•Isobaric VLE data of three binary systems containing methyl myristate were measured.•The new data are useful for the exploitation of diesel/biodiesel blended fuel.•The reliability of the experimental data were confirmed by the van Ness method.•The VLE data were correlated well by the activity coefficient models.In this work, new isobaric vapor–liquid equilibrium (VLE) data for the three binary mixtures (n-tetradecane + methyl myristate), (n-pentadecane + methyl myristate) and (n-hexadecane + methyl myristate) have been determined at 5.00 kPa by a Rose still. The three binary systems exhibit positive deviations and do not have an azeotropic point. All the experimental data were confirmed to be thermodynamic consistent using the van Ness method. The NRTL, UNIQUAC, and Wilson activity coefficient models were applied to regress the experimental VLE data and the new binary interaction parameters for the three models were obtained. The correlated values of the three models were compared with the measured data, the average absolute deviations of the temperatures and the vapor compositions for all the systems were less than 0.23 K and 0.0024, respectively. Therefore, the three activity coefficient models are suitable for all the three binary systems.

•Three VLE ternary systems were measured and correlated at high temperatures and pressures.•The content of methanol in liquid phase increase, while glycerol and FAME decrease with pressure.•The mutual solubility in vapor phase decreased with molecular chain length of FAME.•VLE data was regressed by different EOS. RKS-ASPEN EOS can correlate accurately.The phase behaviors for three ternary systems (methanol + glycerol + methyl laurate/methyl myristate/methyl palmitate) were studied at elevated temperatures (about 493.0 K, 523.0 K) and pressures by a flow-type method. The results demonstrated that the mole fractions of methanol in liquid phase increase and the mole fractions of glycerol and FAME decrease with increasing pressure. The influences of FAME molecular chain length on mutual solubility between methanol, glycerol and FAME in vapor phase were discussed. The experimental data were regressed by Redlich-Kwong-Soave equation of state (RKS EOS), RKS EOS combined with Boston and Mathias function (RKS-BM EOS) and Redlich-Kwong-Soave Aspen equations of state (RKS-Aspen EOS) with van der Waals (vdW) mixing rule. The correlated results with RKS-Aspen EOS are more accurate than other EOSs. The vapor-liquid equilibria (VLE) experimental data can be employed for designing the methanol process and phase separation in biodiesel production technology.The phase equilibria data of three ternary systems at elevated temperatures (about 493.0 K, 523.0 K) and pressures were measured by a flow-type method. The experimental data were regressed by Redlich-Kwong-Soave equation of state (RKS EOS), RKS EOS combined with Boston and Mathias function (RKS-BM EOS) and Redlich-Kwong-Soave Aspen equations of state (RKS-Aspen EOS) with van der Waals (vdW) mixing rule.

Water is the most abundant compound inherently existing in bio-oils. Thus understanding the role of water within bio-oils upgrading process is essential for future engineering scale-up design. In this study, furfural was chosen as bio-oils model compound, and the catalytic hydrogenation of furfural over commercial 5%, Ru/C catalyst was firstly investigated in a series of gradient variable water/ethanol mixture solvents. Water had a significant effect on the distribution of product yields. The dominant reaction pathways varied with the water contents in the water/ethanol mixture solvents. Typically, when ethanol was used as the solvent, the main products were obtained by the hydrogenation of carbonyl group or furan ring. When pure water was used as the solvent, the rearrangement reaction of furfural to cyclopentanone should be selectively promoted theoretically. However, serious polymerization and resinification were observed herein in catalytic hydrogenation system of pure water. The catalyst surface was modified by the water-insoluble polymers, and consequently, a relative low yield of cyclopentanone was obtained. A plausible multiple competitive reaction mechanism between polymerization reaction and the hydrogenation of furfural was suggested in this study. Characterizations(TG,FT-IR,SEM)were employed to analyze and explain our experiments.

