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Hu Y.,Nanjing University of Technology | Yang Y.,Nanjing University of Technology | Cao Y.,Jiangsu Province Hospital | Li Y.,Taiyuan Qiaoyou Chemical Industrial Co. | And 2 more authors.
Fluid Phase Equilibria | Year: 2015

In this work, the solid-liquid equilibrium (SLE) of 2,5-thiophenedicarboxylic acid in (acetic acid. +. ethanol) binary solvent mixtures was explored at temperatures ranging from 283.15. K to 328.15. K under atmosphere pressure. For the temperature range investigated, the equilibrium solubility varies with the composition of the solvent and temperature. The equilibrium solubility data were then modelled using modified Apelblat equation, a variant of the combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) model and Jouyban-Acree model. Computational results showed that the modified Apelblat equation and CNIBS/R-K model have the low MD (mean deviation). In addition, the thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were calculated by the van't Hoff analysis. © 2015 Elsevier B.V.


Wang K.,Nanjing University of Technology | Hu Y.,Nanjing University of Technology | Yang W.,Nanjing University of Technology | Guo S.,Nanjing University of Technology | Shi Y.,Taiyuan Qiaoyou Chemical Industrial Co.
Journal of Chemical Thermodynamics | Year: 2012

The solubility of 2,3,4,5-tetrabromothiophene were measured in methanol, ethanol, propan-1-ol, butan-1-ol, toluene, ethyl formate, ethyl acetate, trichloromethane and oxolane within the temperature range between 278.05 K and 325.15 K under atmospheric pressure by gravimetric method. The solubility of 2,3,4,5-tetrabromothiophene in those selected solvents increased with increasing temperature. The solubility data were correlated with the van't Hoff equation, the modified Apelblat equation and the 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 ethyl acetate had the potential as a better solvent in the re-crystallization process of 2,3,4,5-tetrabromothiophene. © 2012 Elsevier Ltd. All rights reserved.


Wang K.,Nanjing University of Technology | Zhang T.,Nanjing University of Technology | Hu Y.,Nanjing University of Technology | Yang W.,Nanjing University of Technology | Shi Y.,Taiyuan Qiaoyou Chemical Industrial Co.
Electrochimica Acta | Year: 2014

A novel heterocycle-based monomer (BEDOT-V-NEtCz) is designed and synthesized using 3,4-ethylenedioxythiophene (EDOT) as the end units and 3,6-linked N-ethyl-carbazole (NEtCz) as the inner unit spaced by vinylene (V). The monomer BEDOT-V-NEtCz can be electrochemically oxidized at a very low onset potential of 0.41 V vs SCE. The resulting electroactive polymer (PBEDOT-V-NEtCz) is electrochemically synthesized by cyclic voltammetry (CV) method and its electrochromic properties are reported. Characterizations of PBEDOT-V-NEtCz film are performed by CV, scanning electron microscopy (SEM) and differential scanning calorimeter (DSC). Spectroelectrochemical analysis reveals that PBEDOT-V-NEtCz film shows multicolored electrochromism: brick-red in the reduced state, sky-blue in the oxidized state and three intermediate colors (brown at 0.2 V, olive green at 0.4 V and blue-green at 0.6 V vs SCE). The color changes are accompanied by good optical contrasts of 50% at 759 nm and 27% at 470 nm, respectively. Kinetic studies reveal that the switching time of PBEDOT-V-NEtCz film are 1.2s (759 nm) and 1.9s (470 nm) for the bleaching process and 1.4s (759 nm) and 1.8s (470 nm) for the coloration process (95% of the full ΔT%), respectively. The resultant polymer could be useful as the active layers in electrochromic devices. © 2014 Elsevier Ltd.


Zhang Q.,Nanjing University of Technology | Hu Y.,Nanjing University of Technology | Shi Y.,Taiyuan Qiaoyou Chemical Industrial Co. | Yang Y.,Nanjing University of Technology | And 3 more authors.
Journal of Chemical and Engineering Data | Year: 2014

Data on corresponding solid-liquid equilibrium of dibenzothiophene (DBT) in different solvents are essential for a preliminary study of industrial applications. In this study, the solubility behavior of DBT in different solvents, such as methanol, ethanol, isopropyl alcohol, butan-1-ol, formic acid, and acetonitrile at temperatures ranging from (278.15 to 328.15) K was investigated. An analytical stirred-flask method was employed to measure the dissolubility of DBT. For the temperature range investigated, the solubility of dibenzothiophene in the solvents increased with increasing temperature. The thermodynamic models, such as the Van 't Hoff model, the modified Apelblat model and the Buchowski-Ksiazaczak λh model were investigated to describe the experimental data. It was found that the modified Apelblat model was the most suitable for predicting the solubility behavior of DBT with a temperature increment. The calculated thermodynamic parameters indicated that in each studied solvent the dissolution process of DBT is endothermic. © 2014 American Chemical Society.


Yang W.,Nanjing University of Technology | Chen Z.,Nanjing University of Technology | Jiang X.,Nanjing University of Technology | Hu Y.,Nanjing University of Technology | And 3 more authors.
Journal of Molecular Liquids | Year: 2013

Abstract The solubility of succinic anhydride in acetone, acetonitrile, 2-propanol, ethyl acetate, acetonitrile + ethyl acetate, acetone + ethyl acetate was determined with temperature range from 278.15 to 333.15 K under atmospheric pressure using the analytical stirred-flask method. The solubility of succinic anhydride in these solvents increased with increasing temperature. The experimental data were well correlated with the modified Apelblat equation and the Buchwski-Ksiazaczak λh equation. © 2012 Elsevier B.V.


