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Chlorofluorocarbons AKA CFCs final

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					CHLOROFLUOROCARBONS AKA
CFCS



By: Gajan Balakumar, Cindy Guo, Warren Viegas, Muhammad
Bajwa, Komal Sandu & Sidarth Aiyar
AIMS OF THE RESEARCH
 To investigate the reduction of Ozone in the
  stratospheric region of the atmosphere caused
  by the usage of Chlorofluorocarbons (CFCs).
 Are CFCs guilty for the climate change during
  the late 20th century?
 What lessons can be learned from our
  understanding of CFCs that can help us fight
  ozone depletion in the future?
 What alternatives are there for this compound?
INTRODUCTION
THE MIRACLE CHEMICAL

 CFCs were once known as „Miracle‟ Chemicals.
 First manufactured in the 1930s, and
  industries soon found a wide variety of
  applications for them due to their chemical
  unreactivity and heat-absorbing properties.
 Used as refrigerant‟s in AC‟s and other objects.
THE MIRACLE CHEMICAL CONT’D

 Are very handy in production since it cost less
  and no real natural resources required for
  production
 Organic bonding of Halo-Carbons, performed
  easily and efficiently in the labs.
 Were given the household name “Freon‟s”.
THEIR MISTAKE
 Scientists initially believed that CFCs would be
  harmless in the earth's atmosphere because of
  their chemical inertness.
 This and their lack of solubility in water, gives
  CFCs a long life span in the atmosphere (tens
  to hundreds of years)
 However, in the stratospheric region of the
  atmosphere, these molecule break down,
  where the UV rays are intense.
THEIR MISTAKE CONT’D
   The break down releases
    Chlorine which act as catalysts
    in the Ozone destruction
    (Reactions shown later on).
   The ozone layer is important to
    humans and other life on earth
    because it absorbs harmful UV
    radiation (acting as a sort of
    UV "shield").
   Long-term effects on humans'
    excessive UV exposure include
    skin cancer, eye damage
    (cataracts), and suppression of
    the immune system.
CHEMICAL REACTIONS
BACKGROUND INFO
 CFCs are completely manmade and produce
  them for use in their machines.
 The main method used to make CFCs is to take
  a methane or ethane based compound that
  has been chlorinated, i.e. has a chlorine
  attached to it, and react it with HF.
 The process to make the various types of CFCs
  is the same. The reaction varies only slightly for
  each different type of CFC.
CHEMICAL FORMULAS
   Trichlorofluoromethane: CCl4 + HF →CFCl3 + HCl
   Dichloro-difluoromethane: CCl4 + 2HF →CF2Cl2 + 2HCl
   Trichloro-trifluoroethane: C2Cl6 + 3HF →C2F3Cl3 + 3HCl
   Dichloro-tetrafluoroethane:: C2Cl6 + 4HF →C2F4Cl2 + 4HCl
   Chloro-pentafluoroethane: C2Cl6 + 3HF →C2F5Cl + 5HCl
BIOLOGICAL IMPACT
OZONE DEPLETION
 When CFCs reach stratosphere, dissolved by UV
  light to release Chlorine atoms
 Chlorine atoms act as catalyst --> each atom break
  down tens of thousands of ozone molecules
  before they exit stratosphere
 CFCs take approximately 15 years to reach upper
  atmosphere from ground level and stay there for
  up to a century.
 In 1973, chlorine found to be catalytic agent in
  ozone destruction
ACTION TAKEN
 March 1985, announced there was polar ozone
  depletion over Antarctica --> initiatives to freeze or
  diminish production of CFCs
 In 1980‟s, 30-40% decrease in stratospheric
  ozone.
 By spring of 1987, 50% ozone gone over antarctic
  continent
 In space, there is TOMS (total ozone mapping
  spectrometer), which has shown downward trends
  in ozone layer at all latitudes near tropics.
GLOBAL WARMING
 Greatest global warming potential among gases
  which induce global warming because they are
  persistent.
 CFCs absorb infrared radiation
 Each CFC molecule absorbs tens of thousands as
  much infrared radiation as Carbon Dioxide
  molecules
     CFC-11 is 3,000 - 12,000 as effective as carbon
      dioxide
     CFC-12 is 7,000 - 15,000 as effective as carbon
      dioxide
CFCS RAPIDLY ENTERED THE OZONE LAYER
DURING THEIR USE
HUMAN IMPACT

   can lead to increase UVB light on humans:
     immune   inhibition
     cataracts --> major cause of blindness in world,
      accounts for 50% of blindness (1994).
     skin cancer
EFFECT ON PLANT
 30-50% of all organisms affected by UVB light
  --> therefore, change in UVB light can cause
  mutations to organisms
 Increased UV may cause reduction in
  productivity of trees because it would affect
  their uptake of carbon dioxide from the
  atmosphere --> important because trees
  accounts for 80% of plant biomass productivity
  on earth.
ECONOMIC IMPLICATIONS
USES

