Lactic acid

• CAS No:

50-21-5

• Formula:

C3H6O3

• Chemical Name:

Lactic acid

Description

Lactic acid consists of a mixture of 2-hydroxypropionic acid, its condensation products, such as lactoyllactic acid and other polylactic acids, and water. It is usually in the form of the racemate, (RS)-lactic acid, but in some cases the (S)-(+)-isomer is predominant.
Lactic acid is a practically odorless, colorless or slightly yellowcolored, viscous, hygroscopic, nonvolatile liquid. Lactic acid, CH3CHOHCOOH, also known as 2-hydroxypropanoic acid, is a hygroscopic liquid that exists in thr

Lactic acid Basic Attributes

Molecular Weight ：90.0779

Exact Mass ：200-018-0

EC Number ：203-872-2

Characteristics

PSA ：57.53

XLogP3 ：-0.7

Appearance ：Colorless to yellow liquid

Density ：1.249 g/cm3 @ Temp: 15 °C

Melting Point ：16.8 °C

Boiling Point ：122 °C @ Press: 14-15 Torr

Flash Point ：109.9ºC

Refractive Index ：1.4252-1.4272

Water Solubility ：Solubility in water: miscible

Storage Conditions ：2-8ºC

Vapor Pressure ：19 mm of Hg (@ 20°C)

Odor ：Odorless

Taste ：Mild acid taste and does not overpower weaker aromatic flavors

PH ：The pH of a 10 wt% aqueous solution of lactic acid is 1.75

PKA ：3.86(at 20 °C)

Lactic acid Use

Lactic acid is an organic compound with the formula CH3CH(OH)CO2H. In its solid state, it is white and water-soluble. In its liquid state, it is clear. It is produced both naturally and synthetically. With a hydroxyl group adjacent to the carboxyl group, lactic acid is classified as an alpha-hydroxy acid (AHA). In the form of its conjugate base called lactate, it plays a role in several biochemical processes.In solution, it can ionize a proton from the carboxyl group, producing the lactate ion CH 3CH(OH)CO− 2. Compared to acetic acid, its pKa is 1 unit less, meaning lactic acid deprotonates ten times more easily than acetic acid does. This higher acidity is the consequence of the intramolecular hydrogen bonding between the α-hydroxyl and the carboxylate group.Lactic acid is chiral, consisting of two optical isomers. One is known as L-(+)-lactic acid or (S)-lactic acid and the other, its mirror image, is D-(−)-lactic acid or (R)-lactic acid. A mixture of the two in equal amounts is called DL-lactic acid, or racemic lactic acid.Lactic acid is hygroscopic. DL-lactic acid is miscible with water and with ethanol above its melting point which is around 17 or 18°C. D-lactic acid and L-lactic acid have a higher melting point.In animals, L-lactate is constantly produced from pyruvate via the enzyme lactate dehydrogenase (LDH) in a process of fermentation during normal metabolism and exercise. It does not increase in concentration until the rate of lactate production exceeds the rate of lactate removal, which is governed by a number of factors, including monocarboxylate transporters, concentration and isoform of LDH, and oxidative capacity of tissues. The concentration of blood lactate is usually 1–2 mmol/L at rest, but can rise to over 20mmol/L during intense exertion and as high as 25mmol/L afterward.In industry, lactic acid fermentation is performed by lactic acid bacteria, which convert simple carbohydrates such as glucose, sucrose, or galactose to lactic acid. These bacteria can also grow in the mouth; the acid they produce is responsible for the tooth decay known as caries. In medicine, lactate is one of the main components of lactated Ringer's solution and Hartmann's solution. These intravenous fluids consist of sodium and potassium cations along with lactate and chloride anions in solution with distilled water, generally in concentrations isotonic with human blood. It is most commonly used for fluid resuscitation after blood loss due to trauma, surgery, or burns.