Applications
Polyphosphoric acid is used as a dehydrating agent, cyclizing agent, acylating agent, analytical reagent and as a ring closing reagent. It is used in the production of phosphate esters, acid phosphates and pharmaceuticals. It is involved in metal treatment and as an asphalt and a bitumen additive. Furthermore, it is employed for the determination of tryptophan and used a reagent for the alkylation and acylation reactions of aromatic and alkenic compounds.

Solubility
Miscible with water.

Notes
Hygroscopic. Keep the container tightly closed in a dry and well-ventilated place. Incompatible with bases. It reacts with water violently to generate heat and phosphoric acid.