   Coolants in refrigeration
    and air conditioners
   as solvents in cleaners
   for electronic circuit
    boards
   blowing agents in the
    production of foam (for
    example fire
    extinguishers)
   propellants in aerosols.
PRODUCTION
 The total U.S. production of chlorofluorocarbons
  was estimated to be 737 million pounds in
  1975
 Production of CFCs grew rapidly during the 20th
  century, growing from 42 kilo tonnes in 1950 to
  1260 kilo tonnes in 1988
 After their harmful effect on the ozone layer
  was discovered, production decreased to 147
  kilo tonnes in 1999
PRODUCTION CONT’D
   A ban was imposed on the use of CFCs in aerosol-spray
    dispensers in the late 1970s by the United States, Canada, and
    the Scandinavian countries.
   In 1990, 93 nations agreed to end production of ozone-
    depleting chemicals by the end of the century.
   In 1992 most of those same countries agreed to end their
    production of CFCs by 1996.
   However, production of CFCs is still going strong in the
    developing world, particularly in South Asia, and Africa, as a
    result of economic constraints
   Each year Americans dispose of roughly 13 million refrigerators
    and freezers and many of those contain chlorofluorocarbons
    (CFCs) that deplete the ozone layer and contribute to climate
    change
UN DECLARATION

 Their firm determination to take all appropriate
  measures to phase-out the production and
  consumption of all fully halogenated
  chlorofluorocarbons controlled by the Montreal
  Protocol, as adjusted and amended, as soon as
  possible but not later than 1997.
 London, 27-29 June 1990
THE UN’S SCHEDULE FOR REDUCTION OF CFC
PRODUCTION
Concentration of CFCs in ozone layer has begun to level off
MAJOR ALTERNATIVES
FLUOROCARBONS, GLOBAL INDUSTRY AND
ECONOMICS

   Fluorocarbons are the CFC replacement for the majority of the
    producer and user industries.
   Over US$25 billion has been invested in fluorocarbons to
    replace CFCs
   Industry has played a vital role in developing alternatives
   as long as chlorine and bromine
    emissions continue to decline, ozone
    levels in the stratosphere will return
    to normal by the middle of next
    century.
   continued use of these fluorocarbons
    is actively encouraged to allow further
    progress in CFC replacement,
    especially in the developing world.
PHYSICAL PROPERTIES
   Fluorocarbons liquids are colorless. They have a high density due to
    their high molecular mass, but less overall separation between F and
    C.
   They comprise of Low and weak intermolecular forces; which gives it
    low viscosity when compared to liquids of similar boiling point for e.g.
    H2O.
   They are immiscible with most organic solvents (ethanol and
    chloroform), but are miscible with hydrocarbons.
   They have a very low solubility in water, and water has a very low
    solubility in FlouroCarbons.
   The greater number of Carbon atoms, the increased amount of
    Boiling Point, density, viscosity etc. Except Gas solubility, all the
    physical properties have a positive correlation with the number of
    Carbons in FCs.
INDUSTRIES THAT RELY ON ALTERNATIVES
   Air Conditioning Industry: millions of offices, public buildings,
    hospitals, hotels, and apartment buildings depend on HFCs to meet
    ambient temperature requirements.

   Food: The importance of refrigeration to the food manufacture,
    distribution and retail industries is fundamental: it plays a vital role in
    ensuring that food reaches consumers both fresh and fit to eat.

