Preferential solvation of pomalidomide,an anticancer compound,in some binary mixed solvents at 298.15 K

Preferential solvation of pomalidomide (PMD) was explored in dimethyl sulfoxide (DMSO)-dimethylformamide (DMF), DMSO-tetrahydrofuran (THF), DMSO-methanol (MeOH), DMSO-isopropanol, DMSO-water, water-DMF, water-THF, water-MeOH, and water–isopropanol binary mixed solvents at 298.15 K. Bosch-Rose model was utilized to determine the electronic transition energies (E_T) and other preferential solvation parameters, describing solute-solute and solute-solvent interactions. We found that λ_max situation shifted with dielectric constant of the pure solvents meaningfully. According to the obtained results, E_T enhanced and λ_max shifted to the lower wavelengths as the percentage of DMSO decreased in the binary mixtures, remarking the important role of DMSO for stabilizing the excited state (π^⁎) of PMD chromophore via efficient intermolecular solute-solvent interactions. In addition, the aqueous binary systems showed an optimum point for the E_T values as the percentage of water changed in the solutions. The local mole fraction of the solvents in the cybotactic region was also estimated to describe the specific and non-specific interactions in the systems.     

Insight into solute-solute and solute-solvent interactions of semicarbazide hydrochloride in water and D-glucose/D-sucrose+water solutions at temperatures (293.15 to 318.15) K

The solute-solute and solute-solvent interactions of drug semicarbazide hydrochloride with carbohydrates (D-glucose/D-sucrose) are investigated by using volumetric, viscometric and acoustic properties. The measurements of the densities ρ, ultrasonic speeds u, and viscosities η. of semicarbazide hydrochloride in 5% and 10% D-glucose/D-sucrose+water (w/w) solutions were carried out at temperatures (293.15-318.15) K and at pressure, p=101 kPa. The apparent molar volumes, V_ϕ, limiting apparent molar volumes,V_ϕ°, apparent molar compressibilities, K_{s, ϕ}, limiting apparent molar compressibilities, K_s,ϕ°, partial molar expansibilities, E_ϕ°, transfer volumes, V_ϕ,tr° and transfer compressibilities, K_s,ϕ,tr° have been calculated from the experimental data. The viscosity data were examined by using the Jones-Dole equation and the viscosity A and B coefficients were evaluated. The results are discussed in terms of solute-solute and solute-solvent interactions in these solutions. The structure making/breaking ability of semicarbazide hydrochloride is examined using the sign of temperature derivative of B-coefficient, dB/dT.     

相变套管式储热系统放冷性能实验研究

搭建了套管式相变储热实验系统,分别填充不同质量分数膨胀石墨与正十五烷制备而成的复合相变材料,对系统进行重复充放冷循环实验。采用有效储热比E_st和储能效率ε来表征系统性能,研究了复合相变材料中换热增强对套管式潜热储能系统放冷性能的影响。结果表明：同Re数下,相变材料热导率为0.14 W·m^-1·K^-1（工况A）放冷结束时间为1770 s,相同Re条件下热导率提升至7.10 W·m^-1·K^-1（工况B）和11.60 W·m^-1·K^-1（工况C）的结束时间分别可缩短77.3%、78.9%;热导率的增加可显著提高系统有效储热比E_st和储能效率ε,热导率从0.14 W·m^-1·K^-1增加到11.60 W·m^-1·K^-1,E_st在层流区、过渡区和湍流区分别可提升33.3%、350.0%及129.6%,ε分别可提升26.8%、52.9%及14.6%;Re的增加使得工况A和工况B中E_st和ε呈现下降趋势,工况C中E_st在Re=4298出现峰值1.62。     

用定标粒子理论研究不同温度下2-甲基-2-丙醇与腈二元液相混合物的超额热力学参数和超音速度理论估值(英文)

