PREPARATION AND CHARACTERIZATION OF POLYSACCHARIDE PHOSPHATES

Polysaccharide phosphate monoesters with degrees of substitution up to 1.75 can be made by reaction of polysaccharides with a tetrapolyphosphoric acid-trialkylamine mixture of about 3:1 molar ratio at temperatures of 120 °. Phosphate monoesters of amylose, amylopectin, waxy corn starch, dextran, and cellulose are prepared. The esters are very resistant to saponification but are less stable to acid hydrolysis. Viscosities of polysaccharide phosphates increase with ester content and increase very rapidly with solution concentration although the solutions are thixotropic. The solution viscosities show some temperature dependence and are lowered by addition of salts. Polysaccharide phosphate monoesters do not precipitate soluble proteins from neutral solutions but may cause precipitation at low pH values. © 1969.