The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficientsγ∞at infinite dilution of a...The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficientsγ∞at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation.In fact,the measurement ofγ∞by gas-liquid chromatography is a speedy and cost-saving method.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylben-zenes,styrene,in 1-allyl-3-methylimidazolium tetrafluorobo-rate([AMIM][BF4])and 1-butyl-3-methyl imidazolium hexafluorophosphate([BMIM][PF6]),1-isobutenyl-3-methylimidazolium tetrafluoroborate([MPMIM][BF4])and[MPMIM][BF4]-AgBF4 have been determined by gas-liquid chromatography using ionic liquids as stationary phase.The measurements were carried out at different temperatures from 298 to 318 K.The separating effects of these ionic liquids for alkanes/hexane,aliphatic hydrocarbons/benzene and hexene isomers have been discussed.The hydrophobic parameter,dipole element,frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method.The quantitative relations among the computed structure para-meters and activity coefficients at infinite dilution were also developed.The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.展开更多
Covalent organic frameworks(COFs)are crystalline materials composed of covalently bonded organic ligands with chemically permeable structures.Their crystallization is achieved by balancing thermal reversibility with t...Covalent organic frameworks(COFs)are crystalline materials composed of covalently bonded organic ligands with chemically permeable structures.Their crystallization is achieved by balancing thermal reversibility with the dynamic nature of the frameworks.Ionic covalent organic frameworks(ICOFs)are a subclass that incorporates ions in positive,negative,or zwitterionic forms into the frameworks.In particular,spiroborate-derived linkages enhance both the structural diversity and functionality of ICOFs.Unlike electroneutral COFs,ICOFs can be tailored by adjusting the types and arrangements of ions,influencing their formation mechanisms and physical properties.This study focuses on analyzing the graph-based structural characteristics of ICOFs with spiroborate linkages.We compute graph based entropy using hybrid topological descriptors that capture both local and global structural patterns.Furthermore,statistical regression models are developed to predict graph energies of larger-dimensional ICOF structures based on these descriptors.To ensure the robustness and accuracy of our results,we validated our findings using a pseudocode algorithm specifically designed for computing degree-based topological indices.This computational validation confirms the consistency of the derived descriptors and supports their applicability in quantitative structure-property relationship(QSPR)modeling.Overall,this approach provides valuable insights for future applications in material design and property prediction within the framework of ICOFs.展开更多
目的利用QSPR模型预测药物的经皮渗透性,并检验模型的准确性和适用性。方法以炔雌醇、α-细辛醚、非那甾胺和利培酮为模型药物,Potts-Guy,Cronin,Moss,Morrimoto,Kitagawa,Magnusson和Lien-Gao构建的七个数学等式为QSPR模型,用药物的理...目的利用QSPR模型预测药物的经皮渗透性,并检验模型的准确性和适用性。方法以炔雌醇、α-细辛醚、非那甾胺和利培酮为模型药物,Potts-Guy,Cronin,Moss,Morrimoto,Kitagawa,Magnusson和Lien-Gao构建的七个数学等式为QSPR模型,用药物的理化参数计算药物经皮渗透速率的预测值;同时采用离体人皮,在透皮扩散池中进行饱和药物溶液的体外经皮渗透实验。高效液相色谱法测定接受液中的药物浓度,计算药物的最大稳态经皮渗透速率。并将利用模型得到的理论预测值与实验所得的实际经皮渗透数值进行比较和分析,确定最适预测模型。结果采用7种预测模型所得到的理论预测值相对于实验值均在95%可信区间内,具有统计学意义。模型之间的准确度有很大差异,采用疏水性和相对分子质量为参数的模型拟合效果最好,根据均方根误差RMSE(Root Mean Square of Error),预测的准确性程度依次为Potts-Guy>Cronin>Kitagawa,Morimoto,Magnusson>Moss,Lien-Gao。结论QSPR模型能很好地预测药物的经皮渗透,Potts-Guy预测的准确性最佳。展开更多
QSPR models of PCDD/Fs were generated by means of kernel partial least squares. The molecular distance-edge vector method was used as descriptors to get model I for predicting PCDD/Fs retention behavior. The chlorinat...QSPR models of PCDD/Fs were generated by means of kernel partial least squares. The molecular distance-edge vector method was used as descriptors to get model I for predicting PCDD/Fs retention behavior. The chlorinated positions were also used and model II was obtained. In studied cases, the predictive ability of the KPLS model is comparable or superior to those of PLS and ANN. The results indicate that KPLS can be used as an alternative powerful modeling tool for QSPR studies.展开更多
基金supported by the Science Foundation of China Petroleum&Chemical Corporation(Grant No.X504031).
