Solvent-Induced Reversal of Activities between Two Closely Related Heterogeneous Catalysts in the Aldol Reaction

TitleSolvent-Induced Reversal of Activities between Two Closely Related Heterogeneous Catalysts in the Aldol Reaction
Publication TypeJournal Article
Year of Publication2013
AuthorsKandel K, Althaus SM, Peeraphatdit C, Kobayashi T, Trewyn BG, Pruski M, Slowing II
Journal TitleACS Catalysis
Volume3
Pages265-271
Date Published02
Type of ArticleArticle
ISBN Number2155-5435
Accession NumberWOS:000314557900022
KeywordsACID, aldol condensation, asymmetric aldol, c-13 nmr, condensation-reactions, enamine catalysis, iminium catalysis, mesoporous silica, mesoporous silica nanoparticles, primary amine catalysts, proline, solid-state, solid-state nmr, solvent effects, water
Abstract

The relative rates of the aldol reaction catalyzed by supported primary and secondary amines can be inverted by 2 orders of magnitude, depending on the use of hexane or water as a solvent. Our analyses suggest that this dramatic shift in the catalytic behavior of the supported amines does not involve differences in reaction mechanism, but is caused by activation of imine to enamine equilibria and stabilization of iminium species. The effects of solvent polarity and acidity were found to be important to the performance of the catalytic reaction. This study highlights the critical role of solvent in multicomponent heterogeneous catalytic processes.

URL<Go to ISI>://WOS:000314557900022
DOI10.1021/cs300748g