5-氨基间苯二甲酸钠和5-羟基间苯二甲酸钠的热力学性质

在水溶液中合成了5-氨基间苯二甲酸钠(1)和5-羟基间苯二甲酸钠(2)固态样品,元素分析和TG-DTG确定其组成符合C8H5O4NNa2·H2O(1)和C8H4O5Na2·H2O(2).用精密自动绝热热量计测定了它们在78～400K温区的低温热容,将实验值用最小二乘法拟合,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,得到该温区内每隔5K的舒平热容值和各种热力学函数值.用RD496-2000型微热量计测定了样品在298.15K时的标准摩尔溶解焓分别为ΔsolHmθ(1,s)=-44.552±0.164kJmol-1和θΔsolHm(2,s)=-36.055±0.154kJmol-1,计算了其水合阴离子标准摩尔生成焓分别为θΔfHm(C8H5O4N2-,aq)=-684.56±1.67kJmol-1和ΔfHmθ(C8H4O52-,aq)=-1263.43±2.13kJmol-1.用RBC-II型精密转动弹热量计测定了样品的恒容燃烧热分别为ΔcU(1,s)=-13382.14±5.28Jg-1和ΔcU(2,s)=-10339.15±4.15Jg-1,计算了它们的标准摩尔燃烧焓和标准摩尔生成焓分别为ΔcHmθ(1,s)=-3252.90±1.28kJmol-1和θΔcHm(2,s)=-2522.64±1.01kJmol-1,ΔfHmθ(1,s)=-1406.46±1.66kJmol-1,θΔfHm(2,s)=-1993.79±1.46kJmol-1.     

水合偏硼酸钾的热化学研究

Hydrated potassium monoborate(KBO₂·4/3H₂O) was obtained from an aqueous solution in a mole ratio of K₂O∶B₂O₃=2∶1 and characterized by powder X-ray diffraction(XRD)， infrared spectroscopy(FT-IR) and Raman spectroscopy. The enthalpy of solution of hydrated potassium monoborate， KBO₂·4/3H₂O， in approximately 1mol·dm^-3 aqueous hydrochloric acid was determined. Together with the previously determined enthalpies of so-lution of H₃BO₃ in approximately 1mol·dm^-3 HCl(aq) ，and of KCl in aqueous(hydrochloric acid+boric acid)， the standard molar enthalpy of formation of -(1411.11±0.84)kJ·mol^-1 for KBO₂·4/3H₂O was obtained from the standard molar enthalpies of formation of KCl(s)， H₃BO₃(s)， and H₂O(l). The standard molar entropy of formation of -422.94J·K^-1·mol^-1 and standard molar entropy of 163.47J·K^-1·mol^-1 for KBO₂·4/3H₂O were calculated from the thermodynamic relations. A group contribution method is applicable to KBO₂·4/3H₂O.     

水合六硼酸钡的合成与热化学研究

硼原子的硼酸盐种类繁多,结构复杂多样,其中,有一些硼酸盐具有特殊的性能,如:2ZnO·3B_2O_3·3.5H_2O、2CaO·3B_2O_3·5H_2O可用作阻燃材料~([1]),β-BaB_2O_4(β-BBO)~([2])、Ba_2Be_2B_2O_7~([3])、BaAl_2 B_2O7_~([4])等因其具有良好的光学性质,被广泛用作非线性光学材料.因此,进行硼酸盐的合成及性质研究有着重要的意义.     

Thermochemistry of heteroatomic compounds

The enthalpies of vaporization of different classes three-coordinated arsenic compounds have been determined according to their enthalpies of solution in hexane and molar refraction. The enthalpies of solvation of cyclic and acyclic As(III)-derivatives in hexane, carbon tetrachloride,p-xylene and pyridine are obtained and discussed. Part 6, see Ref. [1].     

Thermochemical properties of three piperidine derivatives

The standard (p ^o=0.1 MPa) molar energies of combustion for the crystalline 1-benzyl-4-piperidinol and 4-piperidine-piperidine, and for the liquid 4-benzylpiperidine, were measured by static bomb calorimetry, in oxygen, at T=298.15 K. The standard molar enthalpies of sublimation or vaporization, at T=298.15 K, of these three compounds were determined by Calvet microcalorimetry. Those values were used to derive the standard molar enthalpies of formation, at T=298.15 K, in their condensed and gaseous phase, respectively.     

