1 / 7

Dichlorodifluoromethane

Dichlorodifluoromethane. Synonyms: Freon-12, Genetron-12, Eskimon-12, CFC-12, R-12 ASHRAE Naming: American Society of Heating & Refrigeration Engineering [R or CFC or Brand]-(C-1)(H+1)F Example: Freon - 012. Structure: Fluorine Carbon Chlorine. The History of Ice.

kenley
Télécharger la présentation

Dichlorodifluoromethane

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. Dichlorodifluoromethane Synonyms: Freon-12, Genetron-12, Eskimon-12, CFC-12, R-12 ASHRAE Naming:American Society of Heating & Refrigeration Engineering [R or CFC or Brand]-(C-1)(H+1)F Example: Freon - 012 Structure: FluorineCarbon Chlorine

  2. The History of Ice Ice has always been important for things: • In the early 1900’s, ice was imported by ship to warm areas at around $500 / Ton! • Mechanical Ice Machines started to become popular around the mid 1900’s. • A mechanical refrigeration loop removes heat from a cold area with a pump, refrigeration gas, and a little physics. • Early refrigerants were toxic, corrosive and flammable: • Ammonia – Corrosive • Sulfur Dioxide – Stinks • Methyl Chloride – Burns ALTERNATIVES PLEASE!

  3. Refrigerant Properties:

  4. Lab Synthesis of R-12: (1) CCl4 + HF –SbCl2F3 (catalyst) → CFCl3 (Freon-11) + HCl + CF2Cl2 (Freon-12) Used by Thomas Midgely of Dupont in 1928. Blew out a candle with R-12 at a 1930 ACS meeting! Catalyst: SbCl5-xFx is a fluorinating catalyst. (2) SbCl5 + excess HF ↔ HCl + SbFCl4 ↔ HCl + SbF2Cl3 ↔ HCl + SbF3Cl2 ↔ HCl + SbF4Cl ↔ HCl + SbF5 Antinomy Pentafluoride is the most effective fluorinator.

  5. EnvironmentalProblems: • R-12 has been used for years as a propellant and refrigerant • Non-toxic due very to stable C-F & C-Cl bonds • Decomposes in the upper stratosphere: • CCl2F2 + hν (λ < 220 nm) → ·Cl + ·CClF2 • Basic Ozone Depletion: • (2) O3 + hν → O + O2 • (3) O3 + Cl → ClO + O2 • (4) O + ClO → Cl + O2 • (5) Net: O + O3 → 2O2 Ozone depletion gives you sun burns or worse! Polar Ozone Depletion: (6) 2ClO + M → Cl2O2 + M (7) Cl2O2 + hν → 2Cl + O2 (8) 2(Cl + O3 → ClO + O2) (9) Net: 2O3 + hν → 3O2 CFC’s are linked to 2/3 of polar ozone loss!

  6. What’s Being Done? • Montreal Protocol phased out CFC’s in industrial countries in 1996 • Kyoto Seeks to further restrict ozone depleting chemicals • CFC’s are replaced with fluorocarbons i.e. R-134a CF3CH2F • Problems with HFC’s: • C-F bonds absorb more IR radiation than C-Cl bonds • HFC’s have zero ODP and high GWP (relative to CO2) • Example: CFC-12 has a GWP100=8500 and life=102 years • FC-116 (C2F6): ODP=0, GWP100=9500 & life=10000 years • An alternative propellant for R-12 is CO2 • Additional alternative refrigerants are hydrocarbon mixes

More Related