共查询到20条相似文献,搜索用时 15 毫秒
1.
Pet'kov V. I. Loshkarev V. N. Asabina E. A. 《Russian Journal of Applied Chemistry》2004,77(2):178-181
The heat conductivity of porous Zr3(PO4)4, NaZr2(PO4)3, CsZr2(PO4)3, and Na5Zr(PO4)3 samples was studied in the range 298-673 K. The heat conductivity coefficients of the zero-porosity phosphates under study were calculated and prospects for their application were considered. 相似文献
2.
Y. M. Dan Y. R. Zhao Y. Liu S. S. Qu 《Journal of Thermal Analysis and Calorimetry》2006,84(3):531-534
The two complexes, [Ln(Ala)2(Im)(H2O)](ClO4)3 (Ln=Pr,
Gd), were synthesized and characterized. Using a solution-reaction isoperibol
calorimeter, standard enthalpies of reaction of two reactions: LnCl3⋅6H2O(s)+2Ala(s)+Im(s)+3NaClO4(s)=[Ln(Ala)2(Im)(H2O)](ClO4)3(s)+3NaCl(s)+5H2O(l) (Ln=Pr, Gd),
at T=298.15 K, were determined to be (39.26±0.10)
and (5.33±0.12) kJ mol–1 , respectively.
Standard enthalpies of formation of the two complexes at T=298.15
K, ΔfHΘm
{[Ln(Ala)2(Im)(H2O)](ClO4)3(s)} (Ln=Pr, Gd),
were calculated as –(2424.2±3.3) and –(2443.4±3.3)
kJ mol–1 , respectively. 相似文献
3.
A. V. Markin I. A. Letyanina N. N. Smirnova V. V. Sharutin O. V. Molokova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(8):1315-1321
The temperature dependence of heat capacity C
p
° = f(T) of triphenylantimony bis(acetophenoneoximate) Ph3Sb(ONCPhMe)2 was measured for the first time in an adiabatic vacuum calorimeter in the range of 6.5–370 K and a differential scanning
calorimeter in the range of 350–463 K. The temperature, enthalpy, and entropy of fusion were determined. Treatment of low-temperature
(20 K ≤ T ≤ 50 K) heat capacity was performed on the basis of Debye’s theory of the heat capacity of solids and its multifractal model
and, as a consequence, a conclusion was drawn on the type of structure topology. Standard thermodynamic functions C
p
°(T), H°(T) — H°(0), S°(T), and G°(T) — H°(0) were calculated according to the experimental data obtained for the compound mentioned in the crystalline and liquid
states for the range of T → 0–460 K. The standard entropy of the formation of crystalline Ph3Sb(ONCPhMe)2 was determined at T = 298.15 K. 相似文献
4.
Wenshen C. Yi L. Chuanpei Z. Songsheng Q. 《Journal of Thermal Analysis and Calorimetry》2001,66(2):463-468
The solid-state coordination reaction: Nd(NO3)3·6H2O(s)+4Ala(s) → Nd(Ala)4(NO3)3·H2O(s)+5H2O(l) and Er(NO3)3·6H2O(s)+4Ala(s) → Er(Ala)4(NO3)3·H2O(s)+5H2O(l) have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products
in 2 mol L–1 HCl solvent of
these two solid-solid coordination reactions have been measured using a calorimeter. From the results and other auxiliary
quantities, the standard molar formation enthalpies of [Nd(Ala)4(NO3)3·H2O, s, 298.2 K] and[Er(Ala)4(NO3)3·H2O, s,298.2 K] at 298.2 K have been determined to be Δf
H
m
0 [Nd(Ala)4(NO3)3·H2O,s, 298.2 K]=–3867.2 kJ mol–1, and Δf
H
m
0 [Er(Ala)4(NO3)3·H2O, s, 298.2 K]=–3821.5 kJ mol–1.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Complex phosphates MxZr2.25–0.25x(PO4)3, where M=Li, Na,K, Rb or Cs and x may be an integer or fraction from 0 to 9, have been synthesized, and their structure has
been investigated. The concentration and temperature ranges of stability of the phosphate phases NaZr2(PO4)3 have been found. The influence of the method for the synthesis of these phases and of the annealing temperature on their
crystal properties is studied. It was found that the structure of NaZr2(PO4)3 [NZP] exists in the above phosphate series when 0≤x≤5 for Na and K, 0≤x≤3 for Rb, and 0≤x≤1 for Cs.
