Phosphorous acid CAS#13598-36-2

Serves as a key intermediate for the preparation of various phosphorus compounds.
Used to produce phosphonates for water treatment, including scale inhibition, corrosion control, and chlorine stabilization.
Alkali metal salts (phosphites) act as effective agricultural fungicides and high-quality sources of plant phosphorus nutrition.
Functions in stabilizing plastic mixtures, protecting corrosion-prone metal surfaces at high temperatures, and producing lubricants and lubricant additives.

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Product Details

Phosphorous Acid CAS#13598-36-2

Phosphorous acid serves as an important intermediate for synthesizing various phosphorus compounds. It is a key raw material for producing phosphonates used in water treatment, including iron and manganese control, scale prevention and removal, corrosion inhibition, and chlorine stabilization. Its alkali metal salts (phosphites) are widely applied as agricultural fungicides (e.g., for Downy Mildew) and as an excellent source of plant phosphorus nutrition. Additionally, phosphorous acid is employed to stabilize plastic mixtures, protect corrosion-prone metal surfaces at high temperatures, and manufacture lubricants and lubricant additives.

Phosphorous acid CAS#13598-36-2

Phosphorous acid Chemical Properties

Melting point	73 °C
Boiling point	200 °C
density	1.651 g/mL at 25 °C(lit.)
vapor pressure	0.001Pa at 20℃
Fp	200°C
storage temp.	0-6°C
solubility	DMSO (Slightly), Methanol (Slightly), Water (Sparingly)
pka	pK1 1.29; pK2 6.74(at 25℃)
form	Crystals
color	White
Specific Gravity	1.651
PH	pKa1= 1.10, pKa2 = 6.33(25℃)
Water Solubility	SOLUBLE
Sensitive	Air Sensitive & Hygroscopic
Merck	147346
Stability:	Stable. Incompatible with strong bases. Hygroscopic.
InChI	1S/H3O3P/c1-4(2)3/h4H,(H2,1,2,3)
InChIKey	ABLZXFCXXLZCGV-UHFFFAOYSA-N
SMILES	[H]P(O)(O)=O
CAS DataBase Reference	13598-36-2(CAS DataBase Reference)
NIST Chemistry Reference	(HO)2HPO(13598-36-2)
EPA Substance Registry System	Phosphonic acid (13598-36-2)

Safety Information

Hazard Codes	C
Risk Statements	22-35
Safety Statements	26-36/37/39-45
RIDADR	UN 2834 8/PG 3
WGK Germany	1
RTECS	SZ6400000
F	3
TSCA	TSCA listed
HazardClass	8
PackingGroup	III
HS Code	28092019
Storage Class	8A - Combustible corrosive hazardous materials
Hazard Classifications	Acute Tox. 4 Oral
	Eye Dam. 1
	Met. Corr. 1
	Skin Corr. 1A

Phosphorous acid CAS#13598-36-2

Product Application of Phosphorous Acid CAS#13598-36-2

Phosphorous acid (H₃PO₃, orthophosphorous acid) can serve as a key reactant in the synthesis of:

α-aminomethylphosphonic acids through Mannich-type multicomponent reactions
1-aminoalkanephosphonic acids via amidoalkylation followed by hydrolysis
N-protected α-aminophosphonic acids (phospho-isosteres of natural amino acids) through amidoalkylation reactions

Phosphorous acid CAS#13598-36-2