Aldol Condensation Reaction Rate Demonstrates Steric and Electronic Substituent Effects in the Organic Chemistry Lab

摘要

Aldol chemistry is highlighted in many introductory organic chemistry laboratory experiments because it provides synthesis, mechanism, and experimental challenges for students. In the experiment described here, students synthesize dibenzalacetone derivatives by crossed aldol condensation, observe reaction rates using a semiquantitative rubric, and illustrate the connection between reactant structures and reaction rate through their knowledge of the reaction mechanism. By combining class data and working through a guided-inquiry questionnaire, students link reaction rates with nucleophile and electrophile characteristics of the reactant structures. Independent rate determination of the aldol addition step, using UV absorption, confirmed that student rate observations of the overall reaction are a valid approach to learning about structure?function effects.