JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2018
·
IF 3.468
Jin Zong You,Cheng Jie Wu,Xue Jie Wang
Irbesartan (IBS) is an inhibitor of angiotensin II receptor. In order to study the thermal stability and the thermal decomposition mechanism of IBS, the thermal decomposition processes of IBS in nitrogen and in air atmospheres were studied by means of thermogravimetry (TG) and differential scanning calorimetry (DSC), the evolved gaseous products from thermal decomposition were identified with thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR), and the residues of thermal decomposition at various temperatures were analyzed with infrared spectra, high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC–MS). The molecular bond orders were calculated by GAMESS program of quantum chemistry, and the thermal decomposition mechanism of IBS was discussed. The results indicated that the thermal decomposition of IBS is a three-stage process and the initial temperatures of the decomposition are 204.7 and 201.0 °C in nitrogen and in air, respectively. The initial step of the decomposition is the partial decomposition of imidazolone and tetrazol sections. The thermal stability of IBS is quite good in the routine temperature.
研究领域:
药学
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分析化学
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量子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Yifan Zhang,Xianwei Hu,Fengguo Liu,Jiaxin Yang,Liyu Chen,Wenju Tao,Aimin Liu,Zhongning Shi,Zhaowen Wang
In the present study, the reaction process and reaction mechanism of the aluminothermic reduction of NaVO 3 to prepare aluminum-vanadium intermediate alloy were investigated by experimental analysis and quantum chemical calculations. The results of thermal analysis and isothermal experiments indicated that the aluminothermic reduction of NaVO 3 was a multi-step process and temperature played a critical role in this process. The aluminum-vanadium intermediate alloy was generated when the temperature exceeded 963 ºC, and it could be further separated from the reduction product after the addition of slag-forming agents (CaO and CaF 2 ) at 1600 ºC. Furthermore, an atomic-level insight into the reaction between aluminum and NaVO 3 was explored based on the electrostatic potential (ESP) analysis of the reactivity of NaVO 3 . The results showed that the aluminum atom first interacted with NaVO 3 to form an intermediate complex through electrostatic interaction , and then NaVO 3 was reduced to NaVO 2 under the continuous action of aluminum. Further, the newly formed NaVO 2 was consequently converted to aluminum-vanadium intermediate alloy under the continuous action of aluminum atoms. These theoretical results were essentially consistent with the experimental data, which provided a fundamental understanding about the reaction mechanism of NaVO 3 with Al. Moreover, the aluminothermic reduction of NaVO 3 also provided a feasible and environmentally friendly metallurgical approach for preparing aluminum-vanadium intermediate alloy.
研究领域:
冶金学
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量子化学
✓ 已验证
产品关联
DOI
高影响因子
Asia-Pacific Journal of Chemical Engineering
·
2023
·Vol. 18
·期 4
·e2908
·
IF 1.8
Tao Ge,Yuqing Wang,Jingyao Xu,Dinghao Liu,Yulu Wei,Zhaohui Wang
The microwave absorption properties of dielectrics determine the promotion degree of microwave energy to chemical reaction. The wave-absorbing characteristics of organic sulfur compounds in high-sulfur coking coal need to be studied to improve the efficiency of microwave desulfurization of coal. In this study, the imaginary part of complex dielectric constants ( ε′′ ) and dielectric loss tangent (tan σ ) of benzene mercaptan, difurfuryl disulfide, and benzothiophene were characterized. The dipole moment, molecular configuration, and frontier molecular orbital energy of organic sulfur compounds were simulated and calculated under the different external energy fields. The migration law of mercaptan, sulfide, and thiophene in coal in microwave field were analyzed. The results show that the ε'′ and tan σ of benzothiophene slightly changed with the change in microwave frequency in the frequency range of 500–2500 MHz, and the microwave absorption properties are weaker than those of benzene mercaptan and difurfuryl disulfide. Therefore, difurfuryl disulfide and benzene mercaptan molecules are more active in the microwave field than benzothiophene. The sulfur components in benzene mercaptan and difurfuryl disulfide can dissociate in the form of small inorganic sulfur molecules of carbon sulfides and disulfides, respectively. After microwave irradiation, the relative content of mercaptan and thioether in coal was decreased, whereas the relative content of thiophene remained almost unchanged.
