目的:采用真实溶剂似导体屏蔽模型(conductor-like screening model for real solvents,COSMO)预测制何首乌中大黄素在不同溶剂中的提取情况,筛选最佳提取溶剂并对提取机理进行解释。方法:利用COSMO模型预测了1,3-丙二醇-乳酸(1∶3)制...目的:采用真实溶剂似导体屏蔽模型(conductor-like screening model for real solvents,COSMO)预测制何首乌中大黄素在不同溶剂中的提取情况,筛选最佳提取溶剂并对提取机理进行解释。方法:利用COSMO模型预测了1,3-丙二醇-乳酸(1∶3)制备的天然低共熔溶剂(natural deep eutectic solvents,NADESs)与传统低共熔溶剂(traditional deep eutectic solvents,DESs)对制何首乌中大黄素的提取情况,并通过试验验证该模型预测结果的准确性,进一步解释提取机理。结果:经COSMO模型预测,大黄素与1,3-丙二醇-乳酸(1∶3)组成的NADES间的相互作用能为-762.8972 kJ/mol,显著高于大黄素与甲醇和水间的相互作用能。相互作用能越大,提取效率越高。最终预测大黄素提取效率由高到低依次为1,3-丙二醇-乳酸(1∶3)、甲醇、水。经试验进一步验证,NADES对大黄素的提取率为1.1266 mg/g,提取效率是水的16.07倍,甲醇的1.19倍,整体趋势与COSMO模型预测结果一致。结论:COSMO模型不仅可以准确预测大黄素在不同溶剂中的溶解规律,还可以从微观角度解释提取机理,可为各类天然产物高效提取溶剂的选择提供一定借鉴。展开更多
The adjustable parameters in the popular conductor-like screening model for real solvents(COSMO-RS)within the Amsterdam density functional(ADF)framework have been re-optimized to fit for the systems containing ionic l...The adjustable parameters in the popular conductor-like screening model for real solvents(COSMO-RS)within the Amsterdam density functional(ADF)framework have been re-optimized to fit for the systems containing ionic liquids(ILs).To get the optimal values of misfit energy constant a^0,hydrogen bond coefficient c_(hb)and effective contact surface area of a segment a_(eff),2283 activity coefficient data points at infinite dilution and 1433 CO_2 solubility data points exhaustively collected from references were used as training set.The average relative deviations(ARDs)of activity coefficients at infinite dilution and CO_2 solubility between experimental data and predicted values are 32.22%and17.61%,respectively,both of which are significantly lower than the original COSMO-RS versions.Predictions for other activity coefficients of solutes in ILs,solubility data of CO_2 in pure ILs and the binary mixtures of ILs at either high or low temperatures,and vapor–liquid equilibrium(VLE)for binary systems involving ILs have also been performed to demonstrate the validity of the parameterization of COSMO-RS model for ILs.The results showed that the predicted results by COSMO-RS model with the new optimized parameters are in much better agreement with experimental data than those by the original versions over a wide temperature and pressure range.The COSMO-RS model for ILs presented in this work improves the prediction accuracy of thermodynamic properties for the systems containing ILs,which is always highly desirable for general chemical engineers.展开更多
本文基于量子化学理论,采用真实溶剂似导体屏蔽模型(Conductor like Screening Model for Realistic Solvents,COSMO-RS)模拟了单一制冷工质的饱和蒸汽压和混合制冷工质的气液相平衡性质。将模拟结果与实验数据进行比较,最大误差不超过5...本文基于量子化学理论,采用真实溶剂似导体屏蔽模型(Conductor like Screening Model for Realistic Solvents,COSMO-RS)模拟了单一制冷工质的饱和蒸汽压和混合制冷工质的气液相平衡性质。将模拟结果与实验数据进行比较,最大误差不超过5%。模拟结果与实验数据有很好的一致性,表明:运用该方法预测制冷剂的热力学性质是可行的。展开更多
In this work,the solubility data and liquid-phase mass transfer coefficients of hydrogen(H2),methane(CH4)and their mixtures in vacuum gas oil(VGO)at temperatures(353.15-453.15 K)and pressures(1-7 MPa)were measured,whi...In this work,the solubility data and liquid-phase mass transfer coefficients of hydrogen(H2),methane(CH4)and their mixtures in vacuum gas oil(VGO)at temperatures(353.15-453.15 K)and pressures(1-7 MPa)were measured,which are necessary for catalytic cracking process simulation and design.The solubility of H2 and CH4 in VGO increases with the increase of pressure,but decreases with the increase of temperature.Henry’s constants of H2 and CH4 follow the relation of In H=-413.05/T+5.27 and In H=-990.67/T+5.87,respectively.The molar fractions of H2 and system pressures at