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Interested in learning more about green chemistry at New Orleans? You can find symposia on green chemistry and sustainability by searching the online program or mobile app, or by browsing Technical Sessions, click on Filter by Themes, check and apply green chemistry or sustainability.

 

Highlights

 

This year marks the 20th anniversary of “Green Chemistry: Theory and Practice” by Paul Anastas and John Warner. This work identified twelve principles for practicing chemistry in a way that reduces or eliminates hazardous substances and waste. Its publication promoted greater awareness that chemists play a key role in creating a more sustainable future, and this message inspired, and continues to inspire, academic research and industrial application. We invite you to celebrate this anniversary in a full-day session in honor of Anastas and Warner entitled, “State of the Art: Two Decades of the 12 Principles of Green Chemistry.” Monday, March 19, a.m. and p.m. in Blaine Kern E, New Orleans Marriott

 

The ACS GCI Pharmaceutical Roundtable (GCIPR) is offering several opportunities to learn and engage at this Spring National Meeting:

  • Join a GCIPR workshop entitled “Essential Green Chemistry Tools and Techniques for Pharmaceutical Scientists,” that will equip practicing chemists and graduate students with practical tools, methods and metrics. The free workshop is Sunday, March 18, 1:30 -4:30 p.m. in Gallier B, Sheraton New Orleans. Space is limited. Register for the workshop in the meeting registration process, or email gci@acs.org. There is a small deposit required to secure your seat, refunded upon attendance of the workshop.

  • Join the GCIPR for a full day Wednesday to discuss continuous flow, green solvents, biocatalysis, novel high-throughput enabling technologies and more in an I&EC session on “Innovative Green Processing Technology & Chemistry” on Wednesday, March 21, 2018, 8-11:45 a.m. and 1-4:05 p.m. in Louisiana II, Loews New Orleans Hotel.

  • As the market for biopharmaceuticals grow, so does the environmental footprint of their manufacture. The GCIPR Biopharma team has developed a Process Mass Intensity (PMI) tool for biologics and benchmarked environmental impact across companies. Learn more about this study in BIOT 80, “Mining data to improve environmental impact of biomanufacturing,” as well as comparative analysis of different types of manufacturing processes for a monoclonal antibody using PMI at Merck (BIOT 554), and GSK’s analysis of using the Carbon Footprint Calculator as an additional assessment tool at GSK (BIOT 456).

 

Want to learn how to integrated green chemistry into your ACS Student Chapter? Don’t miss the CHED session, “Green Chemistry Student Chapters: Stories of Success” on Sunday, March 18, 1:30 p.m. at Blaine Kern B, New Orleans Marriott Convention Center.

 

Join us to congratulate the 56 ACS Student Chapters who are receiving an award for their green chemistry activities at the Student Awards Ceremony on Sunday night.

 

Learn how you can integrating green chemistry into the curriculum, classroom, lab and student research activities. This CHED day-long session, “Green Chemistry Theory and Practice: Food, Energy, & Water Sustainability,” covers a range of successful examples and initiatives of interest to the community. Drop by Tuesday, March 20, 2018 from 8:30-11:40 a.m. and 1:30-4:45 p.m. in the Blaine Kern B, New Orleans Marriott Convention Center.

 

The fun never ends! Wednesday evening starts the ENVR session “Green Chemistry & the Environment” full of theoretical and experimental green chemistry research in biocatalysis, chemical engineering, toxicology and more. The session is Wednesday, March 21, 6 p.m. and Thursday, March 22 at 8:30 a.m. in Hall D, Ernst N. Morial Convention Center.

 

Don’t miss these special lectures:

  • ORGN: ACS Award for Affordable Green Chemistry: Symposium in honor of B. Frank Gupton & D. Tyler McQuade on Monday, March 19, 1 p.m., La Nouvelle Orleans Ballroom C, Ernest N. Morial Convention Center.

  • There are three 2018 ACS Sustainable Chemistry & Engineering Journal Lectureship Award symposia:
    • I&EC: Symposium in honor of Fengqi You – Monday, March 19, 1 p.m. in Feliciana East, Loews New Orleans Hotel
    • CELL: Symposium in honor of Rafael Luque Monday, March 19, 8 a.m. in St. Landry, Loews New Orleans Hotel
    • CELL: Symposium in honor of Ning Yan – Tuesday, March 20, 8 a.m. in St. Tammany, Loews New Orleans Hotel

 

Last but not least, be sure to visit ACS GCI in the Expo, Booth #646

  • Come by and spin our prize wheel to win green chemistry swag and prizes!
  • Learn about the Design Principles of green chemistry and see how you can apply them to our studies, research and work.
  • Stop by the ACS store and pick up a green chemistry t-shirt, pint glass, endangered elements poster and more!
  • Follow @ACSGCI for live updates. Win prizes! Have fun! Learn more about green chemistry!

