Methane Activation with N-Haloimides

Resurgence and advancement of photochemical hydrogen atom transfer processes in selective alkane functionalizations

The selective functionalization of alkanes has long been recognized as a prominent challenge and an arduous task in organic synthesis. Hydrogen atom transfer (HAT) processes enable the direct generation of reactive alkyl radicals from feedstock alkanes and have been successfully employed in industrial applications such as the methane chlorination process, etc. Nevertheless, challenges in the regulation of radical generation and reaction pathways have created substantial obstacles in the development of diversified alkane functionalizations. In recent years, the application of photoredox catalysis has provided exciting opportunities for alkane C-H functionalization under extremely mild conditions to trigger HAT processes and achieve radical-mediated functionalizations in a more selective manner. Considerable efforts have been devoted to building more efficient and cost-effective photocatalytic systems for sustainable transformations. In this perspective, we highlight the recent development of photocatalytic systems and provide our views on current challenges and future opportunities in this field.

Conversion of methane to acetonitrile over GaN catalysts derived from gallium nitrate hydrate co-pyrolyzed with melamine, melem, or g-C3N4: the influence of nitrogen precursors

The GaN catalyst derived from co-pyrolyzing gallium nitrate hydrate and g-C3N4 is effective in the conversion of methane to acetonitrile because of its well dispersed GaN crystals and amorphous CN species.

Synthesis of Methanesulfonic Acid Directly from Methane: The Cation Mechanism or the Radical Mechanism?

In 2019, Diaz-Urrutia and Ott developed a high-yield method for direct conversion of methane to methanesulfonic acid and proposed a cationic chain reaction mechanism. However, Roytman and Singleton questioned this mechanism, and they favored a free-radical mechanism. In the present paper, we studied both the cationic chain and radical mechanisms and found the radical mechanism is more favorable, since it has a much lower energy barrier. However, the radical mechanism has not considered the effect of ions for the reaction taking place in oleum. Thus, we studied a simple model of a protonated radical mechanism, which further lowers the energy barrier. Although the true mechanism for the CH₄ + SO₃ reaction could be more complicated in electrolyte solutions, this model should be helpful for the further study of the mechanism of this reaction.