Hydrogen peroxide

 

Hydrogen peroxide

Chemical formula	H2O2
OTP appearance	colorless liquid
Molar Mass(g/mol)	34
Density(g/cc)	1.135
Melting Point(°C)	-0.43
Boiling Point(°C)	150
NFPA 704	0 3 2 ox

Uses

Justification Questioned

Other

• Aids in the production of nitric and sulfuric acids.
• Combined with sulfuric acid produces pirahna solution useful in metal extraction
• Rapidly catalyzed decomposition is enormously exothermic and can be used as rocket fuel, etc
• A potent oxidizer used to convert halide ions to halide molecules
• Pharm: rapid injection into puncture wounds prevents tetanus.

Natural Occurrence

• Does occur naturally in very tiny amounts in plants and animals.

Hazards

• Contact with metals can result in a self-catalyzing decomposition, producing a lot of thermal energy and and abundance of gaseous pxygen: A bad combination.

  2 H₂O₂

  {Ag

  →

  }

  2 H₂O + O₂

• Contact with organics can result in sensitive (primary-explosive) organic peroxides

  e.g. TATP

Production

Synthesis

Barium Peroxide

phosphoric acid

• Combine barium peroxide with phosphoric acid giving barium phosphate and hydrogen peroxide.

  3 BaO₂ + 2 H₃PO₄ → Ba₃(PO₄)₂ + 3 H₂O₂

sulfuric acid

• Combine barium peroxide with sulfuric acid, precipitating barium sulfate and hydrogen peroxide.

  BaO₂ + H₂SO₄ → BaSO₄ + H₂O₂

• Would hydrogen sulfide work as well?

  BaO₂ + H₂S → BaS + H₂O₂ // ???

Sodium peroxide

• Combine sodium peroxide with 20% sulfuric acid kept below 10°C

  Na₂O₂ + H₂SO₄ → H₂O₂ + Na₂SO₄

• Combine sodium peroxide with water, forming sodium hydroxide and hydrogen peroxide

  Na₂O₂ + 2 H₂O → 2 NaOH + 2 H₂O₂

• Would hydrogen sulfide work as well?

  Na₂O₂ + H₂S → Na₂S + H₂O₂ // ???

Electrolysis

Electrolysis of a chilled (10°C) acidic (H₂SO₄) solution of ammonium bisulfate produces ammonium persulfate and hydrogen, which escapes. The persulfate decomposes to hydrogen peroxide and sulfuric acid, which recombines with the ammonium cations to reconstitute the original ammonium bisulfate.

2 NH₄HSO₄ → (NH₄)₂S₂O₈ + H₂

(NH₄)₂S₂O₈ + 2 H₂O → 2 NH₄HSO₄ + H₂O₂

NET: 2 H₂O → H₂O₂ + H₂

Purification

1. Prepare a saturated solution of barium hydroxide
2. Add dilute hydrogen peroxide, precipitating a stochiometric amount of barium peroxide

   Ba(OH)₂ + H₂O₂ → BaO₂(s) + 2 H₂O

3. Filter and discard filtrate, retaining the residue of barium peroxide
4. Add filtrate to concentrated sulfuric acid, producing concentrated hydrogen peroxide and barium sulfate

   BaO₂ + H₂SO₄ → BaSO₄ + H₂O₂

   Would hydrogen sulfide work as well?

   BaO₂ + H₂S → BaS + H₂O₂ // would this work?

Storage

• It can be "stored" in solid form in percarbonates and perborates and quickly reconstituted by heating.
• aqueous concentrations below 5% can be stored in normal plastic and glass containers
• aqueous concentrations of 30% or higher must take great care to exclude metal and organic debris in the container. Metals can catalyze decomposition and organics can form very sensitive (primary explosive) peroxides.