Green Chemistry

Green chemistry , based on the definition by the USEPA, is a philosophy of chemical research and engineering that encourages the design of products and processes that minimize the use and generation of hazardous substances. 

There are 12 principles involved in Green chemistry

1. Prevent waste: Design chemical synthesis, purification, analysis processes to prevent waste. Leave no waste to treat or clean up.
2. Design safer chemicals and products: Design chemical products that are fully effective yet have little or no toxicity.
3. Design less hazardous chemical syntheses: Design chemical syntheses, purifications, analyses that generate substances with little or no toxicity to either humans or the environment.
4. Maximize atom economy: Design syntheses so that the final product contains the maximum proportion of the starting materials. Waste few or no atoms.
5. Use safer solvents and reaction conditions: Avoid using solvents, separation agents, or other auxiliary chemicals. If you must use these chemicals, use safer ones.
6. Increase energy efficiency: Run chemical reactions at room temperature and pressure whenever possible.
7. Use renewable feedstocks: Use feedstocks  (also known as starting materials) that are renewable rather than depletable. The source of renewable feedstocks is often agricultural products or the wastes of other processes; the source of depletable feedstocks is often fossil fuels (petroleum, natural gas, or coal) or mining operations.
8. Avoid chemical derivatives: Avoid using blocking or protecting groups or any temporary modifications if possible. Derivatives use additional reagents and generate waste.
9. Use catalysts, not stoichiometric reagents: Minimize waste by using catalytic reactions. Catalysts are effective in small amounts and can carry out a single reaction many times. They are preferable to stoichiometric reagents, which are used in excess and carry out a reaction only once.
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 byproducts.
12. Minimize the potential for accidents: Design chemicals and their physical forms (solid, liquid, or gas) to minimize the potential for chemical accidents including explosions, fires, and releases to the environment.