Synthesis,Characterization and Standard Molar Formation Enthalpy of [Sm(C_7H_5O_3)_2(C_4H_6NO_2S)]·2H_2O

[Sm（C7H5O3）2（C4H6NO2S）]·2H2O was synthesized from the reaction of samarium chloride hexahydrate with salicylic acid and thioproline,and characterized by IR,elemental analysis and thermogravimatric analysis.The standard molar enthalpies of the solutions of SmCl3·6H2O（s）,2[C7H6O3（s）],[C4H7NO2S（s）] and [Sm（C7H5O3）2·（C4H6NO2S）·2H2O（s）] in a mixed solvent of absolute ethyl alcohol,dimethyl formamide（DMF） and 3 mol/L HCl were,respectively,determined by calorimetry to be ΔsHm^Θ [SmCl3·6H2O（s）,298.15 K]=（-46.68±0.15） kJ/mol,ΔsHm^Θ [2C7H6O3（s）,298.15 K]=（25.19±0.02） kJ/mol,ΔsHm^Θ [C4H7NO2S（s）,298.15 K]=（16.20±0.17） kJ/mol and ΔsHm^Θ {[Sm（C7H5O3）2（C4H6NO2S）]·2H2O（s）,298.15 K}=（-81.24±0.67） kJ/mol.The enthalpy change of the reaction SmCl3·6H2O（s）＋2C7H6O3（s）＋C4H7NO2S（s）=[Sm（C7H5O3）2（C4H6NO2S）]·2H2O（s）＋3HCl（g）＋4H2O（l） was determined to be ΔrHm^Θ =（123.45±0.71） kJ/mol.From the data in the literature,the standard molar formation enthalpy of [Sm（C7H5O3）2（C4H6NO2S）]·2H2O（s） was estimated to be Δf Hm^Θ {[Sm（C7H5O3）2（C4H6NO2S）]·2H2O（s）,298.15 K}=（-2912.03±3.1） kJ/mol through Hess＇ law.

Lattice potential energy and standard molar enthalpy in the formation of 1-dodecylamine hydrobromide (1-C_(12)H_(25)NH_3 ·Br)(s)

This paper reports that 1-dodecylamine hydrobromide （1 C12H25NH3.Br）（s） has been synthesized using the liquid phase reaction method. The lattice potential energy of the compound 1-C12H25NH3.Br and the ionic vol- ume and radius of the 1-C12H25NH3＋ cation are obtained from the crystallographic data and other auxiliary ther- modynamic data. The constant-volume energy of combustion of 1 C12H25NH3.Br（s） is measured to be AcUo（1 C12H25NH3.Br, s） = （7369.03-4-3.28） kJ.mo1-1 by means of an RBC-II precision rotating-bomb combustion calorime- ter at T=（298.15~0.001） K. The standard molar enthalpy of combustion of the compound is derived to be △cHo（1- C12H25NH3.Br, s）=- （7384.52±3.28） kJ.mo1-1 from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound is calculated to be △fHo（1-C12H25NH3.Br, s）=-（1317.86~3.67） kJ.mo1-1 from the standard molar enthalpy of combustion of the title compound and other auxiliary thermodynamic quantities through a thermochemical cycle.

Crystal Structure, Thermal Decomposition Behavior and the Standard Molar Enthalpy of Formation of a Novel 3D Hydrogen- Bonded Supramolecular [Co（HnicO）2·（H2O）2]

热水的合成和 X 光检查描绘了 3D 超分子的网络被构造由[公司(HnicO )

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

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.

Relationship between the Standard Enthalpy of Formation and the Ratio of Standard Enthalpy of Formation and Exothermic Denitration Decomposition Peak Temperature of M(NTO)_n

A relationship is established, using the least squares method, between the standard enthalpy of formation and the standard enthalpy of formation divided by the exothermic denitration decomposition peak absolute temperature corresponding to β →0.

