Pyruvic acid

From Sciencemadness Wiki
Jump to: navigation, search
Pyruvic acid
Names
IUPAC name
2-Oxopropanoic acid
Preferred IUPAC name
2-Oxopropanoic acid
Systematic IUPAC name
2-Oxopropanoic acid
Other names
Acetylformic acid
Pyroracemic acid
α-Ketopropionic acid
Properties
C3H4O3
CH3COCOOH
Molar mass 88.06 g/mol
Appearance Colorless liquid
Odor Sour vinegar-like
Density 1.250 g/cm3 (20 °C)
1.267 g/cm3 (25 °C)
Melting point 11.8–12 °C (53.2–53.6 °F; 284.9–285.1 K)
Boiling point 165 °C (329 °F; 438 K)
Miscible
Solubility Reacts with amines, bases
Miscible with alcohols, carboxylic acids, ketones
Vapor pressure 1.29 mmHg
Acidity (pKa) 2.50
Hazards
Safety data sheet Sigma-Aldrich
Related compounds
Related compounds
Lactic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Pyruvic acid is the simplest of the keto acids, as well as alpha-keto acids, which are compounds with a carboxylic acid and a ketone functional group. It has the formula CH3C(=O)COOH.

Pyruvic acid is an important compound in the biological metabolism, by supplying energy to cells through the Krebs cycle.

Properties

Chemical

Pyruvic acid is a mid-strength carboxylic acid. It reacts with bases to form salts, called pyruvates.

Pyruvic acid supplies energy to cells through the citric acid cycle (also known as the Krebs cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactate when oxygen is lacking (lactic acid).

Physical

Pyruvic acid is a colorless to slightly yellowish colored liquid, with a sour vinegar-like odor. It is miscible with water and other organic solvents. Due to its melting point of around 11 °C, the pure compound will solidify in cold weather or if placed in a fridge.

Availability

Pyruvic acid is sold by chemical suppliers.

Pyruvates, such as calcium pyruvate, are sold as weight loss supplements. The free acid can be obtained by reacting the pyruvate salt with a strong acid, then distill the free acid under reduced pressure.

Preparation

Pyruvic acid may be prepared by heating a mixture of tartaric acid and potassium bisulfate. The crude distillate is further purified by distilling it under reduced pressure.

Oxidation of lactic acid will produce pyruvic acid. Hydroxyacetone can also be used.

Alternatively, it can be obtained from the oxidation of propylene glycol with a strong oxidizer (e.g., potassium permanganate, sodium hypochlorite/bleach):

CH3CH(OH)CH2(OH) + [O] → CH3C(=O)COOH

A less common route involves hydrolysis of acetyl cyanide, formed by reaction of acetyl chloride with potassium cyanide:

CH3COCl + KCN → CH3COCN + KCl
CH3COCN → CH3C(=O)COOH

Pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through a reaction with acetyl-CoA.

Projects

  • Make pyruvates
  • Make lactic acid

Handling

Safety

Pure pyruvic acid is somewhat corrosive and irritant to skin, nose, mouth and eyes. The acid and its salts display little toxicity.

Consumption of excess pyruvates will lead to diarrhea, bloating, gas and increase in low-density lipoprotein (LDL) cholesterol.

Storage

In closed air-tight bottles.

Disposal

No special disposal is required. Discard it was you with.

References

Relevant Sciencemadness threads