The 12 Principles of Green Chemistry

The 12 Principles of Green Chemistry (, first propounded by Anastas and Warner [1] are a widely accepted set of criteria for assessing the “greenness” or environmental acceptability of processes for the manufacture of chemical products

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 maximise 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 efficiency 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 recognised for their environmental and economic impacts and should be minimised. Synthetic methods should be conducted at ambient temperature and pressure.

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

8. Unnecessary derivatisation (blocking group, protection/deprotection, temporary modification of physical/chemical processes) 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 so as to minimise the potential for chemical accidents, including releases, explosions and fires.

Poliakoff and colleagues have reported [2] a mnemonic, PRODUCTIVELY, which captures the essence of the twelve principles of  green chemistry and can be shown on a single slide:

P – Prevent wastes

R – Renewable materials

O - Omit derivatization steps

D – Degradable chemical products

U – Use of safe synthetic methods

C – Catalytic reagents

T – Temperature, pressure ambient

I – In-process monitoring

V – Very few auxiliary substances

E – E-factor, maximize feed in product

L – low toxicity of chemical products

Y – Yes, it is safe

More recently, the concepts have been extended to the 12 Principles of Green Engineering [3] and a mnemonic, IMPROVEMENTS, to capture their essentials [4]. Catalysis is at the heart of many of these principles and plays a key role in developing green and sustainable technologies for chemicals manufacturte[5].

Leading References

1. P. T. Anastas and J. C. Warner, Green Chemistry ; Theory and Practice, Oxford University Press, Oxford, 1998.

2. S. L. Y. Tang, R. L. Smith and M. Poliakoff, Green Chem., 2005, 7, 761.

3. P. T. Anastas and J. B. Zimmerman, Environ. Sci. Technol., 2003, 37, 94A.

4. S. Tang, R. Bourne, R. Smith and M. Poliakoff, Green Chem. 2008, 10, 268.

5. R.A.Sheldon, I.W. C. E. Arends and U. Hanefeld, “Green Chemistry and Catalysis”,Wiley-VCH, Weinheim, 2007.

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