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“Green Chemistry” A greener future…

“Green Chemistry” A greener future…. Prof. Ángela González Department of Biology, Chemistry and Env. Sciences Interamerican University of Puerto Rico San Germán Campus agonzal@sg.inter.edu. What to expect from this talk…. Why? History What? Definitions How? Principles Examples.

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“Green Chemistry” A greener future…

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  1. “Green Chemistry”A greener future… Prof. Ángela González Department of Biology, Chemistry and Env. Sciences Interamerican University of Puerto Rico San Germán Campus agonzal@sg.inter.edu

  2. What to expect from this talk… • Why? • History • What? • Definitions • How? • Principles • Examples Angela González, Ph.D. / UIA-SG

  3. ¿WHY? • 70’s – need to improve environmental quality • Control  Laws • Contaminants produced and THEN treated before releasing them to the environment • Excellent idea IF there is good control and handling of environmental laws • It is continuous, slow and expensive Remediation Techniques Angela González, Ph.D. / UIA-SG

  4. Angela González, Ph.D. / UIA-SG

  5. ¿WHY? • 1991 – Green Chemistry is promoted by EPA – (Paul Anastas) Prevention!!!! Angela González, Ph.D. / UIA-SG

  6. What is Green Chemistry? … or sustainable/environmentally benign chemistry is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances www.epa.gov/greenchemistry Angela González, Ph.D. / UIA-SG

  7. What is Green Chemistry? … principles to reduce or eliminate use or production of dangerous chemicals in the design, manufacture and application of chemical products. Green Chemistry Theory & Practice, P T Anastas & J C Warner, Oxford University Press 1998 Angela González, Ph.D. / UIA-SG

  8. Green Chemistry Goals • Reduction or elimination of • Waste • Toxic chemicals or processes • Energy use Angela González, Ph.D. / UIA-SG

  9. Green chemistry is looking to: Reduce Angela González, Ph.D. / UIA-SG

  10. Green Chemistry vs. Environmental Chemistry • Environmental Chemistry: • Study of sources, reactions, transport, effects and destruction of chemical compounds in the ground, water and air. Stanley Manahan, Env. Chemistry, 6th Ed. CRC Press. 2005 Angela González, Ph.D. / UIA-SG

  11. Environmental Regulations Environmental Chemistry Clean up Research Monitoring Prevention Green Chemistry Angela González, Ph.D. / UIA-SG

  12. Green Chemistry Benefits: • Reduced waste, eliminating costly end-of-the-pipe treatments • Safer products • Reduced use of energy and resources • Improved competitiveness of chemical manufacturers and their customers Angela González, Ph.D. / UIA-SG www.epa.gov/greenchemistry/

  13. What has happened? • 1996 Presidential Green Chemistry Challenge Awards -promote non contaminant technologies. • 1997 Green Chemistry and Engineering Conference • 1999 Journal “Green Chemistry” • Chemical and Engineering News • 2000 GCI integrated into ACS • 2000 Journal of Chemical Education Angela González, Ph.D. / UIA-SG

  14. and? • Until 2006 all the technologies nominated to the PGCCA had eliminated the use or production of: • 1.2 billion pounds of chemicals and solvents per year • Enough to fill 5000 train tanks or a 62 miles long train • 57 million pounds of CO2 has been reduced • equivalent to take out circulation 37000 cars. • 16 billion gallons of water per year have been saved 1.2 billions 57 millions 16 billions Angela González, Ph.D. / UIA-SG www.epa.gov/greenchemistry/

  15. Twelve Principles of Green Chemistry Paul Anastas and John Warner in Green Chemistry: Theory and Practice (Oxford University Press: New York, 1998).

