Excess Enthalpies Research Articles

Excess Enthalpies for Binary Mixtures of the Reactive System Acetic Acid + n-Butanol + n-Butyl Acetate + Water: Brief Data Review and Results at 313.15 K and Atmospheric Pressure

The data on molar excess enthalpies, HmE, for the binary mixtures acetic acid + n-butanol, acetic acid + n-butyl acetate and n-butanol + n-butyl acetate at 313.15 K and atmospheric pressure were obtained with use of the C80 isothermal mixing calorimeter (Setaram). The correlation of the data was carried out using the NRTL model and Redlich-Kister equation. A comparative analysis with the literature data on all available binary subsystems of the quaternary system was carried out. Other thermodynamic properties (Cp,mE, SmE, ΔmixSm, GmE and ΔmixGm) of the binary systems were estimated using literature data and well-known formulas of classical thermodynamics.

Influence of physicochemical properties and structure of mixed solvents propylene glycol – macrogol 400 on their in vitro release

Aim. To study the density and dynamic viscosity of the mixed solvents propylene glycol (PG) – macrogol 400 (M400), to calculate their excess values and excess activation parameters of viscous flow, to evaluate the features of the structure of the mixed solvents and its influence on the in vitro release of PG and M400.
 Materials and methods. The mixed solvents PG - M400 were studied over the entire concentration range at temperatures from 293.15 to 313.15 K. The density and dynamic viscosity were determined, and the excess density, excess dynamic viscosity, activation parameters of viscous flow, and excess activation parameters of viscous flow were calculated. The in vitro release of PG and M400 from the mixed solvents was studied using vertical diffusion cells. The content of PG and M400 in the receptor medium was determined by gas chromatography using validated analytical procedures. The release rate, cumulative content, percentage of released PG or M400, coefficients of correlation and coefficients of determination were calculated.
 Results. The isotherms of excess density and excess dynamic viscosity of the mixed solvents PG-M400 pass through a maximum. The enthalpy makes the main contribution to the free activation energy of the viscous flow. The excess free energy is positive and has small values; the values of the excess entropy and excess enthalpy are negative, and the isotherms have the minimum at PG concentrations of 70‑75mol %. The release parameters of M400 are greater in binary mixtures where the M400 structure predominates. At PG content of ~75 mol %, the release parameters for PG and M400 are identical. With the increase in PG content above 75 mol %, when the PG structure predominates in the system, the release parameters of PG increase dramatically, and the release parameters of M400 decrease sharply.
 Conclusions. The structure of the binary system PG – M400 depends on its composition. Based on the isotherms of excess activation of viscous flow, it is possible to differentiate the areas where the structure of PG or the structure of M400 dominates, or the mixed structure of the binary solvent prevails. The in vitro release parameters for PG and M400 depend on the structure of the mixed solvents. The greatest difference in the release parameters of PG and M400 was observed in the area where the structure of PG dominates

Effect of molding history on molecular orientation relaxation during physical aging of polystyrene injection moldings

Abstract This work examined the effect of changing molding conditions on the physical aging of polystyrene injection moldings. First, we investigated the relationship between the molecular orientation and the molding conditions. The molecular orientation near the surface changed with changing injection rate, so we hypothesized that this molecular orientation might form during the filling stage. Because this molecular orientation did not relax under heat treatment below the glass transition temperature (T g), the oriented molecules near the surface were thought to be elongated owing to the high strain rate during the filling stage. On the other hand, the molecular orientation in the core layer changed with changing holding pressure and relaxed under heat treatment below T g. Thus, the molecules in the core layer might become oriented during the holding stage and not be elongated owing to the slow strain rate. Furthermore, the molecular orientation in the core layer decreased with increasing mold temperature, and the physical heat resistance improved with increasing mold temperature. Meanwhile, the excess enthalpy did not change with changing molding conditions. Therefore, the improvement in physical heat resistance with increasing mold temperature was likely caused by the decrease in the molecular orientation in the core layer. Analyzing the relaxation behavior of the molecular orientation suggested that increasing mold temperature reduced the number of oriented molecules with large deformation in the core layer.

