Paper Title
Liquid-Liquid Equilibria, Solid-Liquid Equilibria and Mixture Properties for The Separation of Biobutanol Fermentation Products

Liquid-liquid equilibria (LLE) for extraction of butyric acid in aqueous system and in addition, solid-liquid equilibria (SLE), excess volume and deviation of molar refractivity for binary mixtures of acetic acid with C3 to C5 carboxylic acids: propionic, butyric and pentanoic acid, which are mostly biobutanol fermentation broth. LLE and SLE measurement was carried out under atmospheric pressure using self-made grass vessel while excess volume and deviation of molar refractivity were determined from directly measured density and refractive indices using precision densitometer and refractometer. All the determined LLE data for water+ butyric acid + heavy ether compound showed Treybal type II phase behavior, while SLE for binary mixtures of {acetic acid + C3 - C5 carboxylic acid} showed single eutectic point. The LLE and SLE data correlated well with common activity coefficient models within 0.6 K of root mean square standard deviation. The excess molar volumes (V^E) for the acetic acid + C3 - C5 carboxylic acid binary mixtures showed positive values for entire ranges of compositions, while the molar refractivity deviation (∆R) showed negative values. The excess and deviation properties were modeled well by polynomial equations, namely Redlich-Kister within 0.006 cm^3∙mol^(-1)of standard deviation for V^E and 0.02 cm^3∙mol^(-1) for ∆R, respectively. Keywords - Biobutanol, Phase Equilibria, Carboxyric Acid,Excess Volumes, Refractivity Deviation