Phosphotungstic acid hydrate
CAS 12501-23-4
EC 235-087-6
Formula H2O.xH.xO40PW12
MW 348.86 g/mol
Inorganic Acids Pharmaceuticals & HealthcareBiotechnology & Life SciencesPrinting & Packaging CatalysispH Regulation & Buffering
Description
Phosphotungstic acid hydrate (CAS 12501-23-4, EC 235-087-6) is an inorganic heteropolyacid composed of tungsten, phosphorus, and oxygen, commonly abbreviated as PTA or H3PW12O40. It is also known as tungstophosphoric acid and dodecatungstophosphoric acid. No E-code designation applies to this substance.
In pharmaceutical manufacturing, PTA functions as a precipitating agent for alkaloid isolation, forming insoluble salts that enable selective separation of active compounds. In catalysis, its strong Brønsted acidity drives acid-catalysed reactions including esterification and condensation. It is also used in histological staining protocols, where it binds selectively to collagen and connective tissue structures.
Phosphotungstic acid hydrate is supplied as a crystalline solid and is subject to REACH registration requirements within the European Union. Procurement teams should confirm supplier documentation for purity grade and GHS-compliant safety data sheets. Standard packaging formats include amber glass or HDPE containers to prevent photodegradation.
In pharmaceutical manufacturing, PTA functions as a precipitating agent for alkaloid isolation, forming insoluble salts that enable selective separation of active compounds. In catalysis, its strong Brønsted acidity drives acid-catalysed reactions including esterification and condensation. It is also used in histological staining protocols, where it binds selectively to collagen and connective tissue structures.
Phosphotungstic acid hydrate is supplied as a crystalline solid and is subject to REACH registration requirements within the European Union. Procurement teams should confirm supplier documentation for purity grade and GHS-compliant safety data sheets. Standard packaging formats include amber glass or HDPE containers to prevent photodegradation.
Physical Properties
| Melting Point | ~95 °C(lit.) |
| Boiling Point | 107.9°C[at 101 325 Pa] |
| Density | 3.88[at 20℃] |
| Appearance | Crystalline |
| Color | White |
| Form | Solid |
| Water Solubility | soluble |
| Vapor Pressure | 19.2hPa at 20℃ |
| pH | 1.3 (20g/l, H2O, 20℃) |
Trade & Regulatory
| HS Code | 28111990 |
| UN Number | 3260 |
| ADR Class | 8 |
| Packing Group | III |
| Storage Class | 8B - Non-combustible corrosive hazardous materials |
| WGK (Germany) | 3 |
Other Names
12-TUNGSTOPHOSPHATEPHOSPHOTUNGSTIC ACIDTUNGSTOPHOSPHORIC ACIDTungsten Phosphide (W12P)DODECA-TUNGSTOPHOSPHORIC ACIDPHOSPHOTUNGSTIC ACID N-HYDRATEPhosphoric acid, tungsten complex12-TUNGSTOPHOSPHORIC ACID HYDRATE
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