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We were thrilled to kick off the recent Green Chemistry and Engineering Conference (GC&E) with a keynote from Professor Helen Sneddon about the importance of green chemistry. Sneddon is a professor of sustainable chemistry and the director of the Green Chemistry Centre of Excellence at the University of York — a premier international academic center dedicated to advancing green and sustainable innovation processes and products. She is also a member of the Royal Society of Chemistry’s Green Chemistry Journal and has a rich background in green chemistry in the pharmaceutical industry.
In her keynote, “Green chemistry … essential for academia and industry,” Sneddon highlighted four themes that are integral to developing a circular economy: renewable feedstocks, green synthesis, sustainable technologies, and design for reuse, degradation, and recovery. Continue reading for highlights from her talk.
Renewable Feedstocks
By 2050, various aspects of the world we know now will change considerably. The world population is projected to reach 9.8 billion by 2050, according to the United Nations (UN), and the economy is predicted to more than double in that time.
“Despite seeing business as usual continuing in many spheres, there's a growing recognition that we're going to have to change,” Sneddon said. “There are laudable targets around how we have to change.”
The drive to use renewable resources addresses a number of the UN’s 17 Sustainable Development Goals (SDGs), Sneddon said. “It's critical to affordable and clean energy. It also ties into zero hunger,” she says. “We can't afford to be turning farmland for food crops over to growing crops for energy. And it's also an essential part of responsible consumption and production.”
One innovative example of utilizing food byproducts as a feedstock can be seen through research conducted by Sneddon’s colleagues at the University of York. Citrus peels collected from orange juice factories can be an important source of pectin and other valuable materials, and aspects of this project have also been turned into useful teaching experiments. Mindful of the increasing focus on sustainable protein sources, Sneddon also highlighted a collaboration between B-hive Innovations, a small company aiming to drive innovation in the fresh produce industry, and Branston, UK’s largest potato producer, to extract protein from potato waste. This project was one of the recent success stories to come out of the Biorenewables Development Centre at the University of York, a center formed from the GCCE and Centre for Novel Agricultural Products, which partners with small companies to help develop, scale up, and commercialize bio-based products and processes for the marketplace
The GCCE is also now proud to be part of the Supergen Bioenergy Hub, Sneddon said. “Mindful that bio-based energy must be considered as part of an interconnected system, we’re looking to contribute sustainable chemistry and technology to develop bio-derived and biodegradable materials,” she said. “We’re looking at bio-based materials, and we're working with industry and biology colleagues to understand how products that are intended to go down the drain or products that are spread on agricultural land will affect anaerobic digesters when they reach those either through the sewage systems or through biomass anaerobic digestion.”
“90% of reaction material is discarded.” Chart from Helen Sneddon’s keynote.
Green Synthesis
In addition to our starting materials, we need to be considering the nature of the chemistry we do and the reagents and conditions that we use as part of a move toward closing the loop and developing a circular economy. Drawing on her background in the pharmaceutical industry, Sneddon noted the process of creating an active pharmaceutical ingredient (API) can result in substantial waste in the form of solvents, wastewater, and other materials. Extrapolations from industry average data suggest more than 10 billion kilograms of waste is being produced annually, costing more than $20 billion for disposal, Sneddon said.
“Anything we can do to increase the likelihood of those early compounds in drug discovery being successful and to decrease the time taken to deliver a medicine is highly likely to be beneficial to the overall sustainability of this process, and indeed, its profitability. And in fact, more broadly, anything we can do to avoid wasted experiments across chemistry due to poor research design or poor research reporting, as well as duplication of efforts in replicating unpublished results, has to be beneficial,” Sneddon said, highlighting that green chemistry is fundamentally aligned with many other industry priorities.
In recent years, Sneddon has been involved in developing tools to help guide chemistry to make more sustainable choices. Among these tools are the GlaxoSmithKline (GSK) solvent sustainability guide, which gives ratings to commonly-used solvents to help chemists assess them, and the NMR guide, which seeks to remove one of the barriers to using new bio-derived greener solvents. Sneddon also highlighted the ACS GCI Pharmaceutical Roundtable’s Reagent Guides, which help chemists choose greener reaction conditions across a number of chemical transformations.
Photo by RHanush on Wikimedia Commons.
Sustainable Technologies
Clearly, alongside considering reagents and solvents, there are also opportunities to explore advantages offered by different technologies – which, depending on scale, may be significant.
“The GCCE has a long history of working with supercritical CO2, which can offer several advantages and extraction and purification. And we've got collaborations ongoing at the moment, looking at the extraction of oils from fibers and the extraction of flavor and fragrance compounds from food,” Sneddon said.
“We're open to exploring various technologies that could improve the overall sustainability of chemical reactions and chemical processing. We've dabbled in flow chemistry and mechanochemistry, for example. … And I'd even stretch this definition to include solid supported chemistry here,” she said.
The GCCE is building on work done by Professor Mike North and Dr. Anne Routledge, looking at the replacement of Dimethylformamide (DMF) by a mixture of ethyl acetate and either propylene carbonate or the GCCE discovered solvent 2,2,5,5- tetramethyl oxo... for solid phase peptide synthesis. Sneddon and Routledge will be working with a Ph.D. student to take the research further by looking at more atom-efficient amine protecting groups and more efficient peptide coupling protocols that would be compatible with benign solvent choices, Sneddon said.
Design for Reuse, Degradation, and Recovery
To complete the cycle, Sneddon discussed designing products with the impact of their end-of-life in mind. “Several of our projects are engaged with the end-of-life materials — this links back to biodegradability mentioned earlier. So we're mindful of the principles of benign by design,” Sneddon said. “We're seeking to avoid known current issues and avoid further inadvertent consequences from the processes and products that we're developing.”
While the GCCE is interested in designing future products more sustainably, the organization is aware of the legacy of products that were not designed with this in mind, Sneddon said.
“Over the years, the GCCE have had several projects based on the recovery of valuable and/or harmful components from the environment, including phytoremediation projects and projects where we've looked at the recovery of metals,” she said. One recent example was the Reclamation, Remanufacture of Lithium Ion Batteries (R2LIB) project, designed to recover polyvinylidene fluoride from lithium batteries, supporting the recycling of the technology.
“We're ideally designing products either to be easily recoverable and reusable or to safely biodegrade,” Sneddon said.