FLUID PHASE EQUILIBRIA
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2013
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IF 2.379
Zhongbin Meng,Yonghong Hu,Yumei Kai,Wenge Yang,Zheng Cao,Fei Shen
The solubility of thiomalic acid was measured in methanol, ethanol, 2-propanol, 1-butanol, acetone, acetonitrile, and ethyl acetate in the temperature range between 278.15 K and 333.15 K under atmospheric pressure by gravimetric method. The solubility of thiomalic acid in those selected solvents increased with increasing temperature. The solubility data were correlated using the simplified molecular thermodynamic equation, the modified Apelblat equation and the semi-empirical Buchowski–Ksiazczak λh equation. The thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were calculated by the van’t Hoff analysis and the Gibbs equation. The experimental results showed that acetonitrile had the potential as the better solvent in the recrystallization process of thiomalic acid.
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高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2023
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IF 2.6
Xudong Yu,Xia Feng,Shan Feng,Yun Peng,Ying Zeng
The solid–liquid equilibria of the quinary system Li+, K+, Mg2+//Cl–, B4O72––H2O at 323.2 K were investigated by the isothermal dissolution method. The solubility, refractive index, and density of the system were determined, and the corresponding space phase diagram, planar projection diagram, water content diagram, and density/refractive index vs composition diagrams saturated with MgB4O7 are constructed based on the experimental data. The result shows that there are double salts of lithium carnallite (LiCl·MgCl2·7H2O) and carnallite (KCl·MgCl2·6H2O) formed in the system. The space phase diagram consists of five invariant points, 16 isothermal solution curves, and eight crystalline regions (Li2B4O7·3H2O, K2B4O7·4H2O, KCl, MgB4O7·9H2O, KCl·MgCl2·6H2O, MgCl2·6H2O, LiCl·MgCl2·7H2O, LiCl·H2O). Under the saturation of salt MgB4O7, the crystalline region of Li2B4O7·3H2O is the largest in the planar projection diagram of this system, and the solubility of LiCl is the largest. A comparison of planar projection diagrams (under the saturation of salt MgB4O7) of the system at 273.2 and 323.2 K shows that the crystallization regions of Li2B4O7·3H2O, KCl·MgCl2·6H2O, LiCl·MgCl2·7H2O, and LiCl·H2O increase along with the temperature, while those of K2B4O7·4H2O and KCl decrease. The results show that low temperature is conducive to the extraction of potassium in the form of K2B4O7·4H2O and KCl and has less entrainment loss; high temperature is beneficial to the precipitation of Li2B4O7·3H2O.
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高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2022
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IF 3.119
Yongjun Wu,Yong Xie,Hongwei Shi
In this work, the mole fraction solubility of rhein in 12 pure solvents including methanol, ethanol, n-propanol, isopropyl alcohol, 1-butanol, isobutyl alcohol, 1,4-dioxane, 2-butanone, cyclohexanone, acetone, acetonitrile, and N,N-dimethylformamide (DMF) at the temperature range from 283.15 K to 323.15 K was studied. The largest mole fraction solubility is observed in 1,4-dioxane (1.450 × 10–3) at 323.15 K, followed by in DMF (6.964 × 10–4), cyclohexanone (4.026 × 10–4), acetone (2.432 × 10–4), 2-butanone (2.009 × 10–4), 1-butanol (5.646 × 10–5), isopropyl alcohol (5.082 × 10–5), n-propanol (4.552 × 10–5), isobutyl alcohol (3.375 × 10–5), ethanol (3.798 × 10–5), methanol (3.083 × 10–5), and acetonitrile (1.655 × 10–5). The solubility first increases and then decreases with the increase of carbon chain length in alcohols. Through the analysis of 1,4-dioxane and DMF properties, the solute molecules should belong to weakly polar compounds, which is also reflected in the alcohols. However, for ketone solvents, the solubility decreases with the decrease of dipolarity/polarizability. This may be caused by the joint action of the solvent cavity term effect and hydrogen bonds. The largest relative average deviation (RAD) from the data is no more than 5%, which suggests that the calculated solubility data using the modified Apelblat model and λh model agreed very well with the experimental ones for each solvent. Compared with the values reported by Cheng and co-workers, there is an increase of 87.61-fold of solubility between 1,4-dioxane and acetonitrile at 323.15 K. Hence, the solubility data achieved in the present work could be very useful for the purification and crystallization of rhein.