N. I. Lobachevskii Nizhnii Novgorod State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 6, pp. 1104–1113, November–December, 1996.
Translated by L. Smolina 相似文献
6.
T. G. Kulagina Ya. S. Samosudova I. A. Letyanina E. V. Sevast’yanov N. N. Smirnova L. A. Smirnova A. E. Mochalova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(5):747-751
The temperature dependence of the heat capacity C
p
o= f(T) 2 of 2-ethylhexyl acrylate was studied in an adiabatic vacuum calorimeter over the temperature range 6–350 K. Measurement
errors were mainly of 0.2%. Glass formation and vitreous state parameters were determined. An isothermic shell calorimeter
with a static bomb was used to measure the energy of combustion of 2-ethylhexyl acrylate. The experimental data were used
to calculate the standard thermodynamic functions C
p
o(T), H
o(T)-H
o(0), S
o(T)-S
o(0), and G
o(T)-H
o(0) of the compound in the vitreous and liquid states over the temperature range from T → 0 to 350 K, the standard enthalpies of combustion Δc
H
o, and the thermodynamic characteristics of formation Δf
H
o, Δf
S
o, and Δf
G
o at 298.15 K and p = 0.1 MPa. 相似文献
7.
Hua-Guang Yu Yi Liu Zhi-Cheng TanJia-Xin Dong Teng-Jun ZouXiao-Ming Huang Song-Sheng Qu 《Thermochimica Acta》2003,401(2):217-224
An on-line solution-reaction isoperibol calorimeter has been constructed. The performance of the apparatus was evaluated by measuring the molar enthalpy of solution of KCl in water at 298.15 K. The uncertainty and the inaccurary of the experimental results were within ±0.3% compared with the recommended reference data. Using the calorimeter, the molar enthalpies of reaction for the following two reactions: LaCl3·7H2O(s)+2Hhq(s)+NaAc(s)=La(hq)2Ac(s)+NaCl(s)+2HCl(g)+7H2O(l) and PrCl3·6H2O(s)+2Hhq(s)+NaAc(s)=Pr(hq)2Ac(s)+NaCl(s)+2HCl(g)+6H2O(l), were determined at T=298.15 K, as −(78.3±0.6) and −(97.3±0.5) kJ mol−l, respectively. From the above molar enthalpies of reaction and other auxiliary thermodynamic quantities, the standard molar enthalpies of formation of La(hq)2Ac and Pr(hq)2Ac, at T=298.15 K, have been derived to be −(1535.5±0.7) and −(1536.7±0.6) kJ mol−l, respectively. 相似文献
8.
Ben Cherifa A. Rogez J. Jemal M. Mathieu J. C. 《Journal of Thermal Analysis and Calorimetry》2001,63(3):689-697
Using an isoperibol calorimeter for rapid reactions and a Calsol type microcalorimeter for slow processes, are applied to
determine the enthalpies of solution of two synthetic phosphate products in nitric acid. Namely, β tricalcium phosphate Ca3(PO4)2 and the calcium hydroxyapatite Ca10 (PO4)6 (OH)2 are measured by varying pH value of the solvent. Some dissolution mechanisms are proposed for various pH values. They are
ensured by complementary reactions of solution of Ca(NO3)2, Ca(H2 PO4)2 and H3 PO4 in the same solvents. An extrapolation of solution enthalpies to pH=7 leads to the enthalpy of solution of these products
in the pure water. These values are Δsol
H °=–138.3 kJ mol–1 for Ca3 (PO4)2 and –393.6 kJ mol–1 for Ca10 (PO4)6 (OH)2 .
