The 12 Principles of Green Chemistry are guidelines designed to make chemical processes and products more environmentally friendly and sustainable. They were formulated by Paul Anastas and John Warner in the 1990s. Here’s a detailed list with explanations:
- Prevention
- It is better to prevent waste than to treat or clean up waste after it is created.
- Example: Design reactions that produce minimal byproducts.
- Atom Economy
- Design synthetic methods to maximize the incorporation of all materials used in the process into the final product.
- Example: Use reactions that minimize side-products.
- Less Hazardous Chemical Syntheses
- Design synthetic methods that use and generate substances with little or no toxicity to humans and the environment.
- Designing Safer Chemicals
- Chemical products should be designed to achieve their desired function while minimizing toxicity.
- Example: Safer pharmaceuticals with fewer side effects.
- Safer Solvents and Auxiliaries
- Use safer solvents or eliminate them altogether, as solvents often contribute significantly to chemical waste.
- Example: Use water or supercritical CO₂ instead of toxic organic solvents.
- Design for Energy Efficiency
- Minimize energy requirements; reactions should occur at ambient temperature and pressure if possible.
- Example: Using microwave-assisted reactions instead of prolonged heating.
- Use of Renewable Feedstocks
- Raw materials should be renewable rather than depleting (e.g., biomass instead of petroleum).
- Reduce Derivatives
- Avoid unnecessary derivatization (e.g., blocking groups, protection/deprotection) which generates additional waste.
- Catalysis
- Prefer catalytic reagents over stoichiometric reagents, as catalysts can be used repeatedly and reduce waste.
- Design for Degradation
- Chemical products should break down into innocuous substances after use, avoiding environmental persistence.
- Real-time Analysis for Pollution Prevention
- Develop analytical methods to monitor and control chemical processes in real-time to prevent hazardous substances from forming.
- Inherently Safer Chemistry for Accident Prevention
- Choose substances and reaction conditions that minimize the potential for chemical accidents, explosions, fires, or releases.
These principles are widely used in green chemistry education, research, and industrial applications to make chemistry safer and more sustainable.