GEMs Database Archive

An aqueous Suzuki reaction is described which highlights the facile preparation of a non-steroidal anti-inflammatory (NSAID) drug analog under green conditions. While palladium-catalyzed cross-coupling reactions are common in most modern organic chemistry labs, they are often performed with hazardous solvents and large amounts of corrosive additives. Undertaken at the mid-undergraduate level ...

As landfills begin reaching their capacity and waste generation skyrockets, the world is being forced to take a harder look at recycling. Because it is currently estimated that plastics make up a quarter of landfill space, the recycling of plastics is a hot, current topic.

In this lab, a common plastic, polyethylene terephthalate (PET), will be depolymerized by a simple hydrolysis reaction ...

The alkylation of aromatic compounds is a very important industrial process. Typically these alkylations are performed using strong Lewis acids like aluminum trichloride as catalysts. However, the use of these catalysts often requires an aqueous work-up to remove the aluminum and also leads to mixtures of products due to carbocation rearrangement.

By using graphite this greener alkylation ...

Because of the ubiquity of polymers, chemists are looking for ways to make polymers renewable, biodegradable, and with less waste. In this laboratory chemistry students will have the opportunity to make poly(aspartate), a polymer that fulfills all the abovementioned goals.

The synthesis of this condensation polymer starts by simply heating neat aspartic acid for two hours to form poly(succinimide ...

This exercise demonstrates the regioselectivity of substituted aromatic systems while reducing the amount and hazards of the waste produced by the class. Although typical iodinations involve either high amounts of derivatization (i.e., nitration, then reduction to aniline, formation of diazonium, then ionization) or use of hazardous/expensive reagents (iodine and mercury acetate, bis(pyridine ...

This experiment teaches students the concept of colligative properties using renewable, benign, and biodegradable materials. Rather than using conventional solvents with high cryoscopic constants (which are oftentimes aromatics), fatty acids are used to explore freezing-point depression. By monitoring the change in freezing points of solutions with varying solute concentrations, students will be ...

This demonstration shows students a long-lasting, chemiluminescent reaction in light sticks without the toxic solvents. The instructor must prepare the chemiluminescent reagent, divanillyl oxalate, in a one-step synthetic procedure or can have the students prepare the reagent as part of an organic chemistry experiment.

Solvents acceptable for the chemiluminescence reaction are ethyl acetate or ...

This laboratory experiment features the palladium-catalyzed Heck synthesis of (E)-4-acetylcinnamic acid from 4-iodoacetophenone and acrylic acid by mid-level undergraduates. Traditional Heck reaction organic solvents (e.g. acetonitrile) and base (e.g. triethylamine) are replaced by water and sodium carbonate respectively. This approach introduces fundamentals of green chemistry (aqueous and ...

The transformation of ketones into esters using peroxy acids was first reported in 1899. Since then, the Baeyer-Villiger oxidation has found itself an integral part of the organic chemist's toolkit. This modified Baeyer-Villiger is a great example of how a classic reaction can be made significantly greener. By eliminating the solvent you can avoid the hazards associated with dichloromethane (the ...

In this laboratory experiment, students explore the use of an immobilized Ni[P(OEt)3]4H2SO4 catalyst system to study the isomerization of 1-octene to trans- and cis- 2-octene. Nafion-H+ is a solid acid ion exchange polymer that both activates the air-sensitive transition metal catalyst and immobilizes the cationic species that can be characterized by UV-vis spectroscopy within the polymer matrix ...

This article provides a rationale and stepwise process for evaluating and improving the "greenness" of an undergraduate organic chemistry laboratory curriculum. After emphasizing the educational value of sharing this process with students, effective risk assessment is discussed as an important tool for both evaluating and redesigning laboratory exercises. The greening process is illustrated by ...

This experiment highlights both the importance of palladium-catalyzed coupling reactions and the need for finding greener solvents. The aqueous-phase coupling of iodobenzene and diethylphosphite is a great example of how a reaction can be made greener with a relatively straightforward modification. By simply sulfonating triphenylphosphine, students will be synthesizing a water-solubilizing ligand ...

In 1995 President Clinton introduced the Presidential Green Chemistry Challenge (PGCC) Awards Program. The program was created to acknowledge companies and individuals who research and develop technologies "that promote pollution prevention and industrial ecology through a new EPA Design for the Environment partnership with the chemical industry." In this article, Dr. Michael Cann discusses two ...

