苯氧威 (C17H19NO4) 的热容和热力学性质

通过小样品精密自动绝热量热计测定了自己合成并提纯的苯氧威 (C₁₇H₁₉NO₄) 在79 ～ 360 K温区的低温摩尔热容。量热实验发现, 该化合物在320 ~ 330 K温区, 有一固 - 液熔化相变过程, 其熔化温度为（326.31±0.14）K, 摩尔熔化焓、摩尔熔化熵及化合物的纯度分别为：(26.98±0.04) kJ• mol^-1和（82.69 0.09）J•mol^-1•K^-1和 (99.53±0.01 )%。并计算出了80-360 K的热力学参数。用分步熔化法得到绝对纯化和物的熔点为326.60±0.06 K。用差示扫描量热 (DSC) 技术对该物质的固-液熔化过程作了进一步研究，结果与绝热量热法一致。     

4-羟甲基吡啶的热力学性质

用精密自动绝热量热计测定了4-羟甲基吡啶在79～380 K温区的摩尔热容. 实验结果表明, 该化合物在79～301 K温区无相变和热异常现象发生, 在301～331 K, 发生固-液相变, 其熔化温度、摩尔熔化焓及摩尔熔化熵分别确定为：325.12 K, 11.78 kJ•mol^-1 和36.23 J•K^-1•mol^-1. 根据热力学函数关系式, 从热容值计算了4-羟甲基吡啶在80～380 K温区以标准状态（298.15 K）为基准的热力学函数值. 用热重法(TG)对该化合物的热稳定性作进一步考察, 从TG曲线上观察到该化合物在490 K有最大的蒸发失重速率.     

稀土高氯酸盐-谷氨酸配合物[Pr2(L-α-Glu)2(ClO4)(H2O)7](ClO4)3•4H2O的低温热容和热化学研究

合成了一种稀土高氯酸盐-谷氨酸配合物. 经TG/DTG、化学和元素分析、FTIR及与相关文献对比, 确定其组成为[Pr₂(L-α-Glu)₂(ClO₄)(H₂O)₇](ClO₄)₃•4H₂O, 纯度为99.0%以上. 利用显微熔点仪分析发现其没有熔点. 在78～370 K温区, 用精密绝热量热仪测量其低温热容, 在285～306 K温区发现一明显吸热峰, 归结为固-固相变过程. 通过相变温区三次重复热容测量, 得到相变温度T_tr、相变焓Δ_trH_m和相变熵Δ_trS_m分别为(297.158±0.280) K, (12.338±0.016) kJ•mol^－1和(41.520±0.156) J•K^－1•mol^－1. 用最小二乘法将非相变温区的热容对温度进行拟合, 得到了热容随温度变化的两个多项式方程. 用此方程进行数值积分, 得到每隔5 K的舒平热容值和相对于273.15 K的热力学函数值. 根据TG/DTG结果, 推测了该配合物的热分解机理. 依据Hess定律, 选择1 mol•dm^－3盐酸为量热溶剂, 利用等温环境溶解-反应量热计, 测定了该配合物的标准摩尔生成焓为: Δ_fH_m⁰＝－(7223.1±2.4) kJ•mol^－1.     

稀土高氯酸盐-谷氨酸配合物[Pr2(L-α-Glu)2(ClO4)(H2O)7](ClO4)3•4H2O的低温热容和热化学研究

合成了一种稀土高氯酸盐-谷氨酸配合物. 经TG/DTG、化学和元素分析、FTIR及与相关文献对比, 确定其组成为[Pr₂(L-α-Glu)₂(ClO₄)(H₂O)₇](ClO₄)₃•4H₂O, 纯度为99.0%以上. 利用显微熔点仪分析发现其没有熔点. 在78～370 K温区, 用精密绝热量热仪测量其低温热容, 在285～306 K温区发现一明显吸热峰, 归结为固-固相变过程. 通过相变温区三次重复热容测量, 得到相变温度T_tr、相变焓Δ_trH_m和相变熵Δ_trS_m分别为(297.158±0.280) K, (12.338±0.016) kJ•mol^－1和(41.520±0.156) J•K^－1•mol^－1. 用最小二乘法将非相变温区的热容对温度进行拟合, 得到了热容随温度变化的两个多项式方程. 用此方程进行数值积分, 得到每隔5 K的舒平热容值和相对于273.15 K的热力学函数值. 根据TG/DTG结果, 推测了该配合物的热分解机理. 依据Hess定律, 选择1 mol•dm^－3盐酸为量热溶剂, 利用等温环境溶解-反应量热计, 测定了该配合物的标准摩尔生成焓为: Δ_fH_m⁰＝－(7223.1±2.4) kJ•mol^－1.     