Density, ρ, ultrasonic speed, u, and viscosity, η, of binary mixtures of 2-methyl-2-propanol (2M2P) with acetonitrile (AN), propionitrile (PN) and butyronitrile (BN) including those of pure liquids are measured over the entire composition range at temperatures 298.15, 303.15 and 308.15 K. From these experimental data, the excess available volume, E a V , excess free volume, E f V , excess isothermal compressibility, E T β , excess thermal expansion coefficient, E α , and excess internal pressure, E i π , are calculated. The variation of these properties with composition and temperature are discussed in terms of molecular interactions between unlike molecules of the mixtures. It is found that the values of E a V , E f V , E T β and E α are positive and those of E i π are negative for all the mixtures at each temperature studied, indicating the presence of weak interactions between 2M2P and AN/PN/BN molecules. The variations of E a V , E f V , E T β , E α and E i π values with composition indicate that the interactions in these mixtures follow the order: ANPNBN, i.e., the 2M2P-nitrile interaction decreases with the increase of alkyl chain length in these nitrile molecules. In addition, the theoretical ultrasonic velocity is calculated using the scaled particle theory and compared with the experimental values.     

正弦波纹挡板式沉降器内流动特性

采用VOF模型对正弦波纹式入口挡板的重力非均相沉降器内流场进行数值模拟研究。对比了正弦波纹挡板与平挡板的平均流场分布情况,分析了沉降器的轴向流速均一程度（λ₁）随时间演化特性,探究了λ₁和面积加权平均湍流强度（I_a）在沉降器内空间分布特性;引入流场均稳指标USC,研究了冲击间距（L_b/D）对USC的影响。结果表明：正弦波纹挡板作为入口构件可以有效降低返混。在0.84＜L_b/D＜2.17范围内,正弦波纹板沉降器内流场的均一程度整体高于平面挡板;随着L_b/D减小,平挡板沉降器内流场的λ₁基本不变,但正弦波纹挡板沉降器内流场的λ₁降低,且对I_a的影响不明显。对比平挡板,正弦波纹挡板可以有效降低轴向速度的梯度,使返混区面积减小,流场稳定性提高。随着L_b/D增加,USC值呈现多峰值趋势,L_b/D=2.17时正弦波纹板沉降器的USC取得极大值为14.68,较平挡板提高了93.67%。     

己基乙二胺-TFS型质子化离子液体与水分子间氢键相互作用的研究

通过前期实验研究,己基乙二胺-三氟甲磺酸([HHex][TFS])型质子化离子液体(protic ionic liquid,PIL)的极性部位具有两个氨基,亲水性较强,能够与水混溶90%(质量)(H₂O/ PIL)以上。因此利用密度泛函理论(density functional theory,DFT),在M06-2X/6-311G(d,p)的水平下,对 [HHex][TFS]与H₂O分子间形成的氢键作用进行了研究。设计了[HHex][TFS]分别与nH₂O (n = 1, 2, 6) 相结合的构型,并得到了较稳定构型共8种(S1~S8),计算了其分子间的相互作用能(ΔE ₀ ^BSSE)、分子振动频率(Δν)、二阶微扰能、电子密度(ρ _c)以及Laplace值(?² ρ _c)。分析结果显示,[HHex][TFS]与水分子间形成了较强的氢键,[HHex][TFS]与H₂O结合数量增加,构型中氢键相互作用增强,即S4(n=1)＜S6(n=2)＜S8(n=6)。     

Solvation of ions—XX. The ferrocene—ferricinium couple and its role in the estimation of free energies of transfer of single ions

The ferrocene-ferricinium electrode (Pt/Foc, Fic⁺) was investigated in water, acetonitrile, ethanol, DMSO and DMF using single scan cyclic voltammetry and phase sensitive ac polarography. The oxidation-reduction is pseudo-reversible in all five solvents with an electrochemical rate constant of approximately 10⁻² cm/s. In all solvents a slow irreversible chemical step involving the ferricinium cation follows electron transfer, so that slow cyclic voltammetry or polarography rather than potentiometry is preferred if ferrocene is to be used as a reference electrode in non-aqueous solvents.