  16. Twelve Principles of Green Chemistry:1. Prevent waste • Design chemical syntheses to prevent waste, leaving no waste to treat or clean up. • Easier than clean up, transport or store them • Transforming chemical reactions that incorporate the largest amount of the starting materials = Less waste! Angela González, Ph.D. / UIA-SG

  17. ¿What kind of industry is worst? • New Industries: • Large gain margins $$$ • More complex chemistry • More waste production Angela González, Ph.D. / UIA-SG R A Sheldon J Chem Tech Biotechnol 1997 68 381

  18. Possible sources of waste reduction: Inputs “eco-friendly” solvents, high purity reagents, solvent recycling. Production Optimization of reaction time, temperature and pressure. New synthesis pathways. Discharges Reduce water usage, improve filtering procedures and reuse waste products. Angela González, Ph.D. / UIA-SG

  19. Twelve Principles of Green Chemistry:2. Design safer chemicals and products: • Design chemical products to be fully effective, yet have little or no toxicity. • …chemicals that are less hazardous to human health and the environment are: • Less toxic to organisms and ecosystems • Not persistent or bioaccumulative in organisms or the environment • Inherently safer with respect to handling and use Angela González, Ph.D. / UIA-SG

  20. Twelve Principles of Green Chemistry: 3. Design less hazardous chemical syntheses: • Use and generate substances with little or no toxicity to humans and the environment. • Avoid reactions that give dangerous by-products Angela González, Ph.D. / UIA-SG

  21. Twelve Principles of Green Chemistry:4. Use renewable feedstocks: • Use raw materials and feedstocks that are renewable rather than depleting. • Agricultural products • Wastes of other processes; • Reduce dependency from fossil fuels (petroleum, natural gas, or coal) or are mined. Angela González, Ph.D. / UIA-SG

  22. Twelve Principles of Green Chemistry: 5. Use catalysts, not stoichiometric reagents: • They are selective • Catalysts are used in small amounts • Can carry out a single reaction many times. • Improve production and energy consumption • They are preferable to stoichiometric reagents, which are used in excess and work only once. Angela González, Ph.D. / UIA-SG

  23. Twelve Principles of Green Chemistry:6. Avoid chemical derivatives: • Avoid: • blocking or protecting groups or any temporary modifications if possible. • Derivatives use additional reagents and generate waste. Angela González, Ph.D. / UIA-SG

  24. Twelve Principles of Green Chemistry: 7. Maximize atom economy: • Final product contains the maximum proportion of the starting materials. There should be few, if any, wasted atoms. • Relation between atoms in the products and atoms in the reagents • Addition – good atom efficiency • Elimination – not so good… Angela González, Ph.D. / UIA-SG

  25. Atom Economy • Barry Trost, Stanford University • Evaluate the efficiency of the chemical transformation “Because an Atom is a Terrible Thing to Waste” Angela González, Ph.D. / UIA-SG

  26. Atom Economy How many of the atoms of the reactant are incorporated into the final product and how many are wasted? Angela González, Ph.D. / UIA-SG

  27. How a reactions efficiency is measured? Reaction Yield % yield = (actual quantity of products achieved) x 100 (theoretical quantity of products achievable) Atom Economy* % atom economy = (MWt of desired products) x 100 (MWt of all products) Angela González, Ph.D. / UIA-SG * B M Trost, Science 1991, 254, 1471

  28. Atom Economy H3C-CH2-CH2-CH2-OH + Na-Br + H2SO4 H3C-CH2-CH2-CH2-Br + NaHSO4 + H2O 1 2 3 4 5 6 % Atom Economy = (FW of atoms utilized/FW of all reactants) X 100 = (137/275) X 100 = 50% Angela González, Ph.D. / UIA-SG

  29. % Yield vs. atomic economy • % Yield = 43.7% • %Atomic Economy = 83.6% Angela González, Ph.D. / UIA-SG

  30. ChemicalReactionsandAtomicEconomy • Addition > Substitutions > Eliminations • Re-arrangements: 100 % efficient • Ex: Diels-Alder Angela González, Ph.D. / UIA-SG

  31. Twelve Principles of Green Chemistry:8. Use safer solvents and reaction conditions • Avoid: • solvents, • separation agents, • other auxiliary chemicals. • USE: innocuous chemicals. Angela González, Ph.D. / UIA-SG