烟酸的低温热容和标准摩尔生成焓

利用精密自动绝热热量计测量了分析纯烟酸在78～400 K温区的低温热容. 用最小二乘法将实验摩尔热容对温度进行拟合, 得到了热容随温度变化的多项式方程. 用此方程进行数值积分, 得到在此温区每隔5 K的舒平热容值和相对于298.15 K时的热力学函数值. 利用精密静止氧弹燃烧热量计测定了烟酸在298.15 K时的恒体积燃烧能为 Δ_cU＝ －(24528.3±16.1) J•g^－1. 依据物质燃烧焓定义计算出烟酸的标准摩尔燃烧焓为: Δ_cH_m^o＝－(3019.05±1.98) kJ•mol^－1. 最后, 依据Hess定律计算出烟酸的标准摩尔生成焓为: Δ_fH_m^o＝－(56.76±2.13) kJ•mol^－1.     

八水氢氧化钡Ba(OH)2×8H2O(s)的低温热容和热力学性质

八水氢氧化钡Ba(OH)₂×8H₂O(s)因相变潜热大使其作为胶囊化相变储能材料的应用已受到人们的广泛关注, 但是其热力学性质数据依然缺乏. 本文利用精密自动绝热量热计准确测定了八水氢氧化钡Ba(OH)₂×8H₂O(s)在78－370 K温区的低温热容. 在热容曲线上发现在345－356 K温区有一个明显的吸热峰. 通过分析发现, 这个峰对应着样品的熔化和第一次脱水的焓变之和. 用最小二乘法将78－345 K和356－369 K两个温区的摩尔热容实验值分别拟合成了热容对温度的多项式方程. 通过在温区298－370 K内的三次重复热容测量，得到了相转变所对应的峰温、焓变和熵变分别为：(355.007 ± 0.076) K, (73.506 ± 0.011) kJ×mol^-1 and (207.140 ± 0.074) J×K^-1×mol^-1. 通过两个热容多项式方程的数值积分计算出了这个化合物的舒平热容值和相对于298.15 K的热力学函数,(H_T - H_298.15K) 和 (S_T - S_298.15K). 另外，利用DSC和TG-DTG技术对这个化合物的热分解行为进行了进一步的研究. 从实验结果的分析知, 这个化合物的相转变的潜热之所以变得比正常化合物的大, 主要原因是它融化过程中伴随着7 H₂O 和脱出.     

配合物Zn(Met)SO4•H2O(s)的低温热容和标准摩尔生成焓

利用精密自动绝热热量计直接测定了配合物Zn(Met)SO₄•H₂O(s) 在78～370 K温区的摩尔热容. 通过热容曲线的解析得到该配合物的起始脱水温度为T₀＝329.50 K. 将该温区的摩尔热容实验值用最小二乘法拟合得到摩尔热容 (C_p,m)对温度(T)的多项式方程, 并且在此基础上计算出了它的舒平热容值和各种热力学函数值. 依据Hess定律, 通过设计热化学循环, 选择体积为100 cm³、浓度为2 mol•L^－1的盐酸作为量热溶剂, 利用等温环境溶解-反应热量计, 测定和推算出该配合物的标准摩尔生成焓为Δ_fH_m⁰＝－(2069.30±0.74) kJ•mol^－1.     

