Definition: Green Chemistry is utilization of a set principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical product.

Principles of green chemistry :

1. Prevention Prevention is better than cure. It is better to prevent waste than to treat or clean up waste after it has been created.

2. Atom Economy Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product..It is observed that most of the organic reactions release undesired product along with the useful product. The unutilized material is called as waste which causes trouble and process will not be economical. The Green chemistry requires that the new process should be designed in such a way that most of the starting material gets converted into products.

3. Less Hazardous Chemical Syntheses wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment. The starting material should be selected should be less toxic. β naphthyl and pyridine are carcinogenic ad needs to be avoided as starting material.

4. Designing Safer Chemicals Chemical products should be designed to affect their desired function while minimizing their toxicity. When medical formulations are to be put in the market, they put on trial basis to check effect on human.

5. Safer Solvents and Auxiliaries The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible and innocuous when used. It is necessary to avoid carcinogenic solvents, separation agents or auxiliary chemicals. Acetone , benzene , ether CCl4 and CHCl3 should be avoided.

6. Design for Energy Efficiency Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized. If possible, synthetic methods should be conducted at ambient temperature and pressure.