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What is Green Chemistry?

This information on green chemistry is meant to be a brief introduction. More information will be available on Ecology’s Hazardous Waste and Toxics Reduction web site in coming months. Green chemistry is a logical step in the right direction not only for environmental sustainability, but also social equity as it will reduce the amount of exposures to toxic products for workers and others. It has the potential to lead to many new and exciting jobs in designing safe products.

Definition: Green chemistry is the design of chemical products and processes to reduce or eliminate substances harmful to human health and the environment.

Green chemistry must accomplish three things :

1. Be more environmentally benign than the alternatives.
2. Be more economically viable than the alternatives.
3. Functionally outperform the alternatives.

Twelve Principles of Green Chemistry*

1. Prevent waste: Design chemical syntheses to prevent waste, leaving no waste to treat or clean up.
2. Design safer chemicals and products: Design chemical products to be fully effective, yet have little or no toxicity.
3. Design less hazardous chemical syntheses: Design syntheses to use and generate substances with little or no toxicity to humans and the environment.
4. Use renewable feedstocks: Use raw materials and feedstocks that are renewable rather than depleting. Renewable feedstocks are often made from agricultural products or are the wastes of other processes; depleting feedstocks are made from fossil fuels (petroleum, natural gas, or coal) or are mined.
5. Use catalysts, not stoichiometric reagents: Minimize waste by using catalytic reactions. Catalysts are used in small amounts and can carry out a single reaction many times. They are preferable to stoichiometric reagents, which are used in excess and work only once.
6. Avoid chemical derivatives: Avoid using blocking or protecting groups or any temporary modifications if possible. Derivatives use additional reagents and generate waste.
7. Maximize atom economy: Design syntheses so that the final product contains the maximum proportion of the starting materials. There should be few, if any, wasted atoms.
8. Use safer solvents and reaction conditions: Avoid using solvents, separation agents, or other auxiliary chemicals. If these chemicals are necessary, use innocuous chemicals.
9. Increase energy efficiency: Run chemical reactions at ambient temperature and pressure whenever possible.
10. Design chemicals and products to degrade after use: Design chemical products to break down to innocuous substances after use so that they do not accumulate in the environment.
11. Analyze in real time to prevent pollution: Include in-process real-time monitoring and control during syntheses to minimize or eliminate the formation of by-products.
12. Minimize the potential for accidents: Design chemicals and their forms (solid, liquid, or gas) to minimize the potential for chemical accidents including explosions, fires, and releases to the environment.

Green chemistry is an integral part of green product design which is designing products to minimize waste and toxicity at every stage in a product’s life cycle. Reducing toxics from products includes greening the supply chain. The supply chain is the system of organizations, people, technology, activities, information and resources involved in moving a product or service from supplier to customer. Greening the supply chain simply means that non-toxic processes are used at every step in the manufacturing of the new product.

For more information about Ecology’s role in promoting green chemistry, contact Ken Zarker at kzar461@ecy.wa.gov .

*Paul Anastas and John Warner, 1998. Green Chemistry: Theory and Practice, Oxford University Press: New York. Used with permission from the author.