水合邻苯二甲酸钠的合成、结构表征及热化学性质

选择邻苯二甲酸和氢氧化钠作为反应物,利用液相合成方法合成了水合邻苯二甲酸钠.利用X射线粉末衍射、化学与元素分析等方法表征了它的组成和结构.利用精密自动绝热热量计测定了该化合物在78～366K温区的摩尔热容.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(Cp,m)对温度(T)的多项式方程,用此方程进行数值积分得到此温度区间内每隔5K的舒平热容值和相对于298.15K时的热力学函数值.另外,依据Hess定律,通过设计合理的热化学循环,利用等温环境溶解-反应热量计分别测量了固相量热反应的反应物和产物在所选溶剂中的溶解焓,从而确定反应的反应焓为:ΔrHm=29.073±1.05kJ·mol-1.最后,利用反应的反应焓和其它反应物和产物已知的热力学数据计算出水合邻苯二甲酸钠的标准摩尔生成焓为:-1493.637±1.11kJ·mol-1.     

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78～370K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=329.50K.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(Cp,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100cm3、浓度为2mol·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?fHms=-(2069.30±0.74)kJ·mol-1.     

右旋布洛芬的低温热容

在80～370 K温度范围内, 用精密自动绝热量热计准确测量了右旋布洛芬的摩尔热容.其固态右旋布洛芬测量值对折和温度X[X=f(T)]的拟和方程为:Cp,m(S)=－39.483X4－66.649X3＋95.196X2＋210.84X＋172.98;相应的液态的拟和方程为 :Cp,m(L)=7.191X3＋4.2774X2＋56.365X＋498.5.并计算得到右旋布洛芬相对于室温(298.15 K)的摩尔焓和摩尔熵.右旋布洛芬的熔点为(324.15±0.02) K.基于摩尔热容的测量,还可获得右旋布洛芬的纯度为99.44％.并对右旋布洛芬和消旋布洛芬的热容进行了对比研究.     

邻苯二甲酸氢铵NH4(C8H5O4)(s)的低温热容和热化学研究

选择分析纯邻苯二甲酸和浓氨水为反应物,合成了邻苯二甲酸氢铵.利用元素分析、FTIR和X-射线粉末衍射技术表征了它的组成和结构.用精密自动绝热热量计测定了它在78～400 K温区的摩尔热容,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(Cp,m)随折合温度(X)变化的多项式方程,利用此方程计算出该温区内每隔5 K的舒平热容值和相对于298.15K的各种热力学函数值.另外,依据Hess定律,通过设计合理的热化学循环,利用等温环境溶解-反应热量计分别测定所设计反应的反应物和产物在所选溶剂中的溶解焓,得到该反应的反应焓为△rHθm=(1.787±0.514)kJ·mol-1.最后,利用此反应焓和反应中其他物质的热力学数据计算出邻苯二甲酸氢铵的标准摩尔生成焓为:△fHθm[NH4(C8H5O4),s]=-(912.953±0.628)kJ·mol-1.     

四硼酸锂水溶液体系的热容及离子相互作用

采用Setaram BT 2.15微量热仪测定了Li₂B₄O₇-H₂O体系(Li₂B₄O₇的浓度为0.00415~0.4208 mol/kg)在298.15, 308.15和323.15 K下的热容, 分别计算了不同温度和浓度下的表观摩尔热容, 并获得了不同温度下表观摩尔热容与浓度的关系式. 基于Li₂B₄O₇-H₂O体系的热容测定结果, 应用Pitzer电解质溶液离子相互作用表观摩尔热容模型, 拟合获得了四硼酸锂在不同温度下的Pitzer单盐参数.     

