JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Pharmacy III GREEN CHEMISTRY Previous Question Paper (March-2021 - R17)

Green chemistry is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. Its sustainability is anchored in the 12 principles, which aim to achieve environmental, economic, and social efficiency.

The key principles of sustainability in Green chemistry include:

1. Prevention: It is better to prevent waste than to treat or clean up waste after it is formed. For example, the synthesis of ibuprofen was improved to increase atom economy, reducing byproduct waste.
2. Atom Economy: Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. A high atom economy means less raw material is wasted.
3. Less Hazardous Chemical Syntheses: Whenever practicable, synthetic methods should 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 affect their desired function while minimizing their toxicity. An example is the development of safer pesticides that target specific pests without harming non-target organisms.
5. Safer Solvents and Auxiliaries: The use of auxiliary substances (e.g., solvents, separation agents) should be made unnecessary wherever possible and innocuous when used. Water or supercritical carbon dioxide are often used as green alternatives to toxic organic solvents.
6. Design for Energy Efficiency: Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized. This is achieved by conducting reactions 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. Examples include using biomass or agricultural waste instead of petroleum-based starting materials.
8. Reduce Derivatives: Unnecessary derivatization (use of blocking groups, protection/deprotection) should be minimized or avoided if possible, as such steps require additional reagents and generate waste.
9. Catalysis: Catalytic reagents (as selective as possible) are superior to stoichiometric reagents, as they can be used in small amounts and reused, significantly reducing waste.
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.

By integrating these principles, Green chemistry promotes a sustainable industrial framework that balances chemical innovation with ecological preservation and economic viability.