Aromatic volatile organic compounds absorption with phenyl‐based deep eutectic solvents: A molecular thermodynamics and dynamics study

AbstractThe suitability of phenyl‐based deep eutectic solvents (DESs) as absorbents for toluene absorption was investigated by means of thermodynamic modeling and molecular dynamics (MD). The thermodynamic models perturbed‐chain statistical associating fluid theory (PC‐SAFT) and conductor‐like screening model for real solvents (COSMO‐RS) were used to predict the vapor–liquid equilibrium of DES–toluene systems. PC‐SAFT yielded quantitative results even without using any binary fitting parameters. Among the five DESs studied in this work, [TEBAC][PhOH] consisting of triethyl benzyl ammonium chloride (TEBAC) and phenol (PhOH), was considered as the most suitable absorbent. Systems with [TEBAC][PhOH] had lowest equilibrium pressures of the considered DES–toluene mixtures, the best thermodynamic characteristics (i.e., Henry's law constant, excess enthalpy, Gibbs free energy of solvation of toluene), and the highest self‐diffusion coefficient of toluene. The molecular‐level mechanism was explored by MD simulations, indicating that [TEBAC][PhOH] has the strongest interaction of DES–toluene compared to the other DESs under study. This work provides guidance to rationally design novel DESs for efficient aromatic volatile organic compounds absorption.

Assessing Solvate Prediction Approaches: A Case of Spironolactone

In silico methods for predicting solvate formation can guide and simplify solid form screening and solvent selection in crystallization processes. Solvates involve many complicated nonspecific interactions, making solvate prediction challenging. The applicability of three solvate prediction approaches to spironolactone (SPI) in 29 solvents was assessed, including thermodynamic excess enthalpy (Hex), hydrogen bond propensity (HBP), and a random forest model (RF). In experimental screening, 6 new solvates were identified and crystal structures of 5 solvates were revealed. Structural features, interaction calculations, and thermal analysis provided insights into the formation of SPI solvates. Not only strong hydrogen bonds but also weak interactions contribute significantly to the SPI channel and isolated site solvates. The Hex based on COSMO-RS theory (conductor-like screening model for real solvents) has a 65.5% success rate for SPI solvates prediction. The HBP can only be used for solvents with hydrogen bond donors with an 81% hit rate. The RF model shows a predictive success rate of 76.9% for unreported solvents. This work indicates it is difficult for these models to adequately predict solvate systems where multiple dominant interactions (such as hydrogen bonds, van der Waals forces, etc.) may be involved simultaneously. Using both COSMO-RS and HBP methods followed by the RF model may yield better results.

Thermodynamics of bicyclic compound + n-alkane mixtures

Mixtures formed by a cyclic molecule A, namely cyclohexane, or benzene, or bicyclohexyl ((1,1′-bi(cyclohexane)), or cis-decalin (cis-bicyclo[4.4.0]decane), or trans-decalin (trans-bicyclo[4.4.0]decane), or cyclohexylbenzene, or tetralin (1,2,3,4-tetrahydronaphthalene) and a n-alkane have been investigated by means of excess molar functions, enthalpies (HmE) and volumes (VmE), available in the literature, and of isochoric excess properties determined in this work, internal energies (UVmE) and heat capacities (CVmE). The behaviour of the systems with respect to the GmE(excess molar Gibbs energy) vs. HmE is discussed. The mixtures have been also studied using the zeroth approximation of DISQUAC and the Flory model. Dispersive interactions are dominant in the considered systems. The HmE values increase with n, the number of C atoms in the n-alkane, along each homologous series. Mixtures containing shorter n-alkanes and a bicyclic compound are characterized by large negative VmE values, which remark the existence of large structural effects. It is shown that longer n-alkanes are poorer breakers of the A-A interactions, which leads to decreased values of UVmE when n increases in systems with a given cyclic compound. The disruption of the short orientational order of longer n-alkanes by the A molecules lead to increased values ofUVmE. This effect is predominant in systems with cyclohexane, or benzene from n = 8, and UVmE decreases up to this alkane and then increases. However, the mentioned effect seems to be only predominant in systems with a bicyclic compound for n = 16. Thus, UVmE decreases up to n = 12 and increases for n = 16. The different behaviour of the treated systems is described by the Flory model through a X12 parameter which increases with n in solutions with cyclohexane or benzene, and that changes similarly to UVmE in the remainder solutions. In terms of DISQUAC, the enthalpic interaction parameter for the aromatic/aliphatic contact is independent of the n-alkane in systems with tetralin. For solutions with bicyclohexyl or cis-decalin, the variation with n of the mentioned parameter for the aliphatic/cyclic contact is similar to that observed for cyclohexane systems.

