Potassium bitartrate

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Potassium bitartrate
Potassium bitartrate sample watchglass.jpg
Potassium bitartrate from the store
Names
IUPAC name
Potassium 2,3,4-trihydroxy-4-oxobutanoate
Other names
Cream of tartar
L(+)-Potassium hydrogen tartrate
Monopotassium tartrate
Potassium (2R,3R)-2,3,4-trihydroxy-4-oxobutanoate
Potassium 3-carboxy-2,3-dihydroxypropanoate
Potassium acid tartrate
Wine diamond
Wine stone
Properties
C4H5O6K
Molar mass 188.177 g/mol
Appearance Colorless crystalline solid
Odor Odorless
Density 1.954 g/cm3
Melting point 172.5 °C (342.5 °F; 445.6 K)
Boiling point 200 °C (392 °F; 473 K) (decomposes)
0.57 g/100 ml (20 °C)
6.1 g/100 ml (100 °C)[1]
Solubility Slightly soluble in alcohol
Vapor pressure ~0 mmHg
Hazards
Safety data sheet Sigma-Aldrich (D-tartrate)
Sigma-Aldrich (L-tartrate)
Flash point 210 °C (410 °F; 483 K)
Lethal dose or concentration (LD, LC):
22,000 mg/kg (rat, oral)
Related compounds
Related compounds
Tartaric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Potassium bitartrate or potassium hydrogen tartrate, more commonly referred to as cream of tartar, is the potassium acid salt of tartaric acid, commonly encountered as byproduct of winemaking. It has the chemical formula C4H5O6K.

Properties

Chemical

The addition of a stronger acid to cream of tartar will yield tartaric acid.

Physical

Cream of tartar is a colorless crystalline solid, soluble in water.

Availability

Potassium bitartrate is sold in many hardware and agricultural stores.

Individual isomers and higher purity potassium hydrogen tartrate can be purchased from chemical suppliers.

Preparation

Can be obtained by neutralizing a solution of tartaric acid with an equimolar solution of potassium hydroxide.

Potassium bitartrate crystallizes in wine casks during the fermentation of grape juice, and can precipitate out of wine in bottles. Several recrystallizations may be required to obtain a very pure product.

Projects

  • Grow beautiful crystals
  • Clean household items
  • pH buffer

Handling

Safety

Potassium bitartrate has low toxicity and it's approved as food additive.

Storage

Potassium bitartrate should be kept in closed bottles. Plastic (PE or PP) or glass bottles are good.

Disposal

No special disposal is required. Discard it as you wish.

References

  1. NOTE: I HAVE FOUND AT LEAST 4 CONTRADICTORY SOLUBILITY DATA FOR THIS COMPOUND; UNTIL THE CORRECT VALUE IS FOUND, THE WIKIPEDIA VALUE IS KEPT

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