Liquid oxygen is an active, mobile (has a lower viscosity than water) blue substance with pronounced paramagnetic properties. This substance was obtained at the end of the 19th century, and since then it has found application in many fields, such as medicine or various industries.
Despite the fact that liquid oxygen in itself does not have a harmful effect on the environment, does not emit toxic substances, does not burn or explode, working with it requires compliance with safety regulations. The fact is that this element is a catalyst for the strong oxidation of other materials, which can lead to the ignition or explosion of other substances in oxygen-saturated air. Therefore, the premises in which work is carried out must be equipped with gas atmosphere control sensors and special exhaust ventilation.
It is necessary to know that prolonged exposure to air containing a high percentage of oxygen can cause damage to the respiratory system. Smoking is prohibited in these rooms and, in principle, open flames are not permitted. The clothes of a person who worked in a laboratory with high temperatures should be aired for at least half an hour. In addition, when using this substance, it is necessary to adhere to the general safety rules for working with cryogenic substances.
One of the most serious disadvantages of this substance is its refrigerant properties, which makes it difficult to use when working with materials that, when strongly cooled, change their characteristics dramatically. The temperature of liquid oxygen at normal atmospheric pressure is -183°C. This chemical element freezes at -218.8 ° C, after which it turns into pale blue crystals.
Liquid oxygen is used:
As an oxidizing agent, usually in conjunction with hydrogen or kerosene;
In medicine, as a preparation for manufacturing to provide the necessary microclimate, refueling special equipment, in the manufacture of preparations to enhance the growth of microorganisms, etc.;
In the engineering industry, liquid oxygen is used for various methods and cutting of metals;
In the metallurgical industry, it is used for the production of steel, alloys and non-ferrous metals, as well as for the reduction of iron;
It is used to improve the environmental situation: water purification, recycling of materials, waste oxidation;
In the chemical industry, it is used for the production of oxyliquites (explosives, now rarely used), various acids, acetylene and cellulose, as well as in the conversion of natural gas or methane.
Where to buy and oxygen?
There should be no problems with the purchase of these substances - liquefied gases can be bought in any city or ordered for their delivery. Another thing is that these substances are supplied in large cylinders with a volume of about 40 liters, so for home use you will have to look for other options.
- Liquid oxygen (LCD, English Liquid oxygen, LOX) is a pale blue liquid that belongs to strong paramagnets. It is one of the four states of aggregation of oxygen. Liquid oxygen has a density of 1.141 g/cm³ and is moderately cryogenic with a freezing point of 50.5 K (−222.65 °C) and a boiling point of 90.188 K (−182.96 °C). Liquid oxygen is actively used in the space and gas industries, in the operation of submarines, and is widely used in medicine. Typically, industrial production is based on the fractional distillation of air. The expansion ratio of oxygen from liquid to gaseous state is 860:1 at 20°C, which is sometimes used in breathing oxygen systems in commercial and military aircraft.
The main and practically inexhaustible source of obtaining liquid oxygen is atmospheric air: air is liquefied and then separated into oxygen and nitrogen.
Due to its cryogenic nature, liquid oxygen can cause brittleness in materials that come into contact with it. Liquid oxygen is also a very powerful oxidizing agent: organic matter quickly burns in its environment with a large release of heat. Moreover, some of these substances, when saturated with liquid oxygen, tend to explode unpredictably. Petroleum products often exhibit this behavior, including asphalt.
Liquid oxygen is a widely used oxidizing component in rocket fuels, usually in combination with liquid hydrogen or kerosene. Its use is due to the high specific impulse, which is obtained by using this oxidizer in rocket engines. Oxygen is the cheapest propellant component used. The first use took place in the German V-2 BR, later in the American Redstone BR and Atlas launch vehicle, as well as in the Soviet R-7 ICBM. Liquid oxygen was widely used in early ICBMs, but later versions of these missiles do not use it due to the cryogenic nature and the need for regular refueling to compensate for the boil-off of the oxidizer, which makes it difficult to launch quickly. Many modern rocket engines use LC as an oxidizer, for example RS-24, RD-180.