Multiscale molecular simulations for the solvation of lignin in ionic liquids

Lignin, the second most abundant biopolymer found in nature, has emerged as a potential source of sustainable fuels, chemicals, and materials. Finding suitable solvents, as well as technologies for efficient and affordable lignin dissolution and depolymerization, are major obstacles in the conversion of lignin to value-added products. Certain ionic liquids (ILs) are capable of dissolving and depolymerizing lignin but designing and developing an effective IL for lignin dissolution remains quite challenging. To address this issue, the COnductor-like Screening MOdel for Real Solvents (COSMO-RS) model was used to screen 5670 ILs by computing logarithmic activity coefficients (ln(γ)) and excess enthalpies (HE) of lignin, respectively. Based on the COSMO-RS computed thermodynamic properties (ln(γ) and HE) of lignin, anions such as acetate, methyl carbonate, octanoate, glycinate, alaninate, and lysinate in combination with cations like tetraalkylammonium, tetraalkylphosphonium, and pyridinium are predicted to be suitable solvents for lignin dissolution. The dissolution properties such as interaction energy between anion and cation, viscosity, Hansen solubility parameters, dissociation constants, and Kamlet–Taft parameters of selected ILs were evaluated to assess their propensity for lignin dissolution. Furthermore, molecular dynamics (MD) simulations were performed to understand the structural and dynamic properties of tetrabutylammonium [TBA]+-based ILs and lignin mixtures and to shed light on the mechanisms involved in lignin dissolution. MD simulation results suggested [TBA]+-based ILs have the potential to dissolve lignin because of their higher contact probability and interaction energies with lignin when compared to cholinium lysinate.

Complex coupling between surface charge and thermo-osmotic phenomena.

Thermo-osmotic flows, generated at liquid-solid interfaces by thermal gradients, can be used to produce electric currents from waste heat on charged surfaces. The two key parameters controlling the thermo-osmotic current are the surface charge and the interfacial enthalpy excess due to liquid-solid interactions. While it has been shown that the contribution from water to the enthalpy excess can be crucial, how this contribution is affected by surface charge remained to be understood. Here, we start by discussing how thermo-osmotic flows and induced electric currents are related to the interfacial enthalpy excess. We then use molecular dynamics simulations to investigate the impact of surface charge on the interfacial enthalpy excess, for different distributions of the surface charge, and two different wetting conditions. We observe that surface charge has a strong impact on enthalpy excess, and that the dependence of enthalpy excess on surface charge depends largely on its spatial distribution. In contrast, wetting has a very small impact on the charge-enthalpy coupling. We rationalize the results with simple analytical models, and explore their consequences for thermo-osmotic phenomena. Overall, this work provides guidelines to search for systems providing optimal waste heat recovery performance.

Thermodynamically consistent vapor-liquid equilibrium modelling with artificial neural networks

An integration of artificial neural networks (ANNs) and thermodynamics through the application of Neural Network Programming (NNP) is proposed. Thermodynamic consistency is achieved because the thermodynamic relationships and constraints are transcribed into a specially crafted ANN. Moreover, the developed models allow predicting and extrapolating the model outside the experimental data boundaries. The Wilson and NRTL models are used as case studies. Modifications to these models based on sigmoid functions are rigorously assessed in order to perform the simultaneous modelling of VLE and excess enthalpy. The automatic differentiation together with the ANN optimization algorithms can find sets of parameters that are better than the ones obtained with traditional gradient-based optimizers. The frequently disregarded concepts of thermodynamic modelling with ANNs are discussed in-depth. A mathematical analysis of the impossibility of typical fully connected ANNs to formulate thermodynamically consistent equilibrium models is discussed and their use is discouraged (e.g., VLE, LLE, or adsorption.).

MODES OF ADHESIVE BONDING LAYER FORMATION DURING ROLL MOTION IN THE PROCESS OF SHEET LAMINATION

Novel technologies for the synthesis and processing of materials and products based on these materials, such as additive manufacturing, require the use of mathematical modeling to study the accompanying physical and chemical phenomena. These technologies include sheet lamination, which today has a variety of applications and numerous modifications. This article presents a model of adhesion layer formation in the creation of multilayer composites, which is controlled by a hot roller moving along the surface of the top layer. The dynamics of reagent heating depends on the thermal properties and sizes of all layers, the temperature of the roller, and its pressure against the surface, with characteristic times and spatial scales for different processes. The transition to dimensionless variables allowed the identification of dimensionless complexes to determine different modes of development of the adhesion layer synthesis process. Based on the combustion theory and non-equilibrium thermodynamics, new criteria of the process initiation and transition to a quasi-stationary mode were elaborated. The behavior of various thermodynamic quantities was analyzed in detail, including heat storage in the heated layer, enthalpy excess, and entropy production. The reaction zone is wide in most cases. The dependences of the half-conversion time on the model parameters are plotted for a finite layer size. This is a new characteristic for sheet lamination technology. A controlled mode, a fast bulk synthesis mode, a slow transformation mode maintained by the heat stored in the inert materials, and a quasi-stationary mode are identified. Criteria were established for different modes of reactions under conjugate heat exchange conditions.