Chiral compounds can have unique properties and are becoming increasingly important in pharmaceutical, chemical, and agricultural industries. In this laboratory exercise, students compare and contrast chemical vs. enzyme-mediated procedures for introducing chirality into a molecule and gain experience with the principles and experimental techniques used to prepare and separate enantiomers. Over ...

In this set of experiments, students will be introduced to condensation reactions, green chemistry, and cocrystal-controlled solid-state synthesis. This type of solid-state synthesis is performed by first making cocrystals of the two reactants (in this case an anhydride and an amine) which brings the reactive functional groups in close proximity to one another, allowing for a reaction to occur ...

This experiment demonstrates chemoselectivity in various reaction conditions. The mono or di-methylation of 1,8-dihydroxy-9,10-anthraquinone can be controlled by either refluxing the reagents in tetraglyme or by simply heating without solvent. Also, this ether synthesis has been made greener by eliminating flammable THF and dangerous sodium hydride and by using a less toxic methylating agent. ...

The determination of the formula of a hydrate is an experiment that introduces students to many fundamental chemical concepts including stoichiometry, the notion of a mole, and nomenclature. In this experiment, the authors replaced the previously used calcium and barium salts because the latter is considered poisonous and tumorigenic, and both were considered waste after only one use. Instead ...

This lab teaches important basic chemistry skills in the context of utilizing renewable feedstocks. In a three-week series of experiments, students will synthesize biodiesel from peanut oil and determine the heat of combustion, density, and cloud point of their product. Students will then use this information to evaluate the viability of biodiesel when compared to petroleum diesel.

Physical ...

In order to instill an increased awareness of sustainability issues in future generations of scientists, the concepts and content of science courses must be changed. While important chemical concepts must be preserved, outdated, dangerous, and wasteful chemistry should be replaced by current, more sustainable alternatives. With these beliefs in mind, six German universities combined forces and ...

Biocatalysis and biotransformations are important alternatives to consider when one is looking to substitute a conventional method with a greener one. One of the many advantages of using biotransformation as a synthetic method is that they are usually done in water and at ambient conditions. In addition, the reagents themselves are readily available, safe, and inexpensive to both buy and dispose ...

Oxidations and reductions are among the most commonly performed reactions in organic chemistry. Consequently, it is vital that redox chemistry is taught in our undergraduate chemistry courses. Unfortunately, many oxidations are classically and currently performed with toxic, carcinogenic chromium (VI) metals and require time-consuming and wasteful aqueous work-up.

All of these abovementioned ...

This laboratory exercise teaches students some of the principles of green chemistry while simultaneously introducing them to several traditional organic reactions. All the reagents used in the experiment are relatively safe and the avoidance of volatile organic solvents reduces cost, waste, and hazards. The ultimate pyridine product is reached in three steps. The first step is the solventless ...

Qualitative analysis of inorganic salts and mixtures is a common component of high school, undergraduate, and graduate-level curricula. The hydrogen sulfide scheme given by Fresenius is a widely accepted scheme used for studying Le Chatelier's Principle, the common-ion effect, and solubility products. However, H2S is deadly even at low air concentrations, can cause permanent physiological damage ...

The Blue Bottle demonstration, involving the colorful redox cycling of methylene blue, is often used to introduce and illustrate the scientific method to younger science students and to study reaction rates and mechanisms with advanced high school and university students. This paper describes a greener blue bottle demonstration that reduces the total amount of material used in the demonstration ...

While the Wittig reaction is often used as an example of a reaction with poor atom economy, it is still important to recognize that any reaction, the Wittig included, can be made greener. This solvent-less Witting not only eliminates the hazards associated with traditional solvents but also uses reagents with little or no known toxicity. This is particularly notable given the relatively high ...

Many people would argue that one of the ultimate goals of green chemistry should be to solely use water as a solvent if a solvent is needed at all. For reactions where water is not an option, a choice must be made from a wide variety of organic solvents. Recently room temperature ionic liquids (RTIL) have been receiving a lot of attention because of their chemical and thermal stability, low vapor ...

Analysis of trace metals and organic substances often relies on the use of
organic solvent-based extractions. In this laboratory exercise, students
will use analytical chemistry to determine heavy metals from water samples using a greener, micelle-mediated extraction procedure called cloud-point extraction. Water samples are treated with a chelating agent, ammonium pyrrolidine dithiocarbamate ...

