Back Cover: The Role of Hydroxyl Group Acidity on the Activity of Silica-Supported Secondary Amines for the Self-Condensation of n-Butanal (ChemSusChem 3/2015)



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The Back Cover picture shows the utility of mesoporous silica-supported secondary amine catalysts for the sustainable production of diesel fuel or additives from biomass-derived platform molecules. As fermentation products possess lower carbon numbers coupling chemistry is needed to design larger molecules. To realize selective coupling, we developed a highly efficient solid-base organocatalyst for the self-condensation of n-butanal to 2-ethylhexenal by grafting site-isolated amines on tailored silica surfaces. The spacing between the amines and M-OH groups (M=Al, Ti, Zr, Sn) is crucial to maximize their co-operative action and to minimize acid–base neutralization. The catalytic activity can be significantly altered by controlling the Brønsted acidity of the M-OH species. More details can be found in the Full Paper by Shylesh et al. on page 466 (DOI: 10.1002/cssc.201402443).