The Strehlow assumption, ΔG_tr(Foc) = ΔG_tr(Fic⁺ gives very different free energies of transfer of single ions from non-aqueous solvents to water when compared with the TATB assumption that ΔG_tr(Ph₄As⁺) = ΔG_tr(Ph₄B⁻). This discrepancy is likely to be because ferricinium is only a moderately large cation, so that ΔG_tr(Fic⁺) is less positive than ΔG_tr(Foc) for transfer to water. The discrepancy is not because of abnormal electrochemical behavior of the Pt/Foc, Fic⁺ electrode in water or other solvents. Values of E° vs nhe, H₂O in a variety of solvents based on the TATB assumption are presented.     

含非对称Gemini离子液体二元混合体系的体积和黏度性质

在温度分别为293.15、303.15、313.15、323.15和333.15 K及大气压下,系统测定了非对称Gemini离子液体,1-(3-(三甲基铵)丙-1-基)-3-甲基咪唑双氰胺盐([N₁₁₁C₃MIM][N(CN)₂]₂),分别与乙腈(MeCN)、甲醇(MeOH)、乙醇(EtOH)所组成的二元混合物的密度和黏度。由密度和黏度值分别计算了二元混合物的超额摩尔体积(V_{\mathrm{m}}^{\mathrm{E}})和超额黏度(Δη)。V_{\mathrm{m}}^{\mathrm{E}}和Δη随组成的变化关系由Redlich-Kister方程进行了回归,得到方程参数。结果表明,V_{\mathrm{m}}^{\mathrm{E}}和Δη值与理想溶液间为负偏差,且存在最小值,说明二元体系中[N₁₁₁C₃MIM][N(CN)₂]₂和溶剂分子间相互作用力更强,同时与所研究分子的大小和形状的差异有关。同时,V_{\mathrm{m}}^{\mathrm{E}}和Δη随温度的变化关系表明,温度对研究混合物中的分子间相互作用有很大影响。     

五种新合成酯基取代的咪唑类离子液体电导率的测定与分析

离子液体的电导率性质反映了离子液体的导电性能,与溶剂中的电离度以及离子的溶剂化能力密切相关。为了研究本实验室合成的5种酯基取代的离子液体的电导率,用DDS307电导率仪测定1-乙酸甲酯基-3-甲基咪唑双三氟甲基磺酰亚胺([MIMCH₂COOCH₃]NTf₂)、1-乙酸乙酯基-3-甲基咪唑双三氟甲基磺酰亚胺([MIMCH₂COOCH₂CH₃]NTf₂)、1-乙酸正丙酯基-3-甲基咪唑双三氟甲基磺酰亚胺([MIMCH₂COOCH₂CH₂CH₃]NTf₂)、1-对甲基苯甲酸甲酯基-3-甲基咪唑双三氟甲基磺酰亚胺([MIMCH₂C₆H₄COOCH₃]NTf₂)和1-对甲基苯甲酸乙酯基-3-甲基咪唑双三氟甲基磺酰亚胺([MIMCH₂C₆H₄COOCH₂CH₃]NTf₂)在二甲基亚砜、甲醇、乙腈和乙酸乙酯中的电导率数据。结果表明,其他条件不变时,在一定浓度范围内,离子液体的电导率随着其浓度的增大而增大;在一定温度范围内,随着温度的升高,离子液体电导率增大;4种溶剂相比电导率从小到大顺序依次为乙酸乙酯、二甲基亚砜、甲醇、乙腈,反映了带酯基的5种离子液体与乙酸乙酯的相互作用。     

Gas-liquid chromatography study of poly(ethylene oxide)-solvent interactions: A molecular approach to solvation mechanisms

The heats of solution at infinite dilution, ΔH_s, of more than 40 solvents of widely different structure and polarity (from n-hexane to 2,2,2-trifluoroethanol) in liquid poly (ethylene oxide) PEO, derived from gas-liquid chromatography, were quantitatively analysed within the general framework of linear solvation energy relationships: −ΔH_s(kcal mol⁻¹) = 0.48 × 10²⁴P + 1.725μ + 4.29, R(26 solvents) = 0.9566. This linear multiparametric approach allows us to separate the contributions of dispersion-cavitation forces (probe polarizability P), of dipolar interactions (probe dipole moment μ) and of hydrogen bonding (H-bond donating power of the probe measured by the Taft empirical parameter). It affords reliable values for the heat of H-bonding formation between protic probes and PEO. The potential value of such a correlation analysis as a general strategy to quantify solute-polymer interactions in polar systems at a molecular level is emphasized.     

