title: Acid-Base Pairs in Lewis Acidic Zeolites Promote Direct Aldol Reactions by Soft Enolization.
abstract: Hf-, Sn-, and Zr-Beta zeolites catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft enolization through α-proton abstraction. The Lewis acidic zeolites maintain activity in the presence of water and, unlike traditional base catalysts, in acidic solutions.
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (USA) http://www.romangroup.mit.edu.
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Lewis
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (USA) http://www.romangroup.mit.edu.
authors.forename: Stijn
authors.initials: S
authors.lastname: Van de Vyver
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (USA) http://www.romangroup.mit.edu. yroman@mit.edu.
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Román-Leshkov
mesh_terms: D000096:Acetone / Q000737:chemistry*; D000136:Acid-Base Equilibrium; D000447:Aldehydes / Q000737:chemistry*; D002384:Catalysis; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry; D058116:Lewis Acids / Q000737:chemistry*; D015394:Molecular Structure; D017641:Zeolites / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D007659:Ketones; D058116:Lewis Acids; D017641:Zeolites; D000096:Acetone
keywords: CC coupling; Lewis acids; aldol reaction; heterogeneous catalysis; zeolites