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高影响因子
CERAMICS INTERNATIONAL
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2024
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IF 5.1
Qinghai Sun,Zhibo Zheng,Xiaolu Yang,Yanxia Zhao,Zhou Luo,Chao Wang,Yanhua Song,Haifeng Zou,Shihou Sheng
Herein, a variety of single-phase full-spectrum emission phosphors doped with Eu 2+ were synthesized. Under the 350 nm excitation, as K + and Y 3+ were introduced into Ca 10 Na(PO 4 ) 7 (CNP):1.5%Eu 2+ , respectively, the emission color of Ca 9.85 K y Na (1- y ) ( PO 4 ) 7 :1.5%Eu 2+ (0 ≤ y ≤ 1.0) was tuned from yellow to cyan, while that of Ca (9.85- z ) NaY 0.667 z (PO 4 ) 7 :1.5%Eu 2+ (0 ≤ z ≤ 1.0) was tuned from yellow to green. The internal quantum yield (QY) of Ca 9·85 K 0·4 Na 0·6 (PO 4 ) 7 (CKNP):1.5%Eu 2+ and Ca 9·45 NaY 0·267 (PO 4 ) 7 (CNYP):1.5%Eu 2+ reached 47.47 % and 27.11 %, respectively. The introduction of K + or Y 3+ made Eu 2+ selectively occupy the Ca sites and led to changes in the local environment of Eu 2+ , allowing for spectral tuning emission. In addition, the luminescence intensity of the samples retained 54.59 % and 31.34 % of their room temperature values. Eventually, two white light emitting diode (WLED) devices were fabricated, combining the synthesized white emitting phosphors with 365 nm ultraviolet (UV) chips. They exhibited high color rendering indices of 84.7 and 77.0, along with low correlated color temperatures of 5435 K and 5023 K. The Commission Internationale de L'Eclairage (CIE) color coordinates were (0.3349, 0.3975) and (0.3517, 0.4366), respectively. The results pointed to the phosphors' potential suitability for use in the WLED sector.
研究领域:
材料科学
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光学工程
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DOI
高影响因子
CHEMOSPHERE
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2020
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IF 5.778
Jie Wang,Haibao Liu,Defang Ma,Yan Wang,Guangping Yao,Qinyan Yue,Baoyu Gao,Shue Wang,Xing Xu
In this work, the combined ultraviolet ozone process (UV/O 3 ) was applied for organic contaminant (Reactive Blue K-GL, RB) degradation in high salinity . The degradation rates of RB in both O 3 and UV/O 3 systems were enhanced by NaCl (the k increased from 0.080 to 0.116 to 0.132 and 0.267 min −1 respectively), while mineralization rate varied at different salt conditions. In addition, UV irradiation promoted the degradation efficiency of RB with the presence of salt. Singlet oxygen ( 1 O 2 ) was the primary active species in the UV/O 3 system. The quenching experiments and signal intensity of 1 O 2 corresponded well to the mineralization of RB. Under conditions of high salinity and high pH, O 3 has high mass transfer coefficient (k La , 3.303 min −1 ) and self-decomposition (k d , 0.600 min −1 ), which further promoted the formation of 1 O 2 for mineralization of RB. Furthermore, UV/O 3 system was efficient in real textile wastewater treatment (COD Cr removal rate 91.7% and decolorization rate 98.7%).