Polarographic studies of copper(II) in aqueous dimethylsulphoxide and aqueous acetone and free energy of transfer of copper(I) and copper(II) from water to dimethyl-sulphoxide-water mixtures

Polarographic studies of Cu(ClO₄)₂ in aqueous dimethylsulphoxide (DMSO) mixtures have identified compositions in which Cu(I) is stable. The half-wave potentials E_1/2, of Cu(II)/Cu(I) and Cu(I)/Cu(Hg) decrease in DMSO-water mixtures and values of free energies of transfer, ΔG_tr, of Cu(II) and Cu(I) from water to aqueous DMSO are reported. Similar measurement in aqueous acetone mixtures show that ΔG_tr Cu(II) increases upon addition of acetone.     

Intradiffusion,density and viscosity studies in binary liquid systems of acetylacetone + DMF/DMSO/benzene at 303.15 K and 333.15 K

Intradiffusion coefficients of acetylacetone (AcAc) and DMF/DMSO/benzene in binary systems over the entire concentration range at 303.15 K were determined by ¹H diffusion-order spectroscopy (DOSY) nuclear magnetic resonance (NMR)method based pulse field gradient (PFG). The densities and viscosities of the above three binary systemsat 303.15 Kwere also studied andemployed to calculate the excessmolar volumes (V^E) and deviations in viscosity (Δη). Besides, experiments were carried out at 333.15 K for the systemof AcAc+DMF. The solvent and temperature effect upon the difference in D between enol and keto tautomers, the tautomeric equilibrium and excess properties (V^E and Δη) were discussed as well. Isotherms of VE as a function of mole fraction of AcAc (x₁) show positive deviations in benzene but negative deviations in DMF and DMSO, whereas isotherms of Δη as a function of x₁ record positive deviations in DMF but negative in benzene and DMSO. V^E values show more negative and Δη values are less positive in the system of AcAc + DMF at 333.15 K compared to 303.15 K. The VE and Δη were fitted to a Redlich-Kister type equation and the measured results were interpreted concerning molecular interactions in the solutions.     

Microscopic and macroscopic atomization characteristics of a pressure-swirl atomizer,injecting a viscous fuel oil

Combustion of heavy fuels is one of the main sources of greenhouse gases, particulate emissions, ashes, NOxand SOx. Gasification is an advanced and environmentally friendly process that generates combustible and clean gas products such as hydrogen. Some entrained flow gasifiers operate with Heavy Fuel Oil(HFO) feedstock. In this application, HFO atomization is very important in determining the performance and efficiency of the gasifiers.The atomization characteristics of HFO(Mazut) discharging from a pressure-swirl atomizer(PSA) are studied for different pressures difference(Δp) and temperatures in the atmospheric ambient. The investigated parameters include atomizer mass flow rate( _m), discharge coefficient(CD), spray cone angle(θ), breakup length(Lb), the unstable wavelength of undulations on the liquid sheet(λs), global and local SMD(sauter mean diameter) and size distribution of droplets. The characteristics of Mazut sheet breakup are deduced from the shadowgraph technique. The experiments on Mazut film breakup were compared with the predictions obtained from the liquid film breakup model. Validity of the theory for predicting maximum unstable wavelength was investigated for HFO(as a highly viscous liquid). A modification on the formulation of maximum unstable wavelength was presented for HFO. SMD decreases by getting far from the atomizer. The measurement for SMD and θ were compared with the available correlations. The comparisons of the available correlations with the measurements of SMD andθ show a good agreement for Ballester and Varde correlations, respectively. The results show that the experimental sizing data could be presented by Rosin-Rammler distributions very well at different pressure difference and temperatures.     

