Organic Chemistry Teaching Laboratories Research Articles

Small-Scale Synthesis of Dibenzyl Ketone for the Organic Chemistry Teaching Laboratory

Small-Scale Synthesis of Dibenzyl Ketone for the Organic Chemistry Teaching Laboratory

Utilizing the Imine Condensation in Organic Chemistry Teaching Laboratories to Reinforce Steric Effects, Electronic Effects, and Green Chemistry Principles

Utilizing the Imine Condensation in Organic Chemistry Teaching Laboratories to Reinforce Steric Effects, Electronic Effects, and Green Chemistry Principles

Incorporating Interlab Collaborations into the Organic Chemistry Teaching Laboratories

Collaborative experiences have been widely integrated into the classroom and laboratory, with goals to build time management, communication, and team-working skills. Most reported laboratory collaborations occur between students within the same lab section, which could limit the potential benefits of these experiences. Presented herein is an organic chemistry laboratory model in which students collaborate across lab sections (i.e., interlab collaborations) to complete discovery-based, medicinal-chemistry-focused experiments. These experiences provide opportunities for students to reflect on and improve upon their team-working skills. Over the past three years, interlab collaborations have been offered at Muhlenberg College to 105 students in two types of organic chemistry courses. Assessment data, including notebook evaluation scores, peer- and self-evaluations, lab report scores, and student reflections, suggest that these experiences could help build time management, communication, organizational, and data-recording skills. These laboratories could give students a realistic view of collaborative work and allow for the intentional development and assessment of team-working skills in any introductory or upper-level chemistry laboratory. Furthermore, this model provides a framework for reducing lab section sizes by half, a change which has been needed during COVID-19, while still completing the planned lab curriculum.

Reduction of Water Waste in an Organic Chemistry Laboratory Using a Low-Cost Recirculation System for Condenser Apparatus

A low-cost and easy-to-use water recirculation system for a condenser apparatus was designed and installed in an organic chemistry teaching laboratory. Relying on gravity and a small pump for water circulation, it supplies four stations simultaneously. The water recirculation system works very well with condensers used for distillation and reflux reactions, as well as with rotary evaporators. This innovative idea has led to an annual water savings of more than 14 400 L while running only 2 lab periods per week with up to 24 students per period. Its low cost and easy installation make it convenient and easily adoptable by any laboratory where the waste of water from condensers needs to be addressed, especially in places where water scarcity is already hindering such significant scientific activities.

Independent Synthesis Projects in the Organic Chemistry Teaching Laboratories: Bridging the Gap Between Student and Researcher

Science educators strive to teach students how to be well-rounded scientists with the ability to problem solve, anticipate errors, and adapt to unexpected roadblocks. Traditional organic chemistry experiments seldom teach these skills, no matter how novel or contemporary the subject material. This paper reports on the success of a quarter-long organic chemistry laboratory experiment that takes the form of a research project designed to teach these real-life skills. Students took a three-step synthetic sequence from a literature source, and changed parameters to improve the yield. This involved library research and two levels of proposals, followed by a written report and a poster presentation. The goal was to simulate the different aspects of a research lab, from literature searches to problem-solving to presenting results. The students experienced unexpected difficulties and were graded on how they overcame these obstacles, rather than on how much they improved the yields.

Implementation of picoSpin Benchtop NMR Instruments into Organic Chemistry Teaching Laboratories through Spectral Analysis of Fischer Esterification Products

1H NMR analysis is an important analytical technique presented in introductory organic chemistry courses. NMR instrument access is limited for undergraduate organic chemistry students due to the size of the instrument, price of NMR solvents, and the maintenance level required for instrument upkeep. The University of Georgia Chemistry Department recently acquired three picoSpin desktop 1H NMR instruments for the undergraduate organic laboratories. These instruments can sit on a standard lab bench, can analyze samples without NMR solvents, and are easily maintained. In this Fischer esterification experiment, students used unknown starting alcohols to synthesize esters through Fischer esterification. Upon completion of the reaction, students identified the unknown starting alcohol via spectral analyses of the products. Over the course of 4 semesters, 704 out of 940 students (75%) correctly identified the starting alcohol and 71% of students surveyed indicated that 1H NMR spectrum was the most helpful identification tool in their analyses. This experiment established for students the utility of NMR spectral analysis and provided them with the opportunity to employ technology commonly used in academic research facilities.

Water Mediated Wittig Reactions of Aldehydes in the Teaching Laboratory: Using Sodium Bicarbonate for the in Situ Formation of Stabilized Ylides

The synthesis of alkenes using the Wittig reaction is a traditional part of many undergraduate organic chemistry teaching laboratory curricula. The aqueous medium version of the Wittig reaction presented is a reliable adaptation of this alkene formation reaction as a very safe alternative in the introductory organic chemistry laboratory. The specific aqueous Wittig reactions discussed use a one-pot reagent setup and greener methods that the students can complete within 30 min with partial workup in one laboratory period. The aqueous Wittig reactions presented have been implemented to various aldehydes and take advantage of dilute sodium bicarbonate (“baking soda”) as the only base needed for in the in situ formation of stabilized ylides. Outcomes from the implementation of the proposed aqueous Wittig procedure into the organic chemistry teaching laboratory curriculum are presented. Described also are reaction workup, purification, and analysis of products using 1H NMR and IR spectroscopy.

