Calcium acetate

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Calcium acetate
Calcium acetate dried by NileRed.jpg
Calcium acetate obtained from TUMS, dried
Names
IUPAC name
Calcium acetate
Other names
Acetate of lime
Calcium(II) acetate
Calcium diacetate
Calcium ethanoate
Lime acetate
Lime pyrolignite
Properties
CaC4H6O4
Ca(CH3COO)2
Ca(OAc)2
Molar mass 158.17 g/mol
Appearance Colorless to white hygroscopic crystals
Odor Slight acetic acid odor
Density 1.509 g/cm3
Melting point 160 °C (320 °F; 433 K) (decomposes)
Boiling point Decomposes
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, benzene, toluene
Acidity (pKa) 6.3-9.6
Hazards
Safety data sheet Macron Fine Chemicals
Lethal dose or concentration (LD, LC):
4280 mg/kg (oral, rat)
Related compounds
Related compounds
Sodium acetate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Calcium acetate is a water soluble acetate of calcium. It has a usefully interesting solubility curve, and can be very easily be made into a supersaturated solution.

Properties

Chemical

Calcium acetate can be easily cracked on heating to make acetone and calcium carbonate.

Ca(CH3COO)2 → (CH3)2CO + CaCO3

It is also a rather reactive, soluble calcium salt. Treatment of anhydrous calcium acetate with concentrated sulfuric acid produces insoluble calcium sulfate and glacial acetic acid, a useful reagent. Calcium acetate will also gel many alcohols if mixed in correct proportions. Too much calcium acetate will revert the gel back to a liquid.

Physical

Calcium acetate in pure form is a white powder that readily absorbs water to form a translucent, crystalline monohydrate. It can be redried to the anhydrous form with heating, but calcium acetate is one of few ionic salts that can burn on its own, so open flames and very high temperatures will ruin the product.

Availability

Not only is this chemical commonly sold as a 'hot ice' substitute, it can be made from calcium carbonate or calcium hydroxide and acetic acid. Avoid using calcium oxide (quicklime) as the neutralization reaction is too exothermic and the mixture may boil.

2 CH3COOH + CaCO3 → Ca(CH3COO)2 + H2O + CO2
2 CH3COOH + Ca(OH)2 → Ca(CH3COO)2 + 2 H2O

Preparation

Calcium acetate can be easily produced by reaction of calcium hydroxide or carbonate with acetic acid.

Projects

Handling

Safety

Calcium acetate can be considered mostly harmless. It is, though, a soluble calcium salt, and large oral doses could be harmful.

Storage

Calcium acetate should be stored in sealed bottles, to keep in anhydrous. The hydrated form can be stored in any bottle or container.

Disposal

As it has low toxicity, it can be safely poured down the drain or dumped in the trash.

References

Relevant Sciencemadness threads