1686-14-2Relevant academic research and scientific papers
Growth of Cu-BTC MOFs on dendrimer-like porous silica nanospheres for the catalytic aerobic epoxidation of olefins
Zhou, Zihao,Li, Xiujuan,Wang, Yulin,Luan, Yi,Li, Xiaoyu,Du, Xin
, p. 14350 - 14357 (2020)
The composition of metal-organic frameworks (MOFs) and porous carriers can be utilized for a variety of material applications. In this study, DPSNs@Cu-BTC nanocomposites are achieved utilizing Dendrimer-like Porous Silica Nanoparticles (DPSNs) as the support through a template-mediated self-assembly mechanism. The fabrication process is initiated from the controllable growth of Cu2O nanoparticles (NPs) in the center-radial porous channels of DPSNs, which forms DPSNs@Cu2O nanocomposites. Under the protection of DPSNs, the loaded Cu2O NPs gradually dissolved in the weak acid solution, thus providing copper ions to guide the formation and growth of Cu-BTC nanocrystals. Moreover, the Cu-BTC NPs were restricted in the center-radial porous channels of the DPSNs, thus resulting in small sizes and a uniform distribution. The formation of the DPSNs@Cu-BTC nanocomposites with adjustable amounts of Cu-BTC mainly depended on the amounts of Cu2O NPs loaded and the amount of organic ligands added. Furthermore, the nanocomposite exhibited high catalytic performance and good recyclability taking advantage of the uniform loading of small-sized Cu-BTC NPs in the accessible center-radial porous channels of the DPSNs. This new design of DPSNs@Cu-BTC provided a new approach for the synthesis of various MOF-based nanocomposites with improved performance.
An Organotin Vanadate with Sodalite Topology and Catalytic Versatility in Oxidative Transformations
Gomes, Ana C.,Antunes, Margarida M.,Abrantes, Marta,Valente, Anabela A.,Paz, Filipe A. Almeida,Gon?alves, Isabel S.,Pillinger, Martyn
, p. 3481 - 3489 (2018)
The new coordination polymer formulated as [Et3SnVO3] (1) has been synthesized and shown by a combined single-crystal and synchrotron powder X-ray diffraction structural analysis, supported by solid-state NMR, to possess a three-dimensional network structure with the sodalite topology, formed by tetravanadate polyanions, [V4O12]4?, that are linked by Et3Sn+ spacers. The catalytic versatility of compound 1 for liquid phase organic reactions was demonstrated by applying it for the epoxidation of olefins, the oxidative dehydrogenation of alcohols, and the oxidation of benzyl alcohol to benzaldehyde and benzoic acid, using tert-butyl hydroperoxide (TBHP) as oxidant. Compound 1 acts a solid reservoir for soluble, catalytically active species, which promote high selectivities to the epoxide and carbonyl (aldehyde/ketone/acid) products. The epoxidation activity compares favorably with those reported for other organotin molybdate, tungstate and vanadate coordination polymers, and is superior to that displayed by the starting materials used for its synthesis (Et3SnBr and NH4VO3) and the metavanadate NBu4VO3.
Molecular structure-activity relationships for the oxidation of organic compounds using mesoporous silica catalysts derivatised with bis(halogeno)dioxomolybdenum(VI) complexes
Nunes, Carla D.,Valente, Anabela A.,Pillinger, Martyn,Rocha, Joao,Goncalves, Isabel S.
, p. 4380 - 4390 (2003)
Mo K-edge XAFS spectra have been measured for ordered mesoporous silica MCM-41 grafted with the complexes [MoO2X2(thf) 2] (X = Cl, Br). For grafting reactions in the absence of triethylamine, materials with 1 wt.% Mo are obtained; the Mo K-edge EXAFS results indicate the co-existence of isolated surface-fixed monomeric species {MoO2[(-O)3SiO]2(thf)n} and {MoO2[(-O)3SiO]X(thf)n}. When Et3N is used in the grafting reactions, materials with 4 wt. % Mo are obtained. The EXAFS data for the material prepared using [MoO2Cl 2(thf)2] and Et3N indicate the presence of dinuclear species with two MoVI centres, each with two Mo=O groups and each linked by one or two oxo bridges (Mo...Mo 3.27 A). The molybdenum centres in the material prepared using the dibromo complex comprise mainly isolated four-coordinate dioxomolybdenum(VI) and trioxomolybdenum(VI) monomeric species, with a small contribution from dimeric acterised in the solid state by powder X-ray diffraction, N2 adsorption analysis, MAS NMR (13C, 29Si) and FTIR spectroscopy. The derivatised MCMs perform differently as catalysts in the liquid-phase oxidation of various olefins and alcohols with tert-butyl hydroperoxide. The highest alkene epoxidation activity was recorded for the catalysts with low metal loading, whereas the material containing oxo-bridged dimers had the highest activity for oxidation of alcohols. The recyclability of all the catalysts was tested: the catalytic activity of the derivatised materials tended to stabilize with ageing.
