Diels alder reaction lab question

Question

I recently did a lab in my organic chemistry class where we reacted cyclopentadiene and maleic anhydride to produce cis-norbornene-5,6-endo-dicarboxylic anhydride. My question is, why was the maleic anhydride first dissolved in ethyl acetate and hexane before adding the cyclopentadiene? Why couldn't the maleic anhydride just be thrown into the liquid cyclopentadiene?

Answer 1

Diels-alder reactions are spontaneous at room temperature with a negative enthalpy value. This means that the reaction is extremely exothermic proportional to the relative concentrations of the reagents. A solvent is typically used to achieve the desired concentrations of reagents. Nucleophilicity also heavily depends on the solvent used, so for many reactions involving nucleophilic attack, a solvent is necessary.