Comment
https://doi.org/10.1038/s41570-023-00523-9
Modern chemistry is rubbish
Hannah Flerlage & J. Chris Slootweg
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To combat worsening environmental crises,
chemistry needs a redesign. We see the need
for a triple focus on efficiency, safety and
circularity as a prerequisite for chemistry to
serve sustainability and ensure that essential
chemical products and processes are
waste-free, functional and safe for both
humans and the environment.
Focusing only on making new and exciting molecules and materials
does not do justice anymore to the chemistry discipline in our modern
world. It is even unethical to continue to develop chemistry that leads to
chemical pollution. Therefore, we should stop making poorly designed
compounds, in particular “forever chemicals”2 such as per- and polyfluorinated alkyl substances and brominated flame retardants, and focus
instead on the development of much more benign alternatives, including
the anticipation and avoidance of future problems by embracing sustainable design. This requires systems thinking, grounded in the recognition
of sustainability as an emergent property of a system, and should be
guided by an understanding of the molecular basis of sustainability6.
Climate change, energy crisis, resource scarcity, biodiversity collapse,
not to mention a global pandemic; you may rightfully conclude that
modern life is rubbish. In view of mounting environmental pollution
with waste chemicals and their impacts, from ozone depletion to biodiversity loss1, one might also say modern chemistry is rubbish. Since
the Industrial Revolution, we have adopted a strong habit of exploiting
finite resources and converting them into useful products following a
linear ‘take–make–dispose’ approach. Chemical manufacturing processes and technological advances have created ample chemical waste
both during and after production, which has resulted in human health
problems and environmental disasters at different scales2. Chemistry
is searching for creative, often complex, ways to facilitate the path of
matter from extraction to pollution in the form of chemicals. In this
sense, modern chemistry is, quite literally, rubbish. In the past 25 years,
however, the principles of green chemistry have spurred — in both academia and industry — the design of chemical products and processes
minimizing or even eliminating the use of hazardous substances and
waste3,4. More and more sustainable synthetic methods for the creation
of molecules and materials are nowadays available. But are we there
yet? Not at all!
“…it’s fun and rewarding
to create aesthetically
pleasing molecules, but
wouldn’t it be even more
exciting if these discoveries
served a purpose too?”
What a cool molecule
New discoveries and high-level publications are often celebrated with
posts on social media, eliciting responses such as “cool molecule”, and
“awesome chemistry”. And yet, while we continue to develop the current
state of the art and explore the boundaries of our science, shouldn’t we
also explicitly focus on highlighting the newly generated knowledge
and its potential societal impact? Yes, it’s fun and rewarding to create
aesthetically pleasing molecules, but wouldn’t it be even more exciting
if these discoveries served a purpose too? Chemical & Engineering News
readers’ favourite molecule of 2022 illustrates this nicely. Undoubtedly, the synthesis of the highly symmetrical perfluorocubane C8F8 is
a stellar achievement5, and its short-lived radical anion C8F8•– detected
by matrix-isolation electron spin resonance spectroscopy is intriguing. Potential future applications for the development of functional
materials were mentioned to highlight the importance of the discovery.
Yet, the structure of this cage compound with its multiple C–F bonds
suggests that it will, like other compounds of the type, persist in the
environment and bioaccumulate, and thus raise environmental problems, even if it is discovered to have particularly useful properties.
nature reviews chemistry
Chemistry needs a triple focus
Recent advances in chemical synthesis have frequently focused on
the use of renewable resources and reduced waste in production but
have done so without always considering their life-cycle environmental footprints and overall environmental implications7. Our focus on
optimizing the required resources for chemical production comes at
the expense of ignoring problems on the products side, which are often
much more severe. For example, making drop-in bio-based polyolefins,
such as bioPE —made from ethylene obtained by dehydration of
bioethanol — is not improving the recyclability or biodegradability
of the product, and thus continues to contribute to plastic pollution.
Likewise, it has become increasingly difficult to produce clean water
as classical wastewater treatment systems are not designed to handle contaminants of concern. More novel chemicals with diverse risk
potential and the increasing rate at which they are discovered means
that we exceed our ability to conduct safety-related assessments and
monitoring2. Chemistry is the science of the transformation of matter,
not just of the creation of novel molecules. So, how can we design and
develop safe chemistry that uses our resources most effectively
and improve sustainability?
