Measurement and correlation of solubility of diosmin in four pure solvents and β-cyclodextrin solution at 298.15 K to 333.15 K

The aim of present study was to measure and correlate the solubility of poorly water-soluble flavonoid diosmin in water, ethanol, isopropyl alcohol (IPA), polyethylene glycol-400 (PEG-400) andβ-cyclodextrin (β-CD) aqueous solution (0.02 mol·L-1). The solubility of diosmin was measured using the shake flask method from (298.15 to 333.15) K at atmospheric pressure. The experimental solubilities of diosmin were regressed by the modified Apelblat model with a relative deviation in the range of 0.048%to 5.940%. The correlation coefficients were observed in the range of 0.9957 to 0.9995. The solubility of diosmin was found to be increased with temperature in all sample matrices investigated. The mole fraction solubility of diosmin was found to be higher inβ-CD aqueous solution and PEG-400 as compared to water, ethanol and IPA. Based on solubility data of present study, diosmin was considered as practical y insoluble in water, insoluble in ethanol&IPA and soluble in PEG-400 andβ-CD aqueous solution.     

Viscous behaviour of quaternary fluid solutions at 298.15 K

Assuming a quaternary fluid solution to be made up of six binaries, a statistical approach of Flory has been extended to develop the expression for dynamic viscosity of multicomponent system using the concept of absolute rate and free volume approaches of liquid state. A reasonable agreement has been achieved between theory and the experiment for n‐hexadecane + carbon tetrachloride + benzene + n‐hexane quaternary system at 298.15 over a wide range of composition. An attempt has also been made to explain the nature of the molecular interactions, involved in the light of excess thermodynamic functions whose sign and magnitude depend upon the chain length and size of the component liquids.     

Investigation of the Solubility of 3,4‐Diaminofurazan (DAF) and 3,3′‐Diamino‐4,4′‐azoxyfurazan (DAAF) at Temperatures Between 293.15 K and 313.15 K

The solubilities of 3,4‐diaminofurazan (DAF) and 3,3′‐diamino‐4,4′‐azoxyfurazan (DAAF) were investigated in water, dichloromethane, acetonitrile, ethyl acetate, methanol, and acetone between 293.15 K and 313.15 K. The solubility was determined by high‐pressure liquid chromatography with ultraviolet detection. The solubilities of DAF and DAAF are increased with the increasing of temperature in all solvents studied. The enthalpy of solution in each solvent was calculated according to van't Hoff Equation.     

293 K时YCl3在混合溶剂(DMF-H2O)中无限稀释摩尔电导率的测定

在293 K时测定了YCl3在混合溶剂(DMF-H2O)中的电导率,根据公式求得YCl3的摩尔电导率λ值,按Kohlraush经验公式作图,使用Origin软件进行线性拟合外推求得YCl3在混合溶剂(DMF-H2O)中的无限稀释摩尔电导率λ0=233.74 s·cm2·mol-1.     

Recent Developments of 19‐Nor‐1,25‐dihydroxyvitamin D3 Analogues

The vitamin D hormone, 1α,25‐dihydroxyvitamin D₃ [1,25‐(OH)₂D₃], exerts its hormonal effects predominantly on intestine, bone, and kidney, where it plays a crucial role in calcium and phosphorus homeostasis and bone mineralization. In addition to its classical actions, 1,25(OH)₂D₃ exerts pleiotropic effects in a wide variety of target tissues and cell types, often in an autocrine/paracrine fashion. These biological activities of 1,25(OH)₂D₃ have suggested a multitude of potential therapeutic applications for the vitamin D hormone in the treatment of hyperproliferative disorders (e.g. cancer and psoriasis), immune dysfunction (autoimmune diseases), and endocrine disorders (e.g. hyperparathyroidism). However, the calcemic effects induced by 1,25(OH)₂D₃—hypercalcemia, increased bone resorption, and soft tissue calcification—limit the use of the natural ligand in these clinical applications. Therefore, numerous 1,25(OH)₂D₃ analogues have been synthesized with the intent of producing therapeutic agents devoid of hypercalcemic and hyperphosphatemic side effects. To this aim, much attention has been focused on the development of 19‐nor‐vitamin D₃ derivatives that lack the ring‐A exocyclic methylene group (C19). In this review, the 19‐nor‐1,25(OH)₂D₃ analogues are classified according to modifications made at the A‐ring, the side chain, or both the A‐ring and side chain, as well as other positions. The biological activities of these 19‐nor‐1,25(OH)₂D₃ analogues are summarized and their structure–activity relationships and binding features with the vitamin D receptor (VDR) are discussed.     

