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The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume 15 (2010) pp 146-149

An Integrated Laboratory Experiment That Demonstrates Equilibrium Principles and the Preparation of b-Glucose

Dan DiLella*, Eugene J. Volker, Jing H. Dong and Brandi Helmick

Department of Chemistry, Shepherd University, Shepherdstown WV 25443, ddilella@shepherd.edu
Received January 20, 2008. Accepted December 26, 2009.

Published: 3 March 2010

Abstract. This paper describes an experiment that is designed for an integrated laboratory course but is also suitable for an organic laboratory course. The purpose of the experiment is to illustrate equilibrium principles through an NMR study of aqueous solutions of a-glucose and b-glucose. The students prepare b-glucose from a-glucose and then analyze the product by IR spectroscopy. Aqueous solutions containing either a-glucose or b-glucose are monitored by NMR spectroscopy to illustrate the glucose mutarotation reaction discussed in textbooks. The experiments demonstrate that the same equilibrium mixture is obtained from a solution that originally contained only one of the sugars. The effect of base catalysis on the equilibrium is also demonstrated.

Key Words: Laboratories and Demonstrations; organic chemistry; NMR

(*) Corresponding author. (E-mail: ddilella@shepherd.edu)

Article in PDF format (147 KB) HTML format

Supporting Materials:

A student handout and instructor's notes are available as supplementary materials. The student handout includes detailed instructions for the experiment as well as some theoretical background for the mutarotation reaction. A procedure for following the mutarotation by polarimetry is also provided for those who are interested in comparing it to the NMR method (22 KB).




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