Trapped nitrogen

A 500-mL, three-necked, round-bottomed flask, equipped with a mechanical stirrer, condenser with Dean-Stark trap, nitrogen bubbler and a thermometer (Note 1), is charged with toluene (200 mL), (1 R,2S)-(-)-norephedrine (37.8 g, 0.25 mol), 1,4-dibromobutane (59.38 g, 0.275 mol) and sodium bicarbonate (46.2 g, 0.55 mol) (Note 2). The stirred heterogeneous reaction mixture is heated to reflux (105-118°C, Note 3) under a nitrogen atmosphere until completion of the reaction (Note 4). At the end of the reaction approximately 9 mL of water has collected in the Dean-Stark trap (Note 5). 

Mostcommercial helium is extracted from natural gas. The natural gas contains a significant amount of helium because large amounts of helium are trapped in the Earth by the radioactive decays of uranium. By cooling the natural gas, the methane is drained off as a liquid. At somewhatlower temperature the trapped nitrogen gas is also drained off as a liquid. Then only helium remains. Helium became famous as the gas for lighter-than-air balloons. It is now very important for low-temperature research,... 

Trapped nitrogen gas escapes while in an excited state and produces the radiation. 

The isotopic composition of this trapped nitrogen varies by up to 35% between different bulk samples as well as between different extraction steps of individual samples (Kerridge 1975 Clayton and Thiemens 1980). 

A mechanism for the acceleratory stage based on the catalytic effect of colloidal lead particles would agree with the model used to explain photolysis of alkali azides. Hall and Williams showed that metal films in contact with lead azide alter the photodecomposition efficiency [96]. Alernatively, the acceleratory stage may result from an increased concentration of trapped nitrogen molecules diffusing to the surface. The deceleration is thought to result from a depletion of azide molecules in the near-surface regions [120]. 

Triboluminescence (from the Greek word, tribos, a mbbing) is luminescence produced by a mechanical shock to a crystal. It is readily observed in striking or grinding sugar crystals in the dark. Trapped nitrogen gas escapes while in an excited state and produces the radiation. 

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