JOURNAL OF CHEMICAL THERMODYNAMICS
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2014
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IF 2.423
Pan Liang,Qiu-Yue Kang,Lu Du,Zhi-Hong Liu
Two pure microporous materials, Rb[ZnBP 2 O 8 ] and Cs[ZnBP 2 O 8 ], have been synthesized and characterized by XRD, FT-IR, DTA-TG techniques and chemical analysis. The molar enthalpies of solution of Rb[ZnBP 2 O 8 ] and Cs[ZnBP 2 O 8 ] (s) in 3 mol · dm −3 HCl (aq), of Zn(PO 3 ) 2 (s) in (HCl + H 3 BO 3 ) (aq), and of RbCl (s)/CsCl (s) in [Zn(PO 3 ) 2 + HCl + H 3 BO 3 ] (aq) were measured by microcalorimeter at T = 298.15 K, respectively. With the incorporation of the previously determined enthalpy of solution of H 3 BO 3 (s) in 3 mol · dm −3 HCl (aq), together with the use of the standard molar enthalpies of formation for Zn(PO 3 ) 2 (s), RbCl (s)/CsCl (s), H 3 BO 3 (s), HCl (aq) and H 2 O (l), the standard molar enthalpies of formation of −(3198.5 ± 1.2) kJ · mol −1 for Rb[ZnBP 2 O 8 ] and −(3212.7 ± 1.2) kJ · mol −1 for Cs[ZnBP 2 O 8 ] at T = 298.15 K were obtained on the basis of the appropriate thermochemical cycle. In addition, the molar enthalpy of formation of −(2944.4 ± 1.2) kJ · mol −1 for [ZnBP 2 O 8 ] − has also been estimated by a group contribution method, which can be used to predict the Δ f H m θ of the other similar borophosphates. Moreover, these data have been further used to compare the thermodynamic stability of this series of borophosphates.
研究领域:
材料科学
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2015
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IF 2.037
Fang Zhang,Yaocun Tang,Long Wang,Li Xu,Guoji Liu
The solubility of 2-methylnaphthalene in different organic solvents was experimentally studied by the equilibrium method at temperatures from (278.15 to 303.15) K under atmospheric pressure. The solubility of 2-methylnaphthalene in all solvents increased with the increasing temperature. The solubility data were correlated with four thermodynamic models including the van’t Hoff equation, modified Apelblat equation, λh equation, and Wilson model. It was found that the calculated solubility with modified Apelblat equation provided a good agreement with the experimental values for the solubility behavior of 2-methylnaphthalene. The thermodynamic properties of the standard dissolution enthalpy, standard entropy, and the standard mole Gibbs free energy were evaluated based on the van’t Hoff analysis. The values of enthalpy of dissolution are positive, which indicate that the dissolution process of 2-methylnaphthalene in different organic solvents is endothermic.
研究领域:
化学
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
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2022
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IF 3.269
Jinkun Guo,Bo Jin,Shijin Chu,Rufang Peng
A different type of heat-flow calorimeter is developed to measure the energy of combustion. This calorimeter uses differential thermopile as the heat-flow sensor. The calorimeter and oxygen bomb have a special structure to ensure that the heat generated by combustion heat is slowly transferred to the thermopile, and the temperature of the outside interface of the thermopile is constant. The calorific coefficient is determined by chemical calibration, providing for the chemical calibration S =(64.806 ± 0.029) μV mW −1 , which means uncertainty is 0.05 % for calibration. The combustion enthalpies of anthracene and naphthalene are measured by using this calorimeter, and the results agree with the literature values or recommended values.
