Methanesulfonic acid

Methanesulfonic acid
IUPAC name Methanesulfonic acid
Other names Methylsulfonic acid, MSA
Identifiers
CAS number	75-75-2 Y
PubChem	6395
ChemSpider	6155 Y
UNII	12EH9M7279 Y
EC number	200-898-6
ChEBI	CHEBI:27376 Y
Jmol-3D images	Image 1
SMILES O=S(=O)(O)C
InChI InChI=1S/CH4O3S/c1-5(2,3)4/h1H3,(H,2,3,4) Y Key: AFVFQIVMOAPDHO-UHFFFAOYSA-N Y InChI=1/CH4O3S/c1-5(2,3)4/h1H3,(H,2,3,4)/f/h2H InChI=1/CH4O3S/c1-5(2,3)4/h1H3,(H,2,3,4) Key: AFVFQIVMOAPDHO-UHFFFAOYAS
Properties
Molecular formula	CH4O3S
Molar mass	96.11 g mol−1
Density	1.48 g/cm3
Melting point	17-19 °C
Boiling point	167 ºC /10 mmHg, 122 ºC/1 mmHg
Acidity (pKa)	-1.9[1]
Hazards
MSDS	Oxford MSDS
EU classification	Harmful (Xn), Corrosive (C)
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Methanesulfonic acid is a colorless liquid with the chemical formula CH₃SO₃H. It is the simplest of the alkylsulfonic acids. Salts and esters of methanesulfonic acid are known as mesylates. Methanesulfonic acid is used as an acid catalyst in organic reactions because it is non-volatile, strong acid that is soluble in organic solvents. Methanesulfonic acid is convenient for industrial applications because it is liquid at ambient temperature, while the closely related p-toluenesulfonic acid (PTSA) is solid. However, in a laboratory setting, solid PTSA is more convenient.

Methanesulfonic acid may be considered an intermediate compound between sulfuric acid (H₂SO₄), and methylsulfonylmethane ((CH₃)₂SO₂), effectively replacing an -OH group with a -CH₃ group at each step. This pattern can extend no further in either direction without breaking down the -SO₂ group.

Methanesulfonic acid can be used in the generation of borane (BH₃). By reacting methanesulfonic acid with NaBH₄ in an aprotic solvent such as THF or DMS, the complex of BH₃ and the solvent is formed.^[2]

Applications

• Flow batteries ^[3]

References

1. ^ Guthrie, J. P. Hydrolysis of esters of oxy acids: pKa values for strong acids. Can. J. Chem. 1978, 56, 2342-2354.
2. ^ Lobben, Paul C.; Leung, Simon Shun-Wang; Tummala, Srinivas (2004). "Integrated Approach to the Development and Understanding of the Borane Reduction of a Carboxylic Acid". Org. Proc. Res. Dev. 8: 1072. doi:10.1021/op049910h. 
3. ^ http://plurionsystems.com/tech_flow_technology.html