title: Direct and Efficient Dehydrogenation of Tetrahydroquinolines and Primary Amines Using Corona Discharge Generated on Ambient Hydrophobic Paper Substrate.
abstract: The exposure of an aqueous-based liquid drop containing amines and graphite particles to plasma generated by a corona discharge results in heterogeneous aerobic dehydrogenation reactions. This green oxidation reaction occurring in ambient air afforded the corresponding quinolines and nitriles from tetrahydroquinolines and primary amines, respectively, at >96% yields in less than 2 min of reaction time. The accelerated dehydrogenation reactions occurred on the surface of a low energy hydrophobic paper, which served both as container for holding the reacting liquid drop and as a medium for achieving paper spray ionization of reaction products for subsequent characterization by ambient mass spectrometry. Control experiments indicate superoxide anions (O2•-) are the main reactive species; the presence of graphite particles introduced heterogeneous surface effects, and enabled the efficient sampling of the plasma into the grounded analyte droplet solution. Graphical Abstract ᅟ.
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Davis
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA. badu-tawiah.1@osu.edu.
authors.forename: Abraham K
authors.initials: AK
authors.lastname: Badu-Tawiah
keywords: Aerobic oxidation; Corona discharge; Heterogeneous dehydrogenation; Mass spectrometry; Paper spray ionization; Quinoline synthesis