1 / 29

Chlorofluorocarbons

Chlorofluorocarbons. Products. Fredric Swarts. Early 1890s Belgian chemist Pioneer in synthesis of fluorinated alkanes Generated effective fluorine exchange agent. http://www.chemcases.com/fluoro/fluoro05.htm. Thomas Midgley Jr. 1930s

zavad
Download Presentation

Chlorofluorocarbons

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chlorofluorocarbons

  2. Products

  3. Fredric Swarts • Early 1890s • Belgian chemist • Pioneer in synthesis of fluorinated alkanes • Generated effective fluorine exchange agent http://www.chemcases.com/fluoro/fluoro05.htm

  4. Thomas Midgley Jr. • 1930s • Synthesized dichlorofluoromethane using “Swarts process” • Demonstrated that dichlorofluoromethane was neither toxic nor flammable by inhaling vapors and blew out a candle http://www.chemistryexplained.com/Fe-Ge/Freons.html

  5. Common CFCs • trichlorofluoromethane • dichlorodifluoromethane • trichlorotrifluoroethane • dichlorotetrafluoroethane • chloropentafluoroethane http://www.theozonehole.com/cfc.htm

  6. Before CFCs • Refrigerators used chemicals which were toxic or flammable or both • Since refrigerators were unsafe few people used them http://www.johnstonsarchive.net/environment/wrjp365o.html

  7. CFCs • Highly stable compounds • Used as propellants in spray cans, refrigeration units, air conditioners, solvents and foam-blowing agents • Organic compounds of carbon, fluorine, chlorine and hydrogen • Manufactured under the trade name Freon http://www.theozonehole.com/cfc.htm

  8. CFCs • Nontoxic • Nonflammable • Can be converted from a liquid to a gas and vice versa • Make styrofoam • Clean electronic equipment • Fire extinguishers http://www.eh-teaching.org/science/example.html

  9. This all sounds too good to be true! Lets add to that scientific history… In the 1930’s equally important chemistry was being discovered concerning Earth’s atmosphere.

  10. Sidney Chapman G.M.B. Dobson Both scientists that found and studied the ozone layer, what it does, and the processes that form it. http://www.atm.ox.ac.uk/user/barnett/ozoneconference/dobson.htm http://www.gi.alaska.edu/chapman/intro.html

  11. It wasn’t until the 1970’s that scientists found the problems of CFCs… • Frank Sherwood Rowland Mario J. Molina Won the Nobel Prize for Chemistry in 1995 with Paul J. Crutzen for their work on the formation and decomposition of ozone in the atmosphere. http://nobelprize.org/nobel_prizes/chemistry/laureates/1995/rowland-autobio.html

  12. Here’s what they found… Hair Spray

  13. Hair Spray Hair Spray Hair Spray

  14. Hair Spray

  15. Ozone DepletionWho cares?? • Ozone stops harmful light rays • This protects plants and animals from damage and death “Twenty Questions and Answers About the Ozone Layer: 2006 Update” D.W. Fahey Lead Author. June 2006 "Burn Barrels and Ozone Layer", St. Lawrence County NY EMC Poster Contest

  16. How bad can it get? • Observations of low levels of ozone began in the 1980’s • The depletion at the south pole grows to larger than Antactica “Twenty Questions and Answers About the Ozone Layer: 2006 Update” D.W. Fahey Lead Author. June 2006 • NASA Official: Paul A. Newman • Webmaster: Eric R. Nash (SSAI) • Please credit all images and animations to NASA, unless otherwise noted. • Last Updated: September 17, 2009

  17. CFCs in the ’70’s • Use of CFCs rose every year until the possible link between Ozone depletion and CFCs was announced • People began to choose not to use as many CFCs after this http://www.ciesin.org/TG/OZ/oz-home.html

  18. Proving the Connection • Doubt remained as to the connection between CFCs and the Ozone layer • In 1985 large amounts of ozone loss was reported   • In 1989 the connection was proven http://www.ciesin.org/TG/OZ/oz-home.html

  19. What could be done? • The Montreal Protocol was written and signed in 1987 to reduce CFC production and use • Nearly every country in the world has signed it • Calls to ban all CFCs “Twenty Questions and Answers About the Ozone Layer: 2006 Update” D.W. Fahey Lead Author. June 2006 http://www.purdue.edu/envirosoft/housewaste/house/chlorofl.htm http://www.ciesin.org/home-page/library.html

  20. In the USA • The US has met all of the goals set by the Montreal Protocol thus far • The US has developed and tested 300 alternative compounds EPA : Montreal Protocol “One-Page Fact Sheet”

  21. Alternatives to CFCs • HCFCs – can be broken down before they can destroy ozone “Twenty Questions and Answers About the Ozone Layer: 2006 Update” D.W. Fahey Lead Author. June 2006

  22. Did it work? • Total production of CFCs has decreased • The levels of CFCs in the atmosphere has decreased The NOAA Ozone Depleting Gas Index: Guiding Recovery of the Ozone Layer NOAA Earth System Research Laboratory, R/GMD, 325 Broadway, Boulder, CO 80305-3328

  23. Did it work? • The Ozone hole is still very large • Repair will be complete around 2075 “Twenty Questions and Answers About the Ozone Layer: 2006 Update” D.W. Fahey Lead Author. June 2006 • NASA Official: Paul A. Newman • Webmaster: Eric R. Nash (SSAI) • Please credit all images and animations to NASA, unless otherwise noted. • Last Updated: September 17, 2009

More Related