四氯合镉酸正十一烷铵的合成、晶体结构及低温热容

合成了四氯合镉酸正十一烷铵配合物(C₁₁H₂₃NH₃)₂CdCl₄(s)[简写: C₁₁Cd(s)]. 用X 射线单晶衍射技术、化学分析和元素分析确定其晶体结构和化学组成. 利用其晶体学数据计算出晶格能为: U_POT＝908.18 kJ·mol^-1. 利用精密自动绝热热量计测定了它在78～395 K 温区的低温热容, 结果表明, 该配合物在此温区出现两次连续的固-固相转变, 计算出两次相变的峰温、摩尔焓及摩尔熵分别为: T_trs,1＝(321.88±0.07) K, Δ_trsH_m,1＝(37.59±0.17) kJ·mol^-1, Δ_trsS_m,1＝(117.24±0.12) J·K^-1·mol^-1, T_trs,2＝(323.81±0.30) K, Δ_trsH_m,2＝(12.42±0.02) kJ·mol^-1 和Δ_trsS_m,2＝(38.36±0.09) J·K^-1·mol^-1. 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.     

Low-temperature Heat Capacities and Thermodynamic Properties of the Solid State Complexes(C2H10N2)MCl4(s)(M=Cu and Cd)

The tetrachlorocuprate(II) ethylenediammonium and tetrachlorocadmate(II) ethylenediammonium were synthesized. Chemical analysis, elemental analysis, and X‐ray crystallography were applied to characterize the compositions and crystal structures of the two complexes. The lattice potential energies and the radiuses of the anions of two complexes were calculated to be U_POT[(C₂H₁₀N₂)CuCl₄]=1810.19 kJ·mol^?1, U_POT[(C₂H₁₀N₂)CdCl₄]=1784.39 kJ·mol^?1, r[(CuCl₄)^2?]=0.308 nm, and r[(CdCl₄)^2?]=0.321 nm from the data of the crystal structure, respectively. Low‐temperature heat capacities of the two complexes were measured by a precision automatic adiabatic calorimeter with the small sample over the temperature range from 78 to 400 K, respectively. Two polynomial equations of heat capacities against the temperatures were fitted by least square method: C_p,_m[(C₂H₁₀N₂)CuCl₄, s] =213.553+118.578X?5.816X²+4.392X³+0.276X⁴ and C_p,_m[(C₂H₁₀N₂)CdCl₄, s] =190.927+98.501X?7.931X²+0.657X³+3.834X⁴, in which X= (T?239)/161. Based on the fitted polynomial equations, the smoothed heat capacities and thermodynamic functions of the two complexes relative to the standard reference temperature 298.15 K were calculated at intervals of 5 K.     

Crystal structures, lattice potential energies, and thermochemical properties of crystalline compounds (1-C(n)H(2n+1)NH3)2ZnCl4(s) (n = 8, 10, 12, and 13)

As part of our ongoing project involving the study of (1-C(n)H(2n+1)NH(3))(2)MCl(4)(s) (where M is a divalent metal ion and n = 8-18), we have synthesized the compounds (1-C(n)H(2n+1)NH(3))(2)ZnCl(4)(s) (n = 8, 10, 12, and 13), and the details of the structures are reported herein. All of the compounds were crystallized in the monoclinic form with the space group P2(1)/n for (1-C(8)H(17)NH(3))(2)ZnCl(4)(s), P21/c for (1-C(10)H(21)NH(3))(2)ZnCl(4)(s), P2(1)/c for (1-C(12)H(25)NH(3))(2)ZnCl(4)(s), and P2(1)/m for (1-C(13)H(27)NH(3))(2)ZnCl(4)(s). The lattice potential energies and ionic volumes of the cations and the common anion of the title compounds were obtained from crystallographic data. Molar enthalpies of dissolution of the four compounds at various molalities were measured at 298.15 K in the double-distilled water. According to Pitzer's theory, molar enthalpies of dissolution of the title compounds at infinite dilution were obtained. Finally, using the values of molar enthalpies of dissolution at infinite dilution (Δ(s)H(m)(∞)) and other auxiliary thermodynamic data, the enthalpy change of the dissociation of [ZnCl(4)](2-)(g) for the reaction [ZnCl(4)](2-)(g)→ Zn(2+)(g) + 4Cl(-)(g) was obtained, and then the hydration enthalpies of cations were calculated by designing a thermochemical cycle.     

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.     

Crystal Structure, Phase Transition, and Thermodynamic Properties of Bis-dodecylammonium Tetrachlorozincate (C12H25NH3)2ZnCl4(s)

The crystal structure and composition of (C₁₂H₂₅NH₃)₂ZnCl₄(s) were characterized by chemical and elemental analysis, X‐ray powder diffraction technique and X‐ray crystallography. The lattice energy of the title compound was calculated to be U_POT=888.82 kJ·mol^?1. Low temperature heat capacities of the title compound have been measured by a precision automated adiabatic calorimeter over the temperature range from 80 to 403 K. An obvious solid to solid phase transition occurred in the heat capacity curve, and the peak temperature, molar enthalpy and molar entropy of the phase transition of the compound were determined to be T_trs= (364.02±0.03) K, (_trsH_m= (77.567±0.341) kJ·mol^?1, and (_trsS_m= (213.77±1.17) J·K^?1·mol^?1, respectively. Experimental molar heat capacities before and after the phase transition were respectively fitted to two polynomial equations. The smoothed molar heat capacities and fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were calculated and tabulated at an interval of 5 K.     

