三元配合物Tb(Et2dtc)3(phen)的热化学性质

以铜试剂(NaEt2dtc•3H2O)和邻菲咯啉(o-phen•H2O) 与水合氯化铽(TbCl3•3.75H2O)在无水乙醇中制得了三元固态配合物.化学分析和元素分析确定其组成为Tb(Et2dtc)3(phen).IR光谱研究表明配合物中Tb3＋与NaEt2dtc中的硫原子双齿配位,同时与phen的氮原子双齿配位.用Calvet微热量计测定了298.15 K下液相生成反应的焓变ΔrHmθ(l),为(－21.819±0.055) kJ•mol－1,通过热化学循环计算了固相生成反应焓变ΔrHmθ(s),为(128.476±0.675) kJ•mol－1.改变反应温度,研究了液相生成反应的热动力学.用精密转动弹热量计测得配合物的恒容燃烧能ΔcU为(－17646.95±8.64) kJ•mol－1,经计算其标准燃烧焓ΔcHHmθ和标准生成焓ΔfHmθ分别为(－17666.16±8.64) kJ•mol－1和(－1084.04±9.49) 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。     

配合物的稳定性与配体酸碱强度之间的直线自由能关系 Ⅺ.铜(Ⅱ)—5—取代邻菲罗啉—α—氨基酸三元体系

在25.0±0.1C和0.1mol·dm~(-3)KNO_3存在下,用pH法测定了邻菲罗啉、5-硝基邻菲罗啉、5-氯邻菲罗啉、5-甲基邻菲罗啉为第一配体;脯氨酸、α-氨基异丁酸、异亮氨酸、缬氨酸、甘氨酸、丝氨酸为第二配体与铜(Ⅱ)形成三元配合物的稳定常数,结果表明三元配合物的稳定性与第一配体和第二配体的酸碱强度之间均存在直线自由能关系,应用反馈π键存在的程度讨论了配合物稳定性的变化趋势。     

RE(C5H8NS2)3(C12H8N2)(RE=La,Pr,Nd,Sm)的标准摩尔生成焓测定研究

在无水乙醇中,使低水合氯化稀土(RE=La, Pr, Nd, Sm)与吡咯烷二硫代氨基甲酸铵(APDC)和1,10-邻二氮菲(σ-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们的组成为RE (C₅H₈NS₂)₃(C₁₂H₈N₂) (RE= La, Pr, Nd, Sm).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σ-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Δ_cU,分别为-17776.94±7.72, -17810.41±7.93, -17762.71±7.91和-17482.42±9.35 kJ·mol^-1;并计算了它们的标准摩尔燃烧焓和标准摩尔生成焓,分别为-17792.43±7.72, -17825.90±7.93, -17778.20±7.91, -17497.91±9.35 kJ*mol^-1和-83.05±8.60, -64.70±9.40, -104.77±8.78, -388.70±10.13 kJ·mol^-1.估算出未研究的同类配合物Ce(C₅H₈NS₂)₃(C₁₂H₈N₂)和Pm(C₅H₈NS₂)₃(C₁₂H₈N₂)的和分别为-17815, -17660 kJ·mol^-1和-60, -217 kJ·mol^-1.     

铅-茜素紫-邻菲罗啉体系的极谱行为及其应用

用线性扫描示波极谱法研究了 Pb( ) -茜素紫 -邻菲罗啉体系的伏安行为 ,发现在含有 0 .1 mol/L KCl,p H 4.70的 HAc- Na Ac缓冲溶液中 Pb( ) -茜素紫 -邻菲罗啉体系产生一灵敏的极谱吸附波 ,其峰电位为 - 0 .56V( vs.SCE) ,峰电流与铅 ( )的浓度在 8× 1 0 - 8～ 2× 1 0 - 6 mol/L范围内呈线性关系 ,检出限为 5× 1 0 - 8mol/L;研究了电极反应机理 ,并用建立的方法测定了皮蛋中的铅含量。     

配合物的稳定性与配体酸碱强度之间的直线自由能关系 Ⅺ.铜(Ⅱ)-5-取代邻菲罗啉-α-氨基酸三元体系

在25.0±0.1C和0.1mol·dm^-3KNO₃存在下,用pH法测定了邻菲罗啉、5-硝基邻菲罗啉、5-氯邻菲罗啉、5-甲基邻菲罗啉为第一配体;脯氨酸、α-氨基异丁酸、异亮氨酸、缬氨酸、甘氨酸、丝氨酸为第二配体与铜(Ⅱ)形成三元配合物的稳定常数,结果表明三元配合物的稳定性与第一配体和第二配体的酸碱强度之间均存在直线自由能关系,应用反馈π键存在的程度讨论了配合物稳定性的变化趋势。     