different equilibrium time were measured to estimate the liquid-phase mass transfer coefficients.The results showed that with the increase of pressure,the liquid-phase mass transfer coefficients increase.Furthermore,the solubility of H2 and CH4 in VGO was predicted by the predictive COSMO-RS model,and the predicted values agree well with experimental data.In addition,the gas-liquid equilibrium(GLE)for H2+CH4+VGO system at different feeding gas ratios in volume fraction(i.e.,H285%+CH415%and H290%+CH410%)was measured.The selectivity of H2 to CH4 predicted by the COSMO-RS model agrees well with experimental data.This work provides the basic thermodynamic and dynamic data for fuel oil catalytic cracking processes.展开更多
水飞蓟素是水飞蓟种子提取出的黄酮类生物活性成分,具有保肝利胆等多种药理功能,其中水飞蓟宾活性及含量最高,本研究利用天然低共熔溶剂(Natural Deep Eutectic Solvent,NADES),对水飞蓟宾的高效提取工艺与机理进行研究。以粉碎脱脂后...水飞蓟素是水飞蓟种子提取出的黄酮类生物活性成分,具有保肝利胆等多种药理功能,其中水飞蓟宾活性及含量最高,本研究利用天然低共熔溶剂(Natural Deep Eutectic Solvent,NADES),对水飞蓟宾的高效提取工艺与机理进行研究。以粉碎脱脂后的水飞蓟种壳粉为原料,用初步筛选所得较优NADES,即:氯化胆碱+1,4-丁二醇进行提取,HPLC法测定水飞蓟宾含量,在单因素实验基础上,采用响应面法对该NADES提取水飞蓟宾工艺进行优化。结果表明:料液比1:20 g/mL,提取温度77.0℃、时间5.6 h,模型预测水飞蓟宾得率可达4.29%,与实验值4.30%基本一致。基于片段活度系数类导体屏蔽模型(Conductor-like Screening Model for Segment Activity Coefficient,COSMO-SAC),分别对水飞蓟宾和溶剂分子(NADES与传统溶剂乙醇)进行结构与能量优化,通过量子化学计算,得到水飞蓟宾在两种溶剂中的无限稀释活度系数的对数分别为-6.922和-6.043,分子间相互作用能分别为-51.62和-25.47 kJ/mol,以探讨不同溶剂提取水飞蓟宾效果差异机理。展开更多
文摘目的:采用真实溶剂似导体屏蔽模型(conductor-like screening model for real solvents,COSMO)预测制何首乌中大黄素在不同溶剂中的提取情况,筛选最佳提取溶剂并对提取机理进行解释。方法:利用COSMO模型预测了1,3-丙二醇-乳酸(1∶3)制备的天然低共熔溶剂(natural deep eutectic solvents,NADESs)与传统低共熔溶剂(traditional deep eutectic solvents,DESs)对制何首乌中大黄素的提取情况,并通过试验验证该模型预测结果的准确性,进一步解释提取机理。结果:经COSMO模型预测,大黄素与1,3-丙二醇-乳酸(1∶3)组成的NADES间的相互作用能为-762.8972 kJ/mol,显著高于大黄素与甲醇和水间的相互作用能。相互作用能越大,提取效率越高。最终预测大黄素提取效率由高到低依次为1,3-丙二醇-乳酸(1∶3)、甲醇、水。经试验进一步验证,NADES对大黄素的提取率为1.1266 mg/g,提取效率是水的16.07倍,甲醇的1.19倍,整体趋势与COSMO模型预测结果一致。结论:COSMO模型不仅可以准确预测大黄素在不同溶剂中的溶解规律,还可以从微观角度解释提取机理,可为各类天然产物高效提取溶剂的选择提供一定借鉴。
基金financially supported by the National Natural Science Foundation of China under Grants (Nos. 21476009, 21406007 and U1462104)
文摘The adjustable parameters in the popular conductor-like screening model for real solvents(COSMO-RS)within the Amsterdam density functional(ADF)framework have been re-optimized to fit for the systems containing ionic liquids(ILs).To get the optimal values of misfit energy constant a^0,hydrogen bond coefficient c_(hb)and effective contact surface area of a segment a_(eff),2283 activity coefficient data points at infinite dilution and 1433 CO_2 solubility data points exhaustively collected from references were used as training set.The average relative deviations(ARDs)of activity coefficients at infinite dilution and CO_2 solubility between experimental data and predicted values are 32.22%and17.61%,respectively,both of which are significantly lower than the original COSMO-RS versions.Predictions for other activity coefficients of solutes in ILs,solubility data of CO_2 in pure ILs and the binary mixtures of ILs at either high or low temperatures,and vapor–liquid equilibrium(VLE)for binary systems involving ILs have also been performed to demonstrate the validity of the parameterization of COSMO-RS model for ILs.The results showed that the predicted results by COSMO-RS model with the new optimized parameters are in much better agreement with experimental data than those by the original versions over a wide temperature and pressure range.The COSMO-RS model for ILs presented in this work improves the prediction accuracy of thermodynamic properties for the systems containing ILs,which is always highly desirable for general chemical engineers.