The Mixing Enthalpy Interaction Coefficients of N,N′-Hexamethylenebisacetamide with l-Alanine and l-Serine in Aqueous Glucose Solutions at 298.15 K

The mixing enthalpies of N,N??-hexamethylenebisacetamide (HMBA) with l-alanine and l-serine in aqueous glucose solutions have been determined by using mixing-flow isothermal microcalorimetry along with their dilution enthalpies at the temperature of 298.15?K. These results can be used to obtain the heterotactic enthalpic interaction coefficients (h _xy , h _xxy , and h _xyy ) in the range of the glucose molality, (0 to 1.5) mol?kg^?1, according to the McMillan?CMayer theory. Combining our previous research results for glycine (see Liu et al. in J. Chem. Eng. Data 55, 5258?C5263, 2010), we find that the heterotactic enthalpic pairwise interaction coefficients h _xy between HMBA and the investigated amino acids in aqueous glucose solutions are all positive and reach maximum values at about 0.3 mol?kg^?1 glucose. In addition, the order for the value of h _xy of the three amino acids in pure water and aqueous solution of the same glucose molality is h _xy (l-alanine)>h _xy (l-serine)>h _xy (glycine). All variations of the heterotactic enthalpic pairwise interaction coefficients with the molalities of glucose in the quaternary systems are discussed in terms of solute?Csolute and solute?Csolvent interactions.     

生物热化学系统的微量热方法研究 Ⅱ.微量热法研究稻种萌发过程

用自行研制的微量热装置测定了稻种萌发的全热谱,由此得到了稻种萌发各产热阶段的热数据,并对不同谱线作了比较和讨论。     

The effect of catalyst concentration on the synthesis of single-wall carbon nanotubes

Single wall carbon nanotubes (SWNTs) were synthesized by electric arc discharge method with a mixture of nickel and yttrium as catalysts. The effect of the catalyst concentration on the synthesis of SWNTs was studied. Raman spectra of SWNTs have been recorded with excitation wavelengths from 476.5 to 1064 nm. The Raman peaks of the radial breathing modes (RBM) of SWNTs were assigned. The results indicate that the diameter distribution of SWNTs is in the range of 1.2-1.6 nm, and the SWNTs with diameter 1.43 nm are in the majority. The catalyst concentrations have large effect on the yield of SWNTs and little effect on the diameter distribution of SWNTs.     

Crystal Structure, Lattice Energy, and Standard Molar Enthalpy of Formation of the Complex (C11H18NO)2CuCl4(s)

The complex (C₁₁H₁₈NO)₂CuCl₄ (s), which may be a potential effective drug, was synthesized. X‐ray crystallography, elemental analysis, and chemical analysis were used to characterize the structure and composition of the complex. Lattice energy and ionic radius of the anion of the complex were derived from the crystal data of the title compound. In addition, a reasonable thermochemical cycle was designed, and standard molar enthalpies of dissolution for reactants and products of the synthesis reaction of the complex were measured by an isoperibol solution‐reaction calorimeter. The enthalpy change of the reaction was calculated to be Δ_rH^?_m=(2.69±0.02) kJ·mol^?1 from the data of the above standard molar enthalpies of dissolution. Finally, the standard molar enthalpy of formation of the title compound was determined to be Δ_rH^?_m[(C₁₁ H₁₈NO)₂CuCl₄, s]= ? (1822.96±6.80) kJ·mol^?1 in accordance with Hess law.     

Crystal Structure and Thermochemical Properties of 2-Pyrazine Carboxylate Lithium Monohydrate [Li(pyza)(H2O)]n(s)(pyza=2-Pyrazine Carboxylate)

A 2-pyrazine carboxylate lithium monohydrate [Li(pyza)(H₂O)]_n was synthesized in a mixed solution of redistilled water and anhydrous ethanol. X-Ray crystallography was applied to characterizing its crystal structure. Low temperature molar heat capacities were measured in a temperature range of from 78 K to 400 K with a precision automatic adiabatic calorimeter. Two polynomial equations of experimental molar heat capacity as a function of temperature were obtained by the least-squares method. The smoothed molar heat capacities and thermodynamic functions of the compound were calculated based on the fitted polynomial equations. In accordance with Hess's law, a reasonable thermochemical cycle was designed based on the preparation reaction of the target compound. The standard molar enthalpies of dissolution for the reactants and products of the designed thermochemical reaction were measured by an isoperibol solution-reaction calorimeter, and the enthalpy change of the reaction was obtained, i.e.,Δ_rH_m^θ=-(30.084±0.329) kJ/mol. The standard molar enthalpy of the formation of the target compound was determined as Δ_fH^θ_{m{[Li(pyza)(h2o)]n(s)}}=-(260.844±1.178) kJ/mol based on the enthalpy change of the reaction and standard molar enthalpies of the formation of other reactants and products. In addition, UV-Vis spectroscopy and the data of the refractive indexes were used to confirm whether the designed Hess thermochemical cycle was reasonable and reliable.