研究领域:
热化学
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分析化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
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2012
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IF 2.422
Yang Lv,Ning Li,Mei Tang,Zhi-Hong Liu
Two pure hydrated aluminoborates with microporous structure, K 2 [Al(B 5 O 10 )] · 4H 2 O and (NH 4 ) 2 [Al(B 5 O 10 )] · 4H 2 O, have been synthesized and characterized by XRD, FT-IR, DTA-TG techniques and chemical analysis. The molar enthalpies of solution of K 2 [Al(B 5 O 10 )] · 4H 2 O (s) and (NH 4 ) 2 [Al(B 5 O 10 )] · 4H 2 O (s) in 1 mol · dm −3 HCl (aq) were measured to be −(88.65 ± 0.25) kJ · mol −1 and −(93.37 ± 0.25) kJ · mol −1 , respectively. The molar enthalpies of solution of AlCl 3 ·6H 2 O (s) in (HCl + H 3 BO 3 + KCl) (aq) and in (HCl + H 3 BO 3 + NH 4 Cl) (aq) were measured, respectively. With the incorporation of the previously determined enthalpy of solution of H 3 BO 3 (s) in 1 mol · dm −3 HCl (aq), together with the use of the standard molar enthalpies of formation for AlCl 3 ·6H 2 O (s), KCl (s)/NH 4 Cl (s), H 3 BO 3 (s), HCl (aq), and H 2 O (l), the standard molar enthalpy of formation of −(6029.8 ± 4.1) kJ · mol −1 for K 2 [Al(B 5 O 10 )] · 4H 2 O (s) and −(5775.0 ± 4.1) kJ · mol −1 for (NH 4 ) 2 [Al(B 5 O 10 )] · 4H 2 O (s) at T = 298.15 K were obtained on the basis of the appropriate thermochemical cycles. Moreover, Δ f H m o ([Al(B 5 O 10 )] 2− ) of −4355.3 kJ · mol −1 has also been estimated by a group contribution method, which can be used to predict the standard molar enthalpies of formation of other aluminoborates containing [Al(B 5 O 10 )] 2− anionic framework.
研究领域:
材料科学
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物理化学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2013
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IF 2.39
Pei Pei Yuan,Bin Hong Liu,He Peng Zhu,Wei Yuan Pan,Zhou Peng Li
In this work, the composites of LiBH 4 and AlF 3 were prepared and their hydrogen storage properties were investigated. The AlF 3 addition to LiBH 4 resulted in significant decreases in dehydrogenation temperature. All the x LiBH 4 + AlF 3 ( x = 1, 2, 3, 5) composites started to release hydrogen from about 100 °C. The dehydrogenation of the composites was accomplished through several steps, depending on the molar ratio of LiBH 4 to AlF 3 . A new phase Li 3 AlF 6 was formed during the first dehydrogenation step, which further reacted with LiBH 4 . AlB 2 was formed only at temperatures higher than 300 °C. Li 2 B 12 H 12 was detected as an intermediate. The dehydrogenation reactions have significantly reduced and thus favorable enthalpy changes. However, the reversibility of the composites needs to be improved.
研究领域:
材料科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2015
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IF 2.037
Rongrong Li,Jian Wan,Yingjie Zhang,Danxia Liang,Bin Zhang,Chenghong Li
The equilibrium solubility of sodium 1-naphthalenesulfonate in binary NaCl + water, Na2SO4 + water, and C2H5OH + water solvent mixtures was measured by a steady-state method at elevated temperatures from (278.15 to 323.15) K. The results of these data were correlated by a modified Apelblat equation. The dissolution enthalpy (ΔHd) and entropy (ΔSd) of sodium 1-naphthalenesulfonate in solutions of different mole fraction were obtained.
