Methanesulfonic anhydride

Methanesulfonic anhydride is the acid anhydride of methanesulfonic acid. Like methanesulfonyl chloride, it may be used to generate mesylates (methanesulfonyl esters). It is commercially available but may also be prepared by the reaction of phosphorus pentoxide with methanesulfonic acid at 80 °C.

2 P₂O₅ + 6 CH₃SO₃H → 3 (CH₃SO₂)₂O + 4 H₃PO₄