Rafael Luque, Professor, Departamento de Quimica Organica, Universidad de Cordoba, Spain

 

Mechanochemistry deals with chemical transformations induced by mechanical means such as compression, shear or friction. In mechanochemical processes, the energy required for the activation of chemical reactions is usually provided by mechanical force as similar to thermochemistry, photochemistry or electrochemistry where energy is provided by heat, light or electrical potential, respectively.

 

Importantly, the solvent often plays a key role in energy dispersion, dissolution/solvation and transportation of chemicals in conventional chemical synthesis. Mass and energy transport may also be hampered in solventless reactions. The efficient mixing process under ball milling or grinding can offer an effective way out of this problem, enabling the reactions between solids/powders or solidified reagents in solvent-free conditions.

 

Solventless, “dry milling” mechanochemical approaches, highly advantageous for certain applications, can also be replaced by “liquid-assisted grinding” (LAG) as bridging alternative to minimize the use of solvents in mechanochemical syntheses. In contrast to “dry milling”, LAG may offer advantages such as greater time efficiency, enhancing molecular mobility and can result in the discovery of new or improved reactivity and (nano)materials.

 

Mechanochemical processes have a number of relevant advantages as compared to conventional syntheses including 1) an inherently “greener” approach to conduct chemical/materials syntheses (solvent-free or solvent-limited); 2) improved energy efficiency and solvent use (up to 1000-fold reduction/improvement); 3) swiftness and remarkably faster than solution synthesis (allowing a rapid screening of synthesis conditions for materials and/or chemical reactions); 4) wider choice of starting materials and possibilities (e.g. cheaper and more environmentally friendly reactants); 5) high yielding and facilitating/avoiding purification/isolation steps.

 

In view of these relevant advantages, the potential of mechanochemistry is significant, not only in the design of advanced and new (nano)materials for applications in multiple fields (adsorption, catalysis, energy storage, sensing, etc.) but also in the promotion of chemical reactions (mechanocatalysis). Some relevant examples are given in the following sections.

 

Design of advanced (nano)materials

 

Mechanochemistry has already paved the way to the design of advanced and new functional (nano)materials which includes (but not limited to) perovskites, spinels, metal-organic frameworks (MOFs), supported nanoparticles on porous materials, bionanoconjugates an electrodes/biosensors (i.e. laccase@TiO2@C) and many more. The possibilities are enormous and mechanochemistry was found to provide access to new structures, enhanced properties and improved activities in certain applications (e.g. catalysis).

 

Organic-inorganic hybrid perovskites are materials that have attracted significant attention due to their extraordinary optoelectronic properties with applications in the fields of solar energy, lighting, photodetectors, and lasers. The rational design of these hybrid materials is a key factor in the optimization of their performance in perovskite-based devices. These could be successfully synthesized using a highly efficient, simple, and reproducible solventless mechanochemical approach. Materials could be synthesized 1) in large amounts (multi-gram scale), 2) as polycrystalline powders with high purity, and 3) in a very short synthesis time (typically 10-30 mins). Three-dimensional (3D) (e.g. MAPbI3 and FAPbI3), bidimensional (2D) (e.g. Gua2PbI4) and one-dimensional (1D) perovskites (e.g. GuaPbI3) were reported, indicating also a unique flexibility of the mechanochemical step to provide access to different types of structures (Figure 1).

 

Figure1.gif

    Figure 1: Source http://onlinelibrary.wiley.com/doi/10.1002/anie.201607397/full 

 

Mixed spinel inorganic materials (e.g. MgFe2O4 and MgAl2O4 can be also synthesized in high yields, purity and short times of syntheses (15-30 mins) under solventless mechanochemical conditions. The mechanochemical approach provides a simple and efficient alternative to conventional methods to prepare spinels which typically employ large quantities of solvents (sol-gel, hydrothermal methods) or extremely high temperatures >1200ºC (combustion methods), illustrating the potential of this methodology. In addition to the green credentials of mechanochemistry, spinel materials obtained by this method were reported to be highly crystalline, homogeneous in shape and particle size and could be again obtained in large quantities (multi-gram scale) within a short processing time.

