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1.
Novel anilino-pyrimidine fungicides, pyrimethanil maleic salt, and pyrimethanil fumaric salt (C28H30N6O4) were synthesized by a chemical reaction of pyrimethanil with maleic acid/fumaric acid. The low-temperature heat capacities of the two compounds were measured with an adiabatic calorimeter from 80 to 350 K. The heat capacities of pyrimethanil fumaric salt are bigger than that of pyrimethanil maleic salt in the measurement temperature range. The thermodynamic function data relative to 298.15 K were calculated based on the heat capacity-fitted curves. The melting points, the molar enthalpies (Δfus H m), and entropies (Δfus S m) of fusion of pyrimethanil maleic salt and pyrimethanil fumaric salt were determined from their DSC curves. The values indicate that pyrimethanil fumaric salt was more thermostable than pyrimethanil maleic salt. The constant-volume energies of combustion (Δc U m o ) of pyrimethanil maleic salt and pyrimethanil fumaric salt were measured using an isoperibol oxygen bomb combustion calorimeter at T = (298.15 ± 0.001) K. From the Hess thermochemical cycle, the standard molar enthalpies of formation of the two compounds were derived and determined to be Δf H m o (pyrimethanil maleic salt) = ?459.3 ± 4.9 kJ mol?1 and Δf H m o (pyrimethanil fumaric salt) = ?557.2 ± 4.8 kJ mol?1, respectively. The results suggest that pyrimethanil fumaric salt is more chemically stable than pyrimethanil maleic salt.  相似文献   

2.
Potassium ferrate, K2FeO4(cr), has numerous promising environmental applications. An aqueous thermodynamic model applicable to high ionic strengths is essential for guiding its applications. In this study, a thermodynamic model is developed for the solubility of K2FeO4(cr) in aqueous alkali metal hydroxide solutions, from 283.15 to 333.15 K to high ionic strengths, up to saturation of KOH and NaOH, based on the Pitzer activity coefficient model for aqueous species. The solubility products for K2FeO4(cr) at infinite dilution in the temperature range from 283.15 to 333.15 K were obtained. Based on the thermodynamic solubility product of K2FeO4(cr) at 298.15 and its temperature dependence, in combination with thermodynamic properties for $ {\text{FeO}}_{4}^{2 - } $ FeO 4 2 ? and K+ from the literature, standard thermodynamic properties of K2FeO4(cr) at 298.15 K and 0.1 MPa (1 bar) are derived for the first time as follows: Δf G 0 = ?(896 ± 8) kJ·mol?1, Δf H 0 = ?(1026 ± 4) kJ·mol?1, and S 0 = (130 ± 17) J·mol?1·K?1. Using the above thermodynamic properties for K2FeO4(cr), the potential presence or preservation of K2FeO4(cr) in the Martian soils under the conditions relevant to Mars were quantitatively evaluated. Thermodynamic calculations pertaining to the Martian conditions indicate that the presence or preservation of K2FeO4(cr) as a strong oxidant in the Martian soils can be supported.  相似文献   

3.
The chemisorption of CO2 by aqueous-hindered amines has been investigated experimentally and theoretically. Negative-ion ESI–MS analysis of solutions containing a sterically hindered amine and a source of 13CO2 reveals peaks corresponding to [M–H + 45]?. These ions readily lose 45 Da when subjected to collisional activation, and together with other key fragments confirms the generation of the 13C-labelled carbamate derivatives. The thermochemistry of the two key capture reactions: $$2.{\text{amine }} + {\text{ CO}}_{ 2} { \leftrightarrows }{\text{amine}} - {\text{CO}}_{ 2}^{ - } + {\text{ amine}} - {\text{H}}^{ + } {\kern 1pt} \quad 1:{\text{carbam}}$$ $${\text{amine }} + {\text{ CO}}_{ 2} + {\text{ H}}_{ 2} {\text{O}}{ \leftrightarrows }{\text{HCO}}_{ 3}^{ - } + {\text{ amine}} - {\text{H}}^{ + } \quad 2:{\text{ bicarb}}$$ at 298 K was modelled using composite chemistry methods, CCSD(T), DFT, and SM8 free energies of solvation. The aqueous reaction free energies (ΔG 298) for reaction 1 are predicted to be more negative than ΔG 298 for reaction 2 when amine = ammonia, 2-aminoethanol (MEA), 2-amino-2-methyl-1-propanol (AMP), 2-amino-2-hydroxymethyl-propane-1,3-diol (tris), and 2-piperidinemethanol (2-PM). For AMP, tris, and 2-PM, activation free energies ΔG 298 ? for reaction 1 (SM8 + CCSD(T)/6-311 ++G(d,p)//M08-HX/MG3S: 38–67 kJ mol?1) are smaller than the corresponding values for 2 (109–113 kJ mol?1). For 2-PM, the computed carbamate ΔG 298 ? (38 kJ mol?1) is comparable to the MEA value (45 kJ mol?1), whereas the primary amines with tertiary alpha carbons have slightly larger values (60–70 kJ mol?1). The organic amine values are much lower than the value for ammonia (93 kJ mol?1). The results indicate CO2 chemisorption proceeds via a carbamate intermediate for all aqueous primary and secondary amines. Hindered carbamates are susceptible to further chemical transformations following their formation.  相似文献   

