NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 26
·11164-11171
·
IF 3.288
Zhuo Wang,Jin Liu,Zhen Li,Xianbiao Wang,Ping Wang,Di Wang,Fengjun Zhang
A crosslinkable UIO-66 type MOF material denoted UIO-66-DETA composed of Zr(IV) metal ions and 2,5-diallyl ether terephthalic acid (DETA) was synthesized, and then by initiating double bond crosslinking, a new crosslinking MOF material denoted UIO-66-DETA-CL was obtained. UIO-66-DETA and UIO-66-DETA-CL were characterized by FTIR spectroscopy, PXRD, 1H solid-state NMR spectroscopy, SEM, nitrogen sorption, thermogravimetric analysis and hydrogen storage tests to analyze their structure and properties. The results showed that a crosslinked structure has been formed, and UIO-66-DETA-CL can maintain its structure below 340 °C, compared with UIO-66-DETA; its carbon residual rate is improved, which shows that the crosslinking modification enhances the thermal stability. Meanwhile, the hydrogen uptake capacity of UIO-66-DETA-CL reaches 5.36 wt% at 77 K and 4 MPa. Furthermore, the hydrogen adsorption enthalpy of UIO-66-DETA-CL (ΔHUIO-66-DETA-CL) calculated using the Arrhenius equation reaches −0.889 kJ mol−1, which is significantly improved by crosslinking modification. The crosslinked structure changes the pore size and increases the active adsorption sites in organic ligands. The framework of UIO-66-DETA-CL can provide more polar charges to cause some hydrogen molecules to be negatively charged because of a small HOMO–LUMO gap, and a lower LUMO energy level of UIO-66-DETA-CL enables stronger negative charge acceptability. Therefore, crosslinking modification enhances the material's hydrogen storage capacity. This result provides a new idea for the crosslinking modification of MOFs.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2024
·
IF 2
Jumei Xu,Yu Qi,Zuoxiang Zeng,Weilan Xue
The density and the heat capacity of (E,E)-methyl sorbate (MS) were measured from 286.35 to 433.25 K using a pycnometer and an adiabatic calorimeter, respectively. The saturated vapor pressure of MS was determined by the ebulliometric method from 344.95 to 455.15 K and correlated by the Antoine equation with an average relative deviation of 1.68%. The enthalpy of vaporization of MS at the normal boiling point was figured out to be 44.29 kJ mol–1 according to the Clausius–Clapeyron equation. Based on the Othmer method, the standard enthalpy of vaporization of MS was obtained using three substances as a reference, and the calculated results were further verified by the Watson relation and the Clarke–Glew equation.
研究领域:
物理化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY
·
2014
·
IF 2.227
Y.Y. Wang,X. Kang,Y.W. Liu,W.Q. Xu,L. Wang,C.Z. Hu,J. Chen,F.Y. Liu,L.S. Sheng,X.L. Zhao,P.F. Zhang,L.F. Zhu
Using vacuum ultraviolet photons produced by synchrotron radiation and reflection time-of-flight mass spectrometer, dissociative photoionization of isooctane was measured in the photon energy region of 9.7–15.6 eV under ultrasonic molecular beam. Then the dissociative ionization products at different photon energies were obtained. By measuring the photoionization efficiency curves, the appearance potentials of the dominative ion fragments and the vertical ionization energy of isooctane were determined. In addition, combining with G3 calculations we obtained the structure and energy of the parent, neutral and ion fragments. By comparing the experimental measurements with the theoretical calculations, the dissociative photoionization channels of isooctane were elucidated, and formation enthalpies of the fragmented ions and the dissociation energy of the parent ion were obtained.
研究领域:
化学物理
·
分子光谱学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2014
·
IF 2.045
Chongjun Liu,Leping Dang,Wenshuai Bai,Rui Wang,Hongyuan Wei
In this work, the thermodynamics of theophylline anhydrate and monohydrate were investigated. The solubilities of theophylline anhydrate and monohydrate in methanol–water and isopropanol–water mixtures were measured from 278.15 K to 303.15 K. Then the solubility data were correlated with the combined nearly ideal binary solvent/Redlich–Kister (CNIBS/R–K) model and the modified Jouyban–Acree model, respectively. The water activity aT that corresponds to the transformation between hydrate and anhydrate forms of theophylline was investigated. The water activity was accurately calculated by the Wilson equation and correlated by the van’t Hoff equation. The transformation enthalpy and entropy were calculated as well. The ternary phase diagrams of the theophylline–methanol–water system and theophylline–isopropanol–water system thus were obtained.
