25 research outputs found

    Experimental and Molecular Modeling Study of the Three-Phase Behavior of ( n

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    Measurements and modelling of the viscosity of six synthetic crude oil mixtures

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    The viscosity and density are reported for six synthetic mixtures, composed of up to 13 components, designed to match a light, dead crude oil of API 32° and molar mass of approximately 184 g mol−1. The measurements were made in the liquid region at temperatures between (323 and 398) K and in the pressure range from 1 MPa to 70 MPa. The viscosity was measured with a vibrating-wire viscometer, while the density was measured by means of a vibrating U-tube densimeter. The density and viscosity data have expanded relative uncertainties of 0.12% and 1.2%, respectively with a coverage factor of 2. We have used the measured viscosity data to test the predictive power of the four viscosity models, the extended hard sphere (EHS), one-component EHS (1-cEHS), three-component EHS (3-cEHS) and Vesovic-Wakeham (VW), that have their basis in kinetic theory and the molecular description of the fluid. Two of the models (EHS and VW) require full compositional description of the mixture, while the other two belong to a new family of models which dispense with full compositional characterization, but retain molecular description. On average the EHS and VW models predict the viscosity data with lower deviations than 1-cEHS and 3-cEHS models, but all four models represent the data with uncertainty of 5–10%

    Lipidic Protic Ionic Liquid Crystals

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    Protic ionic liquids (PILs) based on lipidic compounds have a range of industrial applications, revealing the potential of oil chemistry as a sustainable basis for the synthesis of ionic liquids. PILs of fatty acids with ethanolamines are here disclosed to form ionic liquid crystals, and their mixtures with the parent fatty acids and ethanolamines display a lyotropic behavior. Aiming at characterizing their rheologic and phase behavior, four ethanolamine carboxylates and the mixtures used for their synthesis through a Bronsted acid base reaction are investigated. Their phase diagrams present a complex multiphase profile, exhibiting lyotropic mesophases as well as solid liquid biphasic domains with a congruent melting behavior. These PILs present a high self-assembling ability and a non-Newtonian behavior with yield stress in the liquid crystal mesophase. The appearance of lamellar and hexagonal structures, with probably normal and inverted configurations in the mixtures, due to the formation of the PILs is responsible for the high viscoelasticity and notable nonideality that is mainly ruled by hydrophobic/hydrophilic interactions. Considering their renewable origin, the formation of liquid crystalline structures, in addition to the non-Newtonian behavior and ionic liquids properties, and the mixtures here great potential, and numerous applications may be foreseen
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