The UNIFAC model and the partition of alkyl and alkylphenol ethoxylate surfactants in the excess phases of middle phase microemulsions

Troncoso, Américo Boza; Acosta, Edgar

doi:10.1016/j.fluid.2015.03.035

Cited by 19 publications

(16 citation statements)

References 41 publications

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“…That is, the ACN is calculated based on molecular structure, while EACN is determined experimentally by fitting measured data of the oil to linear trends of optimum salinity with proxy fluids. Equations (17), which assumes spherical packing, can be simplified using I-ratio as…”

Section: Appendix 1: Derivation Of Modified Hld-nac Equations To Inclmentioning

confidence: 99%

“…Troncoso and Acosta [17] used the UNIFAC model to predict activity coefficients, HLD, and critical micelle concentration (CMC) for alkyl and alkylophenol ethoxylate surfactants. The universal relationship between HLD and activity coefficients is not determined yet, and the relationship changes based on oil, surfactant, and brine properties.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Robust Flash Calculation Algorithm for Microemulsion Phase Behavior

Khorsandi

Johns

2016

J Surfact & Detergents

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The HLD‐NAC model was recently modified to match and predict microemulsion phase behavior experimental data for Winsor type III regions. Until now, the HLD‐NAC model could not generate realistic phase behavior for type II− and type II+ two‐phase regions, leading to significant saturation and composition discontinuities when catastrophe theory is applied. These discontinuities lead to significant failures in modeling surfactant applications. We modify the HLD‐NAC equations to ensure consistency over the entire composition space including type II− and II+ regions. A robust and efficient algorithm is developed that always converges and provides continuous estimates with any formation variable of tie lines and triangles for all Winsor types. Discontinuities are eliminated and limiting tie lines near critical points are determined analytically. The tuning procedure is demonstrated using several sets of experimental data. Excellent predictability of tie lines and tie triangles, and solubilization ratios are shown.

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Section: Appendix 1: Derivation Of Modified Hld-nac Equations To Inclmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Robust Flash Calculation Algorithm for Microemulsion Phase Behavior

Khorsandi

Johns

2016

J Surfact & Detergents

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show abstract

“…7 Deeper insights into microemulsion systems and the physical-chemical properties involved are provided elsewhere, for example on the definition of Winsor types, fish tail points and fish diagrams, or equivalent alkane carbon numbers. 2,7,53 In short, a typical microemulsion system is composed of a less polar compound (usually called oil), a surfactant and water. After shaking this mixture in a test tube, three phases show up: an oil-rich phase at the top, an aqueous phase at the bottom, and a micellar, surfactant-rich phase in the middle.…”

Section: Microemulsion Systemsmentioning

confidence: 99%

“…4,5 Group contribution methods were used for the prediction of micellar and microemulsion properties, for example applying the universal functional activity coefficient model (UNIFAC). 6,7 Another interesting thermodynamic approach is the integrated free energy model (IFEM) for microemulsions. 1 Here, the Gibbs free energy is split up into a balance of different lipophilic and hydrophilic energetic contributions.…”

Section: Introductionmentioning

confidence: 99%

COSMOplex: self-consistent simulation of self-organizing inhomogeneous systems based on COSMO-RS

Klamt

Schwöbel²,

Huniar³

et al. 2019

Phys. Chem. Chem. Phys.

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“…Different methods to determine the surfactant concentration in water and oil at equilibrium conditions were applied depending on the investigated regime. Numerous studies discussed the partitioning in the pre-cmc regime [8,19,20,27,29], as well as in the post-cmc regime [20,[30][31][32][33]. In the pre-cmc regime, a proposed method determining the portioning coefficient of surfactants was developed.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Surfactant Partitioning in Pre-CMC and Post-CMC Regimes for Enhanced Oil Recovery Application

et al. 2019

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The applications of surfactants in Enhanced Oil Recovery (EOR) have received more attention in the past decade due to their ability to enhance microscopic sweep efficiency by reducing oil-water interfacial tension in order to mobilize trapped oil. Surfactants can partition in both water and oil systems depending on their solubility in both phases. The partitioning coefficient (Kp) is a key parameter when it comes to describing the ratio between the concentration of the surfactant in the oil phase and the water phase at equilibrium. In this paper, surfactant partitioning of the nonionic surfactant Alkylpolyglucoside (APG) was investigated in pre-critical micelle concentration (CMC) and post-cmc regimes at 80 °C to 106 °C. The Kp was then obtained by measuring the surfactant concentration after equilibration with oil in pre-cmc and post-cmc regimes, which was done using surface tension measurements and high-performance liquid chromatography (HPLC), respectively. Surface tension (ST) and interfacial tension (IFT) behaviors were investigated by performing pendant and spinning drop tests, respectively—both tests were conducted at high temperatures. From this study, it was found that APG was able to lower IFT as well as ST between water/oil and air/oil, and its effect was found to be more profound at high temperature. The partitioning test results for APG in pre-cmc and post-cmc regimes were found to be dependent on the surfactant concentration and temperature. The partitioning coefficient is directly proportional to IFT, where at high partitioning intensity, IFT was found to be very low and vice versa at low partitioning intensity. The effect of temperature on the partitioning in pre-cmc and post-cmc regimes had the same impact, where at a high temperature, additional partitioned surfactant molecules arise at the water-oil interface as the association of molecules becomes easier.

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The UNIFAC model and the partition of alkyl and alkylphenol ethoxylate surfactants in the excess phases of middle phase microemulsions

Cited by 19 publications

References 41 publications

Robust Flash Calculation Algorithm for Microemulsion Phase Behavior

Robust Flash Calculation Algorithm for Microemulsion Phase Behavior

COSMOplex: self-consistent simulation of self-organizing inhomogeneous systems based on COSMO-RS

Experimental Investigation of Surfactant Partitioning in Pre-CMC and Post-CMC Regimes for Enhanced Oil Recovery Application

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