Jan 032012

While pursuing my Ph.D. project in chemistry, I am often confronted with a disturbing experience: Fellow scientists freely admit that the terminology they use when communicating their research to the public is dominated by catchy slogans. Moreover, these slogans often have not much in common with the research they pretend to explain. Even as a doctoral student, I sometimes find myself in the situation to present my work in terms of a distorting language. On the occasion of this year’s Falling Walls Conference, I want to share some thoughts on this style of speech that scientists often employ when addressing a broader audience. As the conference included a lecture by Paul Chirik entitled ”Breaking the Wall of Sustainable Chemistry. How Modern Alchemy Can Lead to Inexpensive and Clean Technology”, I will use the example of “sustainable” or “green” chemistry. These expressions have grown increasingly popular in public, but most scientists will agree with me when I claim that they confuse the public and do not enlighten it. In fact, expressions like “sustainable physics” or “sustainable biology” are by far not as popular as “sustainable chemistry”, which already hints at the latter being a conspicuous neologism.

Let us now look at the challenge of sustainability and chemistry’s role in this context. With global population having surpassed seven billion people in 2011, the importance of economic, environmental, and social sustainability at all levels of human society becomes more and more obvious. As chemical industry holds a central position in the world’s economy, one question naturally arises: How can industrial processes be designed in a sustainable manner? Important aspects related to this overriding question include the reduction of fossil fuel consumption, the minimization of waste production, and the replacement of toxic or expensive substances by harmless or inexpensive ones. The latter aspect was exemplified in Paul Chirik’s lecture, which dealt with attempts to replace the precious metal platinum by the cheap and abundant metal iron in chemical reactions. Without commenting on his lecture in detail here, my personal perception—and probably the interested layman’s perception, too—was that Paul Chirik convincingly showed how the replacement of platinum by iron is carried out in detail, i.e., what principles are applied, which hurdles have been overcome, and which problems remain to be solved.

The attentive reader may have noticed that I have not used the terms “sustainable chemistry” and “green chemistry” when presenting Paul Chirik’s lecture. Why? The reason is simple: I think they are unnecessary and, furthermore, possibly misleading. Let us examine the term “sustainability” in more detail. It can be vaguely defined as the capacity to endure, but its usage has become so popular and widespread that a comprehensive definition is beyond the scope of this essay. However, in the present context it is important to realize that sustainability originally referred to human agency and ethical standards. Accordingly, the word was used in philosophy, economics, and politics, or more general, when dealing with humans or the human society as a whole. As a consequence, the concept is inapplicable to natural science, which seeks to shed light on the principles that govern the natural world.

Now let us try to understand what sustainable chemistry really is. For the reason outlined above, I would not consider it as a new chemical branch comparable to inorganic chemistry, biochemistry, or analytical chemistry. Instead I claim that sustainable chemistry is a specific point of view from which one may reexamine established chemical methodology. This reexamination applies ecological and economic criteria to chemistry, thus a catchy definition of sustainable chemistry could be: Sustainable chemistry is the mere continuation of economics and ecology by chemical means. To underpin this claim, let us look at the twelve principles of green chemistry formulated by Anastas and Warner.[1] They are:

1. It is better to prevent waste than to treat or clean up waste after it is formed.

2. Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product.

3. Wherever practicable, synthetic methodologies should be designed to use and generate substances that possess little or no toxicity to human health and the environment.

4. Chemical products should be designed to preserve efficacy of function while reducing toxicity.

5. The use of auxiliary substances (e.g. solvents, separation agents, etc.) should be made unnecessary wherever possible and innocuous when used.

6. Energy requirements should be recognized for their environmental and economic impacts and should be minimized. Synthetic methods should be conducted at ambient temperature and pressure.

7. A raw material or feedstock should be renewable rather than depleting wherever technically and economically practicable.

8. Reduce derivatives – unnecessary derivatization (blocking group, protection/ deprotection, temporary modification) should be avoided whenever possible.

9. Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.

10. Chemical products should be designed so that at the end of their function they do not persist in the environment and break down into innocuous degradation products.

11. Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances.

12. Substances and the form of a substance used in a chemical process should be chosen to minimize potential for chemical accidents, including releases, explosions, and fires.

These principles do not constitute a set of strict rules but rather a guideline. While their detailed discussion would require another essay, I only point out here that they can all be considered applications of basic economic and ecological principles to chemistry. In my opinion, this claim holds true for all further ideas related to sustainable chemistry.

What should one think of this development? As far as I can see, some chemists fear that the original scientific principles of chemistry are in danger of being replaced by economic principles, yet I think this fear is absolutely groundless. The principles of economy and ecology will not replace established chemical methodology but they can and should drive chemical research. Since sustainable development is so crucial for our society, every scientist should have a basic knowledge of economy and ecology. On the other hand, the traditional chemical methodology is not outdated, but provides the means necessary to achieve an ecological goal. As Paul Chirik illustrated in his talk, the assessment of a certain industrial process with respect to sustainability is most often not straightforward, but rather complicated and requires an integrated approach taking into account countless details. The understanding of these details is the scientist’s intrinsic domain, yet to assess the impact of his research, the importance of a broader background comprising economic and ecological knowledge grows. Accordingly, my first conclusion is that sustainable chemistry is important and should be taught to chemistry students. However, it should not be presented as a chemical discipline, but as a valuable extension.
My second claim is that the public popularity of the term “sustainable chemistry” results from a worrisome confusion between chemistry and chemical industry. This confusion becomes entirely obvious when looking at the even more popular expression “green chemistry”. I am convinced that this expression derives its popularity from a seemingly inherent tension as many people equate green with clean and chemistry with dirty. Yet in reality, chemistry is neither dirty nor clean, but chemical industry can be dirty and we need to make it cleaner. In this context, expressions like “green chemistry” or “sustainable chemistry” are in danger of being abused as public relations label and of being perceived by the layman as chemical methodology. In this way, the confusion between chemistry and chemical industry is not resolved but even increased. To dispel public concerns about chemistry—or in FallingWalls language, to break the wall between chemistry and the public—one should make very clear that sustainability is an ethical concept—which chemists in industry and science ought to be aware of and which may drive chemical research—but not a scientific principle.
After all, there is a simple conclusion: It is every scientist’s duty to employ an understandable but still precise language. If we feel seduced to replace a lengthy and cumbersome explanation by a catchy one-liner, we should recall that this is easy in the short run, but feeds the public mistrust against science in the long run.

— Thomas Jagau

[1] P. T. Anastas and J. C. Warner, “Green Chemistry: Theory and Practice”, Oxford University Press, New York, 1998, p.30.

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