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H2O2氧化降解海藻酸钠 总被引:1,自引:0,他引:1
研究了清洁高效的氧化剂H2O2对海藻酸钠的降解,探讨了溶液pH值、反应温度、H2O2用量及金属离子浓度对降解速度的影响. 结果表明,随着溶液pH值的降低、反应温度的升高及H2O2用量的增加,降解速度加快. 当反应pH=5.3、反应温度50 ℃、H2O2用量0.5%时,反应2 h即可降低海藻酸钠的分子量. 4 mg/L的Cu2+或Fe2+可明显加快降解速度,反应30 min的粘度变化相当于不加Cu2+或Fe2+时300 min的变化. GPC结果表明,海藻酸钠被氧化降解后,分子量下降,分布变宽;FTIR显示降解前后海藻酸钠的糖环结构没有改变,主要是糖苷键的断裂. 相似文献
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《European Journal of Solid State and Inorganic Chemistry #》1998,35(10-11):699-706
The bis(cyclopropylammonium)dihydrogenodiphosphate monohydrate is a new diphosphate associated with the organic molecule C3H5NH2. We report the chemical preparation and the crystal structure of this organic cation diphosphate. (C3H5NH3)2H2P2O7.H2O is orthorhombic (S.G. : P212121), with Z = 4 and the following unit-cell parameters : a = 4.828(1) Å, b = 11.011(1) Å, c = 25.645(2) Å. The P2O7 groups and H2O water molecules form a succession of bidimensional layers perpendicular to the c axis. The organic cations ensure the three-dimensional cohesion by NH-O hydrogen bonds. 相似文献
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《Journal of Coordination Chemistry》2012,65(11):967-973
Reaction of a freshly prepared Ni(OH)2?2 x (CO3) x ·yH2O with maleic acid in H2O at room temperature afforded [Ni(H2O)6][Ni(H2O)2(C4H2O4)]·4H2O, which consists of [Ni(H2O)6]2+ cations, [Ni(H2O)2(C4H2O4)]2? anions and lattice H2O molecules. Ni atoms in cations are octahedrally coordinated and Ni atoms in anions are each octahedrally coordinated by bidentate chelating maleato ligands and two water molecules at trans positions. Cations and anions are interlinked by hydrogen bonds to form 1D chains, which are hexagonally arranged and connected by the lattice water molecules. When heated in a flowing argon stream, the compound decomposes, with complete dehydration being followed by dissociation of nickel maleate into NiO and maleic anhydride. 相似文献
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《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1990,46(3):419-424
The infrared, Raman and inelastic neutron scattering (INS) spectra of TSA·6H2O and TPA·6H2O are in agreement with those expected for the presence of H5O+2 ions. Force fields for different assignment schemes are compared with the observed vibrational frequencies and the INS spectral profile. All but two schemes are eliminated. Whilst low-resolution INS spectroscopy cannot distinguish between these two schemes, the orientations of the vibrational ellipsoids for one scheme are in better agreement with those reported from low-temperature crystallographic studies of the H5O+2 ion. 相似文献
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B. L. Kuzin S. M. Beresnev A. V. Bannykh M. V. Perfil’yev 《Russian Journal of Electrochemistry》2000,36(4):424-430
In the temperature range 873–1123 K, transport numbers of oxygen ions and protons are determined in the system (H2 + H2O), Me/BaCe0.9Nd0.1O3-α/Me,(H2 + H2O), where Me = Ag, Au, Pt, Ni, by the emf and current methods. The determined transport numbers are independent of the determination
method, the electrode material, the current direction (anodic and cathodic polarization of the electrode), polarizability
of electrodes, and the partial water (hydrogen) pressure in the gas phase. This unambiguously suggests that the transport
numbers refer to the solid electrolyte, and not the electrochemical system as a whole. It also follows that partial currents
of the hydrogen ionization and the oxygen ion discharge are determined by the transport numbers of protons and oxygen ions
in the electrolyte. At a constant temperature, their ratio is affected by neither the electrode potential nor the gas phase
composition, i.e., both electrode reactions have a common limiting step (or steps).
