合成羧乙基硫代丁二酸的热力学计算与分析

以3-巯基丙酸和马来酸为原料合成羧乙基硫代丁二酸,选用较准确的基团贡献法估算了反应体系中各组分的标准生成焓、标准生成自由能、标准熵和热容等热力学数据,推导出了反应焓、反应自由能和反应平衡常数随温度的变化关系式。通过对反应体系的热力学计算与分析,验证了该反应在热力学上的可行性。     

催化合成乙酸乙酯的热力学计算与分析

以无水乙醇和冰乙酸为原料,以对甲苯磺酸催化剂催化合成乙酸乙酯。采用基团贡献法估算了反应体系中乙酸、乙醇和乙酸乙酯在298．15K标准状态下的生成焓和标准熵,并且估算了这3种物质的热容随温度变化的关系式,计算了不同温度条件下反应的吉布斯自由能和标准平衡常数。通过对该反应体系的热力学计算与分析,验证了该反应在热力学上的可行性。     

Substituent Effects on Thermodynamic and Detonation Properties of Polynitrobenzenes

Density functional theory (DFT) calculations were performed for a series of polynitrobenzene derivatives. Some nitrobenzenes with amino groups attached were also investigated as a benchmark or as a precursor. Heats of formation (HOF) were evaluated. The isodesmic reactions used for the prediction of HOFs are of permutation type in terms of the substituents. The HOFs increase non‐additively with increasing number of nitro groups. The attachment of the amino groups to polynitrobenzenes dramatically decreases the HOF. The HOF of hexanitrobenzene (HNB) is 344.05 kJ mol⁻¹ at the B3LYP/6‐311+G** level. This value is much larger than that of the widely used 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB), which engenders HNB a large chemical energy of detonation. The strengths of the group interactions were analyzed according to the disproportionation energy. The nearest‐neighbor interactions in polynitrobenzenes are in the range of 27.20–55.90 kJ mol⁻¹. The energy barrier for the internal rotation of nitro group in nitrobenzene is 24.6 kJ mol⁻¹. However, the energy barrier for the internal rotation of 2‐position nitro group of 1,2,3‐trinitrobenzene is as large as 216.3 kJ mol⁻¹. The chemical energies of detonation for polynitrobenzenes with three or more nitro groups are over 6000 J g⁻¹. Pentanitroaniline and HNB have good performances in terms of detonation velocity and pressure.     

Effect of pressure on electric generation of PZT(30/70) and PZT(52/48) ceramics near phase transition pressure

Impact experiment of Pb(Zr_0.3Ti_0.7)O₃ and Pb(Zr_0.52Ti_0.48)O₃ ceramics were conducted by empolying shock reverberation techniques within 3-7 GPa and X-ray diffraction patterns of these materials have been measured at pressure up to 32 GPa with a diamond anvil cell and synchrotron radiation. To refine the crystal structure, Rietveld analysis was performed and bulk moduli were calculated using Birch-Murnaghan equation of state. We found a tetragonal phase transforming to a cubic phase in Pb(Zr_0.3Ti_0.7)O₃ and Pb(Zr_0.52Ti_0.48)O₃ ceramics at ∼7.4 GPa and ∼4 GPa respectively. For dynamic pressure experiment, a metal flyer accelerated by a gas gun facility impacts into PZT ceramics to investigate electric energy. As pressure increased, output voltage of Pb(Zr_0.3Ti_0.7)O₃ and Pb(Zr_0.52Ti_0.48)O₃ ceramics slightly increased below ∼7 GPa and ∼4 GPa. But the voltage increased near ∼7 GPa and ∼4 GPa. From the result, we could confirm that the phase transition influenced the considerable effect on the electrical power generation.     

碳酸二甲酯与邻苯二酚合成愈创木酚的热力学分析

利用Benson基团贡献法计算了碳酸二甲酯,邻苯二酚,愈创木酚的热力学数据标准摩尔生成焓ΔfHm^θ、标准熵Sm^θ和热容Cp,m。对碳酸二甲酯与邻苯二酚催化合成愈创木酚反应体系进行了热力学分析,通过对反应的焓变ΔrHm,自由能变ΔrGm和平衡常数K的计算表明该反应是吸热反应,其自由能变化为负值,有较大的热力学平衡常数,且反应温度对平衡常数K影响不大,该反应可在较低温度下进行,在保持高转换率的同时,也可减少副反应,其关键是研制开发低温活性高的催化剂。     

基团法估算临界参数的改进

在系统整理大量临界数据的基础上，提出了临界性质的新基因估算法及基团贡献值，Ｔｃ，ＰｃＩｃ的平均误差分别为０．７６、４．２５、２．３３％，此结果优于作为比较的Ｊｏｂａｃｋ法。此外，本法还可用于长链化合物。     

