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31.
负载型无铬超细铁基变换催化剂的制备和催化性能 总被引:11,自引:0,他引:11
以镁铝尖晶石为载体,以过渡金属氧化物为助剂,用吸附γ-Fe2O3胶体法制备了负载型无铬铁基变换催化剂.TEM,XRD,BET和活性测试结果表明,采用胶体负载法制备的变换催化剂,其活性组分Fe3O4以分立的超细微颗粒分布在镁铝尖晶石载体表面上,颗粒之间存在一定的间隔.过渡金属氧化物NiO或V2O5能够进入Fe3O4晶格形成固溶体,起到代替氧化铬的作用,提高催化活性.负载型催化剂FeNi/MgAl2O4(m(NiO)/m(Fe2O3)=3%)在汽/气比为1和空速为2000h-1的反应条件下,CO转化率在400和350℃时分别为95%和80%;在高空速和低汽/气比条件下也具有很好的催化性能.稳定性实验结果表明,该催化剂
具有良好的热稳定性和一定的抗硫能力.与非负载型催化剂相比,负载型催化剂具有更为优越的催化性能. 相似文献
32.
[H+]在0.01~0.70mol?L-1范围内,离子强度为1.00mol?L-1,[Fe(III)]>>[配体]、[H+]>>[配体]的条件下,研究了Fe(III)与2,3-二羟基苯磺酸钠(Tiron)的配位反应.发现当[H+]≤3.00×10-2mol?L-1时,[Fe(III)]2对反应速率有明显的贡献.求得了相关反应的动力学参数,从而揭示了FeOH2+和FeOH24+与Tiron配位的解离反应途径及FeOH32+的缔合反应机制,并提出了该配位反应的可能机理. 相似文献
33.
微乳液法合成LiFePO4 / C正极材料及其电化学性能 总被引:4,自引:0,他引:4
本文采用微乳液方法合成了纳米LiFePO4 / C正极材料。制备样品分别用XRD和SEM进行表征,充放电测试其电化学性能。600 ℃制备样品为单一物相,平均粒径90 nm,在室温2.0~4.0 V (vs Li) 放电电压范围和15 mA·g-1放电速率下,首次放电容量达到159 mAh·g-1。制备样品同样展现良好的循环性能。在15 mA·g-1速率下40次循环后,制备样品放电容量仍保持首次放电容量的98.9%。优异的电化学性能得益于样品颗粒的纳米尺寸、均匀分布以及表面碳层包覆提高了活性材料的电子电导率。 相似文献
34.
B. G. Bazarov R. F. Klevtsova A. D. Tsyrendorzhieva L. A. Glinaskaya Zh. G. Bazarova 《Journal of Structural Chemistry》2004,45(6):993-998
Physicochemical analysis (XRPA, DTA) was used to study phase equilibria in a ternary salt system Rb2MoO4-Fe2(MoO4)3-Hf(MoO4)2 in the subsolidus region. Ternary molybdates with compositions 5:1:3, 5:1:2, and 1:1:1 have been found and synthesized. Crystal and thermal characteristics have been determined. Single crystals of the ternary molybdate Rb5FeHf(MoO4)6 with a composition of 5:1:2 were grown. The crystal structure of the compound was solved using X-ray diffractometry (CAD-4 automatic diffractometer, MoK
α radiation, 1766 F(hkl), R = 0.0298). Hexagonal crystals with unit cell dimensions: a = b = 10.124(1) Å, c =15.135(3) Å, V = 1343.4(4) Å3, Z = 2, ρcalc = 4.008 g/cm3, space group P63. The mixed three-dimensional framework of the structure is formed from two sorts of MoO4 tetrahedra and Fe and Hf octahedra linked through their common O-vertices. Rubidium atoms of three varieties occupy the large voids of the framework.Original Russian Text Copyright © 2004 by B. G. Bazarov, R. F. Klevtsova, A. D. Tsyrendorzhieva, L. A. Glinaskaya, and Zh. G. Bazarova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1038–1043, November–December, 2004. 相似文献
35.