研究领域:
能源化学
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量子化学
✓ 已验证
DOI
高影响因子
PLoS One
·
2020
·Vol. 15
·期 5
·e0232750
·
IF 2.74
Xueqing He,Pei You,Yunfu Sun
The rare earth element lanthanum (La) has been proven to be beneficial for plant growth with a low concentration, and abscisic acid (ABA) which is a plant hormone also can regulate plant growth. In the present study, we investigated the germination and seedling growth of switchgrass ( Panicum virgatum L.) under La (10 μM), ABA (10 μM) and La + ABA treatments. The results showed that La, ABA and La + ABA treatments could not significantly affect the germination and shoot length as compared to the control ( P >0.05). However, La treatment increased the root activity and chlorophyll content, and ABA treatment enhanced root length and root activity ( P <0.05). La + ABA treatments demonstrated that La could not significantly alleviate the promotion of ABA in root length, while ABA reversed the increase of chlorophyll content caused by La. The coregulation of La and ABA on chlorophyll content was further explored by in vitro experiments and quantum chemical calculations. In vitro experiments revealed that La, ABA, and La + ABA treatments reduced the absorbance of chlorophyll, and quantum chemical calculations indicated that the reduction of absorbance was caused by the reactions between La, ABA and chlorophyll. In vivo and in vitro experiments, together with quantum chemical calculations, demonstrated that both ABA and La could stimulate the production of chlorophyll, while they also could react with chlorophyll to produce La-monochlorophyll, La-bischlorophyll, and ABA adsorbed chlorophyll, which had lower absorbance. La + ABA treatment significantly decreased the chlorophyll content in vivo. This phenomenon was due to the fact that La and ABA formed LaABA compound, which markedly reduced the concentrations of ABA and La, and the effect of promoting chlorophyll production was overcome by the effect of reducing chlorophyll absorbance.
研究领域:
植物科学
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农学
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量子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2021
·
IF 5.876
Yanli Zhang,Xiaomin Qiu,Hongru Zhang,Wanxiang Zhang,Huaqing Qi,Zhaoyou Zhu,Yinglong Wang,Jingwei Yang
Background After ammoniation of propacetamol hydrochloride, the liquor contains an azeotropic mixture of acetone and diethylamine. The mixture must be separated to reuse the solvent and the raw material. However, the separation of acetone and diethylamine is difficult because the boiling point difference is only 0.6°C. Methods In this study, the mechanism of separating azeotropes was studied by quantum chemical calculations of the σ-profiles, interaction energy and molecular conformation . The vapor-liquid equilibrium data were supplemented by experimental analysis of the vapor-liquid equilibrium for cyclohexanol and diethylamine. The relative volatility of the light and heavy components of the azeotrope was investigated after adding the solvent. Sequential iteration method was used to optimize the extractive distillation process. The parameters in process such as the feeding position, number of stages and the amount of solvent are optimized, and the minimum total annual cost is obtained. Significant findings The results showed that the two-column feed preheating extractive distillation process was the lowest. The results showed that the two-column feed preheating extractive distillation process afforded the lowest total annual cost. Thermodynamic and environmental analyses showed that the two-column feed preheating extractive distillation process afforded good energy-saving, with minimal environmental impact. This study is significant for implementing the extractive distillation process for azeotrope separation and the sustainable development of acetone and diethylamine products.
研究领域:
化学工程
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环境科学
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量子化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Haiqian Zhao,Jiuyang Jia,Jiaxin Ying,Mingqi He,Zekun Sun,Xing Zhang,Zhonghua Wang,Wei Zhou
Utilizing flue gas as feedstock for CO 2 electro−reduction systems is a promising technology to address problems caused by excessive CO 2 emissions. However, the O 2 contained in the flue gas has a significant adverse effect on the CO 2 reduction. Herein, a facile strategy was proposed to suppress the influence of O 2 by constructing a CO 2 −enriched region. N−doping was demonstrated to be an efficient way to enhance CO 2 adsorption selectivity over O 2 on activated carbon. The N−doped activated carbon achieved 3.7 times increase in CO 2 adsorption selectivity over O 2 than that before modification under simulated flue gas atmosphere (75 %N 2 + 15 %CO 2 + 10 %O 2 ). The distinction in adsorption mechanism between CO 2 and O 2 was revealed by quantum chemistry study. The increased polarity of the carbon materials favored CO 2 adsorption and had less impact on O 2 adsorption. The electrostatic interaction between CO 2 and carbon material was demonstrated to be enhanced after the introduction of pyridinic N and pyrrolic N, which led to an improvement in the CO 2 adsorption capacity. The dispersion interaction, which fully regulated O 2 adsorption, was weakened due to the deviation of the O 2 adsorption position. This study provided a reference for the subsequent development of CO 2 selective adsorption materials.
