Dimethyl sulfite

Dimethyl sulfite is a sulfite ester with the chemical formula (CH₃O)₂SO.

Dimethyl sulfite

Names
Preferred IUPAC name Dimethyl sulfite
Other names Dimethyl sulphite Sulfurous acid, dimethyl ester DMSO3[1]
Identifiers
CAS Number	616-42-2 Y
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:48858 Y
ChemSpider	62436 Y
ECHA InfoCard	100.009.529
EC Number	210-481-0
PubChem CID	69223
UNII	9JFA40S66P Y
CompTox Dashboard (EPA)	DTXSID3060665
InChI InChI=1S/C2H6O3S/c1-4-6(3)5-2/h1-2H3 Y Key: BDUPRNVPXOHWIL-UHFFFAOYSA-N Y InChI=1/C2H6O3S/c1-4-6(3)5-2/h1-2H3 Key: BDUPRNVPXOHWIL-UHFFFAOYAF
SMILES COS(=O)OC O=S(OC)OC
Properties
Chemical formula	C2H6O3S
Molar mass	110.13 g·mol−1
Appearance	Clear liquid
Density	1.29 g/cm3
Boiling point	126 °C (259 °F; 399 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Dimethyl sulfite is used as an additive in some polymers to prevent oxidation.^[2] It is also a potentially useful high energy battery electrolyte solvent.^[3]

Structure and conformation

The dimethyl sulfite molecule can adopt several conformations. The most stable is the GG conformer.^[1] Each C–O bond is gauche to the S=O bond, depicted below.

Preparation

Dimethyl sulfite is prepared from a 1:2 ratio of thionyl chloride and methanol.^[4] The reaction can be catalyzed by tertiary amine bases and likely proceeds via the chlorosulfinate (MeOS(O)Cl),^[5] this intermediate will exist only fleetingly in the presence of methanol and as such its decomposition to methyl chloride and sulfur dioxide (via the slower SNi mechanism) is not observed to any great extent.

SOCl₂ + 2 CH₃OH → (CH₃O)₂SO + 2 HCl

See also

• Methyl methanesulfonate, chemical isomer
• Diethyl sulfite, a similar sulfite ester
• Dimethyl sulfoxide
• Dimethyl sulfate, a sulfate ester