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  Home > JCE Print > Journal of Chemical Education > Issues > 2008  > September  >
In the Laboratory
The Comparative Nucleophilicity of Naphthoxide Derivatives in Reactions with a Fast-Red TR Dye
A Discovery-Oriented Capstone Project for the Second-Year Organic Laboratory
Cheryl M. Mascarenhas
Department of Chemistry, Benedictine University, Lisle, IL 60532
Cover
September 2008
Vol. 85 No. 9
p. 1271

Abstract
In this experiment, organic chemistry students perform reactions between three naphthyl acetate derivatives and the diazonium salt Fast-Red TR, under basic conditions. The three naphthyl acetate derivatives used in this study are 2-naphthyl acetate (1a), 6-bromo-2-naphthyl acetate (1b) and 1,6-dibromo-2-naphthyl acetate (1c). The two-step, one-pot reactions (ester hydrolysis followed by reaction with Fast Red TR) are screened for the formation of an orange–red diazo dye both visually and by UV–vis spectroscopy. Students discover that the hydrolysis and electrophilic aromatic substitution is the fastest with ester 1a and the slowest with ester 1c. This allows students to conclude that electrophilic aromatic substitution, rather than ester hydrolysis, is rate-limiting. This experiment is performed over a two-week period: during the first week students synthesize and purify compounds 1b and 1c, which are easily characterized through 1H NMR and IR spectroscopies. The ester hydrolysis and diazotization visual and UV–vis studies are performed during the second week of the experiment.
Supplement
Detailed experimental procedures for the students; Notes for instructors; NMR, IR, and UV–vis spectra and TLC data; Assessment information
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Citation
Mascarenhas, Cheryl M. J. Chem. Educ. 2008, 85, 1271.
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Keywords
Alcohols; Aromatic Compounds; Dyes / Pigments; Esters; Hands-On Learning / Manipulatives; Inquiry-Based / Discovery Learning; IR Spectroscopy; Laboratory Instruction; NMR Spectroscopy; Organic Chemistry; Second-Year Undergraduate; Synthesis; Thin Layer Chromatography; UV-Vis Spectroscopy
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History
Created:
Last Updated:
8/4/2008
8/4/2008
 Caution! 
Experiments, laboratory exercises, lecture demonstrations, and other descriptions of the use of chemicals, apparatus, instruments, computers, and computer interfaces are presented in the Journal of Chemical Education as illustrative of new or improved ideas or concepts in chemistry instruction and are directed at qualified teachers. Although every effort is made to assure and encourage safe practices and safe use of chemicals, the Journal of Chemical Education cannot assume responsibility for uses made of its published materials. Many chemicals are hazardous. Precautions for the safe use of hazardous chemicals and directions for their proper disposal are described in the Material Safety Data Sheets and on the labels. We strongly urge all those planning to use materials from our pages to make choices and to develop procedures for laboratory and classroom safety in accordance with local needs and situations.
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