Heterocyclic compounds have a wide range of applications and properties. They are often antimicrobial agents, can inhibit specific enzymes, and are generally useful in organic synthesis. This experiment provides instructors with a variety of heterocyclic compounds that can be synthesized quickly with the aid of microwaves. While not a lot of Microwave-Assisted Organic Synthesis (MAOS) is taught at ...

Microwave-assisted organic synthesis is becoming a more common laboratory practice. The advantages of using microwave-assisted synthesis include shortened reaction time, lower energy costs, and cleaner reactions. This particular experiment explores a much greener Wittig reaction that doesn't require an inert atmosphere, a strong base (i.e., butyl lithium), or even a solvent. In addition to these ...

Sustainability is an undeniably important issue that any educator who teaches green chemistry must at some point address. This collection of web resources is not only a great reference to aid in curriculum preparation, but it also briefly discusses some of the challenges that the world faces in light of limited resources and a growing population.

The review includes a short summary of green ...

Coumarins represent an important class of natural and synthetic derivatives with interesting biological activities. The 3-carboxycoumarins have been intensely studied because new functionalities can be easily added via the carboxyl group. During this laboratory exercise, students prepare 7-hydroxy-3-carboxycoumarin using a one-pot, multi-step procedure in the absence of organic solvents. By using ...

An organic chemistry laboratory experiment illustrating the oxidation of primary and secondary alcohols to their corresponding aldehyde or ketones, respectively, is described. The procedure uses 30% aqueous hydrogen peroxide in the presence of a tungsten catalyst (sodium tungstate) using phase transfer catalysis. The described experiments illustrate basic organic reaction chemistry and techniques ...

One of the main advantages of doing green chemistry is that it can often be done on the benchtop without the need for a fume-hood. In this experiment water and ethanol are the only solvents used for both the reaction and purification steps and oxone is a safe oxidant whose only by-product is potassium sulfate.

The oxidation of aromatic aldehydes using oxone allows instructors to discuss green ...

Applications of organic chemistry to modify the structure and surface properties of materials are becoming increasingly important and interdisciplinary as the dimensions of modern materials decrease. This laboratory exercise illustrates how macroscopic material properties can be modified with self-assembled monolayers and organic thin-film patterning. Using an inexpensive gold on vinyl substrate ...

There are many tools that a synthetic organic chemist can use to synthesize amines; one of which is reductive amination. This common method of introducing the amine functionality is especially crucial for the synthesis of pharmaceuticals and biomolecules.

A typical reductive amination is a one-pot reaction involving a solvent, an aldehyde or ketone, an amine, and a weakened reducing agent. This ...

Chalcones represent a group of compounds with interesting biological activities that are formed from an aldol condensation between a benzaldehyde and an acetophenone in the presence of NaOH as a catalyst. Although typically synthesized using organic solvents, in this exercise students prepare 20 different chalcones using a solventless procedure. The scale of these reactions can be easily modified ...

Carbon-carbon bond formation is arguably one of the most crucial transformations in organic chemistry. In this experiment, students will simultaneously transform carbonyl groups into olefins via the Wittig Reaction while learning principles of green chemistry. While the Wittig is not normally known for its "greenness" (due to its poor atom economy), this lab seeks to bolster the reaction's green ...

This series of exercises enforces green chemistry concepts while also introducing students to the balancing of equations and stoichiometry. The concept of conservation will likely already be familiar to most students, but these drills give students a chance to analyze different synthetic pathways and decide which path is the most green. The three target compounds given in this article are aluminum ...

It is well known that epoxides can undergo rearrangement to yield carbonyl compounds in the presence of a Lewis acid catalyst. Classically these catalysts have included a wide variety of compounds some of which are hazardous and harmful. The impetus for this experiment came from a previous lab taught by the authors in which toxic, corrosive boron trifluoride etherate was used to catalyze the ...

This lab demonstrates a pericyclic reaction that is popular in undergraduate texts, the Diels-Alder reaction, and does so in the context of using water as a safe, alternative solvent. Adapted from work published by Larsen and Grieco in 1985, this experiment makes use of the synthesis of N-benzyl-2-azanorbornene to present green chemistry to students. Not only is this very atom-economical reaction ...

A special topics course on "Towards the Greening of Our minds" is offered every other spring at Washington College. This course is designed for science majors who have taken general and organic chemistry and are interested in the future of the planet. The ultimate goal of the class is for students to use green chemistry as a way to critically evaluate environmental policy. Over the course of the ...