نتایج جستجو برای: based catalyst
تعداد نتایج: 2970333 فیلتر نتایج به سال:
In previous work by the authors, aspects of the surface chemistry connected with methyl chloride synthesis over an η-alumina catalyst have been examined. This communication considers a role for Group 1 metal salts to modify the catalytic performance of the well characterised η-alumina catalyst. Firstly, based on a previously postulated mechanism for the reaction of methanol on η-alumina, a mech...
A Pd-based heterogeneous catalyst (Pd(II)-MCM-41) derived from post-synthesis modification of mesoporous silica, MCM-41, has been successfully employed in catalytic Stille and Sonogashira cross-coupling reactions. The catalyst affords good yields in all cross-coupling reactions. Notably, the catalyst is capable of activating less reactive chlorobenzene with moderate yield in both the coupling r...
Aqueous NMR Signal Enhancement by Reversible Exchange in a Single Step Using Water-Soluble Catalysts
Two synthetic strategies are investigated for the preparation of water-soluble iridium-based catalysts for NMR signal amplification by reversible exchange (SABRE). In one approach, PEGylation of a variant N-heterocyclic carbene provided a novel catalyst with excellent water solubility. However, while SABRE-active in ethanol solutions, the catalyst lost activity in >50% water. In a second approa...
Heterogeneous catalysts are promising for the transesterification reaction of vegetable oils to produce biodiesel and have been studied intensively over the last decade. Unlike the homogeneous catalysts, heterogeneous catalysts can be easily separated from reaction mixture and reused for many times. They are environmentally benign and could be easily operated in continuous processes. This revie...
In this study, we examined a scale-up to production of nickel perovskite catalyst, used in the conversion of natural gas to synthesis gas, using the sol-gel method in the laboratory and a bench-scale reactor. The required volume of solvent and catalyst activity in the methane-reforming reaction was determined from the optimum catalyst production conditions at the laboratory scale. This informat...
An expanded family of ruthenium-based metathesis catalysts bearing cyclic alkyl amino carbene (CAAC) ligands was prepared. These catalysts exhibited exceptional activity in the ethenolysis of the seed-oil derivative methyl oleate. In many cases, catalyst turnover numbers (TONs) of more than 100,000 were achieved, at a catalyst loading of only 3 ppm. Remarkably, the most active catalyst system w...
the aim of this paper is to study the kinetic study carbonylation of methanol using of the homogeneous rhodium catalyst and ch3i as the promoter in acid media based on monsanto process. the reaction was carried out in liquid media in the constant pressures 20,28 and 40 atm. and temperatures 170 to185oc, espect to the initial reactant concentrations and co pressure. it was identified that the...
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