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
M. M. Godneva D. L. Motov M. P. Rys’kina Ya. A. Pakhomovskii 《Russian Journal of Inorganic Chemistry》2012,57(7):1033-1040
The phase formation in the system ZrO(NO3)2-H3PO4-CsF(HF)-H2O was studied at the molar ratio CsF/Zr = 1 along the sections PO 4 3? /Zr = 0.5 and 1.5 at a ZrO2 concentration in the initial solution of 2?C14 wt %. The following compounds were isolated: Cs5Zr4F21 · 3H2O, CsZr2(PO4)3 · 2HF · 2H2O, CsZrF2PO4 · H2O, CsZr2F6PO4 · 4H2O (for the first time), CsHZrF3PO4 (for the first time), Cs0.70ZrF(PO4)1.23 · nH2O, and CsHZr2F2(PO4)2.66 · nH2O. The compositions of CsZrF2PO4 · H2O, Cs0.70ZrF(PO4)1.23 · nH2O, and CsHZr2F2(PO4)2.66 · nH2O are conditional. All the compounds were characterized by crystal-optical, X-ray powder diffraction, thermal analyses, and IR spectroscopy. The formula CsHZrF3PO4 was established by energy-dispersive analysis with a LEO-1450 scanning electron microscope and an MS-46 CAMECA X-ray microanalyzer. 相似文献
10.
The heat capacity investigation of crystalline pentasodium zirconium tris(phosphate) was carried out in a vacuum adiabatic calorimeter between 7 and 340 K and in a differential scanning calorimeter of the heat bridge type between 330 and 620 K. Between 389 and 424 K, an isostructural solid-to-solid phase transition of Na5Zr(PO4)3, has been found, the nature of which is connected with a centering of off-centered zirconium atoms in octahedral sites and an occupation transfer between sodium sites in the structure. The results were used to calculate the characteristics of the phase transition and the thermodynamic functions of Na5Zr(PO4)3: the transition temperature T°trs, enthalpy of transition ΔtrsH°, entropy of transition ΔtrsS°; enthalpy H°(T)−H°(0), entropy S°(T) and Gibbs function G°(T)−H°(0) over the range from 0 to 620 K. From hydrofluoric acid solution microcalorimetry, the enthalpy of solution of Na5Zr(PO4)3 at 298.15 K has been determined and the standard enthalpy of formation has been derived. By combining the data obtained by the two techniques, the Gibbs function of formation of Na5Zr(PO4)3 at 298.15 K has been calculated. 相似文献
11.
Y. Y. Di Z. C. Tan L. W. Li S. L. Gao L. X. Sun 《Journal of Thermal Analysis and Calorimetry》2007,87(2):545-551
Low-temperature heat capacities of a solid
complex Zn(Val)SO4·H2O(s) were measured by a precision automated adiabatic
calorimeter over the temperature range between 78 and 373 K. The initial dehydration
temperature of the coordination compound was determined to be, T
D=327.05
K, by analysis of the heat-capacity curve. The experimental values of molar
heat capacities were fitted to a polynomial equation of heat capacities (C
p,m) with the reduced temperatures
(x), [x=f (T)], by least
square method. The polynomial fitted values of the molar heat capacities and
fundamental thermodynamic functions of the complex relative to the standard
reference temperature 298.15 K were given with the interval of 5 K.
Enthalpies of dissolution of the [ZnSO4·7H2O(s)+Val(s)] (Δsol
H
m,l
0)
and the Zn(Val)SO4·H2O(s) (Δsol
H
m,2
0) in 100.00 mL of 2 mol dm–3 HCl(aq) at T=298.15
K were determined to be, Δsol
H
m,l
0=(94.588±0.025) kJ mol–1 and Δsol
H
m,2
0=–(46.118±0.055)
kJ mol–1, by means of a homemade isoperibol
solution–reaction calorimeter. The standard molar enthalpy of formation
of the compound was determined as: Δf
H
m
0
(Zn(Val)SO4·H2O(s), 298.15 K)=–(1850.97±1.92) kJ mol–1,
from the enthalpies of dissolution and other auxiliary thermodynamic data
through a Hess thermochemical cycle. Furthermore, the reliability of the Hess
thermochemical cycle was verified by comparing UV/Vis spectra and the refractive
indexes of solution A (from dissolution of the [ZnSO4·7H2O(s)+Val(s)] mixture
in 2 mol dm–3 hydrochloric acid) and solution
A’ (from dissolution of the complex Zn(Val)SO4·H2O(s) in 2 mol dm–3
hydrochloric acid). 相似文献
12.
