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141.
K. Brodersen F. Weigel H. Pohl G. Denk K. Cruse Sigrid Hüttig und H. Kurtenacker 《Fresenius' Journal of Analytical Chemistry》1956,149(5):390-395
Ohne Zusammenfassung 相似文献
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Melanie Schnell Max Mühlhuser George E. Froudakis Sigrid D. Peyerimhoff 《Chemical physics letters》2001,340(5-6):559-564
Large-scale ab initio coupled cluster and multi-reference configuration interaction calculations (MRD-CI) are carried out to determine the equilibrium geometry and the vertical electronic spectrum of linear C5+. Contrary to prior theoretical estimates we find three low-lying states within an energy range of 0.3 eV: 2Σu+, 2Σg+ and 2Πg and a symmetric arrangement of nuclei. Transitions from 2Σu+ to these low-lying states are dipole-allowed; sizeable oscillator strengths are computed for the 2Π+g←X2Σu+ transition at 2.62 eV and the 2Σg←X2Σu+ transition at 3.36 eV and should give a guide to spectroscopic identification of linear C5+. 相似文献
145.
Propyne iminium triflates R1C(N+R3R4)CCR2 CF3SO readily react with Ph3PNPh to form 1:1 adducts which formally result from a metathetical addition of the phosphorane imine across the triple bond of the alkyne. These adducts are best described as enamino‐phosphonium salts or iminio‐substituted phosphorus ylides. The configuration of these salts has been determined from NMR data and an X‐ray crystal structure analysis of salt 3h . The base‐induced elimination of the PPh3 substituent from enamino‐phosphonium salt 3a was studied. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:437–446, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20131 相似文献
146.
Biologic conversion of inexpensive and abundant sources of cellulosic biomass offers a low-cost route to production of fuels
and commodity chemicals that can provide unparalleled environmental, economic, and strategic benefits. However, low-cost,
high-yiel technologies are needed to recover sugars from the hemicellulose fraction of biomass and to prepare the remaining
cellulose fraction for subsequent hydrolysis. Uncatalyzed hemicellulose hydrolysis in flow-through systems offers a number
of important advantages for removal of hemicellulose sugars, and it is believed that oligomers could play an important role
in explaining why the performance of flow-through systems differs from uncatalyzed steam explosion approaches. Thus, an effort
is under way to study oligomer formation kinetics, and a small batch reactor is being applied to capture these important intermediates
in a closed system that facilitates material balance closure for varying reaction conditions. In this article, heat transfer
for batch tubes is analyzed to derive temperature profiles for different tube diameters and assess the impact on xylan conversion.
It was found that the tube diameter must be <0.5 in, for xylan hydrolysis to follow the kinetics expected for a uniform temperature
system at typical operating conditions. 相似文献
147.
Dietmar Rakowitz Gottfried Heinisch Peter Lukavsky Sigrid Kiendler Cornelia Trenkwalder Daniela Barlocco Giulio Rastelli Luca Costantino 《Journal of heterocyclic chemistry》2000,37(5):1089-1096
In the course of our research aimed at the discovery of new compounds acting as aldose reductase inhibitors, we tested a series of some (E)‐ and (Z)‐ω‐[[(aryldiazinylmethylene)amino]oxy]alkanoic acids, which were found to have moderate in vitro inhibitory activity. On this basis we have now prepared several new derivatives modified both at the length of the chain and at its terminal carboxylic group, together with compounds carrying various substituents at the phenyl ring. This paper describes their synthesis and biological properties. 相似文献
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Mennickent Sigrid Mario Vega M. Mario Vega H. De Diego Marta Fierro Ricardo 《平面色谱法杂志一现代薄层色谱法》2012,25(1):54-59
JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatography (HPTLC) method for the quantification of propranolol in human serum is developed and... 相似文献