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Material Safety Data Sheet(MSDS)

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• description

  phosphorus pentoxide, also known as phosphoric anhydride, is phosphorus oxides generated by combustion of white phosphorus, yellow or red phosphorus in dry air, soft white powder or colorless monoclinic crystal at room temperature, easily deliquescence, melting point is 580~585 ℃, relative density is 2.39, sublimation is 347 ℃. When heated under pressure to 563 ℃, crystalline substance translates to amorphous glass (melt). It is insoluble in acetone, ammonia, soluble in sulfuric acid.
  
  phosphorus pentoxide is easy to absorb moisture from the air, and have a strong dehydration, can even dehydrate concentrated sulfuric acid to produce sulfur trioxide, is a potent desiccant, reacts violently with water and emits heat and white smoke. Per mole of phosphorus pentoxide releases 68 kilocalories, usually generate metaphosphate with cold water, and generate mainly phosphoric acid with hot water. According to the amount of water added, it can generate different pentavalent phosphorus oxyacid, such as metaphosphoric acid, pyrophosphoric acid, orthophosphoric acid, etc.
  phosphorus pentoxide is used to make high purity phosphoric acid, as well as gas and liquid desiccant, organic synthetic dehydrating agent. ;

• Chemical Properties

  Phosphorus pentoxide (P₂O₅) or phosphoric anhydride is a white, highly deliquescent solid which sublimes at 300°C and reacts violently with water to give orthophosphoric acid. It is prepared by burning elemental phosphorus in excess oxygen, and then purified by sublimation. The compound is used as a drying and dehydrating agent; for example, the amides are converted into nitriles, and sulphuric acid is converted to sulphur trioxide (SO₃). The fertilizer phosphorus is specified as the weight percentage of phosphorus pentoxide.;

• Hazardous characteristics

  Non-combustible. But encountering water and organic materials such as wood, cotton or straw, it reacts violently to release heat, may cause a fire. Contacting Water, it can emit a lot of smoke and heat. The case of the moisture, it corrodes most metals slightly. A strong local irritation, vapor with dust can severely irritate the eyes, mucous membranes, skin and respiratory system, and corrode the skin, mucous membranes. Even the dust concentration of 1mg/m3, it is unbearable.
  The above information is edited by the chemicalbook of Yan Yanyong. ;

• Reference quality standards

  Item Index
  Chemically pure analytically pure specific level
  Content (phosphorus pentoxide) ≥99% ≥99.5% ≥99.5%
  Active R value 1.2 1.7 2.0
  Reducing substances (in terms P2O3) ≤0.02% ≤0.01% ≤0.005%
  Clarity test Pass Pass Pass
  Water insoluble matter ≤0.02% ≤0.01% ≤0.01%
  Total nitrogen (N) ≤0.002% ≤0.001% ≤0.001%
  Heavy Metals (in Pb) ≤0.002% ≤0.001% ≤0.001%
  Iron content (Fe) ≤0.002% ≤0.001% ≤0.001%
  Arsenic content (As) ≤0.01% ≤0.005% ≤0.0025% ;

• Reaction with water

  It reacts with cold water to produce extremely toxic metaphosphate: P2O5 + H2O = 2HPO3
  and reacts with hot water to produce ontoxic orthophosphate: P2O5 + 3H2O = (heating) 2H3PO4, an exothermic reaction, the phenomenon is not very intense. ;

• Toxicity

  Phosphorus pentoxide smoke irritates mucous membranes, has irritation and burning effects for skin (tissue dehydration).
  Maximum allowable concentration is 1mg/rn3.
  Production equipment and pipelines should be closed, and maintain good ventilation. Production workers should wear labor protective equipments and wear protective respirator, when there are phosphorus pentoxide vapor and smoke , should wear protective masks. Pay attention to protect the skin, do not import, or meet the eye. If accidentally touches the skin, immediately wash with clean water. ;

• Water absorption

  There is a strong water imbibition, and easily deliquescent in the air, corrosive to the skin. The maximum allowable concentration in the workplace is 1mg/m3. The drying efficiency of Phosphorus pentoxide is 1 cubic meter 0.00001 grams of water vapor content at 298K, namely dried by phosphorus pentoxide, water left per cubic meter of air is up to 0.00001 gram, phosphorus pentoxide can make sulfuric acid, nitric acid dehydration. When the amount of phosphorus pentoxide and water substance is 1: 6, phosphorus pentoxide can convert to orthophosphoric acid. ;

• Uses

  Used as a drying agent, dehydrating agent, sugar refining agent, and used for the preparation of phosphoric acid, phosphorous compounds and aerosol, etc. Used as a semiconductor silicon doped source, dehydration drying agent, organic synthetic condensing agent and surfactant, it is also used for preparation of high purity phosphoric acid.
  It is used as raw material for the production of high purity phosphoric acid, phosphates and phosphate, also used for the preparation of phosphorus pentoxide sol and H-based aerosol. It can be used as a desiccant of gases and liquids, dehydrating agent for organic synthesis, antistatic agents of synthetic fiber and sugar refining agent. It is also used in the manufacture of optical glass, UV transparent glass, insulating glass, microcrystalline glass and opaque glass, etc, so as to improve the dispersion coefficient and UV light through ability of the glass. Also used in the production of pharmaceuticals, pesticides, surfactants.
  It is used as the semiconductor dopant, and raw material for the preparation of high purity phosphoric acid.
  It is used as desiccant and dehydrating agent, condensing agent in organic synthesis. High purity grade phosphorus pentoxide can be used as dopant for drawing optical fiber preform, N type dopant for the manufacture of integrated circuits, used for the synthesis of optical crystal. ;

• Production method

  Reagent grade phosphorus pentoxide is as raw material, purified by burning sublimation in sufficiently dry oxygen gas stream, trapping sublimate by the condenser, to obtain high-purity phosphorus pentoxide products.
  Yellow phosphorus is heated and melted by oxidation method, transfered to the oxidation furnace for oxidation combustion reaction with dry air (via dehydration of concentrated sulfuric acid), phosphorus pentoxide produced is sublimated by heat, cold in the top of burners and falls into interior settling chamber at the bottom, to prepare pentoxide products.
  Exhaust escapes from the oxidation furnace to a cyclone to recover phosphorus pentoxide dust. Recycling and the settling chamber finished product are together packaged as a finished product. P4 + 5O2 → 2P2O5 ;

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