Using an on-line solution-reaction isoperibol calorimeter, the standard molar enthalpies of reaction for the general thermochemical reaction: LnCl3·6H2O(s) + 2C9H7NO(s) + CH3COONa(s) = Ln(C9H6NO)2(C2H3O2)(s) + NaCl(s) + 2HCl(g) + 6H2O(l) (Ln: Nd, Sm), were determined at T=298.15 K, as kJ mol−l, respectively. From the mentioned standard molar enthalpies of reaction and other auxiliary thermodynamic quantities, the standard molar enthalpies of formation of Ln(C9H6NO)2(C2H3O2)(s) (Ln: Nd, Sm), at T=298.15 K, have been derived to be: −(1494.7±3.3) and −(1501.5±3.4) kJ mol−l, respectively. 相似文献
13.
B.V. Lebedev A.A. Yevstropov Ye.G. Kiparisova 《The Journal of chemical thermodynamics》1981,13(12):1185-1204
The heat capacities Cpo of undercanolactone, tridecanolactone, and pentadecanolactone have been measured between 10 and 370 K in a vacuum adiabatic calorimetric cryostat within about 0.2 per cent. The temperatures and enthalpies of physical transitions have been also estimated. The enthalpies of combustion of the compounds have been measured in an isothermal calorimeter with an accuracy of 0.05 per cent. From the results the functions {H (T) ? H (0)}, So(T), and {Go(T) ? Ho(0)} have been calculated over the range 0 to 340 K, and the values of ΔHfo, ΔGfo and ΔSfo have been evaluated at T = 298.15 K. 相似文献
14.
A. V. Markin V. A. Ruchenin N. N. Smirnova E. A. Gorina S. N. Titova L. V. Kalakutskaya G. A. Domrachev 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(12):2032-2038
The temperature dependence of heat capacity C
p
o = f(T) of fullerene derivative (t-Bu)12C60 has been measured by a adiabatic vacuum calorimeter over the temperature range T = 6–350 K and by a differential scanning calorimeter over the temperature range T = 330–420 K for the first time. The low-temperature (T ≤ 50 K) dependence of the heat capacity was analyzed based on Debye’s the heat capacity theory of solids and its fractal
variant. As a consequence, the conclusion about structure heterodynamicity is given. The experimental results have been used
to calculate the standard thermodynamic functions C
p
o (T), H
o(T)−H
o(0), S
o(T) and G
o(T) − H
o(0) over the range from T → 0 to 420 K. The standard entropy of formation at 298.15 K of fullerene derivative under study was calculated. The temperature
of decomposition onset of derivative was determined by differential scanning calorimetery and thermogravimetric analysis.
The standard thermodynamic characteristics of (t-Bu)12C60 and C60 fullerite were compared. 相似文献
15.
C. Marhag D. Ben Hassen-Chehimi H. Said 《Journal of Thermal Analysis and Calorimetry》2006,86(1):249-254
The thermodynamic
exploitation of the solid–liquid equilibria in the MIPO3–Pb(PO3)2, MIPO3–Cu(PO3)2
and MIPO3–Ce(PO3)3
systems (with M
I=Li,
Na, K, Rb, Cs, Ag, Tl) is carried out using a semi-empirical equation of the
liquidus curves already used with success for similar binary systems.
The enthalpy of fusion is calculated for each pure polyphosphate on
the assumption that the liquid solution is ideal and only formed by MIPO3
and M(PO3)q entities (q=2 for Pb and Cu, q=3
for M=Ce). In the most binary systems,
a wide difference between the calculated values of the melting enthalpies
of these polyphosphates and the measured ones determined from the DTA curves,
was observed. This difference is probably due to the existence of some molecular
associations in the liquid phase. 相似文献
16.
