Liquid oxygen
Liquid oxygen ( LOX in the aerospace, submarine and gas industry (of English Liquid Oxygen) ) is the liquid form of the element oxygen.
PREPARATION AND USE
Liquid oxygen is an industrial product and is commercially available. It is used to a great extent for industrial and medical purposes. Liquid oxygen is produced from the oxygen contained in the air by the Linde process by fractional distillation.
Due to the nature of cryogenic liquid oxygen he can make contact with these materials highly brittle. Liquid oxygen is also a strong oxidizing agent, as is excited singlet oxygen. Organic materials burn rapidly and strongly in liquid oxygen, and they can detonate unexpectedly when they come in contact with liquid oxygen, such as oil, grease or asphalt. Equipment for use or storage of liquid oxygen must therefore be completely free of grease and oil free.
Liquid oxygen as the oxidizing agent is a common propellant rocket in the space industry, usually. Associated with kerosene or liquid hydrogen as a fuel to be oxidized It is useful in this role because it creates a strong specific impulse. It was used in the very first rockets such as the V2 ( under the name of A- substance ) and engines from Redstone, R-7 and Atlas Semyorka.
Liquid oxygen was used in earlier built intercontinental ballistic missiles as well as in modern rockets, such as the main engines of the Space Shuttle. More modern ICBMs do not use liquid oxygen as the cryogenic properties and the need to have to refill the evaporating liquid oxygen on a regular basis, the operational readiness of missile negatively. Liquid oxygen was formerly used for the manufacture of explosives ( " Oxyliquit ").
Liquid nitrogen has a lower boiling point (-196 ° C, 77 K ) and oxygen ( -183 ° C, 90 K). On lines containing liquid nitrogen can condense oxygen from the air. The enriched oxygen may optionally react spontaneously with organic material. Liquid nitrogen or liquid air accumulate in open storage with oxygen, because it comes out of the atmosphere in liquid nitrogen.
Physical Properties
Liquid oxygen is extremely cold, has a weak blue color and is strongly paramagnetic. He has a density of 1.141 g / cm ³ ( 1.141 kg / L) ( at boiling temperature and atmospheric pressure 101.325 kPa ( ?)), And is moderately cryogenic ( freezing point: 50.5 K ( -222.65 ° C), boiling point: 90.188 K ( -182.96 ° C) at 101.325 kPa ( 760 mm Hg) ). Liquid oxygen has an expansion ratio of 860:1 at 20 ° C, and is therefore used in many commercial and military aircraft as a source of oxygen to breathe.
The Tetra oxygen molecule (O4 ) was first predicted by Gilbert N. Lewis in 1924, who suggested the molecule as an explanation for the liquid oxygen does not follow the Curie 's law. Computer simulations indicate that although no stable O4 molecules present in liquid oxygen, O2 molecules assemble into pairs with antiparallel spins, thus forming a temporary O4 units.
History
Louis Paul Cailletet and Raoul Pictet succeeded in the observation of droplets of liquid air and thus the evidence that could liquefy air. The resulting droplets evaporated spontaneously, however. Only Karol Olszewski and Zygmunt Wroblewski Florenty succeeded in 1883 at the Jagiellonian University in Poland as the first stable liquefaction of nitrogen, carbon dioxide and oxygen.