Sodium permanganate

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Sodium permanganate
Names
IUPAC name
Sodium manganate(VII)
Other names
Permanganate of sodium
Properties
NaMnO4 (ahydrous)
NaMnO4·H2O (monohydrate)
Molar mass 141.9254 g/mol (anhydrous)
159.94 g/mol (monohydrate)
Appearance Red-purple solid
Odor Odorless
Density 1.972 g/cm3 (monohydrate)
Melting point 170 °C (338 °F; 443 K) (trihydrate)
Boiling point Decomposes
90 g/100 ml
Solubility Readily soluble in acetone[1]
Vapor pressure ~0 mmHg
Hazards
Safety data sheet Spectrum (monohydrate)
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
9,000 mg/kg (rat, oral)
Related compounds
Related compounds
Ammonium permanganate
Potassium permanganate
Barium permangnate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium permanganate is a chemical compound with the formula NaMnO4, more commonly encountered as monohydrate. It is closely related to the more common potassium permanganate, though it's not as often encountered.

Properties

Chemical

Sodium permanganate is a strong oxidizer.

Addition of conc. sulfuric acid will yield manganese heptoxide.

Physical

Sodium permangate is a red or purplish solid, very soluble in water.

Availability

Sodium permangante is sometimes sold by chemical suppliers.

Preparation

Sodium permanganate can be easily prepared by reacting a mixture of sodium hypochlorite and sodium hydroxide, with freshly prepared manganese dioxide.

2 MnO2 + 3 NaOCl + 2 NaOH → 2 NaMnO4 + 3 NaCl + H2O

While easy to do, this reaction will only give small amounts of sodium permanganate, as during the process most of the hypochlorite decomposes.

Electrolysis of a solution of 5-20% NaOH using manganese metal will give sodium permanganate.[2] Sodium carbonate can also be used.[3]

The substitution reaction between sodium sulfate and calcium or barium permanganate will also give sodium permanganate. This route is attractive due to the very high solubility of sodium permanganate. However, due to the poor solubility of the precursors, this process may take a while.

A less known route involves the addition of calcium hypochlorite and sodium hydroxide to a concentrated solution of manganese(II) chloride. The resulting product is heated on a steam bath, then purified. The resulting sodium permanganate solution is determined to be fairly concentrated. While it was believed that the permanganate from this route was obtained from the chlorate derived from the decomposition of the hypochlorite during heating, a repeat of this method using potassium chlorate gave no permanganate.[4]

Sodium permanganate cannot be prepared analogously to the route to KMnO4 because the required intermediate manganate salt, Na2MnO4, is unstable and does not form.

Projects

  • Oxidizer
  • Make manganese heptoxide

Handling

Safety

Sodium permangante is a strong oxidizer and should be handled with proper protection.[5]

Storage

In airtight containers.

Disposal

Can be neutralized with hydrogen peroxide, resulting sodium hydroxide and manganese dioxide. The latter can be recycled through sedimentation or filtration.

References

  1. Grimm, H. G.; Peters, C.; Wolff, H.; Zeitschrift fuer Anorganische und Allgemeine Chemie; vol. 236; (1938); p. 57 - 77
  2. Zaretskii, S. A.; Zharnitskii, I. G.; Bogdanova, I. A.; Soviet Electrochem. Proc. 4th Conf. Electrochem., Moscow 1956 (1959), New York 1961, Bd. III, pp. 110/3
  3. Agladze, R. I.; Domanskaya, G. M.; Zhurnal Prikladnoi Khimii (Sankt-Peterburg, Russian Federation); vol. 24; (1951);
  4. Baxter, G. P.; Frevert; American Chemical Journal; vol. 34; (1905); p. 114 - 114
  5. https://cameochemicals.noaa.gov/chemical/1515

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