As sealing gasket materials in systems with liquid oxygen, materials are used that do not lose elasticity at low temperatures: paronite, fluoroplastics, annealed copper and aluminum. Storage and transportation of large quantities of liquid oxygen is carried out in stainless steel tanks with a volume of several tens to 1500 m³, equipped with thermal insulation. The outer, protective casing of thermal insulation can also be made of carbon steel. Reservoirs of transport tanks are also made of AMts alloy. The use of vacuum-powder or screen-vacuum thermal insulation makes it possible to reduce the daily losses of the boiling product to the level of 0.1 - 0.5% (depending on the size of the container) and the rate of temperature rise of the supercooled product - to 0.4 - 0.5 K per day. Transportation of boiling oxygen is carried out with an open gas discharge valve, and supercooled oxygen is carried out with a closed valve, with pressure control at least 2 times a day; when the pressure rises by more than 0.02 MPa (g), the valve opens.
Liquid oxygen was also used extensively in the manufacture of the Oxyliquit explosive, but it is now rarely used due to the large number of incidents and accidents.
To explain the deviation of the paramagnetic properties of liquid oxygen from the Curie law, the American physical chemist G. Lewis in 1924 proposed the tetraoxygen molecule (O4). To date, Lewis's theory is considered only partially correct: computer simulations show that although stable O4 molecules do not form in liquid oxygen, O2 molecules actually tend to associate in pairs with opposite spins, which form temporary O2-O2 associations.
Liquid nitrogen has a lower boiling point of 77 K (−196 °C) and devices that contain liquid nitrogen can condense oxygen
Liquid oxygen (LC, eng. Liquid oxygen, LOX) is a pale blue liquid, which belongs to strong paramagnetics. It is one of the four states of aggregation of oxygen. LC has a specific gravity of 1.141 g/cm³ and is moderately cryogenic with a freezing point of 50.5 K (−222.65 °C) and a boiling point of 90.188 K (−182.96 °C).
Liquid oxygen is actively used in the space and gas industries, in the operation of submarines, and is widely used in medicine. Typically, industrial production is based on the fractional distillation of air. The expansion ratio of oxygen to gaseous is 860:1 at 20°C, which is sometimes used in breathing oxygen systems in commercial and military aircraft. The main and practically inexhaustible source of obtaining liquid oxygen is atmospheric air: air is liquefied and then separated into oxygen and nitrogen.
General information.
In the periodic system of chemical elements of Mendeleev, oxygen is denoted by the symbol 0 (from the Latin Oxygenium). Under normal conditions, oxygen is a very active gas that is not perceptible by the human senses (i.e., it has no smell, taste or color). The oxygen molecule is usually diatomic (its formula is O2), less often triatomic (O3, this molecular state of oxygen is called ozone, this gas has a very specific smell). Oxygen is the most abundant chemical element on the planet. It not only fills the Earth's atmosphere by a quarter, but is also present in all the inner shells of the planet as part of silicates (silicon oxides that make up volcanic magma).
Discovery history
There is an exact date for the experimental discovery of oxygen - August 1, 1774, as stated by the Englishman Joseph Priestley. However, as often happens in chemistry, he did not realize the whole essence of his discovery, thereby partially giving the laurels of the discoverer to his colleagues.
In fact, the Swedish naturalist and pharmacist Karl Scheele (1771) was the first to discover oxygen three years earlier, when he set up an experiment on calcining saltpeter with sulfuric acid and then decomposing nitric oxide into its components: nitrogen and oxygen. Scheele gave the new gas the name "fiery air" but did not publish his experiments until 1777. By this time, Joseph Priestley had already carried out his experiments and announced his discovery, although he misinterpreted the results of his experiment. Both scientists told about their experiments to the greatest chemist of that time, Antoine Lavoisier. It was the latter who, in 1775, established that oxygen is a separate chemical element, and its diatomic molecule is part of atmospheric air. The works of Lavoisier forever refuted one of the main misconceptions in chemistry of that time, the theory of phlogiston, which they tried to explain the processes of combustion and oxidation of substances.
And the “official” discoverer Joseph Priestley became famous for the fact that, as part of his numerous experiments, he discovered several important chemical compounds for science at once, including carbon and sulfur oxides, ammonia and chlorine.
