Phosphorous acid|CAS13598-36-2

Phosphorous acid is a dibasic acid, its acidity is slightly stronger than phosphoric acid, it has strong reducibility, easy to reduce Ag ions to silver metal, can reduce sulfuric acid to sulfur dioxide. Phosphorous acid salt has been widely used in plant pest control and plant nutrition field abroad, phosphorous acid salt used as a fungicide in the inhibition of Nightshade, brassica and other leafy vegetables and other oomycete bacteria have a good effect.

Action mechanism

Phosphorous acid contains +3-valent phosphorus for dual-channel transport in the xylem and phloem of the crop, accelerating nutrient uptake and utilization; in terms of disease resistance, it is thought that +3-valent phosphorus induces the production of resistance to toxins and disease process-associated proteins (PR proteins), which may depend on salicylic acid (SA) to turn on the defense mechanism for sustained immunity against the pathogen.

Basic information

English name: Phosphorous acid

CAS number: 13598-36-2

Molecular formula: H3PO3

Molecular weight: 82

Density: 1.65g/cm3

UN Number: 2834

EC NO: 237-066-7

Hazard code: 81502

Danger category: 8

Technical index

Phosphorous acid: 98.5-99.0%

PO4≤0.1%

Cl≤0.005%

SO4≤0.0001%

Pb≤0.0002%

Fe≤0.001%

Physical and chemical properties

Appearance: White crystal

Melting point: 73.6℃

Boiling point: 200℃ (decomposition)

Solubility: soluble in water, alcohol, strong hygroscopicity.

Density: 1.65g/cm³

Dangerous characteristics: corrosive, heat decomposition to produce particularly harmful gas H3P.

Product features

1, phosphorous acid has strong hygroscopicity

2, with strong deliquescence

3, has a certain corrosive

4, with bactericidal effect. The salt of phosphite has been shown to have the effect of increasing production and disease resistance of crops.

Production technology

TThe production process of domestic excellent products is mainly PCl3 hydrolysis method. The specific process is as follows:

By hydrolysis method, PCl3 is slowly hydrolyzed with water under stirring, and phosphorous acid is produced. After refining, cooling, crystallization and decolorization, phosphorous acid is produced. Its PCI3+3H2O→H3PO3+3HCl, hydrogen chloride produced in the production process recycling, can be made into hydrochloric acid

Contact storage measures

1, wear protective gloves/wear protective clothing/wear protective eye mask/wear protective mask.

2. Wash skin thoroughly after operation.

3. Store only in the original container. Do not inhale dust or fumes.

4, do not eat, drink or smoke when using this product.

Phosphorous acid may have a corrosive effect on metals, avoid direct contact with the skin and stimulate skin rot, especially avoid contact with the eyes, which can cause serious eye damage. It is used as a reducing agent in chemical reaction, and is relatively mild and controllable in actual reaction. Phosphite is used as raw material for the production of potassium phosphite, potassium dihydrogen phosphite, calcium hydrogen phosphite, in addition to synthetic fiber, pesticide industry, etc.