Electron-Induced Synthesis of Dimethyl Ether in the Liquid-Vapor Interface of Methanol
Ziyuan Li1, Cen-Feng Fu1, Ziwei Chen1
1Department of Chemical Physics, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China.
Abstract:
Ether synthesis from alcohol is known to be acid-catalyzed. Such a process could happen in the acidified liquid of alcohol, but hitherto lacking the experimental evidence. Here we demonstrate that dimethyl ether is spontaneously synthesized in the liquid-vapor interface of pure methanol after ionizing radiation with electrons. Using time-delayed tandem mass spectrometry measurements in combination with theoretical calculations, we further confirm that the protonated dimethyl ether is produced from the ion-molecule reactions not only in the dense vapor above the interface but also within the molecular clusters of the acidic interface. Our finding provides a convincing piece of evidence about the liquid-vapor interfacial acidification by the electron-impact ionizing radiation, exhibiting a promising way to control the chemical reactions in the liquid surface.
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