Deceased. 相似文献
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X. F. Wang Y. F. Wang J. Wang Zh. H. Zhang J. Gao B. Liu Y. Ch. Jiang X. D. Zhang 《Russian Journal of Coordination Chemistry》2008,34(8):555-563
The title complexes, K3[Cd(Dtpa)] (H5Dtpa = diethylenetriamine-N,N,N,N′,N′-pentaacetic acid, (I)), K2[Cd(H2O)4][Cd(Edta)(H2O)]2 · 2H2O (H4Edta = ethylenediamine-N,N,N′,N′-tetraacetic acid, (II)), and Na2[Cd(H2O)4][Cd(Edta)(H2O)]2 · 2H2O (III), were prepared, and their compositions and structures were determined by elemental analyses, IR spectra, and single-crystal X-ray diffraction techniques, respectively. In complex I, the Cd is seven-coordinated by one Dtpa ligand yielding a pseudo-monocapped trigonal prism conformation, and the complex crystallizes in the triclinic crystal system with the Pi space group. The crystal data are as follows: a = 8.7300(17), b = 9.1200(18), c = 15.110(3) Å, α = 95.52(3)°, β = 96.59(3)°, γ = 99.63(3)°, V = 1170.0(4) Å3, Z = 2, ρ = 1.754 g/cm3, μ = 1.519 mm?1, F(000) = 616, R = 0.0644 and wR = 0.1712 for 3842 observed reflections with I ≥ 2σ(I). For complex II, in the [Cd(Edta)(H2O)]2? complex anion the Cd2+ ion is seven-coordinated by one Edta ligand and one water molecule, yielding a pseudo-pentagonal bipyramid conformation. In the [Cd(H2O)4]2+ cation, the bridged Cd is six-coordinated, yielding an almost standard octahedral conformation. The complex crystallizes in the monoclinic system with P21/n space group. The crystal data are as follows: a = 9.098(3), b = 16.442(6), c = 12.023(4) Å, β = 91.053(6)°, V = 1798.3(12) Å3, Z = 2, ρ = 2.098 g/cm3, μ = 2.086 mm?1, F(000) =1124, R = 0.0406 and wR = 0.1152 for 3680 observed reflections with I ≥ 2σ(I). In complex III, the conformations of Cd2+ ions are similar to those of the potassium salt complex, and the complex also crystallizes in the monoclinic crystal system with the P21/n space group. The crystal data are as follows: a = 9.134(7), b = 16.500(13), c = 12.075(10) Å, β = 91.054(12)°, V = 1820(2) Å3, Z = 2, ρ = 2.015 g/cm3, μ = 1.856 mm?1, F(000) = 1092, R = 0.0363 and wR = 0.0879 for 3707 observed reflections with I ≥ 2σ(I). 相似文献
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Yu. A. Ferapontov M. A. Ul’yanova T. V. Sazhneva 《Russian Journal of Inorganic Chemistry》2008,53(10):1635-1640
The decomposition kinetics of peroxide products contained in the liquid phase of the LiOH-H2O2-H2O ternary system were studied, and the applicability of the solubility method to studying this system was demonstrated for hydrogen peroxide concentrations in the liquid phase from 2 to 6 wt % and temperatures of 21–33°C. The stabilizing influence of solid Li2O2 · H2O on hydrogen peroxide decomposition was demonstrated. The temperature and concentration boundaries of existence were determined for the Li2O2 · H2O phase, whose identity was verified by chemical analysis and qualitative X-ray powder diffraction analysis. 相似文献
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Shilov G. V. Nikitina Z. K. Dobrovolskii Yu. A. Leonova L. S. Chernyak A. V. Tarasov V. P. Atovmyan L. O. 《Russian Journal of Coordination Chemistry》2004,30(11):759-764
Single crystals of the Rb4H2I2O10· 4H2O were synthesized for the first time and studied by X-ray diffraction analysis. The crystals are monoclinic, a = 7.321(6) Å, b = 12.599(8) Å, c = 8.198(8) Å, = 96.30(7)°, Z = 2, space group P21/c. The H2I2O10
4– anion is formed by the edge-sharing IO6 octahedra. The anions are united by hydrogen bonds into a chain running along the x axis. The chains are combined by water molecules into a three-dimensional structure through hydrogen bonds. The compound is a proton conductor. The conductivity values measured at 20–60°C vary within 10–6 to 10–4 ohm–1 cm–1. 相似文献
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S. V. Larionov L. I. Myachina L. A. Glinskaya I. V. Korol’kov E. M. Uskov O. V. Antonova V. M. Karpov V. E. Platonov V. P. Fadeeva 《Russian Journal of Coordination Chemistry》2012,38(12):717-723
Compounds p-HOOCC6F4COOH · H2O (H2L · H2O), [Tb2(H2O)4(L)3 · 2H2O] n (I), and Tb2(Phen)2(L)3 · 2H2O (II) are synthesized. According to the X-ray structure analysis data, the crystal structure of H2L · H2O is built of centrosymmetric molecules H2L and molecules of water of crystallization. The crystal structure of compound I is built of layers of coordination 2D polymer [Tb2(H2O)4(L)3] n and molecules of water of crystallization. The ligands are the L2? anions performing both the tetradentate bridging and pentadentate bridging-chelating functions. The coordination polyhedron TbO9 is a distorted three-capped trigonal prism. Acid H2L manifests photoluminescence in the UV region (??max = 368 nm). Compounds I and II have the green luminescence characteristic of the Tb3+ ions, and the band with ??max = 545 nm (transition 5 D 4?? 7 F 5) is maximum in intensity. The photoluminescence intensity of compound II is higher than that for compound I. 相似文献
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H2NCH2CN+H2O→H2NCH2C(OH)NH是一个重要的反应, 涉及到星际媒介中甘氨酸的形成, 与早期地球上的氨基酸起源有关. 如果没有考虑氢隧道效应, 在MP2/6-311+G(d,p)级别上计算反应能垒是254.7 kJ·mol-1, 在星际媒介中该气相反应很难进行. 在星际媒介冰颗粒表面上, 水分子催化反应增强了该化学反应的活性. H2NCH2CN与(H2O)3反应中的两个水分子作为催化剂降低活化能77.5 kJ·mol-1和活化自由能70.9 kJ·mol-1, 并且通过氢键桥协同传递质子. 量子氢隧道对于该反应进行至关紧要,采用小弯曲隧道(SCT)近似和正则变分过渡态理论(CVT)方法研究. 温度50 K时, 速率常数kSCT/CVT为1.86×10-23 cm3·molecule-1·s-1, 表明在星际媒介中通过质子隧道机理该反应容易进行. 研究结果与地球上的氨基酸起源于地球本身物质的观点相一致. 相似文献
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In a previous work (ref. 1) we observed important changes in the 1700–1400 cm−1 region of FTIR spectra in 2H2O solutions when 5′-GMP concentration increases. These changes can be attributed to the self-association of this mononucleotide. Recently, study of this process has been extended to other regions of the spectrum and to H2O solution. Fourier deconvolution has been employed in order to resolve the broad band into component bands. Differences have been observed between spectra in H2O and 2H2O for the same solute concentration. The possible causes of these differences are indicated. 相似文献