TiO2颗粒表面包覆SiO2纳米膜的动力学模型

针对液相法二氧化钛颗粒表面包覆氧化硅纳米膜的过程,提出包覆过程是溶胶凝胶机制,研究了表面成膜的动力学方程,考察了成膜剂浓度和成膜过程中温度对成膜速度的影响,并通过实验对氧化硅膜形成的动力学方程进行了验证.     

镍-二甲酚橙-溴化十六烷基三甲铵动力学光度法测定镍

研究了Ni2+与二甲酚橙及溴化十六烷基三甲铵形成三元络合物的反应特性，测定了反应级数和表观活化能．基于该络合反应速率较小的特性，采用对数外推法计算机处理数据，建立了停流－动力学测定Ni2+的新方法．大多数元素的干扰均可用动力学方法消除，应用于镍矿等实样中镍的测定，结果满意，其相对标准偏差小于3％。     

Experimental determination of the liquidus of the binary system (Cu2O + CaO) in air at temperature from (1050 to 1500) °C

The liquidus of the binary system (Cu₂O + CaO) has been experimentally investigated over the temperature range from (1050 to 1500) °C in air. The liquidus has been quantified by the equilibration/quench/analysis technique. Equilibrated specimens were quenched in brine solution of 10 wt% NaCl. Specimens were then examined by Energy-Dispersive X-ray Spectroscopy (EDS) and Electron probe micro-analyzer (EPMA) to quantify liquid chemical compositions. This work reveals that the solubility of CaO in the liquid phase of the binary (Cu₂O + CaO) at higher temperatures is lower than previously reported, and the deviation systematically increases with a corresponding increase in temperature. This is predominant at temperatures between (1300 and 1500) °C where a deviation of up to 5 wt% in CaO solubility is observed. The solubility of Cu₂O in liquid phase for the cuprite saturated section of the binary however is consistent with all the previous authors.     

丙烯酰胺对Span80-Tween85/Isopar M/丙烯酰胺-H2O拟三元体系相行为的影响

考察了丙烯酰胺对水/IsoparM界面张力的影响以及对水溶液中非离子性乳化剂Tween85的助溶效果,并深入探讨了丙烯酰胺对Span80-Tween85/IsoparM/AM-H2O拟三元体系相行为的影响过程。结果表明,丙烯酰胺能够提高Tween85在水溶液中的溶解度,并可有效降低油水界面张力,进而能够扩大Span80-Tween85/IsoparM/AM-H2O拟三元相图的反相乳液区域面积。     

High-pressure phase equilibrium data for the (carbon dioxide + l-lactide + ethanol) system

Experimental phase equilibrium values (cloud points) for the ternary system involving carbon dioxide, l-lactide and ethanol have been measured in order to provide fundamental values to conduct the polymerization reaction in supercritical carbon dioxide medium. The experiments were performed using a variable-volume view cell over the temperature range from 323 K to 353 K, system pressure between 9 MPa and 25.0 MPa and different mole ratios of ethanol to l-lactide (0.5:1, 1:1 and 1.5:1). Phase transitions of vapour-liquid types were observed. The experimental results were modelled using the Peng–Robinson (PR) equation of state with the Wong–Sandler (PR–WS) mixing rule, providing a good representation of the experimental phase equilibrium values.     

Measurement and modelling of binary (solid + liquid + vapour) equilibria involving lipids and CO2

The development of solid lipid nanoparticles (SLN) using supercritical fluid at room temperature is an innovative alternative compared to traditional pharmaceutical methods and the safety and drug efficacy of SLN made using supercritical CO₂ is increased. One of the micronization techniques which have provided the best results in the production of SLN is particles from gas-saturated solution (PGSS). The solid–liquid–vapour coexistence curve of a solid in a compressed gas is of primary importance in assessing the feasibility of PGSS and the selection of appropriate operating conditions. The objectives of this work are to perform experimental measurements using a high pressure differential scanning calorimeter (DSC) to obtain melting properties as a function of composition and develop a simplified approach to model multiphase equilibria of lipids in compressed CO₂. The selected lipid was tristearin. Before assessment of triestearin and CO₂ phase equilibrium, the performance of this thermodynamic model was evaluated in two other lipids which provided results with high accuracy.     

