1,1,1-trichloroethane destruction

Scheme 17.2 By-products formation during 1,1,1-trichloroethane destruction on LaMn03+g. (Reprinted with permission from Ref. [51]. Copyright 2001, Elsevier.)...

The efficiency of the SCWO process for the destruction of EHMs was greater than 99.98%. Table 5 summarizes the data for EHM feed constituents, kerosene, polychlorotrifluoroethylene (PCTFE), trichloroethane (TCA), and photographic simulant. 

Catalytic hydrotreatment is widely used in the petroleum Industry to remove sulfur, nitrogen, and oxygen from crude oil fractions. However, its use to treat chlorocarbons has not been widely reported despite the widespread use of these compounds in industrial and military operations, and despite the negative environmental impact associated with most disposal options. Catalytic hydrotreatment has the potential to be a safe alternative for the treatment of chlorinated wastes and has advantages over oxidative destruction methods such as thermal incineration and catalytic oxidation. Some of these advantages include the ability to reuse the reaction products, and minimal production of harmful byproducts, such as CI2, COCI2, or fragments of parent chlorocarbons. 1,1,1- Trichloroethane was chosen for this research because it is widely used in industry as a solvent and is on the EPA Hazardous Air Pollutant list as a toxic air contaminant and ozone depleter. ... 

Rasmussen et al. 1983). 1,1,1 -Trichloroethane removed by rain water would be expected to re-volatilize rapidly to the atmosphere. Because of its long half-life of 4 years in the atmosphere (see Section 5.3.2.1), tropospheric 1,1,1-trichloroethane will be transported to the stratosphere, where it will participate in the destruction of the ozone layer. It will also undergo long-distance transport from its sources of emissions to other remote and rural sites. This is confirmed by the detection of this synthetic chemical in forest areas of Northern and Southern Europe and in remote sites (Ciccioli et al. 1993). 

In addition to the investigation of numerous model compounds, real wastes from chemical, pharmaceutical and food industry, from municipal sewage treatment plants, and from military and nuclear power facilities were tested in bench and pilot scale plants [110]. For a better understanding of supercritical water oxidation, single components like 2,4-dinitrotoluene, acetic acid, ammonia, aniline, cyanide, dichloromethane, ethanol, formic add, hexachlorocydohexane, hydrogen, phenol, PVC, DDT, pyridine, thiophene, toluene, trichloroethylene, and 1,1,1-trichloroethane were studied. From these experiments, kinetic data were obtained. The destruction efficiency, which is the ratio between the residual total organic carbon content (TOC) and the initial TOC achieved for these compounds is up to 99.999 % [83]. Also flames in supercritical water, e.g. by oxidation of methane with oxygen, have been studied [111, 112]. 

In the Fujiwara reaction chlorohydrocarbons react with pyridine (N-alkylation) under complete destruction of the ring. But the reaction path will go through a number of Schiff base intermediates, which, depending of the kind of analyte, have different life times and absorbances in the visible range. Thus mixtures of 1,1,1-trichloroethane, trichloroethylene, and chloroform could be resolved, even in the presence of unknown interfering substances. 

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