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1.

Carboxymethylcellulose-supported Palladium Nanoparticles Formed in situ for Suzuki-Miyaura Coupling Reaction Xiaojian Liao, Yuemin Zhou, Fu Tang, Xia Lin, Yiqun Li World Journal of Organic Chemistry. 2021 9 (1). doi: 10.12691/wjoc-9-1-3 Keywords: organic experiment, green chemistry, Suzuki-Miyaura reaction, supported catalyst, palladium nanoparticles, carboxymethylcellulose, upper-division undergraduate, Hands-On Learning /manipulatives Context: A green experiment is described here for direct fabrication of carboxymethylcellulose-supported palladium nanoparticles (PdNPs@CMC) in situ through a simple self-assemble and self-reduction process between carboxymethylcellulose (CMC-Na) and PdCl2 solution. The PdNPs@CMC was well characterized by ICP, UV-Vis, XPS, FTIR, SEM, and TEM techniques. The in situ synthesized PdNPs@CMC was proved to be an efficient catalyst for Suzuki-Miyaura coupling reaction under mild aerobic conditions. The superior catalytic performance of PdNPs@CMC is attributed to the coordination with carboxyl groups (−COO−) and free hydroxyl groups (−OH) as well as polymeric capping effect of CMC. Moreover, the catalyst showed no significant loss of its activity at least three consecutive cycles. This laboratory class is involved in the preparation and characterization of PdNPs@CMC as well as its catalytic application in Suzuki−Miyaura cross coupling reaction under green conditions. This laboratory class is suggested to divide into two parts. The first part includes the fabrication of catalyst in situ through a self-assemble and self-reduction of Pd(II) with CMC−Na, and characterization of the as-prepared catalyst using various techniques. The second part employs the resulting catalyst to perform a microscale Suzuki-Miyaura reaction, recycling of catalyst, and characterization of the product. By design, this comprehensive experiment set up for the third-year undergraduate, and aim to make students comprehend the concept of ion-exchange reaction, reduction reaction, carbon-carbon coupling reaction, supported catalysts, nanoparticles, and green chemistry as well as train the fundamental operation capability of students, and improve their experimental skills. Abstract Full Text (PDF) [Epub] Full Text (HTML)

2.

Qualitative and Quantitative Analyses of Synthesized Short-Chain Fatty Acid Phenyl Esters Using Fourier-Transform Infrared Spectroscopy Ronald P. D’Amelia, Masashi W. Kimura, Marie-Claire Villon World Journal of Organic Chemistry. 2021 9 (1). doi: 10.12691/wjoc-9-1-2 Keywords: ab initio, computational chemistry, density functional theory, esterification, Fourier-transform infrared spectroscopy, Hands-On Learning , phenyl esters, phenyl ester mixtures, quantitative analysis, synthetic organic chemistry, undergraduate laboratory experimente Context: Fourier-transform infrared spectroscopy (FT-IR) is a widely used technique to qualitatively determine the molecular structure of organic compounds; however, using quantitative FT-IR (qFT-IR) for the compositional analyses of mixtures is less common. To reinforce instrumental use in undergraduate laboratories, we have devised a multipart experiment that not only combines the qualitative and quantitative aspects of FT-IR but also exposes students to computational and synthetic organic chemistry. The objectives of this experiment are to synthesize a series of phenyl esters (PhEs) of various molecular weights; use qualitative FT-IR to characterize and compare the synthesized products with standards, databases, and with theoretical spectra computed using the cost-efficient B97-3c functional; and determine the weight percent (wt. %) composition of a binary mixture. We report on the methodologies used to synthesize and purify four PhEs; characterize them using FT-IR, conduct theoretical calculations and compare their FT-IR spectra with experimental ones; and determine the wt. % composition of phenyl acetate (PhAc), phenyl propionate (PhPr), phenyl butyrate (PhBu), and phenyl hexanoate (PhHex) in binary mixtures ranging from 0% to 100%. The results show a strong, linear correlation of gravimetrically calculated wt. % composition of a selected compound in a binary mixture using qFT-IR. This experiment demonstrates the applicability of qFT-IR as an educational tool for the undergraduate chemical laboratory and combines four different branches of chemistry: computational, instrumental, organic, and analytical. Abstract Full Text (PDF) [Epub] Full Text (HTML)

3.

Spectroelectrochemistry of Electrochromic and Electroluminescent Substances with Screen-Printed Electrodes and with an Optically Transparent Platinum Mesh Electrode Achim Habekost World Journal of Chemical Education. 2020 8 (2). doi: 10.12691/wjce-8-2-3 Keywords: second-year under graduate, laboratory instruction, physical chemistry, Hands-On Learning / manipulatives, electrochemistry, spectroscopy Context: Spectroelectrochemistry of Electrochromic and electroluminescent substances shows a strong correlation between electrochemical reactions on electrodes and changes in absorbance or luminescence adjacent to the electrode. This was demonstrated by the well-known substances methylviologen and tris (2,2’-bipyridyl) dichloro-ruthenium [Ru (bpy)3]2+. The experimental setup used a conventional potent iostat connected to a fiber spectrometer. Different commercial spectroelectrochemical cells were used: A thin-film absorption cell with a platinum mesh working electrode and as pecular reflection/transmission cell with different screen-printed electrodes. For luminescence measurements, a conventional quartz cuvette with the platinum mesh electrode was used. All cells were inserted into commercial cell holders with connectors for optical fibers. Spectroelectrochemistry becomes increasingly important as an analytical method. In addition, the empirically observed didactical problems of misunderstanding electrochemical electrode reactions can be overcome by visualizing the electrode processes in spectroelectrochemical measurements. The procedures followed in these experiments were designed for typical undergraduate students in electrochemistry. Abstract Full Text (PDF) [Epub] Full Text (HTML)

4.

