Methane Sulfonation via a Free-Radical Mechanism by Trifluoroacetylsulfuric Acid
Sungah Kim1, Jen-Chieh Wang1, Joo Ho Lee1
1Loker Hydrocarbon Research Institute, Department of Chemistry, University of Southern California, 837 Bloom Walk, Los Angeles, California 90089, United States.
Abstract:
Using trifluoroacetyl sulfuric acid (TFAOSO3H), we discovered a new methane activation method and revealed its radical pathway under mild conditions. Upon the addition of a radical initiator with methane, the crude solution of TFAOSO3H developed the methyltrifluoroacetylsulfate radical ((TFAO)CH3S(OH)O2•). The resulting (TFAO)CH3S(OH)O2• behaved as a critical radical propagator for carbon-hydrogen bond activation, culminating in successful methane sulfonation. With 9.5 mol % of K2S2O8, TFAOSO3H and methane were selectively converted to methanesulfonic acid in 94 and 86% conversion yields, respectively.
Related Concept Videos
Preparation and Reactions of Sulfides
Electrophilic Aromatic Substitution: Sulfonation of Benzene
Preparation and Reactions of Thiols
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
Radical Anti-Markovnikov Addition to Alkenes: Mechanism
The mechanism starts with chain initiation, which involves two steps. In the first chain initiation step, a weak peroxide bond is homolytically cleaved upon mild heating to form two alkoxy radicals. In the second initiation step, a hydrogen atom is abstracted by the alkoxy...
Radical Substitution: Halogenation of Alkanes and Alkyl Substituents
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...


