DL-Lactic Acid

Title: DL-Lactic Acid
CAS Registry Number: 598-82-3
CAS Name: 2-Hydroxypropanoic acid
Additional Names: racemic lactic acid; ordinary lactic acid; a-hydroxypropionic acid; Milchsäure (German)
Trademarks: Lactovagan (Schwartzhaupt); Tonsillosan (Lösung) (Spitzner)
Molecular Formula: C3H6O3
Molecular Weight: 90.08
Percent Composition: C 40.00%, H 6.71%, O 53.28%
Literature References: Occurs in sour milk as a result of lactic acid bacteria; also found in molasses due to partial conversion of sugars, in apples and other fruits, tomato juice, beer, wines, opium, ergot, foxglove, and several higher plants, especially during germination. Lactic acid is prepd technically by "lactic acid fermentation" of carbohydrates such as glucose, sucrose, lactose with Bacillus acidi lacti or related organisms such as Lactobacillus delbrueckii, L. bulgaricus etc. The fermentation is carried out at relatively high temps. Produced commercially by fermentation of whey, cornstarch, potatoes, molasses. Review on the production of lactic acid by fermentation: S. C. Prescott, C. G. Dunn, Industrial Microbiology (McGraw-Hill, New York, 3rd ed., 1959) pp 304-331. Chem prepns from acetaldehyde and CO in dil H2SO4 at 130-200° and 900 atm: Loder, US 2265945 (1938 to du Pont); by hydrolysis of hexoses with NaOH: Lock, US 2382889 (1943). Prepn of crystalline lactic acid: Borsook et al., J. Biol. Chem. 102, 449 (1933). Toxicity data: Smyth et al., J. Ind. Hyg. Toxicol. 23, 259 (1941). Comprehensive description: F. J. Al-Shammary et al., Anal. Profiles Drug Subs. Excip. 22, 263-316 (1993).
Properties: Crystals, mp 16.8°. bp14-15 122°; bp0.5-1 82-85°. pKa at 25° 3.86. nD20 1.4262. Heat of combustion at constant pressure 3615 cal/kg. Volatile with superheated steam. Sol in water, alc, furfurol; less sol in ether. Practically insol in chloroform, petr ether, carbon disulfide. Caustic in concd solns. LD50 orally in rats: 3.73 g/kg (Smyth).
Melting point: mp 16.8°
Boiling point: bp14-15 122°; bp0.5-1 82-85°
pKa: pKa at 25° 3.86
Index of refraction: nD20 1.4262
Toxicity data: LD50 orally in rats: 3.73 g/kg (Smyth)
Derivative Type: Barium salt
CAS Registry Number: 54983-89-0
Additional Names: Barium lactate
Molecular Formula: C6H10BaO6
Molecular Weight: 315.47
Percent Composition: C 22.84%, H 3.20%, Ba 43.53%, O 30.43%
Properties: Powder. Poisonous! Sol in water, dil alcohol.
Derivative Type: Copper salt dihydrate
CAS Registry Number: 5893-64-1
Additional Names: Cupric lactate
Molecular Formula: C6H10CuO6.2H2O
Molecular Weight: 277.72
Percent Composition: C 25.95%, H 5.08%, Cu 22.88%, O 46.09%
Properties: Green to blue crystals. Readily sol in water. Practically insol in alcohol.
Use: In dyeing baths, as mordant in printing woolen goods, solvent for water-insoluble dyes (alcohol-soluble induline, nigrosine, spirit-blue); reducing chromates in mordanting wool; manuf cheese, confectionery; acidulant in beverages; for acidulating worts in brewing, for removing Clostridium butyricum in manuf of yeast; dehairing, plumping, and decalcifying hides; solvent for cellulose formate; flux for soft solder; manuf lactates which are used in food products, in medicine, and as solvents; plasticizer, catalyst in the casting of phenolaldehyde resins.
Therap-Cat: Acidulant.
Therap-Cat-Vet: Has been used as a caustic, and in dilute solutions to irrigate tissues; as an intestinal antiseptic and antiferment.
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