70～580 K小样品全自动精密绝热量热装置的建立--α-Al2O3的摩尔热容

建立了样品池容积为 7.4cm3 ,可在 70～ 5 80K温区工作的小样品量自动绝热量热计 .量热计设置有两层绝热屏 ,三层辐射屏及辅助控温套 ,以保证高温下量热系统良好的绝热条件 .样品池主体用紫铜制作 ,带有装卸管的容器上盖用黄铜制作 ,紫铜压帽盖与装卸管用螺纹连接铅锡合金垫片密封 ,保证样品池在整个实验温区保持高真空密封不泄漏 .量热计所有导线采用W30 11有机硅耐高温漆绝缘和固定 ,使量热计电测系统在高温下具有良好的稳定性 .所有量热测试数据 ,包括电能和温度的测量 ,全部由计算机按预定程序自动采集和处理 .测量量热标准物质α Al2 O3 的摩尔热容 ,检验了所建量热装置的可靠性 .α Al2 O3 的摩尔热容实验值与舒平值的标准偏差为± 0 .2 8%,与美国标准局数据比较 ,相对偏差在± 0 .4%以内     

β-FeOOH纳米流体的制备及其热容的绝热量热法研究

本文介绍了用FeCl3•6H2O和尿素为反应物,在不添加表面活性剂等添加剂的条件下,制备纳米流体（纳米颗粒悬浮液）的新方法。通过XRD和TEM表征技术,表明得到的固体样品是纺锤形的纳米β–FeOOH颗粒。由于反应体系中含有NH3分子,其中在N原子和Fe原子之间可能存在弱的相互作用,因此,可以获得稳定的β–FeOOH纳米流体。该体系超额热容的研究也支持这一观点。应用绝热量热仪测量了制备的固体β–FeOOH颗粒和其纳米流体在不同温度下的摩尔热容。建立了摩尔热容与温度的函数关系。由此可获得所研究样品的焓、熵等热力学函数相对于298 .15 K的改变量。     

配合物Zn(His)SO4·H2O(s)的低温热容和热力学性质

通过精密自动绝热热量计测定了配合物Zn(His)SO4*H2O(s)在78～390K温区的摩尔热容,由热容曲线得到其起始脱水温度328.90K;用最小二乘法拟合得到摩尔热容(Cp,m)对温度(T)的多项式方程,并在此基础上计算了它的各种热力学函数.此外,研究了其在惰性气氛下的热分解过程.     

重铬酸钾晶体低温热容及热力学性质的研究

用精密自动绝热量热计测定了重铬酸钾晶体在100～390 K温区内的摩尔热容.实验结果表明在研究温度区间内重铬酸钾无相变和其它热反常现象发生,但其热容在不同的温度范围表现出不同的变化趋势.在100 K≤ T ≤ 275 K和350 K≤ T ≤390 K区间内,其热容随温度的升高明显增大,在275 K≤ T ≤350 K区间,其热容约为定值.将重铬酸钾摩尔热容实验值Cp,m(J•K－1•mol－1)拟合成温度T的多项式方程,在100 K≤ T ≤275 K,为Cp,m=0.0050T2－1.0320T＋125.22； 275 K≤ T ≤ 350 K,为Cp,m=209.37； 350 K≤ T ≤390 K,为Cp,m= 0.0266T2－18.823T＋3542.3.根据热力学函数关系式,从热容值计算出了298.15 K～ 400 K温区范围内每隔5 K的热力学函数值.     

纳米铁的低温热容和热力学性质研究

用扫描电子显微镜(SEM)测定了纳米铁试样的粒径, SEM结果表明Fe试样平均粒径d为25 nm. 在84～350 K温区, 用精密低温绝热量热计测定了该纳米铁试样的等压摩尔热容, 拟合出其等压摩尔热容与热力学温度的函数关系式: Cp=36.831+14.772x−5.4968x2−0.7099x3−1.3188x4, 其中x=(T−234)/156. 根据热容与热力学函数关系, 计算了以298.15 K为基准的纳米Fe(d=25 nm)热力学函数, 并与文献报导的粗晶Fe及粒径87 nm Fe的热容进行了比较, 从能量角度分析了不同粒径Fe热容曲线差别产生的原因.     

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 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.     

