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ERIC Number: EJ1040074
Record Type: Journal
Publication Date: 2014-Sep
Pages: 5
Abstractor: As Provided
Reference Count: 14
ISBN: N/A
ISSN: ISSN-0021-9584
Noncovalent Derivatization: A Laboratory Experiment for Understanding the Principles of Molecular Recognition and Self-Assembly through Phase Behavior
Cannon, Amy S.; Warner, John C.; Koraym, Smaa A.; Marteel-Parrish, Anne E.
Journal of Chemical Education, v91 n9 p1486-1490 Sep 2014
An experiment focusing on the creation of phase diagrams involving nonconvalent derivatives of hydroquinone and bis[N,N-diethyl]terephthalamide (HQ-DETPA) is presented. A phase diagram was assembled by taking samples of different compositions (i.e., 40% hydroquinone and 60% bis[N,N-diethyl]terephthalamide, 70%/30%, etc.) and determining the melting points of each sample. This experiment is suitable for students enrolled in a physical chemistry class or materials science course and was effectively accomplished by three pairs of students. The experiment requires two 3-h lab sessions. Background information, experimental procedure and hazards, and results of the research are detailed. Results indicate that the noncovalent derivatization successfully provides a co-crystal that assembles into a 50:50 molar ratio. The eutectic points are shown to take place at the 25:75 and 75:25 molar ratios, respectively. Because entropy was the driving force behind the assembly of the co-crystals, the presence of a maximum point on the phase diagram, which represents the highest value of enthalpy and lowest point of entropy, was also witnessed and occurred at the 50:50 molar ratio of HQ to DETPA.
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A