title: On the chemistry of ethanol on basic oxides: revising mechanisms and intermediates in the Lebedev and Guerbet reactions.
abstract: A common way to convert ethanol into chemicals is by upgrading it over oxide catalysts with basic features; this method makes it possible to obtain important chemicals such as 1-butanol (Guerbet reaction) and 1,3-butadiene (Lebedev reaction). Despite their long history in chemistry, the details of the close inter-relationship of these reactions have yet to be discussed properly. Our present study focuses on reactivity tests, in situ diffuse reflectance infrared Fourier transform spectroscopy, MS analysis, and theoretical modeling. We used MgO as a reference catalyst with pure basic features to explore ethanol conversion from its very early stages. Based on the obtained results, we formulate a new mechanistic theory able to explain not only our results but also most of the scientific literature on Lebedev and Guerbet chemistry. This provides a rational description of the intermediates shared by the two reaction pathways as well as an innovative perspective on the catalyst requirements to direct the reaction pathway toward 1-butanol or butadiene.
authors.affiliation: Dipartimento di Chimica Industriale "Toso Montanari", Alma Mater Studiorum Università di Bologna, Viale del Risorgimento, 4, 40136 Bologna (Italy); CIRI Energia e Ambiente, Alma Mater Studiorum Università di Bologna.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Chieregato
authors.forename: Juliana
authors.initials: J
authors.lastname: Velasquez Ochoa
authors.forename: Claudia
authors.initials: C
authors.lastname: Bandinelli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Fornasari
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Cavani
authors.forename: Massimo
authors.initials: M
authors.lastname: Mella
mesh_terms: D002384:Catalysis; D000431:Ethanol / Q000737:chemistry*; D006865:Hydrogenation; D008277:Magnesium Oxide / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D008277:Magnesium Oxide; D000431:Ethanol
keywords: alcohols; alkenes; density functional calculations; magnesium; reaction mechanisms