Name | Pyrophosphoric acid |
Synonyms | eizh DIPHOSPHORIC ACID diphosphoric acid PYROPHOSPHORIC ACID Pyrophosphoric acid Diphosphoric(V) acid PYROPHOSPHORIC ACID, TECH. Pyrophosphoric acid syrupy Pyrophosphoric acidDiphosphoric acid |
CAS | 2466-09-3 |
EINECS | 219-574-0 |
InChI | InChI=1/H4O7P2/c1-8(2,3)7-9(4,5)6/h(H2,1,2,3)(H2,4,5,6) |
InChIKey | XPPKVPWEQAFLFU-UHFFFAOYSA-N |
Molecular Formula | H4O7P2 |
Molar Mass | 177.98 |
Density | approximate 1.9g/ml (25℃) |
Melting Point | 61 °C |
Water Solubility | 709g/100mL H2O (23°C); soluble alcohol, ether [MER06] |
Solubility | DMSO (Soluble) |
Appearance | Transparent liquid |
Merck | 13,8098 |
pKa | 0.99±0.10(Predicted) |
Storage Condition | -20°C, Hygroscopic |
Stability | Hygroscopic, Moisture Sensitive |
Sensitive | Easily absorbing moisture |
MDL | MFCD00011343 |
Physical and Chemical Properties | The nature of sugar syrup solution, solid transparent crystalline. Pyrophosphoric acid has strong hygroscopicity. Solid pyrophosphoric acid is formed by natural crystallization of a mixture of polyphosphoric acids having a P2O5 content of 79.8%± 0.2%. Soluble in ethanol, ether. When heated to a melting point or higher, it is decomposed into a liquid acid containing orthophosphoric acid, pyrophosphoric acid, trimetaphosphoric acid, polymetaphosphoric acid, and the like. Crystalline pyrophosphoric acid does not decompose much in ice water, but decomposes at high temperatures, and the amount of orthophosphoric acid increases. A typical solid crystal is pyrophosphoric acid type I (melting point 54.3 °c). The form I crystals were heated at about 50 °c for several hours in a closed tube and changed to form II (melting point 71.5 °c), which was stable at room temperature. |
Use | Used as catalyst and concealment agent |
Hazard Symbols | C - Corrosive |
Risk Codes | R22 - Harmful if swallowed R34 - Causes burns |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) |
UN IDs | UN 3260 8/PG 2 |
WGK Germany | 3 |
RTECS | JL6672500 |
FLUKA BRAND F CODES | 3-9-21 |
HS Code | 28092000 |
Hazard Class | 8 |
Packing Group | III |
there are sugar syrup solution, solid transparent crystal. Pyrophosphoric acid has strong hygroscopicity. Solid pyrophosphoric acid is formed by natural crystallization of a mixture of polyphosphoric acids having a content of P2 05 of 79.8%± 0.2%. Soluble in ethanol, ether. When heated to a melting point or higher, it is decomposed into a liquid acid containing orthophosphoric acid, pyrophosphoric acid, trimetaphosphoric acid, polymetaphosphoric acid, and the like. Crystalline pyrophosphoric acid does not decompose much in ice water, but decomposes at high temperatures, and the amount of orthophosphoric acid increases. A typical solid crystal is a type I pyrophosphoric acid (melting point 54.3 °c). The form I crystals were heated at about 50 °c for several hours in a closed tube and changed to form II (melting point 71.5 °c), which was stable at room temperature.
pyrophosphoric acid was produced by a method of dehydrating and concentrating commercially available 85% Phosphoric acid, dissolving phosphorus pentoxide in 85% Phosphoric acid, and reacting phosphorus oxychloride with 85% Phosphoric acid.
85% Phosphoric acid concentration method: the commercially available 85% Phosphoric acid is heated to about 180 ° C. Under reduced pressure to avoid local overheating and dehydrated (the weight loss of 1009 85% Phosphoric acid is about 25-30g) to prepare pyrophosphoric acid.
The method of dissolving P2 0s in 85% Phosphoric Acid: under intense stirring, P2 0s is added to phosphoric acid point by point according to the calculated amount (log 85% Phosphoric acid is added to 95 ~ log P2 0B), dissolve while heating until transparent. Water was added to the produced pyrophosphoric acid to adjust the content of P2 05 to 76% to 79%. The pyrophosphoric acid is placed naturally (to continue to be moisture-proof) and forms crystals, which take two to three days to form crystals under ice-cold to prepare pyrophosphoric acid.
