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231.
Three photocatalytic oxidation (PCO) systems: C7H16-O2, SO2-O2 and C7H16-SO2-O2 were carried out with the aid of UV-illuminated TiO2 nanoparticles at room temperature in a batch reactor. In C7H16-O2-TiO2 system, no catalyst deactivation was observed, while for SO2-O2-TiO2 and C7H16-SO2-O2-TiO2 systems, the photocatalytic activity of used TiO2 powder showed decreasing and eventually no activity after used consecutively. The reaction products such as sulfur trioxide or sulfuric acid adsorbed onto the surface of TiO2 catalyst were poisoning species. Photocatalytic activity of the deactivated TiO2 powder could be regenerated by sonicating treatment with water and methanol for the two systems, respectively. 相似文献
232.
L. C. Du S. C. Tiong Q. Zhu Allan S. Hay 《Journal of polymer science. Part A, Polymer chemistry》2002,40(21):3579-3591
Zinc glutarates were synthesized from zinc oxides with varying purities via different stirring routes. The particle size and structure of these zinc glutarates were determined by wide‐angle X‐ray diffraction, transmission electron microscopy, and the laser particle size analyzer technique. The results demonstrated that the crystallinity and crystalline perfectness of zinc glutarate are the crucial factors that affect the catalytic activity for the copolymerization of carbon dioxide (CO2) and propylene oxide (PO). Additionally, the catalyst with a small particle size dramatically increased the yield of the copolymerization between CO2 and PO. High‐molecular‐weight and regular molecular structure poly(propylene carbonate)s (PPC)s were obtained from CO2 and PO with the synthesized zinc glutarates. Very high catalytic activity of 160.4 g polymer/g catalyst was afforded. The NMR technique revealed that the PPC copolymer exhibits an exact alternating copolymer structure. The relationships between the crystallinity and the particle size of catalyst with the catalytic activity are correlated and discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3579–3591, 2002 相似文献
233.
Yajing Yin Ping Wu Yafen Lü Pan Du Yanmao Shi Chenxin Cai 《Journal of Solid State Electrochemistry》2007,11(3):390-397
A single-walled carbon nanotube (SWNT)-modified electrode was fabricated and characterized by SEM and ac impedance techniques.
The direct electrochemistry of cytochrome c (Cyt c), which was adsorbed on the surface of the SWNT, was studied by cyclic voltammetry. The results from cyclic voltammetry and
infrared spectroscopy indicated that Cyt c remained in its original structure and did not undergo structural change after its immobilization on the SWNT. Further results
demonstrated that the SWNT had promotional effects on the direct electron transfer of Cyt c and also indicated that the immobilized Cyt c retained its electrocatalytic activity to the reduction of H2O2. This modified electrode might be used in development of new biosensors and the biofuel cells. 相似文献
234.
An approach was reported to synthesize silica hybridized ruthenium bipyridyl complex through amidation reaction by covalent attachment of bis(bipyridyl)-4,4'-dicarboxy-2,2'-bipyridyl-ruthenium to (3-aminopropyl)-triethoxysilane. The hybrid complex then was gelatinized through acid catalytic hydrolysis method and a sol-gel modified indium tin oxide electrode was prepared via spin coating technique. As prepared indium tin oxide electrode possesses good stability therein with excellent electrochemiluminescence behavior. 相似文献
235.
Capillary zone electrophoresis was used for characterising nine samples of natural organic matter (NOM) using phosphate buffer (25 mM, pH 7) and various modifiers; methanol (50 mM), acetonitrile (10%,v/v), dimethyl sulfoxide (5%,v/v), and urea (5 M). Principal component analysis (PCA) was used to examine whether the electrophoretic profiles can be utilised as fingerprints for tracing the NOM samples to their source and/or type of location. It was found that all modifiers except methanol affect the electropherograms. Furthermore, it was found that the PCA analysis carried out on the electrophoretic profiles recorded in buffer solution modified by urea gave the best results for fingerprinting. The distribution of the fingerprints suggests a model for the humic substances in which all samples can be regarded as mixtures between two endmembers: autochtonous and allocthoneous NOM. 相似文献
236.
Summary The equilibrium mechanical behaviour of weak diepoxide-monoepoxide-diamine networks, prepared with an excess of diamine and measured in the rubbery state, was compared with theoretical predictions obtained by using the theory of branching processes. The experimental equilibrium moduli fit well the shape of theoretical curves over a broad range of crosslinking density regardless of whether the contribution by trapped entanglements is considered or not. The data fit equally well the theoretical dependence for the front factor A = 1 without entanglement contribution and forA = (f
e
- 2)/f
e
, (f
e
is the average effective functionality of a junction) with an entanglement contribution based on the contact probability between any two units within elastically active network chains (Langley).Dedicated to Prof. Dr.G. Rehage on the occasion of his 60th birthday.With 5 figures 相似文献
237.
Xie Yongshu Ni Jia Liu Xueting Liu Qingliang Xu Xiaolong Du Chenxia Zhu Yu 《Transition Metal Chemistry》2003,28(3):367-370
Novel 1:2 and 1:1 (M:L) copper(II) complexes have been prepared from the tridentate ligand 2-(1-methyl-2-aza-5-oxapentyl)phenol (H2L1). The crystal structure of [Cu(HL1)2] (1) exhibits a noncentrosymmetric square-planar geometry with a slightly tetrahedral distortion. The CuII atom is coordinated by two amino N and two phenoxo O atoms of two (HL1)– ligands. The phenoxo and the alkoxy groups are involved in two strong intramolecular hydrogen bonds. The coordination moieties are further connected to a 1D linear structure by the action of intermolecular hydrogen bonds between the alkoxyl and the amino groups. The importance of steric hindrance introduced by the methyl group in the molecular structure and the packing of the complex molecules has been demonstrated. The e.p.r. parameters of (1) have been obtained: g
= 2.231, g
= 2.005, g
iso = 2.080, A
= 185.0 G, A
iso = 86.5 G, A
= (3A
iso – A
)/2 = 37.3 G. These results confirm a distorted square planar stereochemistry with a (
)1 ground state. 相似文献
238.
HongBingJI DuGuiHE JunSONG YuQIAN 《中国化学快报》2004,15(10):1241-1244
Clean liquid oxidation of aldehydes can be accomplished using solid catalyst in the presence of molecular oxygen at room temperature, which is a valuable alternative to traditional counterparts. 相似文献
239.
Josep Castells Elisabet Duñach Fernando Geijo Francisco López-Calahorra Margarita Prats Olga Sanahuja Laura Villanova 《Tetrahedron letters》1980,21(23):2291-2294
Triethylamine catalyzed Michael additions of benzoins to chalcone can prevail over the expected Michael-Stetter additions when certain thiazolium ion conjugate bases - prepared from the pertinent thiazolium salts and triethylamine- are used as catalysts. 相似文献
240.
A unique cyano-bridged copper(II)-copper(I) mixed-valence polymer, {[Cu(3)(CN)(4)(H(2)O)(3)](H(2)O)(2)}(n) (1), has been prepared and structurally determined by X-ray diffraction. The cyanide anions with (mu(2),eta(2)) and (mu(3),eta(2)) bridging modes connect the copper centers into a complicated zeolite-like 3-D network. Of further interest, coordinated and lattice water molecules in this structure form 1-D hydrogen-bonded water tapes consisting of linked cyclic pentamer clusters. 相似文献