Fadila Balegroune Pierre Braunstein Laurent Douce Yves Dusausoy Daniel Grandjean Michael Knorr Martin Strampfer 《Journal of Cluster Science》1992,3(3):275-296
The reactions of K[Fe{Si(OMe)3}(CO)3(PY)][PY=Ph2PCH2C(O)Ph, Ph2PCH2C(O)[(-C5H4)FeCp] (Cp=5-C5H5), Ph2P(CH2)2CN] with CdCl2·2.5H2O, ZnX
2 (X=Cl, I) or InCl3 afforded Fe-Cd-Fe or Fe-M(-X)2
M-Fe (M=Cd, Zn, In;X=Cl, I) and Fe-InCl2 complexes. Some of them contain an unusual and labile -2-SiO alkoxysilyl bridge which may be associated with a bridging mode for the ketophosphine ligand (first such example structurally established), thus providing original results in bimetallic chemistry on the intramolecular coordination of oxygendonor functions ofchemically different hemilabile ligands firmly attached to a neighboring metal center. The structures of the trinuclear complex (3), of the chlorobenzene solvate of the tetranuclear complex (4a·C6H5Cl) and of [mer-(OC)3{(EtO)3Si} (4e) have been determined by X-ray diffraction. Crystals of 3 are orthorhombic, space groupPbcn, witha=19.010(4),b=11.766(5),c=26.998(7)Å, andZ=4. Crystals of4a·C6H5Cl are monoclinic, space groupC2/c witha=22.455(3),b=17.680(2),c=16.627(4)Å, =90.80(4)°, andZ=4. Crystals of4e are monoclinic, space groupC2/c witha=25.392(5),b=18.554(6),c=16.28(1)Å, =120.73(3)°, andZ=4. The structures were solved using direct methods and Fourier difference techniques and refined by blocked full-matrix least squares toR=0.035 (R
w
=0.049) for 2719 observed reflections, toR=0.042 (R
w
=0.056) for 3082 observed reflections, and toR=0.057 (R
w
=0.075) for 1850 observed reflections for3, 4a·C6H5Cl and4e, respectively. The Fe-Zn complexes (9a), (9b) and (9c) were prepared and characterized by spectroscopic methods.Part 21 in the Series: Complexes with Functional Phosphines. Part 20: P. Braunstein, S. Coco Cea, A. DeCian, and J. Fischer (1992).Inorg. Chem.
31, 4203. 相似文献
36.
煤炭液化复合铁系催化剂的研究 总被引:1,自引:0,他引:1
用微型高压釜,以杂酚油为溶剂,在反应温度400℃,氢初压6.08MPa,反应时间30分钟的条件下,研究了多种含铁矿物质、复合铁系催化剂对煤炭液化的催化效果。并用高压DTA技术进一步证实了复合铁系催化剂的良好液化加氢活性。 相似文献
37.
The dielectric and magnetic properties of carbonyl—iron (CI) and nickel zinc ferrite polymer composites were studied with respect to the ferrite particulate content and microwave frequency. From the experimental data and using empirical models that relate the composite dielectric and magnetic properties, the respective dielectric and magnetic properties of the neat fillers were estimated. The tensile properties of the particulate composites comprising CI were shown to follow qualitatively Mooney's equation for the elastic modulus. The tensile strength of an elastomeric polyurethane and PVC composites containing CI increased with particulate content, while the elongation to break decreased with filler content. SEM micrographs of tensile fracture surfaces indicated that somewhat better adhesion is obtained in the case of the polyurethane-based composites compared to the PVC ones. 相似文献
38.
报道了用H_2Fe(CO)_4制备trans-Fe(CO)_3(PR_3)_2的新的羰基取代反应。在 过量质子存在下,H_2Fe(CO)_4中的羰基被活化,中心铁原子对膦的亲核进攻更为 敏感。在这种条件下H_2Fe(CO)_4与膦反应时,首先失去氢生成Fe(CO)_4(PR_3), Fe(CO)_4-(PR_3)再与第二个膦反应可高产率的得到trans-Fe(CO)_3(PR_3)_2。用 PPh_3与Fe(CO)_4(PPh_3)在过量质子存在下反应生成trans-Fe(CO)_3(PR_3)_2,证 实了上述过程。 相似文献
39.
反向流动注射化学发光法测定痕量铁 总被引:10,自引:1,他引:10
基于邻菲别名林对高碘酸钾-碱性鲁米诺-铁体系发光强度的增敏作用建立了水体中总铁的反向流动性化学发光检测方法。该法线性范围在1×10^-4-10mg/L,检测限为3×10^-6mg/L,对于5×10^-3mg/L Fe测定9次的相对标准偏差为0.9%。此方法已用在水处理中总铁的监测。 相似文献
40.
Bassan A Blomberg MR Siegbahn PE Que L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(2):692-705
The reactivity of [HO-(tpa)Fe(V)=O] (TPA=tris(2-pyridylmethyl)amine), derived from O-O bond heterolysis of its [H(2)O-(tpa)Fe(III)-OOH] precursor, was explored by means of hybrid density functional theory. The mechanism for alkane hydroxylation by the high-valent iron-oxo species invoked as an intermediate in Fe(tpa)/H(2)O(2) catalysis was investigated. Hydroxylation of methane and propane by HO-Fe(V)=O was studied by following the rebound mechanism associated with the heme center of cytochrome P450, and it is demonstrated that this species is capable of stereospecific alkane hydroxylation. The mechanism proposed for alkane hydroxylation by HO-Fe(V)=O accounts for the experimentally observed incorporation of solvent water into the products. An investigation of the possible hydroxylation of acetonitrile (i.e., the solvent used in the experiments) shows that the activation energy for hydrogen-atom abstraction by HO-Fe(V)=O is rather high and, in fact, rather similar to that of methane, despite the similarity of the H-CH(2)CN bond strength to that of the secondary C-H bond in propane. This result indicates that the kinetics of hydrogen-atom abstraction are strongly affected by the cyano group and rationalizes the lack of experimental evidence for solvent hydroxylation in competition with that of substrates such as cyclohexane. 相似文献