Sodium phosphinate (NaPO 2 H 2 , also known as sodium hypophosphite) is the sodium salt of hypophosphoric acid and is often found as NaPO 2 H 2 · H 2 O monohydrate. It is a solid substance that is odorless white crystals at room temperature. It decomposes on heating above 260 ° C.
It absorbs moisture from air, and is readily soluble in water; in an aqueous solution it decomposes when heated (2NaH 2 PO 2 → NaHPO 4 + PH 3 ), releasing hydrogen peroxide. Sodium hypophosphite should be stored in a cool, dry place, isolated from oxidizing agents. It decomposes into phosphine, which irritates the respiratory tract, and disodium phosphate.
Characteristics
Molar mass | 87.96 g / mol |
The physical state | determined by |
density | 1.77 g / cm³ |
melting point | 310 ° C (decomposition of monohydrate) |
solubility | 744 g / l at 20 ° C Soluble in ethanol |
Getting
- You can get it in the following way:
- Sodium phosphinate can be obtained by the reaction of white phosphorus with caustic soda: P 4 + 3NaOH + 3H 2 O → Na 2 NRA 4 + PH 3 ↑ (synthesis of sodium hypophosphite, formula).
- Oxidation of phosphine by sodium hypochlorite: pH 3 + 2NaClO + NaOH → Na (pH 2 O 2 ) + 2NaCl + H 2 O.
- Decomposition of calcium phosphinate with sodium carbonate: Ca (pH 2 O 2 ) + NaOH → Na (pH 2 O 2 ) + CaCO 3 ↓.
- It can be prepared by neutralizing hypophosphoric acid or a solution of calcium phosphinate sodium carbonate: H (PH 2 O 2 ) + NaOH → Na (PH 2 O 2 ) + H 2 O.
A monohydrate is formed in the reaction in aqueous solutions.
Using
Application area:
- Sodium Hypophosphite (SHP) acts as a reducing agent to supply the electrons needed for the EN process. The EN process allows you to get a uniform coating thickness not only on metal objects, but also on plastic and ceramics. Using this method, a long-lasting nickel-phosphorus film can cover uneven surfaces, for example, in avionics, aviation and in oil fields. SHP is capable of reducing nickel ions in solution to metallic nickel on metal substrates, as well as on plastic substrates. The latter requires that the substrate be activated by small particles of palladium. As a result, the nickel deposit contains up to 15% phosphorus.
- As a raw material in the production of other products, including hypophosphorous acid. It can be used in synthetic organic chemistry, especially in deamination by reduction of diazo derivatives.
- SHP can be used as a reducing agent or antioxidant in chemical processing.
- SHP is used as a stabilizer to prevent polymer degradation during extrusion or other hot processing.
- Sodium phosphinate is used as a Thiele reagent to detect selenium.
- Sodium hypophosphite can be used as a partial flame retardant. This will provide a source of electrons in the regeneration of the resin.
- Polymerization catalyst.
- Polymer stabilizer.
Health effects
Allergic skin reactions may occur in some people after repeated exposure to sodium hypophosphite on the skin. Additional data on the ability to cause toxic effects in humans are not available. It does not cause skin or eye irritation in laboratory animals. No toxic effects were observed with oral use or moderate to high skin exposure.
A decrease in activity was observed in laboratory animals exposed to extremely high oral doses of sodium hypophosphite. Some animals died. No signs of infertility, abortion, or birth defects were observed in laboratory animals after oral exposure before and / or during pregnancy. There are no data on the ability to cause cancer in laboratory animals. The potential for sodium hypophosphite to cause cancer in humans has not been evaluated. Nevertheless, it is recommended to use protective equipment when working with the substance.