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Chemical Research in Chinese Universities 2008年第5期24卷 603-607页

作者： CHEN Jing-tao DI You-ying TAN Zhi-cheng CHEN San-ping GAO Sheng-li Department of Chemistry Shaanxi Educational College Xi＇an 710061 P. R. China College of Chemistry and Chemical Engineering Liaocheng University Liaocheng 252059 P. R. China Department of Chemistry Northwest University Xi＇an 710069 P. R. China

Low-temperature heat capacities of the solid compound Zn（C4H7O5）2（s） were measured in a temperature range from 78 to 374 K, with an automated adiabatic calorimeter. A solid-to-solid phase transition occurred in the temperature range of 295？322 K. The peak temperature, the enthalpy, and entropy of the phase transition were determined to be （316.269±1.039） K, （11.194±0.335） kJ？mol-1, and （35.391±0.654） J？K-1？mol-1, respectively. The experimental values of the molar heat capacities in the temperature regions of 78？295 K and 322？374 K were fitted to two polynomial equations of heat capacities（Cp,m） with reduced temperatures（X） and [X = f（T）], with the help of the least squares method, respectively. The smoothed molar heat capacities and thermodynamic functions of the compound, relative to that of the standard reference temperature 293.15 K, were calculated on the basis of the fitted polynomials and tabulated with an interval of 5 K. In addition, the possible mechanism of thermal decomposition of the compound was inferred by the result of TG-DTG analysis.

关键词： Zn(C4H7O5)2(s) adiabatic calorimetry Low-temperature heat capacity Solid-to-solid phase transition Thermodynamic property TG-DTG

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

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Chinese Journal of Chemistry 2007年第10期25卷 1423-1429页

作者：邸友莹张剑谭志诚 College of Chemistry and Chemical Engineering Liaocheng University Liaocheng Shandong 252059 China Therrnochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China

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.

关键词： [Er2(Glu)2(H2O)6](ClO4)4·6H2O(s) adiabatic calorimetry heat capacity isoperibol solution-reaction calorimetry standard molar enthalpy of formation

Low-temperature heat capacities and standard molar enthalpy of formation of pyridine-2,6-dicarboxylic acid

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Chinese Physics B 2010年第6期19卷 188-194页

作者：杨伟伟邸友莹孔玉霞谭志诚 College of Chemistry and Chemical Engineering Liaocheng University Thermochemistry Laboratory Dalian Institute of Chemical PhysicsChinese Academy of Sciences

This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of heat capacities as a function of temperature was fitted by the 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 intervals of 5 K. The constant-volume energy of combustion of the compound was determined by means of a precision rotating-bomb combustion calorimeter. The standard molar enthalpy of combustion of the compound was derived from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound was calculated from a combination of the datum of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.

关键词： pyridine-2,6-dicarboxylic acid adiabatic calorimetry low-temperature heat capacity standard molar enthalpy of formation

Crystal Structure and Thermodynamic Study of Ephedrine Hydrochloride C_(10)H_(16)NOCl(s)

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Chemical Research in Chinese Universities 2010年第2期26卷 304-308页

作者： YANG Wei-wei DI You-ying LI Jing KONG Yu-xia College of Chemistry and Chemical Engineering Liaocheng University Liaocheng 252059 P. R. China

The crystal structure of ephedrine hydrochloride was determined by means of X-ray crystallography. The crystal system of the compound is monoclinic, and the space group is P21. Unit cell parameters are a=0.7308（6） nm, b=0.6124（5） nm, and c= 1.2618（11） nm; β=90°, β= 102°, and γ =90°; Z=2. Low-temperature heat capacities of the title compound were measured with an improved precision automated adiabatic calorimeter over a temperature range from 77 K to 396 K. A polynomial equation of the heat capacities as a function of temperature in the temperature region was fitted by the least-squares. Based on the fitted polynomial equation, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at the intervals of 5 K.

