Nitrogen liquid, boiling point

Pure hydrazine is a colourless liquid, melting point 275 K, and boiling point 387 K. It is surprisingly stable for an endothermic compound = -i- 50.6 kJ mol ). Each nitrogen atom has a lone pair of electrons and either one or both nitrogen atoms are able to accept protons to give and the less stable... 

Phosphine is a colourless gas at room temperature, boiling point 183K. with an unpleasant odour it is extremely poisonous. Like ammonia, phosphine has an essentially tetrahedral structure with one position occupied by a lone pair of electrons. Phosphorus, however, is a larger atom than nitrogen and the lone pair of electrons on the phosphorus are much less concentrated in space. Thus phosphine has a very much smaller dipole moment than ammonia. Hence phosphine is not associated (like ammonia) in the liquid state (see data in Table 9.2) and it is only sparingly soluble in water. 

Note Zero of entholpy ond of entropy token ot boiling point of liquid nitrogen, P=lotm.j T=7735°K. (-I95.8 C.)... 

To obtain the free base, 34 g (0.256 mol) of N-ethyl-3-piperidinol and 20 g (0.22 mol) of diphenylacetyl chloride were mixed in 80 cc of isopropanol and the solution was refluxed for 2 hours. The isopropanol was evaporated in vacuo at 30 mm pressure, the residue was dissolved in 150 cc of water and the aqueous solution was extracted several times with ether. The aqueous solution was then neutralized with potassium carbonate and extracted with ether. The ethereal solution was dried over anhydrous potassium carbonate and the ether removed by distillation. The product was then distilled at its boiling point 180° to 181°C at 0.13 mm of mercury whereby 14 g of a clear yellow, viscous liquid was obtained. The nitrogen content for CjiHjjNOj was calculated as 4.33% and the nitrogen content found was 4.21%. 

Rothschild W. G. Vibrational resonance energy transfer and dephasing in liquid nitrogen near its boiling point molecular computations, J. Chem. Phys. 65, 2958-61 (1976). 

Low-boiling-point materials can cause frostbite on contact with living tissue. While this is an obvious hazard with cryogenics, e.g. liquid nitrogen or oxygen, cylinders of other liquefied gases also become extremely cold and covered in frost as the contents are discharged. 

Usually, physisorption is carried out using nitrogen as an adsorbate at 77.3 K, the boiling point of liquid nitrogen. The solid material is called the adsorbent. Adsorption can be measured in many different ways. So-called volumetric adsorption, in which volumes of gas are introduced. sequentially while simultaneously measuring the pressure, is a commonly used technique. Fig. 3.41 shows a schematic of the equipment used (referred to as barometric equipment ). 

To increase the permeability of a certain region of the reservoir, the liquid-absorbed water is evaporated by heating the portion to a temperature above the boiling point of water, taking into account the ambient pressure [897,1487]. The liquid water is evaporated by injecting a water-undersaturated gas, such as heated nitrogen, into the reservoir. 

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