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2003
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November
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In the Laboratory
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The Microscale Laboratory
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A Series of Small-Scale, Discovery-Based Organic Laboratory Experiments Illustrating the Concepts of Addition, Substitution, and Rearrangement
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Judith S. Moroz, Janice L. Pellino, and Kurt W. Field
Department of Chemistry and Biochemistry, Bradley University, Peoria, IL 61625
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November 2003
Vol. 80 No. 11
p. 1319
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| Abstract |
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Multistep, microscale organic laboratory experiments are presented that illustrate addition, substitution, and rearrangement reactions. The sequence begins with the preparation of 1,2-dichloro-1,1,2,2-tetraphenylethane, 2, from tetraphenylethene, 1, and acidified bleach. Although numerous reagents, including chlorine gas, have been used to prepare vic-dichlorides, we discovered that acidified household bleach can serve as an inexpensive and effective green chlorinating agent affording a high purity product in essentially quantitative yield. The reaction of 2 with silver ion and water is both solvent and water concentration dependent. In aqueous acetone (~11% water), 2 affords near quantitative yields of tetraphenylethene oxide, 3. However, in aqueous methanol (~1% water), 2 gives 2,2,2-triphenylacetophenone, 4, almost exclusively. Finally, 3 can be isomerized to 4 in the presence of boron trifluoride. As part of the laboratory exercises, the students are asked to suggest mechanisms consistent with the reaction stoichiometry, their observations, and the elucidated structures of the products. The experiments are safe, reliable, and inexpensive. They utilize basic laboratory glassware, are operationally uncomplicated, and can each be performed in a 3-hour laboratory period. The scale of the reactions and the fact that reaction products can serve as substrates for the next transformation minimizes waste and disposal issues.
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| Supplement |
Detailed procedures for this laboratory, notes for the instructor, and sample spectra are available.
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| More Information |
Citation |
Moroz, Judith S.; Pellino, Janice L.; Field, Kurt W. J. Chem. Educ. 2003 80 1319.
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Keywords |
Inquiry-Based / Discovery Method; IR Spectroscopy; Laboratory Instruction; Mass Spectrometry; Microscale; NMR Spectrometry; Organic Synthesis
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History |
Created:
Last Updated: |
October 2, 2003
February 28, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
2003
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November
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1319
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