Calcium acetate

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.

Calcium acetate

Calcium acetate crystals
Names
Preferred IUPAC name Calcium diacetate[1]
Other names Acetate of lime Calcium ethanoate
Identifiers
CAS Number	62-54-4 Y 5743-26-0 (monohydrate) Y
3D model (JSmol)	Interactive image Interactive image
Abbreviations	Ca(OAc)2
Beilstein Reference	3692527
ChEBI	CHEBI:3310 Y
ChEMBL	ChEMBL1200800 N
ChemSpider	5890 Y
DrugBank	DB00258 Y
ECHA InfoCard	100.000.492
EC Number	269-613-0
E number	E263 (preservatives)
Gmelin Reference	22320
KEGG	D00931 Y
PubChem CID	6116
RTECS number	AF7525000
UNII	Y882YXF34X Y 7ZA48GIM5H (monohydrate) Y
CompTox Dashboard (EPA)	DTXSID0020234
InChI InChI=1S/2C2H4O2.Ca/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2 Y Key: VSGNNIFQASZAOI-UHFFFAOYSA-L Y InChI=1/2C2H4O2.Ca/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2 Key: VSGNNIFQASZAOI-NUQVWONBAW
SMILES CC(=O)O[Ca]OC(=O)C [Ca+2].[O-]C(=O)C.[O-]C(=O)C
Properties
Chemical formula	C4H6CaO4
Molar mass	158.166 g/mol (anhydrous) 176.181 g/mol (monohydrate)
Appearance	White solid hygroscopic
Odor	slight acetic acid odor
Density	1.509 g/cm3
Melting point	160 °C (320 °F; 433 K)[2] 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)	ca. 0.7
Magnetic susceptibility (χ)	−70.7·10−6 cm3/mol
Refractive index (nD)	1.55
Pharmacology
ATC code	V03AE07 (WHO)
Hazards
NFPA 704 (fire diamond)	1 1 0
Autoignition temperature	680 to 730 °C (1,256 to 1,346 °F; 953 to 1,003 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	4280 mg/kg (oral, rat)
Related compounds
Other cations	Magnesium acetate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

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.^[3]
• 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.^[4]
• Because it is inexpensive, calcium acetate was once a common starting material for the synthesis of acetone before the development of the cumene process:^[5][6]

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.^[7] Chemistry teachers often prepare "California Snowballs", a mixture of calcium acetate solution and ethanol.^[8] The resulting gel is whitish in color, resembling a snowball and can be lit on fire; it will burn for around 20 minutes.^[9]

Natural occurrence

Pure calcium acetate is yet unknown among minerals. Calclacite—calcium acetate chloride pentahydrate—is listed as a known mineral,^[10] but its genesis is anthropogenic (human-generated, as opposed to naturally occurring).^[11]