Waterless Condensers for the Teaching Laboratory: An Adaptation of Traditional Glassware

A simple adaptation of traditional “chemistry kit” condensers for the organic chemistry teaching laboratory is described. These waterless condensers have been employed safely with most solvents. They can be easily fabricated, stored, and used in the same manner as water-cooled condensers. These condensers were utilized in several different types of reactions and in an ethanol–water distillation providing the same product yields as reactions utilizing traditional water-cooled condensers.

A Two-Step Synthesis of the Laundry Detergent Perfume Additive β-Citronellyl Tosylate

A two-step synthesis of the compound β-citronellyl tosylate is described. The final product, synthesized by the reduction of β-citronellal with sodium borohydride followed by a solvent-free tosylation, is used as a perfume precursor and additive to laundry detergent. This project can be performed in two weeks in a typical second-year organic chemistry teaching laboratory. It exposes students to perfume chemistry, a topic not typically discussed in an organic chemistry course. Moreover, the solvent-free tosylation step of the reaction leads pedagogically to a discussion about green chemistry.

A Modern Apparatus for Performing Flash Chromatography: An Experiment for the Organic Laboratory

A modern apparatus for performing flash chromatography using commercially available, prepacked silica cartridges has been developed. The key advantage of this system, when compared to traditional flash chromatography, is its use of commercially available silica cartridges, which obviates the need for students to handle silica gel. The apparatus has been tested for its ability to perform separations that are commonly found in organic chemistry teaching laboratories, and a laboratory module that combines the techniques of thin-layer chromatography, gas chromatography, and flash chromatography is described. The performance of this new chromatography apparatus was comparable to a traditional flash chromatography column.

A Survey of the Practices, Procedures, and Techniques in Undergraduate Organic Chemistry Teaching Laboratories

A survey was conducted of four-year institutions that teach undergraduate organic chemistry laboratories in the United States. The data include results from over 130 schools, describes the current practices at these institutions, and discusses the statistical results such as the scale of the laboratories performed, the chemical techniques applied, the instrumentation available, the laboratory equipment used, the chemistry topics covered, the way chemical safety is presented, and how chemical waste is handled. These results provide a “snapshot” of the current state of the undergraduate organic teaching laboratory.

Simple Microwave-Assisted Claisen and Dieckmann Condensation Experiments for the Undergraduate Organic Chemistry Laboratory

The Claisen condensation and its intramolecular variant the Dieckmann condensation are classic reactions studied in undergraduate organic chemistry courses because of their importance in organic synthesis and biochemical transformations. The growth in the use of microwave technology in both the synthetic and teaching laboratories warrants the modification of existing methodologies to incorporate this technology. This article presents simple microwave-assisted procedures for carrying out Claisen and Dieckmann condensation reactions that are suitable for organic chemistry teaching laboratories that utilize microwave technology. Although solvents can be used, the procedure is amenable to solvent-free conditions that promote green chemistry.

A Green, Guided-Inquiry Based Electrophilic Aromatic Substitution for the Organic Chemistry Laboratory

We developed an alternative electrophilic aromatic substitution reaction for the organic chemistry teaching laboratory. The experiment is an electrophilic iodination reaction of salicylamide, a popular analgesic, using environmentally friendly reagents—sodium iodide and household bleach. Further, we designed the lab as a guided-inquiry experiment, asking the students first to predict the orientation of the substitution reaction. After synthesizing the product, the students are asked to determine its structure using FT-IR spectroscopy. The choice of this method of characterization was intentional because of the utility of infrared spectroscopy in determining substitution patterns on aromatic rings and also because it requires students to analyze the fingerprint region of the spectrum. Given that most classroom instruction on IR focuses on functional group determination, we believe this is an added benefit to this experiment.

On the Successful Use of Inquiry-Driven Experiments in the Organic Chemistry Laboratory

The inquiry-driven approach to laboratory teaching allows students to participate effectively in the process of science. This article provides examples of guided-inquiry and design-based experiments and explores strategies for implementing them to enliven the modern organic chemistry teaching laboratory in a variety of educational environments. We discuss factors important to the success of inquiry-driven experiments and projects in four categories of institutions, as well as the potential difficulties in implementing them, including faculty participation, TA training, post-laboratory discussions, instrumentation, and necessary background materials.

A extração de cafeína em bebidas estimulantes: uma nova abordagem para um experimento clássico em química orgânica

Caffeine extraction procedures from water soluble and water insoluble materials for preparing stimulating beverages are described. Water soluble materials used were instant tea and coffee and water insoluble materials were, among others, guarana powder and mate leaves. The extraction of caffeine from water soluble materials, especially instant tea, is more suitable for an organic chemistry teaching laboratory than the classic experiment using tea leaves, due to the economy of time and a larger amount of extracted caffeine. The procedure is time-saving and requires only a four-hour period. The experiments illustrate the extraction process as used in undergraduate organic chemistry laboratories.

Sampling Technique for Organic Solids in IR Spectroscopy: Thin Solid Films as the Method of Choice in Teaching Laboratories

Techniques for sampling solid organic compounds for FTIR spectroscopy are briefly compared and contrasted. One method, which we call thin solid films, stands out as the method of choice in undergraduate teaching laboratories. Thin solid films are easy to prepare and inexpensive because the sample preparation does not require special equipment. The spectra obtained are of good to excellent quality. Some instructors may not have heard of the technique because it is under-emphasized in most spectroscopy and organic laboratory technique textbooks. The method helps to maximize student use of the current generation of FTIR spectrometers, which are becoming standard equipment in most university-level organic chemistry teaching laboratories.