文摘The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficientsγ∞at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation.In fact,the measurement ofγ∞by gas-liquid chromatography is a speedy and cost-saving method.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylben-zenes,styrene,in 1-allyl-3-methylimidazolium tetrafluorobo-rate([AMIM][BF4])and 1-butyl-3-methyl imidazolium hexafluorophosphate([BMIM][PF6]),1-isobutenyl-3-methylimidazolium tetrafluoroborate([MPMIM][BF4])and[MPMIM][BF4]-AgBF4 have been determined by gas-liquid chromatography using ionic liquids as stationary phase.The measurements were carried out at different temperatures from 298 to 318 K.The separating effects of these ionic liquids for alkanes/hexane,aliphatic hydrocarbons/benzene and hexene isomers have been discussed.The hydrophobic parameter,dipole element,frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method.The quantitative relations among the computed structure para-meters and activity coefficients at infinite dilution were also developed.The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.
文摘Covalent organic frameworks(COFs)are crystalline materials composed of covalently bonded organic ligands with chemically permeable structures.Their crystallization is achieved by balancing thermal reversibility with the dynamic nature of the frameworks.Ionic covalent organic frameworks(ICOFs)are a subclass that incorporates ions in positive,negative,or zwitterionic forms into the frameworks.In particular,spiroborate-derived linkages enhance both the structural diversity and functionality of ICOFs.Unlike electroneutral COFs,ICOFs can be tailored by adjusting the types and arrangements of ions,influencing their formation mechanisms and physical properties.This study focuses on analyzing the graph-based structural characteristics of ICOFs with spiroborate linkages.We compute graph based entropy using hybrid topological descriptors that capture both local and global structural patterns.Furthermore,statistical regression models are developed to predict graph energies of larger-dimensional ICOF structures based on these descriptors.To ensure the robustness and accuracy of our results,we validated our findings using a pseudocode algorithm specifically designed for computing degree-based topological indices.This computational validation confirms the consistency of the derived descriptors and supports their applicability in quantitative structure-property relationship(QSPR)modeling.Overall,this approach provides valuable insights for future applications in material design and property prediction within the framework of ICOFs.
文摘目的利用QSPR模型预测药物的经皮渗透性,并检验模型的准确性和适用性。方法以炔雌醇、α-细辛醚、非那甾胺和利培酮为模型药物,Potts-Guy,Cronin,Moss,Morrimoto,Kitagawa,Magnusson和Lien-Gao构建的七个数学等式为QSPR模型,用药物的理化参数计算药物经皮渗透速率的预测值;同时采用离体人皮,在透皮扩散池中进行饱和药物溶液的体外经皮渗透实验。高效液相色谱法测定接受液中的药物浓度,计算药物的最大稳态经皮渗透速率。并将利用模型得到的理论预测值与实验所得的实际经皮渗透数值进行比较和分析,确定最适预测模型。结果采用7种预测模型所得到的理论预测值相对于实验值均在95%可信区间内,具有统计学意义。模型之间的准确度有很大差异,采用疏水性和相对分子质量为参数的模型拟合效果最好,根据均方根误差RMSE(Root Mean Square of Error),预测的准确性程度依次为Potts-Guy>Cronin>Kitagawa,Morimoto,Magnusson>Moss,Lien-Gao。结论QSPR模型能很好地预测药物的经皮渗透,Potts-Guy预测的准确性最佳。
基金the National Natural Science Foundation of China(No.20275026).
文摘QSPR models of PCDD/Fs were generated by means of kernel partial least squares. The molecular distance-edge vector method was used as descriptors to get model I for predicting PCDD/Fs retention behavior. The chlorinated positions were also used and model II was obtained. In studied cases, the predictive ability of the KPLS model is comparable or superior to those of PLS and ANN. The results indicate that KPLS can be used as an alternative powerful modeling tool for QSPR studies.
