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91.
C. Carlier-Pinasseau A. Astruc G. Lespes M. Astruc 《Journal of chromatography. A》1996,750(1-2):317-325
A reliable and rapid speciation method for the simultaneous determination of butyl- and phenyltin species in biological samples has been developed. Three extraction procedures are compared: enzymatic hydrolysis and solubilization by ethanoic and hydrochloric acids. Derivatization is performed by the one-step ethylation/extraction procedure using the sodium tetraethylborate reagent directly in the aqueous phase in the presence of an isooctane layer. Analysis is performed using capillary gas chromatography coupled to flame photometric detection. The detection limits are in the range of a few ng(Sn)/g. Analysis of the environmental samples and the certified reference material demonstrates the accuracy of the analytical method. 相似文献
92.
Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO_3 under solvent free oxidation at room temperature. 相似文献
93.
94.
Two New Metatitanates with Five-coordinated Titanium: CsNaTiO3 and RbNaTiO3 [1] The new oxides CsNaTiO3 (I) and RbNaTiO3 (II) are obtained by heating well grounded mixtures of the binary oxides in Ni-tubes as colourless platelike crystals. I: CsO0.56, NaO0.48 and TiO2, Cs:Na:Ti = 1.1:1.1:1.0; 600°C, 61 d as well as CsO0.97, NaO0.48 and Ti2O3, Cs:Na:Ti = 1.5:3.0:1.0; 760°C, 27 d. II: RbO0.52, NaO0.48 and TiO2, Rb:Na:Ti = 1.1:1.1:1.0; 750°C, 14 d as well as RbO0.98, NaO0.48 and Ti2O3, Rb:Na:Ti = 1.5:3.1:1.0; 760°C, 27 d. CsNaTiO3 (orthorhombic, Cmcm) is nearly isostructural with KNaTiO3 [2]; a = 601.4(1) pm, b = 1 120.3(1) pm, c = 563.4(1) pm (Guinier-Simon-Data, Z = 4). RbNaTiO3 (monoclinic, C2/c) is isostructural with KNaTiO3; a = 590.3(1) pm, b = 1 098.4(1) pm, c = 555.1(0) pm, β = 92.15° (Guinier-Simon-Data, Z = 4). Both structures are determined by using four-circle diffractometer data (CsNaTiO3: Siemens AED2, 2 896Io(hkl), MoKα , R = 2.4%, Rw = 2.3%; RbNaTiO3: Philips PW 1 100, 2 743Io(hkl), AgKα , R = 9.9%, Rw = 8.9%; additional data see text). The Madelung Part of Lattice Energy (MAPLE), Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR) and the Charge Distribution in Solids are calculated and discussed. 相似文献
95.
96.
蒙脱石是具有2∶1层状结构的粘土矿物,酸化蒙脱石用途广泛[1]。利用较大体积多聚金属阳离子与蒙脱石进行离子交换并把蒙脱石层撑开,可以得到复合材料—层柱蒙脱石(PILM),它具有二维的层柱结构,其孔径比一般的分子筛大。其孔径还可以根据蒙脱石离子交换当量和交换阳离子的体积大小加以控制。它具有良好的热稳定性和酸性,并且合成方法简单。蒙脱石和膨润土在我国分布广泛,储量大。因此PILM在载体、吸附剂及较大分子转化催化剂等方面具有较好的应用前景。传统的层柱蒙脱石是由单组分多聚金属阳离子与蒙脱石进行交联而合成的,本文在… 相似文献
97.
Shouhong Xu Yuan Song Shizuko Sato Isamu Miyata Junpei Yamanaka Masakatsu Yonese 《Colloid and polymer science》2005,283(4):383-392
Two-dimensional structures and characteristics of the complexes between sodium hyaluronate (NaHA) and bovine serum albumin (BSA) were studied by using a quartz crystal microbalance method and an atomic force microscope (AFM). NaHA did not adsorb on poly(-methyl-l-glutamate) (PMLG) film. On the other hand, the complexes adsorbed on it and the adsorption behaviors were found to be Langmuir types. With increasing weight ratio of BSA to NaHA, W
BSA, the adsorption constants K decreased and the saturated adsorption masses increased. The adsorbed complexes were spherical particles and at saturated adsorption states they covered compactly on the PMLG film. The mean diameters d
AFM estimated from the topographic images decreased from 70 to 54 nm with increasing W
BSA. The adhesion force F
ad and the frictional force F
f between the complex layers and the AFM tip were obtained by using the contact mode of the AFM. With increasing W
BSA, the values of F
ad decreased and the values of F
f increased. Compared with the frictional coefficient of the NaHA adsorption layer on the BSA monolayer, the values for the NaHA–BSA complex layer were found to be much higher. 相似文献
98.
G. Rytwo R. Huterer-Harari S. Dultz Y. Gonen 《Journal of Thermal Analysis and Calorimetry》2006,84(1):225-231
Adsorption
of erythrosin-B (EB) and fast green (FG) to a non-charged organosmectite based
on crystal violet adsorbed up to 100% of the cation exchange capacity (CEC)
was tested. Adsorption isotherms of EB and FG were prepared at 3, 24 and 50°C.
All isotherms are of H-type reaching loads of approximately up to 20% of the
original CEC of the crude montmorillonite (up to 0.15 and 0.10 mol dye kg–1
clay for EB and FG, respectively). Adsorption decreases with temperature,
indicating an exothermic process. Enthalpy was evaluated using van’t
Hoff equation, yielding approximately –20 kJ mol–1
for both dyes. 相似文献
99.
Sodium poly(styrenesulfonate)(polySSNa)-grafted polymer nanoparticles were synthesized by core-cross-linking of block copolymer micelles and subsequent chemical transformation. Block copolymers, poly(p-((1-methyl)silacyclobutyl)styrene-block-poly(neopentyl p-styrenesulfonate)s, polySBS-b-polySSPen, were synthesized by nitroxy-mediated living radical polymerization. The block copolymers formed micelles (Rh=15-23 nm, where Rh represents the hydrodynamic radius) with a polySBS core and polySSPen shell in acetone. The micelle core was cross-linked by ring-opening polymerization of silacyclobutyl groups in polySBS. Hydrolysis of the neopentyl groups provided polySSNa-grafted nanoparticles. The Rh of the particles before the hydrolysis ranged from 12 to 21 nm in acetone, while they varied to the range from 50 to 110 nm in water after the hydrolysis. 相似文献
100.
J. Bujdák H. Slosiariková B. Číčel 《Journal of inclusion phenomena and macrocyclic chemistry》1992,13(4):321-327
Reduced charge montmorillonites (RCM) were prepared using lithium thermal treatment. The sorption of octylammonium (OA), dodecylammonium (DDA) and hexadecylammonium ions (HDA) on differently charged samples were studied. The amounts of DDA and HDA sorbed on each RCM exceed the cation exchange capacity (CEC) but that of OA exceeds only the CEC of samples with the lowest CEC. The sorption is affected not only by the layer charge but also by the formation of collapsed interlayer spaces in the lowest charged montmorillonites. X-ray measurements confirmed the decrease of the layer charge after lithium thermal treatment and the layer charge heterogeneity in RCMs. 相似文献