研究领域:
药学
·
物理化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2018
·
IF 2.631
Kun-Xian Wu,Xiao-Jun Zhao,Zhi-Hong Liu
Two alkali-alkaline earth metal borates with NLO properties for NaCaBO 3 and Li 4 CaB 2 O 6 have been synthesized and characterized by XRD, FT-IR, and chemical analysis. The molar enthalpies of solution of NaCaBO 3 (s) and Li 4 CaB 2 O 6 (s) in 2.00 cm 3 of 1 mol·dm −3 HCl (aq) were measured by microcalorimeter at T = 298.15 K, respectively. The molar enthalpies of solution of CaCl 2 ·2H 2 O(s) in the mixture solvent of 2.00 cm 3 of (1 mol·dm −3 HCl + H 3 BO 3 + NaCl) (aq), and {2.00 cm 3 of 1 mol·dm −3 HCl + H 3 BO 3 + LiCl·H 2 O} (aq) were also measured, respectively. With the incorporation of the previously determined enthalpies of solution of H 3 BO 3 (s) in 2.00 cm 3 of 1 mol·dm −3 HCl (aq), NaCl (s) in the mixture solvent of (2.00 cm 3 of 1 mol·dm −3 HCl + H 3 BO 3 ) (aq) and LiCl·H 2 O(s) in the mixture solvent of {2.00 cm 3 of 1 mol·dm −3 HCl + H 3 BO 3 } (aq), together with the standard molar enthalpies of formation for CaCl 2 ·2H 2 O (s), NaCl(s)/LiCl·H 2 O (s), H 3 BO 3 (s), HCl (aq) and H 2 O (l), the standard molar enthalpies of formation of – (1664.5 ± 0.9) kJ·mol −1 for NaCaBO 3 (s) and – (3391.7 ± 1.9) kJ·mol −1 for Li 4 CaB 2 O 6 (s) at T = 298.15 K were obtained on the basis of the appropriate thermochemical cycles .
研究领域:
无机化学
·
材料科学
·
物理化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2020
·
IF 2.888
Zhan-Ping Qiao,Tian Yang,Shu-Zhi Cao,Yu-Feng Tang,Qi-Chao Yang
Solid-liquid equilibria in the ternary systems RbX + CdX 2 + H 2 O (X = Cl, Br) at T = 298.15 K and under 101.3 kPa were investigated by the method of isothermal solution saturation, and the corresponding phase diagrams were constructed. It was found that there were five crystallization regions corresponding to CdCl 2 ·2.5H 2 O, RbCd 2 Cl 5 ·H 2 O, RbCdCl 3 , Rb 4 CdCl 6 and RbCl in the system (RbCl + CdCl 2 + H 2 O). Four crystallization regions corresponding to CdBr 2 ·4H 2 O, RbCdBr 3 , Rb 4 CdBr 6 and RbBr were found in the system (RbBr + CdBr 2 + H 2 O). The new solid compounds RbCdCl 3 , RbCdBr 3 and Rb 4 CdBr 6 were congruently soluble in water, and new double salts RbCd 2 Cl 5 ·H 2 O and Rb 4 CdCl 6 were incongruently soluble in water. The new solid-phase compounds RbCd 2 Cl 5 ·H 2 O, RbCdCl 3 , Rb 4 CdCl 6 , RbCdBr 3 and Rb 4 CdBr 6 were characterized by chemical analysis, XRD and TG-DTG techniques. The standard molar enthalpies of solution of RbCd 2 Cl 5 ·H 2 O, RbCdCl 3 , Rb 4 CdCl 6 , RbCdBr 3 and Rb 4 CdBr 6 in water were measured to be (20.74 ± 0.16) kJ·mol −1 , (28.00 ± 0.39) kJ·mol −1 , (96.56 ± 0.50) kJ·mol −1 , (35.38 ± 0.33) kJ·mol −1 and (110.64 ± 0.62) kJ·mol −1 by microcalorimetry in the condition of infinite dilution, and their standard molar enthalpies of formation were determined to be −(1545.3 ± 0.6) kJ·mol −1 , −(856.5 ± 0.7) kJ·mol −1 , −(2180.1 ± 1.3) kJ·mol −1 , −(727.1 ± 0.7) kJ·mol −1 and −(1920.5 ± 1.3) kJ·mol −1 , respectively.