4.
For the equilibrium solid phases occurring in the systems: KCl?KBr?H2O, K2SO4?(NH4)2SO4?H2O and KNO3?NH4NO3?H2O, the concentration dependencies of differential solution enthalpies, Δsol H 2 for several crystallization paths, were measured. The limiting differential solution enthalpies, Δsol H 2 0 , were determined by extrapolation of the above dependencies to the ionic strength,I m 0 , corresponding to the appropriate binary solutions. For KCl?KBr?H2O system only, the clear dependence between Δsol H 2 0 andI m 0 values was found and discussed.  相似文献   

5.
6.
The product from reaction of samarium chloride hexahydrate with salicylic acid and Thioproline, [Sm(C7H5O3)2·(C4H6NO2S)]·2H2O, was synthesized and characterized by IR, elemental analysis, molar conductance, and thermogravimetric analysis. The standard molar enthalpies of solution of [SmCl3·6H2O(s)], [2C7H6O3(s)], [C4H7NO2S(s)] and [Sm(C7H5O3)2·(C4H7NO2S)·H2O(s)] in a mixed solvent of absolute ethyl alcohol, dimethyl sulfoxide(DMSO) and 3 mol L?1 HCl were determined by calorimetry to be Δs H m Φ [SmCl3 δ6H2O (s), 298.15 K]= ?46.68±0.15 kJ mol?1 Δs H m Φ [2C7H6O3 (s), 298.15 K]= 25.19±0.02 kJ mol?1, Δs H m Φ [C4H7NO2S (s), 298.15 K]=16.20±0.17 kJ mol?1 and Δs H m Φ [Sm(C7H5O3)2·(C4H6NO2S)]·2H2O (s), 298.15 K]= ?81.24±0.67 kJ mol?1. The enthalpy change of the reaction (1) $$ SmCl_3 \cdot 6H_2 O(s) + 2C_7 H_6 O_3 (s) + C_4 H_7 NO_2 S(s) = Sm(C_7 H_5 O_3 )_2 \cdot (C_4 H_6 NO_2 S) \cdot 2H_2 O(s) + 3HCl(g) + 4H_2 O(1) $$ was determined to be Δs H m Φ =123.45±0.71 kJ mol?1. From date in the literature, through Hess’ law, the standard molar enthalpy of formation of Sm(C7H5O3)2(C4H6NO2S)δ2H2O(s) was estimated to be Δs H m Φ [Sm(C7H5O3)2·(C4H6NO2S)]·2H2O(s), 298.15 K]= ?2912.03±3.10 kJ mol?1.  相似文献   

7.
In order to obtain a clue to the antitumor mechanism of $\left[ {{\text{Me}}_{ 3} {\text{NH}}} \right]_{ 6} \left[ {{\text{H}}_{ 2} {\text{Mo}}_{ 1 2}^{\text{V}} {\text{O}}_{ 2 8} \left( {\text{OH}} \right)_{ 1 2} \left( {{\text{Mo}}^{\text{VI}} {\text{O}}_{ 3} } \right)_{ 4} } \right]$ ·2H2O (PM-17), the interaction of PM-17 with flavin mononucleotide (FMN) as a prosthetic group of the flavoprotein has been investigated by both polarographic analysis and isothermal titration calorimetry (ITC) technique at the physiological solution pH (7.5). The half-wave potential (?0.50 V vs. Ag/AgCl) of the d.c. polarogram for the quasi-reversible one-electron reduction of FMN was shifted by PM-17 toward a more positive potential with a resultant deviation from one-electron reduction to formally more than one-electron reduction waves. The PM-17 effect on the d.c. polarogram could be explained by a variety of FMN···(PM-17)n (n > 0) aggregates with multiple conformations which was supported by the thermodynamic parameters (ΔH = ?29.7 kJ mol?1, ΔS = ?28.2 J mol?1 K?1, ΔG = ?21.5 kJ mol?1, and number of FMN in the binding with PM-17 (N) = 0.053 at 20 °C) estimated by the ITC technique. A large conformational change of the FMN domain by the FMN···(PM-17)n aggregates is suggested to prevent the movement of the FMN centers into close proximity with nicotinamide adenine dinucleotide (NADH) with a resultant depression of the electron transport in NADH dehydrogenase.  相似文献   

