2918-13-0Relevant articles and documents
Selective oxidation of styrene catalyzed by cerium-doped cobalt ferrite nanocrystals with greatly enhanced catalytic performance
Tong, Jinhui,Li, Wenyan,Bo, Lili,Wang, Huan,Hu, Yusen,Zhang, Zhixia,Mahboob, Abdulla
, p. 474 - 481 (2016/11/18)
The rare earth metal Ce-doped cobalt ferrite samples CexCo1?xFe2O4 (x?=?0.1, 0.3, 0.5) were prepared by the sol–gel autocombustion route. The as-prepared samples were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, ICP–atomic emission spectroscopy, and N2 physisorption. Their catalytic performance was evaluated in oxidation of styrene using hydrogen peroxide (30%) as oxidant. Compared with pristine CoFe2O4, the Ce-doped samples were found to be more efficient catalysts for the oxidation of styrene to benzaldehyde, with greatly enhanced catalytic performance. Especially, when Ce0.3Co0.7Fe2O4 was used as catalyst, 90.3% styrene conversion and 91.5% selectivity for benzaldehyde were obtained at 90?°C for 9?h reaction. The catalyst can be magnetically separated easily for reuse, and no obvious loss of activity was observed when it was reused in five consecutive runs.
Solid Lewis acids catalyze the carbon-carbon coupling between carbohydrates and formaldehyde
Van De Vyver, Stijn,Odermatt, Caroline,Romero, Kevin,Prasomsri, Teerawit,Román-Leshkov, Yuriy
, p. 972 - 977 (2015/09/08)
The development of catalytic C-C bond formation schemes based on renewable substrates is important for defining sustainable paradigms for chemical manufacturing. With a few exceptions, aldol condensation reactions between biomass-derived platform chemicals have received little attention so far. Here the C-C coupling between 1,3-dihydroxyacetone (DHA) and formaldehyde into α-hydroxy-γ-butyrolactone (HBL) using Sn-Beta is demonstrated. Reactivity studies, coupled with spectroscopic and computational analyses, show that the formation of HBL proceeds by soft enolization of DHA followed by an aldol addition of formaldehyde to the Sn-enolate intermediate, generating erythrulose as an intermediate species. Isotopic labeling is used to reveal the position where formaldehyde is incorporated into HBL, providing further support for our proposed mechanism. Finally, combining the C-C coupling reaction with transfer hydrogenation of formaldehyde has allowed us to expand the substrate scope to include polyols glycerol and ethylene glycol.
Preparation of α-methylene ketones by direct methylene transfer
Rodrigues, J. Augusto R.,Siqueira-Filho, Ezequias P.,De Mancilha, Moacir,Moran, Paulo J. S.
, p. 331 - 340 (2007/10/03)
Four methods for the preparation of α-methylene ketones by direct methylene transfer are presented. The procedures were optimized in order to obtain high yields.
