Chlorinated hydrocarbons Chlorofluorocarbons

Evidence that many of these compounds can have adverse effects on the immune, endocrine and nervous systems and that some are carcinogenic has grown during the last decade. The role of chlorofluorocarbons (CFCs) and of methyl bromide in the ozone layer depletion is well established (ref. 3).It is therefore not surprising that many halogenated derivatives are cast as environmental and health villains by various concerned groups who call for total phase out of chlorine and chlorinated hydrocarbons. 

Process Economics Program Report SRI International. Menlo Park, CA, Isocyanates IE, Propylene Oxide 2E, Vinyl Chloride 5D, Terephthalic Acid and Dimethyl Terephthalate 9E, Phenol 22C, Xylene Separation 25C, BTX, Aromatics 30A, o-Xylene 34 A, m-Xylene 25 A, p-Xylene 93-3-4, Ethylbenzene/Styrene 33C, Phthalic Anhydride 34B, Glycerine and Intermediates 58, Aniline and Derivatives 76C, Bisphenol A and Phosgene 81, C1 Chlorinated Hydrocarbons 126, Chlorinated Solvent 48, Chlorofluorocarbon Alternatives 201, Reforming for BTX 129, Aromatics Processes 182 A, Propylene Oxide Derivatives 198, Acetaldehyde 24 A2, 91-1-3, Acetic Acid 37 B, Acetylene 16A, Adipic Acid 3 B, Ammonia 44 A, Caprolactam 7 C, Carbon Disulfide 171 A, Cumene 92-3-4, 22 B, 219, MDA 1 D, Ethanol 53 A, 85-2-4, Ethylene Dichloride/Vinyl Chloride 5 C, Formaldehyde 23 A, Hexamethylenediamine (HMDA) 31 B, Hydrogen Cyanide 76-3-4, Maleic Anhydride 46 C, Methane (Natural Gas) 191, Synthesis Gas 146, 148, 191 A, Methanol 148, 43 B, 93-2-2, Methyl Methacrylate 11 D, Nylon 6-41 B, Nylon 6,6-54 B, Ethylene/Propylene 29 A, Urea 56 A, Vinyl Acetate 15 A. 

CFC CHC CIRPAS CMAQ chlorofluorocarbon chlorinated hydrocarbon Center for Interdisciplinary Remotely-Piloted Aircraft Studies community modeling of air quality... 

The HaHCs include the chlorofluorocarbons (CFCs) and their replacements — the hydrochlorofluorocarbons (HCFCs) and the hydrofluorocarbons (HFCs). Also included in the HaHC category are bromo- and iodo-substituted organic compounds and various chlorinated hydrocarbons (CHCs) such as chloroform, 1,1,1-trichloroethane, carbon tetrachloride. 

Hydrocarbon solvents, especially chlorinated hydrocarbons, and chlorofluorocarbon propellants all enhance the sensitivity of the myocardium to catecholamine-induced dysrhythmias. 

A subfamily of chlorinated hydrocarbons contains fluorine as well as chlorine and is called the chlorofluorocarbons or CFCs. Two examples of CFCs are dichlorodifluoromethane and trichlorofluoromethane. 

Bickle G, Suzuki T, Mitarai Y. Catalytic Destruction of Chlorofluorocarbons and Toxic Chlorinated Hydrocarbons. Appl Catal B Environ 1994 4 141-153. 

In preceding chapters ( Uses ) on chlorinated hydrocarbons and their derivatives it was pointed out, that the production and use of certain chlorofluorocarbons (CFC) and chlorofluoro-hydrocarbons (HCFC) was reduced or discontinued because of their influence on the ozone layer in the stratosphere. In this chapter these facts are discussed in more detail. 

Taketani, F., Takahashi, K., Matsumi, Y. Quantum yields for Cl( Pj) atom formation from the photolysis of chlorofluorocarbons and chlorinated hydrocarbons at 193.3 nm. J. Phys. Chem. A... 

R-Cl is a chlorinated hydrocarbon or chlorofluorocarbon which decomposes under the influence of UV light. Oxygen atoms involved in the second propagation step are abundantly present in the higher layers of the atmosphere, where they originate from photodissociation of O2 and NO2. Termination of the chain occurs if Cl reacts with hydrocarbons, or other H-containing molecules to HCl. 

There have been a number of subsitutions of chemicals in recent years, many of them driven by environmental concerns and regulations resulting from those concerns. One of the greater of these has been the substitution of hydrochloro-fluorocarbons (HCFCs) and hydrofluorocarbons (MFCs) for chlorofluorocarbons (Freons or CFCs) driven by concerns over stratospheric ozone depletion. Substitutions of nonhalogenated solvents, supercritical fluid carbon dioxide, and even water with appropriate additives for chlorinated hydrocarbon solvents will continue as environmental concerns over these solvents increase. 

Unlike petroleum hydrocarbons, organic compounds in general followed a different evolutionary path. Chlorinated solvents are a common group of organic compounds, and are also the most frequently encountered contaminant in groundwater. Common industrial chemicals that are characterized as chlorinated solvents include trichloro-ethene (TCE), 1,1,1-trichloroethane (TCA), tetrachloroethene (PCE) or perchloro-ethylene, chlorofluorocarbon (Freon)-113 (i.e., 1,1,2-trichloroethane or 1,2,2-tri-fluoroethane), and methylene chloride. In 1997, the EPA reported the presence of TCE and PCE in 852 of 945 groundwater supply systems throughout the United States and in 771 of 1420 Superfund sites. 

FLUOROCARBON. A number of organic compounds analogous to hydrocarbons, in which the hydrogen atoms have been replaced by fluorine. The term is loosely used to include fluorocarbons that contain chlorine these should property be called chlorofluorocarbons or fluorocarbon chlorides, since ii is these which arc though) to deplete the ozone layer or (he upper atmosphere. Fluorocarbons are chemically inert, nonflammable, and stable to heat up to 260-3l6°C. They are denser and more volatile lhan the corresponding hydrocarbons, and have low refractive indices, low-dielectric constants, low solubilities, low surface tensions, and viscosities comparable to hydrocarbons. Some arc compressed gases others are... 

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. 

Halocarbons, a class of polar solvents, are hydrocarbons with an attached halogen. There are commonly three types of halocarbon solvents those based on chlorine, fluorine, and a combination of the two. They are all powerful degreasing materials and can be particularly effective in removing polar contaminants from glass. The chlorofluorocarbons are currently under review because they cause environmental damage to the ozone layer.1... 

Oxidizer Chemical substance that causes oxygen to combine with another chemical substance examples include oxygen and hydrogen peroxide Ozone depletion Destruction of the stratospheric ozone layer that protects the Earth from harmful effects of ultraviolet radiation. Depletion of ozone layer is due to the breakdown of certain chlorine- and/or bromine-containing compounds (chlorofluorocarbons or halons), which break down when they reach the stratosphere and then catalytically destroy ozone molecules Ozone layer Protective layer in the atmosphere, about 15 miles above the ground. The ozone layer absorbs some of the sun s ultraviolet rays, thereby reducing the amount of potentially harmful radiation that reaches the Earth s surface PAHs Polycyclic aromatic hydrocarbons... 

Chlorine or other halogen bearing hydrocarbons (typically chlorofluorocarbons) defined as either class 1 or class 2 substances comprise the major stratospheric ozone depleting substances. EPA has established a midterm objective of an atmospheric chlorine content <2 parts per billion (ppb). 

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