三氯醋酸钕与8-羟基喹啉配合物的热化学研究

用溶解量热法 ,在自行研制的具有恒定温度环境的新型反应量热计中 ,测定了NdCl3·6H2 O(s)、CCl3COOH(s)和Nd(TCA) 3·3H2 O(s)在1mol/LHCl中的溶解焓。再根据盖斯定律设计了一个热化学循环 ,计算得到了六水合氯化钕与三氯醋酸反应的反应焓ΔrHmθ(2 98.15K) =2 0 1.688kJ/mol,并求出了Nd(TCA) 3·3H2 O(s)的标准生成焓ΔfHmθ[Nd(TCA) 3·3H2 O ,s ,2 98.15K ] =-3 0 5 3 .3kJ/mol。同时测定了Nd(TCA) 3·3H2 O(s) ,C9H7NO(s) ,Nd(TCA) (C9H6 NO) 2 (s)和CCl3COOH(s)在 4mol/LHCl、二甲亚砜和无水乙醇混合溶剂中的溶解焓 ,再根据盖斯定律设计了一个热化学循环 ,计算得到了三氯醋酸钕与 8 羟基喹啉反应的反应焓ΔrHmθ(2 98.15K) =-3 .2 2 6kJ/mol,并求出了Nd(TCA) (C9H6 NO) 2 (s)的标准生成焓ΔfHmθ[Nd(TCA) (C9H6 NO) 2 ,s ,2 98.15K] =-13 5 5 .6kJ/mol。     

三个溴代苯甲酸异构体的热力学研究

本文用升华量热法、落入量热法和差热分析方法,精密测定了邻位、间位和对位取代的三个溴代苯甲酸的升华焓、熔化焓及三相点温度,邻-溴、间-溴和对-溴苯甲酸在298.15K的标准升华焓分别为:(95.94±0.41),(99.20±0.18)和(103.08±0.59)kJmol~(-1)。三个化合物在相应升华温度下的饱和蒸气压也通过升华实验同时被测定出来。邻位、间位和对位异构体的三相点温度为:(422.37+0.01),(429.68±0.01)和(527.61±0.02)K;其熔化焓分别为(24.54±0.07),(21.27±0.09)和(28.70±0.08)kJmol~(-1)。 根据文献数据确定的苯环、酸基和溴功能团的能量贡献,计算出了对-溴代苯甲酸的升华焓,计算值与实验结果相符。比较三个异构体升华焓的差别,指出和解释了邻位异构体分子内氢键的存在。     

苯氧乙酸嘧霉胺盐的低温热容和热力学性质研究

用精密自动绝热量热计测定了苯氧乙酸嘧霉胺盐在81-380 K之间的低温热容. 结果表明, 该化合物在81-328 K之间无相变和热异常现象发生, 在328-354 K之间发生固-液熔化, 其熔化温度、摩尔熔化焓和摩尔熔化熵分别为(349.38±0.03) K, (34.279±10) kJ/mol和(98.13±0.05) J/（K·mol）. 根据热力学函数关系式计算出苯氧乙酸嘧霉胺盐在80-325 K之间以标准状态(298.15 K)为基准的热力学函数值.     

铈和硫代脯氨酸、水杨酸三元配合物的热化学性质

用七水合氯化铈与硫代脯氨酸(C4H7NO2S)和水杨酸(C7H6O3)合成了三元固体配合物[Ce(C7H5O3)2(C4H6NO2S)]·2H2O。根据盖斯定律设计一个热化学循环,用恒温环境的溶解―反应量热法研究得到合成反应的标准反应焓为263.12±0.95 kJ/mol,进而算出配合物298.15 K时的标准摩尔生成焓为-2785.7±3.2 kJ/mol。     

硝酸铕与二甲基甲酰胺配合物的研究

一、配合物合成及溶解性 配合物按文献[1]的方法合成,为微红色粉末,易溶于水、DMF、DMSO、乙醚、甲醇、乙醇、丙酮、氯仿,不溶于甲苯、二甲苯、CCl_4。 二、分析方法及实验条件 分析方法和实验条件同文献[1];燃烧能的测定仪器、实验条件,量热计当量计算和热交换校正,燃烧焓的换算和生成热的计算同文献[2]。 结果与讨论 一、配合物的性质 1.组成分析 元素分析实验值(％):Eu27.26,C20.07,H3.76,N14.85;计算值(％):Eu27.27,C19.40,H3.80,N15.08。 2.熔点及X-射线粉末衍射分析 配合物熔点为102.0～102.5℃;配合物及硝酸铕水合物     

The standard enthalpy of formation of fullerene chloride C<Subscript>60</Subscript>Cl<Subscript>30</Subscript>

A rotating-bomb calorimeter was used to measure the energy of combustion of crystalline fullerene chloride C₆₀Cl₃₀ · 0.09Cl₂, Δ_c U° = (?24474 ± 135 kJ/mol). The result was used to calculate the standard enthalpy of formation, Δ_f H° (C₆₀Cl₃₀, cr) = 135 ± 135 kJ/mol, and the C-Cl bond energy, 195 ± 5 kJ/mol. The C-X (X = F, F, Cl, and Br) bond energies in fullerene C₆₀ derivatives and other organic compounds are compared.     

