Calcium acetate is a chemical compound which is a calciumsalt 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 can be prepared by soaking calcium carbonate (found in eggshells, or in common carbonate rocks such as limestone or marble) in vinegar:
CaCO3 + 2CH3COOH → Ca(CH3COO)2 + H2O + CO2
Since both reagents would have been available pre-historically, the chemical would have been observable as crystals then.
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.
Calcium acetate is used as a food additive, as a stabilizer, buffer and sequestrant, mainly in candy products. It also neutralizes fluoride in water.
Because it is inexpensive, calcium acetate was once a common starting material for the synthesis of acetone before the development of the cumene process.
A saturated solution of calcium acetate in alcohol forms a semisolid, flammable gel forms that is much like "canned heat" products such as Sterno.
Chemistry teachers often prepare "California Snowballs", a mixture of calcium acetate solution and ethanol. The resulting gel is whitish in color, and can be formed to resemble a snowball.
^Leo Frank Goodwin and Edward Tyghe Sterne (1920). "Losses Incurred in the Preparation of Acetone by the Distillation of Acetate of Lime.". Industrial & Engineering Chemistry12 (3): 240–243. doi:10.1021/ie50123a012.
^E. G. R. Ardagh, A. D. Barbour, G. E. McClellan, and E. W. McBride (1924). "Distillation of Acetate of Lime.". Industrial & Engineering Chemistry16 (11): 1133–1139. doi:10.1021/ie50179a013.