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2005
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In the Laboratory
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Chiral Crystallization of Ethylenediamine Sulfate
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Lawrence Koby, Jyothi B. Ningappa, Maria Dakessian, and Louis A. Cuccia
Department of Chemistry & Biochemistry, Concordia Universiry, 7141 Sherbrooke Street West, MontrŽal, QuŽbec H4B 1R6, CANADA
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July 2005
Vol. 82 No. 7
p. 1043
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| Abstract |
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Optimized conditions for the chiral crystallization of ethylenediamine sulfate, which can serve as an ideal undergraduate experiment, are described. Large, flat, colorless crystals of ethylenediamine sulfate are obtained in an undisturbed evaporation dish within a period of approximately five to seven days. The crystals are ideal for polarimetry studies and observation using Polaroid sheets. Students become familiar with polarizing filters and how they can be used to distinguish between dextrorotatory and levorotatory crystals. Of 100 randomly sampled crystals, 47 crystals showed a (+)-rotation, while 53 crystals showed a (-)-rotation. The absolute value of the average optical rotation of the 100 crystals was found to be 158/mm ± 2 for the D line of sodium. The relative direction of rotation of polarized light was also determined by simply observing the change in optical rotatory dispersion of the crystals placed between two Polaroid sheets as one of the sheets was rotated clockwise or counter clockwise.
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| Supplement |
Instructions for the students and notes for the instructor are available.
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 Contents |
JCE2005p1043W.doc (Microsoft Word)
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| More Information |
Citation |
Koby, Lawrence; Ningappa, Jyothi B.; Dakessian, Maria; Cuccia, Louis A. J. Chem. Educ. 2005 82 1043.
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Keywords |
Chirality / Optical Activity; Crystals / Crystallography; Hands-On Learning / Manipulatives; Laboratory Instruction; Organic Chemistry; Physical Chemistry; Physical Properties; Second-Year Undergraduate; Stereochemistry; Upper-Division Undergraduate
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History |
Created:
Last Updated: |
May 31, 2005
June 8, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
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