The standard enthalpy of formation of 1,2,3,4-tetrachlorodibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxine

The energy of combustion of crystalline 1,2,3,4-tetrachlorodibenzo-p-dioxine (-5122.9 ± 7.4 kJ/mol) was measured using an isothermic-shell calorimeter with a rotating platinum plated bomb. The result was used to calculate the enthalpy of combustion (-5120.4 ± 7.4 kJ/mol) and formation (?267.8 ± 7.6 kJ/mol) for the crystalline state. The enthalpy of sublimation was measured using a Calvet microcalorimeter at 411.5 K (116.0 ± 2.6 kJ/mol); recalculation to T = 298.15 K gave 118.7 ± 2.6 kJ/mol. The enthalpy of formation of 1,2,3,4-tetrachlorodibenzo-p-dioxine in the gas state was calculated (?149.1 ± 8.0 kJ/mol)     

卟啉化合物的热化学研究——Ⅳ.精密转动氧弹燃烧热量计的建立与标定

A precision rotating-bomb combustion calorimeter in which thermistors were used as elements of temperature control and temperature measurement was constructed in our laboratory. The calorimeter was calibrated with benzoic acid of purity 99.999 percent. The energy equivalent of standard calorimeter system is 18.6376±0.0022 kJ.K~(-1). The precision of the experiment was 0.012% (shown in the form of 2s.d m) Detailed Washburn correction was made in microcomputer with programme designed by ourselves.     

Thermochemical studies on the thioproline

The combustion energy of thioproline was determined by the precision rotating-bomb calorimeter at 298.15 K to be Δ_c U= –2469.30±1.44 kJ mol^–1. From the results and other auxiliary quantities, the standard molar enthalpy of combustion and the standard molar enthalpy of formation of thioproline were calculated to be Δ_c H _m ^θC₄H₇NO₂S, (s), 298.15 K= –2469.92±1.44 kJ mol^–1 and Δ_f H _m ^θC₄H₇NO₂S, (s), 298.15K= –401.33±1.54 kJ mol^–1.     

Thermochemistry of copper complex of 6-benzylaminopurine

The copper(II) complex of 6-benzylaminopurine (6-BAP) has been prepared with dihydrated cupric chloride and 6-benzylaminopurine. Infrared spectrum and thermal stabilities of the solid complex have been discussed. The constant-volume combustion energy, Δ_c U, has been determined as −12566.92±6.44 kJ mol⁻¹ by a precise rotating-bomb calorimeter at 298.15 K. From the results and other auxiliary quantities, the standard molar enthalpy of combustion, Δ_c H _m ^θ, and the standard molar of formation of the complex, Δ_f H _m ^θ, were calculated as −12558.24±6.44 and −842.50±6.47 kJ mol⁻¹, respectively.     

The standard molar enthalpies of combustion and formation of 2-methylbenzothiazole, 2-methylbenzoxazole, and 2-methyl-2-thiazoline

A static-bomb combustion calorimeter and a rotating-bomb combustion calorimeter were used to determine the energies of combustion of 2-methylbenzothiazole, 2-methylbenzoxazole, and 2-methyl-2-thiazoline. The static- and rotating-bomb calorimeters were recently calibrated by the standard benzoic acid combustion runs and they were tested with adequate secondary combustion standards. The rotating-bomb calorimeter was tested using thianthrene and, in the present work, 1,2,4-triazole was used to test the static-bomb calorimeter. From the energies of combustion of the compounds under study, the liquid-phase standard molar enthalpies of formation were derived, at T = 298.15 K, as: (72.5 ± 1.5), (?50.7 ± 2.1), and (?88.5 ± 2.8) kJ mol^?1, respectively.     

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.     

烟酸钠Na(C6H4NO2)(s)的低温热容和热化学

选择分析纯烟酸和无水醋酸钠作为反应物, 用室温固相合成方法合成了无水烟酸钠. 利用FTIR和X射线粉末衍射等方法进行了表征, 利用化学分析和元素分析确定其组成为Na(C6H4NO2). 用精密自动绝热热量计测量其在78~400 K温度区间的低温热容. 研究结果表明, 该化合物在此温度区间无热异常现象发生. 用最小二乘法将实验摩尔热容对温度进行拟合, 得到热容随温度变化的多项式方程. 用此方程进行数值积分, 得到在此温度区间每隔5 K的舒平热容值和相对于298.15 K时的热力学函数值. 在此基础上, 通过设计合理的热化学循环, 选用1 mol/L NaOH溶液作为量热溶剂, 利用等温环境溶解-反应热量计分别测得固相反应的反应物和产物在所选溶剂中的溶解焓, 得到固相反应的反应焓. 最后, 计算出无水烟酸钠的标准摩尔生成焓为: ΔfHm0[Na(C6H4NO2), s]=-(548.96±1.11) kJ/mol.     

转动弹量热计的建立及对氯苯甲酸热值测定

元素有机物要达到完全的燃烧应当在转动弹量热计中进行,这种量热计与静止弹量热计比较有许多优点。首先,转动的结果起到了对弹液的搅拌作用,使弹内各部分溶液的浓度很快达到平衡。其次,促进了燃烧过程中某些副反应的进行,从而短期获得稳定的反应终态,使燃烧热测量的精度显著提高。