Halocarbons

In this group, halocarbons, consisting of chlorine, fluorine, and carbon, were the most common refrigerants (so-called chlorofluorocarbons, CFCs). Halons have been widely used as refrigerants, solvents, foam-blowing agents. The most common of CFCs were CFC-11, R-11, CFC-12 or R-12, CFC-113, R-113, CFC-114, R-114 and CFC-115 or R-115.

Although CFCs, such as R-11, R-12, R-22, R-113, R-114 were very common refrigerants in the refrigeration and air conditioning equipment they were used in a number of industries as aerosols, foams, solvents and others use Them sharply decreased because of their environmental impact. In recent decades, the phaseout of CFCs in the refrigeration became a major political issue, but also, technically speaking, more and more complex problems. In addition to the protection of the ozone layer, refrigeration and air conditioning industry, but there is another problem is the growth of greenhouse effect, which will be explained later.

It is well known that CFCs are odorless, non-toxic, and is heavier than air, but also dangerous if not handled properly. Inhalation of high concentrations not detected by human senses and can be fatal, because oxygen exceptions caused by CFC leakage indoors. The combustion products of CFCs, including phosgene, hydrogen fluoride, hydrogen chloride, which is highly toxic if inhaled. Although these CFCs are not identical in performance and composition, they are part of the same basic families of chemicals.

In this family there are other components, such as halons, carbon tetrachlorides, and per-fluorocarbons (PFCs). Halons are compounds consisting of bromine, fluorine, and carbon. In halons (i.e., halon 1301 and halon 1211) are used as fire extinguishing agents as for embedded systems and portable fire extinguishers. Production of halons was banned in many countries, for example, in the United States she ended 31 December 1993 due to the contribution of halons to the ozone depletion. They cause depletion of the ozone layer, because they contain bromine. Bromine is much more efficient than that Deplete the ozone than chlorine. Carbon tetrachloride (CCl4), compound consisting of one carbon atom and four chlorine atoms.

Carbon tetrachloride was widely used as a raw material in many sectors of industry including the production of CFCs, and as a solvent. The use of solvents ended when it was found to be carcinogenic. It is also used as a catalyst to deliver chlorine ions to certain processes. PFC-compound consisting of carbon and fluorine. PFCs have extremely high impact on global climate change and a very long service life. However, they do not Deplete stratospheric ozone, but concerns about their impact on global warming...