Standard Molar Enthalpy of Formation of RE(C_5H_8NS_2)_3(C_(12)H_8N_2)

Four solid ternary complexes of RE (C_5H_8NS_2)_3(C_(12)H_8N_2) (RE=Eu, Gd, Tb, Dy) were synthesized in absolute ethanol by rare earth chloride low hydrate with the mixed ligands of ammonium pyrrolidinedi-thiocarbamate (APDC) and 1, 10-phenanthroline·H_2O (o-phen·H_2O) in the ordinary laboratory atmosphere without any cautions against moisture or air sensitivity. IR spectra of the complexes show that the RE^(3+) coordinated with six sulfur atoms of three PDC^- and two nitrogen atoms of o-phen·H_2O. It was assumed that the coordination number of RE^(3+) is eight. The constant-volume combustion energies of the complexes, Δ_cU, were determined as (-16937 88±9 79 ), (-17588 79±8 62 ), ((-17747 14±)8 25 ) and (-17840 37±8 87 ) kJ·mol^(-1), by a precise rotating-bomb calorimeter at 298.15 K. Its standard molar enthalpies of combustion, Δ_cH~θ_m, and standard molar enthalpies of formation, Δ_fH~θ_m, were calculated as (-16953 37±9 79), (-17604 28±8 62), (-17762 63±8 25), (-17855 86±8 87) kJ·mol^(-1) and (-857.04±10.52), (-282.43±9.58), (-130.08±9.13), (-55.75±9.83) kJ·mol^(-1).

Synthesis and Determination of Standard Molar Enthalpies of Formation for Complexes of Rare Earth Isothiocyanates with Glycine

Four solid complexes of rare earth isothiocyanates with glycine were synthesized. They were characterized by chemical analysis, elemental analysis, Infrared spectra, X-ray powder diffraction and TO-DSC analysis. Their chemical formulae were proved to be RE(NCS)2.Gly .H2O, where RE is La, Ce, Pr or Nd. The integral heats of solution of RE(NCS)3.3Gly. H2O in water, of RE(NCS)2. 7H2O in aqueous glycine solution and of glycine in water have been measured calorimetricaliy at 298. 15K. By means of a thermochemical cycle suggested in this paper, the standard molar enthalpies of formation for RE(NCS)2. 3Gly.H2O(c) were obtained and their lattice energies were calculated.

Low-temperature heat capacities and standard molar enthalpy of formation of 4-(2-aminoethyl)-phenol (C_8H_(11)NO)

This paper reports that low-temperature heat capacities of 4-（2-aminoethyl）-phenol （C8H11NO） are measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15K were calculated and tabulated at the interval of 5K. The energy equivalent, εcalor, of the oxygen-bomb combustion calorimeter has been determined from 0.68g of NIST 39i benzoic acid to be εcalor=（14674.69±17.49）J·K^-1. The constant-volume energy of combustion of the compound at T=298.15 K was measured by a precision oxygen-bomb combustion calorimeter to be ΔcU=-（32374.25±12.93）J·g^-1. The standard molar enthalpy of combustion for the compound was calculated to be ΔcHm = -（4445.47 ± 1.77） kJ·mol^-1 according to the definition of enthalpy of combustion and other thermodynamic principles. Finally, the standard molar enthalpy of formation of the compound was derived to be ΔfHm（C8H11NO, s）=-（274.68 ±2.06） kJ·mol^-1, in accordance with Hess law.

Low-temperature heat capacities and standard molar enthalpy of formation of N-methylnorephedrine C11H17NO（s）

This paper reports that low-temperature heat capacities of N-methylnorephedrine C11H17NO（s） have been measured by a precision automated adiabatic calorimeter over the temperature range from T=78K to T=400K. A solid to liquid phase transition of the compound was found in the heat capacity curve in the temperature range of T=342-364 K. The peak temperature, molar enthalpy and entropy of fusion of the substance were determined. The experimental values of the molar heat capacities in the temperature regions of T=78-342 K and T=364-400 K were fitted to two poly- nomial equations of heat capacities with the reduced temperatures by least squares method. The smoothed molar heat capacities and thermodynamic functions of N-methylnorephedrine C11H17NO（s） relative to the standard refer- ence temperature 298.15 K were calculated based on the fitted polynomials and tabulated with an interval of 5 K. The constant-volume energy of combustion of the compound at T=298.15 K was measured by means of an isoperibol precision oxygen-bomb combustion calorimeter. The standard molar enthalpy of combustion of the sample was calculated. The standard molar enthalpy of formation of the compound was determined from the combustion enthalpy and other auxiliary thermodynamic data through a Hess thermochemical cycle.

Standard Molar Enthalpy of Formation of Morin Studied by Rotating-Bomb Combustion Calorimetry

Flavonols are plant nature. Morin and other related pigments that are ubiquitous in plant flavonols have come into recent prominence because of their usefulness as anticancer, antitumor, anti-AIDS, and other important therapeutic activities of significant potency and low systemic toxicity. The heat of combustion of morin （molecular formula, C15H10O7·H2O） in oxygen was measured by a rotating-bomb type combustion calorimeter, the standard molar enthalpy of combustion of morin at T = 298.15 K was determined to be △cH^ m （C15H10O7·H2O, s） = - （5 937.99±2.99） kJ·mol^-1. The derived standard molar enthalpy of the formation of morin in solid powder state at T = 298.15 K, △fH^ m（C15H10O7·H2O, s）, was -（1 682.12 ± 3.58） kJ·mol^1, which provide an accurate data of the stability of morin to the pharmacy and pharmacology.

