Calcium acetate

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Calcium acetate
Calcium acetate.png
Ca-acetate.png
Calcium acetate crystals
Identifiers
Abbreviations Ca(OAc)2
CAS number 62-54-4 YesY, 5743-26-0 (monohydrate) YesY
PubChem 6116
ChemSpider 5890 YesY
UNII Y882YXF34X YesY
EC number 269-613-0
DrugBank DB00258
ChEBI CHEBI:3310 YesY
ChEMBL CHEMBL1200800 N
RTECS number AF7525000
ATC code A12AA12,(anhydrous)
Jmol-3D images Image 1
Properties
Molecular formula C4H6CaO4
Molar mass 158.17 g mol−1
Appearance White solid
hygroscopic
Odor slight acetic acid odor
Density 1.509 g/cm3
Melting point 160 °C (320 °F; 433 K)[1] decomposition to CaCO3 + acetone
Solubility in water 37.4 g/100 mL (0 °C)
34.7 g/100 mL (20 °C)
29.7 g/100 mL (100 °C)
Solubility slightly soluble in methanol, hydrazine
insoluble in acetone, ethanol and benzene
Acidity (pKa) 6.3-9.6
Refractive index (nD) 1.55
Hazards
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Autoignition temperature 680 to 730 °C (1,256 to 1,346 °F; 953 to 1,003 K)
LD50 4280 mg/kg (oral, rat)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

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[edit]

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(l) → Ca(CH3COO)2(l) + H2O(l) + CO2(g)
Ca(OH)2(s) + 2CH3COOH(l) → Ca(CH3COO)2(l) + 2H2O(l)

Since both reagents would have been available pre-historically, the chemical would have been observable as crystals then.

Uses[edit]

  • 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. Side effects of this treatment include upset stomach.[citation needed]
  • Calcium acetate is used as a food additive, as a stabilizer, buffer and sequestrant, mainly in candy products under the number E263. It also neutralizes fluoride in water.[2]
  • Because it is inexpensive, calcium acetate was once a common starting material for the synthesis of acetone before the development of the cumene process:[3][4]
Ca(CH3COO)2 → CaO(s) + CO2(g) + (CH3)2CO(v)
  • A saturated solution of calcium acetate in alcohol forms a semisolid, flammable gel forms that is much like "canned heat" products such as Sterno.[5]
    • Chemistry teachers often prepare "California Snowballs", a mixture of calcium acetate solution and ethanol.[6] The resulting gel is whitish in color, and can be formed to resemble a snowball.

References[edit]

  1. ^ Dale L. Perry (May 19, 2011). Handbook of Inorganic Compounds (Second ed.). Taylor & Francis. p. 84. ISBN 978-1-4398-1461-1. 
  2. ^ Polymeric calcium phosphate cements: setting reaction modifiers
  3. ^ Leo Frank Goodwin and Edward Tyghe Sterne (1920). "Losses Incurred in the Preparation of Acetone by the Distillation of Acetate of Lime.". Industrial & Engineering Chemistry 12 (3): 240–243. doi:10.1021/ie50123a012. 
  4. ^ E. G. R. Ardagh, A. D. Barbour, G. E. McClellan, and E. W. McBride (1924). "Distillation of Acetate of Lime.". Industrial & Engineering Chemistry 16 (11): 1133–1139. doi:10.1021/ie50179a013. 
  5. ^ "Canned Heat" at Journal of Chemical Education "Chemistry comes alive!"
  6. ^ Chemistry Teaching Resources