Peroxydisulfuric acid

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Peroxydisulfuric acid
Names
IUPAC name
Peroxydisulfuric acid
Other names
Marshall's acid
Peroxodisulfuric acid
Persulfuric acid
μ-peroxido-bis(hydroxidodioxidosulfur)
Properties
H2S2O8
Molar mass 194.143 g/mol
Appearance Colorless solid
Odor Odorless
Melting point 65 °C (149 °F; 338 K) (decomposes)
Boiling point Decomposes
Soluble
Solubility Reacts with amines
Soluble in alcohols (reacts)
Insoluble in ether
Hazards
Safety data sheet None
Flash point Non-flammable
Related compounds
Related compounds
Sulfuric acid
Peroxymonosulfuric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Peroxydisulfuric acid or Marshall's acid, is a chemical compound, a strong oxoacid with the chemical formula H2S2O8. The free acid is not used in chemistry, but it's salts are more often encountered.

Properties

Chemical

Peroxydisulfuric acid will react violently with many organic compounds.

Hydrolysis of peroxydisulfuric acid produces hydrogen peroxide and sulfuric acid:

H2S2O8 + 2 H2O → 2 H2SO4 + H2O2

Partial hydrolysis of peroxydisulfuric acid produces peroxymonosulfuric acid and sulfuric acid.

H2S2O8 + H2O → H2SO5 + H2SO4

Physical

Peroxydisulfuric acid is a hygroscopic colorless solid, that is soluble in water.

Availability

The pure acid is not sold, instead its salts are more readily available.

Preparation

Can be prepared by adding concentrate sulfuric acid to sodium persulfate.

The acid can also be prepared by the reaction of chlorosulfuric acid with hydrogen peroxide.[1]

2 ClSO3H + H2O2 → H2S2O8 + 2 HCl

Projects

  • Make persulfate salts

Handling

Safety

Peroxydisulfuric acid is highly corrosive and may explode in contact with organic substances.

Storage

Peroxydisulfuric acid is not very stable, but at least one source claims it can be kept relative stable at low temperatures, for up to 8 weeks.[2]. Aqueous solutions of this acid are more stable at 0-17 °C.[3]

Peroxoacids should not be stored, as they will react violently with anything organic (dust, particulates, hair strands, etc.).

Disposal

Should be dissolved in water and neutralized with a reducing agent and a base.

References

  1. https://onlinelibrary.wiley.com/doi/abs/10.1002/14356007.a19_177.pub2
  2. D'Ans, J.; Zeitschrift fuer Elektrochemie; vol. 17; (1911); p. 849 - 851
  3. Elbs, K.; Schoenherr, O.; Zeitschrift fuer Elektrochemie; vol. 1; (1894); p. 468 - 472,

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