Synthesis of a Crosslinked Epoxy Resin Medallion in the Organic Chemistry Laboratory Katherine W. Stickney, Joe C. Burnell, John T. Wyeth World Journal of Chemical Education. 2019 7 (4). doi: 10.12691/wjce-7-4-1 Keywords: interdisciplinary/multidisciplinary, laboratory instruction, organic chemistry, polymer chemistry, second-year undergraduate, upper-division undergraduate, Hands-On Learning /manipulatives, epoxides, polymerization Context: Polymer synthesis has a limited inclusion in most organic chemistry lecture curricula, so emphasizing the concepts of polymer chemistry in a laboratory setting gives students hands-on experience in new content and broadens the scope of the class. The details and outcomes of a robust and well-developed laboratory procedure for the synthesis of a crosslinked epoxy network polymer are described. This experiment has been a part of a first-semester, introductory undergraduate organic chemistry laboratory curriculum for more than two decades and has positively impacted over eight hundred students. The experiment had the unique aspect that students cured the resin in a round, seven-centimeter mold, forming a hardened epoxy disk. This disk, or medallion, was decorated in two different ways: first, a design was etched into the mold before curing to form a permanent imprint; second, the final epoxy medallion was decorated, post-cure, with colored permanent markers and glitter glue. After this laboratory experiment, students took home a durable ornament as a memento of their first-semester organic chemistry laboratory course. Abstract Full Text (PDF) [Epub] Full Text (HTML)

5.

An Undergraduate-Level Electrochemical Investigation of Gold Nanoparticles-Modified Physically Small Carbon Electrodes Shaneel Chandra, Wycliff Tupiti, Sevlin Singh, Zafiar Naaz, Pritika K. Kishor, Archana Goundar, Malina Fakraufon, Surendra Prasad World Journal of Chemical Education. 2016 4 (5). doi: 10.12691/wjce-4-5-1 Keywords: upper-division undergraduate, laboratory instruction, physical chemistry, Hands-On Learning , electrochemistry, materials science, surface science Context: This paper reports an undergraduate experiment based on analytical chemistry, electrochemistry and materials science of carbon microelectrodes. The modification of the electroactive surface of the carbon microelectrode was done using gold nanoparticles electrodeposited from gold solution. To determine the changes on the surface, the electrode was subjected to simple optical microscopy. Next, the electrode was characterized using fast-scan cyclic voltammetry of two known electrochemical redox markers: hexaamineruthenium(III) chloride and potassium hexacyanoferrate (III), i.e. potassium ferricyanide. The redox behavior of both markers demonstrated the change in electrode surface. After modification, the ferricyanide reduction peaks were observed to increase significantly, as a consequence of accelerated electron transfer. Furthermore, changes in wave slope and half-wave potentials (E½) of the redox waves also confirmed an altered electrode surface that students can logically trace back to the modification. The electrode tip dimension was also determined using a modified form of the Cottrell equation, confirming the tip size to be 2.0 µm. The discussion of these results enables an understanding of electrochemistry, analytical chemistry and materials chemistry, and presents an excellent opportunity to apply these in an undergraduate setting. Abstract Full Text (PDF) [Epub] Full Text (HTML)

6.

Demonstrating Sustainable Biomass Utilization and Processing Using Ionic Liquids – An Introduction to Undergraduate Chemistry Laboratories Daniel Rauber, Michael Conrad, Johannes Huwer, Harald Natter, Rolf Hempelmann World Journal of Chemical Education. 2017 5 (5). doi: 10.12691/wjce-5-5-3 Keywords: ionic liquids, biomass, polymer chemistry, Hands-On Learning , green chemistry, material science, solvents Context: A more sustainable, greener chemistry aiming at the utilization of renewable resources is a main research focus to reduce human environmental impact. Unfortunately, there is a lack of powerful, environmentally benign solvents for the two most abundant renewable biopolymers, cellulose and lignin. Ionic liquids are here introduced to undergraduate chemistry laboratories as recyclable, tunable solvents for the dissolution and processing of biomass in the form of wood and its components to create alternative processes that are safer as well as waste- and additive-free. These experiments emphasize the principles of green chemistry and demonstrate the scope and potential of ionic liquids for the production of novel, biodegradable materials from renewable resources. Abstract Full Text (PDF) [Epub] Full Text (HTML)

7.

