Phosphorous acid
Synonyms: Orthophosphorous acid, Phosphorous acid

CAS No.: 13598-36-2 EINECS: 237-066-7

Molecular Formula: H3PO3 Molecular Weight: 82.00
Testing item  Top grade  First grade
Main content
(based on H3PO3 ), %¡Ý  99.0  99.0
Iron (based on Fe), %¡Ü  0.001  0.003
Chloride (based on CL), % ¡Ü  0.01  0.02
Sulfate (based on SO4), %¡Ü  0.008  0.01
Phosphate
(based on PO4), %¡Ü  0.2  0.6
Appearance  Pure white crystal  White crystal
70% aqueous solution test  Colorless transparent  Colorless transparent, without impurities
Liquid phosphorous acid, %¡Ý  70-80  Colorless, transparent

Properities:

Phosphorous acid is a clear to yellowish crystalline solid with a garlic like odour melting at 73 C, decomposes at 200 C. It is very soluble in water and in alcohol. This compound contains one direct P-H bond (which is not very acidic) and only two hydrogens bonded to oxygen (which are acidic). The structure of this material is more correctly written (HO)2HPO. For this reason, this dibasic acid forms two series of salts, one containing the dihydrogen phosphite ion, H2PO3 -, and the other containing the hydrogen phosphite ion, HPO32-. It is prepared by hydrolysis of phosphorus trichloride (or tetraphosphorus hexaoxide) with alcohols or phenols. Phosphorous acid esters are called phosphite with the formula (RO)3P. Phosphorous acid and phosphite are used as reducing agents in chemical industry because of easy oxidation property to phosphoric acid. They are used as antioxidant, stabilizer and chelating agent in plastic system. They are used as solvent in paint and as flame retardant on fibres. They are used as a chemical intermediate in the production of pharmaceutical ingredients, pesticides, optical brighteners and in lubricant additives and adhesives.


Applications:
Raw material to prepare phosphites; Stabilizers for plastics; Water treatment; Bleaching and Cleaning industry; Chemical manufacturing. Mainly used in phosphate, synthetic fiber and organophosphorus pesticide etc., Also used in producing high performance water treating agent ATMP.

Packing & storage:
For export: Three-ply board drum lined with two-layer vinyon bag, N. W.: 50kg per drum. For domestic sale: Vinyon bag, N. W.: 30kg per bag, or metal pail lined with two-layer vinyon bag, N. W.: 25kg per bag. The sign of "corrosive article" should be on the packing.

Keywords:
Orthophosphorous acid, Phosphorous acid