CaO含量对铝硼硅玻璃理化性能的影响与机理

以SiO₂、B₂O₃、Al₂O₃及碱土金属氧化物(MgO、CaO、SrO)为原料,利用高温熔融法制备无碱铝硼硅玻璃。研究不同CaO含量对无碱铝硼硅玻璃性能和结构影响作用规律。对玻璃进行了热综合分析(DSC)、耐化学稳定性和密度的性能测试,通过红外光谱(FTIR)和X射线光电子能谱(XPS)对玻璃试样进行网络结构分析。研究表明,玻璃的析晶区间面积随着CaO含量的增加,由3.7 J/g升高到15.03 J/g,[AlO₆]和[BO₄]的出现会导致玻璃网络结构疏松,玻璃的析晶倾向增强;玻璃的被酸侵蚀由3.6817 mg/cm₂增加到4.2609 mg/cm²,玻璃被碱侵蚀由1.4199 mg/cm²降低到1.0907 mg/cm²,碱侵蚀的过程中生成的一层硅酸钙薄膜阻碍了反应的进行;随着CaO含量的增加,玻璃中的非桥氧含量增加,会促使[AlO_4...     

Computer Aided Molecular Design of Solvents for Separation Processes

A new algorithm, the classified enumeration, is proposed to solve computer aided molecular design of solvents for separation processes. In this method, all groups are sorted into two parts, skeleton groups and function groups. The former can constitute alkane, arene (aromatic hydrocarbon) or cycloalkane, the latter are the remainder. The skeleton groups are combined to form molecules of alkane, arene or cycloalkane as the base by enumeration. The function groups replace the corresponding skeleton groups in the molecule of the base to build other molecules. The properties of all acquired molecules are calculated using group contribution methods to find the proper solvents for the separation process. When considering industrial practicability, the number of kinds of function groups are limited so that combinatorial explosion is avoided. Finally, several examples are presented to illustrate the availability of the method.     

灵芝中水溶性多糖测定方法的研究

着重对灵芝中水溶性多糖含量进行测定,利用乙醇溶液和铜试剂分离出灵芝中具有葡聚糖结构的水溶性多糖,用苯酚-硫酸法对其含量进行测定.该方法操作简单,重现性好,其回收率在95.4%-110.8%之间,结果令人满意.     

己内酰胺类离子液体的热力学性质(英文)

A series of caprolactam ionic liquids(ILs) containing incorporated halide anions were synthesized.Their physical properties,such as melting points,heats of fusion and heat capacities,were measured by differential scanning calorimeter(DSC).The results indicate that these ionic liquids exhibit proper melting points,high value of heats of fusion,and satisfying heat capacities which are suitable for thermal energy storage applications.     

Thermodynamic Properties of Caprolactam Ionic Liquids

A series of caprolactam ionic liquids (ILs) containing incorporated halide anions were synthesized. Their physical properties, such as melting points, heats of fusion and heat capacities, were measured by differential scanning calorimeter (DSC). The results indicate that these ionic liquids exhibit proper melting points, high value of heats of fusion, and satisfying heat capacities which are suitable for thermal energy storage applications.     

基团贡献法确定简化空穴理论状态方程的分子参数

本文对作者开发的简化空穴理论状态方程的纯物质参数做了基团贡献处理，得到了１４个基团参数，可以比较好地预测正构烷烃、异构烷烃、环烷烃、芳香烃及部分聚合物的热力学性质。     

第一性原理计算LiTaO_3光学性质与热力学性质

采用基于第一性原理的赝势平面波法系统计算了LiTaO3晶体的电子结构、光学性质和热力学性质。能带结构表明LiTaO3晶体重要的结构特征是Ta的6d轨道和O的2p轨道存在强的杂化作用。LiTaO3晶体极限折射率为2.4,在55 eV处有明显的光吸收、光反射和能量损失。室温时LiTaO3的恒容热容为24 J/mol·K,800 K时,徳拜温度达到873。     

EVA/LDPE/CB导电复合材料结构与性能的研究

以炭黑(CB)粒子为导电填料,乙烯-乙酸乙烯共聚物(EVA)和低密度聚乙烯(LDPE)为基体树脂,在HAAKE转矩流变仪中制备了EVA/LDPE/CB导电复合材料,研究了CB粒子的分散形态、共混体系相形态以及其与EVA/LDPE/CB共混体系导电性能的关系。通过DSC、DMA、SEM、溶剂溶解等方法考察了EVA/LDPE两相体系随着EVA含量的变化引起的相转变情况,同时也考察了CB在EVA/LDPE共混体系中的选择性分散情况。     

Thermodynamic Properties of Ionic Semiclathrate Hydrate Formed with Tetrabutylammonium Propionate

The phase equilibrium temperature and dissociation heat of tetrabutylammonium propionate (TBAPr) hydrate are reported. TBAPr hydrate is a type of ionic semiclathrate hydrates and also could potentially be used as thermal energy storage material. The temperature‐composition phase diagram of the TBAPr hydrate was determined in a defined range of mass fractions. Considering the dissociation heat of differential scanning calorimetry (DSC) measurements, multiple peaks of heat flow were observed in the TBAPr‐water system at the TBAPr mass fraction lower than 0.35, and there was a single peak at the mass fraction higher than 0.37.     