 

Similarly, metal-organic frameworks (MOFs) comprising organic molecules linking transition metals to form a porous material network have been also synthesized using solventless mechanochemical methods, providing access to new structures (e.g. pillared MOFS from their metal oxides, new porous MOFs or quasi-MOFs, etc.). Apart from the different new structures that can be potentially designed by means of the mechanochemical approach, the green chemistry advantages of the mechanochemical methodology are also clear: a 30 min grinding with limited quantities of solvents (via LAG) at room temperature could replace a 24-48 h solvothermal synthesis (100-160ºC) using large quantities of solvents and 10,000 times more energy consuming (http://onlinelibrary.wiley.com/wol1/doi/10.1002/anie.200906583/abstract)

 

Last, but not least importantly, bio(nano)conjugates have been recently developed using mechanochemical syntheses comprising redox proteins (e.g. horse hemoglobin) and magnetic nanoparticles for various relevant applications including the synthesis of carbon-based fluorescent polymers at room temperature (see Figure 2), electrochemistry and energy storage (http://pubs.rsc.org/en/content/articlelanding/2018/nr/c8nr00512e/unauth#!divAbst ract). In some cases, the utilized magnetic (and other non-magnetic systems) can also be effectively synthesized in a ball mill under mild reaction conditions (room temperature, solid-state reactions, solvent-free, typically in minutes).

Figure2.gif

 

Figure 2: Overview of the oxidative catalyzed polymerization of phenylenediamines.
Bottom images correspond to poly-o, m and pPDA (left image) and UV-irradiated poly-o, m and pPDA (365 nm), respectively. Source: http://pubs.rsc.org/-/content/articlehtml/2018/gc/c7gc03295a 
Reproduced by permission of the Royal Society of Chemistry

 

 

Mechanocatalysis

 

In addition to the mechanochemical syntheses, the possibility to conduct chemical reactions using mechanochemistry (mechanocatalysis) also recently emerged as a promising alternative to promote a number of chemistries under mild and environmentally friendly reaction conditions. Stemming from the aforementioned advantages, oxidations, C-C coupling reactions, acid-based catalyzed processes (e.g. esterifications) and related others have been already reported to take place under mechanochemical conditions.

 

Figure3.png

Figure 3: Mechanochemical/catalytic reactions: from reactants to products. Reproduced by permission of the Royal Society of Chemistry

 

 

 

 

Interestingly, biomass conversion was also successfully accomplished using mechanocatalysis, with examples of cellulose depolymerization to sugars and lignin deconstruction to valuable aromatics. This has a significant potential for further studies and its combination with a rational understanding of catalyst/process design will undoubtedly lead to important scientific advances in biomass conversion in future years.

 

Conclusions

 

From the beginning, this contribution has been aimed to provide an overview of the relevance and inherent advantages of mechanochemistry for multiple applications (materials design, catalysis, organic syntheses, biomass deconstruction, etc.). Reported results to date clearly illustrate the present and future potential and possibilities of mechanochemistry despite the relatively poor understanding of the phenomenon as such. Further studies are needed to be able to fully understand chemical, physical and structural changes taking place in mechanochemical syntheses (in-situ methodologies) to rationally design processes and methodologies based on such fundamental understanding. These studies will in any case complement nicely the burgeoning possibilities of mechanochemistry in various fields based on its inherent green credentials.

The non-agrarian among us may not know this, but petroleum-derived, non-biodegradable, effectively non-recyclable plastic mulch is used extensively in farms across America to control weeds, retain moisture in the soil, and increase crop yields.

 

My own experience with plastic mulch dates from 2002 when I worked on an herbicide/pesticide-free vegetable farm in northern Virginia. One of the techniques we employed to control weeds was laying down plastic mulch films about 4 feet wide tucked into the soil on both sides to form a bed in long rows up and down the fields. We transplanted acres of tomatoes, peppers, eggplant—you name it—into the beds with a tractor-pulled device that punched holes in the plastic, delivered fertilized water into those holes, and carried two workers low to the ground who could plant trays of transplants in rapid succession. It was quite effective and saved us a world of weeding later in the year. On the downside, at the end of the year, or end of the planting, we had to manually remove the now-dead vegetable plants that had grown on top of the plastic, pull up the plastic by hand, ball it up and take it to the landfill. Not particularly sustainable but if you ever have had to hoe all day in the humid hot Virginia summer—definitely worth it.

