Polyphosphoric acid (PPA) is a mixture of linear polymers formed through the dehydration and condensation of phosphoric acid molecules. At room temperature, it is a colorless, viscous liquid characterized by strong dehydrating properties, Brønsted acidity, and corrosiveness; it is widely used as a catalyst for cyclization and acylation reactions in organic synthesis.

CHEMICAL PROPERTIES

PRODUCT USAGE

Organic Synthesis: Serves as a key cyclizing agent, acylating agent, and dehydrating agent in processes such as Fischer-Indole synthesis, the Beckmann rearrangement, and condensation reactions; functions as both a solvent and a catalyst.

Industrial Auxiliaries: Used as a catalyst for petroleum alkylation, in metal surface treatment (phosphating), as a raw material for flame retardants, as an analytical reagent, and as a substitute for orthophosphoric acid.

Derivative Applications: Its salts (e.g., sodium polyphosphate) are used as food water-retention agents and chelating agents for water treatment; however, polyphosphoric acid itself is not used directly in food.