Carbon tetrachloride, three sensitizer

Solutions in organic solvents may, with certain reservations, be used directly, provided that the viscosity of the solution is not very different from that of an aqueous solution. The important consideration is that the solvent should not lead to any disturbance of the flame an extreme example of this is carbon tetrachloride, which may extinguish an air-acetylene flame. In many cases, suitable organic solvents [e.g. 4-methylpentan-2-one (methyl isobutyl ketone) and the hydrocarbon mixture sold as white spirit ] give enhanced production of ground-state gaseous atoms and lead to about three times the sensitivity... 

Semenov et al. [8] determined small amounts of petroleum products in chloroform extracts of non saline water by extracting the sample (200-500mL) followed by thin layer chromatography on alumina. He developed the chromatogram with light petroleum-carbon tetrachloride-acetic acid (35 155 1), and examined the plate in ultraviolet radiation the petroleum products exhibit three zones (pale blue, yellow and brown). Each zone is then extracted with chloroform, the fluorescence of the extracts measured and the results referred to a calibration graph. The sensitivity is O.lmg L. The infrared and fluorescence spectra of the zone obtained with various petroleum products are discussed. 

Carbon Tetrachloride Carbon tetrachloride (CCI4) was widely used as a dry cleaning solvent until its potential as a hepatotoxicant, nephrotoxicant, and carcinogen was recognized. Currently, carbon tetrachloride is used as an organic solvent. Nephrotoxicity associated with dermal or inhalation exposure to carbon tetrachloride is seen as acute tubular necrosis which is delayed in onset. Death occurs from acute renal failure, usually within three weeks of intoxication. Interestingly, humans appear to be more sensitive to acute carbon tetrachloride-induced nephrotoxicity than most animal models. 

Three new synthetic methods for the conversion of alcohols into azides (and hence potentially into amines) have been published. One route involves a further application of the chemistry of 2-alkoxypyridinium salts (formed in situ from an alcohol and the 2-fluoropyridinium salt) in their reaction with azide ion " (Scheme 17). Another extends the utility of the triphenylphosphine-ethyl diazodicarboxylate system, using diphenylphosphoryl azide as azide donor (Scheme 18), but is sensitive to steric hindrance at the alcohol carbon. The third route (Scheme 19) achieves oxygen activation through the alkoxyphosphonium salts (39), which are prepared from the alcohol, a phosphine, and a positive halogen donor such as carbon tetrachloride (with primary alcohols) or Af-chlorodi-isopropylamine (in... 

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