 

Now a Tennessee company, Grow Bioplastics, is working to create an alternative plastic mulch with a greatly improved sustainability profile. Essentially, they are seeking to use lignin, a waste product from the paper and biofuels industries, to create a biodegradable plastic mulch that farmers could literally plow into their fields at the end of the year—saving time and reducing waste.

 

In January, Grow Bioplastics received a National Science Foundation Small Business Innovation Research (SBIR) grant for $225,000 to conduct research and development work on Lignin-Biomass Based Biodegradable Plastics for Agricultural Applications.

 

“The National Science Foundation supports small businesses with the most innovative, cutting-edge ideas that have the potential to become great commercial successes and make huge societal impacts,” said Barry Johnson, director of the NSF’s Division of Industrial Innovation and Partnerships.

 

“Being selected for this competitive award from the NSF is a huge step for our company,” said Tony Bova, CEO and co-founder of Grow Bioplastics.

 

Bova and his co-founder Jeff Beegle are graduates of the University of Tennessee, Knoxville and started their company in 2016. They participated in the ACS Green Chemistry Institute’s Business Plan Competition held at the 2016 Green Chemistry & Engineering Conference and won.

 

“Winning the 2016 ACS Green Chemistry Business Plan Competition had a huge impact on our business, and we wouldn't be where we are today without that experience and funding,” says Tony Bova.

 

Grow Bioplastics is planning to launch their first products in 2019 which will be plastic pellets that can be processed into blown or cast plastic mulch films and thermoformed or injection molded trays and pots for agricultural and horticultural applications. With the SBIR money, they will be able to hire their first employee and will be collaborating with Glucan Biorenewables, LLC, to use their novel gamma-valerolactone derived lignin streams, and with Dr. David Harper, associate professor at the University of Tennessee Center for Renewable Carbon, to help evaluate the ability of their materials to be processed.

 

The Phase I NSF SBIR grant also opens up the opportunity to apply for a Phase II grant (up to $750,000). Small businesses with Phase II grants are eligible to receive up to $500,000 in additional matching funds with qualifying third-party investment or sales.

 

Bova-Beegle.jpg

Tony Bova (L) and Jeff Beegle (R), Co-Founders of Grow Bioplastics, with a sample of their lignin-based plastic.

Photo Credit: Adam Brimer/The University of Tennessee

 

 

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The Advanced Bioeconomy Leadership Conference on Development & Deployment (ABLC) is next week, February 28-March 2, 2018 in Washington, DC. The ACS Green Chemistry Institute’s Biochemical Technology Leadership Roundtable launched at this event in 2016, and this year they are back to present a two-part symposium on new high performance chemical intermediates and new pathways to current platform chemicals.

 

The first part of the symposium will be on the topic of “New High-Performance Chemical Intermediates”. This symposium will highlight the opportunities and challenges of commercializing new platform chemicals.  Renewable feedstocks can be a rich source of novel molecules that can serve as alternative building blocks in the synthesis of intermediates currently relying on petrochemical supply chains.  Individual speakers and a panel discussion will address the potential benefits of such molecules as well as the technical, economic, and market challenges along the way to commercialization.  Featured speakers are Peter Kneeling, CBIRC; Darcy Prather, Kalion; Kim Raiford, Origin Materials; Stephen Croskrey, Danimer; and  David Constable, ACS GCI.

 

The second part of the symposium will be about “New Pathways to Current Platform Chemicals”. In this symposium, the production of current, high-volume platform chemicals from alternative, low-carbon feedstocks will be discussed. New conversion technologies have opened up a variety of waste resources for making chemical intermediates currently derived from petroleum. Such “drop-in” molecules have the potential to displace fossil resources in chemical manufacturing without impacting current production routes. The speakers will provide examples of new pathways, discussing both the benefits and the challenges of bringing such products to market. Featured speakers are Bryan Tracy, White Dog Labs; Laurel Harmon, LanzaTech; Terry Papoutsakis, University of Delaware; Greg Smith, Croda; and Barbara Bramble, NWF (panel moderator).

