Published on February 20, 2008
Green Chemistry: Green Chemistry Safe, Reliable and Sustainable Sarah Newton Junior Chemistry Seminar The Need for Green Chemistry: The Need for Green Chemistry By 2050, estimated world population will be 10 billion, Dependence of the present world economy on a dwindling stream of nonrenewable natural resources, Persistent bioaccumulative pollutants, Health and safety of chemists and public, Ozone depletion, Loss of biological species in forests and in water, Changing climate, responsible for the as yet unpredictable changes in the hydrologic cycle. What can ‘Green’ Chemists do?: What can ‘Green’ Chemists do? Development of renewable energy technologies, Encourage the substitution of reagents made from renewable sources for those derived from fossilized carbon, Replace chemical polluting technologies with benign alternatives, Reduce persistent, environmental pollutants by creating technology that mimics biochemistry in its elemental balance. Twelve Principles of Green Chemistry: Twelve Principles of Green Chemistry 1. Prevention 2. Atom Economy 3. Less Hazardous 4. Designing Safer Chemicals 5. Safer Solvents & Auxiliaries 6. Design for Energy Efficiency 7. Use of Renewable Feedstocks 8. Reduce Derivatives 9. Catalysis 10. Design for Degradation 11. RT Analysis for Pollution Prevention 12. Inherently Safer Chemistry for Accident Prevention Renewable Resources: Renewable Resources Biomass as an abundant source for the production of chemicals and fuels. Biodiesel made from methyl esters of fatty acids, Fuel ethanol from wheat, Agroethanol AB plant in Sweden, Lactic acid to produce polymers and solvents, Platform molecule succinic acid, Sludge from paper mills converted to levulinic acid, a feedstock. Slide6: Credit: Mary Ann Ryan, Benign by Design, ChemMatters, 1999 (December), 9-11. Solvents: Solvents Green solvents: -Water -Ionic liquids -Bio-ethanol -Supercritical CO2 -Ethyl lactate Un-green solvents: -Toluene -Acetone -VOCs -Benzene Ethyl lactate Catalysts: Catalysts Homogeneous catalysis, Heterogeneous catalysis, Biocatalysis, Alternative catalysis involving photolysis, sonication and ultrasound technology, Catalytic reagents (as selective as possible) are more efficient than stoichiometric reagents, Example: chiral metal catalysts in synthesis of anti-inflammatory drug Naproxen, with 97% yield. Synthesis of Naproxen with chiral catalyst containing BINAP ligand: Synthesis of Naproxen with chiral catalyst containing BINAP ligand Credit: Anastas, P.T. The Role of Catalysis in the design, development, and implementation of Green Chemistry. Catalysis Today. Vol. 55. Jan. 2000. Green Chemistry Education: Green Chemistry Education Chemistry students need to be encouraged to consider the principles of Green Chemistry when designing processes and choosing reagents, Interactive teaching units (ITU) have been developed specifically to introduce undergraduate students to green chemistry, There are numerous scholarships and grants available for researchers and young scholars who are furthering the goals of Green Chemistry. Conclusions: Conclusions Green chemistry has come a long way since it’s birth in 1991, growing from a small grassroots idea into a new approach to scientifically-based environmental protection. All over the world, governments and industries are working with ‘green’ chemists to transform the economy into a sustainable enterprise. Who knows? 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. References: References Vickery, J. Green Chemistry. 2004. University of Bristol. http://www.chm.bris.ac.uk/webprojects2004/vickery/index.htm American Chemical Society. Chemistry.org. Introductory Readings in Green Chemistry. 2006. Chemical and http://www.chemistry.org/portal/a/c/s/1/acsdisplay.html?DOC=education\greenchem\greenreader.html Chemical and Engineering News. Biocatalysis and Green Chemistry Gets Greener. May 2001 & May 2002. http://pubs.acs.org/cen Gupta, J.P. Inherently Safer Design. Green Chemistry. 1999. http://www.rsc.org/publishing/journals/GC/article.asp?doi=a908580g Collins, T. Toward Sustainable Chemistry. Science. 2001. 291. 48-49.