Sodium persulfate
 Sodium persulfate sample
| |
| Names | |
|---|---|
| IUPAC name
Sodium peroxydisulfate
| |
| Other names
Sodium peroxodisulfate
Sodium peroxodisulphate Sodium peroxydisulphate | |
| Properties | |
| Na2S2O8 | |
| Molar mass | 238.10 g/mol |
| Appearance | White solid |
| Odor | Odorless |
| Density | 2.59 g/cm3 (Loose bulk density: 1.12 g/cm3) |
| Melting point | 180 °C (356 °F; 453 K) (decomposes) |
| Boiling point | Decomposes |
| 55.6 g/100 ml (20 °C) | |
| Vapor pressure | ~0 mmHg |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose)
|
920 mg/kg (rat, female, oral) 930 mg/kg (rat, male, oral) |
| Related compounds | |
| Related compounds
|
Ammonium persulfate Potassium persulfate |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Sodium persulfate is the chemical compound with the formula Na2S2O8, the sodium salt of peroxydisulfuric acid. It is almost non-hygroscopic and has good shelf-life.
Sodium persulfate is preferred by many chemists over other persulfate salts, as it has good solubility in water and long shelf-life, while also having better performance than other persulfate salts.
Contents
Properties
Chemical
Sodium persulfate is an oxidizer. It is a common oxidizing agent in Elbs persulfate oxidation or Boyland–Sims oxidation.
Heating it in solution to 80-90 Celsius for 2-3 minutes in presence of MnO2 leads to a decomposition reaction catalyzed by manganese dioxide:
- 2 Na2S2O8 + 2H2O → 4 NaHSO4 + O2
This reaction can be used as a qualitative test for the peroxodisulfate anion: just heat it with MnO2 and check the pH with a test strip. Low pH means positive test.
Physical
Sodium persulfate is a white solid, soluble in water.
Availability
Sodium persulfate can be bought from various electronic shops, as etching powder for zinc and printed circuit boards, as well as for pickling of copper and some other metals.
Preparation
The salt is prepared by the electrolytic oxidation of sodium bisulfate:
- 2 NaHSO4 → Na2S2O8 + H2
Oxidation is conducted at a platinum anode.
Projects
- PCB etchant
- Make permanganates
- Make benzaldehyde from benzyl alcohol
- Elbs persulfate oxidation
- Boyland–Sims oxidation
Handling
Safety
Sodium persulfate is an oxidizer and forms combustible mixtures with organic materials such as paper.
Storage
In closed plastic or glass bottles.
Disposal
Can be neutralized by heating it, which causes it to decompose.