 

Find out more: http://biofuelsdigest.com/ablc/

 

 

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Contributed by Abigail Giarrosso, Research Assistant at the Toxics Use Reduction Institute

 

As a sophomore chemistry major at the University of Massachusetts, Lowell (UMass Lowell), it was my time to take the chemistry major-specific organic laboratory course, a difficult and rigorous class. At the same time, I was working as a lab assistant at the Toxics Use Reduction Institute (TURI) where I was learning about green chemistry and working on replacing the solvent methylene chloride in commercial paint strippers. As I learned more about green chemistry through my time at TURI, I became very interested in being involved in the green chemistry community. As a result, I went to the Green Chemistry and Commerce Council (GC3) conference and I joined the nonprofit Beyond Benign. I learned about green chemistry from every source except my own university. I wanted to learn formally in class about green chemistry techniques and sustainable chemistry, but no courses were offered. As I thought back to my organic laboratory experience, I realized it would be a perfect opportunity to learn about waste reduction and using safer chemicals in hands-on lessons. I knew from my experience with the green chemistry community that places such as Gordon College had completely integrated green chemistry into their organic curriculum and so I was confident that finding safer experiments was feasible. I realized that this was an opportunity for awareness of sustainability and green chemistry to be formally taught at my school, making it easier for the next student to be informed and increasing awareness for future chemists.

 

I approached Dr. Jessica Garcia, the director of the undergraduate organic labs at UMass Lowell, and asked how she would feel if I tried to substitute some of the experiments for Organic Lab II with peer-reviewed, safer experiments. She was very enthusiastic about the idea because she was trying to do the same thing. So that is how came to take on helping “green” the organic labs as my senior thesis.

 

The project started in Spring 2016 with an initially straight-forward search to find safer replacements for the more complicated reactions. I found peer-reviewed articles on the Greener Education Materials for Chemists (GEMS) website on Diels-Alder, Wittig, and Michael and Aldol addition reactions. I also proposed that the experiments be conducted in microscale instead of miniscale to reduce the amount of waste generated. The highlight of the project was when I formally introducing green chemistry in class to the sophomore chemistry majors; covering what is green chemistry, why it should be important to them, and comparing and contrasting the previous and the new experiment in terms of safety.

 

Giarrosso.jpg

 

#1: Replacing a Diels-Alder Reaction

 

The first experiment that we replaced was the Diels-Alder reaction from the textbook Gilbert and Martin, which creates the byproduct sulfur dioxide and utilizes the solvents xylenes and petroleum ether.1 The safer experiment that I found in a different textbook was atom economic, created no byproducts, and eliminated the use of harmful solvents by using water.2 Both experiments involved heating under reflux, but the green experiment refluxed for three times as long as the original experiment. The students seemed to understand the safety improvements of the experiment but complained about the experiment being boring due to the long reflux. The substitution was successful and demonstrated the green principles clearly.

 

#2: Replacing a Wittig Experiment

 

Two different Wittig reactions were chosen to replace the original Wittig experiment. The original experiment, again from the Gilbert and Martin textbook, involved a very hazardous Wittig reagent benzyltriphenylphosphonium chloride, used dichloromethane (methylene chloride!), and concentrated sodium hydroxide.3 Two greener experiments were chosen to demonstrate the concepts of stereospecificity and isomerization. Both are considered solvent-less reactions and use safer Wittig reagents, and only took about 15 minutes to complete each one.4 The only issue I had with this experiment was that it needed hexanes to triturate the product. I tried substituting hexanes with undecane (heptane was not available) and successfully removed the product, but the boiling point of undecane was too high to isolate the product with adequate purity. The students struggled to perform two experiments simultaneously and struggled with the small amount of product produced at microscale. Since the minor isomer of the reaction with benzaldehyde was not detectable with a 60 MHz NMR the experiment will be discontinued. The stereospecificity reaction with 9-anthraldehyde will be kept on the curriculum for the next year.

 

#3: Replacing a Michael and Aldol Addition

 

The replacement of the Michael and Aldol addition was not as successful as the previous two experiments. The original experiment was a good candidate for replacement because of its hazardous starting materials and it uses toluene as a solvent.5 The safer experiment was a solvent-less experiment that used safer reactants and eliminated the use of toluene. The experiment involved mixing the reactants together, which made a liquid, and grinding them with a mortar and pestle until a solid formed and then refluxing the solid to get the product. Sadly, as hard as I tried, I couldn’t get my reactants into a solid. It became a very sticky paste, but not as the solid should have looked as described in the journal article. When I refluxed the paste, it did not result in the expected product. The students had a very similar experience to mine and the lab period consisted of 20 people furiously grinding paste. It was a good demonstration of how real research sometimes fails, but it was not a successful example of green chemistry.