RE(C5H8NS2)3(C12H8N2)的标准摩尔生成焓

在无水乙醇中, 使低水合氯化稀土 (RE = Ho, Er, Tm, Yb, Lu) 与吡咯烷二硫代氨基甲酸铵 (APDC)和1,10-菲咯啉 (o–phen•H₂O) 反应, 制得其三元固态配合物. 用化学分析和元素分析确定它的组成为RE(C₅H₈NS₂)₃(C₁₂H₈N₂) (RE = Ho, Er, Tm, Yb, Lu). IR光谱说明RE³⁺ 分别与3个PDC^–的6个硫原子双齿配位, 同时与o–phen的2个氮原子双齿配位, 配位数为8. 用精密转动弹热量计测定了它们的恒容燃烧热△_cU分别为(-16788.46 ± 7.74), (-15434.53 ± 8.28), (-15287.80 ± 7.31), (-15200.50 ± 7.22)和(-15254.34 ± 6.61) kJ•mol^-1; 并计算了它们的标准摩尔燃烧焓△_cH_m^θ和标准摩尔生成焓△_fH_m^θ分别为( -16803.95 ± 7.74), (-15450.02 ± 8.28), (-15303.29 ± 9.28), (-15215.99 ± 7.22), (-15269.83 ± 6.61) kJ • mol^-1和 (-1115.42 ± 8.94), (-2477.80 ± 9.15), (-2619.95 ± 10.44), (-2670.17 ± 8.22), (-2650.06 ± 8.49) kJ•mol^-1.     

配位化合物Zn(Met)3(NO3)2·H2O(s)(Met=L-α-蛋氨酸)的低温热容及标准摩尔生成焓

利用精密绝热热量仪测定了化合物配合物Zn(Met)₃(NO₃)₂·H₂O (s) (Met=L-α-蛋氨酸)在78-371 K温区的摩尔热容. 通过热容曲线解析, 得到了该配合物的起始脱水温度为T_D=325.10 K. 将该温区的摩尔热容实验值用最小二乘法拟合得到了摩尔热容(C_p)对约化温度(T)的多项式方程, 由此计算得到了配合物的舒平热容值和热力学函数值. 基于设计的热化学循环, 选择100 mL of 2 mol·L^-1 HCl为量热溶剂, 利用等温环境溶解-反应热量计, 得到了298.15 K配合物的标准摩尔生成焓为Δ_fH_m⁰[Zn(Met)₃(NO₃)₂·H₂O(s),s]=-(1472.65±0.76) J·mol^-1.     

ApoCopC与汞（II）结合性质的光谱研究

在室温, pH 7.4, 10 mmol•L^-1Hepes（N-2-hydroxyethylpiperazine-N’-2-ethane-sulfonic acid）缓冲溶液条件下，通过紫外光谱法研究了apoCopC与汞（II）的结合性质。结果表明apoCopC的N，C- 端均可结合汞（II），且测得条件结合常数分别为K_n=(6.79 ± 1.12)´10⁶ mol^-1•L和K_c= (3.06±0.05)´10⁵ mol^-1•L。在pH 7.4，50 mmol·L^-1Hepes缓冲溶液条件下，用荧光光谱法研究了apoCopC的脲变性性质。结果表明汞（II）的结合对蛋白结构的维系具有稳定作用，并测得Hg_N²⁺-CoC-Hg_c²⁺ 和apoCopC的稳定吉布斯自由能（ΔG_D^H2O）分别为14.69±0.85 kJ•mol^-1和 16.66±0.55 kJ•mol^-1。     