研究领域:
物理化学
·
热力学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2021
·Vol. 39
·期 9
·1211-1216
·
IF 3.603
Xiang Ming-Yue,Lyu Dong,Liu Ling-Zhi,Men Yong-Feng
Crystallinity of bottlebrush polymers due to side chain crystallization has been considered to be related to the length of the side chains only under the assumption of complete participation of crystallization by all side chains. Recent experimental results revealed that in poly( n -alkyl methacrylate)s a fraction of side chains could not crystallize due to constraints imposed by the trapped main chain entanglements and required expansion of main chain-main chain distance. This result renders the original simplified consideration of the origin of crystallinity in bottlebrush polymers questionable. In this work, we introduce a new parameter f c , the fraction of crystallizable side chains, to better describe the crystallinity of bottlebrush polymers. A linear relationship between the melting enthalpy and the number of alkyl groups in side chains for bottlebrush polymers reported repeatedly indicates that f c remains essentially unchanged when bottlebrush polymers had the same main chain structure and grafting degree but different side chain lengths. The slope of the above-mentioned linear relationship is thus \(\Delta H_{\text{CH}_2}\times f_{c}\) , where \(\Delta H_{\text{CH}_2}\) stands for the melting enthalpy of one mole alkyl group packed into the crystal. With a known value of f c , it is possible to estimate the value of \(\Delta H_{\text{CH}_2}\) . In case of poly( n -alkyl methacrylate)s, we estimated \(\Delta H_{\text{CH}_2}\) of hexagonal crystal being at most 5.74 kJ/mol with the knowledge of possibly smallest f c of 0.67 obtained from small angle X-ray scattering data. Therefore, the crystallinity of bottlebrush polymer would be calculated based on the equation \(X_{\rm{c}}=f_{\rm{c}}\times\frac{N_{\rm{c}}}{N}\) with N and N c being the number of alkyl groups in a side chain and those packed in the crystalline structure, respectively. Both chemical structure and grafting degree of bottlebrush polymers affect f c .
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2019
·Vol. 140
·期 4
·1791-1800
·
IF 2.471
Wang Xuan,Xiao Kesong,Liu Xiangnong,Wu Hao,Gao Cai
The phenomenological models based on fictive temperature and nonlinear Adam–Gibbs formulation have been widely used to describe the enthalpy relaxation kinetics. Although the parameters in Adam–Gibbs formulation are physically explicable, the reasonabilities of the parameters obtained from curve-fitting procedures have not been systematically discussed yet. In this work, differential scanning calorimetry was employed to measure the heat capacities of maltitol in both the amorphous and the crystalline states, and the data were used to generate the model parameters. Results showed that the configurational ground state plays an important role in extracting the model parameters. Selecting the crystal rather than the glass as the ground state seems to be effective to improve the reasonabilities of the fitted parameters. It suggested that even if the fit quality seems sound, the physical reasonability of the best-fit parameters still needs to be treated with caution.
研究领域:
材料科学
·
热力学
✓ 已验证
DOI
高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2025
·
IF 3.2
Liu Yang,Liang Kaili,Zhang Keqin,Du Bowen,Hu Lishuang,Yuan Zhilei,Zhang Jianren,Lu Yuewen,Yu Qi,Lv Zhixing
The output energy properties of the AP/Ti, Cl-20/Ti, HMX/Ti, and DAP-4/Ti mixtures were compared using an oxygen bomb calorimeter. The thermal decomposition processes of the above four kinds of mixed energetic materials were studied with a differential scanning calorimeter (DSC), and the apparent activation energies of the mixed materials were calculated using the Kissinger equation. The combustion flames of the four energetic materials were captured through high-speed photography, and the combustion properties of the mixed energetic materials with titanium powders were analyzed. The results indicate that the combustion heat value of DAP-4/Ti mixed energetic materials is up to 10,133 J·g −1 , significantly higher than the 8613 J·g −1 of the Cl-20/Ti mixture and the 9720 J·g −1 of the HMX/Ti mixture. The combustion process of the DAP-4/Ti mixture only takes 145 ms. The heat release, burning rate, and flame strength of the DAP-4/Ti mixture are better than those of other mixed energetic materials. The calculated apparent activation energy of DAP-4/Ti mixture is 150.4 kJ·mol −1 , which is 55 kJ·mol −1 lower than that of DAP-4. The apparent activation energies of Cl-20/Ti and HMX/Ti are 173.6 kJ·mol −1 and 317.2 kJ·mol −1 , respectively. These findings demonstrate that DAP-4/Ti mixed energetic materials exhibit good energy characteristics and combustion performance.
