The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Runcang Sun - One of the best experts on this subject based on the ideXlab platform.
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sequential solvent fractionation of heterogeneous bamboo organosolv lignin for value added application
Separation and Purification Technology, 2012Co-Authors: Shaoni Sun, Runcang SunAbstract:Abstract Value-added utilization of lignin is affected by its heterogeneous nature. In this case, bamboo organosolv lignin was successively fractionated with organic solvents of increasing Dissolving Capacity (i.e., ether, ethyl acetate, methanol, acetone, and dioxane/water) to obtain homogeneous preparations. The starting lignin and the fractions obtained were compared in terms of molecular weight distribution and functional groups by a set of chemistry and spectroscopy technologies. It was found that the yield of the five fractions obtained was 2.80%, 39.85%, 18.64%, 23.38%, and 13.30%, respectively. The lignin fraction extracted with ethyl acetate contained homogeneous materials of low molecular weight whereas the lignin fraction extracted with acetone was composed of a mixture of medium and high molecular weight materials. As evidenced by sugar analysis, there was strong association between hemicelluloses and lignin in the preparations with different molecular weights. Spectroscopy analysis indicates that with increasing the Dissolving Capacity of solvent, the contents of methoxyl, phenolic, and aliphatic hydroxyl groups in the extracted lignin fractions were decreased. The lignin fraction extracted with ethyl acetate, having a high radical scavenging index (RSI), will be a good feedstock as stabilizer. The results above suggest that the sequential solvent fractionation provides a promising way to prepare lignin with homogeneous structure and good functional properties for potential application.
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Homogeneous synthesis of hemicellulosic succinates with high degree of substitution in ionic liquid
Carbohydrate Polymers, 2011Co-Authors: Xinwen Peng, Junli Ren, Linxin Zhong, Runcang SunAbstract:Abstract Chemical modification is the most important means to obtain novel biopolymers and biomaterials from the abundant biomacromolecules. In this paper, hemicellulosic succinate, which is very important biomacromolecule for the preparation of functional materials, was homogeneously prepared in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid. The influence of reaction conditions used in this work on the degree of substitution (DS) was investigated, and the chemical structure and the thermal stability of hemicellulosic succinate were characterized by FT-IR and 13 C NMR spectroscopies as well as thermogravimetry. A high DS of up to 1.80 could be achieved at short time scale in [BMIM]Cl ionic liquid without any catalysts, which is probably due to the excellent Dissolving Capacity and catalytic effect of ionic liquid. These results indicate that ionic liquids open up totally new opportunities for chemically functionalization of hemicelluloses.
Jian Chen - One of the best experts on this subject based on the ideXlab platform.
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Structure-Solubility Correlation Model for Carbon Dioxide in Ionic Liquids
Industrial & Engineering Chemistry Research, 2012Co-Authors: Xin Wang, Jian ChenAbstract:In this work, the density distributions of carbon dioxide around different ionic liquids are calculated using the three-dimensional reference interaction site model integral equation. According to the density distributions, the corresponding excess adsorptions are calculated to estimate the solubilities of carbon dioxide in these ionic liquids. Some predicted results are in good agreement with available experimental data, showing that the structure descriptions are accurate and the direct correlation of solubility with structure is reasonable at low temperature and pressure. As a result, the present theoretical model provides a simple and efficient tool to evaluate Dissolving Capacity of ionic liquids and their mixtures.
G. Steen - One of the best experts on this subject based on the ideXlab platform.
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In vitro comparison of different gall stone dissolution solvents.
Gut, 1991Co-Authors: H. Vergunst, Onno T. Terpstra, H. G. T. Nijs, G. SteenAbstract:Extracorporeal shockwave lithotripsy (ESWL) of gall bladder stones leaves residual fragments that need to be dissolved by chemical solvents. In this study we compared the in vitro Dissolving Capacity of methyl tert-butyl ether (MTBE), mono-octanoin, limonene, and limonene/mono-octanoin (70%/30%). From nine sets of five human gall stones obtained at cholecystectomy, four stones were used for dissolution and the fifth was used for chemical analysis of cholesterol, calcium, and bilirubin contents. Eight sets were cholesterol stones with a mean (SD) cholesterol content of 89.9 (5.6)%. These stones dissolved completely in either solvent, often leaving sand-like debris, with the exception of one stone. MTBE dissolved cholesterol gall stones 100 times faster than mono-octanoin and 10 times faster than limonene or the limonene/mono-octanoin mixture (p less than 0.001). The combination of limonene and mono-octanoin was as effective as limonene alone. Of the four solvents, MTBE is the best one to evaluate for dissolution of residual fragments after ESWL treatment of gall bladder stones.
Cuicui Ling - One of the best experts on this subject based on the ideXlab platform.
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Extraction of Kerogen from Oil Shale with Supercritical Carbon Dioxide: Molecular Dynamics Simulations
The Journal of Supercritical Fluids, 2016Co-Authors: Qingzhong Xue, Yehan Tao, Yakang Jin, Cuicui LingAbstract:Abstract The extraction process and mechanism of kerogen moieties with supercritical CO 2 are elucidated using molecular dynamics simulations. It is demonstrated that supercritical CO 2 can effectively dissolve the kerogen moieties adsorbed onto the shale surface, and the kerogen moieties dissolved in supercritical CO 2 can be easily extracted from oil shale, because the interaction between the kerogen moieties dissolved in supercritical CO 2 and the shale surface is greatly reduced. The Dissolving Capacity of supercritical CO 2 is found to effectively increase with increasing pressure before the pressure reaches a critical value (approximately 50 MPa) and then increases slowly. Moreover, the Dissolving Capacity of supercritical CO 2 increases with increasing temperature at high pressure, which is consistent with experimental results. In addition, the hydroxyl functional groups modified on the shale surface promote the extraction of kerogen moieties with supercritical CO 2, and the polar kerogen moieties were more easily dissolved in supercritical CO 2 .
Jian-zhong Yin - One of the best experts on this subject based on the ideXlab platform.
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Study on the Phase Behavior and Molecular Dynamics Simulation of a Supercritical Carbon Dioxide Microemulsion Containing Ionic Liquid
Industrial & Engineering Chemistry Research, 2017Co-Authors: Hong-rui Ren, Xiang-dong Liang, Dan Zhou, Jian-zhong YinAbstract:We investigated the solubilization effect of a supercritical carbon dioxide microemulsion based on LS-mn (LS-36, LS-45, and LS-54) surfactants for 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) as well as the influencing factors by analyzing the cloud point pressure (CPP) curves, which served as a function of dissolved IL concentration. Results show that increased water content (W0) could enhance [Bmim][BF4] dissolution. Under the same conditions, microemulsion systems consisting of LS-54, LS-45, and LS-36 have the gradually decreased the Dissolving Capacity for [Bmim][BF4]. However, variation of the surfactant concentration has little influence on Dissolving [Bmim][BF4]. In addition, introducing appropriate amounts of ethanol could decrease the CPP of the system, which did not bring significant enhancement on [Bmim][BF4] dissolution. Molecular dynamics (MD) simulation was implemented to give an insight about the microstructure and prove the formation of the microemulsion.