研究领域:
物理化学
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热力学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED MATERIALS
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2023
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IF 29.4
Haiming Chen,Zaizheng Sun,Kai Lu,Jinming Liu,Chaobin He,Dongsheng Mao
The mechanism behind the resilience of polymeric materials, typically attributed to the well-established entropy elasticity, often ignores the contribution of enthalpy variation (Δ H ), because it is based on the assumption of an ideal chain. However, this model does not fully account for the reduced resilience of thermoplastic polyurethane (TPU) during long-range deformation, which is mainly caused by the dynamics of physical crosslink networks. Such reduction is undesirable for long-range stretchable TPU considering its wide application range. Therefore, a negative Δ H effect is established in this work to facilitate instant recovery in long-range stretchable TPU, achieved by constructing a reversible interim interface via strain-induced phase separation. Consequently, the newly constructed dual soft segmental TPU shows resilience efficiency exceeding 95%, surpassing many synthetic high-performance TPUs with typical efficiencies below 80%, and comparable to biomaterials. Moreover, a remarkable hysteresis loop with a ratio exceeding 50%, makes it a viable candidate for applications such as artificial ligaments or buffer belts. The research also clarifies structural factors influencing resilience, including the symmetry of the dual soft segments and the content of hard segments, offering valuable insights for the design of highly resilient long-range stretchable elastomers.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
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2013
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IF 2.297
Qing Song,Qiu-Yue Kang,Sa-Ying Li,Qiu-Yan Yu,Zhi-Hong Liu
Three isotypic polyborate cluster compounds for Na 5 [AlB 24 O 34 (OH) 12 ]·5.5H 2 O, Na 5 [CrB 24 O 34 (OH) 12 ]·5H 2 O and Na 5 [GaB 24 O 34 (OH) 12 ]·3H 2 O have been synthesized and characterized by EDS, XRD, FT-IR, TG techniques and chemical analysis. The molar enthalpies of solution of Na 5 [AlB 24 O 34 (OH) 12 ]·5.5H 2 O (s) and Na 5 [CrB 24 O 34 (OH) 12 ]·5H 2 O (s) in 1 mol · dm −3 HCl (aq) were measured to be (58.27 ± 0.15) kJ · mol −1 and (130.99 ± 0.33) kJ · mol −1 , respectively. The molar enthalpies of solution of AlCl 3 ·6H 2 O (s) and CrCl 3 ·6H 2 O (s) in (HCl + H 3 BO 3 + NaCl) (aq) were also measured, respectively. With the incorporation of the previously determined enthalpy of solution of H 3 BO 3 (s) in 1 mol · dm −3 HCl (aq), together with the standard molar enthalpies of formation for AlCl 3 ·6H 2 O (s)/CrCl 3 ·6H 2 O (s), NaCl(s), H 3 BO 3 (s), HCl (aq) and H 2 O (l), the standard molar enthalpies of formation of −(21316.0 ± 19.3) kJ · mol −1 for Na 5 [CrB 24 O 34 (OH) 12 ]·5H 2 O (s) and −(21669.7 ± 19.3) kJ · mol −1 for Na 5 [AlB 24 O 34 (OH) 12 ]·5.5H 2 O (s) at T = 298.15 K were obtained on the basis of the appropriate thermochemical cycles. The molar enthalpy of formation of Na 5 [GaB 24 O 34 (OH) 12 )]·3H 2 O was estimated as −20662.9 kJ · mol −1 by using a group contribution method on the basis of these measured results.
研究领域:
无机化学
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物理化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
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2016
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IF 2.196
Guangyue Bai,Jianhui Sheng,Yujie Wang,Hui Wu,Yang Zhao,Kelei Zhuo,Margarida Bastos
The thermodynamics of molecular self-assembling of an anionic biosurfactant, sodium cholate (NaCA) and its mixtures with sodium dodecyl sulfate (SDS) in aqueous solution have been investigated by isothermal titration calorimetry (ITC), along with fluorescence and conductivity measurements. Different critical concentrations were obtained by these three techniques – critical pre-micelle concentration (cmc pre ) and critical micelle concentration (cmc) for pure NaCA, and critical micelle concentrations (cmc mix ) for the mixed systems with differently initial SDS concentrations. Importantly, ITC allowed us to directly measure the enthalpy changes of pre-micelle formation (Δ H premic = (−0.28 ± 0.02) kJ·mol −1 ) and of micelle formation (Δ H mic = (−1.76 ± 0.05) kJ·mol −1 ) for pure NaCA as well as the enthalpies for micellization for the mixed systems NaCA/SDS. The non-ideality of the mixed surfactant solution was evaluated in terms of interaction parameters and excess enthalpies that were calculated in the light of Clint’s and Rubingh’s models. It was found that there is an obvious synergistic effect in the NaCA/SDS mixed system. From all these results we can ascribe the strong interaction between the same charge surfactants NaCA and SDS to the structural difference in their hydrophobic moieties. In fact, the flexible alkyl chains of SDS and the non-planar hydrophobic β -faces of NaCA tend to have a more compact packing than pure NaCA.
