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排序方式: 共有184条查询结果,搜索用时 109 毫秒
1.
Yue Liu Mingxin Lv Lu Li Hailong Yu Qiong Wu Jinhui Pang Yuxiang Liu Congxia Xie Shitao Yu Shiwei Liu 《应用有机金属化学》2019,33(4)
An amino‐functionalized silica‐coated Fe3O4 nanocomposite (Fe3O4@SiO2/APTS) was synthesized. The Fe3O4@SiO2 microspheres possessed a well‐defined core–shell structure, uniform sizes and high magnetization. An immobilized ruthenium nanoparticle catalyst (Fe3O4@SiO2/APTS/Ru) was obtained after coordination and reduction of Ru3+ on the Fe3O4@SiO2/APTS nanocomposite. The Ru nanoparticles were not only ultra‐small with nearly monodisperse sizes but also had strong affinity with the surface of Fe3O4@SiO2/APTS. The obtained catalyst exhibited excellent catalytic performance for the hydrogenation of a variety of aromatic nitro compounds, even at room temperature. Moreover, Fe3O4@SiO2/APTS/Ru was easily recovered using a magnetic field and directly reused for at least five cycles without significant loss of its activity. 相似文献
2.
Mingxin Liu Chao‐Jun Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(36):10964-10968
The first example of homogeneous copper‐catalyzed aerobic oxidation of aldehydes is reported. This method utilizes atmospheric oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes. Chromatography is generally not necessary for product purification. 相似文献
3.
Jinjuan Xue Chengjuan Huang Yuqing Zong Jiandong Gu Mingxin Wang Shuaishuai Ma 《应用有机金属化学》2019,33(11)
Fe (III)‐grafted Bi2MoO6 nanoplates (Fe (III)/BMO) with varying small quantity of Fe (III) clusters modification were fabricated through a simple hydrothermal and impregnation process. The characterization results indicate that the modification of Fe (III) clusters on the surface of Bi2MoO6 nanoplates with intimate interfacial contact is beneficial to the expansion of visible light absorption range and the separation of photoinduced carriers during the interface charge transfer process. The photocatalytic properties of the samples were studied by degradation of tetracycline (TC) and selective aerobic oxidation of biomass‐derived chemical 5‐hydroxymethylfuraldehyde (HMF) under visible light. The 1.5 wt% Fe (III) clusters‐grafted Bi2MoO6 nanoplates exhibited optimum photocatalytic activity, which is the TC degradation kinetic rate constant is 5.3 times higher than that of bare BMO, and the highest HMF conversion of 32.62% can be obtained with a selectivity of 95.30%. Furthermore, a possible visible light photocatalysis mechanism over Fe (III)/BMO sample has been proposed. This study may supply some insight for the development of visible‐light‐driven Bi2MoO6‐based photocatalysts applicable to both environmental remediation and biomass‐derived chemical transformation. 相似文献
4.
Organosamarium reagent reacts with disulfides to afford allyl sulfides in THF. 相似文献
5.
Wenshuai Chen Haipeng Yu Yixing Liu Yunfei Hai Mingxin Zhang Peng Chen 《Cellulose (London, England)》2011,18(2):433-442
Cellulose nanofibers (CNFs) were isolated from four kinds of plant cellulose fibers by a chemical-ultrasonic treatment. The
chemical composition, morphology, crystalline behavior, and thermal properties of the nanofibers and their intermediate products
were characterized and compared. The CNFs extracted from wood, bamboo, and wheat straw fibers had uniform diameters of 10–40 nm, whereas the flax fibers were not uniformly nanofibrillated because of their initially high cellulose content. The chemical
composition of each kind of nanofibers was mainly cellulose because hemicelluloses and lignin were significantly removed during
chemical process. The crystallinity of the nanofibers increased as the chemical treatments were applied. The degradation temperature
of each kind of nanofiber reached beyond 330 °C. Based on the properties of the CNFs, we expect that they will be suitable
for use in green nanocomposites, filtration media and optically transparent films. 相似文献
6.
