22.214.171.124. Sources of Halocarbons
The CFCs and HCFCs are wholly anthropogenic and do not exist naturally. They have been widely used as propellants in aerosols, as blowing agents in foam manufacture, in air conditioning units and refrigerants (CDIAC, 1991, 1993). The Montreal Protocol (click here) has recently cut emissions of many species by over 90%. Methylhalides are primarily produced in the oceans, usually associated with algal growth (Moore & Tokarczyk, 1993), although a significant fraction may come from biomass burning. Annual emissions of halocarbons may be found in IPCC (1995).
Halocarbons are still produced. There is a plant in River Edge, New Jersey. The production plant is in South Carolina. I am sure there are regular inspections that insure the proper use of the chemicals and their containment to prevent escape into the troposphere.
Halocarbon Products Corporation, (click here) a leading worldwide producer of specialty fluorochemicals and inhalation anesthetics, today announced that David Bacon will be joining the company as its new chief executive officer, effective April 28, 2015.
The following (click here) are just a few of the numerous applications that benefit from fluorochemistry:
- Pharmaceuticals – Fluorinated compounds have shown efficacy as antibacterials, antifungals, antibiotics, anesthetics, protease inhibitors and anticancer agents, among many other applications.
- Agricultural Chemicals – Fluorinated compounds are used as fungicides, herbicides and insecticides and often show more potency than their non-fluorinated analogues. The increased potency allows lower application rates.
- Advanced Photoresists – In the quest for finer features in semiconductor lithography, photoresist polymers incorporating fluorine and/or fluorinated substituents exhibit the best combination of optical transparency at shorter wavelengths, etch resistance and solubility.
- Liquid Crystals – For use in display devices, the addition of fluorine has been found to change viscosity, miscibility, electrical properties, steric characteristics and other qualities that are important to these devices.
- Fluorinated Surfactants – Utilized as emulsifying and dispersing agents, while related compounds are used as repellant finishes or soil-release finishes for textiles, these compounds rely on the ability of fluorine to alter surface-energy properties.
- Dyes – The addition of fluorine or fluorinated substituents, such as the CF3 group, has been found to improve the fixation yield, lightfastness and chemical resistance of dyes.
- Fluoroplastics and Fluoroelastomers – Used as coatings, vessel liners, films, wiring insulation, gaskets, seals, lab equipment and hoses because of their chemical and thermal stability.
- Ion-Exchange Membranes – Fluoropolymer membranes are used for enhanced chemical and thermal stability in harsh environments.