水合烟酸铜Cu(Nic)2•H2O(s)(Nic＝烟酸)的合成、表征及热力学性质

近几十年来,烟酸盐类化合物或配合物由于优越的吸收率高和无毒副作用等特点使其在化妆品、药品和食品等领域作为营养添加剂具有重要应用前景。然而,这类化合物的基础热力学数据极其缺乏,从而限制了这类化合物的理论研究和应用开发的深入开展。为此,本论文利用室温固相合成方法和球磨技术合成了一种新化合物Cu(Nic)2•H2O(s),利用化学分析、元素分析、FTIR和X-射线粉末衍射技术表征了它的结构和组成,利用精密自动绝热热量计准确地测量了它在78-400 K温区的摩尔热容。在热容曲线的T ＝ 326-346 K温区观察到一个明显的固-液相变过程。利用相变温区三次重复实验热容的测量结果确定了此相变过程的峰温、相变焓和相变熵分别为：Tfus＝(341.290 ±0.873) K, DfusHm＝(13.582±0.012) kJ×mol-1, DfusSm＝(39.797±0.067) J×K-1×mol-1。通过最小二乘法将相变前和相变后的热容实验值分别拟合成了热容对温度的两个多项式方程。通过热容多项式方程的数值积分,得到了这个化合物的舒平热容值和相对于298.15 K的各种热力学函数值,并且将每隔5 K的热力学函数值列成了表格。     

2-氯-N,N-二甲基尼古丁酰胺的热容和热力学性质研究

Low-temperature heat capacities of 2-chloro-N,N-dimethylnicotinamide were precisely measured with a high-precision automated adiabatic calorimeter over the temperature range from 82 K to 380 K. The compound was observed to melt at （342.15±0.04） K. The molar enthalpy AfusionHm, and entropy of fusion, △fusionSm, as well as the chemical purity of the compound were determined to be （21387±7） J·mol^-1, （62.51±0.01） J·mol^-1·K^-1, （0.9946±0.0005） mass fraction, respectively. The extrapolated melting temperature for the pure compound obtained from fractional melting experiments was （342.25±0.024） K. The thermodynamic function data relative to the reference temperature 298.15 K were calculated based on the heat capacity measurements in the temperature range from 82 to 325 K. The thermal behavior of the compound was also investigated by different scanning calorimetry.     

Heat capacities and thermodynamic properties of 2-benzoylpyridine (C12H9NO)

The heat capacities of 2-benzoylpyridine were measured with an automated adiabatic calorimeter over the temperature range from 80 to 340 K. The melting point, molar enthalpy, Δ_fusH^m, and entropy, Δ_fusS^m, of fusion of this compound were determined to be 316.49±0.04 K, 20.91±0.03 kJ mol^–1 and 66.07±0.05 J mol^–1 K^–1, respectively. The purity of the compound was calculated to be 99.60 mol% by using the fractional melting technique. The thermodynamic functions (H_T–H_298.15) and (S_T–S_298.15) were calculated based on the heat capacity measurements in the temperature range of 80–340 K with an interval of 5 K. The thermal properties of the compound were further investigated by differential scanning calorimetry (DSC). From the DSC curve, the temperature corresponding to the maximum evaporation rate, the molar enthalpy and entropy of evaporation were determined to be 556.3±0.1 K, 51.3±0.2 kJ mol^–1 and 92.2±0.4 J K^–1 mol^–1, respectively, under the experimental conditions.     

4-硝基苯甲醇的低温热容和标准摩尔生成焓

用精密自动绝热量热计测定了4-硝基苯甲醇（4-NBA）在78 ~ 396 K温区的摩尔热容。其熔化温度、摩尔熔化焓及摩尔熔化熵分别为:(336.426 ± 0.088) K, (20.97 ± 0.13) kJ×mol-1 和 (57.24 ± 0.36) J×K-1×mol-1.根据热力学函数关系式,从热容值计算出了该物质在80 ~ 400 K温区的热力学函数值 [HT - H298.15 K] 和[ST - S298.15 K]. 用精密氧弹燃烧量热计测定了该物质在T＝298.15 K的恒容燃烧能和标准摩尔燃烧焓分别为 (C7H7NO3, s)＝- ( 3549.11 ± 1.47 ) kJ×mol-1 和 (C7H7NO3, s)＝- ( 3548.49 ± 1.47 ) kJ×mol-1. 利用标准摩尔燃烧焓和其他辅助热力学数据通过盖斯热化学循环, 计算出了该物质标准摩尔生成焓 (C7H7NO3, s)＝- (206.49 ± 2.52) kJ×mol-1 .     