Y. R. Zhao J. X. Dong Y. Liu S. S. Qu 《Journal of Thermal Analysis and Calorimetry》2007,90(2):565-568
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 Δf
H
mΘ {Eu(Gly)4(Im)(H2O)}(ClO4)3(s)} = = −(3396.6±2.3) kJ mol−1 and Δf
H
mΘ {Sm(Gly)4(Im)(H2O)}(ClO4)3(s)} = −(3472.7±2.3) kJ mol−1, respectively. 相似文献
17.
Kulagina T. G. Lebedev B. V. Kochetkov A. M. 《Russian Journal of General Chemistry》2001,71(9):1431-1437
Tmperature dependence of heat capacity of N-(trimethylsilyl)ethyleneimine, N-(triethylsilyl)-ethyleneimine, N-(dimethylphenylsilyl)ethyleneimine with zinc chloride was studied in the 5-340 K rangein an adiabatic vacuum calorimeter with 0.2% error. From the data obtained tge complexes thermodynamicfunctions C0
p(T), H
0(T)-H
0(0), S
0(T)-S
0(0) and G
0(T)-H
0(0) are obtained in the 0-340 K, as well as fractal dimensions D and characteristic temperatures max for the functions of gractal heat capacity of solid substances. 相似文献
18.
V. I. Pet’kov E. A. Asabina M. V. Sukhanov A. V. Markin N. N. Smirnova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(12):1960-1968
The temperature dependence of the heat capacity C p ○ = f(T) of CaNi0.5Zr1.5(PO4)3 crystalline phosphate is studied by precision adiabatic vacuum and differential scanning calorimetry over the temperature range of 7–640 K. Its standard thermodynamic functions C p ○ (T), H ○(T)-H ○(0), S ○(T), and G ○(T)-H ○(0) for the region T → 0 to 640 K and the standard entropy of formation at T = 298.15 K are calculated from the obtained experimental data. Using data on the low-temperature (30–50 K) heat capacity, the D fractal dimension of phosphate is determined and conclusions about the character of the topology of its structure have been made. The final results are compared to data from thermodynamic investigations of the structurally related crystalline phosphates Zr3(PO4)4, Ni0.5Zr2(PO4)3, and Ca0.5Zr2(PO4)3. 相似文献
19.
Lebedev B. V. Kulagina T. G. Smirnova N. N. Shifrina Z. B. Averina M. S. Rusanov A. L. 《Journal of Thermal Analysis and Calorimetry》2003,74(3):735-748
In an adiabatic vacuum calorimeter, the temperature dependence of the heat capacity C
p of phenylated polyphenylene and initial comonomer 1,4-bis(2,4,5-triphenylcyclopentadienone-3-yl)benzene was studied between
6 and 340 K with an uncertainty of about 0.2%. In a calorimeter with a static bomb and an isothermal shield their energies
of combustion DUcomb were measured. From the experimental data, the thermodynamic functions C
p
0 (T), H
0(T)-H
0(0), S
0(T)-S0(0), G
0(T)-H
0(0) were calculated from 0 to 340 K, and standard enthalpies of combustion ΔH
comb
0 and thermodynamic parameters of formation-enthalpies ΔH
f
0, entropies ΔH
f
0, Gibbs functions ΔG
f
0 - of the substances studied were estimated at T=298.15 K at standard pressure. The results were used to calculate the thermodynamic characteristics (ΔH
f
0 ,ΔS
f
0, ΔG
f
0) of phenylated polyphenylene synthesis in the range from 0 to 340 K.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
The temperature dependences of the heat capacities of crystalline tetraphenyltetrahydroxycyclotetrasiloxane, octaphenyltetrahydroxytricyclooctasiloxane, and octaphenylpentacyclosilsesquioxane and of glassy polyphenylsilsesquioxane were measured in the range 6-300 K with an adiabatic vacuum calorimeter, with an accuracy of 0.3%. From these data, the thermodynamic functions C
0
p
(T), H
0(T) - H
0(0), S
0(T) - S
0(0), and G
0(T) - H
0(0) of these substances were calculated for the range 0-300 K. The standard entropies of their formation from elements at 298.15 K,
f
S
0, and the entropies of mutual transformations of these substances in the range 0-298.15 K were calculated. 相似文献