calcium acetate
{{short description|Chemical compound}}
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 476999801
| ImageFile = Calcium acetate.svg
| ImageSize = 160px
| ImageFile1 = ca-acetate.png
| ImageCaption1 = Calcium acetate crystals
| PIN = Calcium diacetate{{cite book |author=International Union of Pure and Applied Chemistry |date=2014 |title=Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 |publisher=The Royal Society of Chemistry |pages=801 |doi=10.1039/9781849733069 |isbn=978-0-85404-182-4}}
| OtherNames = Acetate of lime
Calcium ethanoate
| Section1 = {{Chembox Identifiers
| Abbreviations = Ca(OAc)2
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 5890
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = Y882YXF34X
| UNII1_Ref = {{fdacite|correct|FDA}}
| UNII1 = 7ZA48GIM5H
| UNII1_Comment = (monohydrate)
| InChIKey = VSGNNIFQASZAOI-NUQVWONBAW
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/2C2H4O2.Ca/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = VSGNNIFQASZAOI-UHFFFAOYSA-L
| CASNo = 62-54-4
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo1 = 5743-26-0
| CASNo1_Ref = {{cascite|correct|CAS}}
| CASNo1_Comment = (monohydrate)
| EINECS = 269-613-0
| ChEMBL_Ref = {{ebicite|changed|EBI}}
| ChEMBL = 1200800
| PubChem = 6116
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB00258
| Beilstein = 3692527
| Gmelin = 22320
| SMILES = CC(=O)O[Ca]OC(=O)C
| SMILES1 = [Ca+2].[O-]C(=O)C.[O-]C(=O)C
| InChI = 1/2C2H4O2.Ca/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2
| RTECS = AF7525000
| MeSHName =
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 3310
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = D00931
}}
| Section2 = {{Chembox Properties
| C=4 | H=6 | O=4 | Ca=1
| MolarMass = 158.166 g/mol (anhydrous)
176.181 g/mol (monohydrate)
| Appearance = White solid
hygroscopic
| Odor = slight acetic acid odor
| Density = 1.509 g/cm3
| MeltingPtC = 160
| MeltingPt_notes = decomposition to CaCO3 + acetone
| BoilingPt =
| BoilingPt_notes =
| Solubility = 37.4 g/100 mL (0 °C)
34.7 g/100 mL (20 °C)
29.7 g/100 mL (100 °C)
| SolubleOther = slightly soluble in methanol, hydrazine
insoluble in acetone, ethanol and benzene
| pKa = ca. 0.7
| pKb =
| RefractIndex = 1.55
| MagSus = −70.7·10−6 cm3/mol
}}
| Section3 = {{Chembox Structure
| CrystalStruct =
| Coordination =
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| Section5 = {{Chembox Thermochemistry
| DeltaHf =
| DeltaHc =
| Entropy =
| HeatCapacity = }}
| Section6 = {{Chembox Pharmacology
| ATCCode_prefix = V03
| ATCCode_suffix = AE07
| ATC_Supplemental =
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| Metabolism =
| HalfLife =
| ProteinBound =
| Excretion =
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| Section4 = {{Chembox Explosive
| ShockSens =
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| Section7 = {{Chembox Hazards
| MainHazards =
| NFPA-H = 1
| NFPA-F = 1
| NFPA-R = 0
| NFPA-S =
| FlashPt =
| AutoignitionPtC = 680 to 730
| ExploLimits =
| LD50 = 4280 mg/kg (oral, rat)
| PEL = }}
| Section8 = {{Chembox Related
| OtherAnions =
| OtherCations = Magnesium acetate
| OtherFunction =
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| OtherCompounds = }}
}}
Calcium acetate is a chemical compound which is a calcium salt of acetic acid. It has the formula Ca(C2H3O2)2. Its standard name is calcium acetate, while calcium ethanoate is the systematic name. An older name is acetate of lime. The anhydrous form is very hygroscopic; therefore the monohydrate (Ca(CH3COO)2•H2O) is the common form.
Production
Calcium acetate can be prepared by soaking calcium carbonate (found in eggshells, or in common carbonate rocks such as limestone or marble) or hydrated lime in vinegar:
:CaCO3(s) + 2CH3COOH(aq) → Ca(CH3COO)2(aq) + H2O(l) + CO2(g)
:Ca(OH)2(s) + 2CH3COOH(aq) → Ca(CH3COO)2(aq) + 2H2O(l)
Since both reagents would have been available pre-historically, the chemical would have been observable as crystals then.
