How to Make Liquid Oxygen

The phrase 'liquid oxygen' seems quite queer to most of us. We usually think of oxygen in its gaseous state, as it is the air that we breathe, which helps us perform our daily functions. So what is this liquid oxygen? Liquid oxygen is oxygen cooled below -182.96 °C. Liquid oxygen was first discovered by a French chemist, Raoul Pierre Pictet. Oxygen was first liquefied in a stable state by Polish scientists Zygmunt Wróblewski and Karol Olszewski. Liquid oxygen cost in 2001 was $0.21/kg. Thus, we see that liquid oxygen price is quite reasonable.

How to Make Liquid Oxygen

While liquid oxygen (LOX) sounds like a very difficult compound, it is quite easy to make liquid oxygen. But, 'How to Make Liquid Oxygen?'. Normal air consists of two main gases, nitrogen and oxygen. Both these gases liquefy at very low temperatures. To cool these gases to such low temperatures, the air is compressed and cooled, then allowed to expand again. By repeating this process over and over again, we have to get these two gases cooled to -196 °C, which is the boiling point of liquid nitrogen. Thus, we see that the boiling point of liquid nitrogen is lower than that of liquid oxygen. The liquid so formed at -196 °C is a combination of liquid nitrogen and liquid oxygen. To separate the two, the liquid is slightly heated to a temperature between -196 °C and -182.96 °C, where nitrogen becomes gaseous again, while oxygen still remains liquid.

Liquid Oxygen Uses

Industrial Uses of Liquid Oxygen
Since oxygen is a well-known combustible gas, liquid oxygen is also used for similar combustion-related purposes. Liquid oxygen is used in combination with liquid hydrogen and kerosene as an oxidizing propellant in spacecraft rocket application due to its high specific impulse. Many modern rockets and space shuttles also use liquid oxygen. Liquid oxygen was also used as a propellant in the first Intercontinental Ballistic Missiles (ICBMs), but its use was discontinued because liquid oxygen is a cryogenic (of a very low temperature) liquid and needs to be replenished too often. Liquid oxygen was also used to prepare oxyliquit explosives. LOX is also used in steel production. Liquid Oxygen is a very important component of the oxyacetylene torch.

Liquid Oxygen Health and Medicinal Uses
Liquid oxygen is also used in various vitamin supplements. Sprays containing liquid oxygen are used on cuts and bruises, and to reduce itchiness. For people suffering from respiratory diseases, liquid oxygen therapy is used. It can also be used as a mouthwash as it has anti-bacterial qualities.

Liquid Oxygen Properties

• Molecular Formula: O2
• Molecular Weight: 31.999
• Boiling Point @ 1 atm: -297.4°F (-183.0°C, 90oK)
• Freezing Point @ 1 atm: -361.9°F (-218.8°C, 54oK)
• Density, Gas @ 68°F (20°C), 1 atm: 0.0831 lb/scf
• Density, Liquid @ BP, 1 atm: 71.23 lb/scf
• Specific Gravity, Gas (air=1) @ 68°F (20°C), 1 atm: 1.11
• Specific Gravity, Liquid (water=1) @ 68°F (20°C), 1 atm: 1.14
• Specific Volume @ 68°F (20°C), 1 atm: 12.08 scf/lb
• Solubility in Water @ 77°F (25°C), 1 atm: 3.16% by volume
• Expansion Ratio, Liquid to Gas, BP to 68°F (20°C): 1 to 860
• Latent Heat of Vaporization: 2934 BTU/lb mole

Thus, we can see that oxygen is a utile element not only in gaseous state but also in liquid state!