Trimethyloxonium tetrafluoroborate

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Trimethyloxonium tetrafluoroborate
Structural formula of trimethyloxonium tetrafluoroborate
Ball-and-stick models of the component ions of trimethyloxonium tetrafluoroborate
IUPAC name
Trimethyloxonium tetrafluoroborate
Other names
Trimethyloxonium fluoborate
3D model (JSmol)
ECHA InfoCard 100.006.360
Molar mass 147.91 g·mol−1
Melting point 179.6–180 °C (355.3–356.0 °F; 452.8–453.1 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Trimethyloxonium tetrafluoroborate is the organic compound with the formula Me3OBF4. It is sometimes called the "Meerwein salt" after Hans Meerwein.[1]) This salt is a strong methylating agent, being a source of CH3+. It is a white solid. Triethyloxonium tetrafluoroborate is a closely related reagent.

Preparation and reactions[edit]

The compound is prepared by the reaction of boron trifluoride with dimethyl ether and epichlorohydrin:[1]

4 Me2O·BF3 + 2 Me2O + 3 C2H3(O)CH2Cl → 3 Me3O+BF
+ B[(OCH(CH2Cl)CH2OMe]3

The salt hydrolyzes readily:

Me3OBF4 + H2O → Me2O + MeOH + HBF4

Trimethyloxonium tetrafluoroborate is often ranked as the strongest reagent for the electrophilic methylation.[2]


  1. ^ a b T. J. Curphey (1988). "Trimethyloxonium Tetrafluoroborate". Org. Synth. ; Coll. Vol., 6, p. 1019 
  2. ^ Stang, Peter J.; Hanack, Michael; Subramanian, L. R. (1982). "Perfluoroalkanesulfonic Esters: Methods of Preparation and Applications in Organic Chemistry". Synthesis. 1982 (02): 85–126. ISSN 0039-7881. doi:10.1055/s-1982-29711.