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 Structure: FluorineCarbon Chlorine

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!

MW BP °C / 76 Torr Latent Heat ToxicPsi at 0°C Psi at 50°C NH kJ/mole Yes 4atm20atm CO kJ/moleNo35atm>>60atm SO kJ/moleYes2atm9atm CF 2 Cl kJ/moleNo3atm12atm Refrigerant Properties:

Lab Synthesis of R-12: (1)CCl 4 + HF –SbCl 2 F 3 (catalyst) → CFCl 3 (Freon-11) + HCl + CF 2 Cl 2 (Freon-12) Used by Thomas Midgely of Dupont in Blew out a candle with R-12 at a 1930 ACS meeting! Catalyst: SbCl 5-x F x is a fluorinating catalyst. (2)SbCl 5 + excess HF ↔ HCl + SbFCl 4 ↔ HCl + SbF 2 Cl 3 ↔ HCl + SbF 3 Cl 2 ↔ HCl + SbF 4 Cl ↔ HCl + SbF 5 Antinomy Pentafluoride is the most effective fluorinator.

Environmental Problems: 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: (1) CCl 2 F 2 + hν (λ < 220 nm) → ·Cl + ·CClF 2 Basic Ozone Depletion: (2) O 3 + hν → O + O 2 (3) O 3 + Cl → ClO + O 2 (4) O + ClO → Cl + O 2 (5) Net: O + O 3 → 2O 2 Polar Ozone Depletion: (6) 2ClO + M → Cl 2 O 2 + M (7) Cl 2 O 2 + hν → 2Cl + O 2 (8) 2(Cl + O 3 → ClO + O 2 ) (9) Net: 2O 3 + hν → 3O 2 CFC’s are linked to 2/3 of polar ozone loss! Ozone depletion gives you sun burns or worse!

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 CF 3 CH 2 F 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 CO 2 ) Example: CFC-12 has a GWP 100 =8500 and life=102 years FC-116 (C 2 F 6 ): ODP=0, GWP 100 =9500 & life=10000 years An alternative propellant for R-12 is CO 2 Additional alternative refrigerants are hydrocarbon mixes