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Green Chemistry. Sponsored by:. “ Chemistry has an important role to play in achieving a sustainable civilization on earth.” — Dr. Terry Collins, Professor of Chemistry Carnegie Mellon University. Definition.
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“ Chemistry has an important role to play in achieving a sustainable civilization on earth.” — Dr. Terry Collins, Professor of ChemistryCarnegie Mellon University
Definition Green chemistry is the design of products and processes reducing or eliminating hazardous substances. Green Chemistry is a subset of Design for Environment applying innovative scientific solutions to product manufacturing.
Definition: An Industry Example Shaw’s Green Chemistry Goals • Develop a sustainable thermopolymer platform for the future. • Cradle to cradle sustainability of face fiber and backing—100% of the product. • No increase in price. No sacrifice of performance. No loss of design variety.
GREEN CHEMISTRY SUPPORTS SUSTAINABILITY BY: • Making chemicals safe for our health & environment, • Using industrial processes that reduce or eliminate hazardous chemicals, & • Designing more efficient processes that minimize waste
GREEN CHEMISTRY MEANS… • Preventing pollution before it happens rather than cleaning up the mess later. • Saving companies money by using less energy and fewer/safer chemicals, thus reducing costs & impacts of pollution. • Mitigating climate change, water & resource depletion, & growing demands for safer food and cleaner energy
Green Chemistry Principles Prevention: it is best to prevent pollution/waste 2. Atom Economy: synthetic methods should maximize the incorporation of all materials used in the process into the final product 3. Less Hazardous Chemical Syntheses: synthetic methods should use and generate non toxic substances
Green Chemistry Principles 4,5,6 Designing Safer Chemicals: products should be nontoxic & designed to effect their desired function Safer Solvents and Auxiliaries: auxiliary substances (e.g., solvents, separation agents) should be avoided and innocuous when used Design for Energy Efficiency: Run chemical reactions at ambient temperature and pressure
Green Chemistry Principles 7,8 7. Use of Renewable Feedstocks: raw material or feedstock should be renewable rather than depleting 8. Reduce Derivatives: Avoid unnecessary derivatization (use of blocking groups, protection/deprotection, temporary modification of physical/chemical processes) because such steps require additional reagents and can generate waste
Green Chemistry Principles 9,10 Catalysis: Catalytic reagents (as selective as possible) are superior to stoichiometric reagents which are used in excess and work only once 10. Design for Degradation: Chemical products should be designed so that at the end of their function they break down into innocuous degradation products
Green Chemistry Principles 11,12 11. Analyze in real time to prevent pollution: Include in-process real-time monitoring and control during syntheses to minimize or eliminate byproducts 12. Minimize accidents: Design chemicals and their forms (solid, liquid, gas) to minimize the potential for chemical accidents, releases, explosions, and fires
Recognizing Product Excellence:Presidential Green Chemistry Award Recipient Shaw EcoWorx™ Carpet Tile • Sustainable thermo-plastic platform for the future. • Closed-loop recovery of face yarn and all backing components. • No increase in price and no loss of performance or variety. http://www.epa.gov/greenchemistry/dsca03.html Shaw Industries is the world’s largest manufacturer of carpets for home and business – and leader in sustainability.
2. Oxidize catalyst until cup “breaks” The Design ProtocolThat Led to TAML® Catalysts 1. Design molecular “cup” thought to be suitable for attaining long-lived catalysts 3. Characterize broken cup and identify breaking point 4. Modify weak site to be more robust Designing Ligands for Oxidizing Complexes, T. J. Collins Accounts Chem. Res., 1994, 27, 279-285. TAML® Oxidant Activators: A New Approach to the Activation of H2O2 for Environmentally Significant Problems, T. J. Collins Accounts Chem. Res., 2002, 35, 782-790
TAML® Catalyst Features • formed from biochemically common elements – prototype exhibits v. low toxicity • beginning of “dial-a-lifetime” catalysis • economical to synthesize • water-soluble • usable from pH 1 to 13 • efficient users of peroxide —fast peroxidase/slow catalase • 10 US patents, >70 counting foreign nationalizations • effective at 0.1 to 4 ppm = nM to low mM • amenable to modifications for capturing novel selectivity • currently being produced for small scale commercial uses
TAML® Activators Are Broadly Useful Oxidation Catalysts TEXTILES dye bleaching, effluent decolorization PULP AND PAPER pulp bleaching, effluent AOX and color removal WATER CLEANING halogenated aromatics and organics destruction LAUNDRY Dye transfer inhibition, stain removal PETROLEUM REFINING rapid oxidation of sulfur contaminants, other uses plus CHEM/BIO DEFENSE Rapid destruction of chem-bio warfare/terrorism agents
Recognizing Product Excellence:Presidential Green Chemistry Award Recipient Shaw EcoWorx Carpet • PVC & polyurethane substitute for carpet backing • Made from nontoxic polyolefin • Recyclable & contains fewer harmful chemicals • http://www.epa.gov/greenchemistry/dsca03.html
EcoWorx™ Production EcoWorx represented 70% of all carpet tile production at Shaw by the end of 2003 In June 2004 Shaw announced it would exit PVC use by year-end in favor of the EcoWorx sustainable metallacene catalyzed polyolefin compound.
EcoWorx™Carpet Tile Backing Chemistry Fiber Chemistry • LDPE - flexible base polymer • HDPE/MAH - adhesion and filler compatibility • Alaphatic tackifier - adhesion and flow modification • Coal Fly Ash – inorganic filler • Oil – adhesive compatibilizer • Nylon 6 – caprolac-tam monomer • 25% postindustrial recycled content • Over 20 million lbs of recovered nylon used in 2003 • N6 depolymerization by Honey-well • recovered caprolactam repolymerized Grinding and airflow separate backing from fiber for sustainable recycling
IN SUMMARY,GREEN CHEMISTRY IS… • Scientifically sound • Cost effective & • Leads toward a sustainable civilization
For further information on real world green chemistryhttp://www.chemistry.org/portal/a/c/s/1/acsdisplay.html?DOC=education\greenchem\cases.html For introductory readings in green chemistry http://www/chemistry.org/portal/a/c/s/1/ acsdisplay.html?DOC=education\greenchem\greenreader.html