苏糖酸钾的低温热溶及标准摩尔生成焓测定

以苏糖酸与碳酸氢钾反应制得苏糖酸钾K(C₄H₇O₅)·H₂O，通过红外光谱、热重、化学分析及元素分析等对其进行了表征。用精密自动绝热热量计测量了该化合物在78K-395K温区的摩尔热容。实验结果表明，该化合物存在明显的脱水转变，其脱水浓度、摩尔脱水焓以及摩尔脱水熵分别为：(380.524 ± 0.093) K，(19.655 ± 0.012) kJ/mol 和 (51.618 ± 0.051) J/（K·mol）。将78K-362K和382K-395K两个温区的实验热容值用最小二乘法拟合，得到了两个表示热容随温度变化的多项式方程。以RBC-II型恒容转动弹热量计测定目标化合物的恒容燃烧能为(-1749.71 ± 0.91) kJ/mol，计算得到其标准摩尔生成焓为(-1292.56 ± 1.06) kJ/mol。     

Thermochemistry on the Complex of Erbium Perchlorate with L-α-Glutamic Acid [Er2（L-Glu）2（H2O）6]（ClO4）4·6H2O（s）

A coordination compound of erbium perchlorate with L-α-glutamic acid, [Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）, was synthesized. By chemical analysis, elemental analysis, FTIR, TG/DTG, and comparison with relevant literatures, its chemical composition and structure were established. The mechanism of thermal decomposition of the complex was deduced on the basis of the TG/DTG analysis. Low-temperature heat capacities were measured by a precision automated adiabatic calorimeter from 78 to 318 K. An endothermic peak in the heat capacity curve was observed over the temperature region of 290-318 K, which was ascribed to a solid-to-solid phase transition. The temperature Ttrans, the enthalpy △transHm and the entropy △transSm of the phase transition for the compound were determined to be： （308.73±0.45） K, （10.49±0.05） kJ·mol^-1 and （33.9±0.2） J·K^-1·mol^-1. Polynomial equation of heat capacities as a function of the temperature in the region of 78-290 K was fitted by the least square method. Standard molar enthalpies of dissolution of the mixture [2ErCl3·6H2O（s）＋2L-Glu（s）＋6NaClO4·H2O（s）] and the mixture {[Er2（Glu）2（H2O）6]（ClO4）4·6H2O（s）＋6NaCl（s）} in 100 mL of 2 mol·dm^-3 HClO4 as calorimetric solvent, and {2HClO4（1）} in the solution A＇ at T=298.15 K were measured to be, △dHm,1=（31.552±0.026） kJ·mol^-1, △dHm,2 = （41.302±0.034） kJ·mol^-1, and △dHm,3 = （ 14.986 ± 0.064） kJ·mol^-1, respectively. In accordance with Hess law, the standard molar enthalpy of formation of the complex was determined as △fHm-=-（7551.0±2.4） kJ·mol^-1 by using an isoperibol solution-reaction calorimeter and designing a thermochemical cycle.     

Low-temperature heat capacity and standard molar enthalpy of formation of 9-fluorenemethanol (C14H12O)

Low-temperature heat capacities of the 9-fluorenemethanol (C₁₄H₁₂O) have been precisely measured with a small sample automatic adiabatic calorimeter over the temperature range between T=78 K and T=390 K. The solid–liquid phase transition of the compound has been observed to be T_fus=(376.567±0.012) K from the heat-capacity measurements. The molar enthalpy and entropy of the melting of the substance were determined to be Δ_fusH_m=(26.273±0.013) kJ · mol⁻¹ and Δ_fusS_m=(69.770±0.035) J · K⁻¹ · mol⁻¹. The experimental values of molar heat capacities in solid and liquid regions have been fitted to two polynomial equations by the least squares method. The constant-volume energy and standard molar enthalpy of combustion of the compound have been determined, Δ_cU(C₁₄H₁₂O, s)=−(7125.56 ± 4.62) kJ · mol⁻¹ and Δ_cH_m^∘(C₁₄H₁₂O, s)=−(7131.76 ± 4.62) kJ · mol⁻¹, by means of a homemade precision oxygen-bomb combustion calorimeter at T=(298.15±0.001) K. The standard molar enthalpy of formation of the compound has been derived, Δ_fH_m^∘(C₁₄H₁₂O,s)=−(92.36 ± 0.97) kJ · mol⁻¹, from the standard molar enthalpy of combustion of the compound in combination with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.     

