Application of Polyphosphoric acid

General description

Phosphoric acid appears as a clear colorless liquid or transparent crystalline solid. The pure solid melts at 42.35°C and has a density of 1.834 g / cm3. Liquid is usually an 85% aqueous solution. Shipped as both a solid and liquid. Corrosive to metals and tissue. Used in making fertilizers and detergents and in food processing. Phosphoric acid is a phosphorus oxoacid that consists of one oxo and three hydroxy groups joined covalently to a central phosphorus atom. It has a role as a solvent, a human metabolite, an algal metabolite and a fertilizer. It is a conjugate acid of a dihydrogenphosphate and a phosphate ion.

Polyphosphate is an inorganic substance with the chemical formula of Hn+2PnO3n+1. It is a colorless, transparent and viscous liquid with corrosivity. It is a secondary inorganic acid corrosive substance. Polyphosphate is a proton acid, which can dissolve a variety of low molecular and high molecular organic compounds. It is used as water loss agent, cyclizing agent and acylating agent in organic synthesis. It is a catalyst or solvent for condensation, cyclization, rearrangement, substitution and other reactions. Polyphosphate (PPE) is sometimes used to increase the solubility of polyphosphate in organic solvents. In addition, polyphosphate is also used as a substitute for orthophosphoric acid and analytical reagent

Application and pharmacology

1.Phosphoric Acid is a colorless, odorless phosphorus-containing inorganic acid. Phosphoric acid is a sequestering agent which binds many divalent cations, including Fe+, Cu+, Ca+, and Mg+. Phosphoric acid is used in dentistry and orthodontics as an etching solution, to clean and roughen the surfaces of teeth where dental appliances or fillings will be placed. In addition, phosphoric acid is a constituent in bone and teeth, and plays a role in many metabolic processes.

Polyphosphate (PPA) is a chemical modifier. When it is added into asphalt for modification, it can react with asphalt to form new chemical bonds and chemical groups, so as to improve the performance of asphalt. Compared with polymer modified asphalt, it has the advantages of low price, simple modification process and good high-temperature storage stability. In recent years, the application of PA modified asphalt has gradually increased, and the research on its performance has attracted more and more attention of road researchers：

2. In order to master the performance of polyphosphate (PPA) modified asphalt mortar and prepare asphalt mortar with different PPA content and powder binder ratio, the shear strength, high temperature performance and low temperature performance were studied by cone, dynamic shear rheological (DSR) and bending beam rheological (BBR) tests. The results show that the shear strength of Papa modified asphalt mortar increases with the increase of Papa content and powder binder ratio, in which the content of Papa exceeds 1 The increase rate decreased after 5% The powder binder ratio exceeds 1 The increase rate increased after； With the increase of PA content, the high-temperature deformation resistance of asphalt mortar increases, the proportion of elastic components increases, and the temperature sensitivity of high-temperature performance decreases. When the powder binder ratio increases, the high-temperature deformation resistance increases, and the proportion of elastic components and the temperature sensitivity of high-temperature performance remain basically unchanged; The low temperature performance of PA modified asphalt mortar increases with the increase of PA content It decreases with the increase of powder binder ratio, but the test temperature decreases to At 12℃ and below, both effects are weakened, especially for the content of PA.[1,2]

Synthesis

Polyphosphate is composed of phosphoric acid (H3PO4) is prepared by heating, dehydration and condensation. It can also be obtained by adding phosphorus pentoxide to pure water and then heating and condensation. It is a colorless and transparent syrupy substance at room temperature. It is solid glass at low temperature and has fluidity when heated to 50 ~ 60 ℃. It is easy to deliquesce, miscible with water and hydrolyzed to phosphoric acid. The concentration of polyphosphate can be expressed in two ways, one is P2O5%, the other is H3PO4 is 100% , expressed by the content of H3PO4 in polyphosphoric acid. The acidity of polyphosphate is weaker than that of nitric acid and sulfuric acid, and it has no oxidation ability. Hygroscopic and deliquescent. In case of H foaming agent, it will cause combustion. Phosphoric acid and phosphorus pentoxide are heated for polymerization reaction, hydrogen peroxide is added to remove iron ions in the solution, purified, cooled and filtered to prepare finished polyphosphate.

packaging and storage

Packed in polyethylene plastic drums with a net weight of 40/kg. The packaging barrel shall be clearly marked with "corrosive articles". It belongs to two pole inorganic acid corrosive goods. It shall be stored in a cool and ventilated warehouse, and the container must be sealed. It shall not be stored and transported together with alkaline goods, inflammables, oxidants, etc. It shall be protected from rain and sun during transportation. Handle with care during loading and unloading to prevent container rupture and leakage. For convenience, please soak it in a warm car or 50 ° C water bath the day before use. In case of fire, sand and dry powder fire extinguishers can be used.[3,4]

Reference

1.Chang Xiaorong: Study on properties of polyphosphate / liquid rubber composite modified asphalt and mixture: Chang'an University, 2021.

2.Song Congcong, Zhang Qing, Wei Yannan, etc.: performance of polyphosphate modified asphalt mortar, highway, 2021, issue 04, pages 268-273.

3.Wang P., Chen D. & Gong L., "Recent Progress in Asymmetric Relay Catalysis of Metal Complex with Chiral Phosphoric Acid," Topics in Current Chemistry, Vol.378, No.1(2020).

4.Abdel Moty S. G., Hussein M. A. & Abdel Aziz S. A. et al., "Design and synthesis of some substituted thiazolo[3,2-a]pyrimidine derivatives of potential biological activities," Saudi Pharmaceutical Journal, Vol.24, No.2(2016), pp.119-132.

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