关键词： Ephedrine hydrochloride C10H16NOCl(s) X-ray crystallography adiabatic calorimetry Low-temperature heat capacity Thermodynamic function

Low-temperature Heat Capacity and Standard Molar Enthalpy of Formation of Potassium L-Threonate Hydrate K（C4H7O5）·H2O

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Chinese Journal of Chemistry 2006年第2期24卷 187-192页

作者：魏青陈三平高胜利邸友莹谭志诚史启祯 Department of Chemistry Northwest University Xi'an Shaanxi 710069 China Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences DalianLiaoning 116023 China

The solid potassium L-threonate hydrate, K（C4H7O5）·H2O, was synthesized by the reaction of L-threonic acid with aqueous potassium hydrogen carbonate and characterized by means of chemical and elemental analyses, IR and TG-DTG. Low-temperature heat capacity of K（C4H7O5）·H2O has been precisely measured with a small sample precise automated adiabatic calorimeter over the temperature range from 78 to 395 K. An obvious process of the dehydration occurred in the temperature region of 364-382 K. The peak temperature of the dehydration of the compound has been observed to be （380.524±0.093） K by means of the heat capacity measurements. The molar enthalpy, △dHm, and molar entropy, △dSm, of the dehydration of K（C4H7O5）·H2O were calculated to be （19.655 ± 0.012） kJ/mol and （51.618 ± 0.051） J/（K·mol） by the analysis of the heat-capacity curve. The experimental molar heat capacities of the solid from 78 to 362 K and from 382 to 395 K have been respectively fitted to two polynomial equations of heat capacities against the reduced temperatures by least square method. The constant-volume energy of combustion of the compound, △cUm, has been determined to be （- 1749.71 ±0.91） kJ·mol^-1 by an RBC-Ⅱ precision rotary-bomb combustion calorimeter at 298.15 K. The standard molar enthalpy of formation of the compound, △fHm , has been calculated to be （- 1292.56± 1.06） kJ·mol^-1 from the combination of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities.

关键词： potassium L-threonate hydrate low-temperature heat capacity adiabatic calorimetry rotary-bomb combustion calorimetry standard molar enthalpy of formation

Heat Capacity and Enthalpy of Fusion of Crystalline Pyrimethanil Decylate(C_(22)H_(33)N_3O_2)

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Chemical Research in Chinese Universities 2005年第6期21卷 697-701页

作者： SUN Xiao-hong LIU Yuan-fa TAN Zhi-cheng WANG Mei-han JIA Ying-qi College of Chemical Engineering Chemical Research Institute Northwest University Xi＇an 710069 P. R. China Department of Chemistry Northwest University Xi＇an 710069 P. R. China Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 P. R. China

Low-temperature heat capacities of pyrimethanil decylate （ C22 H33 N3 O2 ） were precisely measured with an automated adiabatic calorimeter over the temperature range from 78 to 373 K. The sample was observed to melt at （311.04 ± 0.06） K. The molar enthalpy and entropy of fusion as well as the chemical purity of the compound were determined to be（45876± 12） J/mol, （147. 50 ±0. 05） J. mol^-1 · K^-1 and （99. 21 ±0. 03）% （mass fraction）, respectively. The extrapolated melting temperature for the absolutely pure compound obtained from fractional melting experiments is （311. 204±0. 035 ） K.

关键词： Pyrimethanil decylate Heat capacity adiabatic calorimetry DSC

Thermodynamic Study on the Azeotropic Mixture Composed of Ethanol and Toluene

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Chinese Journal of Chemistry 2005年第7期23卷 823-828页

作者：南照东谭志诚邢军 DepartmentofChemistry QufuNormalUniversityQufuShandong273165China//ThermochemistryLaboratoryDalianInstituteofChemicalPhysicsChineseAcademyofSciencesDalianLiaoning116023China DepartmentofChemistry QufuNormalUniversityQufuShandong273165China ThermochemistryLaboratory DalianInstituteofChemicalPhysicsChineseAcademyofSciencesDalianLiaoning116023China

The molar heat capacity of the azeotropic mixture composed of ethanol and toluene was measured by a high precision adiabatic calorimeter from 80 to 320 K. The glass transition and phase transitions of the azeotropic mixture were determined based on the heat capacity measurements. A glass transition at 103.350 K was found. A solid‐solid phase transition at 127.282 K, two solid‐liquid phase transitions at 153.612 and 160.584 K were observed, which correspond to the transition of metastable crystal to stable crystal of ethanol and the melting of ethanol and toluene, respectively. The thermodynamic functions and the excess ones of the mixture relative to the standard temperature 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to temperature.