1，1－二氨基2，2－二硝基乙烯（DADE）的热化学性质、热行为和热分解机理

The constant-volume combustion energy, △cU （DADE, s, 298.15 K）, the thermal behavior, and kinetics and mechanism of the exothermic decomposition reaction of 1,1-diamino-2,2-dinitroethylene （DADE） have been investigated by a precise rotating bomb calorimeter, TG-DTG, DSC, rapid-scan fourier transform infrared （RSFT-IR） spectroscopy and T-jump/FTIR, respectively. The value of △cHm （DADE, s, 298.15 K） was determined as （-8518.09±4.59） j·g^-1. Its standard enthalpy of combustion, △cU （DADE, s, 298.15 K）, and standard enthalpy of formation, △fHm （DADE, s, 298.15 K） were calculated to be （-1254.00±0.68） and （- 103.98±0.73） kJ·mol^-1, respectively The kinetic parameters （the apparent activation energy Ea and pre-exponential factor A） of the first exothermic decomposition reaction in a temperature-programmed mode obtained by Kissinger＇s method and Ozawa＇s method, were Ek=344.35 kJ·mol^-1, AR= 1034.50 S^-1 and Eo=335.32 kJ·mol^-1, respectively. The critical temperatures of thermal explosion of DADE were 206.98 and 207.08 ℃ by different methods. Information was obtained on its thermolysis detected by RSFT-IR and T-jump/FTIR.     

Preparation and Thermal Chemical Property of Complexes of Zinc Nitrate with Trytophan

IntroductionZincisanessentialtraceelementtothelife .Manydiseasesarousedfromadeficiencyofzincelementhavere ceivedconsiderableattention .L α Aminoacidsarebasicunitsofproteins .L α Trytophanisoneoftheeightspeciesofaminoacidsindispensableforlife ,whichhastobeab sorbedfromfoodbecauseitcannotbesynthesizedinthehumanbody .InviewofthecomplexesofL α trytophanandessentialelementsasaddictiveswidelyusedinsuchfieldsasfoodstuff,medicineandcosmetic ,1 3theyhaveabroadenprospectforapplications .Briefly ,ab…     

Thermochemical Properties and Non-isothermal Decomposition Reaction Kinetics of N-Guanylurea Dinitramide （GUDN）

Introduction N-Guanylurea dinitramide (GUDN) is a new ener-getic oxidizer with higher energy and lower sensitivity. Its crystal density is 1.755 g·cm-3. The detonation velocity is about 8210 m·s-1. Its specific impulse and pressure exponent are 213.1 s and 0.73, respectively. It has the potential for possible use as an energy ingredient of propellants and explosives from the point of view of the above-mentioned high performance. Its preparation,1 properties2 and hygroscopocity2 have been …     

Thermochemistry of the Ternary Complex Nd（Et2dtc）3（phen）

Introduction A series of lanthanide sulfide complexes have beenlargely used for ceramics and thin film materials1 andthese complexes could be prepared from the precursorswhich are the compounds containing lanthanide-sulfurbonds.2-4 For instance, the compounds synthesized with[(alkyl)2dtc]-, phen?H2O and lanthanide salts were usedas the volatile precursors for preparing lanthanide sul-fide, its friction properties in lubricant was investigatedin literature 5 and the preparation and propertie…     

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.     

Phase Chemistry Investigation on Cr(NO3)3‐Met‐H2O System

The solubility property of the ternary of Cr(NO₃)₃‐Met‐H₂O has been investigated in the whole concentration by the phase equilibrium method, and the phase diagram has been constructed. From the phase diagram, the congruently soluble complexes Cr(Met)(NO₃)₃·2H₂O (D) and Cr(Met)₂(NO₃)₃·2H₂O (E) have been prepared and characterized by chemical analysis, elemental analysis, IR and TG‐DTG. Their combustion energies have been determined by a RBC‐type I precision rotating‐bomb calorimeter, and their standard enthalpies of formation, Δf, Hθ_m, have been calculated as (‐1842.01 ± 2.13) kJ·mol^?1 and (‐1136.16 ± 4.45) kJ·mol^?1, respectively.