(Liquid + liquid), (solid + liquid), and (solid + liquid + liquid) equilibria of systems containing cyclic ether (tetrahydrofuran or 1,3-dioxolane), water,and a biological buffer MOPS

Two liquid phases were formed as the addition of a certain amount of biological buffer 3-(N-morpholino)propane sulfonic acid (MOPS) in the aqueous solutions of tetrahydrofuran (THF) or 1,3-dioxolane. To evaluate the feasibility of recovering the cyclic ethers from their aqueous solutions with the aid of MOPS, we determined experimentally the phase diagrams of the ternary systems of {cyclic ether (THF or 1,3-dioxolane) + water + MOPS} at T = 298.15 K under atmospheric pressure. In this study, the solubility data of MOPS in water and in the mixed solvents of water/cyclic ethers were obtained from the results of a series of density measurements, while the (liquid + liquid) and the (solid + liquid + liquid) phase boundaries were determined by visually inspection. Additionally, the tie-line results for (liquid + liquid) equilibrium (LLE) and for (solid + liquid + liquid) equilibrium (SLLE) were measured using an analytical method. The reliability of the experimental LLE tie-line results data was validated by using the Othmer–Tobias correlation. These LLE tie-line values were correlated well with the NRTL model. The phase diagrams obtained from this study reveal that MOPS is a feasible green auxiliary agent to recover the cyclic ethers from their aqueous solutions, especially for 1,3-dioxolane.     

PrCl3—SrCl2—NaCl三元体系相图的研究

借助于DTA和X射线结构分析研究了PrCl_3-SrCl_2-NaCl三元体系相图,发现本体系内有对应于PrCl_3、SrCl_2、NaCl和Sr_3PrCl_9的4个液相面、5条二次结晶线、1个三元低共熔点E(PrCl_3 68.1,SrCl_2 1.1,NaCl 30.8 wt％;465℃)和三元转熔点P(PrCl_3 65.0,SrCl_2 7.0,NaCl 28.0 wt％;515℃).同时发现有1个固相下形成的不稳定化合物Y(在440℃分解).     

NdCl_3-BaCl_2-NaCl三元体系相图的研究

借助于DTA和X射线衍射分析方法,研究了NdCl_3-BaCl_2-NaCl三元体系相图,发现本体系存在对应于NdCl_3、NaCl、α-BaCl_2、β-BaCl_2和Ba_3NdCl_9的5个液相面。6条二次结晶线,1个三元低共熔点E和三元转熔点P及一固相下形成的化合物。     

Ternary mutual diffusion in aqueous (ethambutol dihydrochloride + hydrochloric acid) solutions

Ternary mutual diffusion coefficients measured by the Taylor dispersion method are reported for aqueous solutions of {ethambutol dihydrochloride (1) + HCl (2)} at 25 °C and various carrier solution compositions. Mutual diffusion coefficients estimated from limiting ionic conductivities using Nernst equations are used to discuss the composition dependence of the measured diffusion coefficients. ¹H NMR studies, combined with DFT calculations, confirm a fully extended conformation for the diprotonated form of the drug present under these conditions, and are consistent with an electrostatic mechanism for the strongly coupled diffusion of diprotonated ethambutol and HCl.     

RbNO3-C2H5OH-H2O三元体系的液-固相平衡及其性质

测定了RbNO₃-C₂H₅OH-H₂O 体系在25 ℃和50 ℃的等温平衡溶解度及饱和液的性质(密度和折光率). 绘制了相图, 计算了盐析率, 评价了盐析效果. 用经验公式分别对溶解度、密度和折光率进行了关联, 效果良好. 体系没有产生分层现象, 得到的平衡固相皆为无水铷盐, 没有新化合物或水合物生成.     

