Supported transition metal catalyst

Abstract—Carbon nanotubules were produced in a large amount by catalytic decomposition of acetylene in the presence of various supported transition metal catalysts. The influence of different parameters such as the nature of the support, the size of active metal particles and the reaction conditions on the formation of nanotubules was studied. The process was optimized towards the production of nanotubules having the same diameters as the fullerene tubules obtained from the arc-discharge method. The separation of tubules from the substrate, their purification and opening were also investigated. 

Besides supported (transition) metal catalysts, structure sensitivity can also be observed with bare (oxidic) support materials, too. In 2003, Hinrichsen et al. [39] investigated methanol synthesis at 30 bar and 300 °C over differently prepared zinc oxides, namely by precipitation, coprecipitation with alumina, and thermolysis of zinc siloxide precursor. Particle sizes, as determined by N2 physisorpt-ion and XRD, varied from 261 nm for a commercial material to 7.0 nm for the thermolytically obtained material. Plotting the areal rates against BET surface areas (Figure 3) reveals enhanced activity for the low surface area zinc... 

W. M. H. Sachtler and Z. Zhang, Zeolite supported transition metal catalysts, Adv. Catal. 39, 129-220(1993). 

Vapor-Phase Carbonylation of Dimethyl Ether and Methyl Acetate with Supported Transition Metal Catalysts... 

There has been considerable work in the literature on the structure of very small particles and clusters. Interest in this field has been primarily due to Ino s (1966) early experimental studies of normally fee metals prepared by vapour condensation which showed that a sizable portion of the particles exhibited non-crystallographic structures. These non-crystallographic atomic clusters or polycrystalline nuclei have been observed to consist of pentagonal bi-pyramid or icosahedra form of twinned structures and are known as multiply twinned particles (MTPs). EM studies of supported transition metal catalyst systems have indicated that MTPs sinter faster in catalytic reactions leading to the loss of surface area and are not beneficial to catalysis (Gai 1992). We describe the structure and the role of MTPs in catalysis in the following sections. 

In addition to these supported transition-metal catalysts, some soluble transition-metal compounds exhibit considerable activity in polymerization without added aluminum alkyls.292 The most active compounds are a-organometallics of Ti and Zr with methyl, benzyl, and halogen ligands. jt-Allyl compounds of Ti, Zr, and Cr are also useful catalysts. 

The effect of quinoline and CCI4 on the activity of silica-supported transition metal catalysts in the hydrogenation of 1-hexene and cyclohexene was studied212. 

The product in eq 4.17 results from dynamic ligand exchange ("redistribution reaction") of DSBM and DNBM. MgCl in eq 4.16 may be the insoluble by-product from synthesis of di-n-butylmagnesium in eq 4.15. This makes it possible to produce DBM in a "one-pot" synthesis. Though DBM in eq 4.17 is shown as if the n-butyl to sec-butyl ratio were 1, in practice the ratio is about 1.5. This minimizes the amount of costly sec-butyllithium that is needed. DBM is used to produce supported transition metal catalysts (discussed in sections 4.3.2 and 4.3.3). 

Oxidation of organic compounds using Hydrogen peroxide and tert.- BHP catalysed by polymer supported transition metal catalysts ... 

Chemically anchored, supported transition metal catalysts have been used extensively for production of high-density, linear polyethylene and ethylene-a-olefin copolymers. These supported... 

The author s own interest in this area includes new functional polymers for solid phase synthesis [11-13], polymers with molecularly imprinted substrate selectivity [14], polymer-supported transition metal catalysts [15], novel polymers of potential interest for electrocatalysis [16], targeting of colloidal drug carriers [17, 18], molecular composites [19], and biocompatible surfaces [20]. These studies have led to, among other things, a uniquely versatile method of polymer synthesis based on the chemistry of activated acrylates, i.e. polymer synthesis via activated esters. Various aspects of polymers and copolymers of activated (meth)acrylates have also been investigated in this and several other laboratories. 

Metal clusters in zeolites an intriguing class of catalysts Zeolite-supported transition metal catalysts Stoichiometric and catalytic reactivity of organometallic fragments supported on inorganic oxides Silver clusters and chemistry in zeolites Structure and reactivity of surface species obtained by interaction of organometallic compounds with oxidic surfaces infra-red studies... 

Polymer supported transition metal catalysts Asymmetric hydroformylation or oxidation reactions d... 

Stability of Polymer-Supported Transition Metal Catalysts... 

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