Measurement and prediction of isothermal vapor–liquid equilibrium of α-pinene + camphene/longifolene + abietic acid + palustric acid + neoabietic acid systems

The vapor-liquid equilibrium (VLE) data of α-pinene + camphene + [abietic acid + palustric acid + neoabietic acid] and α-pinene + longifolene + [abietic acid + palustric acid + neoabietic acid] systems at 313.15 K, 333.15 K and 358.15 K were measured by headspace gas chromatography (HSGC). These data was compared with the predictions value by Conductor-like screening model for realistic solvation (COSMO-RS). Moreover, the calculated data of COSMO-RS and NRTL（Nationally Recognized Testing Laboratory） models showed good agreement with the experimental data. It was found that the three resin acids inhibits the volatility of α-pinene, camphene and longifolene and resulted in the decrease of total pressure. Moreover, H E (HB) contributes the most to the excess enthalpy and the hydrogen bonding interaction is the dominant intermolecular force of α-pinene, camphene and longifolene with the three resin acids. In addition, the geometric structures optimization and binding energy were obtained by the DFT to further illustrate the hydrogen bonding interaction and the effects of the addition of the three resin acids on the isothermal VLE.

Measurements and correlation of activity coefficients at infinite dilution for organic solutes in 1-heptyl-3-methylimidazolium chloride

This work is a continuation of our studies on the determination of activity coefficients at infinite dilution (γi∞) for organic solutes (i) in ionic liquids (ILs) and their use in separation processes. The values of γi∞ for 31 organic solutes including alkanes, cycloalkanes, 1,4-dioxane, aromatic hydrocarbons, cyclohexene, chloromethanes, acetonitrile, acetone, tetrahydrofuran, ethyl acetate and alcohols in the IL 1-heptyl-3-methylimidazolium chloride ([C7MIm]Cl) at six temperatures in range of (313.15–363.15) K were determined by gas-liquid chromatography (GLC). The density of [C7MIm]Cl as a function of temperature at pressure p= 101.33 kPa was measured and the values of gas-liquid partition coefficients (KL) were obtained. The linear relationship between lnγi∞ and 1/T was fitted by the Gibbs-Helmholtz equation. The molar excess thermodynamic functions including the infinite dilution partial molar excess Gibbs free energies (G¯iE,∞), partial molar excess enthalpies (H¯iE,∞) and entropies (TrefS¯iE,∞) at Tref = 298.15 K were calculated. In addition, the solubility parameters (δi) of [C7MIm]Cl were obtained from the regular solution theory combined with Flory “combinatorial” equation. The interaction between the solute and the IL was quantified based on the linear free energy relationship (LFER) model. The infinite dilution selectivity coefficients (Sij∞) of n-hexane (i)/benzene (j) and cyclohexane (i)/benzene (j) were calculated at T = 323.15 K from γi∞ and compared to literature values for [Cl]-based ILs for the same separation problems.

Investigation of structure and properties of polymerizable deep eutectic solvent based on choline chloride and acrylic acid

Deep eutectic solvents (DESs) are multi-component solvents appearing in a broad range of applications. The next necessary step for the development of new DESs is understanding the molecular mechanisms of DES formation and the interactions that determine its structure and properties. In this work, we use multiscale simulations supported by experiments to investigate the detailed structure and properties of polymerizable DESs based on choline chloride and acrylic acid as a basis for creating inks for 3D printing. Thermodynamic and structural analyses show the physical mechanisms of DES formation in these materials: due to the significant size difference between the acrylic acid and choline ions, and favorable interactions between acrylic acid and the Cl- ions, the acrylic acid molecules are able to incorporate into the free spaces of the first coordination shells of the Cl- ions. As a consequence, the mixture has less volume than its individual components and this excess volume determines the negative value of the enthalpy of mixing. Structurally, the mixture is a network with the Cl- ions as nodes connecting the other DES components. This was confirmed by both the FTIR experiments and the atomistic MD simulations. The calculations show the necessity of correct accounting of excess enthalpy and entropy for determining DESs structures and other properties.

