Calcium bisulfite

Calcium bisulfite (calcium bisulphite or calcium hydrogen sulfite) is an inorganic compound which is the salt of a calcium cation and a bisulfite anion. It may be prepared by treating lime with an excess of sulfur dioxide and water. As a food additive it is used as a preservative under the E number E227. Calcium bisulfite is an acid salt and behaves like an acid in aqueous solution. It is used in the sulfite process for producing paper from wood chips.[1]

Calcium bisulfite
Names
IUPAC name
Calcium hydrogen sulfite
Other names
Calcium bisulphite
E227
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.034.007
E number E227 (preservatives)
RTECS number
  • EV9294500
UNII
  • InChI=1S/Ca.2H2O3S/c;2*1-4(2)3/h;2*(H2,1,2,3)/q+2;;/p-2 checkY
    Key: LVGQIQHJMRUCRM-UHFFFAOYSA-L checkY
  • InChI=1/Ca.2H2O3S/c;2*1-4(2)3/h;2*(H2,1,2,3)/q+2;;/p-2
    Key: LVGQIQHJMRUCRM-NUQVWONBAX
  • OS(=O)[O-].OS(=O)[O-].[Ca+2]
Properties
Ca(HSO3)2
Molar mass 202.22 g/mol
Melting point 203 °C
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Synthesis

It may be prepared by treating lime (chemical formula Ca(OH)₂) with an excess of sulfur dioxide and water. [2]

Upon synthesis of calcium bisulfite solution, it will have a green to yellow opaque appearance as an aqueous solution.[3]

Chemical Reactions

When calcium bisulfite reacts with the surrounding air, a crystalline precipitate will form composed of calcium sulfite dihydrate.

When calcium bisulfite is digested as a food additive, different reactions in metabolic pathways can result. One common pathway results in a reaction that will yield 6%-8% sulfur dioxide. This can go to sulfite when absorbed by the lungs, and the sulfite will be converted to sulfate in the liver by an enzyme called sulfite oxidase. Sulfite can be harmful for people susceptible to asthma, leading to asthma attacks. Sulfite can also cause uticaria and angioedema in otherwise healthy individuals. [3]

A process known as wet limestone scrubbing is a means by which sulfur dioxide is removed from the waste emmitted during the combustion of fossil fuels. A step in this process is the oxidation of calcium bisulfite to produce sulfate. When this reaction occurs in an aqeous solution, gyspum results. The rate of this reaction can be increased in the presence of Magnesium (II) Sulfate as a catalyst. [4]

Other catalysts for the oxidation of calcium bisulfite include Manganese, Iron, Cobalt, Nickel, Lead, and Zinc. [2]

Application

Economical

Calcium bisulfite is one of the chemicals used in an overal Mild Bisulfite treatment meant to increase the sugar yield effieciency in processing timber excess to biofuel and jet fuel. The use of the Mild Bisulfite methodology both increases the yield and also saves cost in shipping wood to ethanol plants for processing [5]

Calcium bisulfite is often used as a food preservative. One such case is to brine cherries. However, research is showing that some microorganisms can cause cherries to rot since they produce the enzyme polygalacturonase that can work even in the presence of calcium bisulfite. Three species of fungi that are especially capable of rotting brined cherries are Aspergillus niger, Cytospora leucostoma, and Penicillium expansum. [6]

Medicinal

A calcium bisulfite liquor solution is used in the process of converting dihydroquercetin in tree bark pulp and then converting dihydroquercetin to a usable form: quercetin. Calcium bisulfite is not the optimum bisulfite compound for this reaction since the calcium ions can be removed from the calcium bisulfite solution during the reaction, thereby inhibiting the mechanism. However, calcium bisulfites, like other bisuflites such as ammonium bisulfite, have a catalytic capacity in this reaction since they are not used up and can be reused. [7]

See also

References
  1. Patt, Rudolf; Kordsachia, Othar; Süttinger, Richard; Ohtani, Yoshito; Hoesch, Jochen F.; Ehrler, Peter; Eichinger, Rudolf; Holik, Herbert; Hamm (2000). "Paper and Pulp". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a18_545.
  2. Karatza, Despina; Prisciandaro, Marina; Lancia, Amedeo; Musmarra, Dino (2010-06-01). "Sulfite Oxidation Catalyzed by Cobalt Ions in Flue Gas Desulfurization Processes". Journal of the Air & Waste Management Association. 60 (6): 675–680. doi:10.3155/1047-3289.60.6.675. ISSN 1096-2247. PMID 20564992. S2CID 9127556.
  3. EFSA Panel on Food additives and Nutrient Sources added to Food (ANS) (2016). "Scientific Opinion on the re-evaluation of sulfur dioxide (E 220), sodium sulfite (E 221), sodium bisulfite (E 222), sodium metabisulfite (E 223), potassium metabisulfite (E 224), calcium sulfite (E 226), calcium bisulfite (E 227) and potassium bisulfite (E 228) as food additives". EFSA Journal. 14 (4). doi:10.2903/j.efsa.2016.4438 – via wiley.com.
  4. Lancia, Amedeo; Musmarra, Dino; Prisciandaro, Marina; Tammaro, Marco (1999-07-01). "Catalytic oxidation of calcium bisulfite in the wet limestone–gypsum flue gas desulfurization process". Chemical Engineering Science. 54 (15): 3019–3026. Bibcode:1999ChEnS..54.3019L. doi:10.1016/S0009-2509(98)00483-7. ISSN 0009-2509.
  5. Dwight Anderson and, Johnway Gao (2015). "Mild Bisulfite Pretreatment of Forest Residuals" (PDF).
  6. Lewis JC, Pierson CF, Powers MJ (1963). "Fungi Associated with Softening of Bisulfite-Brined Cherries". Applied and Environmental Microbiology. 11 (2): 93–99. doi:10.1128/am.11.2.93-99.1963. PMC 1057949. PMID 16349630. S2CID 9370969 – via ASM Journals.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. Kurth, Ervin (1953). "Quercetin from Fir and Pine Bark". Industrial & Engineering Chemistry. 45 (9): 2096–2097. doi:10.1021/ie50525a047. Retrieved 2023-03-29.
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