TA Luke Harris
Submitted: 11/13/07 Objective: The objective of this experiment was to synthesize cis-norbornene-5,6-end-
dicarboxylic anhydride from maleic anhydride and cyclopentadiene. This reaction occurs
because of the Diels-Alder mechanism in which carbon-carbon bonds are made and a six-
membered ring forms.
Reaction Equations: The mechanism for this experiment is the Diels-Alder reaction.
This occurs when there is a conjugated -diene that can rotate to the cis form, and an -ene.
In the Diels-Alder reaction, the –ene is called the dienophile because it want a –diene. It
is a six-pi-electron reaction that results in the combination of the two products into a six-
membered ring. The reaction is concerted, meaning that all steps occur at once. Two
products result in this reaction: the endo product and the exo product. The endo product
is the major product, and the exo product is the minor product. The arrow-pushing
mechanism can be found on the attached page.
Procedure: This experiment began with the addition of approximately 0.2 grams of
powdered maleic anhydride, 1.0 milliliter of ethyl acetate, and 1.0 milliliter of ligroin
(hexane) to a test tube. To this test tube, 0.2 milliliters of dry cyclopentadiene were
added. The tube was then cooled by running faucet water over the test tube to crystallize
the resulting product.
The crystals were separated from their solvent by vacuum filtration with a Hirsch
funnel. Once the crystals were dry enough, their mass was observed, and the melting
point range determined. Calculations: The first calculation is of the theoretical yield.
Moles of Maleic Anhydride: 0.2 g × 98 g = 2.04 ×10 mol
0.8 g 1mol −3
Moles of Cyclopentadiene: 0.2mL × 1mL × 66 g = 2.42 × 10 mol
The limiting reactant is maleic acid. The products and reactants are in