Resumen de Preparing 4-Ethoxyphenylurea Using Microwave Irradiation: Introducing Students to the Importance of Artificial Sweeteners and Microwave-Assisted Organic Synthesis (MAOS)
Spence C. Pilcher, Joshua Coats
In today’s world of instant coffee, instant meals, and instant messaging, undergraduate students prefer not to have to wait 30–60 min for an organic reaction to take place. Heating with microwaves is rapidly becoming more commonplace due to dramatically reduced reaction times and higher product yields. Students appreciate the short reaction times and like working with advanced technology by means of the commercial microwave reactors available today. Furthermore, undergraduate organic students like being able to relate an experiment to something that they see every day. For these reasons, the synthesis of pharmaceuticals, extracting caffeine from tea, and isolating trans-cinnamaldehyde from cinnamon sticks are popular experiments. One such experiment is the synthesis of the artificial sweetener dulcin (4-ethoxyphenylurea), which can be prepared from the reaction of p-phenetidine and urea. Artificial sweetening agents are extremely important to the food industry because of the national concern with diet and weight control. The synthesis of this particular sweetener typically takes at least 30 min to reach completion. However, using microwave irradiation, the reaction reached completion in 5 min using a temperature of 125 °C. This procedure was implemented into the second semester undergraduate organic chemistry laboratory curriculum where students successfully prepared dulcin with reported yields ranging from 10% to 86% and an average yield of 39% after recrystallization.
