Theoretical Yield (g) 2nd Experimental Yield (g) 2nd Percent Yield 2nd M.P. ( C) Lit M.P ( C).
212.17 6.363 6.03 94.3 114-118 115.5-118.
IR spectrum from Experimental Yields.
Functional Group Frequency (cm-1).
C-H 2900.
C=O 1700.
Diagram: .
IR spectrum.
.
Please refer to last page for sketches of equipment and apparatuses used in this lab.
Discussion:.
This experiment was a two-step process beginning with a Diels-Alder Reaction, then a reflux that allowed for a ring opening. The Diels-Alder reaction occurred between furan and maleic acid, forming an anhydride. In this part of the reaction, the Diels-Alder is odd in the fact that it produces an Exo- product. Most Diels-Alder reactions produce an Endo- product since it is the most kinetically favored of the two. Why the product formed is exo- and not endo- is not fully understood. The exo- product is formed most likely due to the problem of sterics and the exo- product is the least sterically hindered.