The application of chitosan (CS) in new materials is a hot research topic. In this paper, CS was used alone as flame retardant to prepare thermoplastic polyurethane elastomer (TPU) composites. Then, the flame retardancy and thermal decomposition behavior of TPU/CS composites were intensively investigated using cone calorimeter test (CCT), scanning electron microscope (SEM), microscale combustion colorimeter (MCC) test, thermogravimetric analysis/infrared spectrometry (TG‐IR), and gas chromatography‐mass spectrometry (GC‐MS). The results showed that CS can reduce the fire risk of TPU; 2.0‐wt% CS could make the peak value of heat release rate (pHRR) decreased to 457.2 kW/m2, reduced by 65.9% compared with TPU. And the peak value of smoke production rate (pSPR) and total smoke release (TSR) of the same sample was decreased by 79.4% and 54.2%, respectively. The TG‐IR and GC‐MS results confirmed that CS could promote TPU decomposition in advance, reacting with the decomposition products of TPU. Therefore, the production of combustible gas was reduced. The GC‐MS results showed that the production of isocyanates and ethers was reduced with the addition of CS. The digital photographs of SEM for the samples after CCT were shown that the char residue layer of the sample containing 2.0‐wt% CS was fibrous in shape. It could be speculated that the thermal decomposition products from TPU could react with CS at low temperature, which reduced the production of flammable gases. So CS had a good prospect in reducing the fire hazard for TPU. 相似文献
7.
The electronic excitations and the static first hyperpolarizability of three typical transition metal (TM) aromatic carbonyl complexes, two tungsten pentacarbonyl derivatives (W(CO)5L, L = Py and PyCHO) and one chromium tricarbonyl arene derivative (Cr(CO)3Bz, Bz = benzene), have been theoretically studied by a variety of density functional methods. The assessments reveal that most of the conventional DFT methods including local density approximation, generalized gradient approximation (GGA), and the various kinds of hybrid exchange‐correlation (xc) methods present the first hyperpolarizabilities of these TM‐containing molecules with large deviations from the experiments. A one‐parameter hybrid xc functional is introduced by using the Perdew‐Wang 1991 gradient‐corrected correlation functional (PW91) and the Barone's‐modified PW91 exchange functional (mPW). The ratio between the exact and the density functional exchange is determined to be 0.40 by the adiabatic connection method. The application of the new hybrid functional to the three organometallic carbonyl molecules results in the satisfactory agreement between the calculated first hyperpolarizabilities and the experimental ones. The second‐order nonlinear optical properties of the three organometallic complexes are addressed to the metal‐to‐ligand charge transfers, and the extended π‐delocalization ligands benefit the enhancement of the first hyperpolarizability. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009 相似文献
8.
9.
Xiaolong Zheng Mingzhu Liu Mingxin He Prof. David J. Pine Prof. Marcus Weck 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(20):5599-5603
A facile method to synthesize shape-shifting patchy particles on the colloidal scale is described. The design is based on the solvent-induced shifting of the patch shape between concave and convex features. The initial concave patchy particles were synthesized in a water suspension by a swelling-induced buckling process. Upon exposure to different solvents, the patches were tuned reversibly to be either concave or convex. These particles can be assembled into chained, branched, zigzag, and cyclic colloidal superstructures in a highly site-specific manner by surface–liquid capillary bridging. The biphasic nature of the particles also enables site-selective surface functionalization. 相似文献
10.
In this paper we investigate the global existence and energy decay rate for the solution of a coupled hyperbolic system. The semi-explicit energy decay rate is established by using piecewise multiplier techniques and weighted integral inequality. We extend the energy decay result in Alabau-Boussouira [F. Alabau-Boussouira, Convexity and weighted integral inequalities for energy decay rates of nonlinear dissipative hyperbolic systems, Appl. Math. Optim. 51 (2005) 61-105] for a single equation to the coupled hyperbolic system. 相似文献