NaCl在混合溶剂(DMF-H2O)中热力学性质的研究

应用钠离子选择性电极和Ag-AgCl电极组成可逆电池,通过测定电池的电动势,应用Debye-Hückel极限公式,求得不同温度下NaCl在混合溶剂(DMF-H2O)中的活度系数(γ±),计算了NaCl在混合溶剂(DMF-H2O)中的相对偏摩尔自由能,并据电解质溶液的溶剂化理论对NaCl溶液的活度系数及相对偏摩尔自由能的变化规律进行了初步的讨论。     

Measurement and correlation of liquid-liquid equilibrium for the ternary system (water + 1,2-dichloroethane + sulfolane) at 288.15, 298.15, and 308.15 K

Sulfolane is an important aprotic polar solvent. Liquid-liquid equilibrium(LLE) data for the ternary systems of water + 1,2-dichloroethane + sulfolane were measured at temperatures of 288.15, 298.15 and 308.15 K under the atmospheric pressure. The distribution coefficient and selectivity were determined from the measured LLE data, which showed that 1,2-dichloroethane is a suitable extractant for the recovery of sulfolane from its aqueous solution. The nonrandom two-liquid(NRTL) model and the uni...     

水溶液中丁醇在树脂上的吸附

水溶液中丁醇在树脂上的吸附杨立荣姚善泾朱自强（浙江大学化工系，杭州３１００２７）焦朝晖（浙江临海制药厂，临海３１７０００）关键词丁醇吸附吸附热力学１前言发酵产物在发酵液中浓度一般在２０～１００（ｇ／Ｌ）之间［１］，如丙酮／丁醇发酵液中总溶剂浓度为１８...     

Interactions of cobalt chloride with saccharose in aqueous solutions at 298.15 K

Mutual diffusion coefficients (interdiffusion coefficients) and molar electrical conductivities have been measured for cobalt chloride aqueous solutions in the absence and the presence of saccharose at different concentrations (from 0.01 to 0.3 mol dm⁻³) and 298.15 K. The diffusion coefficients were measured by using the conductimetric method. For these aqueous solutions, limiting molar conductivity values have been calculated. The value of λ⁰(Co²⁺) = 105.36 × 10⁻⁴ S m² mol⁻¹, obtained at 298.15 K in pure water solution, agrees well with that reported in the literature. The Nernst diffusion coefficient values derived from diffusion (1.301 × 10⁻⁹ m² s⁻¹) and from conductance (1.295 × 10⁻⁹ m² s⁻¹) are also in good agreement.The dependence of diffusion coefficients and electrical conductivity of CoCl₂ on the concentration of saccharose is discussed by considering the effect of the carbohydrate on the electrolyte dehydration, as well as on the ion-pairs and complexes (CoCl₂-saccharose and ions-saccharose) formation.     

Diffusion coefficients of aluminium chloride in aqueous solutions at 298.15, 303.15 and 315.15 K

Mutual diffusion coefficients (interdiffusion coefficients) have been determined for aluminium chloride in water at 298.15, 303.15 and 310.15 K at concentrations from 0.002 to 0.010 mol dm⁻³ together with molar conductivity values. The diffusion coefficients were obtained by using a conductimetric open-ended capillary cell. The experimental data were discussed on the basis of the Onsager-Fuoss model. The Nernst diffusion coefficients derived from diffusion 1.208 × 10⁻⁹ and 1.701 × 10⁻⁹ m² s⁻¹ and from conductance 1.238 × 10⁻⁹ and 1.692 × 10⁻⁹ m² s⁻¹, at two temperatures 298.15 and 310.15 K, respectively, agree well each other.     