Properties of oxygen
The physical properties of oxygen under normal conditions characterize it as a colorless gas that is not perceptible to humans. It has a density of 1.429 kg/m3. Slightly soluble in water. When heated, the O2 molecule begins to reversibly dissociate into atoms: from 0.03% of all molecules at +2000 °C to 99.5% at +6000 °C.
In its liquid state, oxygen is a pale blue liquid that boils at 182.9°C. Solid oxygen has the form of blue crystals, the melting point of which is -218.7°C.
Oxygen is found in over 1500 compounds in the earth's crust. The oxygen atom is present in water and in living cells of all organisms on the planet. Oxygen is an extremely strong oxidizing agent and reacts with almost all other elements. The exceptions are inert gases and gold, which do not oxidize. As a result of interaction reactions with oxygen, oxides appear. Reactions proceed with the release of heat and are catalyzed with an increase in temperature, which leads to the combustion process.
The use of oxygen.
The use of oxygen in industrial production became possible with the invention of expanders in the middle of the last century. Expanders convert the potential energy of the gas into mechanical energy, while the gas does work and cools. Thus, air is liquefied and separated, resulting in nitrogen and oxygen.
Oxygen, being the strongest oxidizing agent, contributes to the complete combustion of fuel, which is used in various industries. Smelting metal from ore is impossible without the use of oxygen. Liquid oxygen is used as an oxidizer for rocket fuel, especially when mixed with ozone. Not only spaceships, but all modern aircraft cannot do without oxygen during flight. Over 10 tons of liquid oxygen are burned during one transoceanic flight.
In metallurgy, oxygen is used in the converter production of steel and rolled products. It is also necessary for gas-flame welding and cutting of metals. Used as an oxidizing agent in the synthesis of alcohols, aldehydes, ammonia in the chemical industry.
In the food industry, it acts as a propellant (for spraying other substances), as a packaging gas, and even as a food additive (E 948).
In medicine, it is used in special cylinders in a liquefied state for various purposes: it is used as an inhaler, eliminates hypoxia, enriches respiratory mixtures during anesthesia, and restores the functioning of the gastrointestinal tract (the so-called oxygen cocktails).
In fish farming, the aquatic environment is saturated with oxygen to increase productivity (in warm water, the oxygen content is lower than in cold water, but most commercial fish are not able to live at low temperatures in the aquatic environment).
Interesting Facts
The oxygen content in the modern atmosphere - 21% - is necessary and sufficient for the functioning of man as a living being. However, in large cities, the amount of oxygen is reduced to 17-18%. This is due to the lack of green plants, the photosynthetic activity of which just replenishes the balance of gaseous oxygen in the atmosphere. Under adverse meteorological conditions, the oxygen content in the city can drop to 10%, which is critical for our life. Indeed, at 7% oxygen content in the air, a person dies. The syndrome of lack of oxygen is called hypoxia and manifests itself in general weakness, fatigue, insomnia, decreased attention, frequent headaches and increased susceptibility to infections. It is believed that it is the lack of oxygen in the brain that causes depression.
A person has a reflex technique of a short-term increase in the amount of oxygen in the body - yawning. It is believed that we yawn precisely when the oxygen content in the brain drops below normal levels.
In mountainous areas, the air is thinner and the oxygen content is lower. In the course of evolution, the threshold of sensitivity to oxygen deficiency has decreased among the indigenous inhabitants of such territories. Therefore, residents of Nepal, Bhutan, Bolivia, Georgia feel great at altitudes above 3-4 kilometers, while representatives of other nationalities feel tired, nauseous, and when climbing higher they are forced to use oxygen masks. Oxygen is used in various fields of science, industry and agriculture.
Company Spetsservis LLC delivers liquid oxygen to any city in Russia.
Based on the terms of delivery and the required volume of products, we will be able to offer you the best price.
