Calcium Acetate
Properties
| State | Solid (white hygroscopic powder or crystals) |
| Color | White |
| Solubility | Very soluble in water (347 g/L at 20°C); slightly soluble in ethanol |
| Melting Point | 160°C (monohydrate decomposes) |
| Boiling Point | Decomposes before boiling |
About Calcium Acetate
Calcium acetate is the calcium salt of acetic acid, and it sits at an interesting crossroads of pharmacology, food chemistry, and the history of organic synthesis. The chemistry that matters: Ca(C2H3O2)2 dissolves in water at about 347 g/L without needing the acidic stomach environment that calcium carbonate requires, which is why it is preferred over CaCO3 as a phosphate binder in dialysis patients. In the gut, the released Ca²⁺ ion grabs dietary phosphate (PO4³⁻) and precipitates as insoluble calcium phosphate, which then leaves the body unabsorbed — the mechanism of action behind the brand name PhosLo. The pyrolysis chemistry is the historically interesting part. Heat dry calcium acetate to roughly 400 °C and it decarboxylates and rearranges to give acetone and calcium carbonate: Ca(CH3COO)2 → CaCO3 + CH3COCH3. From the 1860s through the early 20th century this was how the world made acetone, until the cumene-from-propylene route quietly displaced it. The compound is also a buffer (pKa of acetic acid is 4.76), which is why it shows up in food technology as E263 — it controls pH in baked goods and processed cheese.
Where you'll encounter it
If you work in nephrology or pharmacy you encounter calcium acetate as PhosLo tablets — patients with end-stage renal disease take them with meals to keep serum phosphate from climbing into the range that drives vascular calcification. In a food-processing plant, it is the white powder added to control acidity in baked goods or sequester metal ions that would otherwise catalyze rancidity. Brewers and cheesemakers use it to tweak water hardness. Around the lab, you see it occasionally as a calcium source for assays where chloride or sulfate would interfere, and once in a while as a starting material for niche organic-synthesis demos that retrace the dry-distillation route to acetone.
Common Uses
- Phosphate binder in dialysis patients with end-stage renal disease (PhosLo)
- Food sequestrant and buffer (E263) in baked goods and processed cheese
- Calcium magnesium acetate alternative for environmentally sensitive road de-icing
- Starting material in the historical dry-distillation route to acetone
- Calcium source for biochemical assays where Cl⁻ or SO4²⁻ would interfere
- Stabilizer to suppress recrystallization in some confectionery and dairy products
- Cheesemaking adjunct to firm curd and adjust calcium balance
Safety Information
Food-grade calcium acetate is GRAS at typical use concentrations and not classified hazardous under GHS. The clinically meaningful risk is hypercalcemia in PhosLo patients — serum Ca should be monitored, and patients are kept under roughly 1.5 g elemental Ca per day from binders. Bulk powder is mildly irritating to eyes (H319-like) and the respiratory tract on inhalation; gloves and a dust mask handle it adequately. No significant fire or reactivity hazard.
This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals.