Phosphate monoesters alkali

Phosphoric acid diesters are prepared by treating a liquid slurry of phosphate monoester with epoxides in the presence of alkali compounds. Thus a mixture of monolauryl phosphate sodium salt and triethyl amine in water was treated with glycidol at 80°C for 8 h to give 98% lauryl(2,3-dihydroxypropyl)phosphate sodium salt [13]. 

The resulting cyclic phosphate diester is hydrolyzed readily in acid or alkali to the phosphate monoester. 

Gomez-Tagle P, Vargas-Zuniga I, Taran O, Yatsimirsky AK. Solvent effects and alkali metal ion catAysis in phosphodiester hydrolysis. J Org Chem. 2006 71 9713-9722. de Souza EF, lonescu LG. MiceUar-catAyzed reactions of a phosphate ester effect of the dielectric constant of the medium. Colloid Surf A. 1999 149 609-615. Stockbridge RB, Wolfenden R. Phosphate monoester hydrolysis in cyclohexane. JAm Chem Soc. 2009 131 18248-18249. 

There are some means for synthesis of defined primary or secondary esters. Monoester salts of phosphoric acid, for instance, are prepared by addition of alcohol or ethoxylated alcohol, alkali fluoride, and pyrophosphoryl chloride (C12P0)20 in a molar ratio of 0.9-1.5 0.05-1 1.0 at -50 to +10°C and hydrolysis of the Cl-containing intermediates with base. Thus, 32.3 g (C12P0)20 was treated at -50°C with 23.9 g lauryl alcohol in the presence of 0.7 g KF and the mixture was slowly warmed to room temperature and hydrolyzed with H20 and 40% NaOH to give 83% sodium monolauryl phosphate. The monoester salts showed comparable or better washing and foaming efficiency than a commercial product [12]. 

Alkyl phosphates, also coco based, are formed by the reaction of fatty alcohol with phosphorous pentoxide. The product is a mixture of monoesters and diesters. Its sodium salt (MAP) is reportedly mild and is used in facial wash, such as Kao s Biore. Other uses are as antistatics in textile auxiliaries, corrosion inhibitors, surfactant additives for extreme pressure (EP) lubricants, and surfactant components in alkali and acid cleaners. Coco-based alkyl polyglycosides (APG) have been successfully produced and marketed by Henkel in the United States. The alkyl polyglycoside fuUy satisfies the demand for a mild surfactant and is completely biodegradable. 

Amino acid analyses of phosvitin preparations also indicated inhomogeneity. It is striking, however, that an equal number of )3-hydroxyamino acids and of phosphorus atoms were found to be present. The phosphorus is alkali-labile at room temperature. Phosvitin is readily dephosphorylated with the aid of an acid phosphatase from citrus fruits (5). Bone phosphatase, on the other hand, does not liberate phosphorus. Moreover, the base binding capacity of this protein indicates that all of the phosphate groups are present in the form of monoesters with two dissociable hydroxyls. 

Commercial phosphate esters are usually mixtures of the free acids, although they may be sodium or triethanolamine salts. Monoesters nearly always contain some diester, and diesters both mono- and triester, with the nominal product predominating. They cannot be hydrolysed by either acids or alkalis at normal temperatures, but acid hydrolysis with strong acid at high temperature may be effective. 

The phosphate esters are converted to the free acid form, if they are present as salts, and determined by alkali titration. Monoesters have one weakly acidic and one strongly acidic proton. Diesters are strongly acidic. 

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