研究领域:
生物化学
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2018
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IF 2.196
Heng Ban,Teng Pan,Youwei Cheng,Lijun Wang,Xi Li
The solubilities of 2,5-furandicarboxylic acid (FDCA) in binary acetic acid + water, methanol + water, and ethanol + water solvent mixtures were measured by a static analytical method with the mass fraction of water in the solvent varying from 0 to 0.3 at atmospheric pressure. Furthermore, the molar enthalpy of fusion (ΔfusH = 55.131 kJ/mol) and fusion temperature (Tfus = 614.45 K) of FDCA were determined by differential scanning calorimetry. The non-random two liquid (NRTL) model and the measured parameters were used to correlate these solubility data, and the relevant parameters were regressed by the least-squares method. The NRTL model was found to provide a satisfactory representation of the experimental data.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
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2022
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IF 6.057
Yu-Pei Tian,Tianyu Wu,Xiaoyu Meng,Hai-Mu Ye
Thermodynamic features of extended-chain crystals (ECCs) are the basis for determining crystallization driving force of polymers. However, accurate determination of melting points (Tm0) and enthalpy of fusion (ΔHm0) of ECCs is still a challenge due to the lack of corresponding physically fabricated structures, especially for a copolymer whose ECC has not been prepared or reported yet. Herein, we choose poly(butylene succinate) (PBS) and its random copolymers with adipic acid (PBSA) as model polymers and successfully fabricate their ECCs through a preparation pathway by forming inclusion complexes with urea. Consequently, the values of Tm0 and ΔHm0 have been directly determined, which are quite different from those extrapolated in previous literature. The Tm0 and ΔHm0 of PBS are respectively identified as 136 °C and 133.5 J/g. With the increase of cocrystallized butylene adipate (BA) units in the lattice, the as-measured Tm0 of the ECC declines more significantly than the extrapolated value by the Hoffman–Weeks equation based on a mismatched crystalline structure. The ΔHm0 of PBSA displays an almost linear downward dependence on BA composition, explicitly revealing a defect Gibbs free energy of 0.7 kJ/mol for the cocrystallization of BA units in PBS lattices. Our work sheds light on the accurate determination of properties of polymer ECCs and is essential to expand the understanding of ECCs from homopolymers to copolymers.
研究领域:
高分子科学
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热力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2021
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IF 2.694
JinTao He,XueMan Xu,Xia Gui
New phase equilibrium data of CO2 in n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-eicosane were measured at temperatures from 333.15 to 373.15 K up to 23.73 MPa by a constant-volume method. Thermodynamic properties of Gibbs free energy (ΔsolG), enthalpy change (ΔsolH), entropy change (ΔsolS), and Henry’s coefficient (H) were calculated and analyzed for elucidating the dissolution mechanism of CO2 in alkanes. Results showed that the CO2 solubility increased with increasing pressure but decreased with increasing temperature and carbon number. In addition, increasing carbon number also led to an increase in the minimum miscibility pressure (MMP) of alkanes with CO2 and thus limited CO2 solubility in alkanes.
研究领域:
化学热力学
·
石油工程
✓ 已验证
DOI
高影响因子
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