“Happy silver anniversary”: Green Chemistry at 25

Paul Anastas a, Buxing Han b, Walter Leitner c and Martyn Poliakoff d
aYale University, Forestry & Environmental Studies, New Haven, Connecticut, USA. E-mail: paul.anastas@yale.edu
bInstitute of Chemistry, Chinese Academy of Sciences, , Beijing 100190, China. E-mail: hanbx@iccas.ac.cn
cInstitut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany. E-mail: leitner@itmc.rwth-aachen.de; Fax: (+49) 241-80-22177; Tel: (+49) 241-80-26481
dSchool of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK. E-mail: martyn.poliakoff@nottingham.ac.uk; Fax: (+44) 115 951 3058; Tel: (+44) 115 951 3520

2016 is the Silver Anniversary for the field of Green Chemistry. As we look back at 25 years since the term “Green Chemistry” was first coined and defined in 1991, it would be easy to reflect on all of the field's tremendous scientific accomplishments and business achievements and declare it “mature”. However, there is perhaps no more undesirable compliment a field can receive than to be deemed mature, and fortunately, calling the field of Green Chemistry mature would be profoundly incorrect. One could argue that over the past 25 years, Green Chemistry has just been warming up and is now ready for the continuing and ever more important race toward sustainability.

There is often a discussion about the relationship between the terms “Sustainability” and “Green Chemistry”. On many occasions, you may have been confronted with the argument that “it is not enough to be ‘Green’ – chemistry must be economically viable to be sustainable”. Yes and No! Of course, Sustainability is a wider concept than Green Chemistry – in fact it is a wider concept than any individual science or technology. And it is also true that not all research programmes in Green Chemistry will inevitably lead to more sustainable processes that will be implemented on an industrial scale. However, it is proven with countless examples that following the concept of Green Chemistry can and will lead to innovation that combines environmental benefits with economic profit and social welfare. Or in other words: if Sustainability is the goal, Green Chemistry will show the way!

Prior to the formal beginning of the field of Green Chemistry, there was a tremendous amount of activity aiming to improve chemistry in ways that would make it less detrimental to the environment. What happened in 1991 was perhaps nothing more or less than a crystallization and extension of these excellent and prescient efforts into a single definition and moniker.

The formulation of the “12 Principles” played a major role in the perception of Green Chemistry by the scientific community. The Principles are guidelines rather than rules, and serve as a motivation rather than restriction for fundamental science. Obviously, they do not provide a simple “check list”, where a chemical reaction or process will automatically get “greener” with the number of principles addressed in its development. The Principles were not conceived as problem-solvers, but they serve as tools for analyzing major potentials for environmental improvement of given value chains and for their translation into defined challenges for fundamental science.

If we look at the Twelve Principles of Green Chemistry as a structure at the time of their definition, one can see that atom economy and atom utilization had already been proposed in 1990, the efforts in biodegradability were well established, waste minimization or ‘clean’ reactions were discussed, utilization of renewable feedstocks had been in place for decades, catalysis for lower energy and selectivity was a perennial focus in industry and academia, and accident prevention through inherent safety had been well-recognized.

However, some areas covered by the 12 Principles that had not been well developed included full synthetic methods and pathways that were benign by design, molecular design for reduced toxicity, a rigorous attention to replacing hazardous solvents generally, and real-time in-process analyses. But perhaps more importantly, what had not previously been recognized is that one could view all of these elements as a system that could be mutually reinforcing and ideally synergistic. While trade-off between the Principles can and does happen when certain choices of methods are made, the trade-offs are not intrinsic and are a reflection of those choices – a matter of design. Design, perhaps the most important word in the definition of Green Chemistry, makes it clear that the consequences – all of the consequences – of our chemistry are not merely artifacts for which no one is responsible. Rather they are directly related to the design choices that we make thoughtfully or ignore at our peril. Design does not happen by accident, but rather is an indication of intention.

After 25 years, the 12 Principles are no longer perceived as a collection of elements, they have been transformed into a cohesive system. This shift in thinking has been accompanied by a transformation of Green Chemistry from a way of getting rid of bad things (inefficient syntheses, toxic reagents, needless waste, etc.) into an approach that is used as a way to generate better things (in essence a tool for innovation to generate new performance, function, and efficiencies). Accomplishments like these have been implemented in virtually every industrial sector ranging from energy to agriculture to materials to pharmaceuticals to personal care and beyond. With all of this well-established and well-documented, one would think that the field could look back and rest on its laurels, however, that runs totally counter to the character of the Green Chemistry community.

We have therefore asked colleagues from the Editorial and Advisory Board of this journal to comment on individual Principles that relate to their specific area of expertise and to share their personal views with our community. Each month of 2016 will see Green Chemistry feature one such perspective Editorial, hopefully initiating a lively exchange of views and ideas in a corresponding forum on the Green Chemistry blog (http://rsc.li/gc-25years-forum). The Editorials are not meant to provide answers, but to stimulate questions on how the Principles have influenced research agendas, how they connect to challenges and opportunities that may not have been visible twenty five years ago, why they are still valid or what needs to be adjusted, etc. Most importantly, the aim is to not primarily to look back in praise of the undisputable achievements, but to provide a vision towards celebrating the Golden Anniversary of the field in 2041 and beyond. The Editorials will be collated online as they are published and will be available to view here: http://rsc.li/gc-25years.

There are several definitions for the word “green” in the dictionary but perhaps the most relevant is “young, fresh, new”. As our field strives to remake our definitions of elegant chemistry, this perpetual quest should be enough to keep it evergreen.

This journal is © The Royal Society of Chemistry 2016