水杨醛-1H-苯并三唑乙酰腙与RE（Ⅲ）配合物的热化学

在甲醇中，合成了6种稀土与水杨醛-1H-苯并三唑乙酰腙(C15H13N5O2，简称SBTH)的新配合物RE(HL)2ClO4(RE=Pr,Nd,Sm,Eu，Gd，Tb；HL=C15H13N5O2)，并对其进行了元素分析、摩尔电导率、瓜和1^H NMR的测定，确定了其组成．通过TG-DTG、DSC研究了配合物的热分解过程，得到了各配合物的分解焓，利用Kissinger。法及Ozawa法计算出各配合物主要分解阶段的表观活化能，测量了该系列配合物在二甲基甲酰胺(DMF)中不同浓度时的溶解焓．     

Enthalpies of mixing of acetonitrile with isomeric butanols: Enthalpies of hydrogen-bonded complexes

The enthalpies of mixing of four isomeric butanols with acetonitrile were determined at 30°C by a Calvet type microcalorimeter. All the four systems showed endothermic behaviour. The enthalpies of hydrogen bonded complex formation were determined by means of a thermochemical cycle. 1-butanol formed a stronger bonding (−13kJ/mole) than the other three isomers (−11.20kJ/mole). The strength of the H-bond of alcohol with C ≡ N is much less than that with C-N. NCL communication no. 4883     

The structure and thermochemistry of 3:4,5:6-dibenzo-2-hydroxymethylene-cyclohepta-3,5-dienenone (1) and some related compounds

Condensed and gas phase enthalpies of formation of 3:4,5:6-dibenzo-2-hydroxymethylene-cyclohepta-3,5-dienenone (1, (−199.1 ± 16.4), (−70.5 ± 20.5) kJ mol⁻¹, respectively) and 3,4,6,7-dibenzobicyclo[3.2.1]nona-3,6-dien-2-one (2, (−79.7 ± 22.9), (20.1 ± 23.1) kJ mol⁻¹) are reported. Sublimation enthalpies at T=298.15 K for these compounds were evaluated by combining the fusion enthalpies at T = 298.15 K (1, (12.5 ± 1.8); 2, (5.3 ± 1.7) kJ mol⁻¹) adjusted from DSC measurements at the melting temperature (1, (T _fus, 357.7 K, 16.9 ± 1.3 kJ mol⁻¹)); 2, (T _fus, 383.3 K, 10.9 ± 0.1) kJ mol⁻¹) with the vaporization enthalpies at T = 298.15 K (1, (116.1 ± 12.1); 2, (94.5 ± 2.2) kJ mol⁻¹) measured by correlation-gas chromatography. The vaporization enthalpies of benzoin ((98.5 ± 12.5) kJ mol⁻¹) and 7-heptadecanone ((94.5 ± 1.8) kJ mol⁻¹) at T = 298.15 K and the fusion enthalpy of phenyl salicylate (T _fus, 312.7 K, 18.4 ± 0.5) kJ mol⁻¹) were also determined for the correlations. The crystal structure of 1 was determined by X-ray crystallography. Compound 1 exists entirely in the enol form and resembles the crystal structure found for benzoylacetone.     

Thermochemical study of 2- and 3-alkyl substituted thiophenes

The standard (p ⁰=0.1 MPa) molar enthalpies of formation, in the condensed phase, of nine linear-alkyl substituted thiophenes, six in position 2- and three in position 3-, at T=298.15 K, were derived from the standard massic energies of combustion, in oxygen, to yield CO₂(g) and H₂SO₄·115H₂O(aq), measured by rotating-bomb combustion calorimetry. The standard molar enthalpies of vaporization of these compounds were measured by high temperature Calvet Microcalorimetry, so their standard molar enthalpies of formation, in the gaseous phase, were derived. The results are discussed in terms of structural contributions to the energetics of the alkyl-substituted thiophenes, and empirical correlations are suggested for the estimation of the standard molar enthalpies of formation, at T=298.15 K, for 2- and 3-alkyl-substituted thiophenes, both in the condensed and in the gaseous phases.     