8.
A noval anilino-pyrimidine fungicide, pyrimethanil butanedioic salt (C28H32N6O4), was synthesized by a chemical reaction of pyrimethanil and butanedioic acid. The low-temperature heat capacities of the compound were measured with an adiabatic calorimeter from 80 to 380 K. The thermodynamic function data relative to 298.15 K were calculated based on the heat capacity fitted curve. The thermal stability of the compound was investigated by TG and DSC. The TG curve shows that pyrimethanil butanedioic salt starts to sublimate at 455.1 K and totally changes into vapor when the temperature reaches 542.5 K with the maximal speed of weight loss at 536.8 K. The melting point, the molar enthalpy (Δfus H m), and entropy (Δfus S m) of fusion were determined from its DSC curves. The constant-volume energy of combustion (Δc U m) of pyrimethanil butanedioic salt was measured by an isoperibol oxygen-bomb combustion calorimeter at T = (298.15 ± 0.001) K. From the Hess thermochemical cycle, the standard molar enthalpy of formation was derived and determined to be Δf H m o (pyrimethanil butanedioic salt)=?285.4 ± 5.5 kJ mol?1.  相似文献   

9.
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, Hθm, have been calculated as (‐1842.01 ± 2.13) kJ·mol?1 and (‐1136.16 ± 4.45) kJ·mol?1, respectively.  相似文献   

10.
A new chelate (η5-C5H5)2Ti(SB)2, whereSB=O, N donor Schiff base salicylidene-4-methylaniline, was synthesized. The course of thermal degradation of the chelate was studied by thermogravimetric (TG) and differential thermal analysis (DTA) under dynamic conditions of temperature. The order of the thermal decomposition reaction and energy of activation was calculated from TG curve while from DTA curve the change in enthalpy was calculated. Evaluation of the kinetic parameters was performed by Coats-Redfern as well as Piloyan-Novikova methods which gaven=1, ΔH=1.114 kJ·mol?1, ΔE=27.01 kJ·mol?1, ΔS=?340.12 kJ·mol?1·K?1 andn=1, ΔH=1.114 kJ·mol?1, ΔE=20.01 kJ·mol?1, ΔS=?342.60 kJ·mol?1·K?1, respectively. The chelate was also characterized on the basis of different spectral studies viz. conductance, molecular weight, IR, UV-visible and1H NMR, which enabled to propose an octahedral structure to the chelate.  相似文献   

11.
From the heats of solution for Ba(NO3)2 (c), KNO3 (c; II), and Ba(NO3)2 · 2 KNO3 (c) the heat of combination of the double salt from its component salts ΔH 298 0 =(?2.168±0.028) kcal · mole?1 and the standard heat of formation ΔH f,298 0 =?474.75 kcal · mole?1 have been determined. The values of derived thermodynamic properties are summarized in table 4.  相似文献   

12.
Peanut-like CaMoO4 micro/nano structures with three different sizes were harvested by a simple reverse-microemulsion method at room temperature. Employing synthesized micro/nano CaMoO4 and HCl as reaction systems, thermodynamic parameters such as standard molar enthalpy of reaction Δr H m θ , standard molar Gibbs free energy of activation Δ r G m θ , standard molar enthalpy of activation Δ r H m θ , and standard molar entropy of activation Δ r S m θ were successfully acquired for the first time by in situ microcalorimetry. Furthermore, change regularities of the thermodynamic parameters for the micro/nano reaction systems were obtained and discussed. It demonstrated that size effect has significant influence on thermodynamic parameters of micro/nano material reaction systems.  相似文献   

