Chromium acid monoester

Carboxylic acids and PO give a mixture that contains the monoesters of the primary and the secondary alcohol groups of PG. The monoesters may then react with additional acid to form the glycol diester. With a sufficient concentration of epoxide, the monoester may add PO to yield the ester of dipropylene glycol, higher poly(propylene glycols) and their esters, and the glycol diester. The esterification is catalyzed with sodium or potassium hydroxide, and anhydrous chromium... 

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