咪唑醋酸离子液体热力学性质的理论研究

咪唑醋酸离子液体在催化、电化学、萃取等领域具有潜在的应用价值,对其热力学性质的深入研究将为其应用提供理论依据。本文采用密度泛函理论(DFT)方法和Born-Fajans-Haber (BFH)循环法对咪唑醋酸离子液体[C_nmim][OAc] (n=1-6)进行热力学性质的理论研究。计算其相变过程中的解离焓、汽化焓、熔化焓、晶格焓、溶解焓等,并与已有实验值进行比较。利用Gaussian 09程序在B3LYP/6-311+G(d, p)和M062X/TZVP两种水平下计算解离焓值,同时通过计算得到分子体积和总气相能的焓修正值,借助Matlab计算软件拟合得到汽化焓值,取得与已有实验值很好的一致性。使用Jenkins公式求得晶格能,计算得到晶格焓,最后利用BFH循环计算得到溶解焓。     

Enthalpies of crystallization of NaCl,KCl, LiCl·H2O,MgCl2 6H2O,CaCl2 6H2O and BaCl2·2H2O from aqueous solution at 298.15 K

The enthalpies of crystallization of NaCl, KCl, LiCl·H₂O, MgCl₂·6H₂O, CaCl₂·6H₂O and BaCl₂·2H₂O from aqueous solution were determined by means of different calculation methods on the basis of the earlier-measured differential and integral enthalpies of solution of the above salts. The obtained crystallization enthalpies are discussed and compared with the appropriate literature data.

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Zusammenfassung Es wurden die Kristallisationenthalpien des NaCl, KCl, LiCl·H₂O, MgCl₂·6H₂O, CaCl₂·6H₂O und BaCl₂·2H₂O aus wässerigen Lösungen bestirnt. Es wurden vorher gemessene differenzierte und integrale Enthalpien von oben genannten gelösten Salze ausgenutzt, bei denen verschiedene Berechnungsmethoden angewandt wurden. Die gewonenen Kristallisationenthalpien wurden mit entsprechenden Literaturangaben erörtert und vergliechen.

     

Standard Enthalpies of Formation for Some Semi-products At the Synthesis of Poly(ethylene) Terephthalate

The enthalpies of combustion for 4-formylbenzoic acid (I), 4-methylbenzyl alcohol (II), and trimethyl 1,2,4-benzenetricarboxylate (III) were determined by the bomb calorimetry method. Enthalpies of sublimation for I and II were measured with a calorimeter. The contributions of different substituents to the standard enthalpies of formation for benzene derivatives in the gas state were derived. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermochemistry of Amines: Experimental Standard Molar Enthalpies of Formation of N-Alkylated Piperidines

The standard molar enthalpies of formation _f H _m ^° (l) at the temperature T = 298.15 K were determined using combustion calorimetry for N-methylpiperidine (A), N-ethylpiperidine (B), N-propylpiperidine (C), N-butylpiperidine (D), N-cyclopentylpiperidine (E), N-cyclohexylpiperidine (F), and N-phenylpiperidine (G). The standard molar enthalpies of vaporization _l ^g H ^{m °} of these compounds were obtained from the temperature variation of the vapor pressure measured in a flow system. From these data the following standard molar enthalpies of formation in gaseous phase _f H _m ^° (g) were derived for: A –(61.39 ± 0.88); B –(88.1 ± 1.3); C –(105.81 ± 0.66); D –(126.2 ± 1.3); E ( –88.21 ± 0.75); F –(135.21 ± 0.94); G (70.3 ± 1.4) kJ · mol^–1. They are used to determine the strain enthalpies of the cyclic amines A–G. The N-alkylated piperidine rings have been found to be about strainless.     

Experimental Enthalpies of Formation and Strain of the Methylated 1-Amino-2-phenylethanes

The standard molar enthalpies of formation H _f ^00B0; (liq) at the temperature t = 298.15 K were determined using combustion calorimetry for N-methyl-3-methyl-3-phenyl-2-butaneamine 1a, N,N-dimethyl-3-methyl-3-phenyl-2-butaneamine 1b N-methyl-2,3-dimethyl-3-phenyl-2-butaneamine 2a, and N,N-dimethyl-2,3-dimethyl-3-phenyl-2-butaneamine 2b. The standard molar enthalpies of vaporization H _vap ^00B0; of these compounds were obtained from the temperature variation of the vapor pressure measured in a flow system. The following standard molar enthalpies of formation in gaseous phase H _f ^00B0; (g) are obtained from these data: for 1a – 10.9 ± 1.9; 1b – 3.6 ± 1.8; 1c – 26.6 ± 1.4, and 1d – 23.0 ± 1.8 kJ mol^–1. From the standard molar enthalpies of formation for gaseous compounds which are available in the literature, improved values for the increments of the Benson group addivitiy scheme of amines were calculated. They are used to determine the strain enthalpies of the amines 1 and 2 from this investigation.     

