Title: Pyruvic Acid
CAS Registry Number: 127-17-3
CAS Name: 2-Oxopropanoic acid
Additional Names: a-ketopropionic acid; acetylformic acid; pyroracemic acid; brenztraubensäure (German)
Molecular Formula: C3H4O3
Molecular Weight: 88.06
Percent Composition: C 40.92%, H 4.58%, O 54.51%
Line Formula: CH3COCOOH
Literature References: Intermediate in sugar metabolism and in enzymatic carbohydrate degradation (alcoholic fermentation) where it is converted to acetaldehyde and CO2 by carboxylase, see Nord, Chem. Rev. 26, 423 (1940). In muscle, pyruvic acid (derived from glycogen) is reduced to lactic acid during exertion, which is reoxidized and partially retransformed to glycogen during rest. The liver can convert pyruvic acid to alanine by amination. Pyruvic acid has been isolated from cane sugar fermentation broth by fixation with b-naphthylamine giving a-methyl-b-naphthocinchonic acid: Grab, Biochem. Z. 123, 84 (1921). The most practical method of preparing pyruvic acid is by distillation of tartaric acid in presence of potassium acid sulfate as dehydrating agent. The distillate must be fractionated under reduced pressure: Erlenmeyer, Ber. 14, 321 (1881); Döbner, Ann. 242, 269 (1887); Howard, Fraser, Org. Synth. coll. vol. I (2nd ed., 1941) p 475.
Properties: Liquid. Odor resembling that of acetic acid. d415 1.267; mp 11.8°; bp760 165° (dec); bp100 106.5°; bp40 85.3°; bp20 70.8°; bp10 57.9°; bp5 45.8°; bp1.0 21.4°; nD20 1.4138. Absorption spectrum: Henri, Fromageot, Bull. Soc. Chim. [4] 37, 846 (1925). pK (25°) 2.49. Miscible with water, alcohol, ether. Polymerizes and dec on standing unless pure and kept in container with airtight closure.
Melting point: mp 11.8°
Boiling point: bp760 165° (dec); bp100 106.5°; bp40 85.3°; bp20 70.8°; bp10 57.9°; bp5 45.8°; bp1.0 21.4°
pKa: pK (25°) 2.49
Index of refraction: nD20 1.4138
Density: d415 1.267
Derivative Type: Methyl ester
Molecular Formula: C4H6O3
Molecular Weight: 102.09
Percent Composition: C 47.06%, H 5.92%, O 47.02%
Properties: Liquid, bp760 134-137°.
Boiling point: bp760 134-137°
Derivative Type: Ethyl ester
Molecular Formula: C5H8O3
Molecular Weight: 116.12
Percent Composition: C 51.72%, H 6.94%, O 41.33%
Properties: Liquid, bp760 155°; bp750 147.5°; bp42 69-71°; bp20 66° also 56°. Prepn from ethyl lactate by oxidation with KMnO4: Cornforth, Org. Synth. coll. vol. IV, 467 (1963).
Boiling point: bp760 155°; bp750 147.5°; bp42 69-71°; bp20 66° also 56°
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