Synthesis,Characterization and Thermodynamic Study of the Solid State Coordination Compound Ni(Nic)2·H2O(s)(Nic=Nicotinate)

A novel compound‐monohydrated nickel nicotinate was synthesized by the method of room temperature solid phase synthesis and ball grinder. FTIR, chemical and elemental analysis, TG/DTG, and X‐ray powder diffraction technique were applied to characterize the structure and composition of the coordination compound. Low‐temperature heat capacities of the solid coordination compound have been measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 386 K. A solid‐solid phase transition occurred in the temperature range of 328–358 K in the heat capacity curve, and the peak temperature, the molar enthalpy and molar entropy of the phase transition were determined to be T_trs=(356.759±0.697) K, Δ_trsH_m=(13.650±0.408) kJ· mol^?1, and Δ_trsS_m= (38.279±0.086) J·K^?1·mol^?1, respectively. The experimental values of the molar heat capacities in the temperature ranges of 78–328 K and 358–386 K were fitted to two polynomials, respectively. The polynomial fitted values of the molar heat capacities and fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were calculated and tabulated at the intervals of 5 K.     

Heat capacities and standard molar enthalpy of formation of pyrimethanil maleic salt and pyrimethanil fumaric salt

Novel anilino-pyrimidine fungicides, pyrimethanil maleic salt, and pyrimethanil fumaric salt (C₂₈H₃₀N₆O₄) were synthesized by a chemical reaction of pyrimethanil with maleic acid/fumaric acid. The low-temperature heat capacities of the two compounds were measured with an adiabatic calorimeter from 80 to 350 K. The heat capacities of pyrimethanil fumaric salt are bigger than that of pyrimethanil maleic salt in the measurement temperature range. The thermodynamic function data relative to 298.15 K were calculated based on the heat capacity-fitted curves. The melting points, the molar enthalpies (Δ_fus H _m), and entropies (Δ_fus S _m) of fusion of pyrimethanil maleic salt and pyrimethanil fumaric salt were determined from their DSC curves. The values indicate that pyrimethanil fumaric salt was more thermostable than pyrimethanil maleic salt. The constant-volume energies of combustion (Δ_c U _m ^o ) of pyrimethanil maleic salt and pyrimethanil fumaric salt were measured using an isoperibol oxygen bomb combustion calorimeter at T = (298.15 ± 0.001) K. From the Hess thermochemical cycle, the standard molar enthalpies of formation of the two compounds were derived and determined to be Δ_f H _m ^o (pyrimethanil maleic salt) = ?459.3 ± 4.9 kJ mol^?1 and Δ_f H _m ^o (pyrimethanil fumaric salt) = ?557.2 ± 4.8 kJ mol^?1, respectively. The results suggest that pyrimethanil fumaric salt is more chemically stable than pyrimethanil maleic salt.     

Low‐Temperature Heat Capacities and Standard Molar Enthalpy of Formation of Gramine (C11H14N2)

Low‐temperature heat capacities of gramine (C₁₁H₁₄N₂) were measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 401 K. A polynomial equation of heat capacities as a function of temperature was fitted by least squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at 5 K intervals. The constant‐volume energy of combustion of the compound at T=298.15 K was measured by a precision oxygen‐bomb combustion calorimeter as Δ_cU=−(35336.7±13.9) J·g⁻¹. The standard molar enthalpy of combustion of the compound was determined to be Δ_cH_m⁰=−(6163.2±2.4) kJ·mol⁻¹, according to the definition of combustion enthalpy. Finally, the standard molar enthalpy of formation of the compound was calculated to be Δ;_cH_m⁰=−(166.2±2.8) kJ·mol⁻¹ in accordance with Hess law.