To fully focus chemistry on sustainability, we see the need to apply
a triple focus (Fig. 1) to design both processes (synthesis) and products
(chemical structure) to be efficient, safe and circular. Chemistries and
chemicals must be efficient to reduce resource and energy inputs
and reduce the use of chemicals to the precise amount needed for its
function. Safe for both human health and in the natural environment,
preventing the generation of (eco)toxic, bioaccumulative, persistent
and mobile compounds, and reducing or eliminating the use and generation of hazardous substances in production processes. Circular to
mimic natural cycles and to design closed-loop systems to ensure the
Volume 7 | September 2023 | 593–594 | 593
Safety
Efficiency
Circularity
Sustainable
chemistry
Fig. 1 | The future of chemistry. A triple focus of efficiency, safety and circularity
is needed to steer chemistry towards sustainability.
recovery and recycling of valuable products and any wastes. These core
values, described by the green chemistry3, circular chemistry8, and safe
and sustainable-by-design9 paradigms, must be adhered to all at once
for chemistry to be able to contribute to sustainability.
The future of chemistry
We need to broaden our horizons and consider our chemistry beyond
the reaction vessel and the fume hood: how do the molecules and materials we make under very controlled conditions interact with the technosphere (industrial systems and society) and the biosphere (nature)?
Are chemical additives and products really essential in a particular
application? If they are, then they need to be benign. For example, for
plastics (and essential plastic additives), cycles must be designed
for recovery and recycling to enable closed-loop usage with efficient
processes. By contrast, products that are not suitable for recovery and
recycling as they end up in complex waste streams, such as pharmaceuticals, personal care and cleaning products, should be designed for
biodegradation, effectively mineralizing in the environment10. As such,
the elements are taken up by the respective biogeochemical cycles,
and the residence time of chemicals in the environment is reduced
along with risks of potential toxic effects.
Redesigning chemicals so that they present reduced environmental hazards makes chemistry more challenging (but also more
nature reviews chemistry
rewarding), not to mention multidisciplinary, as it requires us to fully
embrace circular design, life-cycle thinking, human and environmental
toxicology, and environmental and social impact assessment. Especially synthetic and environmental chemists, those who make chemicals and those who detect chemicals, must collaborate closely to bend
the linear path from extraction to pollution into safe cycles. Zero waste
and zero pollution should be the ultimate aim by (re)designing processes, chemicals, and products to keep materials in safe and efficient
closed loops while meeting our needs. There is a lot to learn for all of us.
We can and must create the material basis for a sustainable future, and
integrate functionality with efficiency, safety and circularity as early
as possible in the innovation process and throughout the life cycle in
order to realize this ambition.
Hannah Flerlage & J. Chris Slootweg
Van ’t Hoff Institute for Molecular Sciences, Research Priority Area
Sustainable Chemistry, University of Amsterdam, Amsterdam,
The Netherlands.
e-mail: j.c.slootweg@uva.nl
Published online: 31 July 2023
References
1.
Steffen, W. et al. Planetary boundaries: Guiding human development on a changing
planet. Science 347, 1259855 (2015).
2. Persson, L. et al. Outside the safe operating space of the planetary boundary for novel
entities. Environ. Sci. Technol. 56, 1510–1521 (2022).
3. Anastas, P. T. & Warner, J. C. (eds) Green Chemistry: Theory and Practice (Oxford Univ.
Press, 1998).
4. Krasnodębski, M. Lost green chemistries: history of forgotten environmental trajectories.
Centaurus 64, 509–536 (2022).
5. Sugiyama, M. et al. Electron in a cube: synthesis and characterization of perfluorocubane
as an electron acceptor. Science 377, 756–759 (2022).
6. Mahaffy, P. G., Matlin, S. A., Holme, T. A. & MacKellar, J. Systems thinking for education
about the molecular basis of sustainability. Nat. Sustain. 2, 362–370 (2019).
7. Galán-Martín, Á. et al. Sustainability footprints of a renewable carbon transition for the
petrochemical sector within planetary boundaries. One Earth 4, 565–583 (2021).
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Chem. 11, 190–195 (2019).
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and sustainability dimensions, aspects, methods, indicators, and tools (Publications
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10. Kümmerer, K., Clark, J. H. & Zuin, V. G. Rethinking chemistry for a circular economy.
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Competing interests
The authors declare no competing interests.
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