Description

CAS NO. *********2 FORMULA (HO)2HPO MOL WT. *2.*0 GENERAL DESCRIPTION Phosphorous acid is a clear to yellowish crystalline solid with a garlic like odour melting at *3 C, decomposes at **0 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, HPO**-. 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. PHYSICAL AND CHEMICAL PROPERTIES PHYSICAL STATE Clear to yellowish Crystal MELTING POINT *3 C BOILING POINT **0 C (Decomposes) SPECIFIC GRAVITY 1.**1 SOLUBILITY easily soluble STABILITY Has not been fully evaluated. Hygroscopic, air sensitive. APPLICATIONS Raw material to prepare phosphites; Stabilizers for plastics; Water treatment; Bleaching and Cleaning industry; Chemical manufacturing APPEARANCE Clear to yellowish Crystal PHOSPHOROUS ACID *8.5% min PHOSPHATE 0.2% max CHLORIDE 0.**5% max SULFATE 0.**8% max HEAVY METALS *5ppm max IRON *5ppm max