研究领域:
环境科学
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水处理
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污染物降解
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DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2021
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IF 2.694
Kangling Yin,Li Chen,Feng Liu,Taotao Fan,Zongcheng Yan
Aiming at developing more biocompatible and economic separation platforms, aqueous biphasic systems (ABS) composed of deep eutectic solvents (DES) and tert-butanol were proposed for the first time. The effects of key factors such as the hydrogen-bond donor (HBD) properties and temperature on the phase-forming ability of DES/tert-butanol ABS were investigated. Meanwhile, syringic acid and eugenol mixtures were selected as model biomolecules to evaluate the efficiency of DES/tert-butanol ABS to use as liquid–liquid extraction systems. The results indicated that DES components migrated preferentially to the bottom phase while tert-butanol was concentrated in the top phase. The more hydrophilic HBD or lower temperature was responsible for greater efficiency to induce the formation of DES/tert-butanol ABS. The reason for phase separation was the incompatibility of the hydrogen-bond acceptor (HBA) and HBD with tert-butanol in aqueous solution, where the higher hydrophilic HBD enriched favorably in the lower phase, allowing for the formation of the DES/tert-butanol ABS. The selective separation of syringic acid and eugenol was a consequence of the HBD characters, temperature, and tie-lines length of the ABS, and they could be greatly separated by using the ABS composed of betaine-xylitol (DES) and tert-butanol at 298.15 K. The highest extraction efficiency of syringic acid and eugenol was 91.64 and 97.62%, respectively. Further, syringic acid and eugenol as well as DES can be recovered and reused by using water as the antisolvent and the vacuum distillation method. This study may be expected to lay a solid foundation for the expansion of DES-based ABS and selective separation of similar biomolecules.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2014
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IF 2.045
Xia Gui,Wei Wang,ChenWei Wang,Ling Zhang,Zhi Yun,Zhg Tang
The solubility of CO2 in polyethylene glycol dimethyl ether (NHD), octamethyl cyclotetrasiloxane (D4), and diethyl succinate (DS) was determined at the temperature variations from 285.19 K to 313.26 K up to 6 MPa by the constant-volume method. Then, Henry’s law constant (H) based on mole fraction was obtained by linear fitting of the vapor–liquid phase equilibrium data, and some thermodynamic properties of solutions were also calculated from the correlation of H. The values of H in NHD, D4, and DS vary from 2.5 MPa to 8 MPa and increase in the following order: DS < D4 < NHD, which is identical to the order of the solvents ability to dissolve CO2. Additionally, Henry’s law constant increases with temperature increase to confirm the solubility of CO2 decrease in the corresponding solvents for the pressure range studied.
研究领域:
化学工程
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热力学
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高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2022
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IF 3.119
Li-Rong Guo,Guo-Liang Nie,Rui-Zhi Cui,Wu Li,Yong-Ming Zhang
In addition to the common sodium salt, potassium salt, magnesium salt, and sulfate, salt lake brine is also rich in trace components in varying degrees, such as lithium, bromine, rubidium, cesium, and so forth, which is of great industrial value. These trace components are further concentrated and enriched in old brine during the process of evaporation and concentration of brine resources. In view of the coexistence characteristics of lithium, potassium, bromine, and other ions in old halide, the phase equilibria of quinary system Li+, Na+, K+/Br–, and SO42––H2O were studied by the isothermal dissolution equilibrium method at 298.15 K. The solubility data of the equilibrium liquid phase were measured, and the compositions of the solid phase as well as the crystal forms of the equilibrium solid phase were identified when the equilibrium was achieved. The corresponding 3D and dry-base phase diagrams (Na2SO4·10H2O, K2SO4, LiBr·2H2O, Li2SO4·H2O, KBr, and NaBr·2H2O saturated) were drawn based on the phase equilibrium experimental data. The research results of phase equilibria and phase diagrams reveal that the phase relations and crystallization–dissolution law of each component in solution lay a certain foundation for further research on multi-temperature phase equilibrium and thermodynamic properties of the high-component brine system and to provide basic thermodynamic data for guiding the rational development and comprehensive utilization of brine resources.
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BIOORGANIC CHEMISTRY
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2020
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IF 4.831
Liang Yan,Yongqi Ke,Yuhe Kan,Dao Lin,Jingkui Yang,Yujian He,Li Wu
The isomerization of l -amino acids in peptides and proteins into d -configuration under physiological conditions would affect the physiological dysfunction and caused protein conformational diseases. The presence of d -amino acids might change the higher-order structure of proteins and triggered abnormal aggregation. In order to better understand this phenomenon and promote degradation, we systematically studied the enzymatic hydrolysis of a series of peptides obtained by replacing l -amino acids in different positions of template peptide KYNETWRSED with d -amino acids under the action of Protease K. The results showed that, compared with normal peptide, isomerization of different amino acids had different effects on the anti-enzymatic hydrolysis of the peptides, especially d -tryptophan at position 6, which significantly inhibited enzymatic hydrolysis. The analysis of the peptide cleavage site revealed that the efficiency of enzymatic hydrolysis mainly depended on the isomerization of the amino acids at a specific site of the peptide cleavage. Further studies showed that the enzymatic hydrolysis of substrates could be facilitated by optimized reaction conditions such as temperature, pH, addition of metal ions, and change of buffer. In this way the accumulation of disease-associated d -amino acid containing polypeptides/proteins could be prevented.