文摘本文基于量子化学理论,采用真实溶剂似导体屏蔽模型(Conductor like Screening Model for Realistic Solvents,COSMO-RS)模拟了单一制冷工质的饱和蒸汽压和混合制冷工质的气液相平衡性质。将模拟结果与实验数据进行比较,最大误差不超过5%。模拟结果与实验数据有很好的一致性,表明:运用该方法预测制冷剂的热力学性质是可行的。
基金Supported by the National Natural Science Foundation of China(U1862103).
文摘In this work,the solubility data and liquid-phase mass transfer coefficients of hydrogen(H2),methane(CH4)and their mixtures in vacuum gas oil(VGO)at temperatures(353.15-453.15 K)and pressures(1-7 MPa)were measured,which are necessary for catalytic cracking process simulation and design.The solubility of H2 and CH4 in VGO increases with the increase of pressure,but decreases with the increase of temperature.Henry’s constants of H2 and CH4 follow the relation of In H=-413.05/T+5.27 and In H=-990.67/T+5.87,respectively.The molar fractions of H2 and system pressures at different equilibrium time were measured to estimate the liquid-phase mass transfer coefficients.The results showed that with the increase of pressure,the liquid-phase mass transfer coefficients increase.Furthermore,the solubility of H2 and CH4 in VGO was predicted by the predictive COSMO-RS model,and the predicted values agree well with experimental data.In addition,the gas-liquid equilibrium(GLE)for H2+CH4+VGO system at different feeding gas ratios in volume fraction(i.e.,H285%+CH415%and H290%+CH410%)was measured.The selectivity of H2 to CH4 predicted by the COSMO-RS model agrees well with experimental data.This work provides the basic thermodynamic and dynamic data for fuel oil catalytic cracking processes.
文摘水飞蓟素是水飞蓟种子提取出的黄酮类生物活性成分,具有保肝利胆等多种药理功能,其中水飞蓟宾活性及含量最高,本研究利用天然低共熔溶剂(Natural Deep Eutectic Solvent,NADES),对水飞蓟宾的高效提取工艺与机理进行研究。以粉碎脱脂后的水飞蓟种壳粉为原料,用初步筛选所得较优NADES,即:氯化胆碱+1,4-丁二醇进行提取,HPLC法测定水飞蓟宾含量,在单因素实验基础上,采用响应面法对该NADES提取水飞蓟宾工艺进行优化。结果表明:料液比1:20 g/mL,提取温度77.0℃、时间5.6 h,模型预测水飞蓟宾得率可达4.29%,与实验值4.30%基本一致。基于片段活度系数类导体屏蔽模型(Conductor-like Screening Model for Segment Activity Coefficient,COSMO-SAC),分别对水飞蓟宾和溶剂分子(NADES与传统溶剂乙醇)进行结构与能量优化,通过量子化学计算,得到水飞蓟宾在两种溶剂中的无限稀释活度系数的对数分别为-6.922和-6.043,分子间相互作用能分别为-51.62和-25.47 kJ/mol,以探讨不同溶剂提取水飞蓟宾效果差异机理。