•LLE data containing n-alkane, fatty acid methyl ester and methanol were measured.•The experimental data were well modeled using NRTL and UNIFAC-Dortmund models.•The new and reliable model parameters were obtained.•Phase chart for the diesel/biodiesel/methanol blends was successfully simulated.In order to obtain the solubility values for the diesel/biodiesel/methanol blends and prepare the homogeneous single blended fuels, biodiesel or diesel was composed approximately of a series of model compounds and the liquid–liquid equilibrium (LLE) data for the seven ternary and one quaternary systems involving in n-alkane, fatty acid methyl ester and methanol have been measured and performed thermodynamic modeling. The experimental data were correlated by NRTL model and UNIFAC-Dortmund model with a good accuracy. The new parameters of NRTL and UNIFAC-Dortmund models were obtained systematically and they were tested to be reliable for the (diesel + biodiesel + methanol) system through the prediction of some experimental and literature data. Meanwhile, the phase chart for the (diesel + biodiesel + methanol) mixture was successfully simulated using Aspen Plus software based on the obtained NRTL and UNIFAC-Dortmund models parameters, which was applied to investigate the compatibility of biodiesel/diesel/methanol blended fuel. In this work, the diesel/biodiesel/methanol blended fuel containing 30% biodiesel is likely to be border-line in terms of homogeneous system.

In this work, liquid–liquid equilibrium (LLE) data for the two ternary systems methyl laurate + ethanol + glycerol and methyl myristate + ethanol + glycerol were measured at 318.15 K and 333.15 K under atmospheric pressure. The reliability of the experimental tie-line data was checked by the Othmer–Tobias correlation. The LLE experimental data were correlated with the nonrandom two-liquid (NRTL) model, and the binary interaction parameters were regressed by the data fitting. The correlated results agreed satisfactorily with the experimental results.

Ionic liquids have attracted much attention in past decade for their unique properties. The density is an important property in industrial application, however the density data are relatively scarce compared with the great number of ILs. The quantitative structure property relationship (QSPR) and group contribution method (GCM) have been used for predicting ILs density. However, the accuracy of QSPR is not as good as that of GCM. In this work, a desirable QSPR model was developed to estimate ILs density. The general topological indexes (TIs) proposed by our research group were used to develop the QSPR model, which was on the basis of 5948 experimental data points for 188 ILs. The collected data are in the range of temperature (253.15–473.15) K and pressure (0.1–250) MPa. The correlation coefficient (R2) and the overall average absolute deviation are 0.998 and 0.422 %, respectively.

Liquid-liquid equilibrium data of two ternary systems methyl palmitate+ethanol+glycerol and methyl stearate+ethanol+glycerol at(318.2 and 333.2)K and atmospheric pressure were measured. The values of distribution coefficient and selectivity were calculated, which indicates that glycerol can be separated from fatty acid ester by using ethanol as an extraction solvent. The consistency of the isothermal tie-line data were checked by the Othmer-Tobias equation. The correlation coefficients R2 are higher than 0.993,9 for all the fitted curves. The NRTL activity coefficient model was applied to the correlation of the measured tie-line data. The root mean square deviation(RMSD)values are less than 0.007 for all the systems, which shows a good predictive capability of this model for such systems.

Miscible gas flooding is one of the most effective methods for enhanced oil recovery (EOR). A key and important parameter in designing an efficient miscible gas flooding is the minimum miscibility pressure (MMP). It is very essential to determine and predict gas–oil MMP for EOR technology. In this work, both the experiment and correlation approaches for obtaining gas–oil MMP were studied. Experimentally, a set of apparatus with the vanishing interfacial tension (VIT) technique was set up and utilized to determine the gas–oil MMP for three different kinds of injection gas. Theoretically, a new model was proposed to predict the gas–oil MMP. A total of 156 experimental MMP data were achieved from this work and literature was used to train and test the model. The average absolute relative deviations (AARD%) of the training set for pure CO2, CO2 mole fraction less than 0.5 (xCO2 < 0.5) and CO2 mole fraction larger than 0.5 (xCO2 > 0.5) in the injection gas are 5.85%, 4.06% and 6.49%, respectively. The AARD% of the testing set are 2.08%, 2.97% and 5.26%, respectively. The model is applied to calculate the gas–oil MMP in different CO2 purity flooding with CO2 mole fraction in the injection gas from 0.0352 to 1.

The isobaric vapor–liquid equilibrium (VLE) data were measured for the binary system (ethane-1,2-diol + butan-1,2-diol) at (20, 30, and 40) kPa using a modified dynamic recirculating still. The thermodynamic consistency of the experimental data was confirmed using the Herington and van Ness semiempirical method. The Wilson and universal quasichemical (UNIQUAC) models were used to correlate the activity coefficients with the liquid-phase composition. The average absolute deviation of the bubble-point temperature and vapor molar fraction for all of the systems obtained from the Wilson and UNIQUAC models are less than 0.18 K and 0.0011, respectively. Furthermore, the binary system (ethane-1,2-diol + butan-1,2-diol) exhibited azeotropic behavior. In addition, the data were calculated using the UNIFAC (Do) model (modified UNIFAC model) in which ethane-1,2-diol was treated as two groups (−CH2OH), and butan-1,2-diol was split to four groups (−CH2OH, −CHOH, −CH2, and −CH3). The new group-interaction parameter for CH2–CH2OH was obtained and used to estimate the VLE data for the binary system (butan-2-ol + butan-1-ol) at 101.3 kPa. The results are consistent with those of the literature data.

The conversion of cellulose into valuable chemicals to deal with the depletion of fossil fuel has got much attention. Completing the hydrolysis of cellulose under mild conditions is the key step. In this study, six kinds of SO3H-functionalized acidic ionic liquids were used as acid catalyst to promote the hydrolysis of cellulose in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). All of them were efficient for the hydrolysis of cellulose, with the maximum total reducing sugars (TRS) yields over 83% at 100 °C. Acidic ionic liquids with analogous structures showed similar catalytic activities. Triethyl-(3-sulfo-propyl)-ammonium hydrogen sulfate (IL-5 in this study) was the optimum ionic liquid for cellulose hydrolysis, with the maximum TRS yield at 100 °C up to 99% when the dosage used was 0.2 g. In addition, the water in [BMIM]Cl had negative effect on cellulose hydrolysis. Therefore, controlling the content of water in a comparatively low level is quite necessary.Highlights► Six kinds of acidic ionic liquids were used to promote the hydrolysis of cellulose. ► The main factors influencing the hydrolysis of cellulose were investigated. ► Acidic ionic liquids with analogous structures showed similar catalytic activities. ► The water in solvent [BMIM]Cl had negative effect on the TRS yield.

•A general topological index was proposed based on atom characters and position.•A QSPR model was developed to predict the glass transition temperatures of ILs.•A topological index was generated from anion and cation.Based on the general topological index (TI) proposed in our previous work, a Quantitative Structure–Property Relationship (QSPR) model was developed to predict the glass transition temperatures of ionic liquids (ILs). Because ILs are a class of molten salts which are composed entirely of cations and anions, in general, the descriptors for ILs are calculated from cations and anions separately and the interaction between them is neglected. In this study, except the two sets of TIs generated from cation and anion, a third TI was used to depict the interaction of anion and cation. The QSPR model is based on five kinds of ILs, which are imidazolium (Im), pyridinium (Py), ammonium (Am), sulfonium (Su), triazolium (Tr). The regression coefficient (R2) and the overall average absolute relative deviation (AARD) are 0.894 and 3.32%, respectively.

•A general topological index was proposed based on atom characters and position.•The topological index was extended for predicting melting points of ionic liquids.•A topological index was generated from anion and cation.A Quantitative Structure Property Relationship (QSPR) model was developed to predict the melting points of ionic liquids (ILs) with diverse classes of cations and anions. The QSPR model was based on the general topological index (TI) proposed in our previous work. The TI was successfully used for the prediction of the decomposition temperature of ILs and the toxicity of ILs in acetylcholine esterase and Leukemia Rat Cell Line. ILs are a class of molten salts which are composed entirely of cations and anions, therefore the descriptors for ILs are generally calculated from cations and anions separately and the interaction between them is neglected. In this study, besides the two sets of TIs generated from cations and anions, a third TI was used to depict the interaction of anions and cations. The QSPR model is on the base of eight kinds of ILs, which are imidazolium, benzimidazolium, pyridinium, pyrrolidinium, ammonium, sulfonium, triazolium and guanidinium. The regression coefficient (R2) and the overall average absolute deviation (AAD) are 0.778 and 7.20%, respectively.

Cellulose resource has got much attention as a promising replacement of fossil fuel. The hydrolysis of cellulose is the key step to chemical product and liquid transportation fuel. In this paper a serials of chloride, acetate, and formate based ionic liquids were used as solvents to dissolve cellulose. The cellulose regenerated from ILs was characterized by FTIR and X-ray powder diffraction. From the characterization and analysis, it was found that the original close and compact structure has changed a lot. After enzymatic hydrolysis, different kinds of ionic liquids (ILs) have different yields of the reducing sugar (TRS). They are 100%, 90.72%, and 88.92% from 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), 1-butyl-3-methylimidazolium formate ([BMIM][HCOO]) respectively after enzymatic hydrolysis at 50 °C for 5 h. The results indicated that the yields and the hydrolysis rates were improved apparently after ILs pretreatment comparing with the untreated substrates.Highlights► The systemic study of chloride, acetate and formate based ionic liquids supplied more choices for cellulose hydrolysis. ► Kinds of factors affecting the hydrolysis rate have been considered. ► The structure of regenerated cellulose and the experimental results have been given reasonable and more detailed explanations.

On the basis of the new topological index (TI) proposed in our previous work, a multiple linear regression (MLR) model was developed for predicting the toxicity of ionic liquids (ILs) in Leukemia Rat Cell Line (log EC50 IPC-81). The TI is derived from atom characters (e.g., atom radius, atom electronegativity, etc.) and atom position in the hydrogen-suppressed molecule structure. Because ILs are composed entirely of cations and anions, the TIs are calculated from cation and anion, respectively. A third TI was also proposed to depict the interaction of anion and cation. The toxicity of 173 ILs, which are based on imidazolium (Im), pyridinium (Py), pyrrolidinium (Pyr), ammonium (Am), phosphonium (Ph), quinolinium (Qu), piperidinium (Pi), and morpholinium (Mo), was calculated by the model. The regression coefficient (R2) and the overall average absolute error (AAE) are 0.938 and 0.226, respectively.

Isobaric vapor–liquid equilibrium (VLE) data for thiophene with four different FCC gasoline compounds (2,3-dimethyl-2-butene, n-heptane, 2-methylbutane and 2,3-dimethyl-1-butene) were measured at 101.33 kPa with a circulation still. All the four binary systems exhibit positive deviations from ideal solution behavior. Especially, thiophene + n-heptane binary system exhibits maximum pressure homogeneous azeotrope at 356.33 K with the composition 0.8499 for thiophene. All the VLE measurements passed the thermodynamic consistency test. Wilson model was used to correlate the experimental VLE data. The infinite dilution activity coefficients for the systems were also presented. The experimental data of thiophene + 2,3-dimethyl-2-butene and thiophene + 2,3-dimethyl-1-butene were correlated by original UNIFAC and UNIFAC-Dortmund models. The interaction parameters of the binary pair C4H4S functional group and CC functional group for the two models were obtained and they were tested reliable by some literature data.Highlights► Isobaric vapor–liquid equilibrium for thiophene was measured with a circulation still. ► All the binary systems exhibited positive deviation from ideal system. ► The experimental data were correlated with the Wilson model. ► All VLE measurements passed the thermodynamic consistency test. ► The infinite dilution activity coefficients for the systems were also presented.

In this work a new topological index (TI) was proposed based on atom characteristics (e.g., atom radius, atom electronegativity, etc.) and atom positions in the hydrogen-suppressed molecule structure. Using the TIs, a multiple linear regression (MLR) model was developed for predicting the decomposition temperature (Td) of 158 ionic liquids (ILs), which are based on imidazolium, pyridinium, pyrrolidinium, ammonium, phosphonium, sulfonium, and guanidinium. Because ILs are a class of molten salts which are composed entirely of cations and anions, in general, the descriptors for ILs are calculated from cations and anions separately, and the interaction between them is neglected. In this study, except for the two sets of TIs generated from cations and anions, a third TI was proposed to depict the interaction of anions and cations. The regression coefficient (R2) and the overall average absolute deviation (AAD) are 0.893 and 3.07 %, respectively.

A new topological index (TI) was proposed based on atom characters (e.g., atom radius, atom electronegativity, etc.) and atom positions in the hydrogen-suppressed molecule structure in our previous work. In this work, the TI was used for predicting the toxicity of ILs in acetylcholin esterase (log EC50 AChE) by the multiple linear regression (MLR) method. For ILs composed entirely of cations and anions, the TIs are calculated from cations and anions, respectively. The 221 ILs used in the MLR model are based on imidazolium (Im), pyridinium (Pyi), pyrrolidinium (Pyo), ammonium (Am), phosphonium (Ph), quinolinium (Qu), piperidinium (Pi), and morpholinium (Mo). The regression coefficient (R2) and the overall average absolute error (AAE) are 0.877 and 0.153, respectively.

A falling-body viscometer was designed and manufactured to determine the densities and viscosities of liquids at high temperatures and pressures. The densities and viscosities for pure [bmim][PF6], [bmim][PF6] + ethanol, and [bmim][PF6] + benzene binary systems were determined in the temperature range of (313.2 to 413.2) K and in the pressure range of (0.1 to 25.0) MPa. The viscosities of [bmim][PF6] + ethanol, and [bmim][PF6] + benzene binary systems were correlated with temperature, pressure, and composition by correlation equations. The correlation coefficients (R) are 0.999 and 0.999 for [bmim][PF6] + ethanol and [bmim][PF6] + benzene systems, respectively.

In this work, liquid–liquid equilibria (LLE) for several binary systems of ionic liquids with aliphatic alcohols have been measured by the cloud point method from 280 K to the boiling point of the solvent. These binary systems include 1-hexyl-3-methylimidazolium tetrafluoroborate + 1-butanol/1-pentanol/1-hexanol/isobutanol and 1-octyl-3-methylimidazolium tetrafluoroborate + 1-butanol/1-pentanol/1-hexanol/1-octanol/isobutanol. The experimental data are analyzed, and some rules for the solubility of ILs are concluded, which can provide some instructions for the extraction and separation process. The equilibrium data are correlated by the nonrandom two-liquid (NRTL) model. The interaction parameters of the model for the systems are obtained. The minimum and maximum of the overall average deviation are 0.37 % and 2.67 %, respectively.

The Krupp−Koppers (K-K) extractive distillation method with N-formylmorpholine (NFM) as the solvent is one of the most important processes for catalytic hydrogen refining of rude benzene. To increase the capacity and selectivity of the solvent and decrease the ratio of solvent to feed in this process, ethylene glycol (EG), N,N-dimethylformamide (DMF), and N-methylpyrrolidone (NMP) were introduced as the cosolvent with NFM. The relative volatility of cyclohexane to benzene (α) at a certain Rstf (liquid-phase ratio of solvent to feed) was considered as a criterion of the performance of cosolvent. The vapor−liquid equilibrium (VLE) data for benzene + NFM, EG + NFM, benzene + cyclohexane + NFM, benzene + cyclohexane + NFM + EG, benzene + cyclohexane + NFM + DMF, and benzene + cyclohexane + NFM + NMP were measured at atmospheric pressure. VLE data of benzene + NFM, EG + NFM, benzene + cyclohexane + NFM, and benzene + cyclohexane + NFM + EG were calculated by the nonrandom two-liquid (NRTL) model. The average temperature deviations of benzene + cyclohexane + NFM and benzene + cyclohexane + NFM + EG systems are (1.40 and 3.19) K, respectively. The average deviations of the vapor-phase mole fraction of benzene are 0.030 and 0.066, respectively.

A new model is proposed here to estimate melting points of imidazolium and benzimidazolium ionic liquids (ILs) from chemical structures by using a group contribution method, which considers the contributions of normal groups, ionic groups, and characteristic factors of molecules. The melting points of ILs are fitted by the equation presented in this study. Thirty simple groups and three characteristic factors were defined in the model based on the optimization of property values of 155 ionic liquids. The average relative deviation in this work is less than 5.86%, and calculated values of an additional 35 ILs are compared with the values in the literature. The R2 for 190 ILs is about 0.8984. The results show that melting points of ILs determined by the method are accurate and thus the new model can be applied to predict melting points of ILs.

An apparatus used to measure vapor pressure of organic solvents was set up, and vapor pressure of mixture of ionic liquids ([BMIM][PF6] and [BMIM][BF4]) and aromatic compounds (benzene and thiophene), with mole fraction of organic solute from 0.1 to 0.75 was measured by using saturation vapor pressure method at temperature from 303 K to 343 K. Then NRTL equation was used to correlate the experimental data. The overall average relative deviation of activity coefficients for the whole system is 2.30%, which indicates that NTRL equation can be utilized to correlate vapor pressure of binary systems containing ionic liquids. The results show that ionic liquids can depress the volatility of aromatic compounds.

Densities of three binary systems, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) + ethanol, [BMIM][BF4] + benzene, and [BMIM][BF4] + acetonitrile, over the miscible composition range at T = (313.2 to 473.2) K were measured by means of a densimeter at elevated pressure up to 2.00 MPa. The total uncertainty of density was ± 0.0009 g·cm−3. The experimental densities were correlated by an empirical equation. The total average relative deviation (ARD) was 0.08 %, and then the excess molar volumes, VE, were calculated using the experimental densities. The uncertainty of the excess molar volumes was estimated to be about ± 0.008 cm3·mol−1.

Liquid−liquid equilibria for 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) or 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) + 1-propanol, + 1-butanol, and + 1-pentanol in the temperature range of (293.92 to 364.88) K and the solubility of benzene, toluene, and thiophene in [BMIM][PF6] and [BMIM][BF4] in the temperature range of (298.15 to 343.15) K have been measured using the cloud point method. The liquid−liquid equilibrium data were correlated by the nonrandom two-liquid (NRTL) equation, and the root-mean-square deviations of the mole fractions for [BMIM][PF6] or [BMIM][BF4] + 1-propanol, 1-butanol, and 1-pentanol are shown as follow: 0.0041, 0.0065, 0.0043, 0.0065, 0.0053, and 0.0019, respectively. In addition, it is found that the solubility of benzene, toluene, and thiophene in the ionic liquids was independent of temperature.

In this paper, an apparatus used to measure the surface tension at high temperature and elevated pressure was developed, based on the differential maximum bubble pressure method. As standard solvents, the surface tensions of methanol, ethanol, and benzyl benzoate were measured over a range of temperatures and pressures. The results were compared with the literature values, and the relative uncertainty of measurement is less than 2 %. The surface tensions of benzene, toluene, p-, o-, m-xylene, and the binary mixture of p-xylene + benzene were measured at 1.6 MPa, from (80 to 200) °C

Experimental liquid viscosities of pure compounds and their mixtures are needed for the design of chemical processes in heat and mass transfers or fluid mechanics. This paper is about partial work supported by SINOPEC (China Petroleum & Chemical Corporation). The results are related to the design calculation of synthesis of purified terephthalic acid (PTA). At temperature (313.15 to 473.15) K, the viscosities of pure p-xylene, pure acetic acid, and the p-xylene + acetic acid binary system of different concentrations were determined by a rolling-ball viscometer at pressures (0.10 to 3.20) MPa. Then, the viscosity data were fitted by a correlation equation. The AAD of the correlation is 1.21 %.

•Magnetic biochars were easily synthesized by pyrolyzing distillation residue.•Pyrolysis temperature showed a pronounced effect on magnetic biochar properties.•Adsorption of aromatic contaminants on magnetic biochars were investigated.•Adsorption mechanisms associated with biochar properties and target contaminants.The magnetic biochars were easily fabricated by thermal pyrolysis of Fe(NO3)3 and distillation residue derived from rice straw pyrolysis oil at 400, 600 and 800 °C. The effects of pyrolysis temperature on characteristics of magnetic biochars as well as adsorption capacity for aromatic contaminants (i.e., anisole, phenol and guaiacol) were investigated carefully. The degree of carbonization of magnetic biochars become higher as pyrolysis temperature increasing. The magnetic biochar reached the largest surface area and pore volume at the pyrolysis temperature of 600 °C due to pores blocking in biochar during pyrolysis at 800 °C. Based on batch adsorption experiments, the used adsorbent could be magnetically separated and the adsorption capacity of anisole on magnetic biochars was stronger than that of phenol and guaiacol. The properties of magnetic biochar, including surface area, pore volume, aromaticity, grapheme-like-structure and iron oxide (γ-Fe2O3) particles, showed pronounced effects on the adsorption performance of aromatic contaminants.

•LogEC50 of ILs on Vibrio fischeri is studied by topological method.•A general topological index was proposed.•A MLR model was developed to predict the toxicity of ionic liquids.As environmentally friendly solvents, ionic liquids (ILs) are unlikely to act as air contaminants or inhalation toxins resulting from their negligible vapor pressure and excellent thermal stability. However, they can be potential water contaminants because of their considerable solubility in water; therefore, a proper toxicological assessment of ILs is essential. The environmental fate of ILs is studied by quantitative structure–activity relationship (QSAR) method. A multiple linear regression (MLR) model is obtained by topological method using toxicity data of 157 ILs on Vibrio fischeri, which are composed of 74 cations and 22 anions. The topological index developed in our research group is used for predicting the V. fischeri toxicity for the first time. The MLR model is precise for estimating LogEC50 of ILs on V. fischeri with square of correlation coefficient (R2) = 0.908 and the average absolute error (AAE) = 0.278.

The viscosities of pure water, the acetic acid + water binary system, and the p-xylene + acetic acid + water ternary system at different concentrations were determined with a rolling-ball viscometer at temperatures from 313.15 to 473.15 K and pressures from 0.10 to 3.20 MPa. The viscosity data were fitted by a correlation equation for the estimation of the mixture viscosities. The average absolute deviations (AAD) of the correlation for binary and ternary systems are 2.48% and 1.77%, respectively.

•The IFTs of five systems (paraffins + CO2/(CO2+N2) mixture gas) were measured.•The relative Gibbs adsorption isotherm (Γij) was calculated by the measured IFTs.•The Γij changed with temperature and pressure were studied.•New correlations of paraffins IFTs were presented based on the experimental IFTs.Interfacial tension (IFT) is crucial for characterizing the phase and interphase behavior in the enhanced oil recovery (EOR) process. CO2 and N2 are commonly used as injection gases in the EOR process. In this work, an experimental apparatus using the pendent drop method was adopted to measure IFTs for the EOR process with different injection gases, temperatures (40.0–120.0 °C) and pressures (0.22–17.32 MPa). The relative Gibbs adsorption isotherm (Γij) of a species i on species j were calculated by the experimental IFTs. Theoretically, new correlations were proposed to predict paraffin IFTs for pure CO2 and mixture gas (CO2 + N2) injection. A total of 561 and 268 experimental IFTs were used to derive the correlations for pure CO2 and mixture gas injection, respectively. The square of correlation coefficient (R2), root mean square error (RMSE) and average absolute relative deviations (AARD) for pure CO2 were 0.9884, 0.58 and 5.45%, respectively. For the mixture gas injection, the R2, RMSE and AARD of the correlation were 0.9851, 0.57 and 4.47%, respectively.The IFTs of five paraffins with different injection gases were measured by pendent drop method. The relative Gibbs adsorption isotherm (Γ12) were calculated by experimental IFTs. The new correlations present IFT as a function of reservoir temperature, pressure, paraffin chain length and N2 mole fraction. The R2, RMSE and AARD of the correlation for the pure CO2 injection were 0.9884, 0.58 and 5.45%, respectively. The R2, RMSE and AARD of the correlation for the mixture gas injection were 0.9851, 0.57 and 4.47%, respectively. LOOCV and external validation methods were used to check the reliability and accuracy of the new correlations.