关键词： azeotropic mixture ethanol toluene heat capacity excess thermodynamic function adiabatic calorimetry

Low-Temperature Heat Capacities and Thermodynamic Properties of Hydrated Nickel L-Threonate Ni（C4H7O5）2·2H2O（S）

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Chinese Journal of Chemistry 2007年第3期25卷 289-294页

作者：邱友莹谭志诚高胜利陈三平孙立贤 College of Chemistry and Chemical Engineering Liaocheng University Liaocheng Shandong 252059 China Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China Department of Chemistry Northwest University Xi'an Shaanxi 710069 China

Low-temperature heat capacities of the compound Ni（C4H7O5）2·2H2O（S） have been measured with an auto- mated adiabatic calorimeter. A thermal decomposition or dehydration occurred in 350--369 K. The temperature, the enthalpy and entropy of the dehydration were determined to be （368.141 ±0.095） K, （18.809±0.088） kJ·mol ^-1 and （51.093±0.239） J·K^-1·mol^-1 respertively. The experimental values of the molar heat capacities in the temperature regions of 78-350 and 368-390 K were fitted to two polynomial equations of heat capacities （Cp,m） with the reduced temperatures （X）, [X=f（T）], by a least squares method, respectively. The smoothed molar heat capacities and thermodynamic functions of the compound were calculated on the basis of the fitted polynomials. The smoothed values of the molar heat capacities and fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were tabulated with an interval of 5 K.

关键词： Ni(C4H7O5)2·2H2O(S) adiabatic calorimetry low-temperature heat capacity dehydration process,thermodynamic property

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

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Chinese Journal of Chemistry 2011年第11期29卷 2278-2284页

作者：陈经涛孔玉霞邸友莹杨伟伟谭志诚 Department of Chemistry and Chemical Engineering Shaanxi Institute of Education Xi＇an Shaanxi 710061 China College of Chemistry and Chemical Engineering Liaocheng University Liaocheng Shandong 252059 China Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China

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 △cU=-（35336.7±13.9） j·g^-1. The standard molar enthalpy of combustion of the compound was determined to be △cHm=-（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 △cHm=-（166.2±2.8） kJ·mol-1 in accordance with Hess law.

关键词： alkaloids adiabatic calorimetry low-temperature heat capacity oxygen-bomb combustion calorimetry standard molar enthalpy of formation thermodynamics

Measurements of the Heat Capacity of an Azeotropic Mixture of Water and n-Butanol from 78 to 320 K

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Chinese Journal of Chemistry 2005年第10期23卷 1297-1302页

作者：南照东谭志诚邢军 Department of Chemistry Qufu Normal University Qufu Shandong 273165 China Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China

Molar heat capacities of n-butanol and the azeotropic mixture in the binary system [water （x=0.716） plus n-butanol （x=0.284）] were measured with an adiabatic calorimeter in a temperature range from 78 to 320 K. The functions of the heat capacity with respect to thermodynamic temperature were estabhshed for the azeotropic mixture. A glass transition was observed at （111.9±1.2） K. The phase transitions took place at （179.26±0.77） and （269.69±0.14） K corresponding to the solid-hquid phase transitions of n-butanol and water, respectively. The phase-transition enthalpy and entropy of water were calculated. A thermodynamic function of excess molar heat capacity with respect to temperature was estabhshed, which took account of physical mixing, destructions of self-association and cross-association for n-butanol and water, respectively. The thermodynamic functions and the excess thermodynamic ones of the binary systems relative to 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity and the calculated excess heat capacity with respect to temperature.

关键词： adiabatic calorimetry heat capacity excess heat capacity azeotropic mixture water n-butanol