The Importance of Closing the Loop

[ACSGCI]

Contributed by Dr. David Constable, Science Director, ACS Green Chemistry Institute^®

Over the past five years or so there has been growing public awareness and increasing attention being paid to how society might move towards a Circular Economy. Organizations like the Ellen MacArthur Foundation have been at the center of this movement and have been advocating in a variety of areas, most notably thinking through Society’s unsustainable use of plastics and how to address what is now seen as a global blight of plastics in the oceans. If one begins to think deeply about the technical and economic issues surrounding any move towards a circular economy, it is readily apparent that there are a large number of major technical, behavioral, cultural, and economic hurdles to overcome. It is also apparent that looking at product development from a systems thinking, life cycle, and green and sustainable chemistry perspective can be very powerful, and this combination of analytical methodologies may help chemists and engineers to address many fundamental impediments to closing the loop.

That’s why this year’s 23^rd Annual Green Chemistry and Engineering Conference/9^th International Conference on Green and Sustainable Chemistry is devoted to how green chemistry and engineering are instrumental in moving towards Closing the Loop. With 42 different sessions, the Conference will be covering a wide array of topics that are relevant to Closing the Loop. There are, of course big challenges to closing the loop, and a few of these are discussed in seven different sessions that cover a variety of plastics issues (degradability, oceans, etc.), critical elements, and access to medicines. Chemists and chemical engineers know the critical part that catalysis plays in making chemistry more sustainable, so it is fitting that there are four sessions touching on biocatalysis, earth abundant metal catalysis, catalysts for CO₂ conversion, and catalysis that will enable the circular economy.

If the world needs to move towards a circular economy society will need to educate and train chemists and engineers to address the major unmet challenges of sustainability. There are five different sessions devoted to education, two of which are covering systems thinking. Systems thinking is a pivotal, fundamental skill scientists and engineers will need since closing the loop requires one to think across multiple systems and design chemicals, synthetic routes and processes in ways that minimize adverse systemic, life cycle impacts while maximizing sustainability outcomes.

Speaking of processes, there are six sessions related to different aspects of chemical processing. Process intensification and batch-to-continuous flow processes, especially in the batch chemical industry, are critically important avenues to decreasing the mass and energy intensity of chemical processing. An oft-forgotten consideration in green chemistry and engineering is large volume commodity manufacturing, and this year we are delighted to devote a session to how these industries can become more sustainable. Another usually forgotten unit operation in chemical processing responsible for 10- 15% of worldwide energy use is separations. A session will be exploring alternatives to distillation for organic solvent separations and separations of small molecules from dilute aqueous solutions.

The nature of chemical feedstocks needs to change if we are to close the loop, so there are four sessions related to alternative feedstocks. Clearly, we have a critical and continuously expanding need to use CO₂ as a feedstock. Besides CO₂, there is a need to see waste not as something to be burned or buried, but something that is a feedstock for chemical processes. In addition, we need to continue our evolution towards the use of biomass as a source of carbon and see the efficiency of bio-refineries rapidly increase to be equivalent to petrochemical feedstock conversion. These sessions will continue the discussion of these important areas of technical development.

Two other important conference session groupings are related to entrepreneurs and product development. Entrepreneurs are usually early adopters of new technologies and are responsible for commercializing many innovations deemed too risky by larger corporations. These sessions are intended to help entrepreneurs in start-ups to more efficiently commercialize their innovations. Product challenges, on the other hand, exist in companies both large and small. There are four sessions related to product challenges in textiles and electronics, with an additional session that breaks new ground with presentations on regenerative design in products. Finally, a product showcase will once again be part of the poster session and attendees will have the opportunity to see products that are being commercialized.

While there are many other sessions I’ve not described, I will end with three sessions related to the use of computers for toxicity prediction, in-silico design and artificial intelligence. In one way or another, all of us will be touched by the rapid development and implementation of AI/machine learning in discovery, process design and control, and product design. I am personally very excited to see these sessions as I strongly believe that chemistry is ripe for disruption through these technologies.

Regardless of which sessions you attend, I hope you are able to join us for what promises to be a most interesting and exciting conference!