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Catalyst Performance (catalyst + performance)
Selected AbstractsNew Iron(II) Complexes for Atom-Transfer Radical Polymerization: The Ligand Design for Triazacyclononane Results in High Reactivity and Catalyst PerformanceADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2009Mitsunobu Kawamura Abstract Mononuclear cordinatively unsaturated iron(II) complexes having a triazacyclononane ligand were developed as highly efficient and environmentally friendly catalysts for the atom-transfer radical polymerization (ATRP). These iron catalysts showed high performance in the well-controlled ATRP of styrene, methacrylates, and acrylates. The high reactivity of these catalysts led to well-controlled polymerization and block copolymerization even with lower catalyst concentrations. [source] Retaining Catalyst Performance at High Temperature: The Use of a Tetraphosphine Ligand in the Highly Regioselective Hydroformylation of Terminal OlefinsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2007Yongjun Yan Abstract A new tetraphosphine ligand has been developed and applied in the highly regioselective hydroformylation of terminal olefins. The ligand retains high performance at high temperature when compared with its bisphosphine analogue. [source] MCM-41 Bound Ruthenium Complex as Heterogeneous Catalyst for Hydrogenation I: Effect of Support, Ligand and Solvent on the Catalyst PerformanceCHINESE JOURNAL OF CHEMISTRY, Issue 7 2006Ying-Min Yu Abstract The functionalized MCM-41 mesoporous bound ruthenium complex was synthesized and characterized using elemental analysis, atomic absorption spectrophotometer, BET, XRD and FTIR. Hydrogenation of carbon dioxide to formic acid was investigated over these catalysts under supercritical CO2 condition. The effect of reactant gas partial pressure, supports, solvents and ligands on the synthesis of formic acid was studied. These factors could influence the catalyst activity, stability and reuse performance greatly and no byproduct was detected. These promising catalysts also offered the industrial advantages such as easy separation. [source] Efficiency analysis of a combined PEFC and bioethanol-solar-reforming system for individual housesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2010Shin'ya Obara Abstract In this research, the development of a bioethanol reforming system for fuel cells (FBSR: fuel cell with bioethanol steam reforming) using sunlight as a heat source was investigated. The system was investigated using the experimental result of catalyst performance, and numerical analysis. If ethanol purity is high, the production method of the bioethanol used for the proposal system will not be limited. The overall efficiency of the production of electricity and heat power of this system was determined by examining its thermal output characteristic. The FBSR was introduced into standard individual houses in Sapporo, Japan, for analysis. The amount of hydrogen production, the production-of-electricity characteristic, and the thermal output characteristic were examined using meteorological data on representative days in March and August. Compared with the representative day in March (28.0,MJ,day,1), the solar radiation of the representative day in August (37.0,MJ,day,1) is large. However, the amount of solar radiation fluctuation of the representative day in August in this analysis is large compared with the representative day in March. It depends for the overall efficiency of the system on the amount of solar radiation fluctuation rather than the amount of solar radiation. As a result, the overall efficiency of the system, defined as the rate of power and heat output compared with the amount of solar heat collected, was calculated to be 47.4 and 41.9% on the representative days in March and August, respectively. Copyright © 2009 John Wiley & Sons, Ltd. [source] Embedded Phases: A Way to Active and Stable CatalystsCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 1 2010Loredana De, Rogatis Dr. Abstract Industrial catalysts are typically made of nanosized metal particles, carried by a solid support. The extremely small size of the particles maximizes the surface area exposed to the reactant, leading to higher reactivity. Moreover, the higher the number of metal atoms in contact with the support, the better the catalyst performance. In addition, peculiar properties have been observed for some metal/metal oxide particles of critical sizes. However, thermal stability of these nanostructures is limited by their size; smaller the particle size, the lower the thermal stability. The ability to fabricate and control the structure of nanoparticles allows to influence the resulting properties and, ultimately, to design stable catalysts with the desired characteristics. Tuning particle sizes provides the possibility to modulate the catalytic activity. Unique and unexpected properties have been observed by confining/embedding metal nanoparticles in inorganic channels or cavities, which indeed offers new opportunities for the design of advanced catalytic sytems. Innovation in catalyst design is a powerful tool in realizing the goals of more green, efficient and sustainable industrial processes. The present Review focuses on the catalytic performance of noble metal- and non precious metal-based embedded catalysts with respect to traditional impregnated systems. Emphasis is dedicated to the improved thermal stability of these nanostructures compared to conventional systems. [source] Pore network model for catalytic dehydration of methanol at particle levelAICHE JOURNAL, Issue 2 2009Hossein Beigi Abstract ,-Alumina is used as a catalyst for converting methanol to dimethyl ether. The process takes place in a packed or fluidized bed reactor consisting of microporous particles with distributed pore sizes and interconnectivities. The efficiency of the process is, however, significantly affected by the pore space structure of the particles. All the previous attempts for modeling this phenomenon have used continuum formulation of the problem based on classical equations of mass transport and reaction, without any regards for the effect of pore space morphology. In this article, we study the catalyst's performance by developing a network model for the pore space, with distributed pore sizes and interconnectivities. The network model is used to study the effect of several parameters such as pore space morphology, concentration, and temperature on catalyst's effectiveness factor. The results will be used for reactor simulations. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source] Sodium Borohydride Hydrolysis as Hydrogen Generator: Issues, State of the Art and Applicability Upstream from a Fuel CellFUEL CELLS, Issue 3 2010U. B. Demirci Abstract Today there is a consensus regarding the potential of NaBH4 as a good candidate for hydrogen storage and release via hydrolysis reaction, especially for mobile, portable and niche applications. However as gone through in the present paper two main issues, which are the most investigated throughout the open literature, still avoid NaBH4 to be competitive. The first one is water handling. The second one is the catalytic material used to accelerate the hydrolysis reaction. Both issues are objects of great attentions as it can be noticed throughout the open literature. This review presents and discusses the various strategies which were considered until now by many studies to manage water and to improve catalysts performances (reactivity and durability). Published studies show real improvements and much more efforts might lead to significant overhangs. Nevertheless, the results show that we are still far from envisaging short-term commercialisation. [source] | ||||||||||