Liquid cryogenic products (liquid oxygen, nitrogen and argon) have a very low boiling point (at atmospheric pressure of about 90 K and below), which causes the main dangers in their use. Firstly, it is a physiological hazard when working on cryogenic equipment and with liquid and gaseous cryogenic products (the possibility of freezing). The human body is mainly made up of water. At low temperatures, water freezes and the resulting ice damages and destroys biological tissues. Therefore, when the surface of the body comes into contact with cryogenic liquids and gases at cryogenic temperatures, as well as with cooled surfaces (especially metal), so-called "cold burns" occur. The damage to the body is very similar to a burn, the degree of which depends on the time of contact with chilled objects or cryogenic liquids and a number of other factors. Insufficiently protected parts of the body in contact with uninsulated surfaces cooled to cryogenic temperatures can quickly freeze to them, and when pulled away, significant damage to the skin can occur. It is very dangerous to work with cryogenic products in wet clothes or gloves, as this can lead to frostbite. The mucous membranes of the eyes, nose, oral cavity and larynx are particularly sensitive to low temperatures. Therefore, it is very dangerous to inhale cold air, which can lead to serious lung diseases. The first sign of frostbite is a loss of sensation, usually accompanied by a change in the color of the frostbitten areas of the body to a waxy and pale yellow. After thawing, the frostbitten area becomes very painful, blisters appear on the skin, very susceptible to infection.
Operation at cryogenic temperatures requires special attention to structural materials, since under such conditions many of them significantly change their physical and mechanical properties. For widely used structural materials, as the temperature decreases, such characteristics as tensile strength, yield strength, fatigue limit, as a rule, increase, but plasticity indicators and, most importantly, impact strength decrease. As a result, many metallic materials tend to brittle fracture at low temperatures (fracture without noticeable macroplastic deformation, the phenomenon of cold brittleness). These materials include carbon and low alloy steels. In this case, the impact strength decreases so much that the use of steel of this group at temperatures below 230 K is unacceptable.
Cryogenic liquids are stored and transported in special vessels with high-quality thermal insulation (powder-vacuum or screen-vacuum). The color of the vessel and the inscription on it testify to which cryogenic product the vessel is intended. If it is necessary to use them for another cryogenic product, special measures specified in the manufacturer's technical documentation are carried out, including, for example, when switching from nitrogen to oxygen, degreasing the internal cavities and the evaporator.
Considering that during storage of liquid cryogenic products in vessels their constant evaporation occurs, it is necessary to take measures to exclude the possibility of an increase in pressure in the vessel. For this purpose, the vessels must be equipped with safety valves or safety diaphragms. In their absence, the gas outlet from the vessel must be constantly open.
Rapid heating of liquid cryogenic products in vessels with a narrow neck is unacceptable. Liquid cryogenic products should be handled very carefully, avoiding splashing and boiling. Personnel carrying out such work must be dressed in clean overalls, in which there are no external pockets, have glasses and mittens, trousers must be worn over shoes. The ingress of random objects into bathtubs and vessels with liquid cryogenic products must be completely excluded. Filling the vessels with liquid cryogenic product should be done carefully, avoiding intense boiling of the liquid. This is especially true for vessels with an open neck, since when they are quickly filled, liquid may be ejected into the room. The amount of liquid cryogenic product poured into the tank should not exceed 1.08 for liquid oxygen and 0.77 kg/dm3 for liquid nitrogen.
The transfer of liquid cryogenic products from one tank to another and their filling from transport tanks should be carried out on concrete platforms. It is strictly forbidden to carry out loading and unloading operations with cryogenic products on sites covered with asphalt due to the fact that the asphalt-liquid oxygen (or oxygen-enriched liquid) system is explosive and has a very low ignition energy.
When transfusing liquid cryogenic products into small vessels or Dewar vessels, special funnels should be used. The top of the funnel should be partially closed to reduce splashing of the liquid. When transfusing liquid cryogenic products, metal hoses should be used for any one liquid cryogenic product. The use of hoses for one and then for another liquid cryogenic product is not allowed. Hoses that are not in use must be plugged to prevent contamination and water ingress. The condition of the hoses should be checked regularly. At the end of the transfusion, the liquid cryogenic product must be completely removed from the hoses to avoid rupture in the event of a hermetic seal at both ends.
