Abstract:

The concept of chemical reactions is very complex. During our courses of Organic Chemistry at UNAM (Universidad Nacional Autónoma de México, Facultad de Química), we try to provide key elements to our undergraduate students of the different factors affecting the rate of the reactions.
The use of Microwave in Organic Synthesis has become an important tool for speed reactions.
We have developed a new laboratory experiment involving; Microwave, Oxiranes and Amines in order to teach the influence of the electroactracting and electrodonating groups in the rate of reaction in the amino alcohol's formation.
Using a CEM Explorer Microwave equipment, changing the power, time of reaction and the nature of the aniline, it is possible to explain the influence of the nucleophilic nitrogen in the speed of the reactions. Activated (p-methoxyaniline, p-methylaniline) neutral (aniline), and deactivated (p-nitroaniline, p-cyanoaniline) were used with 1,2-epoxybutane. The identification of the products was done using (Nuclear Magnetic Resonance) NMR spectroscopy. These experiments allow us to monitor the % of conversion, and the products obtained. Students perform the experiment in 2 to three sessions of 3 hrs. each one, and can obtain very interesting conclusions, about the influence of different factors in the speed of the reactions.
Using NMR, students can interpret the influence of the electronic configurations in the speed and selectivity of the reaction. This laboratory experiment helps students to understand in a deeper way the concepts of kinetics and selectivity of reactions.
The Laboratory curricula has been reinforced using a virtual environment to simulate the experiments students are performing. Simulation of the reactions in 3D using semi empirical methods as HF (Hartree Fock) to find the transition state, are performed and the visualization in a 3D environment, in which students can visualize the complete pathway of the reactions and study each of the steps involved.

These work was partially supported by a grant from Dirección General de Asuntos del Personal Académico (DGAPA) Universidad Nacional Autónoma de México (UNAM) IX200810 and SSA/IMSS/ISSSTE-CONACYT 126876

Keywords:

Microwave, Reactions, Organic Reactions, Laboratory.