Английская Википедия:Carbonation
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Carbonation is the chemical reaction of carbon dioxide to give carbonates, bicarbonates, and carbonic acid.[1] In chemistry, the term is sometimes used in place of carboxylation, which refers to the formation of carboxylic acids.
In inorganic chemistry and geology, carbonation is common. Metal hydroxides (MOH) and metal oxides (M'O) react with CO2 to give bicarbonates and carbonates:
- MOH + CO2 → M(HCO3)
- M'O + CO2 → M'CO3
Selected carbonations
Carbonic anhydrase
In mammalian physiology, transport of carbon dioxide to the lungs involves a carbonation reaction catalyzed by the enzyme carbonic anhydrase. In the absence of such catalysts, carbon dioxide cannot be expelled sufficient rate to support metabolic needs. The enzyme harbors a zinc aquo complex, which captures carbon dioxide to give a zinc bicarbonate:[2]
Behavior of concrete
In reinforced concrete, the chemical reaction between carbon dioxide In the air and calcium hydroxide and hydrated calcium silicate in the concrete is known as neutralisation. The similar reaction in which calcium hydroxide from cement reacts with carbon dioxide and forms insoluble calcium carbonate is carbonatation.
Urea production
Carbonation of ammonia is one step in the industrial production of urea:In 2020, worldwide production capacity was approximately 180 million tonnes.[3] As a fertilizer, it is a source of nitrogen for plants. Urea production plants are almost always located adjacent to the site where the ammonia is manufactured.[4]
In the subsequent urea conversion: the ammonium carbamate is decomposed into urea, releasing water:
Solubility
Henry's law states that PШаблон:CO2=KBxШаблон:CO2 where PШаблон:CO2 is the partial pressure of Шаблон:CO2 gas above the solution. KB is Henry's law constant. KB increases as temperature increases. xШаблон:CO2 is the mole fraction of Шаблон:CO2 gas in the solution. According to Henry's law carbonation increases in a solution as temperature decreases.[5]
Since carbonation is the process of giving compounds like carbonic acid (liq) from CO2 (gas) {i.e. making liquid from gasses} thus the partial pressure of CO2 has to decrease or the mole fraction of CO2 in solution has to increase {PШаблон:CO2/xШаблон:CO2 = KB} and both these two conditions support increase in carbonation.
References
- ↑ "Impregnation or treatment with carbon dioxide; conversion into a carbonate."Шаблон:Cite book
- ↑ Шаблон:Cite journal
- ↑ Шаблон:Cite web
- ↑ Шаблон:Ullmann
- ↑ Шаблон:Cite web
