ERIC Number: EJ1040074
Record Type: Journal
Publication Date: 2014-Sep
Abstractor: As Provided
Reference Count: 14
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.
Descriptors: Science Experiments, Laboratory Experiments, Scientific Principles, Molecular Structure, Chemistry, College Science, Undergraduate Study, Scientific Concepts, Spectroscopy, Science Instruction
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: firstname.lastname@example.org; Web site: http://pubs.acs.org/jchemeduc
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Authoring Institution: N/A