Project Details Metrics for Green Syntheses

Project No.:
Start Date:
01 October 2017
End Date:
Division Name:
Interdivisional Committee on Green Chemistry for Sustainable Development (ICGCSD)
Division No.:


To develop Green metrics and harmonize the correct application of green metrics analysis in syntheses.

The outstanding outcomes in the field of metrics will be such that once the guidelines and the protocol are sanctioned by a well-known and respectable body of scientists working under the IUPAC umbrella, chemists will be encouraged to submit procedures and experimental protocols following such well-defined guidelines and goals.


Green metrics is a relatively new concept in Green Chemistry since its founding 25 years ago. There is a general desire and fashion for chemists to be green given modern global concerns of climate change and resource scarcity, but there is a confusing multitude of meanings and approaches in the world-wide scientific literature to green metrics issues both in organic and inorganic chemistry.

Many of the reported experimental procedures in scientific journals that claim to be “green”, are in fact not when a careful metrics analysis is applied. The fact that these are nevertheless published shows the interest of publishers on the topic of “green” for its current and future importance. However, the current state of casual reporting of greenness based on one or two criteria and the general multitude of metrics available often with different names given by their author creators, yet having the same meanings, presents a bewildering and unscientific scenario, particularly for chemists who genuinely are interested in learning about, practicing and implementing green chemistry principles in their research work.

For these reasons, IUPAC must take the initiative and furnish its crucial support to regulate this pivotal field for chemistry in order to avoid the creation of misconceptions, fallacies, and abusive advertisements of “greenness” that threaten to discredit this important field of chemistry.

What we currently need is to set aside priority pretensions and personal expectations from so-called “green or sustainable chemistry”, advertised citations of authors’ publications in the scientific literature, and go beyond making fashionable, yet unsubstantiated, “green claims”. Therefore, green metrics are a necessary tool, as they serve to quantify in an unbiased way the efficiency or environmental performance of chemical processes, and allow practical and effective changes in chemical manufacture to be measured moving forward from rough and casual estimation to precision and accuracy. They are the basis of clear, rational, and directed optimization of reaction and synthesis performance. The field of green chemistry, by its very nature, is a comparative science which gauges the material, energy, environmental impact, and safety-hazard impact performance of any given new procedure to a given target chemical with all prior experimental procedures to that compound. A verifiable and credible claim of greenness of any procedure is therefore one that is not absolute, but rather is one that is comparable by metrics analysis to all prior procedures. This necessarily means that metrics analysis applied on a set of synthesis plans leads to their ranking. A true claim of greenness for a procedure means it scores high in all four categories of efficiency criteria: material consumption, energy consumption, environmental impact, and safety-hazard impact. In reality, since chemistry is a science of compromise, only a subset of these is achievable. Moreover, all optimizations are continuously ongoing as the task of improvement to the ideal goal is an evolutionary process and depends on the discovery of new reactions (e.g., multi-component, catalytic, etc.) and new methodologies to carry out existing reactions (e.g., continuous flow, microwave, etc.). Any claim of greenness must therefore be couched in the language of metrics analysis.

One of the fields which deserves attention and is not satisfactorily covered by publications is organic synthesis in connection with environmental protection and sustainability. We mean new reaction pathways and organic and inorganic catalysts involving and including fundamental chemistry, onto which any future development of green chemistry must accept to confront, as it is a real modem scientific challenge. It is necessary to give precise guidelines on synthetic green metrics to avoid misunderstanding and pretentious claims, due to subjective rather than objective evaluations.
The application of rigorous green metrics goes along with the experimental validation of synthetic procedures: experimental outcomes not only need to be reproducible in laboratory, but they also need to be evaluated by accurate metrics.
The motivation for using metrics is the expectation that by quantifying technical and environmental improvements, the benefits of new technologies will become more tangible, perceptible, or understandable by general public. This, in turn, would help the communication of research and facilitate the wider adoption of green chemistry technologies in industry. In fact, there is an expressed need and desire by both academia and industry to incorporate metrics analysis as a means to rigorously define efficiency and sustainability of chemical synthesis.
A genuine scientific journal is not yet available in this field; hence, this is the opportune moment to make a differentiation since most of the existing journals dedicated to green/sustainable chemistry deal with too vague topics in a very general way without giving the guarantee of a rigorous proof of “greenness”. This is particularly relevant with respect to Green Chemistry where an ethical requirement is associated with scientific rigor.


This project will focus on developing a survey, that is, a comprehensive compilation and ranking of available metrics that are currently used to gauge material, energy, and environmental impact metrics performances for individual reactions and synthesis plans. It is the first phase, and preparatory and compulsory for a follow-up project that will result with set of guidelines dealing with metrics limitations and guidelines for publishing result.

Feb 2018 update – project announcement published in Chem Int Jan 2018, p. 31;; see also published in that CI issue, a feature titled Green Green for Sustainable Development, by P. Tundo (ICGCSD chair) and E. Griguol

Dec 2019 update – The task group met and completed the review of a comprehensive compilation and ranking of available metrics. Next, a report is being prepared for publication in PAC.

Page last updated 5 Dec 2019