JOURNAL OF SOLUTION CHEMISTRY
·
2017
·Vol. 46
·期 9
·1767-1777
·
IF 1.342
Guo Lijiang,Wang Yaxiao,Tu Lanying,Li Jianqiang
Water activities for the MgCl 2 –RbCl–H 2 O ternary system and its sub-binary MgCl 2 –H 2 O and RbCl–H 2 O systems at 298.15 K have been measured using the isopiestic method. The measured results for the binary systems agree well with literature data. The measured equal water activity lines for the MgCl 2 –RbCl–H 2 O ternary system deviate from Zdanovskii’s rule. The solubilities for the MgCl 2 –RbCl–H 2 O ternary system also have been measured using a isothermal visual first/last crystal method, and the results are consistent with one reported set of solubility data. Pitzer’s model was selected to correlate the measured water activity and solubility data and the parameters reported in the literature are re-examined by comparing the model-calculated equal water activity lines and solubilities with experimental values measured in this work. New and reasonable parameters are obtained by fitting the water activity and solubility data measured in this work and those reported in the literature. The water activities and solubilities were simulated with the new parameters and the results show that the Pitzer model can successfully represent the thermodynamic properties and be used to calculate the solubility isotherms.
研究领域:
化学热力学
·
物理化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
·
IF 2.206
Chongjun Liu,Leping Dang,Yao Tong,Hongyuan Wei
In this paper, the influence of polymorphs on the transformation water activity that corresponds to the transformation between hydrate and anhydrate of theophylline was investigated. Theophylline is known to exist either as anhydrates or a monohydrate. The transformation water activities of theophylline form II and IV were determined respectively, and the solubility data of these two forms in methanol, ethanol, acetonitrile, and acetone was also determined. The following thermodynamic derivation indicates that the transformation water activity ratio of theophylline forms II to IV can be correlated with the solubility ratio. According to the above study, the stability and intercoversion of theophylline polymorphs is discussed. This work will be useful in understanding the transformation process and benificial for industrial process control.
研究领域:
药学
·
物理化学
✓ 已验证
DOI
高影响因子
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY
·
2023
·Vol. 67
·期 1
·S78
·
IF 2.1
Han H. J.,Ma J. J.,Xing K. Q.,Shao D. X.,Zhong S. K.
Abstract In this work, the equal-water activities for the ternary system LiCl−KCl−H 2 O and its sub-binary systems LiCl−H 2 O were determined using an isopiestic method at 323.15 K. The determined isopiestic composition lines for the LiCl−KCl−H 2 O system were found to deviated Zdanovskii rule high with increasing ionic strength of the mixture solution. The addition of KCl to an aqueous solution of LiCl was found to decrease and increase the water activity at low and high LiCl molality. The Pitzer–Simonson–Clegg (PSC) model was used to represent the experimental determined water activities of the titled system and the calculated values are discussed. Based on the calculated results, the turning point appears at about 17.0 mol kg −1 LiCl solution.
研究领域:
化学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Lijiang Guo,Haijun Han,Ouyang Dong,Yan Yao
Water activities of the high concentration solid solution-aqueous solution system (SS-AS) KCl–RbCl–H 2 O and its sub-binary systems at T = 298.15 K and T = 323.15 K have been elaborately measured by an isopiestic method. The solubility of this ternary system at T = (298.15, 308.15 and 323.15) K was also measured by a Flow-Cloud-Point method. A Pitzer model was used to estimate the reliability of the solubility reported in the literature, and to judge the type of solid phase, by correlating the measured water activity and the reported solubility values. The binary model parameters as a function of temperature between T = 298.15 K and T = 323.15 K were obtained by fitting the water activities in the binary systems. The predicted water activities at T = 298.15 K and T = 323.15 K with the obtained binary parameters only, are in good agreement with the experimental values, which indicate that the Pitzer model can reliably represent the properties of the ternary system, with binary parameters only within the temperature range from T = 298.15 K to T = 323.15 K. Under the different assumptions that the equilibrium solid phase involved the pure salts (KCl (s) and RbCl (s) ) for the ideal solid solution or regular solid solution (K, Rb)Cl (ss) , the solubility isotherms at T = (298.15, 308.15 and 323.15) K were calculated and compared to experimental results, respectively. It was found that only the calculated solubility isotherms for (K, Rb)Cl (ss) regular solid solution are consistent with the corresponding experimental values. The solid phase equilibrated with the aqueous solution in the KCl–RbCl–H 2 O ternary system should be a regular solid solution (K, Rb)Cl (ss) . This conclusion also can be verified from the Lippman log ∑ K − X s − X act and Φ ∑ m − X s − X aq equilibrium diagrams.
