Propanoic acid, 2-hydroxy-. Lactic acid [50-21-5].
Lactic Acid is a mixture of lactic acid (C3H6O3) and lactic acid lactate (C6H10O5) equivalent to a total of not less than 88.0 percent and not more than 92.0 percent, by weight, of C3H6O3. It is obtained by the lactic fermentation of sugars or is prepared synthetically. Lactic Acid obtained by fermentation of sugars is levorotatory, while that prepared synthetically is racemic. [NOTE—Lactic Acid prepared by fermentation becomes dextrorotatory on dilution, which hydrolyzes L-( )-lactic acid lactate to L-(+)-lactic acid.]
Identification: It meets the requirements of the test for Lactate.
Specific rotation: between 0.05 and +0.05 , for racemic Lactic Acid.
Readily carbonizable substances: Rinse a test tube with sulfuric acid, and allow to drain for 10 minutes. Add 5 mL of sulfuric acid to the test tube, carefully overlay it with 5 mL of Lactic Acid, and maintain the tube at a temperature of 15 : no dark color develops at the interface of the two acids within 15 minutes.
Residue on ignition: not more than 3 mg, from a 5-mL portion (0.05%).
Sugars: To 10 mL of hot alkaline cupric tartrate add 5 drops of Lactic Acid: no red precipitate is formed.
Chloride: To 10 mL of a solution (1 in 100) acidified with nitric acid add a few drops of silver nitrate: no opalescence is produced immediately.
Sulfate: To 10 mL of a solution (1 in 100) add 2 drops of hydrochloric acid and 1 mL of barium chloride: no turbidity is produced.
Heavy metals: 0.001%.
Limit of citric, oxalic, phosphoric, or tartaric acid: To 10 mL of a solution (1 in 10) add 40 mL of calcium hydroxide, and boil for 2 minutes: no turbidity is produced.
Assay: To about 2.5 mL of Lactic Acid, accurately weighed in a tared 250-mL flask, add 50.0 mL of 1 N sodium hydroxide, and boil the mixture for 20 minutes. Add phph, and titrate the excess alkali in the hot solution with 1 N sulfuric acid. Perform a blank determination.
Each mL of 1 N sodium hydroxide is equivalent to 90.08 mg of C3H6O3.
Ph Eur
C3H6O3 -- 90.1 -- 50-21-5
DEFINITION
Mixture of 2-hydroxypropanoic acid, its condensation products, such as lactoyl-lactic acid and polylactic acids, and water. The equilibrium between lactic acid and polylactic acids depends on the concentration and temperature. It is usually the racemate ((RS)-lactic acid).
Content: 88.0 per cent m/m to 92.0 per cent m/m of C3H6O3.
CHARACTERS
Appearance: Colourless or slightly yellow, syrupy liquid.
Solubility: Miscible with water and with ethanol (96 per cent).
IDENTIFICATION
A. Dissolve 1 g in 10 ml of water. The solution is strongly acidic.
B. Relative density: 1.20 to 1.21.
C. It gives the reaction of lactates.
α-Hydroxypropionic Acid; 2-Hydroxypropionic Acid
C3H6O3 -- Â Formula wt 90.08
INS: 270 CAS: L(+)-Lactic Acid [79-33-4]
CAS: DL-Lactic Acid [598-82-3]
DESCRIPTION
Lactic Acid occurs as a colorless or yellow, syrupy liquid consisting of a mixture of lactic acid (C3H6O3) and lactic acid lactate (C6H10O5). It is obtained by the lactic fermentation of
sugars or is prepared synthetically. It is usually available in solutions containing the equivalent of from 50% to 90% lactic acid. It is hygroscopic, and when concentrated by boiling, the acid condenses to form lactic acid lactate, 2-(lactoyloxy)propanoic acid, that on dilution and heating, hydrolyzes to Lactic Acid. It is miscible with water and with alcohol.
Function: Acidifier.