Uses
- In kidney disease, blood levels of phosphate may rise (called hyperphosphatemia) leading to bone problems. Calcium acetate binds phosphate in the diet to lower blood phosphate levels.{{cite web |title=Calcium Acetate |url=https://www.mayoclinic.org/drugs-supplements/calcium-acetate-oral-route/description/drg-20062494 |website=Mayo Clinic |access-date=19 November 2019}}
- Calcium acetate is used as a food additive, as a stabilizer, buffer and sequestrant, mainly in candy products under the number E263.
- Tofu is traditionally obtained by coagulating soy milk with calcium sulfate. Calcium acetate has been found to be a better alternative; being soluble, it requires less skill and a smaller amount.{{cite journal | doi = 10.1111/j.1365-2621.1980.tb03864.x | title = Use of Calcium Salts for Soybean Curd Preparation | date = 1980 | last1 = Lu | first1 = J. Y. | last2 = Carter | first2 = Eloise | last3 = Chung | first3 = R. A. | journal = Journal of Food Science | volume = 45 | pages = 32–34 }}
- Because it is inexpensive, calcium acetate was once a common starting material for the synthesis of acetone before the development of the cumene process:{{cite journal
| title = Losses Incurred in the Preparation of Acetone by the Distillation of Acetate of Lime.
|author1=Leo Frank Goodwin |author2=Edward Tyghe Sterne | journal = Industrial & Engineering Chemistry
| volume = 12
| issue = 3
| year = 1920
| pages = 240–243
| doi = 10.1021/ie50123a012 |url=https://zenodo.org/record/1428748 }}{{cite journal
| title = Distillation of Acetate of Lime.
|author1=E. G. R. Ardagh |author2=A. D. Barbour |author3=G. E. McClellan |author4=E. W. McBride | journal = Industrial & Engineering Chemistry
| volume = 16
| issue = 11
| year = 1924
| pages = 1133–1139
| doi = 10.1021/ie50179a013 }}
: Ca(CH3COO)2 → CaCO3(s) + (CH3)2CO
- A saturated solution of calcium acetate in alcohol forms a semisolid, flammable gel that is much like "canned heat" products such as Sterno.{{Cite web |url=http://jchemed.chem.wisc.edu/jcesoft/CCA/CCA3/MAIN/CANHEAT/PAGE1.HTM |title="Canned Heat" at Journal of Chemical Education "Chemistry comes alive!" |access-date=2008-03-26 |archive-date=2008-10-03 |archive-url=https://web.archive.org/web/20081003142048/http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA3/MAIN/CANHEAT/PAGE1.HTM |url-status=dead }} Chemistry teachers often prepare "California Snowballs", a mixture of calcium acetate solution and ethanol.{{cite web |url=http://umanitoba.ca/outreach/crystal/chemistry.html |title=Chemistry Teaching Resources |archive-url=https://web.archive.org/web/20110923051746/https://umanitoba.ca/outreach/crystal/chemistry.html |archive-date=2011-09-23 |url-status=dead |website=University of Manitoba}} The resulting gel is whitish in color, resembling a snowball and can be lit on fire; it will burn for around 20 minutes.{{cite web |title=CA (California) Snowball |url=https://chem.libretexts.org/Courses/University_of_California_Davis/UCDemos/CA_(California)_Snowball |website=LibreTexts |publisher=University of California Davis |access-date=2024-12-31}}
Natural occurrence
Pure calcium acetate is yet unknown among minerals. {{nowrap|Calclacite{{mdash}}}}calcium acetate chloride {{nowrap|pentahydrate{{mdash}}}}is listed as a known mineral,{{Cite web |url=http://www.mindat.org/min-862.html |title=Calclacite |access-date=2024-12-31 |archive-date=2017-01-20 |archive-url=https://web.archive.org/web/20170120095111/http://www.mindat.org/min-862.html |url-status=live |website=mindat.org}} but its genesis is anthropogenic (human-generated, as opposed to naturally occurring).{{cite web |title=Man made minerals |url=https://australian.museum/learn/minerals/what-are-minerals/man-made-minerals/ |website=The Australian Museum |publisher=New South Wales Government |date=2022-12-08 |quote=It [calclacite] owes its existence to humans – it only grows naturally in old oak drawers as it forms when calcium-rich rocks or fossils react with acetic acid in the wood.}}
References
{{Drugs for treatment of hyperkalemia and hyperphosphatemia}}
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{{Acetates}}{{Calcium compounds}}