 

Creating a New Organic Lab Experiment for Non-Majors

 

The second semester of my senior project Dr. Garcia and I wanted to create a new reaction that could introduce green chemistry in Organic I lab to other majors such as biology and chemical engineering that do not take the Organic II lab for chemistry majors. One experiment that could be replaced was the E1 dehydration of 4-methylcyclohexanol. The issues with this experiment was that the reactant and products had minor health issues and the reaction used concentrated sulfuric and phosphoric acids. The driving force behind replacing this experiment was that the product has a strong, unpleasant odor. Our goal became to create a new E1 reaction that had a more pleasant odor and utilized reusable acid catalysts to replace the use of concentrated acids. Dr. Garcia came across the journal article “Unsaturated Hydrocarbons with Fruity and Floral Odors” whose structures could theoretically be made through an E1 dehydration and were known to have a pleasing smell.7 The simplest molecule in the paper was butylidenecyclohexane which was a possible dehydration product of 1-cyclohexyl-1-butanol or 1-n-butylcyclohexanol. We decided to see if the alcohols could be dehydrated using the standard concentrated acids, reusable K10 montmorillonite clay, and reusable amberlyst catalyst. The products were analyzed by gas chromatography, NMR spectroscopy, and IR spectroscopy.

 

It was found that all three proton sources did dehydrate both alcohols resulting in varying ratios of products since the E1 dehydration results in multiple products due to carbocation rearrangement. The concentrated acids produced two products, including butylidenecyclohexane. While the reusable catalysts had about four different products, including the desired product. Sadly, through the synthesis of standards and dehydration of the alcohols, it was found that the new reaction did not have a strong fruity and floral odor and had more of a gasoline smell. Although one of the product standards created by Wittig reaction had a wonderful fruity smell, it was never the dominant product of the dehydration. Due to the cost of the starting alcohols and the lack of improvement of the smell of the experiment, the new reaction will not be implemented in the Organic I Lab curriculum. It was found that the original dehydration of 4-methylcyclohexanol works with the reusable K10 montmorillonite clay, creating an opportunity to introduce green chemistry earlier in the undergraduate academic career. Other E1 dehydration reactions are still being investigated for a new experiment.

 

Overall, I am very proud to have brought an aspect of green chemistry to my school and I hope it will inspire other faculty members to look at their own teaching lab experiments to reduce waste and hazardous materials. Although I am graduating, Dr. Garcia is looking for other students who are interested in creating new, safer experiments for the UML teaching lab.

 

References

  1. Gilbert and Martin. Experimental Organic Chemistry: a miniscale and microscale approach, 5th edition, 261-268.
  2. Pavia, D.L.; et al. A Small Scale Approach to Organic Laboratory Techniques, 3rd edition, 400-411.
  3. Gilbert and Martin. Experimental Organic Chemistry: a miniscale and microscale approach, 5th edition, 421-426.
  4. Nguyen, K. C.; Weizman, H. Greening Wittig Reactions: Solvent-Free Synthesis of Ethyl trans-Cinnamate and trans-3-(9-Anthryl)-2-Propenoic Acid Ethyl Ester. J. Chem. Educ., 2007, 84 (1), 119-121.
  5. Gilbert and Martin. Experimental Organic Chemistry: a miniscale and microscale approach, 5th edition, 625-630.
  6. Pavia, D.L.; et al. A Small Scale Approach to Organic Laboratory Techniques, 3rd edition, 324-326.
  7. Anselmi, C.; et al. Unsaturated Hydrocarbons with Fruity and Floral Odors. J. Agric. Food. Chem., 2000, 48, 1285-1289.

 

 

“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.

 

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Ken-picture.jpg

Contributed by Mary M. Kirchhoff, Ph.D., Director, ACS Green Chemistry Institute®; Executive Vice President of Scientific Advancement, ACS

 

The green chemistry community lost a friend with the passing of Ken Seddon on January 21.  Ken's stellar science, coupled with his strong opinions and kind heart, made him unforgettable (as did those muttonchops!)

 

I first met Ken in 1999 at the Green Chemistry Gordon Research Conference in Oxford. I knew Ken by reputation but did not meet him until I was waiting for a taxi at the Oxford train station. I noticed Ken's luggage tag, and exclaimed, “You're Ken Seddon!” He acknowledged the veracity of my statement and we agreed to share a ride to campus. When the cab pulled up, the driver began loading passengers from the rear of the line.  In a classic Ken maneuver, he slammed his hands on the bonnet of the car and shouted, "The front of the queue is over here!" The taxi driver quickly realized the error of his ways.

 

Ken could be intimidating; when I told him that I was glad to be on his good side, he replied, "No one wants to be on my bad side!" He was a wonderful listener and provided me (and many others) with comfort, support, and words of wisdom during difficult times. He told me on more than one occasion that he had the soggiest shoulder in Belfast.

