Green Chemistry Principles

Green chemistry is a specific type of pollution prevention that addresses the nature of chemical products and processes in order to lessen the risk to human health and the environment. It is the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances; in other words, it is environmentally benign chemistry. The risk associated with a chemical is a function of both its intrinsic hazard and exposure.

Traditionally, precautions have been taken to minimize exposure, both through personal protective measures as well as efforts to minimize environmental exposure, i.e. proper disposal. However, the hazard itself can also be minimized or reduced, thereby reducing the need to minimize exposure. "Green chemistry has also been described as the Hippocratic Oath for the Chemist, 'First, do no harm.'" (Anastas and Warner, 1998).

The Twelve Principles of Green Chemistry
from Green Chemistry: Theory and Practice by Paul Anastas and John Warner (Oxford University Press, 1998)

1. Prevention
   It is better to prevent waste than to treat or clean up waste after it has been created.
   
2. Atom Economy
   Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. 
   
3. Less Hazardous Chemical Syntheses
   Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no
   toxicity to human health and the environment.
   
4. Designing Safer Chemicals
   Chemical products should be designed to effect their desired function while minimizing their toxicity.
   
5. Safer Solvents and Auxiliaries
   The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible
   and innocuous when used.
   
6. Design for Energy Efficiency
   Energy requirements of chemical processes should be recognized for their environmental and economic impacts and
   should be minimized. If possible, synthetic methods should be conducted at ambient temperature and pressure.
   
7. Use of Renewable Feedstocks
   A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable.
   
8. Reduce Derivatives
   Unnecessary derivatization (use of blocking groups, protection/deprotection, temporary modification of physical/ chemical processes) should be minimized or avoided if possible, because such steps require additional reagents and can generate waste.
   
9. Catalysis
   Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.
   
10. Design for Degradation
    Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment.
    
11. Real-time Analysis for Pollution Prevention
    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. Inherently Safer Chemistry for Accident Prevention
    Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions, and fires.
    
    

Green Chemistry Institute

If you have any comments, questions, and/or are interested in participating in this project please email us at greenchem@mit.edu.

Tips for Sustainable Solvent Practices (PDF)

Generic Solvents Alternative Guide (PDF)