Excess molar volumes for titanium butoxide contained binary and ternary systems at 298.15 K

The reported mixture properties of metal alkoxide are almost none in spite of their increasing usages. In this work, the excess molar volumes (V^E) were determined from measured densities for six binary systems of titanium butoxide (1) + ethanol (2), titanium butoxide (1) + 1-propanol (2), titanium butoxide (1) + 1-butanol (2), ethanol (1) + 1-propanol (2), 1-propanol (1) + 1-butanol (2) and ethanol (1) + 1-butanol (2) at 298.15 K. The experimental V^E were correlated with the Redlich–Kister polynomial. The partial excess molar volumes at infinite dilution were calculated with fitted binary parameters. Additionally the ternary V^E data at 298.15 K were also predicted for three systems of titanium butoxide (1) + ethanol (2) + 1-propanol (3), titanium butoxide (1) + ethanol (2) + 1-butanol (3) and titanium butoxide (1) + 1-propanol (2) + 1-butanol (3) by using the binary contribution model of Radojkovič with the binary Redlich–Kister parameters.     

Kinetic and Technological Analysis of Dimethyl Toluene‐2,4‐Dicarbamate Synthesis

The synthesis of dimethyl toluene‐2,4‐dicarbamate from 2,4‐toluene diamine and dimethyl carbonate is a complex reaction system. First, the reaction enthalpies, the Gibbs function changes, and the equilibrium constants of the reactions were calculated by several methods of group contribution. Secondly, the kinetics of the synthesis reaction over a zinc acetate catalyst was investigated in a batch autoclave. The kinetic model equations were established by parameter estimation based on experimental data, and the model met the requirements of the statistical test. The calculated results based on the model agreed well with the experimental data. According to the results of both thermodynamic calculation and kinetic analysis, the influence of some technological parameters, such as content of methanol in the feed and reaction temperature, on the synthesis reaction was discussed.     

Direct and Stereoselective Synthesis of Diversely Substituted 2,4‐trans‐(NH)‐Pyrrolidines by Copper(I)‐Catalyzed Radical Cyclization at Low Temperature

This work describes a successful copper(I)‐catalyzed radical cyclization of β‐haloethylallylamines bearing an unprotected NH‐group while retaining catalyst‐redox activity. The cyclization occurs regio‐ and diastereoselectively at 0 °C and furnishes diversely substituted 1,3‐trans‐(NH)‐pyrrolidines directly in high isolated yields. An involvement of the bulky copper complex in the cyclization step as the possible reason for the diastereoselectivity was proposed. Synthetic applications of the products in the preparation of useful 4‐chloro‐NH‐pyrrole in a single step, has also been demonstrated. A quick, mild and general method involving simple addition of trichloroacetic acid/dimethyl sulfoxide (CCl₃CO₂H‐DMSO) solution to readily accessible N‐allylaldimines and ketimines tolerating acid‐sensitive and highly deactivating substituents was developed to access the amine precursors.

     

308.15 K时N,N-二甲基甲酰胺中咪唑啉酮衍生物们的热动力学性质(英文)

Density,ultrasonic velocity and viscosity of imidazolinone derivatives are studied in dimethyl formamide(DMF) at 308.15 K.From the experimental data,various acoustical parameters,such as specific impedance Z,isentropic compressibilityκs,Rao's molar sound function Rm,van der Waals constant b,relaxation strength r,intermolecular free length Lf,internal pressureπ,solvation number Sn,relative association RA,etc.are evaluated,which helps in understanding the molecular interactions occurring in these solutions.     

化工热力学教改实践与体会

基于提高教学质量和教学效果,培养学生科学思维能力、分析解决问题能力和创新精神这一目的,我们针对学生的知识结构、学习能力和认知水平,尝试采用多种教学手段相结合:启发式教学、深化例题剖析、优化评价方法、组建课程学习小组和布置探究型作业等方法,收到了较佳的教学效果。     

Thermodynamic properties of 1‐ETHYL‐3‐methylimidazolium methanesulphonate with aromatic sulphur,nitrogen compounds at T = 298.15–323.15 K and P = 1 bar