  32. Solvents • Organic solvents = high VOC’s • Alternatives • Synthesis without solvents • Water • Supercritical fluids (CO2) • Ionic Liquids Angela González, Ph.D. / UIA-SG

  33. Dry Cleaning – Greener… • Initially gasoline and kerosene were used • Now use PERC • Future use Supercritical CO2 and CO2 surfactants Angela González, Ph.D. / UIA-SG

  34. Twelve Principles of Green Chemistry: 9. Increase energy efficiency: • Run chemical reactions at ambient temperature and pressure whenever possible. Angela González, Ph.D. / UIA-SG

  35. Twelve Principles of Green Chemistry: 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. Angela González, Ph.D. / UIA-SG

  36. Twelve Principles of Green Chemistry:11. Analyze in real time to prevent pollution: • Include in-process real-time monitoring and control during syntheses to minimize or eliminate the formation of byproducts. Angela González, Ph.D. / UIA-SG

  37. PAT:Process Analytical Technologies • Measure quality and execution properties DURING manufacturing • Information is gather continuously to improve process Angela González, Ph.D. / UIA-SG http://www.fda.gov/Cder/OPS/PAT.htm

  38. Pre - PAT • Analysis of raw materials, intermediates and final products • In case of problems: WHOLE lot rejected = A LOT OF WASTE!... A LOT OF $$$$!! Angela González, Ph.D. / UIA-SG

  39. Like you do while cooking… • While you cook you test the food, and apply the needed corrections to improve it: • If it is too salty: … • If it is too bland: …. • If you have extra guest… • If it is too acidic: stop there… Angela González, Ph.D. / UIA-SG

  40. PAT: Process Analytical Technologies • Helps to: • Understand the process • Make corrections in the moment, without waiting for the final product • Develop mitigation strategies. Angela González, Ph.D. / UIA-SG

  41. Twelve Principles of Green Chemistry: 12. Minimize the potential for accidents: • Design chemicals and their forms (solid, liquid, or gas) to minimize the potential for chemical accidents: • explosions, • fires, and • releases to the environment. Angela González, Ph.D. / UIA-SG

  42. Example of Green Chemistry Synthesis - Ibuprofen

  43. Ibuprofen SynthesisClassic Route • Demand: 13,000 TPY • Developed in 1960 • 6 steps reaction Angela González, Ph.D. / UIA-SG

  44. Ibuprofen SynthesisClassic Route • Atomic Economy: 32% • If this synthesis were to be used today, the amount of by-products per year: 27,000 TPY Angela González, Ph.D. / UIA-SG MORE WASTE THAN PRODUCT!!!

  45. Boots & Hoechst Synthesis of Ibuprofen – Green Route Developed to improve production: * 3 steps * No solvents * Catalytic vs. stoichiometric reagents * Recycling, reuse and recovery of byproducts and reagents (acetic acid >99%; HF >99.9%) Angela González, Ph.D. / UIA-SG

  46. Boots & Hoechst Synthesis of Ibuprofen – Green Route • Atomic Economy77% • Faster • More % yield • Less waste produced $$$$$$ Angela González, Ph.D. / UIA-SG And a happier environment

  47. Angela González, Ph.D. / UIA-SG

  48. Angela González, Ph.D. / UIA-SG

  49. What is green chemistry looking for? • Waste production minimization from the source • Use of catalysts • Use of non-toxic reagents • Use of renewable sources • Improvement of atomic economy • Use of non-solvent or environmental benign solvents Angela González, Ph.D. / UIA-SG

  50. Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and Practice; Oxford University Press: New York, 1998 • B M Trost, Science 1991, 254, 1471 • PAT: • http://www.fda.gov/Cder/OPS/PAT.htm • EPA: • http://www.epa.gov/greenchemistry/index.html • ACS Green Chemistry Institute: • http://acs.org • Michael Cann, University of Scranton: • http://academic.scranton.edu/faculty/CANNM1/greenchemistry.html Angela González, Ph.D. / UIA-SG

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