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71.
Vapor pressure,speciation, and chemical activities in highly concentrated sodium borate solutions at 277 and 317°C 总被引:2,自引:0,他引:2
Oleh Weres 《Journal of solution chemistry》1995,24(5):409-438
The system H2O-B2O3-Na2O has been studied experimentally at 277 and 317°C. The activities of water and boric acid have been determined at mole ratios Na/B from 0 to 1.5, and total dissolved solids 3 to 80 weight percent. The activity of boric acid has been fitted to within experimental error using a speciation model with eight complex species. This model is consistent with the model previously published by Mesmer et al. The electrolyte properties of the liquid are modeled using the Pitzer-Simonson model of very concentrated electrolyte solutions. The calculated values of water activity agree with experiment, and the activity of NaOH and pOH have also been calculated. The potassium borate system also was briefly studied at 317°C, and is adequately described by a model with five complex species. The potassium borate liquid is more alkaline at K/B= 1 than a sodium borate liquid at the same mole ratio, but pOH in the two systems is the same at lower mole ratios. 相似文献
72.
Atsushi Ikeda Masaru Kawaguchi Yoshio Suzuki Tsukasa Hatano Munenori Numata Seiji Shinkai Akio Ohta Makoto Ohta 《Journal of inclusion phenomena and macrocyclic chemistry》2000,38(1-4):163-170
The calixarene-fullerene interaction,which causes only a slight change in the absorptionspectra, has been substantiated by calorimetricmeasurements: the H° values arecomparable with those obtained from the associationconstants estimated by a spectroscopic method. Furthermore, we determined the association constantbetween homooxacalix[3]arene and [60]fullerenederivatives with a porphyrin moiety by fluorescencespectra. 相似文献
73.
The manganese(Ⅲ) complex [Mn(acacen){N(CN)2}]n [H2acacen=bis(acetylacetone)ethylenediimine] has been synthesized and the structure has been determined. The complex forms a one-dimensional chain structure via the bidentate bridge ligand μ1,5-[N(CN)2]- linking [Mn(acacen)] moiety. The magnetic property of the compound (75~300 K) shows the existence of an antiferromagnetic exchange interaction among paramagnetic centers along the chain. CCDC: 244940. 相似文献
74.
以十四酸根阴离子柱撑Zn-Al水滑石Zn0.77Al0.22(OH)2.0.22C13H27COO.0.81 H2O(记为ZnAl-14A)为预撑前体,在水溶液中用离子交换法将以2∶17缺位杂多酸根离子(P2Mo16VO61)11-记为(P Mo V)为配体的稀土杂多配阴离子Ce(P2Mo16VO61)219-(记为Ce(PMoV)2)插层组装到水滑石层板间,合成了一种具有大的层间距(3.37 nm)的超分子插层材料Zn0.77Al0.23(OH)2.0.0105[Ce(P1.9Mo15.7V1.1O61)2].0.011C13H27COO.0.83H2O(记为ZnAl-Ce(PMoV)2)。用ICP,IR,XRD和DTA对产物的组成和结构进行了表征。结果表明,该产物中Ce(PMoV)2配阴离子沿其长轴垂直于层板的方向分布于水滑石层间;产物具有规整的层状结构和热稳定性;产物对乙酸与正丁醇的酯化反应,二甘醇的脱水-环化反应和H2O2氧化环己烷的反应有良好的催化性能,且易于回收重复使用。 相似文献
75.
Naoya Inazumi Shunzo Yamamoto Yoshimi Sueishi 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(1-2):33-39
The inclusion complexation of p-sulfonatocalix[6]arene (Calix-S6) with three kinds of phenothiazine dyes was studied spectrophotometrically in a mixture
of a room-temperature ionic liquid [bmim]BF4 (1-butyl-3-methylimidazolium tetrafluoroborate) and ethanol. We have determined the association constants of Calix-S6 with
phenothiazine dyes under external static pressure up to 767 bar in the [bmim]BF4-ethanol and alcohol-water mixtures. With increasing external pressure, the inclusion equilibrium in the alcohol-water mixtures
was shifted to the dissociation side. Conversely, the inclusion equilibrium of methylene blue (MB) and azure A (AA) in the
ionic liquid mixture was shifted to the association side. From the analysis of the pressure effects, the reaction volumes
ΔV for inclusion complexation were estimated as −7 to 9 cm3 mol−1 in the [bmim]BF4-ethanol mixture and 20–32 cm3 mol−1 in the alcohol-water mixtures. Based on the results, we have suggested that there is a competing complexation between the
included dye and [bmim]BF4 molecules in the ionic liquid. 相似文献
76.
77.
B. T. Ibragimov S. A. Talipov T. F. Aripov 《Journal of inclusion phenomena and macrocyclic chemistry》1994,17(4):317-324
The structures of gossypol complexes are extremely sensitive to the halogenomethane present as the guest; e.g. changing the number of Cl atoms in chloromethane derivatives changes the structure of the gossypol complex. The crystals of C30H30O8·CH2Cl2 are monoclinic, space groupC2/c,a=21.320(4),b=19.199(6),c=15.765(2)Å, =113.05(2)o,V=5916(2)Å3,Z=8,D
x=1.35 g/cm3,T=295 K. The structure has been solved by direct methods and refined to the finalR value of 0.084 for 1828 reflections. In the structure H-bonded gossypol molecules form columns, generating channels in the structure which are filled by guest molecules. After decomposition (desolvation) monocrystals of the complexes are conserved without destruction, in which there are rather wide and empty channels though slightly smaller than in the complex. An attempt is made to explain some peculiarities of the behavior of the gossypol polymorph formed on the basis of its structure with empty channels.
Supplementary data relevant to this article have been deposited with the British Library Publication No. SUP 82165 (17 pages). 相似文献
78.
Himansu Sekhar Sahoo S. Mahalakshmi Md. Hedayetullah Mir R. Raghunathan 《Tetrahedron letters》2007,48(5):761-765
A remarkable upfield shift of the pyα protons of complexed 2,2′-bipyridine in [cis-Pd(bpy)(NO3)2] is observed which is considered to originate from the anisotropic influence of suitably positioned coordinated nitrate anions around the Pd(II) centre of the molecule. A typical complexation-induced downfield shift is observed for the NH2 protons in [cis-Pd(en)(NO3)2] where ‘en’ stands for ethylenediamine. 相似文献
79.
Mössbauer parameters of frozen aqueous solutions of Sn(ClO4)2 in 0.5 M HClO4 did not change with the concentration of NaClO4, so that it was used to keep the ionic strength at the desired level. When NaCl was added into Sn(ClO4)2 solutions, isomer shift did not change, but quadrupole splitting did. Therefore, stability constants were calculated from the quadrupole splitting data, which were in good agreement with the published values. The observed spectra could be resolved into components. 相似文献
80.