During the operation of vessels and tanks with liquid cryogenic products, it is necessary to constantly pay attention to the condition of pipelines and devices through which steam is removed from them. There are numerous cases when, as a result of freezing of atmospheric moisture and the formation of ice on the inner surfaces of the necks of the Dewar vessels and inside the discharge pipelines, the pressure in the vessels increased to dangerous values.
Sampling of liquid cryogenic products for analysis should be carried out in pre-chilled vessels. The vessels must be filled slowly, avoiding the ejection of liquids from the neck. Liquid cryogenic products have a temperature of 77-90K (196-183 °C). For this reason, they should be handled with care. Once on the skin, they quickly spread on the surface and cause severe cooling, which can lead to frostbite. Drops of liquefied gases in the eyes are especially dangerous, which leads to serious injuries. Short-term exposure of drops of a liquid cryogenic product to the skin does not cause skin damage due to the very low heat capacity of liquefied gases. However, the risk of frostbite increases significantly when drops of a liquid cryogenic product get behind the collar of clothing or inside shoes. When working with a liquid cryogenic product, it is necessary to protect the eyes with a face shield or goggles with side shields. Outerwear should be tightly closed, and trousers should cover shoes. It is dangerous to touch objects and walls of vessels cooled by cryogenic liquids with hands. In this regard, operations for pouring, pouring and transferring liquid cryogenic products should be carried out in asbestos, leather or canvas gloves, which should be put on the hand freely so that they can be easily thrown off if necessary. If liquid cryogenic products come into contact with an unprotected area of the body, it should be immediately washed with water.
In rooms where work with liquid cryogenic products is carried out, good ventilation and control over the oxygen content in the room air should be organized. It should be borne in mind that oxygen and argon at room temperature are much heavier than air. Therefore, in case of leaks into the room, the content of these gases in the pits and trenches can be significantly higher than the contents in the room. This necessitates the control of the oxygen content in the pits and trenches before people enter there to perform any work. After completion of work with liquid cryogenic products or a break in work for a significant time, vessels with liquid cryo-products must be removed from the room, and cryo-products should be drained from open baths and vessels. If, for any reason, vessels with cryoproducts were left in a closed room, personnel may only be allowed to enter it after monitoring the oxygen content in the room. It is strictly forbidden to pour liquid cryogenic products onto the floor of the premises due to the fact that their evaporation leads to significant pollution of the atmosphere of the room, as well as to cooling of the ceilings, which can lead to the destruction of the latter. Draining liquid oxygen indoors can cause a fire or explosion. Unused liquid cryogenic products must be drained into special evaporators or tanks. Draining them on the ground repeatedly led to strong explosions, since cryogenic liquids gradually impregnate the ground and can penetrate to a considerable depth, reaching combustible objects located there. In rooms where work is carried out with liquid cryogenic products, the necessary ventilation and regular monitoring of the oxygen content in the air must be provided. Any work is prohibited if the oxygen content in the air is more than 23% or less than 19%.
Liquid cryogenic products are classified as dangerous goods. Their classification according to the degree of danger according to GOST 19433-81 "Dangerous goods" and the features of their transportation are set out in the Rules for the transportation of inert gases and compressed and liquid oxygen by road.
Features of handling liquid oxygen.
Substances, such as wood, asphalt, which are impregnated with it and form the so-called oxyliquites, which are similar in their explosive properties to the most powerful explosives, are of particular danger when in contact with liquid oxygen.
The contact of liquid oxygen with oil, fats, and tissues is also dangerous. All equipment intended to handle liquid oxygen must be degreased and treated appropriately to remove solvent residues. When storing and using tools and equipment designed to work with liquid oxygen, ensure their cleanliness.
In rooms where work with liquid oxygen is carried out, posters "Caution, oxygen!" must be posted.
Repair of apparatuses, vessels, instruments and communications, in which liquid oxygen was located, can be carried out only after they are warmed up to positive temperatures and gaseous oxygen is removed from them by purging with air.
Equipment designed to work with liquid oxygen is strictly forbidden to be used to work with other cryogenic products, as it may be contaminated.
In rooms where work is carried out with liquid oxygen, it is strictly forbidden to smoke, light matches, use open flames and electric heaters with an open coil. Special posters should be posted in these rooms.
