Nitrogen trifluoride disposal

Disposal of nitrogen trifluoride by exhausting it into water is impractical because it hydrolyzes very slowly and its solubility in water is very low. Venting into the atmosphere also should be avoided. Since nitrogen trifluoride is approximately three times as dense as air, it can settle out and cause local areas of high NF3 concentration [1]. 

Disposal of nitrogen trifluoride can be accomplished by combustion with a fuel such as activated charcoal, hydrocarbons, or metals at elevated temperatures. Reactions with activated charcoal produce nitrogen and carbon tetrafluo-ride. Carbon bed temperatures must be maintained above 1202°F (650°C) to assure reaction and to prevent gas adsorption. Similarly, nitrogen trifluoride streams can be scrubbed by introducing the gas through a packed bed of metals or metal oxides maintained at above 1000°F (538°C), followed by caustic scrubbing. 

Nitrogen trifluoride effluents have also been disposed of by introducing the gas stream below the flame of a burner operating on a hydrocarbon fuel. While nitrogen trifluoride is destroyed by this method, both hydrogen fluoride and oxides of nitrogen may be formed that require subsequent downstream scrubbing techniques for their removal. 

Commercial disposal systems are available for the destruction of nitrogen trifluoride. Because of the potential reactivity of nitrogen trifluoride at high temperature, a thorough analysis of the temperature and chemistry of the disposal process is necessary to ensure proper safe operation. 

Nitrogen trifluoride effluents have also been disposed of by introducing the gas... 

Method A 50 /jl (ca 250 ng) of the stock solution or of the purified extract is transferred into a reaction tube. One ml of boron trifluoride is added to the methanol, the cap is closed, and the tube is kept on a block heater (80°C) for 10 min. Two ml of water and 2 ml of -hexane are added. After thorough mixing, the layers are left to separate. Using disposable glass Pasteur pipettes, the upper layer is transferred to a clean, small vial. The extraction is repeated another two times with 2-ml portions of n-hexane. The hexane extracts are taken to dryness with a nitrogen stream, and the residue is dissolved in 1 -2 ml of injection solvent. Ochratoxin A is confirmed by the presence of an OA-methyl ester peak at delayed retention time and the disappearance of the OA peak (62). 

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