 

I had the gift of a five-day visit with Ken in December. Ken continued to direct his research group at the Queen's University Ionic Liquids Laboratories, write manuscripts, and prepare proposals from the nursing home in Cultra. We had lengthy conversations about the future of green chemistry; not surprisingly, Ken assigned me a few tasks to do when I returned home. We talked about books, music, and movies, and Ken introduced me to the brilliant BBC show W1A.

 

Ken will be remembered for his groundbreaking research on ionic liquids, which earned him many accolades, including the Order of the British Empire (OBE) in 2015. What I will remember most about Ken was his warmth and kindness. He was a wonderful son to his lovely Mum Muriel, and a true friend to numerous colleagues around the world.  Ken's science will live on through the work of his many collaborators, and his generosity of spirit will live on in our hearts.

 

 

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The Franklin Institute in Philadelphia, Pa. has announced it is seeking nominations for the 2019 Bower Award and Prize for Achievement in Science of individuals who have made significant contributions to green and sustainable chemistry. The prizewinner will receive $250,000. Nominations are due May 31, 2018.

 

Bower-Medal-185.jpgThe Achievement in Science award was established in 1990 through the bequest of a chemical manufacturer and philanthropist Henry Bower. Each year a topic is selected for the award and this is the first time that the Institute has chosen Green and Sustainable Chemistry.

 

The Franklin Institute has been recognizing scientists, inventors and leaders since its foundation in 1824. Each year it gives out Benjamin Franklin Medals for chemistry, computer and cognitive science, earth and environmental science, electrical engineering, life science, mechanical engineering, and physics. The Achievement in Science Award is a relatively new addition to this program and rotates through these same seven topics—touching on the field of chemistry once every seven years.

 

“The Institute felt that Green and Sustainable Chemistry is a theme that is timely, relevant, exciting and robust, and now would be a great time to recognize that area,” says Beth Scheraga, director of the awards program at the Franklin Institute.

 

The awards committee has suggested subtopics for the nominations, although nominations are welcome in other areas of green chemistry as well.

 

  • New chemical processes with reduced hazardous byproducts
  • Applications of supercritical fluids in chemical processes as environmentally benign solvents for chemical reactions, extractions, and chemical analyses
  • Utilization of ionic liquids as environmentally friendly alternatives to volatile and flammable solvents in chemical processes
  • Use of catalysts that make chemical processes more selective, less energy intensive, or more economical in their use of feedstock

 

For more information, please see: https://www.fi.edu/bower-award-prize-achievement-science

 

 

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Contributed by Jane Murray, Ph.D., Global Head of Green Chemistry, Merck KGaA, Darmstadt, Germany (MilliporeSigma)

 

Summary

 

Increasing the availability of safer, sustainable solvents is expected to significantly impact industrial Green Chemistry programs. Cyrene™ [(-)-Dihydrolevoglucosenone] is a safer, bio-based alternative to petroleum-derived DMF (Dimethylformamide) and NMP (N-Methyl-2-pyrrolidone)1. Despite only recently becoming available in the quantities required for solvent usage, Cyrene™ has been successfully employed as a greener substitute in a number of industrially relevant applications, including graphene synthesis2 and carbon cross-coupling reactions3,4.

                               

Introduction

 

Fossil-derived solvents often constitute the bulk of a reaction or formulation; sustainable and safer alternatives are sought in order to address environmental, health and safety concerns, in addition to increasing regulatory restrictions. Recent attention has focussed on finding alternatives to dipolar aprotic solvents, DMF and NMP, due to increasing regulatory limitations resulting from their associated reproductive toxicity. Both the aforementioned solvents were recently added to the European Chemical Agency’s (ECHA) candidate list of Substances of Very High Concern (SVHC) for Authorisation.                       

 

Cyrene™ was developed by Circa Group in partnership with Professor James Clark, Ph.D., at the University of York’s Green Chemistry Centre of Excellence (GCCE)1. Its multifunctional fused ring structure affords a polarity similar to NMP without the inclusion of the amide functionality that is associated with the reproductive toxicity of NMP and DMF.  It is produced in only two steps from non-food cellulose, via a manufacturing process that is almost energy neutral and releases water to the environment. Cyrene™ has a density of 1.25g/mL and does not contain any chlorine, sulfur or nitrogen heteroatoms, which can present end-of-life pollution issues and create corrosive by-products if incinerated. It also has very low acute (LD50) and aquatic (EC50) toxicities that are well above the hazard thresholds defined by the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). Additionally, Cyrene™ is biodegradable and safer to handle than many oxygenated solvents due to its flash point of 108°C. It is stable to oxidation and (at end-of-life) upon incineration or biodegradation yields only carbon dioxide and water.

