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Chemical Exposure & Environmental Contamination PowerPoint Presentation
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Chemical Exposure & Environmental Contamination

Chemical Exposure & Environmental Contamination

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Chemical Exposure & Environmental Contamination

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Presentation Transcript

  1. Chemical Exposure & Environmental Contamination Chapter 3 • How are chemicals released into the environment? • What are the impacts on the environment? • The list of potentially hazardous compounds is large BUT many organic compounds are not harmful • Volatility (inhalation) • Solubility (particularly water)

  2. Chemical Exposure & Environmental Contamination • Volatile Organic Compounds (VOCs) • Solvents, plasticizers, cleaners, air deodorants, paints, smoking, driving • Emissions • Air, water, and soil pollution • So, what can we do?

  3. Go Green!?? What does Going Green Mean? Going Green Becoming an Eagles Fan? Being a Frog?

  4. Introduction to Green Chemistry Chapter 5 • How do we deal with Chemical Exposure? • Traditional Approaches • Minimize risk by limiting exposure & reducing quantities used • “scrubbers” • Treatment of waste water • Incineration • Chemical treatment • Waste minimization

  5. Introduction to Green Chemistry • Green Chemistry Strategies • Minimize risk by striving to eliminate or reduce use & generation of hazardous substances Risk = f(exposure, hazard) • The 12 principles of green chemistry serve as a guide • Paul Anastas and John Warner

  6. 12 Principles of Green Chemistry • Waste Prevention • Atom Economy (Chapter 8) • Less Hazardous Chemical Synthesis (Chapter 8) • Designing Safer Products • Safer Solvents and Auxiliaries (Chapter 6) • Design for Energy Efficiency • Use of Renewable Feedstocks (Chapter 9) • Reduce Derivatives (Chapter 8) • Catalysis (Chapter 7) • Design for Degradation (Chapter 9) • Real-time Analysis for Pollution Prevention • Accident Prevention

  7. Green Chemistry Metrics How do we measure the “greenness” of a reaction? • Percent (Chemical) Yield • Atom Economy • How much of the reactants remain in the final product • Does not account for solvents, reagents, reaction yield, and reactant molar excess • Atom Efficiency

  8. Green Chemistry Metrics (cont) • Effective Mass Yield • What is benign? Who decides? • Ignores stoichiometry • E-Factor • Typically split into 2 sub-categories: organic & aqueous waste • Smaller is better