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911.
Shandong Yuan Sharifah Bee Derouane-Abd Hamid Yongxue Li Pinliang Ying Qin Xin Eric G Derouane Can Li 《Journal of molecular catalysis. A, Chemical》2002,180(1-2):245-258
The conversion of n-C4H10 was undertaken on MoO3/HZSM-5 catalyst at 773–973 K and the phases of molybdenum species were detected by XRD. The XRD results show that bulk MoO3 on HZSM-5 can be readily reduced by n-C4H10 to MoO2 at 773 K and MoO2 can be gradually carburized to molybdenum carbide above 813 K. The molybdenum carbide formed from the carburization of MoO2 with n-C4H10 below 893 K is -MoC1−x with fcc-structure, while hcp-molybdenum carbide formed above 933 K. During the evolution of MoO3 to MoO2 (>773 K) or the carburization of MoO2 to molybdenum carbide (>813 K), deep oxidation, cracking and coke deposition are serious, in particular at higher reaction temperatures, these lead to the poor selectivity to aromatics. Aromatization of n-C4H10 can proceed catalytically on both Mo2C/HZSM-5 and MoO2/HZSM-5, the distribution of the products for the two catalysts is similar below 813 K, but the activity for Mo2C/HZSM-5 is much higher than that for MoO2/HZSM-5. 相似文献
912.
C. Bibaut‐Renauld D. Burget J. P. Fouassier C. G. Varelas J. Thomatos G. Tsagaropoulos L. O. Ryrfors O. J. Karlsson 《Journal of polymer science. Part A, Polymer chemistry》2002,40(18):3171-3181
The efficiency of several α‐diketones as visible light photoinitiators for the crosslinking of waterborne latex dispersions in the presence of acrylic monomers was evaluated. Among the eight α‐diketones studied, camphorquinone allows the fastest curing speed, and the curing of the acrylic waterborne coating is not affected by the presence of oxygen. The properties of the sunlight‐cured volatile organic compound (VOC)‐free pigmented paints prepared from the waterborne latex are as good or better than the equivalent conventional paint containing VOCs. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3171–3181, 2002 相似文献
913.
914.
915.
Eu(Ⅲ)、Tb(Ⅲ)、Ho(Ⅲ)、Tm(Ⅲ)和Lu(Ⅲ)与N,N′-二(邻羟基亚甲基)乙二胺配合物的研究 总被引:1,自引:0,他引:1
Dutt曾合成稀土离子与N,N′-二(邻羟基亚甲基)乙二胺的稀土双希夫碱配合物。但未见报道Eu(Ⅲ),Tb(Ⅲ),Ho(Ⅲ),Tm(Ⅲ),Lu(Ⅲ)与双希夫碱N,N′-二(邻羟基亚甲基)乙二胺的配合物。本工作合成了这5种双希夫碱配合物。 所用稀土氧化物纯度大于99.9%(上海跃龙化工厂)。水杨醛(CP,用前经减压蒸馏提纯)。稀土硝酸盐Ln(NO_3)_3·xH_2_由稀土氧化物与硝酸反应制得。其余试剂均为分析纯。 仪器为Perkin-Elmer 240-C元素分析仪;Nicolet-5DX型红外光谱仪,KBr压片;岛津UV- 相似文献
916.
Hans‐Peter Kormann Günter Schmid Katrin Pelzer K. Philippot Bruno Chaudret 《无机化学与普通化学杂志》2004,630(12):1913-1918
Nanoporous alumina membranes, loaded with palladium and ruthenium nanoparticles of various size, were used for gas phase hydrogenation of 1, 3‐butadiene and for oxidation of carbon monoxide, respectively. Those membranes contain 109 ‐ 1011 pores per cm2, all running perpendicular to the surface. Membrane discs of 20 mm in diameter and only 60 μm thick, incorporated in a reactor in which the reactants can be pumped in a closed circuit through the pores, turned out to very actively catalyze hydrogenation of butadiene (Pd) and oxidation of CO (Ru). The activity of the Pd catalysts depends characteristically on the particles size, the gas flow, and of the educts ratio. As could be expected, larger particles are less active than smaller ones, whereas increasing gas flows in case of hydrogenation accelerates the reactions. Excessive hydrogen reduces selectivity with respect to the various butenes, but favours formation of butane. 相似文献
917.
A. Subbiah Pandi V. Rajakannan D. Velmurugan Masood Parvez Moon‐Jib Kim A. Senthilvelan S. Narasinga Rao 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o164-o167
N‐(2‐Chlorobenzyl)‐1,2,3,4‐tetrahydroisoquinoline‐1,3‐dione, C16H12ClNO2, crystallizes in P21/n with three crystallographically independent molecules in the asymmetric unit, which differ slightly in conformation, N‐(2‐bromo‐4‐methylphenyl)‐1,2,3,4‐tetrahydroisoquinoline‐1,3‐dione, C16H12BrNO2, crystallizes in P21/n with one molecule in the asymmetric unit andN‐(2,3‐dichlorophenyl)‐1,2,3,4‐tetrahydroisoquinoline‐1,3‐dione, C15H9Cl2NO2, crystallizes in P21/c with one molecule in the asymmetric unit. In all three structures, the heterocyclic rings adopt approximately planar conformations. The pyridine rings are orthogonal to the substituted phenyl rings. In all three structures, the crystal packing is stabilized by intermolecular C—H?O hydrogen bonds. 相似文献
918.
Zhaoyang Cheng Shipei Xing Jun Guo Biao Cheng Lan‐Fang Hu Xing‐Hong Zhang Zhan Lu 《中国化学》2019,37(5):421-421
The cover picture shows that sequential 1,1‐dihydrosilylation of terminal aliphatic alkynes with primary silanes enabled by one earth‐abundant cobalt catalyst has been developed. This protocol is operationally simple using readily available aliphatic alkynes, including simple acetylene and complex drug derivative, for efficient access to valuable gem‐bis(dihydrosilyl)alkanes in highly regioselective and atom‐economic manners. Corresponding asymmetric transformations are achieved with excellent enantioselectivities. More details are discussed in the article by Lu et al. on page 457–461.
919.
Highly dispersed α-Fe_2O_3/NaY,NiO/NaY,and CuO/NaY catalyst systems were pre-pared by impregnation method.Dispersion thresholds of the transition metal oxides on NaY" zeolitewere determined by XRD phase analysis.The dispersion capacities of the transition metal oxides on NaYzeolite are much lower than that estimated on the basis of a closed packed monolayer in the micropores.The catalytic activity and selectivity of the highly dispersed oxide catalyst systems for ethylben-zene and cyclohexane dehydrogenation reactions were reported. 相似文献
920.