JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Pharmacy III Year GREEN CHEMISTRY Previous Question Paper (August - 2022 - R17)

Green chemistry is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. It aims to minimize the environmental impact of chemical manufacturing by focusing on efficiency, safety, and sustainability throughout the product life cycle.

The 12 principles of green chemistry include:

1. 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 Syntheses: Methods 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 affect their desired function while minimizing their toxicity.
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.
6. Design for Energy Efficiency: Energy requirements should be recognized for their environmental and economic impacts and should be minimized.
7. Use of Renewable Feedstocks: A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable.
8. Reduce Derivatives: Unnecessary derivatization (use of blocking groups, protection/deprotection) should be minimized or avoided if possible.
9. Catalysis: Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.
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.

Microwave-assisted synthesis is a green technique that utilizes electromagnetic radiation in the frequency range of 0.3 to 300 GHz to heat reaction mixtures. Unlike conventional heating, which relies on thermal conduction and convection, microwave heating involves direct interaction with polar molecules through dipole rotation and ionic conduction. This results in rapid, uniform, and volumetric heating, leading to significantly reduced reaction times, higher yields, improved purity, and the potential to use less hazardous solvents or solvent-free conditions.