Fluorocarbon coolant

Fluorocarbons (FCs) Organic compounds analogous to hydrocarbons in which one or more hydrogen atoms are replaced by fluorine. FCs were once used in the United States as a propellant for domestic aerosols and are now found mainly in coolants and some industrial processes. FCs containing chlorine are called chlorofluorocarbons (CFCs). These are believed to be modifying the ozone layer in the stratosphere and are responsible for allowing more harmful solar radiation to reach the Earth s surface. 

After the run, a gel slice containing the RNA region is cut out with a scalpel or razor blade. The gel slice is put into the electrophoresis cell perpendicularly to the long axis, and set into the cell in a manner similar to that described above. The new acrylamide solution (20%) is poured into the cell and allowed to polymerise around and below the 10% strip. Because the 20% gel adheres tenaciously to the Perspex apparatus, it was found necessary to coat with fluorocarbon both the slot former and a region of about 2 cm around the two sides and bottom of the coolant plates that are in direct contact with the gel. Unless the cell is treated in this way, it is very difficult to remove the slot former after polymerisation or to dismantle the apparatus after the run. While the 20% gel polymerises, coolant is circulated to prevent the accumulation of air bubbles between the gel and the plates. Electrophoresis in the second dimension is carried out as in the first, but over a period of 17 hr at the same voltage. 

These hydro endcapped liquids (V, n = 1-7) were commercialized by DuPont as the Freon E series fluorocarbons for use as stable fluids, heat-transfer liquids, and dielectric coolants. The acyl fluorides were also converted into inert materials by dimerization with loss of the carbonyl group either electrochemically or photoche-mically (Eq 13.8). Both processes were used to make dimers and mixed dimers to tailor the boiling point of the flnal products. 

Examples of proposed DCC coolants include liquid butane for the seawater desalination process (section 8.4.7) and methyl ethyl ketone for the Dilchill lubricating oil dewaxing process (Bushnell and Eagen, 1975). Chlorinated hydrocarbons, fluorocarbons and CO2 have also found application in specific cases. 

Pappas and Million have described a gas chromatographic technique for the examination of mixtures of corrosive fluorides such as boron-, tri- and pentafluoride, free chlorine, chloryl fluoride, dichlorotetrafluoroethane, hydrofluoric acid and uranium hexafluoride. These workers used columns constructed of Teflon packed with a Teflon support and using either Kel-F or fluorocarbon oil as liquid phase. The technique was applied to halocarbon coolant analysis and in uranium fuel recovery. 

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