Thermodynamic modeling of MDEA(aq)-NH3(aq)-K2CO3(aq)-CO2(aq) using the Extended UNIQUAC model

The development of advanced processes for carbon dioxide capture requires reliable thermodynamic models to ensure accurate process design. This work presents an optimized parameter set of the Extended UNIQUAC model for advanced mixed solvent solutions containing CO2-MDEA-NH3-K2CO3 in water. The model was parameterized using vapor–liquid equilibrium, pure component saturation pressure, excess enthalpy, heat of absorption, molar heat capacity, apparent molar heat capacity, and solid–liquid equilibrium. These thermal and equilibrium properties cover temperatures between 253.6K to 600K and pressures up to 75.6bar. The current model represents an extension of previous versions that were suitable for modeling aqueous NH3 and K2CO3 solutions. This parametrization accounts for molecular interactions between MDEA and these two components, which allows for the design of advanced capture processes. This paper demonstrates that the new model parameters are valid within the range of operational conditions typically found in CO2 capture processes.

Solubility study and thermodynamic modelling of succinic acid and fumaric acid in bio-based solvents

The solubility and involved energies of organic acids in green solvents are relevant to the design of sustainable biorefinery downstream processes. In this work, the solubility of two important bio-based organic acids such as succinic acid and fumaric acid, in water and four bio-based solvents (i.e., ethyl acetate, 1,8-cineole, cyclopentyl methyl ether, and 2-methyl tetrahydrofuran) were measured within a temperature range of [283 – 313] K. A gravimetric methodology was adopted, previously validated using the organic acid aqueous solubilities available in the literature. The reported data present an average estimated uncertainty of measurement, with a level of confidence of 95%, of 5.2·10-4 mol·mol−1. Experimental results were correlated with the van’t Hoff equation, and the Buchowski–Ksiazaczak λh model, where the root mean squared deviations were <3.9·10-4 for all systems. From the experimental data and the COSMO-RS molecular simulation method, the solid–liquid equilibria were modelled to estimate the excess energies and the solute activity coefficients of the saturated solutions. Excess enthalpy contribution analysis shows that attractive hydrogen-bonding interactions between the organic acids and the green solvents drive the dissolution phenomena. The magnitude of the hydrogen-bonding interactions increases with temperature for all systems, agreeing with the observed solubility trends. The organic acid energies of solution were estimated from the van’t Hoff equation, demonstrating an enthalpy–entropy compensation effect. The energetic analysis shows that the dissolution phenomenon is an enthalpy-driven process for fumaric acid, whereas no predominant effect is observed for succinic acid.

MD simulations explain the excess molar enthalpies in pseudo-binary mixtures of a choline chloride-based deep eutectic solvent with water or methanol.

The addition of molecular liquid cosolvents to choline chloride (ChCl)-based deep eutectic solvents (DESs) is increasingly investigated for reducing the inherently high bulk viscosities of the latter, which represent a major obstacle for potential industrial applications. The molar enthalpy of mixing, often referred to as excess molar enthalpy H E-a property reflecting changes in intermolecular interactions upon mixing-of the well-known ChCl/ethylene glycol (1:2 molar ratio) DES mixed with either water or methanol was recently found to be of opposite sign at 308.15K: Mixing of the DES with water is strongly exothermic, while methanol mixtures are endothermic over the entire mixture composition range. Knowledge of molecular-level liquid structural changes in the DES following cosolvent addition is expected to be important when selecting such "pseudo-binary" mixtures for specific applications, e.g., solvents. With the aim of understanding the reason for the different behavior of selected DES/water or methanol mixtures, we performed classical MD computer simulations to study the changes in intermolecular interactions thought to be responsible for the observed H E sign difference. Excess molar enthalpies computed from our simulations reproduce, for the first time, the experimental sign difference and composition dependence of the property. We performed a structural analysis of simulation configurations, revealing an intriguing difference in the interaction modes of the two cosolvents with the DES chloride anion: water molecules insert between neighboring chloride anions, forming ionic hydrogen-bonded bridges that draw the anions closer, whereas dilution of the DES with methanol results in increased interionic separation. Moreover, the simulated DES/water mixtures were found to contain extended hydrogen-bonded structures containing water-bridged chloride pair arrangements, the presence of which may have important implications for solvent applications.