Clothing used for work with liquid oxygen should be stored in cabinets in special compartments, isolated from contaminated overalls. Clothing should hang freely. If it has been doused with liquid oxygen, it must be replaced with another one, and the oxygen-soaked clothing must be ventilated for at least 30 minutes.
When working with liquid oxygen, explosions repeatedly occurred due to the explosive nature of most organic substances in liquid oxygen, as well as the fact that many of them (asphalt, wood, cotton fabrics, sawdust) are impregnated with liquid oxygen, forming explosives (oxyliquites). For example, several explosions with very serious consequences are known, which occurred as a result of spills of liquid oxygen onto asphalt during its transfusion from one tank to another. During one of them, the explosion was initiated by the fall of a hammer on asphalt soaked in liquid oxygen. Explosions of great force were caused by spills of liquid oxygen on the wooden sleepers of the railway tracks. One of them was caused by a crack in the solder joint of a tube designed to take liquid oxygen for analysis. As a result, during the parking of the railway tank, liquid oxygen dripped onto the sleepers for quite a long time, and after the start of the movement of the train, a strong explosion occurred that damaged the section of the railway track and the car located after the oxygen tank. The glazing of houses located in the area of the railway track was also damaged. Therefore, it is absolutely unacceptable to pour liquid oxygen or work with it in rooms or on sites that have an asphalt surface. Sleepers on the tracks, where draining and filling operations with liquid oxygen are carried out, must be reinforced concrete. The presence of tanks with liquid cryogenic products at industrial sites, and sometimes indoors, creates the prerequisites for the occurrence of serious accidents as a result of spills of liquid cryogenic products or their release to the ground. In world practice, a number of cases with liquid oxygen spills are known, accompanied by very serious consequences. For example, at one of the chemical enterprises, liquid oxygen, due to the lack of consumers, was poured into the ground in significant quantities. Gradually, having soaked the soil, it penetrated to the layers of bituminous waterproofing, the explosion of which led to significant destruction. Measures to prevent such accidents should always be considered when designing air separation plants. Features of handling liquid oxygen should be taken into account when handling liquid air and primary krypton concentrate.
The story of oxygen liquefaction eventually turned into a rivalry. But who will prevail: an engineer who has worked all his life in a metallurgical plant, or a specialist in low-temperature physics at the University of Geneva? Ice or fire, theory or practice, will the Eiffel Tower or the Suez Canal win? Read more about it in the History of Science section.
Liquid oxygen poured into a beaker rather than a Dewar will surprise you with its beautiful blue color. This color is literally sky blue - after all, this gas makes up 21% of air. But the first person to receive it was a down-to-earth engineer and plant owner who was not accustomed to soaring in the sky with dreams.
Louis-Paul Cayette was born in Burgundy, in the picturesque commune of Châtillon-sur-Seine. He began to receive school education there, continued in Paris, and then entered the Mining Institute with his brother Camille. There, in the chemical laboratory, Louis met many future celebrities of the French scientific world. After graduating from the institute, the brothers made several trips to England, Austria and Germany, also for educational purposes: there they saw the most modern blast furnaces and rolling mills, got acquainted with the most advanced equipment. But it was not possible to engage in one science all his life: the father and grandfather of the young people grew old, and at home, in Burgundy, they needed help in working at a metallurgical plant.
Châtillon-sur-Seine
Myrabella / Wikimedia Commons / CC BY-SA 4.0
But even there, Louis did not stop scientific research. He first studied the processes of burning wood in stoves, showing that this process leads to the release of carbon dioxide. He also had a weakness for botany: he devoted his free time to his small greenhouse, where he grew rare orchids and begonias, as a result he even published several articles on plant physiology.
Cayete Orangery
Francois Darbois/Wikipedia
After his brother died of tuberculosis and his father and grandfather died of old age in the 1860s, Louis-Paul Cayeté remained the sole owner of the factory. But this only spurred his research. He took up the study of iron smelting and the participation of various gases in it. To understand the processes in melting furnaces, the scientist needed to measure the temperature and pressure. However, existing instruments did not work in a wide range of temperatures and pressures, and Cayeté devoted a decade and a half of his life to improving manometers and thermometers, as well as to studying the dependence of the volume of gases on pressure and temperature, described by the Boyle-Mariotte law.
