Rongalite
From Wikipedia, the free encyclopedia
| Rongalite | |
|---|---|
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| IUPAC name | Sodium hydroxymethanesulfinate |
| Other names | Rongalite Sodium formaldehydesulfoxylate |
| Identifiers | |
| CAS number | [149-44-0] [6035-47-8] dihydrate |
| RTECS number | PB0380000 |
| SMILES | C(O)S(=O)[O-].[Na+] |
| Properties | |
| Molecular formula | CH3NaO3S |
| Molar mass | 118.10 g/mol 154.14 g/mol, dihydrate |
| Appearance | colorless crystals |
| Density | 1.75 g/cm3, dihydrate |
| Melting point |
64.5 °C, dihydrate |
| Solubility in water | 600 g/L, dihydrate (approximate) |
| Acidity (pKa) | decomp. at low pH |
| Structure | |
| Molecular shape | pyramidal at S |
| Hazards | |
| Main hazards | non-toxic |
| R/S statement | R: 36/37/38 S:26-36 |
| Related compounds | |
| Related compounds | SO32-, CH2O |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Rongalite, also called Rongalit (registered trademark of BASF) is sodium hydroxymethylsulfinate, or Na+HOCH2SO2-. The salt has many names, including also sodium formaldehyde sulfoxylate and Bruggolite. It is water-soluble and generally sold as the dihydrate.
Contents |
[edit] Reactions
This salt is prepared from sodium dithionite:
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- Na2S2O4 + 2 CH2O + H2O → NaHOCH2SO3 + NaHOCH2SO2
This reaction proceeds quantitatively, such that dithionite can be determined by its conversion to rongalite, which is far less O2-sensitive and thus easier to handle.
NaHOCH2SO2 can essentially be considered to be a source of SO22-. As such it is used both as a reducing agent and as a reagent to introduce SO2 groups into organic molecules. Treatment of elemental Se and Te with NaHOCH2SO2 gives solutions containing the corresponding Na2Sex and Na2Tex, where x is approximately 2. As a nucleophile, NaHOCH2SO2 reacts with alkylating agents to give sulfones.
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- NaHOCH2SO2 + 2 C6H5CH2Br → [C6H5CH2]2SO2 + NaBr + CH2O + HBr
Occasionally, alkylation will occur also at oxygen, thus α,α' dibromoxylene gives both the sulfone and the isomeric sulfinate ester.
[edit] Use
The original use of the compound was as industrial bleaching agent and in textile dying. The other dominating use today is the application as reducing agent in redox-initiator systems for emulsion polymerization.
[edit] Zinc formaldehyde sulfoxylate
The zinc complex Zn(HOCH2SO2]2 is marketed under the trademarks Decroline, Decolin, and Safolin. This compound is an additive in polymers and textiles.[1]
[edit] References
- ^ Masciocchi, N.; Rigamonti, C. and Maspero, A., "Poly[di-μ3-hydroxymethanesulfinato-zinc(II)]", Acta Crystallographica Section E: Structure Reports Online, 2005, volume E61, m2683-m2685.
- Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- L. Tschugaeff und W. Chlopin: Beiträge zur Kenntnis des Reduktionsvermögens der schwefligen Säure. I. Einwirkung von Natriumhydrosulfit auf Tellur und Selen" Chemische Berichte 1914, volume 47, pages 1269-1275.
- R. Steudel, V. Munchow "Determination of dithionite (S2O22- and Hydroxymethanesulphinate (HOCH2SO2-; Rongalite) by Ion-Pair Chromatography" Journal of Chromatography, (1992) volume 623 174-I 77.