A modified electrolyte non‐random two‐liquid model with analytical expression for excess enthalpy: Application to theMEA‐H2O‐CO2system

AbstractAccurate thermodynamic properties of electrolyte systems are critical for the design and operation of many chemical processes. A comprehensive description of the thermodynamic framework for multielectrolyte mixed solvent systems is presented, where the parameter structure of the symmetric electrolyte‐non‐random two liquid (e‐NRTL) model is reformulated and a thermodynamically consistent and analytically derived formulation for the excess enthalpy is developed from the e‐NRTL model. The refined parameter structure of the e‐NRTL model avoids numerical singularities of the analytical formulation for the excess enthalpy in the absence of ionic species and extends the derived excess enthalpy formulation to non‐electrolyte systems. The thermodynamic framework is demonstrated for the MEA‐H2O‐CO2case study using experimental data on thermodynamic quantities for the binary MEA‐H2O system and the ternary MEA‐H2O‐CO2system. The model is implemented in Pyomo and will be available for release in the Institute for the Design of Advanced Energy Systems (IDAES) computational platform.

Measurement and correlation of thermodynamics properties of aqueous solutions containing glycols. Part II: Excess molar enthalpy

In this work, excess molar enthalpies of binary liquid mixtures of {water + ethanol, or + ethylene glycol, or + diethylene glycol, or + triethylene glycol, or + poly(ethylene glycol) 200, or + poly(ethylene glycol)300, or + poly(ethylene glycol)400, or + poly(ethylene glycol)600, or + glycerol} have been determined as a function of composition using a microcalorimeter Thermal Activity Monitor (2277, Thermometric) at 298.15 K and atmospheric pressure. The results were fitted by the Myers-Scott equation, as a function of mole fraction. The values of excess molar enthalpies were exothermic and large. The excess partial molar enthalpies and excess partial molar enthalpies at infinite dilution were calculated. Moreover, the experimental results were used to test the applicability of the Wilson, NRTL and UNIQUAC models. The results of excess molar enthalpies were discussed in terms of molecular interactions.

Excess properties of mixtures containing 2-(2-ethoxyethoxy)ethanol, methylcyclohexane, cyclohexane and 1‑hexene as fuel representative

The experimental and modelling excess enthalpy, HE, data for the following binary and ternary mixtures: methylcyclohexane (1) + 1‑hexene (2), 2-(2-ethoxyethoxy)ethanol (1) + 1‑hexene (2) + cyclohexane (3), and 2-(2-ethoxyethoxy)ethanol (1) + methylcyclohexane (2) + 1‑hexene (3) are studied in this work at two different temperatures (298.15 and 313.15) K and 0.1 MPa. To measure the HE of the studied binary and ternary mixtures, a quasi-isothermal flow calorimeter was used. All the binary and ternary mixtures present an endothermic behavior at the chosen temperatures. Measured data of HE were correlated using modified Redlich-Kister equation, NRTL and UNIQUAC models.

Vapor-liquid equilibrium experiment and prediction of excess property of new working pair CO2-[BMP][Tf2N] in absorption refrigeration system: Expérience d'équilibre vapeur-liquide et prédiction de la propriété excédentaire de la nouvelle paire de travail CO2-[BMP][Tf2N] dans un système de réfrigération à absorption

Solubility of CO2 in ionic liquids (ILs) is of great importance in absorption refrigeration system as new working pairs. Vapor-liquid equilibrium (VLE) of CO2 in [BMP][Tf2N] (1-butyl-1-methyl-pyrrolidine bis(trifluoromethylsulfonyl)imide) is carried out experimentally using the experiment system at temperature range 303.15 K-363.15 K. The experimental results show that the solubility of CO2 in [BMP][Tf2N] can reach up to 0.1235–0.5324 (molar fraction) within temperature range 283.15∼363.15 K and pressure range of 0.2∼5 MPa. The solubility of CO2 in [BMP][Tf2N] increases with increase of temperature and pressure. The VLE data of CO2-[BMP][Tf2N] binary system is correlated with two models (SRK equation of state +WS mixing rule +UNIFAC activity coefficient model and PR equation of state +WS mixing rule +UNIFAC activity coefficient model). The excess Gibbs free energy (GE), excess enthalpy (HE) and excess entropy (SE) of the system are obtained and the interaction parameters kij is regressed based on the VLE of CO2-[BMP][Tf2N] binary system. The variation trend of GE, HE and SE are obtained with temperature, pressure and molar fraction of CO2. The calculation results show that the accuracy of SRK equation of state is slightly higher than that of PR equation of state in CO2-[BMP][Tf2N] binary system. The accuracy of SRK equation of state and PR equation of state decreases with increase of temperature and pressure.