研究领域:
物理化学
·
热力学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 47
·37697-37702
·
IF 3.84
Liuyi Yin,Yufeng Hu,Xianming Zhang,Jianguang Qi,Weiting Ma
Batch reaction experiments were performed to investigate the salt effect on the yield of trioxane in the reaction solution. The salts considered include NaHSO4, Na2SO4, NaH2PO4, Na2HPO4, KCl, NaCl, LiCl, ZnCl2, MgCl2, and FeCl3. The effects of the anionic structure and the cation charge density on the yield of trioxane in the reaction solution were elucidated and the mechanisms that govern such effects were established. It is shown that the first four salts exerted a negative effect on the yield of trioxane in the reaction solution and such an effect increased progressively from left to right. This trend is due to the formation of NaHSO4, H3PO4, or (H3PO4 and NaH2PO4), which decreased the concentration of H+ in the solution. The latter six salts showed a positive effect on the yield of trioxane in the reaction solution. The salt effect paralleled the ability of the salt to decrease the water activity of the reaction solution and followed the order KCl < NaCl < LiCl < ZnCl2 < MgCl2 < FeCl3. Continuous production experiments were performed to investigate the salt effect on the concentration of trioxane in the distillate. The salts considered were KCl, NaCl, LiCl, ZnCl2, MgCl2, and FeCl3, and the salt effect increased progressively from left to right. Such an effect was shown to be determined by the ability of the salt to increase the yield of trioxane in the reaction solution and to increase the relative volatilities of trioxane and water and of trioxane and oligomers.
研究领域:
化学工程
·
工业化学
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2020
·
IF 7.182
Huijuan Wang,Heping Cui,Xuejiao Wang,Chao Lin,Shuqin Xia,Khizar Hayat,Shahzad Hussain,Muhammad Usman Tahir,Xiaoming Zhang
To obtain chitosan (CTS) with narrower molecular weight distribution, CTS with weight-average molecular weight ( M W ) of 197.30 kDa was first metal complexed and then degraded into five CTSs with M W of 107.90, 56.48, 10.40, 5.67 (CTS-4) and 3.66 kDa. Decrease of M W did not cause a significant change in chemical structure of the residue CTS, but the crystal structure was transformed significantly. The moisture retention increased firstly and then decreased as the M W of CTS decreased. CTS-4 was superior to CTSs with other M W and propylene glycol in terms of the moisture retention. The lower water activity and increase of net isosteric heat were observed in CTS-4, which was due to the migration of immobilized water to a bound-state caused by mounting newly formed chain-end hydrophilic groups per unit weight. CTS-4 could effectively improve moisture retention, showing a potential to substitute commonly used humectant such as propylene glycol.
研究领域:
材料科学
·
生物化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2018
·
IF 2.196
Lijiang Guo,Lanying Tu,Yaxiao Wang,Jianqiang Li
Water activities in the ternary system CsCl–MgCl2–H2O and its sub-binary systems at 323.15 K were elaborately measured by an isopiestic method. Moreover, the solubility of the CsCl–MgCl2–H2O system at 323.15 K was also measured by the flow-cloud-point method. A Pitzer model was used to predict the measured water activity and solubility data. The binary parameters for the CsCl–H2O system at 323.15 K were obtained by fitting the measured water activities for this binary system. The calculated water activity and solubility isotherms for the CsCl–MgCl2–H2O system at 323.15 K, with binary parameters only, deviated from the experimental values. This means that it is insufficient with binary parameters only to predict the water activity and calculate the solubility isotherms of the CsCl–MgCl2–H2O system at 323.15 K. The calculated solubility isotherms with both binary and mixing parameters, obtained by fitting the measured water activity, also deviated from experimental values. A new set of reasonable ternary parameters for the CsCl–MgCl2–H2O system was obtained by fitting the measured water activity and solubility data of this work. The calculated solubility isotherms with these parameters agreed with experimental results.