研究领域:
环境科学
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材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Nature Synthesis
·
2023
·Vol. 2
·期 5
·423-429
·
IF 0
Yue Xu-Hui,Chen Wei-Xing,Yang Tao,Muñoz-Castro Alvaro,Frenking Gernot,Sun Zhong-Ming
Traditionally, a metallocene complex comprises a metal centre sandwiched between two aromatic organic ligands and such complexes have been extensively investigated. Carbon-free analogues of metallocene with homoleptic As 5 or Sb 5 ligands, however, have remained experimentally elusive, especially analogues of higher nuclearity. Here we report the synthesis and characterization of sandwich-type clusters [Pn@M 12 Pn 10 (Pn 5 ) 2 ] 4–/5– (Pn = As, Sb; M = Co, Fe), where the endohedral icosahedral cluster [Pn@M 12 ] can be regarded as a spherical-like three-dimensional coordination centre surrounded by a Pn 10 ring and two Pn 5 pentagonal caps. Quantum chemical calculations reveal that the [Pn@M 12 ] has orbitals that mimic 1S, 1P and 1D electronic shells, which can interact with the outer (Pn 5 ) 2 ring layer. These interactions occur because the frontier orbitals are dominated by the ( n − 1) d block orbitals of the metal atoms. The π 1 -As 5 orbitals interact with 1S and part of the 1P shell of the central core, while the π 2 - and π 3 -As 5 orbitals interact with the symmetry-allowed part of the 1P and 1D shells. The characteristics of this orbital interaction are analogous to those of mononuclear metallocenes.
研究领域:
无机化学
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材料科学
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理论化学
✓ 已验证
DOI
JOURNAL OF CHEMICAL THERMODYNAMICS
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2023
·
IF 2.6
Qiang Gao,Ali Farajtabar
The shake-flask technique was used to test the solubility of glyburide in mixtures of acetone + water and ethyl acetate + methanol/ethanol/isopropanol under 101.0 kPa. For a fixed temperature, the glyburide solubility positively increased with the mass fraction of acetone in the acetone + water mixture, and reached a maximum value of 8.805 × 10 −6 at 298.15 K. The solubility magnitudes reach their peak when the mass fraction of ethyl acetate in solutions containing ethyl acetate plus methanol/ethanol/isopropanol is approximately 0.3, which correspond to 5.703 × 10 −4 , 5.235 × 10 −4 and 4.307 × 10 −4 , respectively, at 298.15 K. Two models-the Jouyban-Acree and modified van't Hoff-Jouyban-Acree were employed to correlate the solutility and produced the biggest relative average deviation of 7.78 %. The local composition (solvents) around the drug molecule was investigated at 298.15 K using an inverse Kirkwood-Buff integrals. The positive preferred solvation parameters of glyburide were observed in the medium and rich compositions of methanol/ n -propanol/isopropanol/acetonitrile/PG/NMP (taken from published works)/acetone, signifying that glyburide was preferentially solvated by these solvents; while they had negative magnitudes in ethyl acetate + methanol/ethanol/isopropanol systems throughout the whole ethyl acetate compositions. The solubility of glyburide in the ten solutions was properly described by an extended Hildebrand solubility parameter approach, with relative average errors of no more than 5.32 %. In addition, the electrostatic characteristics of the basicity/acidity of glyburide molecule were highlighted with the help of quantitative study of molecular surface. Because of their lowest (-158.0 kJˑmol −1 to −136.6 kJˑmol −1 ) and largest (156.6 kJˑmol −1 to 182.8 kJˑmol −1 ) global electrostatic potentials, the > C = O and > NH groups are the main targets of electrophilic and nucleophilic assault. Visual examination of the weak interactions between glyburide and the neat solvents (methanol, ethanol, isopropanol, acetone, ethyl acetate, and water) was done using the Hirshfeld partition analysis-based independent gradient model.
研究领域:
药学
·
物理化学
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2018
·Vol. 64
·期 11
·4080-4088
·
IF 3.326
Qi Ding,Xing Cui,Guo-Hua Xu,Chao-Hong He,Ke-Jun Wu
Amlodipine is a widely used medication in treating hypertension, which is also known as a chiral compound. So far efforts have been made to obtain optically pure ( S )-amlodipine because ( R )-amlodipine has poor efficacy and is related to undesirable side effects. However, the available separation methods for amlodipine are still unsatisfactory. Recently, chiral separation has become a promising application of chiral ionic liquids (CILs), because the structural designability enables them adjustable separation efficiency for specific tasks. In this work, a high-efficient CIL-based liquid–liquid extraction system was developed for racemic amlodipine separation with the assistance of quantum chemistry calculations. Enantioselectivity up to 1.35 achieved by the novel system at 298.15 K is significantly higher than other available extraction systems. Moreover, the recycling of CIL can be easily realized by backward extraction of amlodipine, which is important for the industrial application of CILs. © 2018 American Institute of Chemical Engineers AIChE J , 64: 4080–4088, 2018
研究领域:
药物化学
·
分离科学
·
量子化学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Xianguang Zeng,Lin Zhu,Xingwen Zheng
The inhibitive effect of N-lauroyl L-lysine on the corrosion of mild steel in 0.5 M H 2 SO 4 solution was investigated by electrochemical technique, weight loss measurement, scanning electron microscope (SEM) and quantum chemical calculation. The results showed that N-lauroyl L-lysine was a moderate cathodic inhibitor for mild steel in 0.5 M H 2 SO 4 solution with its inhibition efficiency increasing with concentration, and decreasing with temperature. The adsorption of N-lauroyl L-lysine on the surface of mild steel obeyed El-Awady thermodynamic-kinetic model, and the thermodynamic and kinetic parameters, as well as quantum chemical parameters, were determined to discuss the mechanism of inhibition of N-lauroyl L-lysine on mild steel surface.