Solubilization of Phenanthrene and Fluorene in Equimolar Binary Mixtures of Gemini/Conventional Surfactants

abstract This study deals with the enhanced solubilization of polycyclic aromatic hydrocarbons (PAHs) such as phenan-threne (PHE) and fluorene (FLR) in a pure cationic gemini (G6) and three conventiona...     

Lithium cycling efficiency and conductivity for high dielectric solvent/low viscosity solvent mixed systems

Lithium cycling efficiency on a lithium substrate (Li-on-Li cycling) and conductivity for various mixed solvent systems of high dielectric solvent (HDS) and low viscosity solvent (LVS) were examined for secondary lithium batteries. For the HDS, sulfolane, dimethylsulfoxide, γ-lactones, propylene carbonate (PC) and ethylene carbonate (EC) were used. For the LVS, tetrahydrofuran (THF), 2-methyl-THF, 1,2-dialkoxyethanes and 1,3-dioxolane (DOL) were used. For the solute, LiAsF₆, LiBF₄, LiCF₃CO₃ and LiClO₄ were used. Lithium cycling efficiencies newly measured on a Li substrate (E_a) for EC/LVS or PC/LVS were ca 5% or 15% higher than those previously obtained by simple cycling of Li on a Pt substrate, while the order of Li cycling efficiencies to LVS change is similar in both cases, except for EC/DOL or PC/DOL. The reasons seem to be that the Li-on-Li cycling minimizes the influence of electrochemical Li/Pt alloying and partial solvent oxidation during the cycle on Li cycling efficiency. The E_a values in HDS/LVS mixed systems incorporating LiAsF₆ or LiClO₄ tended to increase with a decrease in the reactivity to Li, of not only LVS but also HDS. EC/THF systems incorporating LiAsF₆ or LiClO₄ showed high E_a values of ca 95% even by Li-on-Li cycling, the value being higher than those (ca 92%) for LiBF₄ or LiCF₃SO₃ systems. In addition, for all the HDS/LVS mixed systems examined in this work, conductivities were higher than those for HDS or LVS single solvent systems. In regard to both conductivity and Li cycling efficiency, HDS/LVS mixed systems are considered to be effective in various lithium battery applications.     

酯基功能性离子液体性质及其在空气采样中的应用

合成了两种新型酯基功能性离子液体1-乙酸甲酯基-3-甲基咪唑双三氟甲基磺酰亚胺([CH₂COOCH₃MIM]NTf₂)和1-对甲基苯甲酸甲酯基-3-甲基咪唑双三氟甲基磺酰亚胺([CH₂C₆H₄COOCH₃MIM]NTf₂),研究了化合物的热稳定性,在各种溶剂中的溶解性以及在有机溶剂乙腈、DMSO、甲醇和乙酸乙酯中的电导率,同时比较了其与常用的富集材料Tenax的富集效果。结果表明：该类离子液体在300℃以下基本没有失重,热稳定性较好; 能与大多数有机溶剂互溶,溶解性随着溶剂极性的增加而增大;离子液体的电导率随着浓度和温度的升高而升高,且在不同有机溶剂中电导率相差较大,其顺序为κ(乙腈作溶剂)>κ(甲醇作溶剂)>κ(DMSO作溶剂)>κ(乙酸乙酯作溶剂);离子液体[CH₂COOCH₃MIM]NTf₂对酯类物质的富集效果优于Tenax。     

Solvent-, ion- and pH-specific swelling of poly(2-acrylamido-2-methylpropane sulfonic acid) superabsorbing gels

