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111.
112.
Experimental and Theoretical Study of Hydrogen Atom Abstraction from C2H6 and C4H10 by Zirconium Oxide Clusters Anions 下载免费PDF全文
The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H- and Zr3O7H- are observed after the reaction. Den-sity functional theory calculations indicate that the hydrogen abstraction is favorable in the reaction of Zr2O5- with C2H6, which supports that the observed Zr2O5H- and Zr3O7H- are due to hydrogen atom abstraction from the alkane molecules. This work shows a newpossible pathway in the reaction of zirconium oxide cluster anions with alkane molecules. 相似文献
113.
Robert D. Lousenberg Molly S. Shoichet 《Journal of polymer science. Part A, Polymer chemistry》2000,38(8):1344-1354
Two novel trifluorovinyl ether (TFVE) monomers were copolymerized with either ethyl vinyl ether (EVE) or vinyl acetate (VAc) in a redox‐initiated aqueous emulsion: 1‐(2‐phenoxyethoxy)‐1,2,2‐trifluoroethene (Ph‐TFVE) and 1‐[2‐(2‐ethoxyethoxy)ethoxy]‐1,2,2‐trifluoroethene (Et‐TFVE). Previous studies demonstrated a propensity for radical hydrogen abstraction from the oligoether pendant group during the homopolymerization of Et‐TFVE with continued propagation of the resulting radical, thereby providing the rationale to investigate the copolymerization of our new TFVEs with EVE or VAc. Reactivity ratios were estimated using the error‐in‐variables model from a series of bulk free radical copolymerizations of Ph‐TFVE with EVE or VAc. The reactivity ratios were rPh‐TFVE = 0.25 ± 0.07, rEVE = 0.016 ± 0.04; rPh‐TFVE = 0.034 ± 0.04, rVAc =0.89 ±0.08. Partial hydrolysis of polymers containing VAc to vinyl alcohol (VA) resulted in two terpolymers: poly(Ph‐TFVE‐co‐VAc‐co‐VA) and poly(Et‐TFVE‐co‐VAc‐co‐VA), respectively. We investigated the possibility of hydrogen abstraction from VAc during polymerization by comparing the molar mass before and after hydrolysis. Abstraction from VAc was not apparent during polymerization; however, abstraction from the oligoether pendant group of Et‐TFVE was again evident and was more significant for those copolymers having a greater fraction of Et‐TFVE in the monomer feed. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1344–1354, 2000 相似文献
114.
Branko S. Jursic 《International journal of quantum chemistry》1999,71(6):481-490
High levels of ab initio calculations were performed with the target of exploring the potential‐energy surface for the doublet and the quartet nitrogen with methane. There is a considerable difference between these two reaction paths in light of the formation of the reactant complex. Doublet nitrogen is an excited state of nitrogen, but it forms a stronger complex with methane, making the activation barrier with the doublet and quartet nitrogen reaction with methane. Activation barriers, heats of the reaction, and bond dissociation energies for minima located in the potential surface of nitrogen and methane transformations into the hydrogen radical and H2CNH were evaluated, and the most probable reaction pathways were suggested. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 71: 481–490, 1999 相似文献
115.
Ab initio calculations on fluoroethane reactions with the hydroxyl radical have been carried out at different levels of theory. The convergence of reaction barriers and reaction enthalpies has been systematically investigated with respect to the size and quality of the basis set and the treatment of correlation energy. The G2 and MP2 barrier heights and reaction enthalpies show the best agreement with the experimental data. The split valence basis sets of triple-zeta quality supplemented by diffuse and polarization functions are necessary to reproduce experimental values for barrier heights and reaction enthalpies at the MP2 level of theory. The full counterpoise correction was used to calculate the basis set superposition error for several standard basis sets, including polarization and diffuse functions. The smallest counterpoise corrections are associated with basis sets that contain polarization and diffuse functions, the diffuse functions being the most effective in reducing BSSE. However, in our case, the uncorrected barrier heights are in better agreement with experimental results than the counterpoise-corrected data. Thus, at the MP2 level of theory, which seems to be dictated for larger electronic systems of chemical interest, the optimal approach is to increase the basis set to the maximum size affordable and to use results without counterpoise corrections for the calculation of reaction barriers. A viable alternative is the use of G2 theory because its results for the barrier heights and reaction enthalpies are in excellent agreement with the experimental data. © 1997 John Wiley & Sons, Inc. J Comput Chem 18: 1190–1199 相似文献
116.
