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1. Evildoer or Do-Gooder: Getting the Goods on Ozone (EJ813397)
Author(s):
Fisher, Diane K.
Source:
Technology Teacher, v68 n1 p25-29 Sep 2008
Pub Date:
2008-09-00
Pub Type(s):
Journal Articles; Reports - Descriptive
Peer-Reviewed:
Yes
Descriptors: Climate; Chemistry; Pollution; Spectroscopy; Class Activities
Abstract: This article describes the differences of good ozone and bad ozone. Good ozone, which is found in the stratosphere, protects people and other living things from the bad things UV can do, such skin cancer, cataracts, and other problems. However, lower in the atmosphere, at the top of the troposphere (around 12 miles up), ozone acts like a greenhouse gas, trapping heat from Earth and preventing it from escaping into space. Scientists use an instrument called spectrometer to understand the complicated ozone chemistry. This article describes how a spectrometer can be made in the classroom. (Contains 1 footnote.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
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2. Synthesis and Base Hydrolysis of a Cobalt(III) Complex Coordinated by a Thioether Ligand (EJ814866)
Roecker, Lee
Journal of Chemical Education, v85 n11 p1562-1564 Nov 2008
2008-11-00
Descriptors: Kinetics; Inorganic Chemistry; Laboratory Experiments; Science Laboratories; Science Experiments; Science Instruction; Spectroscopy; College Science
Abstract: A two-week laboratory experiment for students in advanced inorganic chemistry is described. Students prepare and characterize a cobalt(III) complex coordinated by a thioether ligand during the first week of the experiment and then study the kinetics of Co-S bond cleavage in basic solution during the second week. The synthetic portion of the laboratory is a good introduction to the preparation of inert transition-metal complexes and the modification of coordinated ligands. The kinetic portion of the laboratory introduces students to the S[subscript N]1CB base hydrolysis mechanism and to the analysis of kinetic data. (Contains 4 figures.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
3. A More Challenging Interpretative Nitration Experiment Employing Substituted Benzoic Acids and Acetanilides (EJ814860)
Treadwell, Edward M.; Lin, Tung-Yin
Journal of Chemical Education, v85 n11 p1541-1543 Nov 2008
Journal Articles; Reports - Evaluative
Descriptors: Spectroscopy; Organic Chemistry; Science Experiments; Laboratory Experiments; Molecular Structure; College Science; Science Instruction; Scientific Concepts
Abstract: An experiment is described involving the nitration of ortho or meta monosubstituted benzoic acids (XC[subscript 6]H[subscript 4]CO[subscript 2]H, X = Halogen, Me, OH, or OMe) and monochlorinated acetanilides with nitric acid to determine the regioselectivity of addition by [superscript 1]H NMR spectroscopy and molecular modeling. Students were able to interpret the [superscript 1]H NMR spectra regardless of the formation of multiple products or contamination from the starting materials. With one exception, both the [superscript 1]H NMR spectroscopy and computational methods agreed with the theoretical expectation and provided a nice demonstration of regioselectivity of nitration on substituted benzene. (Contains 2 tables, 1 figure and 1 note.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
4. The Synthesis of "N"-Benzyl-2-Azanorbornene via Aqueous Hetero Diels-Alder Reaction: An Undergraduate Project in Organic Synthesis and Structural Analysis (EJ814859)
Sauvage, Xavier; Delaude, Lionel
Journal of Chemical Education, v85 n11 p1538-1540 Nov 2008
Descriptors: Organic Chemistry; Science Laboratories; Laboratory Experiments; Science Instruction; College Science; Spectroscopy; Molecular Structure; Computation; Science Process Skills
Abstract: The synthesis of "N"-benzyl-2-azanorbornene via aqueous hetero Diels-Alder reaction of cyclopentadiene and benzyliminium chloride formed in situ from benzylamine hydrochloride and formaldehyde is described. Characterization of the product was achieved by IR and NMR spectroscopies. The spectral data acquired are thoroughly discussed. Numerous coupling constants were extracted from the [superscript 1]H NMR spectrum. They provide a valuable material to familiarize students with the different types of proton-proton coupling patterns and their typical ranges. Karplus type correlations served to calculate [superscript 3] "J" vicinal coupling constants as a function of dihedral angles. These computational studies involved molecular modeling. Because the synthetic part is rather straightforward and easy to carry out, this experiment is suitable for an introductory laboratory course where it can serve to illustrate the concepts of green chemistry and atom efficiency. Emphasis can also be placed on structural analysis for use within a spectroscopy course even if there is no activity component associated with it. Last but not least, the whole project provides ample materials for an advanced undergraduate laboratory in green chemistry that combines organic synthesis, structural analysis, and theoretical calculations. (Contains 1 figure and 1 table.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
5. The Synthesis of a Cockroach Pheromone: An Experiment for the Second-Year Organic Chemistry Laboratory (EJ814862)
Feist, Patty L.
