Carbon monoxide

carbon monoxide, also called carbon(II) oxide, carbonaceous gas and carbonaceous anhydride (the last two are increasingly in disuse), whose chemical formula CO is a colorless and highly toxic gas. Can cause death when breathed in high levels. It is produced by the deficient combustion of substances such as gas, gasoline, kerosene, coal, oil, tobacco or wood. Fireplaces, furnaces, water heaters or space heaters, and fuel-burning household appliances such as kitchen stoves or burners or kerosene heaters can also do it if they aren't working properly. Vehicles with the engine running also expel it. Large amounts of CO are formed as a by-product during oxidative processes for the production of chemicals, making purification of waste gases necessary. On the other hand, considerable research efforts are being made to develop new processes and catalysts for the maximization of the production of the useful product. It can also be found in the atmospheres of carbon stars.

History

Prehistory

Humans have had a complex relationship with carbon monoxide since learning to control fire around 800,000 B.C. The first humans probably discovered the toxicity of carbon monoxide poisoning by introducing fire into their dwellings. The early development of metallurgy and foundry technologies, which emerged around 6000 B.C. until the Bronze Age, it also affected humanity from exposure to carbon monoxide. Aside from carbon monoxide toxicity, Native American Indians may have experienced the neuroactive properties of carbon monoxide through shamanic fireside rituals.

Ancient history

Early civilizations developed mythological accounts to explain the origin of fire, such as Prometheus from Greek mythology who shared fire with humans. Aristotle (384-322 B.C.) was the first to record that burning coals produced toxic fumes. The Greek physician Galen (AD 129-199) speculated that there was a change in the composition of air that caused harm when inhaled, and many others of the time developed a knowledge base of carbon monoxide in the context of the toxicity of coal fumes. Cleopatra may have died from carbon monoxide poisoning.

Pre-industrial Revolution

Georg Ernst Stahl mentioned carbonarii halitus in 1697 in reference to toxic fumes believed to be carbon monoxide. Friedrich Hoffmann conducted the first modern scientific research on carbon monoxide poisoning from coal in 1716. Herman Boerhaave conducted the first scientific experiments on the effect of carbon monoxide (vapours from coal) on animals in the 1730s.

Joseph Priestley is considered to have first synthesized carbon monoxide in 1772. Carl Wilhelm Scheele similarly isolated carbon monoxide from charcoal in 1773 and thought it might be the carbonic entity that made the fumes toxic. Torbern Bergman isolated carbon monoxide from oxalic acid in 1775. Later, in 1776, the French chemist fr produced CO by heating zinc oxide with coke, but wrongly concluded that the gaseous product was hydrogen, since it burned with a flame blue. In the presence of oxygen, including atmospheric concentrations, carbon monoxide burns with a blue flame, producing carbon dioxide. Inconclusive experiments similar to Lassone's in 1777 were performed by Antoine Lavoisier. The gas was identified as a compound containing carbon and oxygen by William Cruickshank in 1800.

Thomas Beddoes and James Watt recognized carbon monoxide (as hydrocarbonate) to clear venous blood in 1793. Watt suggested that coal fumes might act as an antidote to oxygen in the blood, and Beddoes and Watt similarly suggested that hydrocarbonate has a higher affinity for animal fiber than oxygen in 1796. In 1854, Adrien Chenot similarly suggested carbon monoxide to remove oxygen from the blood and then be oxidized by the body to carbon dioxide. The mechanism for carbon monoxide poisoning is widely credited to Claude Bernard whose memoirs beginning in 1846 and published in 1857 phrase, 'prevents arterial blood from becoming venous'. Felix Hoppe-Seyler independently published similar findings the following year.

Advent of industrial chemistry

Carbon monoxide was recognized as a highly valuable reagent in the 1900s. Three industrial processes illustrate its evolution in industry. In the Fischer-Tropsch process, coal and other carbon-rich feedstocks are converted to liquid fuels via CO. This technology, originally developed in Germany during the war to make up for the lack of domestic oil, is still in use today. Also in Germany, a mixture of CO and hydrogen was found to combine with alkene to give aldehydes. This process, called hydroformylation, is used to produce many chemicals on a large scale, such as surfactants, as well as specialty compounds that are popular pharmaceuticals and fragrances. For example, CO is used in the production of vitamin A. In a third important process, attributed to Monsanto researchers, CO is combined with methanol to give acetic acid. Most of the acetic acid is produced by the Cativa process. Hydroformylation and the synthesis of acetic acid are two of the innumerable carbonylation processes.

Physical and chemical properties

Carbon monoxide is the simplest oxocarbon and is isoelectronic with other diatomic triple bond species possessing 10 valence electrons, including cyanide anion, nitrosonium cation, boron monofluoride, and molecular nitrogen. It has a molar mass of 28.0, which, according to the ideal gas law, makes it slightly less dense than air, which has an average molar mass of 28.8. | Carbon and oxygen are linked by a triple bond made up of two net pi bonds and one sigma bond. The bond length between the carbon atom and the oxygen atom is 112.8 pm. This bond length is consistent with a triple bond, as in molecular nitrogen (N₂), which has a similar bond length (109.76 pm) and nearly the same molecular mass. The carbon-oxygen double bonds are significantly longer, 120.8 pm. in formaldehyde, for example. The boiling point (82 K) and melting point (68 K) are very similar to those of N₂ (77 K and 63 K, respectively). The bond dissociation energy of 1072 kJ/mol is higher than that of N₂ (942 kJ/mol) and represents the strongest known chemical bond.

The electronic ground state of carbon monoxide is a singlet state since there are no unpaired electrons.

Poisoning

Carbon monoxide indicator in a garage.

If breathed in, even in moderate amounts, carbon monoxide can cause death by poisoning in a few minutes because it replaces oxygen in the hemoglobin in the blood. It has an affinity for heme 250 times greater than oxygen.

Carboxyhemoglobin, a product formed, cannot transport oxygen; Furthermore, the presence of this compound interferes with the dissociation of oxygen from the remaining oxyhemoglobin, thus hindering the transfer of oxygen to the tissues.

Once you have breathed a fairly large amount of carbon monoxide (having 75% of hemoglobin with carbon monoxide) the only way to survive is by breathing pure oxygen. Every year a large number of people lose their lives accidentally due to poisoning with this gas. Pregnant women and their fetuses, young children, the elderly, and those with anemia, heart or respiratory problems may be much more sensitive to carbon monoxide.

Normal nonsmoking adults are estimated to have carboxyhemoglobin levels less than 1% saturation; that is, 1% of hemoglobin is bound to carbon monoxide. This figure has been attributed to the endogenous formation of CO. Smokers can have a saturation of 5 to 10%, depending on the intensity of their smoking. A person breathing air with 0.1% CO (1000 ppm) has a carboxyhemoglobin level of 50%.

Treatment consists of moving the person away from the source of exposure, and taking measures to ensure their breathing. Oxygen functions as a specific CO antagonist and for that reason is given as a treatment. The half-life of CO in the blood is 320 minutes; with pure oxygen it is reduced to 80 minutes and with hyperbaric oxygen (2 or 3 atmospheres) it can be reduced to 20 minutes.

Combustion of CO

The combustion of CO is given by the following equation:

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