Motoki Okaniwa Yoshihisa Ohta 《Journal of polymer science. Part A, Polymer chemistry》1997,35(13):2607-2617
The influence of radical initiators upon the emulsion graft copolymerization of styrene and acrylonitrile onto poly(dimethylsiloxane) (PDMS) was studied. As initiators, a series of peroxides and hydroperoxides were coupled with ferrous sulfate, among which the tert-butyl peroxylaurate system gave the highest grafting efficiency (30%). The tert-butyl peroxylaurate initiator fulfills the criteria for efficient radical grafting by generating only the tert-butoxy radical, which is reluctant to form a carbon radical via β-scission, being highly hydrophobic, and not carrying a tertiary hydrogen that may be abstracted by a radical. 13C-NMR analysis of the products showed that the grafting occurred on the silylmethyl groups of PDMS to give 10–25 grafts per polymer and graft ratio in the range 44–140%. The PDMS graft copolymers thus obtained could be used as surface-modifying agents to improve the lubricity and water-repellency of ABS [poly(styrene-co-acrylonitrile)-graft-polybutadiene]. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2607–2617, 1997 相似文献
117.
118.
We study the role of the Jacobian arising from a constraint enforcing the nonlinear relationg=V, where ,g, andV are the mass density, the momentum density, and the local velocity field, respectively, in the field-theoretic formulation of the nonlinear fluctuating hydrodynamics of simple fluids. By investigating the Jacobian directly and by developing a field-theoretic formulation without the constraint, we find that no changes in dynamics result as compared to the previous formulation developed by Das and Mazenko (DM). In particular, the cutoff mechanism discovered by DM is shown to be a consequence of the 1/ nonlinearity in the problem, not of the constraint. The consequences of this result for the static properties of the system are also discussed. 相似文献
119.
Oliver Buttler Amal Al‐Fawaz Deborah L. Kays Joanna K. Day Li‐Ling Ooi Simon Aldridge 《无机化学与普通化学杂志》2006,632(14):2187-2189
Halide abstraction from [(Ph3P)2Rh(μ‐Cl)]2 by the sodium salt of the weakly coordinating [BArf4]? anion [Arf = C6H3(CF3)2‐3,5] in the presence of excess arene offers a convenient, high‐yielding route to the half‐sandwich cations [(arene)Rh(PPh3)2]+[BArf4]? [arene = benzene ( 1 ), toluene ( 2 )]. Crystalline samples of 1 and 2 are isomorphous [a = 13.1270(2), b = 15.3030(2), c = 17.5760(3) Å, α = 74.620(1), β = 81.533(1), γ = 88.540(1)° for 1 ] and feature the arene ligand bound to the rhodium atom in η6 fashion. 相似文献
120.
由全氟(2-丙氧基丙酰)过氧化物[n-C3F7OCF(CF3)COO]2与亚硝酸钠制得新型的“魔蓝”试剂[n-C3F7OCF(CF3)]2N(O)(1)和n-C3F7OCF(CF3)NO2的F113(CCl2FCClF2)溶液,在室温下与一系列对位取代苯甲醛(3)发生攫氢/自旋截捕反应,生成稳定的全氟(1-丙氧基乙基)对位取代苯甲酰基氮氧自由基(4).由自由基4的超精细偶合常数αN和αFβ与取代基的Hammett极性参数和自旋离域参数的相关分析得知,虽然自旋离域因素影响αN值,但取代基的极性是决定αN值的主要因素. 相似文献