Lactic acid

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

1. Starch raw materials, molasses, starch sugar as raw materials, after saccharification with the appropriate acid lactic acid bacteria or Bacillus in the appropriate conditions of fermentation, the calcium carbonate and precipitation, and then dilute sulfuric acid to lactic acid , And then refined after lactic acid products can be obtained. Starch saccharification ↓ saccharification enzyme ↓ lactic acid bacteria and pressure filtration concentrated cooling acidification bleaching ↓ activated carbon ↓ sulfuric acid pumping vacuum concentration cation exchange anion exchange vacuum concentration decolorization filter finished product purification method: lactic acid has a strong hygroscopicity, concentrated partial lactic acid Acid anhydride, heating itself prone to esterification reaction. Therefore, even if distilled under reduced pressure, it is difficult to obtain pure product. The fraction was fractionated at 13.3 Pa, and the distillate was dissolved with a mixture of equal amounts of ether and isopropyl ether to cool the crystals at an ice salt temperature. Filtered and then repeated twice. It can also be crystallized at the dry ice temperature. The solvent may also be used in a mixed solvent of equal amounts of benzene and diethyl ether containing 5% petroleum ether (b.p. 60 to 80C).
2. There are three methods of producing lactic acid in industry, fermentation, acetaldehyde and acrylonitrile. The most widely used is the fermentation method, is the raw material containing starch sucrose, beet sugar, molasses or grain starch as raw material, saccharification access lactic acid bacteria, ph = 5, 49 ℃ fermentation 3 to 4 days, with calcium carbonate And, while hot filter, refined with calcium lactate. And then acidified with sulfuric acid, filtered, the filtrate concentrated, decolorization, impurity that product. 3 synthesis of chemical synthesis of acetaldehyde and acrylonitrile method, the resulting lactic acid DL. Lactic acid.
(1) acetaldehyde method to acetaldehyde and hydrocyanic acid as raw materials to produce milk, the hydrolysis of crude lactic acid, crude lactic acid by ethanol esterification and then hydrolysis of lactic acid: acetaldehyde and cold hydrocyanic acid into the reaction And then add the water and sulfuric acid catalyzed hydrolysis of lactic acid; ethanol after esterification distillation of ethyl lactate; finally sent to the concentration of concentrated decomposition of refined milk lactic acid.
(2) Acrylonitrile acrylonitrile hydrolysis of crude lactic acid, and then esterified by methanol after hydrolysis of lactic acid: acrylonitrile sent to the reactor, in the catalytic hydrolysis of sulfuric acid to produce a mixture of lactic acid and ammonium sulfate. The mixture into the esterification reactor and methanol esterification, separation of ammonium sulfate, the crude ester to send distillation tower, the bottom of the fine ester. Refined ester distillation tower, heating decomposition, was dilute lactic acid. Finally, the product is concentrated by vacuum.
4. Tobacco: BU, 26. In the food industry by the glucose, starch, milk fermentation preparation; acetaldehyde and hydrocyanic acid reaction to produce cyanoethanol, and then hydrolyzed to produce crude lactic acid, vinegar lactic acid into ethyl lactate, and then hydrolyzed to pure lactic acid.

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.

Molecular Weight:90.08
XLogP3:-0.7
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:90.031694049
Monoisotopic Mass:90.031694049
Topological Polar Surface Area:57.5
Heavy Atom Count:6
Complexity:59.1
Undefined Atom Stereocenter Count:1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes