Prediction of vapor–liquid equilibria of alcohol+hydrocarbon systems by 1H NMR spectroscopy

Reply to the comments on “Assessing the use of NMR chemical shifts for prediction of VLE in non-ideal binary liquid mixtures” by C. D׳Agostino

“…The VLE prediction results of alcohol-hydrocarbon systems by 1 H NMR chemical shift obtained from Dr. C. D'Agostino were consistent with the prediction results presented in our article (Xu et al, 2012). The prediction results of 1-propanolþwater, 2-propanol þ-water, acetone þwater, and acetoneþchloroform mixtures by 1 H NMR chemical shift were less accurate, indicating that our method in its present state was not suitable for the above cross-associated mixtures and should be improved.…”

“…Our article (Xu et al, 2012) also expressed whether the VLE prediction method could be used for other non-ideal systems which would be explored by us in the near future, but we believed that there must be some relationship between the spectroscopic and thermodynamic properties, which might be more interesting and important from a scientific point of view.…”

“…The aim of our article (Xu et al, 2012) was not only to predict VLE data for alcohol-hydrocarbon systems, but also to establish the relationship between 1 H NMR chemical shift and VLE data for some alcohol-hydrocarbon systems. Our article (Xu et al, 2012) also expressed whether the VLE prediction method could be used for other non-ideal systems which would be explored by us in the near future, but we believed that there must be some relationship between the spectroscopic and thermodynamic properties, which might be more interesting and important from a scientific point of view.…”

The Effect of C4H and C5H on the Microstructure of Aqueous Solutions of 1‐Alkyl‐3‐methylimidazolium Tetrafluoroborate Ionic Liquids

“…[29] According to Wilson'sl ocal compositionc oncept, [30] the local area composition of molecule i of ab inarym ixture is related to the mole fraction x i ,a veragea rea fraction q i ,a nd the interaction-energy parameter between j-i and i-i pairs of molecules (g ji -g ii ). Therefore, the local area composition of am olecule for ab inary system can be defined by Equations (2)- (4):…”

“…One can see from Ta ble 1a nd Figure 1t hat the concentration-dependent 1 HNMR chemical shifts of the studied systems correlatew ell with the LC model.I no ur previousw ork, the interaction-energy parameters of alcohol-hydrocarbons ystems obtainedf rom 1 HNMR chemical shifts have been used to predict vapor-liquid equilibria, [29] thus indicating that the interaction-energy parameters could be used to characterize the microstructure of the system.B yc omparing the interactionenergy parameters obtained from the three studied C sp 2ÀH (Table 1), the values of the interaction-energy parameters obtained from C2ÀHw as found to be slightly smaller than those obtained from C4ÀHa nd C5ÀHo ft he same system,w hich means that the hydrogen bonds between water and C2ÀHa re stronger than those between water and C4ÀHa nd C5ÀH; this finding is consistentw ith ap revious report. [12] However,f or the same system,t he differences between the values of the interaction-energy parameters obtained from the three studied C sp 2ÀHa re not very significant, thus indicating that the three studied C sp 2ÀHw ithin the same cation may have ad ifferent local composition in their immediate vicinity and the interactions between water and thet hree studied C sp 2ÀHa re all related to the microstructure of the system.T herefore, to express the microstructure of the studied systems as objectively and comprehensively as possible, the interactions of C4ÀHa nd C5ÀHa lso need to be considered, as well as the interaction of C2ÀH.…”