Polyphosphoric acid is an inorganic substance. It is a colorless, transparent, viscous liquid with corrosiveness, and is classified as a Class II inorganic acidic corrosive product.As a protic acid, polyphosphoric acid can dissolve various low-molecular-weight and high-molecular-weight organic compounds.It is used as a dehydrating agent, cyclizing agent and acylating agent in organic synthesis, acting as a catalyst or solvent for condensation, cyclization, rearrangement, substitution and other reactions.Polyphosphoric acid esters (PPE) are sometimes used to improve the solubility of polyphosphoric acid in organic solvents.In addition, polyphosphoric acid is also used as a substitute for orthophosphoric acid and as an analytical reagent.

It is used as a dehydrating agent, cyclizing agent and acylating agent in organic synthesis, and serves as a catalyst or solvent for condensation, cyclization, rearrangement, substitution and other reactions.Polyphosphoric acid esters (PPE) are sometimes used to increase the solubility of polyphosphoric acid in organic solvents.In addition, polyphosphoric acid is also used as a substitute for orthophosphoric acid and as an analytical reagent.