Selective liquid phase oxidation of o-xylene with gaseous oxygen by transition metal containing polysiloxane initiator/catalyst systems

The selective liquid phase oxidation of o-xylene over hydrophobic porous Co(2+) and Mn(3+) containing polysiloxane catalysts showed that both catalysts had higher activity than the homogeneous benchmark system Co naphthenate. The solid catalyst/initiator systems accelerate the radical initiation and the hydroperoxide decomposition. 2-Methylbenzyl hydroperoxide plays a key role in the reaction network as it is the first observed intermediate and is efficiently decomposed by the catalysts. The selectivity of the hydroperoxide decomposition can be controlled to some extent by the choice of transition metal. Co(2+) enhances the formation of o-tolualdehyde, while Mn(3+) increases the tendency to 2-methylbenzyl alcohol formation. The hydrophobic character, demonstrated by the weak adsorption of water, retards the interaction with the polar reaction products and allows their fast desorption, which in turn is a major cause for the high catalytic activity. (C) 2011 Elsevier Inc. All rights reserved.     «

The selective liquid phase oxidation of o-xylene over hydrophobic porous Co(2+) and Mn(3+) containing polysiloxane catalysts showed that both catalysts had higher activity than the homogeneous benchmark system Co naphthenate. The solid catalyst/initiator systems accelerate the radical initiation and the hydroperoxide decomposition. 2-Methylbenzyl hydroperoxide plays a key role in the reaction network as it is the first observed intermediate and is efficiently decomposed by the catalysts. The sel...     »

ISI Document Delivery No.: 831CN Times Cited: 4 Cited Reference Count: 37 Foerster, Tobias Schunk, Stephan A. Jentys, Andreas Lercher, Johannes A. Jentys, Andreas/D-4622-2009 Jentys, Andreas/0000-0001-5877-5042 German Bundesministerium fur Bildung und Forschung (BMBF) [03X2007A] The authors thank the German Bundesministerium fur Bildung und Forschung (BMBF) for partial financial support of the presented work (Project No. 03X2007A). We are very grateful to Dipl. Ing. M. Neukamm for conducting AAS measurements, Dip]. Ing. X. Hecht for operational support, and S. Pedron for experimental help. Furthermore, the authors acknowledge fruitful discussions in the framework of the network of excellence IDECAT. 4 Academic press inc elsevier science San diego     «

ISI Document Delivery No.: 831CN Times Cited: 4 Cited Reference Count: 37 Foerster, Tobias Schunk, Stephan A. Jentys, Andreas Lercher, Johannes A. Jentys, Andreas/D-4622-2009 Jentys, Andreas/0000-0001-5877-5042 German Bundesministerium fur Bildung und Forschung (BMBF) [03X2007A] The authors thank the German Bundesministerium fur Bildung und Forschung (BMBF) for partial financial support of the presented work (Project No. 03X2007A). We are very grateful to Dipl. Ing. M. Neukamm for conducting AAS...     »