Lactic acid - Preparation of synthesis

Lactonitrile law: Lactonitrile method is to acetaldehyde and hydrogen cyanide cold milk continuously fed to the reactor to generate a nitrile (or Nitrile directly with the milk as raw material), with a pump into the milk nitrile hydrolysis reactor, into sulfuric acid and water, the milk Sodium lactate crude lactic acid. And then give it away crude lactic acid esterification reactor, adding ethanol esterification by Distillation, concentration, lactic acid decomposition was fine. American Sterling Chemical Company and Japan Musashino of Learn companies are adopting this synthesis of lactic acid.
Acrylonitrile law: acrylonitrile and potassium lactate method is hydrolyzed in sulfuric acid fed to the reactor, then the water Hydrolysates anyone to esterification reaction with methanol reactor; then after separation of the ammonium bisulfate, sending crude ester Into the distillation column bottom is fine ester; then refined into a second distillation column ester, thermal decomposition, bottom In dilute acid, concentrated by vacuum to obtain the product.
Propionic acid method: method propionic acid as raw materials, through chlorination, hydrolysis of the crude lactic acid; re-esterification, Distillation, hydrolysis products. This method is more expensive raw materials, only a few companies such as Japan's road contest Manufacturers to adopt. Reaction is as follows: CH3CH2COOH Cl2 one → CH3CHClCOOH NaOH- → CH3CH (OH) COOH NaCl