研究领域:
生物化学
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分子生物学
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蛋白质化学
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PubMed
高影响因子
Food Bioscience
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2025
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IF 5.9
Cuiting Yang,Yingying Zhang,Mingyue Jia,Qingsong Qu,Zhixun Li,Qing Zhou,Minfang Feng,Yuting Tian,Weishuo Ren,Xinyuan Shi
Monascus fermented Ginseng exhibits superior lipid-regulation activity compared to the raw materials, which undoubtedly related to fermentation-induced changes. This study aims to elucidate the interactions between Monascus purpureus (M. purpureus) and ginseng during fermentation and identify an effective ginseng fraction optimal for co-fermentation. Initially, the effective fractions extracted from ginseng—total polysaccharides, amino acids, and ginsenosides, were separately added to the basic medium to assess their impact on M. purpureus growth and metabolism. Meanwhile, ginsenoside transformation during fermentation was also investigated. The fermentation product derived from the selected ginseng fraction and M. purpureus was assessed for its lipid-lowering efficacy. The results indicated that total amino acids and total ginsenosides, except for total polysaccharides, facilitated the growth of M. purpureus and enhanced Monacolin K production. The expression levels of genes associated with M. purpureus metabolism exhibited significant alterations. The changes in various ginsenoside monomers revealed potential ginsenoside transformation pathways during the fermentation process. Additionally, Monascus purpureus fermented Ginsenosides exhibited lipid-lowering efficacy comparable to Monascus fermented Ginseng, potentially regulating the lipid metabolism via the Peroxisome proliferator-activated receptor and Sterol regulatory element-binding protein (PPAR/SREBP) signaling pathway. These insights not only elucidate the interaction mechanisms between M. purpureus and ginseng fractions during fermentation but also demonstrate the lipid-lowering potential of Monascus purpureus fermented Ginsenosides at both cellular and molecular levels, highlighting certain significance for the rational utilization of ginseng resources, revealing the key role of microorganisms in the fermentation process.
研究领域:
微生物学
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药理学
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代谢生物学
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高影响因子
BIOORGANIC CHEMISTRY
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2025
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IF 4.7
Shuaishuai Cui,Cunxin Guo,Liang Yan,Yujian He,Li Wu
The incorporation of D-amino acids can influence the structure and enzymatic stability of proteins or peptides, especially when they are introduced at enzyme cleavage sites, significantly inhibiting the enzymatic hydrolysis of peptides. The abnormal accumulation of these peptides has been linked to age-related conditions, including cataracts and Alzheimer's disease. N-terminal acetylation, an essential post-translational modification, significantly enhances the physicochemical properties of peptides and plays an essential role in regulating their performance within biological systems. This research examined the impact of N-terminal acetylation on the enzymatic hydrolysis of peptides incorporating D-amino acids. Enzymatic activity assessments showed that N-terminal acetylation greatly promoted the enzymatic breakdown of these peptides by Proteinase K (PROK), with the substrate decay rate constant for the acetylated peptide Ac-6-w increasing by 17.5 times. This enhancement was specific to serine-type proteases, which exhibited a comparable cleavage pattern. Molecular docking further demonstrated that N-terminal acetylation improved interactions within the catalytic triad of serine proteases, leading to faster enzymatic degradation. The results provide novel insights into the impact of N-terminal acetylation on the enzymatic behavior of peptides incorporating D-amino acids, and they propose a potential approach for targeting these peptides to preserve normal physiological functions.
研究领域:
生物化学
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医学
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分子生物学
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DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
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2021
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IF 3.178
Yuqi Su,Taotao Zhan,Xiangyang Liu,Maogang He,Ying Zhang
The mutual diffusion coefficients of (isooctane + n-heptane) and (n-decane + n-heptane) binary solutions were measured over the mass fraction from 0.05 to 0.95 at the pressure of 0.101 MPa, and at temperatures T = 288.15 K, 298.15 K, 308.15 K and 318.15 K, respectively. The expanded relative uncertainty of the digital holographic interferometry employed in this measurement was estimated to be 2.6% with the confidence level of 0.95 ( k = 2). The influences of temperature and composition on the mutual diffusion coefficients were discussed. Moreover, the semi-empirical correlations of mutual diffusion coefficients for (isooctane + n-heptane) and (n-decane + n-heptane) binary mixtures were given by fitting the experimental results as a function of temperature and mass fraction. The absolute average of relative deviations of the correlations are 0.72% for (isooctane + n-heptane) and 0.54% for (n-decane + n-heptane), respectively.
研究领域:
化学
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物理化学
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高影响因子
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