The manufacturer tells you about the properties and uses of polyphosphoric acid
Polyphosphoric acid , English name Polyphosphoric acid, molecular formula H6P4O13 (approximate), molecular weight: 337.93, is a colorless viscous liquid, easy to deliquescence. Polyphosphoric acid (PPA) has strong dehydration, low nucleophilicity and moderate acidity. Unlike sulfonic acid, polyphosphoric acid generally does not oxidize the reactants and can dissolve in organic solvents. Although its acidity is weaker than sulfonic acid, its dehydration property is comparable to that of 100% sulfonic acid, so it is widely used in laboratory. Intramolecular cyclization of carboxylic acids, esters, ketones, aldehydes, alcohols, alkenes and hydrazones can be catalyzed by polyphosphoric acid, such as the synthesis of quinone (Formula 1) catalyzed by PPA. Many quinolines and quinoline derivatives are synthesized under the catalysis of PPA. For example, the cyclization of N-ethoxyformyl spiro-tetrahydroquinoline catalyzed by excessive PPA yields about 60% (Form 2). It is used as cyclizing a...