Green Chemistry

• Green chemistry is the design of chemical products and processes that reduce or eliminate the generation of hazardous substances.
• Green chemistry is the utilisation of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products.
• There is an ever growing concern over the adverse effects of industrial chemicals and synthetic materials on human health and environment. The term “Safe” is difficult to define and the definition necessarily involves personal, institutional or social values and judgments.
• The Green Chemistry is the invention, design and application of chemical products and processes to reduce or to eliminate the use and generation of hazardous substances in any form.

Benefits  of  Green  Chemistry

Human Health

• Cleaner air and water : Less release of hazardous chemicals to atmosphere leading to less damage to environment.
• Increased safety for workers in the chemical industry; less use of toxic materials; less personal protective equipment required; less potential for accidents (e.g., fires or explosions).
• Safer consumer products of all types: new, safer products will become available for purchase; some products (e.g., drugs) will be made with less waste; some products (i.e., pesticides, cleaning products) will be replacements for less safe products.
• Safer food: elimination of persistent toxic chemicals that can enter the food chain; safer pesticides that are toxic only to specific pests and degrade rapidly after use.
• Less exposure to such toxic chemicals as endocrine disruptors.

Environment:

• Many chemicals end up in the environment by intentional release during use (e.g., pesticides), by unintended releases (including emissions during manufacturing), or by disposal. Green chemicals either degrade to innocuous products or are recovered for further use.
• Plants and animals suffer less harm from toxic chemicals in the environment.
• Lower potential for global warming, ozone depletion, and smog formation.
• Less chemical disruption of ecosystems.
• Less use of landfills, especially hazardous waste landfills

Economy and Business:

• Higher yields for chemical reactions, consuming smaller amounts of feedstock to obtain the same amount of product.
• Fewer synthetic steps, often allowing faster manufacturing of products, increasing plant capacity, and saving energy and water.
• Reduced waste, eliminating costly remediation, hazardous waste disposal, and end-of-the-pipe treatments.
• Better performance so that less product is needed to achieve the same function.
• Reduced use of petroleum products, slowing their depletion and avoiding their hazards and price fluctuations.
• Reduced manufacturing plant size or footprint through increased throughput.
• Increased consumer sales by earning and displaying a safer-product label (e.g., Safer Choice labelling).
• Improved competitiveness of chemical manufacturers and their customers

Green Chemistry  for  Cleaning Up Pollution

• Green chemistry reduces pollution at its source by minimizing or eliminating the hazards of chemical feedstocks, reagents, solvents, and products.
• If a technology reduces or eliminates the hazardous chemicals used to clean up environmental contaminants, this technology would qualify as a green chemistry technology.
• The Chemicals should always be applied in proper prescribed dosage and in Permissible limits only. We should understand the phrase-“A Poison is the Medicine if taken in Proper Dose & A Medicine is the Poison if not taken in Proper Dose”12 Principles of Green Chemistry

1. Prevent waste: Design chemical syntheses to prevent waste. Leave no waste to treat or clean up.
2. Maximize atom economy: Design syntheses so that the final product contains the maximum proportion of the starting materials. Waste few or no atoms.
3. Design less hazardous chemical syntheses: Design syntheses to use and generate substances with little or no toxicity to either humans or the environment.
4. Design safer chemicals and products: Design chemical products that are fully effective yet have little or no toxicity.
5. Use safer solvents and reaction conditions: Switch to safer solvents, separation agents, or other auxiliary chemicals.
6. Increase energy efficiency: Run chemical reactions at room temperature and pressure whenever possible.
7. Use renewable feedstock: Use feedstock that is renewable rather than depletable. The source of renewable feedstock is often agricultural products or the wastes of other processes; the source of depletable feedstock is often fossil fuels or mining operations.
8. Avoid chemical derivatives: Avoid using blocking or protecting groups or any temporary modifications if possible. Derivatives use additional reagents and generate waste.
9. Use catalysts, not stoichiometric reagents: Minimize waste by using catalytic reactions. Catalysts are effective in small amounts and can carry out a single reaction many times
10. Design Chemicals And Products to degrade after use: Design chemical products to break down to innocuous substances after use so that they do not accumulate in the environment.
11. Analyse in real time to prevent pollution: Include in-process, real-time monitoring and control during syntheses to minimize or eliminate the formation of by-products.
12. Minimize the potential for accidents: Design chemicals and their physical forms (solid, liquid, or gas) to minimize the potential for chemical accidents including explosions, fires, and releases to the environment.

Preventing Pollution & Sustaining the Earth

• Meeting the needs of the present generation without compromising the needs of future generations.
• Green chemistry: Technologies of the invention, design and application of chemical products and processes to reduce or to eliminate the use and generation of hazardous substances ,and where possible utilize renewable raw materials.
• As human beings - we are part of the environment. The way in which we interact with our environment influences the quality of our lives.

Industrial Applications of Green Chemistry

• Applications of green chemistry include the decrease or eliminate the use of solvents, or render them safer and more effective. Green chemistry has also motivated numerous ways to synthesize petroleum-based chemicals from biological materials instead, regularly plant matter or waste.
• Green chemistry has different industrial applications in Designing Safer Chemicals Production, Food & Flavour Industry, and Green Technologies in the Pharmaceutical Industry, Paper & Pulp Industry, Polymer Industry, Sugar & Distillery Industries, Textile and Tannery Industry and Green Chemistry in Agrochemicals.
• Green chemistry also plays an important role in alternate energy science, and the production of novel methods to make solar cells, fuel cells, and batteries for energy storage. Self-assembling molecules uses bio-based plant materials which also involves green chemistry principles.
• The main goal of green chemistry is to reduce or eliminate waste in the manufacture of chemicals and its allied products, which has inspired the design of green next generation catalysts. Other developments in green chemistry are the trend toward redesigning chemical products to reduce their risk.