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INTRODUCTION TO Green chemistry ppt
- 1. A Presentation on GREENCHEMISTRY :- Introduction and Principles INDU YADAV M.PHARMA (1st YEAR) PHARMACEUTICAL CHEMISTRY 31/MPH/DIPSAR/2017 DELHI INSTITUTE OF PHARMACEUTICAL SCIENCES AND RESEARCH (DIPSAR)
- 3. Contents:- • History ofGreen Chemistry • Definition • 12 Principles of Green Chemistry • Recent Trends in Green Chemistry • Green Chemistry and India • Conclusion • References
- 4. A Brief History:- • 1962- Rachel Carson wrote scientific book, Silent Spring. It outlined the devastation that chemicals had on local ecosystems and inspired modern environment movement. • 1970- Richard Nixon established the U.S Environmental Protection Agency (EPA).Its first major decision was to ban the use of DDT and other chemical pesticides. • 1990-The Pollution Prevention Act passed • 1991- Paul T. Anastas coined term Green Chemistry • 1998 - “Twelve Principles of Green Chemistry” is published by Paul Anastas (of the EPA) and John Warner.
- 5. “Green chemistry isthe design of chemical products and processes that reduce or eliminate the generation of hazardous substances.” According to US EPA (United States Environmental Protection Agency)
- 6. DEFINITION:- Green chemistry isalso known as clean chemistry or benign and sustainable chemistry. Green chemistry is the utilization 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. It applies across the life cycle of a chemical product, including its design, manufacture, use, and ultimate disposal.
- 7. 12 Principles ofGreen Chemistry:- 1. Prevent waste 2. Design Safer Chemicals and Products 3. Design Less Hazardous Chemical Syntheses 4. Use Safer Solvents/Reaction Conditions 5. Increase Energy Efficiency 6. Use Renewable Feedstocks 7. Design Chemicals and Products that Degrade After Use 8. Analyze in Real Time to Prevent Pollution 9. Use Catalysts 10. Maximize Atom Economy 11. Avoid Chemical Derivatives 12.Minimize the Potential for Accidents
- 8. 1.Prevent Waste It isbetter to prevent waste than to treat or clean up waste after it has been created. Prevention principle, is the most important and the other principles are the “how to” to achieve it.
- 9. 2.Design Safer Chemicalsand Products Chemical products should be designed to preserve efficacy of function while reducing toxicity. The intrinsic hazard of elements and molecules is a fundamental chemical property that must be characterized, evaluated and managed as part of a systems-based strategy for chemical design.
- 10. 3.Design Less HazardousChemical Syntheses Synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment.
- 11. 4.Use Safer Solvents/ReactionConditions The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible and, innocuous when used. The object is to choose solvents that make sense chemically, reduce the energy requirements, have the least toxicity, have the fewest life cycle environmental impacts and don't have major safety impacts.
- 13. 5.Increase Energy Efficiency Energyrequirements should be recognized for their environmental and economic impacts and should be minimized. Synthetic methods should be conducted at ambient temperature and pressure. Energy—like thinking about how to arrange a synthesis to have the fewest number of steps, or use the lowest cost starting materials or any other aspect of interest to the synthetic or process chemist—is just another design parameter.
- 14. 6.Use Renewable Feedstocks Ourfossil fuels for carbon-based chemicals and materials are being rapidly depleted in a predictable manner with the expected rise of global populations. A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable.
- 15. 7.Design Chemicals andProducts that Degrade After Use 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. Biodegradation, hydrolysis, and photolysis can be designed into chemical products.
- 16. 8.Analyze in RealTime to Prevent Pollution Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances. The effective application of process analytical chemistry directly contributes to the safe and efficient operation of chemical plants worldwide.
- 17. 9.Use Catalysts A catalystis defined as “a substance that changes the velocity of a reaction without itself being changed in the process”. It lowers the activation energy of the reaction but in so doing it is not consumed. This means that it can be used in small amounts and can be recycled indefinitely, that is it doesn’t generate any waste.
- 18. For example:- Reductionof a ketone to the corresponding secondary alcohol using sodium borohydride or molecular hydrogen as the reductant.
- 19. 10.Maximize Atom Economy Syntheticmethods should be designed to maximize incorporation of all materials used in the process into the final product. Percent atom economy:- The percent atom economy is simply the formula weight of the desired product(s) divided by the sum of the formula weights of all the reactants. % Atom Economy = (FW of atoms utilized/FW of all reactants) X 100
- 20. 11.Avoid Chemical Derivatives Unnecessaryderivatization (use of blocking groups, protection/deprotection, temporary modification of physical/chemical processes) should be minimized or avoided if possible, because such steps require additional reagents and can generate waste. One of the best ways of doing this is the use of enzymes. Enzymes are so specific that they can often react with one site of the molecule and leave the rest of the molecule alone and hence protecting groups are often not required.
- 21. 12.Minimize the Potentialfor Accidents Safety can be defined as the control of recognized hazards to achieve an acceptable level of risk. This is also known as the “Safety Principle”. 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.
- 23. Recent Trends inGreen Chemistry:- • Directed Evolution-Green Chemistry and Biocatalysts • New Developments in Degradable and Recycled Polymers • Polymers from Carbon Dioxide • Green Chemistry and Oil-Based Paints • Green and Renewable Energy Sources • Greener Electrochemical Storage Systems
- 24. Directed Evolution-Green Chemistryand Biocatalysts In 2016 the biochemical engineer Frances Arnold Develop this technique and received the Millennium Technology Prize. This technology is basically used to create new and better proteins (enzymes for biocatalysis) in the laboratory that can be used for biocatalytic reactions. This technology have solved many important synthetic industrial problems by replacing less efficient synthetic methods and sometimes harmful technologies. It has been adopted in areas of Green Chemistry and renewable energy. For example, directed evolution is used to improve enzymes that convert cellulose or other plant sugars to biofuels and chemicals.
- 25. New Developments inDegradable and Recycled Polymers Plastic littering problems increased at a fast rate and plastic pollution of oceans became a serious and emerging issue of environmental pollution. The Green chemistry of polymers with degradable products and bio-based plastics are considered in the right direction for sustainability in the polymer field. Polymers from Carbon Dioxide Reducing anthropogenic carbon dioxide (CO2) emission has become an urgent environmental and climate issue of our age Carbon dioxide can be recovered on a large scale in carbon capture of power plants, burning fossil fuels, and in steam-reforming to produce hydrogen from water and coal.
- 27. Green Chemistry andIndia :- In India, there hasn’t been much emphasis laid on development or practicing of green chemistry. With the increasing levels of pollution in all forms due to rapid industrialization, there is a need to understand the need of green chemistry. There has been some research done by some groups like development of solid support reagents and catalysts useful for organic transformations at IICT, Hyderabad or the initiation of a program to develop green synthetic methods by designing reaction protocols without involving organic solvents by IACS, Kolkata.
- 28. Conclusion:- Green Chemistry isthe chemistry for the environment, including the production and use of less hazardous substances. It is based on 12 principles. All over the world, governments and industries are working with “green” chemists to transform the economy into a sustainable enterprise. Green chemistry may be the next social movement that will set aside all the world’s differences and allow for the creation of an environmentally commendable civilization
- 29. References:- • P.T. Anastasand J.C. Warner, Green Chemistry, Theory and Practice, Oxford University Press, Oxford, 1998. • https://www.acs.org/content/acs/en/greenchemistry/what -is-green-chemistry/principles/green-chemistry-principle- 11.html • https://www.epa.gov • https://www.thomasnet.com/articles/chemicals/green- chemistry-history