研究领域:
化学
·
物理化学
✓ 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 SOLUTION CHEMISTRY
·
2018
·Vol. 48
·期 3
·367-378
·
IF 1.401
Li Hongxia,Guo Lijiang,Li Jianqiang
The water activities of the MgCl 2 –RbCl–H 2 O ternary system and its sub-binary systems have been measured with the isopiestic method at 323.15 K. The measured water activities for the MgCl 2 –H 2 O and RbCl–H 2 O sub-binary systems agree well with the results reported in literature. The measured equal water activity lines of the MgCl 2 –RbCl–H 2 O ternary system are not straight lines, which means the mixing behavior of the solutions do not obey Zdanovskii’s rule. The solubility of the MgCl 2 –RbCl–H 2 O ternary system has been determined with the Flow-Cloud-Point method at 323.15 K, and the measured results are roughly consistent with values reported in the literature. The Pitzer model was selected to correlate the water activity and solubility data measured in this work. The predicted water activities and solubility isotherm for the MgCl 2 –RbCl–H 2 O ternary system at 323.15 K, with binary solution parameters only, both deviated from the experiment values. The ternary solution Pitzer model parameters were obtained by fitting the measured water activities in the ternary system. The water activities and solubility isotherms of the MgCl 2 –RbCl–H 2 O ternary system at 323.15 K were calculated including both binary and ternary solution parameters. The calculated water activities are consistent with the experimental values. The calculated solubility isotherms are roughly consistent with experiment values, except they deviate somewhat in the RbCl crystallization region.
研究领域:
化学
·
物理化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Kaiyu Zhao,Yafei Guo,Dan Li,Lingzong Meng,Tianlong Deng
Isopiestic molalities and water activities for the commercial absorption refrigerants LiBr and SrBr 2 at 288.15 K were accurately measured using an improved isopiestic method. And the solubilities for the absorption refrigeration systems were determined by the isothermal dissolution equilibrium method, meanwhile, the refractive indices and densities were measured. The Pitzer and HW model was used to correlate the measured water activities and solubilities, simulate the thermodynamic properties and predict the data in the phase equilibrium process for the absorption refrigeration systems, and the predicted data agreed well with the experimental solubilities. On the basis of the Pitzer ion-interaction parameters and solubility product constant ( K sp ) obtained in this work, the ion-interactions between alkali metal ions with Sr 2+ and phase equilibrium behaviors were illustrated on the molecular level, which could give an essential guide for the designing of absorption refrigeration system.
研究领域:
化学工程
·
制冷技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2021
·
IF 3.178
Tao Zhang,Lan Yang,Dan Li,Lingzong Meng,Yafei Guo,Tianlong Deng
The pH values, solubilities and water activities in the system LiB(OH) 4 –NaB(OH) 4 –H 2 O at 323.15 K were investigated. The mole fractions of boron species were calculated in the aqueous borate solutions, and the distribution and relevant mechanism were also discussed. The solubility diagrams in the ternary system were drawn at 323.15 K. The phase diagram consists of two single salt regions for LiB(OH) 4 and NaB(OH) 4 ·2H 2 O, one invariant point co-saturated with the above salts. On the basis of the Pitzer model, the Pitzer binary parameters and mixing parameters were fitted with the water activities, saturated vapour pressure and solubilities in the ternary system. The dissolution equilibrium constants ( K sp) of LiB(OH) 4 and NaB(OH) 4 ·2H 2 O were calculated using the experimental solubility data. The calculated solubilities with the parameters and K sp agree well with the experimental data.
研究领域:
物理化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2024
·
IF 2
Yi Hua,Jinqiu Ma,Shuaiqi Sun,Qingfen Meng,Dan Li,Yong Ma,Lingzong Meng,Guangli Zhou
The water activities and osmotic coefficients in the ternary system NaB(OH)4–Na2B4O5(OH)4–H2O at 323.15 K were investigated with the isopiestic method. The solubilities and physicochemical properties in the NaBO2–Na2B4O7–H2O system at 323.15 K were studied with the isothermal dissolution equilibrium method. The phase diagram in the system consists of two single salt regions for NaBO2·4H2O and Na2B4O7·10H2O, one invariant point saturated with the above salts, and two univariant solubility curves. On the basis of the Pitzer model, the Pitzer binary parameters of Na2B4O5(OH)4 and mixing parameters were fitted with the osmotic coefficients and solubilities. The dissolution equilibrium constant of Na2B4O7·10H2O was calculated with the experimental solubility data and parameters. The calculated solubilities and water activities with the parameters and dissolution equilibrium constants of NaBO2·4H2O and Na2B4O7·10H2O agree with the experimental data.
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）