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S. Munavalli D. K. Rohrbaugh G. W. Wagner F. R. Longo H. D. Durst 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):781-789
Microwave catalyzed reaction of a neat mixture of styrene oxide and H-dimethylphosphonate furnished dimethyl methylphosphonate, trimethylphosphate, phenylacetaldehyde, 1-methoxy-2-phenylethanol, 1-phenylethleneglycol, cis- and trans-1,3-diphenylcyclobutanes, hydrogen 1-(2-phenylethyl)methylphosphinate, (1-phenylethyl)dimethylphosphonate, and (1-phenylethyl)dimethylphosphonate via free radical processes. 相似文献
23.
Andrew L. Hector William Levason Mark E. Light Gillian Reid Kripasindhu Sardar Wenjian Zhang 《无机化学与普通化学杂志》2013,639(6):906-910
Crystalline CrOCl3 contains [Cl2OCr(μ‐Cl)2CrOCl2] molecules with two square pyramidal CrOCl4 units sharing a common edge and with the Cr–O arranged anti, a new structure type for transition metal MOX3 compounds. Crystals are monoclinic with space group P21/c, Z = 4, with a = 5.735(5), b = 13.738(7), c = 11.318(4) Å, α = 90°, β = 98.346(6)°, γ = 90°. Its IR and UV/Vis spectra are reported and compared with those of the C3v monomer found in the gas phase. Structures are also reported for M2[CrOCl5] (M = Cs or Rb) and show a pseudo‐octahedral anion. Cs2[CrOCl5] adopts a K2PtCl6‐type structure with [CrOCl5]2– ions randomly orientated, but Rb2[CrOCl5] is orthorhombic with space group Pnma with a = 13.6471(7), b = 9.9175(5), and c = 6.9562(4) Å. Rietveld refinement of the data on the rubidium salt gave Cr–O = 1.628(1), Cr–CltransO = 2.652(7), Cr–CltransCl = 2.239(8)–2.342(3) Å. Corresponding CrV oxide bromide species do not form. 相似文献
24.
Emmanuel Urandu Mapesa Ludwig Popp Wycliffe Kiprop Kipnusu Martin Tress Friedrich Kremer 《Soft Materials》2014,12(4):S22-S30
Broadband Dielectric Spectroscopy (BDS) is used to probe the molecular dynamics of Type A polymer, poly(cis-1,4-isoprene), when confined in the 1-dimensional (1D) exploring space of thin layers and the 2-dimensional (2D) constraining geometry of unidirectional anodic aluminum oxide (AAO) nanopores. For both cases, it was observed that the structural relaxation remains bulk-like in its mean relaxation rate, although the distribution of its relaxation times is broadened in 2D confinement. Furthermore, the fluctuation of the end-to-end vector is interrupted, with the 1D case being relatively less pronounced. By this clear-cut comparison, it is demonstrated that the effects of confinement on molecular dynamics depend, inter alia, on the dimensionality of the restricting space. 相似文献
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原位漫反射傅里叶变换红外光谱研究锰铁基催化剂上低温选择性催化还原反应机理简 总被引:4,自引:0,他引:4
采用自蔓延燃烧法制备了Ti0.9Mn0.05Fe0.05O2-δ催化剂,运用原位漫反射傅里叶变换红外光谱对该催化剂的NO和NH3稳态吸附以及NO和NH3瞬态反应进行了详细地分析与讨论. 结果表明,相比于Lewis酸性位,150℃时Brönsted酸性位吸附的NH3更具有SCR活性;与双齿硝酸盐和桥式硝酸盐相比,NO吸附产生的单齿硝酸盐是主要的中间物种;该SCR反应遵循Eley-Rideal和Langmuir-Hinshelwood机理,但以后者为主. 另外,O2的存在有利于NO的氧化和配位态NH3的活化. 相似文献
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本文报导了傅里哀变换红外发射光谱法研究多相氧化物催化剂的实验装置的建立及实验条件的考察。设计加工了一个温度范围宽,可在各种气氛和真空条件下原位研究氧化物催化剂的红外发射池。以MoO_3为例,考察了样品厚度,测试温度对发射光谱的影响。当样品量小于1mm·cm~(-2)时,随样品量增加,谱峰强度线性增加,但峰形不发生变化。当样品量高于1mg.cm~(-2)时,随样品量增加,谱图严重畸变。随样品温度升高,谱峰强度近似线性增加。并用该方法研究了MoO_3在还原和再氧化过程中表面氧物种的变化。结果表明桥式MO?O?Mo物种比端基Mo=O物种较易还原,再氧化时,Mo=O物种比Mo?O?Mo物种优先形成。 相似文献
29.
Metal nanoparticles are nanosized structures that have different potential applications in biological, chemical, medical, and agricultural fields because of their exotic characteristics. Their size ranges from 1 to 100 nm. Metal nanoparticles are either purer forms of metals (eg: Gold, Silver, Copper, Iron, etc.) or their compounds (eg: sulfides, hydroxides, oxides, etc.). Ionic liquids are generally used in the extraction of nanoparticles but they are challenging because of their indigent bio-degradability, bio-compatibility, and sustainability. So Deep Eutectic Solvent (DES) is reported as an alternative to ionic liquids in the formation of nanoparticles. The DESs are a complex of quaternary ammonium salts and hydrogen donors or metal salt. DESs contain higher non-symmetric ions which have lower lattice energy and hence they have a lower melting point. This research utilizes a novel DES (choline chloride – urea) as an effective solvent to produce mercuric sulfide (HgS), zirconium oxide (ZrO), manganese oxide (MnO), and copper oxide (CuO) nanoparticles. As a result, the production of these metal nanoparticles using Choline Chloride (C5H14ClNO) – Urea DES can be treated as a promising way in chemical manufacturing. The nanoparticles have been analyzed using Ultra Violet Spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Energy Dispersive X-Ray Analysis (EDAX). 相似文献
30.
K.B. Ibrahim W.-N. Su M.-C. Tsai A.W. Kahsay S.A. Chala M.K. Birhanu J.-F. Lee B.J. Hwang 《Materials Today Chemistry》2022
Developing oxygen evolution reaction (OER) electrocatalyst based on earth-abundant materials holds great promise for ascertaining water-splitting to surmount its deprived kinetics. In this regard, NiFe-LDH (layered double hydroxide) receives considerable attention owing to their layered structure. However, they still suffer from poor electronic conductivity and structural stability. We combined NiFe-LDH nanosheets with Magnéli phase Ti4O7 into a heterostructured composite. A series of analyses reveal that decorating Ti4O7 facilitates charge transfer to enhance the conductivity of NiFe-LDH-Ti4O7. During electrochemical measurement, Ni2+ is transformed to metastable Ni3+ (Ni (OH)→ NiOOH) before the OER onset potential. Thus, the presence of Ni3+ as the main active sites could improve the chemisorption of OH? to facilitate OER. As a result, the NiFe-LDH-Ti4O7 catalyst delivers as low as onset potential (1.43 V). Combining the holey structure (NiFe-LDH and Ti4O7) and the defect engineering generated on NiFe-LDH-Ti4O7 as a synergistic effect improves the OER performance. The inclusion of Ti4O7 in the composite leads to more vacancy sites, as evidenced by the extended X-ray absorption fine structure (EXAFS) analysis. The obtained defective structure with a low coordination environment would improve the electronic conductivity and facilitate the adsorption process of H2O onto metal cations, thereby increasing the intrinsic catalytic activity of NiOOH. The strong coupling of NiFe-LDH and Ti4O7 also increases the stability, and the heterostructured composite helps maintain the structural robustness of the LDH. 相似文献