   Aerospace & Electronic Industries: Previously dependent upon CFCs
    as solvents to achieve the very high levels of cleanliness required
    ensuring safe and consistent operation; these industries are now
    turning to HFCs and HCFCs. In fact, at present, they are often
    technically, environmentally and economically the best solutions.
INDUSTRIES THAT RELY ON ALTERNATIVES
CONT’D
   Insulation: Fluorocarbon-blown foams provide better
    insulation than other blowing agents being proposed, such
    as hydrocarbons or carbon dioxide. Used in different
    applications, (e.g. building construction, refrigerated
    transport, heating pipes) foams blown with fluorocarbons
    conserve energy efficiently, providing environmental and
    economic benefits.
    Medical: Due to their very low toxicity, a certain types of
    HFCs are developed as propellants replacing CFCs in
    metered dose inhalers (MDI) for asthmatics. Dry powder
    inhalers are able to replace only a comparatively small
    fraction of the widespread MDI applications.
CONCLUSION
   "My findings do not agree with the climate models
    that conventionally thought that greenhouse gases,
    mainly CO2, are the major culprits for the global
    warming seen in the late 20th century, Instead, the
    observed data show that CFCs conspiring with cosmic
    rays most likely caused both the Antarctic ozone hole
    and global warming. These findings are totally
    unexpected and striking, as I was focused on studying
    the mechanism for the formation of the ozone hole,
    rather than global warming.”- Qin- Bing Lu, professor
    of physics and astronomy at the University of
    Waterloo
CONCLUSION/ REFLECTION
   CFCs are one of the first examples of man made chemicals contributing to
    the global warming and depleting ozone layer phenomena
   Through the collection of data, we were able to see that many “designer
    chemicals” that have integrated themselves in society have moral, ethical,
    social, economic and environmental implications, that should be continued
    to be researched
   Also, it is important to note when tackling such problems, the entire
    international community must be involved in one global initiative to
    decrease the use of CFCs, However differing economic, social and
    environmental situation must be accounted for
   It is necessary for the scientific community to monitor and research how
    humanity‟s applications of science affect the sustainability of the earth
   Aside from developing alternatives, political action and global mandates are
    very effective in curbing the use of these chemicals, though are subject to
    change as time progresses
PERSONAL REFLECTION
   Our study of CFCs has led to conclude that there are definitely
    ways to curb human dependence on ozone depleting
    chemicals, by researching as a team we looked into various
    perspectives on this issue, and believe maintaining the earth‟s
    sustainability will always be a collective effort regardless of
    approach. The reduction of CFCs are regarded as a scientific as
    well as political triumph, showing how taking responsibility as
    global citizens is very important when pursuing scientific
    endeavours. However, the impacts of CFCs will still be felt well
    into the next century, and as we look to the future we must
    heed the lessons of CFCs to find ways to lessen our
    dependence on chemicals that harm the earth.
BIBLIOGRAPHY
   Australia, Austria, Belgium, Canada, Denmark, Finland, Federal Republic of Germany, Liechtenstein, Netherlands,
    New Zealand, Norway, Sweden and Switzerland ( United nations delegates),. (1990, June 29). Declaration on
    chlorofluorocarbons (1990) . Retrieved from
    http://ozone.unep.org/Publications/MP_Handbook/Section_3.8_Annexes_Declarations/Declaration_on_CFCs.shtml
   Harrison, Emily. (2008). Unlikely victims of banning cfcs--asthma sufferers. Scientific American, 4(3), 1-2
   ASRAE. (2006, November 10). Government affairs update- 11/10/06 . Retrieved from
    http://www.ashrae.org/advocacy/page/1213
   Government of Canada, . (2005). Stratospheric ozone. State of the Envirioment infobase, 1(1), Retrieved from
    http://www.ec.gc.ca/soer-ree/English/indicator_series/new_issues.cfm?issue_id=5&tech_id=21
   Rowlands, Ian. (1993). The Fourth meeting of the parties to the montreal protocol: report and reflection. CIESIN, 1(1),
    1-2.
   Cohen, Jarrett. (2001). Chemistry in the skies. Insights magazine, Retrieved from
    http://ct.gsfc.nasa.gov/insights/vol17/chemistry.html
   Morris, John. (2009). Study shows cfcs, cosmic rays major culprits for global warming . In sciences, 1(1), Retrieved
    from http://insciences.org/article.php?article_id=8012
   Elkins, James. (1999). Chlorofluorocarbons (cfcs). Earth system research laboratory, 1(1), Retrieved from
    http://www.esrl.noaa.gov/gmd/hats/publictn/elkins/cfcs.html
   Cagin, S., and P. Dray, Between Earth and Sky: How CFCs changed our world and threatened the ozone layer, 512
    pp., Pantheon Press, New York, 1993


				
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