RbNO_3-C_2H_5OH-H_2O三元体系的液-固相平衡及其性质

测定了RbNO3-C2H5OH-H2O体系在25℃和50℃的等温平衡溶解度及饱和液的性质(密度和折光率).绘制了相图,计算了盐析率,评价了盐析效果.用经验公式分别对溶解度、密度和折光率进行了关联,效果良好.体系没有产生分层现象,得到的平衡固相皆为无水铷盐,没有新化合物或水合物生成.     

(Liquid + liquid) equilibria of ternary and quaternary systems with two hydrocarbons, an alcohol, and water at 303.15 K. Systems containing cyclohexane, benzene, ethanol, and water

Tie-line data for the water, ethanol, and cyclohexane [{w₁H₂O + w₂C₂H₅OH + (1−w₁−w₂)C₆H₁₂}] ternary system, where w is the mass fraction, was investigated at T=303.15 K. A quaternary system containing these three compounds and benzene {w₁C₂H₅OH + w₂C₆H₆ + w₃C₆H₁₂ + (1−w₁−w₂−w₃)H₂O} was also studied at the same temperature, while data on its other two partially miscible ternary systems were taken from the literature [the fourth {w₁C₂H₅OH + w₂C₆H₆ + (1−w₁−w₂)C₆H₁₂} is not partially miscible]. From our experimental results we conclude that this quaternary system presents a very small water tolerance and that phase separation could produce a considerable loss of C₂H₅OH drawn into the aqueous phase. On the other hand, the results also show that the aqueous phase generally contains a higher concentration of C₆H₆ than of C₆H₁₂. A comparison with other similar quaternary systems investigated in our laboratory was also made. The ternary experimental results were correlated with the UNIQUAC equation, and predicted with the UNIFAC group contribution method. As previously, the equilibrium data of the three ternary systems (including those taken from the literature) were used to determine interaction parameters for the UNIQUAC equation. These parameters were then averaged in order to predict equilibrium data of this quaternary system. The UNIFAC method was also used with the same purpose. The UNIQUAC equation appears to be more accurate than the UNIFAC method for this ternary system. However, this last model is slightly better for the quaternary system, as can be seen from the values of both residuals.     

Phase behaviour of pseudo-binary systems of pressurized ((propane + l,l-lactide)) at different ethanol to l,l-lactide mole ratios

This work reports phase equilibrium data of pressurized (propane + l,l-lactide) system at different ethanol to monomer mole ratios (9:1; 7:1; 5:1). Phase equilibrium experiments were accomplished in a high-pressure variable-volume view cell employing the static synthetic method. (Vapour + liquid) equilibrium data for the pseudo-binary systems were determined within the temperature range from (323 to 353) K and pressures up to 3.3 MPa. For the systems investigated, (vapour + liquid) equilibrium (VLE) was visually recorded. It was observed that an increase in temperature or in propane concentration led to a pronounced rise in pressure transition values. On the other hand, an increase in the ethanol to l,l-lactide mole ratio led to a reduction in pressure transitions, whereas a reduction in ethanol concentration complicates the achievement of one-phase homogeneous system. Thus, rapid complete miscibility of the system can be controlled by the amount of ethanol added as a co-solvent. The experimental results were modelled using the Peng–Robinson (PR) equation of state with the Wong–Sandler (PR–WS) mixing rule, providing a good representation of the experimental phase transition points.     

