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121.
Glycerol hydrogenolysis to propylene glycol 总被引:1,自引:0,他引:1
Adriana Marinoiu Gheorghe Ionita Costinela-Laura Gáspár Claudia Cobzaru Spiridon Oprea 《Reaction Kinetics and Catalysis Letters》2009,97(2):315-320
A nickel catalyst showed a considerable selectivity to propylene glycol (up to 98%) at 30% glycerol conversion, under moderate
hydrogenation conditions: 200 °C reaction temperature, 20–25 bar hydrogen pressure, 5 wt% catalyst and unprecedented low reaction
time of 8 h. 相似文献
122.
Saravanakumar S Oprea AI Kindermann MK Jones PG Heinicke J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(11):3143-3154
Two novel anellated N-heterocyclic carbenes (NHC), 1,3-dineopentylnaphtho[2,3-d]imidazol-2-ylidene, and 1,3-dineopentyl-2-ylido-imidazolo[4,5-b]pyridine were obtained by reduction of the respective thiones with potassium, the former also by deprotonation of the corresponding naphthimidazolium hexafluorophosphate by using excess KH in THF. The use of equimolar amounts of KH provided an unexpected formal addition product of this NHC with KOH. X-ray crystal structure analysis of the adduct provided evidence for a distorted tetrameric N-heterocyclic alkoxide, stabilized by two THF molecules. In C(6)D(6) the compound undergoes disproportionation. Transition-metal complexes [(NHC)AgCl], [(NHC)Rh(cod)Cl], and (E)-[(NHC)(2)PdCl(2)] of the novel naphthimidazol-2-ylidene were synthesized. X-ray crystal structures and (1)H and (13)C NMR spectroscopic data provided detailed structural information. Comparing characteristic data with those of nonanellated and differently anellated NHCs or their complexes provides information on the influence of the extended anellation. 相似文献
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124.
Adrian Carabineanu Adrian Dinu Iuliana Oprea 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1995,46(6):971-981
A boundary element method is developed in order to investigate the flow of viscous, incompressible, electrically conducting fluids in cylindrical ducts having arbitrary cross-sections. The numerical results obtained for the circular duct with insulating wall are very close to the results obtained by means of analytical formulas. 相似文献
125.
Based on isochronous tests the stress-strain curve for thermoplastic polyurethane elastomers (Moldotan D) is plotted and used for correcting the tensile creep data.By plotting the -logD(t) master curve the experimental data obtained can be extrapolated to longer periods. 相似文献
126.
127.
A series of interpenetrating polymer networks (IPNs), based on a polyurethane (PU) and polydimethylsiloxane, has been synthesized and characterized by means of DSC, TEM, TGA, 1H-NMR and IR spectroscopies, and other techniques. The homo-networks have been characterized by swelling in n-hexane and chloroform. The IPNs are obtained by combination of a PU based of the castor oil and 2,4-toluene diisocyanate (TDI) with different amounts of polydimethylsiloxane-α,ω-diol (PDMS). These materials have interesting individual physical properties, but some IPNs exhibited superior properties than either of the separate networks. For interesting results, it was used as compatibilizer the polydimethylsiloxane graft polyalkylene oxide. All the IPNs exhibited phase separation and maximum extent at the point of phase inversion. 相似文献
128.
Two disperse dyestuffs, though exhibiting similar behaviour upon TG-DTG-DTA, have different dyeing properties. Thermoanalytical investigations are not sufficient to predict dyeing characteristics and fastness.
Zusammenfassung Zwei Dispersionsfarbstoffe, die sich bei der TG-DTG-DTA ähnlich verhalten, zeigen unterschiedliche Färbeeigenschaften. Thermoanalytische Untersuchungen sind nicht ausreichend, um Färbeeigenschaften und die Farbechteheit vorherzusagen.
, , , . .相似文献
129.
Methods that rapidly evaluate molecular complexity and synthetic feasibility are becoming increasingly important for in silico chemistry. We propose a new metric based on relative atomic electronegativities and bond parameters that evaluate both synthetic and molecular complexity (SMCM) starting from chemical structures. Against molecular weight, SMCM has the lowest fraction of adjusted variance (R2=0.535) on a series of 261,048 diverse compounds, when compared to the complexity metric of Baron and Chanon (R2=0.777; J. Chem. Inf. Comput. Sci. 2001, 41, 269-272) and Rücker (R2=0.895 for log complexity values; J. Chem. Inf. Comput. Sci. 2004, 44, 378-386), respectively. These metrics are in general agreement when the metabolic synthesis of cholesterol from S-3-hydroxy-3-methyl-glutaryl coenzyme A is monitored, indicating that SMCM can be useful in discerning increases in complexity. Because the presence of substructure patterns can be directly incorporated into this scheme, SMCM is relatively straightforward and can be easily tailored to rapidly evaluate virtual (combinatorial) libraries and high throughput screening hits. 相似文献
130.
We prove that the strange duality conjecture of Beauville–Donagi–Tu holds for all curves. We establish first a more extended
level-rank duality, interesting in its own right, from which the standard level-rank duality follows by restriction. 相似文献