Homopolymer hydrogel of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and its nanocomposite counterpart were prepared to study their swelling properties. The hydrogels showed ability to absorb and retain electrolytes as well as binary mixtures of water and organic solvents (i.e., methanol, ethanol, acetone, ethylene glycol (EG), polyethylene glycol, N-methyl-2-pyrrolidone (NMP), and dimethylsulfoxide (DMSO). The nanocomposite gel exhibited lower swelling in all solvent compositions in comparison with non-composite gel. Unlike conventional acrylic acid-based hydrogels, the poly(AMPS) gels showed superabsorbing capacity in pure ethanol, methanol, EG, DMSO and NMP. Meanwhile, swelling capacity of poly(AMPS) hydrogel in DMSO-water mixtures was surprisingly found to be even higher than that in water. This extraordinary superswelling behavior was explained based on the interactions involved in solvation as well as the solubility parameters. The gels showed pH-independent superabsorbency in a wide range of pH (3–11). Saline-induced swelling transitions were also investigated and the ionic interactions were confirmed by FTIR spectroscopy.     

ε-CL-20在二元混合溶剂中晶体形貌的分子动力学模拟

利用分子动力学模拟的方法探究了乙酸乙酯与二溴甲烷组成的二元溶剂在298.15 K,1 atm下对ε-CL-20晶体形貌的影响。通过修正附着能模型(MAE)模型探究了溶剂-晶体相互作用,用分子动力学模拟预测了不同组成的乙酸乙酯/二溴甲烷混合溶剂中ε-CL-20的晶体形貌并与实验获得ε-CL-20的晶体形貌进行了对比。结果表明,实验获得的晶体形貌与模拟结果一致,且晶面粗糙度越大,溶剂-晶体相互作用越强。此外,还通过均方位移(MSD)分析了溶剂分子在不同晶面的扩散系数,探究了溶剂扩散速率对不同晶面的影响,并利用径向分布函数(RDF)分析了溶剂分子与晶体分子间相互作用的组成。     

微波化学反应的无量纲准数动力学模型研究：以偶氮二异丁脒盐酸盐（AIBA）分解反应为例

微波辅助化学已成为备受关注的研究课题,但微波反应动力学模型缺乏系统的研究严重阻碍了微波在化学工业化上的应用,微波化学反应在化学工程化的放大设计及应用缺乏基础依据。以偶氮二异丁脒盐酸盐（AIBA）分解反应为例,通过选择合适的溶剂调整其复配比例,得到一系列具有不同沸点的混合溶剂作为反应介质,使反应在混合溶剂沸点下进行,以保证反应过程中微波的持续作用来研究微波反应动力学。从微波作用下动量传递、热量传递和质量传递的影响因素进行考虑,选择了对微波化学反应必须和充分的因素,包括微波功率密度 p、黏度 μ、密度ρ、反应物的浓度 C_A、温度 T、热导率 λ、损耗角正切δ 和微波辐射频率f。采用量纲分析方法,通过模型分析建立了微波分解反应动力学模型。通过大量的实验数据进行拟合,回归出特定反应的模型参数。该模型估算值与实验值的误差较小,相关性较高,具有一定的预测能力可解决微波反应过程放大的基础性问题,有望用于指导微波工业化生产。     

KBaB5O9的两步法制备及其过程动力学研究

本文利用溶液法制备了K₂Ba[B₄O₅(OH)₄]₂·8H₂O,并将其进行热处理制备得到了KBaB₅O₉,利用XRD、FT-IR、TG-DTA-DTG对样品进行了表征。分析研究了由K₂Ba[B₄O₅(OH)₄]₂·8H₂O热处理制备KBaB₅O₉过程中的物相变化过程,其物相变化经历脱结晶水、脱羟基、重结晶、再分解、熔融再结晶5个阶段,其中结晶水的脱失分两步进行。运用Kissinger法、Flynn-Wall-Ozawa法、Šatava-Šesták法对K₂Ba[B₄O₅(OH)₄]₂·8H₂O结晶水第二步脱失过程的动力学参数进行了计算,可知K₂Ba[B₄O₅(OH)₄]₂·8H₂O结晶水第二步脱失过程的活化能E_s为151.94 kJ/mol,指前因子的对数值lg A_s为21.25 min^-1,机理函数G(α)=(1-2α/3)-(1-α)^2/3(其中α为转化率)。