Louis Paul Cayette
Wikimedia Commons
In 1870, on the ground floor of the greenhouse, he built himself a laboratory equipped with a powerful hydraulic pump to study chemicals at high pressure and temperature. The result of his work was a manometer capable of measuring pressure up to 400 atmospheres. In 1891, he even installed his pressure gauge on the Eiffel Tower.
Then Kayete became interested in compressing gases and decided to get them in liquid form. In November 1877, he conducted experiments on the liquefaction of acetylene and nitrogen dioxide, first compressing them under high pressure, and then cooling them with other liquefied gases. Caiete used the Joule-Thompson effect, knowing that if you freeze a gas at high pressure and then allow it to expand rapidly, the temperature of the gas will drop even more.
Kayete apparatus for liquefying gases
Popular Science Monthly Volume 12/Wikipedia
But the equipment was imperfect and not perfectly sealed, so the burned gas leaked out. And only by a small cloud in the vessel, he realized that the experiments were crowned with success. Before publishing the results, Kayeté checked to see if impurities in acetylene were causing the formation of a cloud. But, as it turned out, chemically pure acetylene from the best Parisian chemical laboratories behaved in exactly the same way. But it was not difficult to liquefy acetylene, which cannot be said about hydrogen (which, by the way, Kayete will not be able to cope with - his apparatus was unable to cool this gas to the required temperatures, about -200 ° C).
Encouraged by the first success, Louis-Paul Cayeté set to work on the liquefaction of atmospheric gases. He decided to start with oxygen. The scheme of the experiment was similar: first, the scientist brought the pressure in the vessel to 300 atmospheres, then cooled the gas to -29 ° C, and then forced it to expand with the help of sulfur dioxide vapor. And again it turned out to be a cloud of drops condensed as a result of cooling. Cayeté presented his report to the Academy of Sciences on December 24. But there he was overtaken by unpleasant news: it turned out that another scientist had already sent them a telegram about the liquefaction of oxygen two days ago.
Raoul Picket
Wikimedia Commons
This scientist was a physicist from Geneva, Raoul Pictet. He was the third of five offspring of an old Swiss family. Having been educated in Paris, Pictet had already headed a department at the University of Geneva for seven years, working on low-temperature physics. Prior to that, he managed to work in Egypt during the construction of the Suez Canal, reorganizing educational institutions in that country.
Unlike his French rival, he did not practice engineering or applied science himself, although he believed in the importance of education in both fields. Despite this, he undoubtedly had an inventive talent: at the age of 23, he designed a refrigeration unit that produced 15 kilograms of ice per hour. Pictet's idea that there should be a mixture of two substances in refrigeration units was further developed and used in practice in the creation of refrigerators and cryogenic equipment.
Raoul Pictet's laboratory
Ch. Baude / L "Illustration, du 19 janvier 1878, vol. LXXI, p. 45, et L" Exposition de Paris, journal hebdomadaire, du 28 mai 1878, N ° 4, p. 28
The methods for obtaining liquefied oxygen by Cayet and Pictet differed: the Swiss subjected oxygen to compression to 320 atmospheres, cooling it to -140 ° C with the help of vapors of sulfurous and carbonic acids (in fact, sulfur oxides (IV) and carbon dioxide). But, most importantly, both methods worked, and in fact, Kayete's experiments were crowned with success earlier, despite the fact that he took a long time to write his report.
Henri Deville, a French physical chemist who developed an industrial method for the production of aluminum and a teacher at the Sorbonne, helped resolve the dispute. He also introduced the theory of dissociation - the decomposition of a substance when heated - and made the standards of the meter and kilogram from an alloy of platinum and iridium for the International Commission of Weights and Measures in 1872. It was impossible not to listen to such an influential scientist. So which side was he on? It turned out that Deville, a friend of Cayeté, had received a letter from him, dated December 2, with an accurate and complete description of the experiment in obtaining oxygen. When disagreements arose, Henri Deville immediately delivered evidence to the secretary of the Academy of Sciences. So Louis-Paul Cayeté became known as the first scientist to obtain oxygen in liquid form.