cyrene-molecules.jpg

Material Science Applications 

 

Graphene is a disruptive technology with potential applications spanning sustainable energy, biomedical, apparel and electronics. Despite its promise, commercialization is currently limited due to the challenges of manufacturing at scale. The common production method utilizing liquid exfoliation of graphite often results in low concentrations and employs NMP. Clark et al found that Graphene dispersions, obtained when NMP was substituted with Cyrene™, were an order of magnitude more concentrated2. The superior performance was attributed to the green solvent’s optimum polarity and high viscosity resulting in the creation of larger and less defective graphene flakes. This is anticipated to support graphene production at scale and contribute towards this revolutionary material realizing its commercial potential.

 

Interestingly, Katz et al. demonstrated that Cyrene™ could also be successfully employed as an alternative to DMF in the synthesis of metal-organic frameworks5.

 

Medicinal Chemistry Applications

 

Cross-coupling reactions are amongst the most utilized in the Pharmaceutical and Agrochemical industries, yet often employ DMF as their reaction medium. Switching to alternative solvents may necessitate increased reaction times, higher temperatures or the introduction of non-commercial catalysts. In partnership with Allan Watson, Ph.D., from the University of St Andrews, we developed a mild and robust method for the Sonogashira reaction employing Cyrene™ (Scheme 1)3. The greener alternative also enabled the cascade synthesis of functionalized indoles and benzofurans via a Cacchi-type annulation. The limitations of employing Cyrene™ as a solvent were also investigated. It was found that organic bases, including NEt3 and DIPEA, were tolerated at 50 C; however, the inorganic bases tested, with the exception of KOAc, were found to react with the solvent.

 

Scheme-1.png

     Scheme 1

 

A mild method was also developed for the Suzuki-Miyaura coupling reaction, employing Cyrene™ as a direct alternative to conventional solvents (DMF, THF and 1,4-dioxane) (Scheme 2)4. Excellent generality and functional group tolerance with high yields were obtained on both small and larger scale synthesis.

 

 

Scheme-2.png

     Scheme 2

 

Camp et al. employed Cyrene™ to develop a highly efficient, waste-minimizing method for the synthesis of ureas from isocyanates and secondary amines (Scheme 3)6. Notably, their method established a simple work-up procedure: The addition of water to the reaction solution resulted in precipitation of the desired urea. Filtration and washing with water yielded an analytically pure product. Their protocol led to a 28-fold increase in molar efficiency versus industrial standard protocols.

 

Scheme-3.png

     Scheme 3

 

Researchers continue to discover new applications for this greener solvent alternative. Cyrene™ was recently awarded Bio-based World News’ European Bio-based Innovation Award—a success that was attributed to it demonstrating that safer greener alternatives may also offer superior performance.

 

Cyrene™ is commercially available from Merck KGaA, Darmstadt, Germany (MilliporeSigma).

 

References

  1. Sherwood, J.; De bruyn, M; Constantinou, A.; Moity, L.; McElroy, C. R; Farmer, T. J; Duncan, T.; Raverty, W.; Hunt, A. J.; Clark, J. H. Chem Commun., 2014, 50, 9650 DOI: 10.1039/c4cc04133j
  2. Salavagione, H. J.;  Sherwood, J.;  De Bruyn, M.; Budarin, V. L.; Ellis, G. J.; Clark, J. H.; Shuttleworth, P. S. Green Chem. 2017, 19, 2550-2560 DOI: 10.1039/C7GC00112F
  3. Wilson, K. L.; Kennedy A. R.; Murray J.; Greatrex, B.; Jamieson, C.; Watson, A. J. B.; Beilstein J. Org. Chem. 2016, 12, 2005–2011 DOI:10.3762/bjoc.12.187
  4. Wilson, K. L;  Murray, J.; Jamieson, C.; Watson, A. Synlett, 2017, 28, A-E DOI: 10.1055/s-0036-1589143
  5. Zhang, J.; White, G.; Ryan, M.; Hunt, A. J.; Katz, M. ACS Sustainable Chem. Eng., 2016, 2, 7186-7192  DOI: 10.1021/acssuschemeng.6b02115
  6. Mistry, L.; Mapesa, K.; Bousfield, T. W.; Camp, J. E. Green Chem., 2017, 19, 2123 DOI: 10.1039/C7GC00908A

 

 

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