Enthalpic determinations of aliphatic ester-solvent systems with correlations

Calorimetric measurements were carried out on ester-solvent systems where the esters were H(CH₂)_xCOO(CH₂)_yH, with x and y varying from 1 to 5, and the solvents were n-hexane and 1,2-dichloroethane. Calculation of the enthalpies of cavity formation enabled the enthalpies of interaction to be determined. Both enthalpies correlated with number of carbon atoms N, equal to x+y in the esters, giving for 1,2-dichloroethane

Structure-property relationships in ILs: A study of the alkyl chain length dependence in vaporisation enthalpies of pyridinium based ionic liquids

The enthalpies of vaporization for the series of pyridinium-based ionic liquids with bis(trifluoromethylsulfonyl)imide anion [CnPy][NTf2] (n = 2, 3, 4, 5, and 6) have been determined with the quartz crystal microbalance technique combined with the Langmuir evaporation. The linear dependence of vaporization enthalpies on the chain length has been revealed. New approach based on volumetric, surface tension, and speed of sound measurements has been developed for estimation of heat capacity differences between gas and liquid phase, which were required for adjustment of measured vaporization enthalpies to the ref- erence temperature 298 K.     

氯化烷基咪唑系列离子液体标准摩尔燃烧焓和生成焓

用精密氧弹热量计测定了4种离子液体: 氯化1-甲基-3-乙基咪唑(C2MIC), 氯化1-甲基-3-丁基咪唑(C4MIC), 氯化1-甲基-3-戊基咪唑(C5MIC)和氯化1-甲基-3-己基咪唑(C6MIC)的燃烧热, 计算了它们的标准摩尔燃烧焓 和标准摩尔生成焓 , 结合文献中的标准摩尔溶解焓, 估算了烷基咪唑阳离子在水溶液中的标准摩尔生成焓, 以及亚甲基对标准摩尔燃烧焓和标准摩尔生成焓的贡献.     

Thermochemistry of heteroatomic compounds

The enthalpies of solvation of four geometric isomers of 2,5-dimethyl-1-phenyl-1-thioxophosphorinan-4-one in chloroform, nitrobenzene, and methanol were calculated using the enthalpies of vaporization of the isomers determined by the modified Solomonov—Konovalov method from the enthalpies of solution of the compounds in CCl₄ andp-xylene and molar refractions. The enthalpies of formation (ΔH _f ^o) of the isomers in the condensed and gas phase were assessed in the framework of Benson's group additivity scheme by summing the ΔH _f ^o values for phosphacycloketone fragments obtained from molecular mechanics calculations with the contributions of the phenyl group and S atom attached to the P atom. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1533–1536, September, 2000.     

Standard molar enthalpies of formation of [RE(Gly)<Subscript>4</Subscript>(Im)(H<Subscript>2</Subscript>O)](ClO<Subscript>4</Subscript>)<Subscript>3</Subscript> (<Emphasis Type="Italic">RE</Emphasis>=Eu,Sm)

The two complexes, [RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)(RE = Eu, Sm), have been synthesized and characterized. The standard molar enthalpies of reaction for the following reactions, RECl₃·6H₂O(s)+4Gly(s)+Im(s)+3NaClO₄(s) = =[RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)+3NaCl(s)+5H₂O(l), were determined by solution-reaction colorimetry. The standard molar enthalpies of formation of the two complexes at T = 298.15 K were derived as Δ_f H _m^Θ {Eu(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = = −(3396.6±2.3) kJ mol⁻¹ and Δ_f H _m^Θ {Sm(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = −(3472.7±2.3) kJ mol⁻¹, respectively.     

Thermochemistry of Cs(hydrogen phthalate) and Cs2(terephthalate)

New compounds of phthalic acid, Cs(HPHT), and terephthalic acid, Cs₂(TPA), have been synthesized. The enthalpy of solution of Cs(HPHT) in water was determined and combined with the standard molar enthalpies of formation of CsOH(aq), H₂O(l) and phthalic acid(s) to calculate the standard molar enthalpy of formation of Cs(HPHT) of −(1035.6 ± 0.5) kJ mol⁻¹. The enthalpies of solution of Cs₂(TPA) and TPA in approximately 0.11 mol dm⁻³ CsOH were determined and combined with the standard molar enthalpies of formation of TPA(s), H₂O(l) and CsOH(aq, 1:500) to calculate the standard molar enthalpy of formation of Cs₂(TPA) of −(1266.2 ± 0.3) kJ mol⁻¹.