Green Chemistry – History, Principles with Diagram
by Aravind E S, IIT Madras
Introduction
Green Chemistry is defined as the practice of chemical science and manufacturing in a manner that is safe,sustainable and non-polluting and that consumes minimum amounts of materials and energy while producing little or no waste material.Green chemistry, also called sustainable chemistry. The processing, production, use, and eventual disposal of chemical products may cause harm when performed incorrectly . The philosophy of chemical research and engineering that encourages the design of products and processes that minimize the use and generation of hazardous substances to humans , animals plants and the environment ,seeks to reduce and prevent pollution at its source.
Green Chemistry encourages the use of economical and eco-compatible techniques that not only improve the yield but also bring down the cost of disposal of wastes at the end of a chemical process. Green Chemistry increasing profits and promoting innovation while protecting human health and the environment. Applies to organic chemistry inorganic chemistry biochemistry analytical chemistry and even in physical chemistry focus on industrial applications
History
Concept-Trevor Kletz 1978; chemists should seek alternative processes to those involving more dangerous substances and conditions. Green Chemistry-Paul Anastas 1991
12 Principles in Green Chemistry
1. Pollution prevention- It is better to prevent waste than to treat or clean up waste after it is formed.
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 Synthesis – Whenever practicable, synthetic methodologies 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 preserve efficacy of the function while reducing toxicity.
5. Safer Solvents and Auxiliaries – The use of auxiliary substances (solvents, separation agents, etc.) should be made unnecessary whenever possible & innocuous when used .
6. Design for Energy Efficiency- Energy requirements should be recognized for their environmental and economic impacts and should be reduced. The 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 practical.
8. Reduce Derivatives – Unnecessary derivatization like blocking group, temporary modification of physical or chemical processes, protection or deprotection should be avoided whenever possible.
9. Catalysis – Catalytic reagents (as selective as possible) are superior to stoichiometricreagents.
10. Design for Degradation – Chemical products should be designed so that at the end of their function they do not persist in the environment and instead break down into innocuous degradation products.
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 – Substance and the form of a substance used in a chemical process should be chosen so as to minimize the potential for chemical accidents which include releases, explosions, and fires.
Examples
- Green Paints
- Green Plastics
- Green Carpets
Conclusion
- Pollution control
- Energy efficient
- Economy
- Less accidents
- Reduction of wastes
- Time consuming
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