苯胺与甲醛合成4,4-二氨基二苯甲烷反应体系的热力学分析

苯胺与甲醛合成4,4-二氨基二苯甲烷（MDA）是一个复杂的反应体系。采用多种基团贡献法,计算了该反应体系涉及多种物质的基础热力学数据,以及主要反应的反应焓变、反应Gibbs自由能变以及各反应的平衡常数。结合热力学模拟计算,分析了体系温度、苯胺与甲醛的原料配比对该反应体系平衡转化过程的影响,并与实验数据进行对比验证。研究结果表明：由苯胺与甲醛合成MDA的反应为放热反应,升高体系温度有利于抑制副产物的生成,同时可获得较高的MDA收率。选取原料配比为3作为较优操作条件,可减少副产物的产生量,并降低后续产物分离能耗。     

Highly transparent polycrystalline Gd2O3 ceramic attained via ZrO2 stabilization effect

The transition from the cubic to monoclinic phase of Gd₂O₃ at high temperatures poses a significant challenge to the preparation of transparent Gd₂O₃ materials. In this work, we presented a straightforward yet effective method for fabricating transparent Gd₂O₃ ceramics. Via ZrO₂ stabilization effect for phase structure, highly transparent Gd₂O₃ ceramics were successfully fabricated by vacuum sintering at 1850 °C for 8 h. The effect of different Zr (0 ∼ 13 at%) concentrations on phase transition, grain growth, fracture mode and optical properties of Gd₂O₃ transparent ceramics was investigated. As the Zr content increases, the transition from the cubic (C) to monoclinic (M) phase is effectively suppressed, which is crucial for achieving Gd₂O₃ transparent ceramics. Moreover, the results indicate that the addition of ZrO₂ has a significant effect on grain growth by not only impeding the migration of grain boundaries but also affecting the phase composition. In addition, the 11 at% Zr-doped Gd₂O₃ ceramic exhibits the best optical properties, of which transmittance is about 76% at 850 nm and about 80% in the 2.5 µm ∼ 6 µm mid-infrared range. This work provides an illustrative example for the development of other ceramics with phase transition. The obtained Zr-doped Gd₂O₃ transparent ceramics with high optical quality are potential candidates for optical window, scintillator host and mid-infrared transmission materials.     

甲基异丙基酮制备3,4-二甲基吡唑的热力学计算与分析

采用Joback基团贡献法、Lydersen法、Riedel法、Ednister法、Rowlinson-Bondi对应状态法、Benson法估算了甲基异丙基酮制备二甲基吡唑反应体系相关物质的基本物性参数如常沸点、临界参数和偏心因子,基本热化学性质参数如气体热容、液体热容和蒸发潜热、气体标准摩尔熵、相变熵。利用键能法计算了气体的标准反应热,计算了实际反应条件下的反应热、吉布斯自由能及相关反应的化学平衡常数,并对反应体系的特点进行了分析,估算数据可为理论研究、工程设计与放大及生产提供参考。     

液晶聚氨酯的合成与性质

采用熔融酯交换法合成端基为羟基的液晶复合二酸二丁二醇酯（ＴＯＢＢ）,再与２,４－ＴＤＩ或ＭＤＩ反应;或用聚己二酸丁二醇酯二醇（ＰＢＡ）替代部分ＴＯＢＢ制备液晶聚氨酯。用差热扫描量热仪和偏光显微镜检测其液晶性。结果表明：ＰＢＡ替代部分ＴＯＢＢ后,降低聚氨酯相转变温度,中介相温度范围变窄。     

Hydration of Saccharides: Estimation of Reaction Properties and Equilibrium Conversion

Biomass holds great promise as a renewable source of hydrogen and thus as a zero‐emission, carbon‐neutral, and nearly inexhaustible energy resource. Thermodynamic analysis of biomass hydration is carried out to study the reaction properties considering a series of saccharides as a model. Equilibrium constants and composition are estimated in dependence on the saccharide chain length and temperature. The latter is also studied as a function of the reactant ratios and in the presence of nonreacting additives. Being highly endothermic, the reaction is thermodynamically favorable due to a high entropic contribution. Increase in the saccharide chain length affects the conversion only slightly, so the results for low‐molecular‐weight saccharides can be transferred to long‐chain ones.