Physical and chemical properties of lactic acid

Pure Lactic acid liquid, is a colorless to pale yellow liquid. Odorless, hygroscopic. The relative density of 1.2060 (25/4 ℃). Melting point 18 ℃. Boiling point 122 ℃ (2kPa). Refractive index nD (20 ℃) ​​1.4392. With water, ethanol, glycerol miscible, acidic aqueous solution, PKa = 3.85. Insoluble in chloroform, carbon disulfide and petroleum ether. Heating under normal pressure, concentrated to 50%, the part becomes the lactic anhydride, product often contains 10% to 15% of the milk anhydride. As a hydroxyl group and a carboxyl group, under certain conditions, the esterification reaction can occur, the potassium lactate has three.
Toxicity: Rat oral LD50 for 3.73g/kg weight; ADI Unlimited regulations. Lactic acid has three isomers: DL-type, D-type and L-type. The rats were divided into three groups, each dosage dose of 1.7g/kg body weight of DL-type, D-type and L-lactic acid, oral anatomy detected three hours later, DL-lactic acid can increase the liver glycogen , 40% to 95% within 3h absorption and transformation; D-and L-lactic acid in the blood lactate increased, the urine excreted.