Cyclic Voltammetry - A Versatile Electrochemical Method Investigating Electron Transfer Processes N. Aristov, A. Habekost World Journal of Chemical Education. 2015 3 (5). doi: 10.12691/wjce-3-5-2 Keywords: third-year undergraduate, analytical, electrochemistry, Hands-On Learning /manipulatives, laboratory instructions Context: Three experiments are presented to introduce students to the capabilities of cyclic voltammetry (CV) for finding redox couples suitable for, e.g., battery development. The systems chosen involve only one-electron transfer, but already display complex behaviours that can be delineated with CV as being reversible, quasi-reversible, or irreversible, and the rate constants for the electron transfer can be estimated by the theory of Nicholson and Shain. Abstract Full Text (PDF) [Epub] Full Text (HTML)

8.

Monitoring pH Using Alizarin-modified Commercial Screen-printed Electrodes Achim Habekost World Journal of Chemical Education. 2020 8 (4). doi: 10.12691/wjce-8-4-4 Keywords: second-year undergraduate, demonstration, Hands-On Learning /manipulatives, electrochemistry, analytical chemistry Context: A pH-sensor based on alizarin-modified screen-printed multiwalled carbon nanotubes (MWCNT-SPE, Orion High Technologies) imbedded in Nafion® shows a linear dependence between the oxidation potential and the pH from pH 0 to pH 10. This modified MWCNT-SPE is compared to a commercial alizarin SPE (DRP 110ALI, Metrohm - DropsSens). In addition to this technical application, these pH sensors seem to be a good didactic alternative to the widely used pH glass electrode, which many students find hard to understand. Abstract Full Text (PDF) [Epub] Full Text (HTML)

9.

Application of Differential Scanning Calorimetry in an Organic Chemistry Laboratory Course: Development of a Binary Phase Diagram of Cis/Trans-1, 2-Dibenzoylethylene Ronald P. D’Amelia, Brett Johnson, Shivnath Mazumder World Journal of Chemical Education. 2017 5 (2). doi: 10.12691/wjce-5-2-4 Keywords: upper-division undergraduate, laboratory instruction, organic chemistry, Hands-On Learning , instrumental methods, phases diagrams, eutectic, cis/trans 1,2 dibenzoylethylene, Differential Scanning Calorimetry Context: In organic chemistry lab it is important to give students hands-on experiences to help them further their understanding of important chemistry topics. Binary phase diagrams incorporate many of these topics into a single graph. Differential Scanning Calorimetry (DSC) has been shown to produce data to make binary phase diagrams for alloys; however, it is more difficult to produce these diagrams using non-metal organic compounds. The purpose of this experiment was to determine if the DSC could be used to give students a challenging, yet doable experiment to prepare a binary phase diagram and determine the eutectic composition for the mixture of cis/trans-1,2-dibenzoylethylene. The conclusions from this work are: (i) The eutectic composition for cis/trans-1,2-dibenzoylethylene is at the weight percent of 30% cis and 70% trans which corresponds to an onset melting temperature of 93.5°C; (ii) as the cis increased from a weight percent of 30% the melt temperature also increased; (iii) as the trans increased from a weight percent of 70% the melt temperature also increased; (iii) the DSC produced sufficient data necessary to develop a binary phase diagram of peak melt temperatures vs the weight percent of the cis isomer; (iv) the DSC could be incorporated into an organic chemistry lab to enhance student’s knowledge of important topics while giving them an experience working with advanced laboratory thermal instruments. Abstract Full Text (PDF) [Epub] Full Text (HTML)

10.

Mimicking Nature – Imitating Ion Carriers Using Crown Ethers in a Vertical Pressman Cell Philipp Meyer, Stefan Kubik, Amitabh Banerji World Journal of Chemical Education. 2026 14 (1). doi: 10.12691/wjce-14-1-3 Keywords: high school, organic chemistry, Hands-On Learning , crown ethers, ionophores/ ion carriers, membranes Context: Valinomycin, an antibiotic ionophore (ion carrier), is a functional analog of the cyclic hexaether [18] crown-6 (18C6). Both valinomycin and 18C6 molecules form lipophilic complexes with alkali metal ions. Hence, upon addition of valinomycin or 18C6, alkali metal salts become soluble in non-polar organic solvents. The ability to complex cations allows valinomycin molecules to transport these ions across cell membranes. Since 18C6 molecules bind alkali metal cations in a similar way, by wrapping them in a “greasy coat”, cell transport processes by valinomycin can be imitated using the more cost-efficient and less hazardous 18C6. In a simple test tube experiment, cell conditions are mimicked by means of a triphasic system consisting of an aqueous magnesium sulfate (MgSO4) solution (bottom phase) and an aqueous potassium permanganate (KMnO4) solution (top phase) which are separated by a methyl benzoate phase serving as a liquid membrane. If a solution of 18C6 is injected into the methyl benzoate phase of this “vertical Pressman cell”, a salt transfer from the upper aqueous phase to the bottom phase can be observed, modelling the effect of valinomycin in living cells. Appropriate simplifications for use in schools are discussed and animations are provided to illustrate the ionophore-facilitated cell transport. Abstract Full Text (PDF) [Epub] Full Text (HTML)