Synthesis and catalytic activity of organic-inorganic hybrid catalysts coordinated with cobalt(II) ions for aerobic epoxidation of styrene
Wei,Lu,Ma,Peng,Jiang,Zhou,Xia
, p. 48 - 52 (2015)
New organic-inorganic hybrid materials (HM) containing 3-mercaptopropyl groups (-(CH2)3-SH) have been synthesized through a dry gel conversion (DGC) route. The complex catalyst Co-HM was prepared through a simple coordination of -SH with cobalt(II) ions, which was firstly applied in the aerobic epoxidation of alkenes to obtain good results. Co-HM-50 exhibited the highest activity for the epoxidation of styrene with air to achieve 95.8 mol% of conversion with the epoxide selectivity of 89.2%. Recycling and control tests showed high durability and heterogeneity of Co-HM-50 as a heterogeneous catalyst.
Synthesis of a reusable polymer anchored cobalt(II) complex for the aerobic oxidation of alkyl aromatics and unsaturated organic compounds
Islam, Sk Manirul,Ghosh, Kajari,Molla, Rostam Ali,Roy, Anupam Singha,Salam, Noor,Iqubal, Md Asif
, p. 61 - 69 (2014)
Polymer anchored cobalt(II) catalyst was synthesized and characterized. The solid catalyst was characterized by fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The catalytic activity of the complex was investigated for the oxidative functionalization of alkyl aromatics to benzylic ketones using O2 (1 atm) with 1 mmol H2O2. The oxidation of organic compounds with carbon-carbon double bond with molecular oxygen under atmospheric pressure in the presence of this catalyst has also been studied. Oxidation of alkenes, cycloalkenes and terpenes gave corresponding epoxy derivatives. The developed catalyst can be facilely recovered and reused six times without significant decrease in its activity and selectivity.
Co2 +-exchanged SAPO-5 and SAPO-34 as efficient heterogeneous catalysts for aerobic epoxidation of alkenes
Tang,Lu,Zhou,Tian,Niu,Zhang,Chen,Xia
, p. 42 - 47 (2013)
Co-SAPO-5 and Co-SAPO-34 were prepared by a simple ion-exchange route and firstly applied in the aerobic epoxidation of alkenes. Both catalysts exhibited high activities in the epoxidation of alkenes with air to achieve 92.0-91.9 mol% conversion with the epoxide selectivity of 89.5-90.5% for styrene, 71.6-80.0 mol% conversion with 94.8-95.0% selectivity for α-pinene, and 95.3-96.8 mol% conversion with 75.2-73.6% selectivity for α-methyl styrene. Recycling studies and control experiments showed the recyclability and stability of Co-SAPO-5 and Co-SAPO-34 as heterogeneous catalysts.
Epoxidation of olefins by molecular oxygen using perfluorocarbons as reaction media
Pozzi, Gianluca,Montanari, Fernando,Rispens, Minze T.
, p. 447 - 452 (1997)
Epoxidation of olefins by dioxygen in combination with aldehyde as reducing agent can be carried out at room temperature, in the absence of metal catalysts, using perfluorocarbons as inert reaction media. These non-toxic, non ozone-depleting fluids are good alternatives to the chlorinated solvents normally used.
Chemoenzymatic epoxidation of alkenes by dimethyl carbonate and hydrogen peroxide
Rusch Gen Klaas, Mark,Warwel, Siegfried
, p. 1025 - 1026 (1999)
(matrix presented) Monoperoxy carbonic acid methyl ester can be generated under neutral conditions by lipase-catalyzed perhydrolysis of dimethyl carbonate with hydrogen peroxide. It can be used in situ for the selective and efficient epoxidation of olefins; the unstable coproduct carbonic acid monomethylester decomposes to carbon dioxide and methanol. Thus, an "acid-free" Prileshajev epoxidation is realized, which is especially useful for the epoxidation of acid-sensitive substrates such as β-pinene.
Hierarchical PS/PANI nanostructure supported Cu(ii) complexes: Facile synthesis and study of catalytic applications in aerobic oxidation
Yu, Jie,Luan, Yi,Qi, Yue,Hou, Junying,Dong, Wenjun,Yang, Mu,Wang, Ge
, p. 55028 - 55035 (2014)
Hierarchical heterogeneous copper catalysts were prepared by immobilization of a homogeneous copper(ii) complex on the surface of polystyrene/polyaniline (PS/PANI) microspheres with oriented PANI nanofibers. EDX element maps and XPS spectra indicated that Cu2+ ions strongly coordinated with PANI imine. PS/PANI@Cu(OSO2CF3)2 exhibited excellent catalytic activity for selective aerobic oxidation of alcohols and highly efficient aerobic epoxidation of alkenes under mild conditions. The supported copper(ii) catalyst maintained high levels of conversion and selectivity in these reactions after six cycles and showed good stability. This journal is
Single bilayered organic nanotubes: Anchors for production of a reusable catalyst with nickel ions
Chattopadhyay, Tanmay,Kogiso, Masaki,Aoyagi, Masaru,Yui, Hiroharu,Asakawa, Masumi,Shimizu, Toshimi
, p. 1138 - 1140 (2011)
Organic nanotubes self-assembled from lipid compounds facilitate the synthesis of a new nano-catalyst with nickel ions. The nickel ions were fixed on the surface of the organic nanotubes through coordination. The nanotubes catalyzed oxidation of a wide range of organic compounds with hydrogen peroxide without organic solvent, and are reusable in at least five cycles without loss of activity.