Preparation and Standard Formation Enthalpy of 2-Amino-4,6-dimethylpyrimidine and Its Related Complexes of Copper

The complexes of hydrous copper chloride and copper nitrate with 2-amino-4,6-dimethylpyrimidine(ADMP) were prepared via reflux in alcohol. The compositions of the complexes were identified as Cu(ADMP) 2Cl 2·2H 2O(b) and Cu(ADMP)(NO 3) 2·H 2O(c) by chemical and elemental analyses. The complexes were characterized by IR, XPS, 1H NMR and TG-DTG techniques. The constant-volume combustion energies of ADMP and the complexes, Δ c E , were determined by a precise rotating-bomb calorimeter at 298 15 K. They were (-3664 53±1 18), (-4978 47±2 72) and (-1696 70±1 36) kJ/mol, respectively. Their standard enthalpies of combustion, Δ c H 0 m, and standard enthalpies of formation, Δ f H 0 m, were calculated to be (-3666 39±1 18), (-4977 23±2 72), (-1691 12±1 36) kJ/mol and (19 09±1 43), (-2041 80±3 29), (-2397 24±1 65) kJ/mol, respectively.

Standard energies of combustion and standard enthalpies of formation for the complexes RE (Et_2dtc)_3(phen) (RE = Ho,Er,Tm,Yb,Lu)

The treatment of RECl3.xH2O （RE = Ho, Er, Tm, Yb, Lu; x = 3-4） with sodium diethyldithiocarbamate （NaEtEdtc-3H2O） and 1,10-phenanthroline hydrate （o-phen.H2O） in absolute ethanol yielded five ternary solid complexes RE（EtEdtC）a（phen）. IR spectra of the complexes showed that RE^3＋ coordinated to two sulfur atoms in NaEt2dtc and two nitrogen atoms in o-phen. The constant-volume energies of combustion of the complexes have been determined by a precise rotating-bomb calorimeter at 298.15 K. The standard enthalpies of combustion and standard enthalpies of formation were calculated.

Correlation between the Standard Formation Enth alpy and the Path Index of Pyridine Derivatives

A formulated as △fH m ? (PPDs,g)=a+ΣbiPi + cifi is put forward for estimating standard formation enthalpies of pyridine-derivatives (PDDs), in which,P i is path index andc i f i is an amended term of interaction between substituent and N atom on pyridine ring. The Calculations based on the model were carried out for some pyridine-derivatives. The values of standard formation enthalpy calculated are consistent with those in literature.

Standard Enthalpy of Formation of Monoclinic Ammonium Paratungstate

The enthalpy of reaction for the decomposition of monoclinic ammonium paratungstate,(NH_4 )_10 H_2, W_12 O_424H_2 O(s), was measured using a HT-1000 calorimeter. From the experimentalresults, the standard enthalpy of formation of ammonium paratlingstate at 298.15 K is obtained.

Investigation on molar heat capacity, standard molar enthalpy of combustion for guaiacol and acetyl guaiacol ester

The molar heat capacities(C_p) of guaiacol(CAS 90-50-1) and acetyl guaiacol ester(AGE, CAS 613-70-7) were determinated from 290 K to 350 K by differential scanning calorimetry(DSC), and expressed as a function of temperature. Two kinds of group contribution models were used to estimate the molar heat capacities of both guaiacol and AGE, the average relative deviation is less than 10%. The standard molar enthalpies of combustion of guaiacol and AGE were- 3590.0 k J·mol^(-1)and- 4522.1 k J·mol^(-1) by a precise thermal isolation Oxygen Bomb Calorimeter. The standard molar enthalpies of formation of guaiacol and AGE in a liquid state at298.15 K were calculated to be- 307.95 k J·mol^(-1) and- 448.72 k J·mol^(-1), respectively, based on the standard molar enthalpies of combustion. The thermodynamic properties are useful for exploiting the new synthesis method, engineering design and industry production of AGE using guaiacol as a raw material.