Journal of Chemical Education, v85 n11 p1548-1549 Nov 2008
Descriptors: Spectroscopy; Organic Chemistry; Science Experiments; Science Laboratories; College Science; Entomology; Science Instruction; Science Process Skills
Abstract: This experiment describes the synthesis of gentisyl quinone isovalerate, or blattellaquinone, a sex pheromone of the German cockroach that was isolated and identified in 2005. The synthesis is appropriate for the second semester of a second-year organic chemistry laboratory course. It can be completed in two, three-hour laboratory periods and uses equipment readily available in most organic chemistry laboratories. In the first step, 2,5-dimethoxybenzyl alcohol reacts with isovaleryl chloride to produce 2,5-dimethoxybenzyl 3-methylbutanoate. In the second step, the 2,5-dimethoxybenzyl 3-methylbutanoate is oxidized using ceric ammonium nitrate to form gentisyl quinone isovalerate. The experiment is interesting to students because it involves the synthesis of a compound that has real-world applications. The experiment affords them practice in the important techniques of extraction, IR spectroscopy, and NMR spectroscopy. (Contains 1 figure.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
6. NMR and IR Spectroscopy for the Structural Characterization of Edible Fats and Oils: An Instrumental Analysis Laboratory (EJ814863)
Crowther, Molly W.
Journal of Chemical Education, v85 n11 p1550-1554 Nov 2008
Descriptors: Spectroscopy; Science Process Skills; Science Instruction; Organic Chemistry; Science Laboratories; Science Experiments; Undergraduate Study; College Science; Molecular Structure
Abstract: This article describes an upper-level instrumental laboratory for undergraduates that explores the complementary nature of IR and NMR spectroscopy for analysis of several edible fats and oils that are structurally similar but differ in physical properties and health implications. Five different fats and oils are analyzed for average chain length, degree of unsaturation, and trans fat content. Careful interpretation of peak areas in 1H NMR spectra provides the extent of unsaturation and the average chain length. IR spectroscopy can easily identify the presence of trans fat. Instruction on acquisition, processing, and interpretation of spectra goes beyond what is typically taught in an organic undergraduate laboratory. This includes specifics on acquisition and digital filtering, examples of complex coupling, and introduction to 2D NMR experiments. After analysis, students must correlate each oil or fat to a given fatty acid distribution. Students can then reconcile the structural composition to the physical properties and health implications. Students work independently, are guided by literature, and get good results on a challenging problem. (Contains 5 tables and 6 figures.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
7. Mass Spectrometry Theatre: A Model for Big-Screen Instrumental Analysis (EJ814871)
Allison, John
Journal of Chemical Education, v85 n11 p1582-1583 Nov 2008
Descriptors: Chemistry; Spectroscopy; Measurement Techniques; Science Instruction; Science Laboratories; Educational Technology; Computer Uses in Education; Teaching Methods; College Science
Abstract: Teaching lecture or lab courses in instrumental analysis can be a source of frustration since one can only crowd a small number of students around a single instrument, typically leading to round-robin approaches. Round-robin labs can spread students into multiple labs and limit instructor-student interactions. We discuss "Mass Spectrometry Theatre" as an example of how to teach instrumental analysis with a single instrument, using a digital projector. Since most instruments are now computer controlled and have few if any dials or indicators, most of the interactions are with the computer. With the computer display projected onto a large screen in the lab, students can interact with the instructor and the data system together, with a small number of operators assigned to use the mouse and keyboard. In this way, the use of any instrument with an attached computer can be taught to larger groups, in the lab, in ways that involve all of the students and the instructor, throughout the laboratory period. Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