This work investigates the ability of 1‐ethyl‐3‐methylimidazolium methanesulphate ([EMIM][MeSO₃]) as a green and tuneable solvent for denitrification and desulphurisation studies. Experimental density, surface tension and refractive index data have been measured for the following systems: [EMIM][MeSO₃] (1) + pyridine (2), [EMIM][MeSO₃] (1) + pyrrole (2), [EMIM][MeSO₃] (1) + quinoline (2), [EMIM][MeSO₃] (1) + indoline (2), [EMIM][MeSO₃] (1) + thiophene (2) and [EMIM][MeSO₃] (1) + water (2) over the entire mole fraction of [EMIM][MeSO₃] at T = 298.15–323.15 K and P = 1 bar. Further from experimental density, surface tension and refractive index, coefficient of thermal expansivity, excess molar volume, deviation of surface tension and refractive index deviation were also calculated. It was found that the heteroaromatic nitrogen/sulphur compounds are completely miscible in [EMIM][MeSO₃]. The surface tension values were found to increase while the refractive index decreases with increasing mole fraction of [EMIM][MeSO₃]. The experimental values for surface tension increased in the order: pyridine > thiophene > pyrrole > indoline > quinoline > water and for refractive index: pyridine > pyrrole > indoline > quinoline > thiophene > water. It was found that the composition of [EMIM][MeSO₃] has a greater influence than temperature in deciding the surface, optical and thermodynamic properties for similar molecular interaction such as IL–thiophene and IL–pyrrole than dissimilar molecules such as IL–water. Further quantum chemical‐based COSMO‐RS tool was used to estimate the activity coefficient at different composition. © 2012 Canadian Society for Chemical Engineering     

Thermal Behavior and Thermolysis Kinetics of the Explosive Trans‐1,4,5,8‐Tetranitro‐1,4,5,8‐Tetraazadecalin (TNAD)

Trans‐1,4,5,8‐Tetranitro‐1,4,5,8‐Tetraazadecalin (TNAD), a cyclic nitroamine, has been studied with regard to the kinetics and mechanism of thermal decomposition, using thermogravimetry (TG), IR spectroscopy, and pressure differential scanning calorimetry (PDSC). The IR spectra of TNAD have also been recorded, and the kinetics of thermolysis has been followed by non‐isothermal TG. The activation energy of the solid‐state process was determined by using the Flynn‐Wall‐Ozawa method. Compared with the activation energy obtained from the Ozawa method, the reaction mechanism of the exothermic process of TNAD was classified by the Coats‐Redfern method as a nucleation and nuclear growth (Avrami equation 1) chemical reaction (α=0.30–0.60) and a 2D diffusion (Valensi equation) chemical reaction (α=0.60–0.90). E_a and ln A were established to be 330.14 kJ mol⁻¹ and 29.93 (α=0.30–0.60) or 250.30 kJ mol⁻¹ and 21.62 (α=0.60–0.90).     

化工热力学双语教学模式改革与实践

基于作者多年化工热力学双语教学体会,对理工科高等教育课程引入双语教学的必要性、教师培养与选聘、因材施教的教学模式、学生双语教学适应性培养、教学内容的研究与协调及统学统考的教学管理等方面进行了分析与论述。     

Thermochemistry of Evaporation and Sublimation of 2,4,6‐Triazido‐1,3,5‐triazine

Saturated vapor pressure over cyanuric triazide melt was measured in the temperature range 393.15–453.15 K using glass membrane Bourdon pressure gauges. Measured evaporation heat and evaporation entropy are equal to 61.1±3.3 kJ mol^–1 and 111.3±6.1 J mol^–1 K^–1, respectively. According to DSC data, melting heat and melting entropy of cyanuric triazide are 22.2±1.3 kJ mol^–1 and 60.5±3.5 J mol^–1 K^–1, respectively. Based on the results obtained, the following dependence was found for the saturated vapor pressure over solid cyanuric triazide: P _s [Pa]=10^14.0 ⋅ exp[(–83300±3300)/RT ]. Concequently, sublimation heat and sublimation entropy of cyanuric triazide are equal to 83.3±3.3 kJ mol^–1 and 171.8±9.6 J mol^–1 K^–1, respectively. Saturated vapor pressure over solid cyanuric triazide at room temperature is equal to 0.25 Pa (1.9×10⁻³ Torr). It is concluded that high volatility of cyanuric triazide is caused by its low sublimation heat.