Dr Mithun Nandi Assistant Prof & Head, Dept of Chemistry, Pandit Deendayal Upadhyaya Adarsha Mahavidyalaya, Eraligool, Karimganj, Assam

Oxygen is one of the basic chemical elements. In its most common form, oxygen is a colourless gas found in air. It is one of the life-sustaining elements on Earth and is needed by all animals. Oxygen is also used in many industrial, commercial, medical, and scientific applications. It is used in blast furnaces to make steel, and is an important component in the production of many synthetic chemicals, including ammonia, alcohols, and various plastics. Oxygen and acetylene are combusted together to provide the very high temperatures needed for welding and metal cutting. When oxygen is cooled below -297° F (-183° C), it becomes a pale blue liquid that is used as a rocket fuel.

Oxygen is also one of the most abundant chemical elements on Earth. About one-half of the earth's crust is made up of chemical compounds containing oxygen, and a fifth of our atmosphere is oxygen gas. The human body is about two-thirds oxygen. Although oxygen has been present since the beginning of scientific investigation, it wasn't discovered and recognized as a separate element until 1774 when Joseph Priestley of England isolated it by heating mercuric oxide in an inverted test tube with the focused rays of the sun. Priestley described his discovery to the French scientist Antoine Lavoisier, who experimented further and determined that it was one of the two main components of air. Lavoisier named the new gas oxygen using the Greek words oxys, meaning sour or acid, and genes, meaning producing or forming, because he believed it was an essential part of all acids.

In 1895, Karl Paul Gottfried von Linde of Germany and William Hampson of England independently developed a process for lowering the temperature of air until it liquefied. By carefully distillation of the liquid air, the various component gases could be boiled off one at a time and captured. This process quickly became the principal source of high quality oxygen, nitrogen, and argon.

In 1901, compressed oxygen gas was burned with acetylene gas in the first demonstration of oxy-acetylene welding. This technique became a common industrial method of welding and cutting metals. The first use of liquid rocket propellants came in 1923 when Robert Goddard of the United States developed a rocket engine using gasoline as the fuel and liquid oxygen as the oxidizer. In 1926, he successfully flew a small liquid-fueled rocket a distance of 184 ft (56 m) at a speed of about 60 mph (97 kph).

After World War II, new technologies brought significant improvements to the air separation process used to produce oxygen. Production volumes and purity levels increased while costs decreased. In 1991, over 470 billion cubic feet (13.4 billion cubic meters) of oxygen were produced in the United States, making it the second-largest-volume industrial gas in use.

Worldwide the five largest oxygen producing areas are the Western Europe, Russia, the United States, Eastern Europe and Japan.


Oxygen can be produced from a number of materials, using several different methods. The most common natural method is photo-synthesis, in which plants use sunlight convert carbon dioxide in the air into oxygen. This offsets the respiration process, in which animals convert oxygen in the air back into carbon dioxide. The most common commercial method for producing oxygen is the separation of air using either a cryogenic distillation process or a vacuum swing adsorption process. Nitrogen and argon are also produced by separating them from air. Oxygen can also be produced as the result of a chemical reaction in which oxygen is freed from a chemical compound and becomes a gas. This method is used to generate limited quantities of oxygen for life support on submarines, aircraft, and spacecraft. Hydrogen and oxygen can be generated by passing an electric current through water and collecting the two gases as they bubble off. Hydrogen forms at the negative terminal and oxygen at the positive terminal. This method is called electrolysis and produces very pure hydrogen and oxygen. It uses a large amount of electrical energy, however, and is not economical for large-volume production. Most commercial oxygen is produced using a variation of the cryogenic distillation process originally developed in 1895. This process produces oxygen that is 99+% pure. More recently, the more energy-efficient vacuum swing adsorption process has been used for a limited number of applications that do not require oxygen with more than 90-93% purity. Here are the steps used to produce commercial-grade oxygen from air using the cryogenic distillation process-----

AIR = 78% Nitrogen + 21% Oxygen + minor amount of some other gases + dust/impurities.......


In the process of Oxygen production in Oxygen Plant this 21% is seperated from our surrounding AIR by FRACTIONAL DISTILLATION under Cryogenic environment ( very very low temperature, say ~ -200°C) in liquid form...Then stored in respective oxygen cylinders and transported to the required destination for medical purposes......

oxygen diagram

Fig: Flowchart of Oxygen production

oxygen diagram oxygen diagram

How to use oxygen at Home

Oxygen Concentrators ( that are used at home for supply of ~ 5 LPM - 10 LPM of Oxygen ) also works in same mechanism i.e concentrating pure oxygen from Air under humid condition can be purchased and used at home (Cost : ~Rs 50,000 or more). But as suggested by experts for oxygen level less than ~90% in blood, oxygen cylinders should be used instead of concentrators.

Oxygen Concentrator

Role of Oxygen in COVID-19 treatment

During severe COVID-19, the oxygen levels in the body can get low. So, in order to keep the oxygen levels at the normal range, medical oxygen is needed. Now, when oxygen levels are low because of a sickness such as COVID-19, the cells in the body don't have enough oxygen to do their normal function as every cell of the body requires oxygen for normal function. So, if the oxygen levels are low for a long time and if it's not treated, then the cells themselves stop to work well and cells can actually die. So, then what can be seen is that every organs such as brain, heart, lungs, kidneys that requires oxygen starts to malfunction and in very extreme cases can even cause death. Thus the life saving treatment here is the medical Oxygen.


  1. Brady, George S., Henry R. Clauser, and John A. Vaccari. Materials Handbook, 14th Edition. McGraw-Hill, 1997.
  2. Handbook of Compressed Gases, 3rd edition. Compressed Gas Association, Inc., Van Nostrand Reinhold Co., Inc., 2009.
  3. Heiserman, David L. Exploring Chemical Elements and Their Compounds. TAB Books, 1992.
  4. Kent, James A., editor. Riegel's Handbook of Industrial Chemistry, 9th edition. International Thomson Publishing, 1997.
  5. Kroschwitz, Jacqueline I., executive editor, and Mary Howe-Grant, editor. Encyclopedia of Chemical Technology, 4th edition. John Wiley and Sons, Inc., 1993.
  6. Stwertka, Albert. A Guide to the Elements. Oxford University Press, 1996.