研究领域:
材料科学
·
化学工程
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Pan Liang,Sa-Ying Li
The s tandard mole enthalpy of formation is an essential feature of chemical compounds, which is critical for assessing the thermal effects of chemical reactions with their participation. In this paper, two pure phases of zinc borates, 2ZnO·2B 2 O 3 ·3H 2 O and ZnB 4 O 7 , have been synthesized by hydrothermal and boric acid flux methods, respectively. They were characterized by XRD, FT-IR and TGA. The molar enthalpies of solution of 2ZnO·2B 2 O 3 ·3H 2 O (s) and ZnB 4 O 7 (s) in 1 mol·dm −3 HCl (aq) were measured at T = 298.15 K, respectively, by the use of an isothermal microcalorimeter. In accordance with Hess’ law, the standard molar enthalpies of formation of the two zinc borates 2ZnO·2B 2 O 3 ·3H 2 O (s) and ZnB 4 O 7 (s) were calculated to be −(4177.02 ± 3.3) kJ·mol −1 and −(2971.1 ± 3.3) kJ·mol −1 , respectively, by the use of standard molar enthalpies of formation for ZnO (s), H 3 BO 3 (s) and H 2 O (l) based on the two designed thermochemical cycles.
研究领域:
无机化学
·
物理化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Rongtai Yu,Jianchao Xie,Fangfen Jin,Weiwei Lu,Mingzhu Jin,Xinyang He,Ashok K. Nanjundan,Chengzhong Yu,Xiaodan Huang
Solar-driven interfacial evaporation systems hold great potential for addressing clean water scarcity and wastewater purification challenges. However, low water yield and the presence of contaminants in wastewater remain significant obstacles. This study introduces wide light-absorbing hydrophilic aminophenol–formaldehyde (APF) resin particles with π-conjugated and π-stacked benzenoid–quinoid donor–acceptor couples as light absorbers to enhance solar-to-vapor conversion efficiency. The incorporation of hydrophilic amine groups led to a 30% increase in the evaporation rate and a 32% reduction in the evaporation enthalpy. The carbonized APF-based evaporator achieved a high evaporation rate of 2.89 kg m−2 h−1 and 3.07 kg m−2 h−1 from sewage and simulated seawater, respectively, under natural solar irradiance (0.7 suns). Furthermore, solar vapor generation rates reached 16.22 kg m−2 h−1 and 13.98 kg m−2 h−1 from sewage and simulated seawater under 3.9 suns. The APF-based evaporator also demonstrated exceptional stability and durability in solar-to-vapor conversion.
研究领域:
材料科学
·
环境科学
·
能源研究
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Chunyan Ma,Yanhua Guo,Dongxue Li,Jianpeng Zong,Xiaoyan Ji,Chang Liu
The molar enthalpies of mixing were measured for binary systems of choline chloride-based deep eutectic solvents (glycerol, ethylene glycol and malonic acid) with water at 298.15 K and 308.15 K, and atmospheric pressure with an isothermal calorimeter. Refractive indices were also measured at 303.15 K and atmospheric pressure. The binary mixtures of {chcl/glycerol (1:2) + water, chcl/ethylene glycol (1:2) + water} showed exothermic behaviour over the entire range of composition, while the binary mixture of {chcl/malonic acid (1:1) + water} showed endothermic behaviour at first and then changed to be exothermic with the increasing content of chcl/malonic acid (1:1). Experimental refractive indices were fitted with the Redlich–Kister equation, and experimental molar enthalpies of mixing were correlated with the Redlich–Kister equation and the non-random two-liquid (NRTL) model. The NRTL model with the fitted parameters was used to predict the vapour pressures of these three mixtures. For mixtures of {chcl/glycerol (1:2) + water} and {chcl/ethylene glycol (1:2) + water}, the predicted vapour pressures agreed well with the experimental results from the literature. While for mixture of {chcl/malonic acid (1:1) + water}, the predicted vapour pressures showed deviation at the high concentration of chcl/malonic acid (1:1), and this was probably because of the complex molecular interaction between chcl/malonic acid (1:1) and water.
研究领域:
物理化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）