The method of adding seeds in liquid pyrophosphoric acid: this is the method of mass production of high purity crystalline pyrophosphoric acid (type I or Type II), and the commercial polyphosphoric acid containing 84% P2 05 (also known as 116% phosphoric acid) dilute with water to make liquid pyrophosphoric acid (P2 05,79. 76%), add an appropriate amount (10% ~ so% by weight) of type I or Type II pyrophosphate seeds, in a dry nitrogen stream to prevent humidity, under stirring at 30~50 C, after 60~180min induction period, can be prepared crystalline pyrophosphoric acid, the purity of> 95%.
for copper plating process, adjust the pH value of the plating solution, can also be used for other plating. It can also be used as a catalyst, metal refining, organic peroxide stabilizer.
risk code: acid corrosion articles. GB 8.1. Packed in a plastic bucket with a net weight of 5kg per bucket. The inner cover of the packaging barrel shall be strictly covered, and the outer cover shall be tightened. The package shall be marked with "corrosive items. Store in a cool, dry, ventilated warehouse. In the winter cold area should pay attention to heat preservation, prevent icing, prevent container rupture leakage. It shall not be stored and mixed with alkalis, toxic substances and other corrosive substances. During transport, it is necessary to prevent rain and exposure to the hot sun. During handling, it is necessary to carry light and remove light. No violent impact is allowed to prevent the rupture of the packaging container. When there is a fire, it can be suppressed by dry sand and dry powder fire. Toxicity and protection: see industrial phosphoric acid.
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
The acidity of pyrophosphoric acid | The chain and cyclic structures of pyrophosphoric acid, tetraphosphoric acid or other polyphosphoric acid are formed by dehydration and condensation of orthophosphoric acid, All are condensation acids. Generally, the acidity of condensation acid is greater than that of monoacid. This is because the condensation acid has a large plasma volume and the negative charge density on its surface is reduced a lot, so the condensation acid is easy to dissociate protons. The greater the degree of condensation of similar oxyacids, the stronger the acidity. |
uses | moisture retention agent, quality improver, pH regulator, metal chelating agent. Used as catalyst, metal refining, stabilizer of organic peroxide. It is used to adjust the Ph value of the electroplating solution in the electroplating copper process, and it is also used for other electroplating. Used as catalyst and concealer, etc. |
toxicity | see industrial phosphoric acid. |
production method | the manufacture of pyrophosphorus includes the method of dehydrating and concentrating commercially available 85% phosphoric acid, dissolving phosphorus pentoxide in 85% phosphoric acid, and the reaction method of phosphoryl chloride and 85% phosphoric acid. 85% phosphoric acid concentration method avoids local overheating of commercially available 85% phosphoric acid, and is heated to about 180 ℃ under reduced pressure for dehydration (the weight loss of 100g 85% phosphoric acid is about 25~30g) to prepare pyrophosphoric acid. The method of dissolving P2O5 in 85% phosphoric acid under intense stirring, according to the calculation amount (100g 85% phosphoric acid plus 95~100g P2O5), P2O5 is added to phosphoric acid at 1.1 point, and dissolved while heating until transparent. Add water to the generated pyrophosphoric acid to adjust the P2O5 content to about 76% ~ 79%. Place pyrophosphoric acid naturally (to continue to prevent moisture) to form crystals, and it takes two to three days to form crystals under cold to produce pyrophosphoric acid. The method of adding seed crystals to liquid pyrophosphoric acid This is a method for mass production of high-purity crystalline pyrophosphoric acid (type I or type II). The commercially available polyphosphoric acid containing 84% P2O5 (also called 116% phosphoric acid) is diluted with water into liquid pyrophosphoric acid (P2O 579.76%), and an appropriate amount (10% ~ 50% by weight) of type I or type II pyrophosphoric acid seeds are added to prevent moisture in a dry nitrogen stream, crystalline pyrophosphoric acid with purity> 95% can be prepared after 60~180 min induction period under stirring at 30~50 ℃. |