Alkylations of Chiral Nickel(II) Complexes of Glycine under Phase‐Transfer Conditions

Alkylation reactions of nickel(II) complex 6 derived from glycine and 2‐[(1‐benzyl‐L ‐prolyl)amino]benzophenone (BPBP) were studied under phase‐transfer‐catalysis (PTC) conditions. The goal of this work was to find an alternative suitable solvent for these reactions to replace the commonly used CH₂Cl₂ which leads to the formation of several by‐products, thus lowering the yield of target compounds. We demonstrate that 1,2‐dichloroethane is a markedly better solvent providing higher yields (75–99%) of the desired products 10 with 36–88% diastereoisomer purity (Scheme 3 and Table). Furthermore, we show that the stereochemical outcome of these PTC reactions (kinetic control) can be easily improved to >95% de by treatment of the PTC products with MeONa/MeOH. The scope of these reactions includes alkylations with methyl iodide as well as activated halides such as benzyl, allyl or propargyl, bromides and most notably ethyl 2‐bromoacetate (Table).     

Sub-solidus phase equilibria in CeO2–SrO system

In this communication, we report on the synthesis and characterization of a series of compounds with the general composition Ce_1−xSr_xO_2−x (0.0≤x≤1.0), to establish a detailed phase relation in the CeO₂–SrO system. The X-ray diffraction (XRD) pattern of the each product was refined to determine the solid solubility and the homogeneity range. The solid solubility limit of SrO in CeO₂ lattice, under the slow cooled conditions, is represented as Ce_0.91Sr_0.09O_1.91 (i.e. 9 mol% of SrO). A careful delineation of the phase boundary revealed that the stoichiometric SrCeO₃, in fact, contains a little amount of CeO₂ also. The mono-phasic compound could be obtained at the nominal composition Sr_0.55Ce_0.45O_1.45. The nominal composition Sr₂CeO₄, under the heat treatment used in the present investigation, was a bi-phasic mixture of SrCeO₃ and SrO. No new ordered phases were obtained in this system.     

High-pressure phase behaviour of the binary system {CO2 + cis-decalin} from (292.75 to 373.75) K

The phase behaviour of the {CO₂ (1) + cis-decalin (2)} binary system has been experimentally studied at temperatures ranging from (292.75 to 373.75) K. Saturation pressures, ranging from (15.9 to 490.5) bar, were obtained using a variable volume high-pressure cell by visual observation of phase transitions at constant overall composition. For this system, no literature data are available and the results obtained in this study reveal the occurrence of vapor–liquid, liquid–liquid, and vapor–liquid–liquid phase transitions in the investigated temperature range. A total of 133 experimental points are reported including bubble points, dew points, liquid–liquid phase equilibria, and coordinates of the three-phase line. The experimental data can be reasonably predicted by the PPR78 model in which the temperature-dependent binary interaction parameter is calculated by a group contribution method.     

水-环己酮-甲基异丁基酮液液相平衡数据的测定与关联

为了给以甲基异丁基酮为溶剂含环己酮废水萃取过程的设计和流程模拟计算提供数据支撑,本文测定了常压下,水+环己酮+甲基异丁基酮（MIBK）三元体系在303.15、313.15及323.15 K的液液相平衡数据。据相平衡数据计算了分配系数和分离因子,所有的分离因子均远大于1,表明MIBK从水中萃取环己酮是可行的;Hand方程和Bachman方程的相关系数在0.99以上,表明实验数据具有较好的一致可靠性。同时,采用NRTL和UNIQUAC活度状态方程对实验数据进行了关联,回归得到了该三元物系的二元交互参数,结果表明两种模型均能很好关联实验数据,实验值和模拟值的相对均方根差（RMSD）低于0.5%。     

镍二亚胺配合物/烷基铝催化乙烯聚合

直链低碳α-烯烃是生产线性低密度聚乙烯的共聚单体及合成高级润滑油和一些精细化学品的中间体，通过乙烯齐聚反应生成直链α-烯烃是目前工业上重要的生产方法，近几年来使乙烯齐聚成α-烯烃的含二或三齿配体后过渡金属催化剂的催化特性受到人们很大的关注。