Polyphosphoric acid (PPA) has strong dehydration, low nucleophilic and moderate acidity. Unlike sulfonic acid, polyphosphate does not oxidize the reactants, and it is soluble in organic solvents. Although its acidity is weaker than sulfonic acid, its dehydration is equivalent to 100% sulfonic acid, so it is widely used in the laboratory.
PPA can catalyze the intramolecular cyclization of carboxylic acids, esters, ketones, aldehydes, alcohols, alkenes and hydrazone , such as the synthesis of quinone under the catalysis of PPA. Many quinolines and quinoline derivatives are synthesized under the catalysis of PPA, such as n-ethoxyformylethylspiro-tetrahydroquinoline cyclization under the catalysis of excessive PPA, the yield is about 60%.
It is used as a cyclizer and acylating agent in organic synthesis. It is also used as a substitute and analytical reagent for orthophosphate.
Post time: Jan-22-2020