13.
Membrane introduction mass spectrometry (MIMS) is used to sample free radicals generated by thermolysis at atmospheric pressure. This is done by heating the solid sample in a custom-made probe that is fitted with a silicone membrane to allow selective and rapid introduction of the pyrolysates into the ion source of a triple quadrupole mass spectrometer. Phenyldiazonium radical (C6H5N 2 · ) and some of its ring-substituted analogs, the methoxy anilino radical CH3OC6H4NH·, and aryl radicals are generated by gas phase thermolysis of symmetrical aryl diazoamino compounds (ArNH-N2Ar). The radicals are identified by measurement of their ionization energies (IE) using threshold ionization efficiency data. A linear correlation between the ionization energy of the phenyldiazonium radicals and their Brown σ+ values is observed, and this confirms the formation of these species and validates the applicability of MIMS in sampling these radicals. The ionization energies of the aryldiazonium radicals are estimated as IE (p-CH3O-C6H4N 2 · ), 6.74 ± 0.2 eV; IE (p-CH3-C6H4N 2 · ), 7.72 ± 0.2 eV; IE (C6H5N 2 · ), 7.89 ± 0.2 eV; IE (m-Cl-C6H4N 2 · ), 7.91 ± 0.2 eV; IE (p-F-C6H 4 · N 2 · ), 8.03 ± 0.2 eV; and IE (m-NO2-C6H4N 2 · ), 8.90 = 0.2 eV. The ionization energies of the aryl radicals are estimated as IE (p-CH3O-C6H 4 · ), 7.33 ± 0.2 eV; IE (p-CH3-C6H 4 · ), 8.31 ± 0.2 eV; IE (C6H 5 · ), 8.44 ± 0.2 eV; IE (m-Cl-C6H 4 · ), 8.50 ± 0.2 eV and IE (p-F-C6H 4 · ), 8.54 ± 0.2 eV. Also, the ionization energy of the p-methoxyanilino radical (p-CH3O-C6H4NH·) is estimated as 7.63 ± 0.2 eV.  相似文献   

14.
The boiling point and volatility are important properties for fuels, as it is for quality control of the industry of petroleum diesel and biofuels. In addition, through the volatility is possible to predict properties, such as vapor pressure, density, latent heat, heat of vaporization, viscosity, and surface tension of biodiesel. From thermogravimetry analysis it is possible to find the kinetic parameters (activation energy, pre-exponential factor, and reaction order), of thermally simulated processes, like volatilization. With the kinetic parameters, it is possible to obtain the thermodynamic parameters by mathematical formula. For the kinetic parameters, the minor values of activation energy were found for mineral diesel (E = 49.38 kJ mol?1), followed by babassu biodiesel (E = 76.37 kJ mol?1), and palm biodiesel (E = 87.00 kJ mol?1). Between the two biofuels studied, the babassu biodiesel has the higher minor value of activation energy. The thermodynamics parameters of babassu biodiesel are, ΔS = ?129.12 J mol?1 K?1, ΔH = +80.38 kJ mol?1 and ΔG = +142.74 kJ mol?1. For palm biodiesel ΔS = ?119.26 J mol?1 K?1, ΔH = + 90.53 kJ mol?1 and ΔG = +141.21 kJ mol?1, and for diesel ΔS = ?131.3 J mol?1 K?1, ΔH = +53.29 kJ mol?1 and ΔG = +115.13 kJ mol?1. The kinetic thermal analysis shows that all E, ΔH, and ΔG values are positive and ΔS values are negative, consequently, all thermodynamic parameters indicate non-spontaneous processes of volatilization for all the fuels studied.  相似文献   

15.
A new class of surfactant–cobalt(III) complexes of the type trans-[Co(DH)2(OA)X], where DH = dimethylglyoxime, OA = octadecylamine, X = Cl?, Br?, I?, N3 ?, NO2 ?, SCN? or OA, were synthesized and characterized by physicochemical and spectroscopic methods. The critical micelle concentration (CMC) values of these surfactant–cobalt(III) complexes in ethanol solution were obtained by measuring absorption at ~250 nm. Specific conductivity data (at 303–313 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG m 0 , ΔH m 0 and ΔS m 0 ). Steady-state photolysis and cyclic voltammetry of the complexes were studied. The surfactant–cobalt(III) complexes were screened for their antibacterial and antifungal activities against various microorganisms.  相似文献   

