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1.
The stable phase equilibria of quaternary systems LiBr-NaBr-MgBr2-H2O and LiBr-KBr-MgBr2-H2O at 298.15 K were studied by both experimental measurement(isothermal solution saturation method) and theoretical prediction(Pitzer model). The solubilities of the saturated solution have been determined experimentally and two stable phase diagrams and relevant water diagrams of the two quaternary systems were obtained. Results show that quaternary system LiBr-NaBr-MgBr2-H2O is hydrate II type as NaBr and NaBr·2H2O coexistence. Its phase diagram consists of only one invariant point, four univariant curves, and five crystallization fields. The quaternary system LiBr-KBr-MgBr2-H2O is a complex type as the double salt KBr·MgBr2·6H2O formed. In addition to this double salt, the three single salts LiBr·2H2O, KBr and MgBr2·6H2O also crystallize. In this paper, the solubilities of phase equilibria in above quaternary systems were also calculated by the Pitzer's electrolyte solution model. All the needed parameters can be obtained from the literature or be fitted by experimental data. On the Basis of the experimental and calculated results, the phase diagram of the quaternary system was plotted for comparison. It shows that the calculation results are consistent with the experimental ones. 相似文献
2.
Jilly James Chidambaram Ramalechume Asit Baran Mandal 《Journal of Polymer Science.Polymer Physics》2007,45(17):2410-2420
The shape, size, aggregation, hydration, and correlation times of water insoluble PEO‐PPO‐PEO triblock copolymer micelles with sodium dodecylsulfate (SDS) micelles were investigated using transport studies and dynamic light scattering technique. From the conductance of micellar solutions of the polymer in 25 mM SDS and 5 mM NaCl, the hydration of polymer micelles were determined using the principle of obstruction of electrolyte migration by the polymer. The asymmetry of the micellar particles of polymer and polymer‐SDS mixed micellar systems in 5 mM NaCl and their average axial ratios were calculated using intrinsic viscosity and hydration data obeying Simha–Einstein equation. Hydration number and micellar sizes were variable with temperature. The shape of the polymer micelles has been ellipsoidal rather than spherical. The micellar volume, hydrodynamic radius, radius of gyration, diffusional coefficients as well as translational, rotational and effective correlation times have been calculated from the absolute values of the axes. The partial molal volume of polymer micelles has also been determined and its comparison with the molar volume of pure polymer suggested a volume contraction due to immobilization of the water phase by the hydrophilic head groups of the polymer. The thermodynamic activation parameters for viscous flow favor a more ordered water structure around polymer micelles at higher temperatures. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2410–2420, 2007 相似文献
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基于在磷酸介质中溴对溴酸钾氧化丁基罗丹明B反应的抑制作用,建立了痕量溴的阻抑动力学荧光分析的新方法;应用单纯形最优化法确定了 实验条件,方法的检出限0.075μg/L,线性范围0.40-6.40μg/L;将该法应用于地下水、人发中溴的分析,获得满意结果,并对反应机理进行了初步探讨。 相似文献
5.
Stationary phase properties of the organic molten salt ethylpyridinium bromide in gas chromatography
Summary The organic molten salt, 1-ethylpyridinium bromide, is suitable for use as a stationary phase in gas chromatography. It has a usable liquid temperature range of 110 to 160°C. It undergoes a single phase transition at 110°C which corresponds to the bulk melting point. Below the melting point the phase may be used as a selective adsorbent, although column efficiency and peak symmetry deteriorate as the temperature is lowered from the melting point. Above the melting point, ethylpyridinium bromide can be used to separate a wide variety of organic compounds retaining strongly those compounds possessing large dipole or hydrogen bonding functional groups. 相似文献
6.
Christian Lherbet 《Tetrahedron letters》2005,46(20):3565-3567
The treatment of trialkyl phosphate with different alkyl bromides provides facile access to mixed phosphate esters. The presence of substoichiometric amounts of lithium bromide was found to be critical to this transesterification process, supporting a mechanism involving initial generation of phosphate anion, followed by its nucleophilic attack on alkyl bromide. 相似文献
7.
对聚苯醚(PPO)进行了苯环溴代、甲基溴代以及胺交联,发现苯环溴代可提高O_2、N_2透过率(P),而选择性(α)基本不变。甲基溴代则相反,P降低、α有明显提高。调节两者比例可得到P、α兼优的O_2、N_2分离膜。甲基溴代后进一步胺交联可得到α更高、耐溶剂的膜材料。 相似文献
8.
Grace‐Ann M. Lobo Sneha A. Chitre Spandan M. Rathod Robert B. Smith Ray Leslie Callum Livingstone James Davis 《Electroanalysis》2007,19(24):2523-2528
The exploitation of 2‐bromo‐1,4‐naphthoquinone (NQBr) as a selective redox label for the determination of reduced thiol functionalities (RSH) has been investigated. The system is selective for RSH functionality, giving distinct voltammetric signals for glutathione and cysteine but can also be adapted for broad spectrum thiol detection. Ion chromatographic protocols based on conductimetric detection enable total RSH analysis (protein and monomolecular moieties) within human plasma. Bromide released through the reaction can be easily quantified and integrated within normal IC measurements. The efficacy of the approach has been assessed and the response validated through comparison with the standard colorimetric technique. 相似文献
9.
Ag+、Hf2+与Tl3+对Belousov-Zhabotinskii反应影响的初步研究 总被引:1,自引:0,他引:1
本文初步研究TAg+、Hg’十与T13十对以Mh‘十为催化剂的B-Z反应的影响,观察这些Br’去除离子存在下的极投环行为,并对其机理进行初步研讨.按照FKN机理同,B-Z反应是受Br一控制的.1979年N。SZtiCZills将适量的Ag十加入B·Z反应系统,澳离子选择电极上振荡虽被抑制了,但拍电极上却出现频率更高的振荡问.由于Ag十与Bt一生成了AgBr沉淀,使系统的[Br则降至其临界值以下,因此,Noszticzius认为不可能是Br控制的,FKN机理不再适用.1981年K5rs。等人报导了能与Br一形成稳定配合物的Hg‘十与T户十对B-Z反应的影响[3]… 相似文献
10.
Bromide and iodide ions were determined simultaneously by capillary isotachophoresis using an aqueous electrolyte system; the separation principle was based on the ion-pairing equilibria between tetradecyldimethylbenzylammonium ion and these anions in the leading electrolyte. The interaction between iodide ion and tetradecyldimethylbenzylammonium ion was stronger than that for bromide ion. Thus complete separation of bromide and iodide ions could be obtained by using a leading electrolyte containing 1.5 mM tetradecyldimethylbenzylammonium ion. The pH of the leading electrolyte was adjusted to 5.0. The relative standard deviations of the zone length for bromide and iodide ions were 1.1 and 1.2%, respectively, when mixture of 3.0 mM of these ions was analysed. A 150-μl volume could be injected for the simultaneous determination of low concentrations of bromide and iodide ions. 相似文献