8. Identification of Secondary Metabolites in Citrus Fruit Using Gas Chromatography and Mass Spectroscopy (EJ814864)
Lavoie, Jean-Michel; Chornet, Esteban; Pelletier, Andre
Journal of Chemical Education, v85 n11 p1555-1557 Nov 2008
Descriptors: Undergraduate Students; Organic Chemistry; Biochemistry; Spectroscopy; Science Experiments; College Science; Science Instruction; Laboratory Experiments; Molecular Biology; Molecular Structure; Science Process Skills
Abstract: This experiment targets undergraduate students in an analytical or organic instructional context. Using a simple extraction, this protocol allows students to quantify and qualify monoterpenes in essential oils from citrus fruit peels. The procedures involve cooling down the peels by immersing them into icy water. After a few minutes, the chilled peels are pulped in a simple kitchen blender using acidic brine to hydrolyze the undesired fatty acids. Essential oils are extracted from the emulsion using methylene chloride and are then injected in a gas chromatograph coupled with a mass spectrometer. Among the fruit tested--limes, grapefruits, and oranges--all showed a high concentration of ("R")-limonene, a monoterpenoid commonly found in these fruits. Students are invited to quantify ("R")-limonene in the extracts following an accurate 5-point standard calibration curve. For students, this experiment may be a first contact with the analysis of plant extracts as well as an introduction to the biochemistry of monoterpenes. (Contains 2 figures, 2 tables and 1 note.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
9. Synthesis of the Commercial Antidepressant Moclobemide (EJ823759)
More, Jesse D.
Journal of Chemical Education, v85 n10 p1424-1425 Oct 2008
2008-10-00
Descriptors: Organic Chemistry; Drug Therapy; Undergraduate Study; Science Laboratories; Science Instruction; College Science; Spectroscopy; Thermodynamics; Science Experiments
Abstract: An experiment for the undergraduate organic chemistry laboratory is described in which students synthesize the commercial antidepressant drug moclobemide, marketed under the trade name Manerix. This one-step synthesis starts from commercially available material and produces moclobemide in high yield. The product is initially isolated as its hydrochloride salt via precipitation. After recrystallization and treatment with base moclobemide is isolated in pure form. The purity and identity of the product are confirmed by melting point and NMR and IR spectroscopy. (Contains 2 figures and 2 schemes.) Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
10. Designing and Conducting a Purification Scheme as an Organic Chemistry Laboratory Practical (EJ823768)
Graham, Kate J.; Johnson, Brian J.; Jones, T. Nicholas; McIntee, Edward J.; Schaller, Chris P.
Journal of Chemical Education, v85 n12 p1644-1645 Dec 2008
2008-12-00
Descriptors: Organic Chemistry; Science Laboratories; Science Instruction; Science Process Skills; Science Experiments; Spectroscopy; College Science
Abstract: An open-ended laboratory practical has been developed that challenges students to evaluate when different purification techniques are appropriate. In contrast to most lab practicals, the overall grade includes an evaluation of spectral analysis as well as writing skills. However, a significant portion of the grade lies in successful execution of a purification technique. Most importantly, being able to decide upon the best approach to purification is a crucial component of the exercise. Note:The following two links are not-applicable for text-based browsers or screen-reading software. Show Hide Full Abstract
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