研究领域:
材料科学
·
电化学
·
量子化学
✓ 已验证
DOI
PubMed
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2025
·
IF 1.7
Ji An-Lan,Ding Rui,Liang Xuan,Liu Xiao,Zhang Yu-Chen,Wang Yu-Han,Zhang Yu-Lin,Lei Ming-Di,Zhang Yi-Wen,Fu Jie,Wang Wei-Jie,Liu Jie
The corrosion inhibition performance of purine derivatives (PR, 6N-PR, 2N6N-PR, 2N6S-PR, and 2S6S-PR) on carbon steel in 1.0 M HCl was systematically investigated through electrochemical and quantum chemical approaches. For the first time, this study elucidates the critical role of thiol substituents over amino groups in enhancing inhibition efficiency, with 2,6-dimercaptopurine (2S6S-PR) achieving an exceptional inhibition rate of 85.24% at 0.001 mol/L. Electrochemical impedance spectroscopy (EIS) and polarization analyses revealed a mixed inhibition mechanism dominated by anodic passivation, while Langmuir adsorption thermodynamics ( \(\Delta {G}_{ads}^{\theta }\) = − 38.60 kJ/mol for 2S6S-PR) indicated physico-chemical synergistic adsorption. Quantum chemical calculations demonstrated that thiol groups exhibit higher reactivity than amino groups, with the 2-position substitution significantly enhancing π-electron density and planar adsorption activity. Notably, the energy gap (ΔE = 3.25 eV for 2S6S-PR) inversely correlated with inhibition efficiency, highlighting molecular instability as a key driver for strong metal-surface interactions. A novel quantitative structure–activity relationship (QSAR) model integrating HOMO, LUMO, and dipole moment parameters exhibited remarkable alignment with experimental data (R 2 > 0.99), providing a predictive framework for designing high-performance corrosion inhibitors. These findings bridge the gap between molecular structure and macroscopic inhibition behavior, offering a transformative strategy for sustainable acid corrosion protection.
研究领域:
材料科学
·
化学工程
·
理论化学
✓ 已验证
产品关联
DOI
高影响因子
PHARMACEUTICAL RESEARCH
·
2024
·Vol. 41
·期 3
·577-593
·
IF 3.5
Mei Haoran,Wang Na,Wu Di,Rong Qi,Bai Xue,Huang Xin,Zhou Lina,Wang Ting,Hao Hongxun
Purpose Tegafur (TF) is one of the most important clinical antitumor drugs with poor water solubility, severely reducing its bioavailability. This work develops new cocrystals to improve the solubility of TF and systematically investigates the intermolecular interactions to provide new insights into the formation of cocrystal and changes in physicochemical properties. Method In this paper, two new 1:1 cocrystals of TF with 2,4 dihydroxybenzoic acid (2,4HBA) and p-nitrophenol (PNP) were synthesized. The cocrystal products were identified and characterized by various solid state analysis techniques. And the high performance liquid chromatography (HPLC) was conducted to determine the solubility and dissolution rate of TF and cocrystals. Moreover, the quantum chemistry calculations of crystal structure provided theoretical support for the results. Result Compared with pure TF, the solubility and dissolution rate of TF-2,4HBA is significantly increased in a pH 6.8 buffer at 37°C. Under accelerated storage conditions (40°C, 75% RH), all cocrystal exhibits excellent stability over 8 weeks. Hirshfeld surface (HS) analysis, atoms in molecules (AIM) analysis, interaction region indicator (IRI) analysis, molecular electrostatic potential surface (MEPS) analysis and frontier molecular orbital (HOMO–LUMO) analysis were integrated to understand the hydrogen bonding interaction more comprehensively. The simulation results are in good agreement with the experimental data. The results show that the analysis of physical and chemical properties of TF-PNP cocrystal and TF crystal by quantum chemistry method is reliable at molecular level. Conclusion These results are helpful to provide guiding methods in the cocrystal development and theoretical study of tegafur.
研究领域:
药学
·
化学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）