16.
The thermal and kinetic studies of epoxidized natural rubber (ENR) and its polymer electrolytes, LiX/ENR PEs, (where X = ClO 4 ? , CF3SO 3 ? , COOCF 3 ? , I?, and BF 4 ? ) were carried out using thermogravimetric analysis at different heating rates. The thermal behaviors for LiX/ENR PEs are closely related to the morphology and interactions between the LiX and ENR chains. The LiCF3SO3, LiCOOCF3, and LiI form pseudo-crosslinking within the ENR; their thermal behavior resembled purified ENR. The LiClO4 tends to form aggregates within the ENR. This phenomenon has promoted a much earlier decomposition of epoxide in the ENR. The occurrence of ring-opening and complexation or cross-linking reactions in and between the ENR chains in the LiBF4/ENR has produced a thermally stable macrostructure. The activation energy for the thermal degradation (E d) of purified ENR was 239.8 and 239.9 kJ mol?1 using Kissinger and FWO methods, respectively. According to the Coats–Redfern method, the degradation mechanism of purified ENR follows the F1 type model, while the Criado method revealed that the degradation starts with F1 followed by D3 type models. The E d for LiX/ENR (X = COOCF 3 ? , CF3SO 3 ? , I?, and BF 4 ? ) PE’s obtained via the Kissinger method are 258.5, 257.0, 251.0, and 198.9 kJ mol?1, respectively, and the corresponding E d values obtained by FWO are 236.0, 223.6, 349.7, and 206.6 kJ mol?1, respectively. The degradation of ENR in these PEs followed the D3 type model. However, for LiClO4/ENR, the presence of two distinct degradations of ENR gave two E d values. These are 174.5 and 234.7 kJ mol?1 using Kissinger and 117.8 and 293.6 kJ mol?1 using FWO method. The degradation mechanism of ENR in the LiClO4/ENR PE was similar to purified ENR that is F1 followed by D3 type models.  相似文献   

17.
在无水乙醇中, 使低水合氯化稀土 (RE = Ho, Er, Tm, Yb, Lu) 与吡咯烷二硫代氨基甲酸铵 (APDC)和1,10-菲咯啉 (o–phen•H2O) 反应, 制得其三元固态配合物. 用化学分析和元素分析确定它的组成为RE(C5H8NS2)3(C12H8N2) (RE = Ho, Er, Tm, Yb, Lu). IR光谱说明RE3+ 分别与3个PDC的6个硫原子双齿配位, 同时与o–phen的2个氮原子双齿配位, 配位数为8. 用精密转动弹热量计测定了它们的恒容燃烧热△cU分别为(-16788.46 ± 7.74), (-15434.53 ± 8.28), (-15287.80 ± 7.31), (-15200.50 ± 7.22)和(-15254.34 ± 6.61) kJ•mol-1; 并计算了它们的标准摩尔燃烧焓△cHmθ和标准摩尔生成焓△fHmθ分别为( -16803.95 ± 7.74), (-15450.02 ± 8.28), (-15303.29 ± 9.28), (-15215.99 ± 7.22), (-15269.83 ± 6.61) kJ • mol-1和 (-1115.42 ± 8.94), (-2477.80 ± 9.15), (-2619.95 ± 10.44), (-2670.17 ± 8.22), (-2650.06 ± 8.49) kJ•mol-1.  相似文献   

18.
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 …  相似文献   

19.
For the first time, the heat capacity $ C_{\text{p}}^{^\circ } $ of poly(2-ethylhexyl acrylate) has been studied in an adiabatic vacuum calorimeter between 7 and 350 K, the standard thermodynamic functions: heat capacity $ C_{\text{p}}^{^\circ } $ (T), enthalpy H°(T) ? H°(0), entropy S°(T) ? S°(0), Gibbs function G°(T) ? H°(0) have been calculated from T → 0 to 350 K. The energy of combustion Δc U of the compound under study has been measured in a calorimeter with a stationary bomb and an isothermal shell. The standard enthalpy of combustion Δc H° and thermodynamic parameters of formation—enthalpy Δf H°, entropy Δf S°, Gibbs function Δf G°—at T = 298.15 K have been calculated. The results have been used to calculate the thermodynamic characteristics of 2-ethylhexyl acrylate bulk polymerization into poly(2-ethylhexyl acrylate) over the range from T → 0 to 350 K.  相似文献   

20.
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…  相似文献   

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