Wang K.,Nanjing University of Technology | Hu Y.,Nanjing University of Technology | Yang W.,Nanjing University of Technology | Shi Y.,Taiyuan Qiaoyou Chemical Industrial Co. | Li Y.,Taiyuan Qiaoyou Chemical Industrial Co.
Thermochimica Acta | Year: 2012

Solubility data were measured for succinimide in pure ethyl acetate, acetonitrile, ethanol, acetone, tetrahydrofuran, methanol, isopropanol, n-butanol and binary methanol + ethyl acetate solvent mixtures at the temperature range between 278.2 K and 325.1 K under atmospheric pressure by gravimetric method. The solubilities of succinimide in those selected solvents increased with increasing temperature. The solubility data were correlated with the modified Apelblat equation and λh equation to obtain the model parameters. The experimental results could be useful for optimizing the process of purification of succinimide in industry. Methanol could be the excellent solvent in the crystallization of succinimide. © 2012 Elsevier B.V.


Zhang Q.,Nanjing University of Technology | Yang Y.,Nanjing University of Technology | Cao C.,Nanjing University of Technology | Cheng L.,Nanjing University of Technology | And 3 more authors.
Journal of Chemical Thermodynamics | Year: 2015

In this paper, we focused on solubility and solution thermodynamics of dibenzothiophene. By the gravimetric method, the solubility of dibenzothiophene was measured in (methanol + acetonitrile) binary solvent mixtures at temperatures from (278.15 to 333.15) K under atmosphere pressure. The solubility data were fitted using a modified Apelblat equation, a variant of the combined nearly ideal binary solvent/Redich-Kister (CNIBS/R-K) model and Jouyban-Acree model. Computational results showed that the modified Apelblat equation was superior to the other two equations. In addition, the thermodynamic properties of the solution process, including the Gibbs free energy, enthalpy, and entropy, were calculated by the van't Hoff analysis. The experimental results showed that methanol could be used as effective anti-solvents in the crystallization process. © 2014 Elsevier Ltd. All rights reserved.


Zhi W.,Nanjing University of Technology | Hu Y.,Nanjing University of Technology | Liang M.,Nanjing University of Technology | Liu Y.,Nanjing University of Technology | And 3 more authors.
Fluid Phase Equilibria | Year: 2014

In this paper, the solid-liquid equilibrium of 2,5-thiophenedicarboxylic acid in methanol, ethanol, i-propanol, n-butanol, acetic acid, n-hexane, acetonitrile and acetone was explored from 278.15. K to 333.15. K under atmosphere pressure. Modified Apelblat equation and λh equation were adopted to describe and predict the change tendency of solubility. Besides, the thermodynamic properties of the dissolution process, including enthalpy, entropy and Gibbs energy, were calculated by means of van't Hoff analysis and Gibbs equation. Based on the analysis above, ethanol is considered to be the best solvent in crystallization process of 2,5-thiophenedicarboxylic acid. © 2014 Elsevier B.V.


Liu X.,Nanjing University of Technology | Hu Y.,Nanjing University of Technology | Liang M.,Nanjing University of Technology | Li Y.,Taiyuan Qiaoyou Chemical Industrial Co. | And 2 more authors.
Fluid Phase Equilibria | Year: 2014

Data on corresponding solid-liquid equilibrium of maleic anhydride in different organic solvents are essential for industrial design and further theoretical studies. In this study, the solubilities of maleic anhydride were measured in DMF, methanol, acetic acid, acetonitrile, acetone, ethyl acetate, 2-propanol and n-butyl alcohol with the temperature range of 278.15-323.15. K by the analytical stirred-flask method under atmospheric pressure. The experiment results indicated that the solubility of maleic anhydride was highest in DMF and followed by methanol, acetic acid, acetonitrile, acetone, ethyl acetate, 2-propanol and n-butyl alcohol. For the temperature range investigated, the solubilities of maleic anhydride in the organic solvents increased with increasing temperature. Results of these measurements were well-correlated with the modified Apelblat equation, the Buchowski-Ksiazaczak λh equation and the van't Hoff equation. The calculated solubilities showed good agreement with the experimental data. The modified Apelblat equation was found to regress the solubility data is higher accuracy than the Buchowski-Ksiazaczak λh equation. The experimental data and model parameters would be useful for optimizing the process of purification of maleic anhydride in industry. © 2014.


Wu K.,Nanjing University of Technology | Hu Y.,Nanjing University of Technology | Yang W.,Nanjing University of Technology | Zhang T.,Nanjing University of Technology | And 3 more authors.
Fluid Phase Equilibria | Year: 2014

The solubility of N-Ethylcarbazole in methanol, ethanol, n-propanol, isopropanol, 1-butanol, 1-pentanol and petroleum ether was measured over the temperature range of 279.15-319.15. K at around 4. K intervals under atmospheric pressure. Experimental result showed that the solubility of N-Ethylcarbazole in seven solvents increased with the increasing temperature and they were in good agreement with the calculated solubility of the modified Apelblat equation and the λh equation. The thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were calculated by the van't Hoff analysis. The values of both the standard molar enthalpy change and standard molar Gibbs energy change of solution were positive, which indicated that the process was endothermic. © 2014 Elsevier B.V.

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