Studies on Standard Formation Enthalpies of Rare Earth Compounds by Using Structural Parameters

The atomic structural parameter P-i = (Z(i)*/n(i)*) (1 + n(i)*/n(i)) (1 + m(i)/Z) and the molecular structural parameter [GRAPHICS] are defined. The standard formation enthalpies (Delta(f)H(m)(phi)) of 74 species of rare earth compounds were studied with P, and the correlation coefficient is R > 0.94. The structural factors and the properties of rare earth compounds are influenced by the Z(i)*, n(i)*, n(i), m(i), Z. This study has special referential value to predict the properties of rare earth compounds.

Thermochemical Study on Coordination Complex of Samarium with Salicylic Acid and 8-Hydroxyquinoline

The coordination complex Sm（C7H5O2）2·（C9H6NO）, synthesized from the reaction of samarium chloride sixhydrate with salicylic acid and 8-hydroxyquinoline, was characterized with IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard molar enthalpies of solution of [ SmCl3·6H2O （s） ], [ 2C7H6O3 （s） ], [ C9H7NO （ s ） ] and [ Sm （C7H5O3） 2·（ C9H6NO ） （ s ） ] in the calorimetric solvent were determined with the solution-reaction isoperibol calorimeter at 298.15 K to be △sHm^- [ SmCl3·6H2O （s）, 298.15 K ] = - 103.98 ± 0.04 kJ·mol^-1, △sHm^- [2 C7H6O3 （s）, 298.15 K] = 16.35±0.14 kJ·mol^-1,△sHm^-[C9H7NO （s）, 298.15 K] = -6.11±0.08 kJ·mol^-1 and △sHm^-[Sm（C7H5O3）2·（C9H6NO） （s）, 298.15 K] = - 130.08 ± 0.04 kJ·mol^-1, respectively. The enthalpy was determined to be △rHm^- = 89.59 ±0.18 kJ·mol^-1 for the reaction SmCl3·6H2O（s） ＋ 2C7H6O3（s） ＋ C9H7NO（s） = Sm （C7H5O3） 2·（C9H6NO） （ s ） ＋ 3HCl （g） ＋ 6H2O （ l ）. According to the above results and the data given in literature and through Hess＇ law, the standard molar enthalpy of formation of Sin（ C7H5O3 ）2·（C9H7NO）（s） was estimated to be △rHm^- [ Sm （C7H5O3）2·（C9H6NO） （s）, 298.15 K] = - 2055.9 ± 3.03 kJ·mol^-1.

Thermochemical Study on Ternary Solid Complex of La(Gly)_2(Ala)_3Cl_3·2H_2O(s)

The complex of lanthanum chloride with Glycine and Alanine,La（Gly）2（Ala）3Cl3·2H2O,was synthesized and characterized by IR,elementary analysis,thermogravimetric analysis,and chemical analysis.The dissolution enthalpies of LaCl3 ·7H2O（s）,2Gly（s）＋ 3Ala（s）and La（Gly）2（Ala）3Cl3 ·2H2O（s）were determined in 2 mol·L-1 HCl by a solution-reaction isoperibol calorimeter.By designing a thermochemical cycle in terms of Hess＇ Law and through calculation,the reaction enthalpy of lanthanum chloride seven-hydrate with Glycine and Alanine was obtained：ΔrHθm（298.15 K）=（29.652±0.504）kJ·mol-1,and the standard enthalpy of formation of La（Gly）2（Ala）3Cl3·2H2O（s）ΔfHθm [La（Gly）2（Ala）3Cl3·2H2O,s,298.15 K]=-4467.6±8.3 kJ·mol-1.

Thermochemical Properties of Ternary Complexes of RE Perchlorate with Glycine and Imidazole

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Thermochemical Properties of the Complexes RE(HSal)_3·2H_2O (RE=La,Ce,Pr,Nd,Sm)

Five solid rare earth salicylate complexes were synthesized by low hydrated lathanide chloride and salicylic acid. The complexes in this experiment were identified as the general formula RE（HSal）3·2H2O（RE = La, Ce, Pr, Nd, Sm） by elemental analysis and EDTA volumetric analysis. IR spectra of the complexes show that carboxyl of salicylic acid coordinates to RE^3＋ ions. Electrochemical behaviors of the complexes on the glass-carbon electrode were researched with cyclic voltammetry （CV）. It is indicated that the electrochemical process of the complexes is a one-electron redox process and the electrochemical reversibility of complexes is less than that of the lanthanide chlorides. The constant-volume combustion energies of complexes,△c U, were determined with a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, △cH^θm, and standard molar enthalpies of formation, △fH^θm, were calculated.