(Liquid + liquid) equilibria measurements for ternary systems (sulfolane + a carboxylic acid + n -heptane) at T = 303.15 K and at 0.1 MPa

• Published in: The Journal of chemical thermodynamics 2016-05, Vol.96, p.169-174
• Main Authors: Cele, N.P., Bahadur, I., Redhi, G.G., Ebenso, E.E.
• Format: Article
• Language: English
• Subjects: Acetic acid; Carboxylic acids; Chains; Hydrocarbons; Liquids; Propanoic acid; Solubility; Ternary systems
• ISSN: 0021-9614
• DOI: 10.1016/j.jct.2015.12.019

In the present work, new (liquid + liquid) equilibrium (LLE) values are reported for ternary systems {sulfolane(1) + acetic acid, or propanoic acid, or butanoic acid, or 2-methylpropanoic acid, or pentanoic acid, or 3-methylbutanoic acid (2) + n-heptane (3)} at T = 303.15 K and at p = 0.1 MPa. The mutual solubility of carboxylic acid in sulfolane is dependent on the length and structure of the alkyl chain of the carboxylic acid; it progressively increases with an increase in the alkyl chain of the carboxylic acid. The single phase homogenous region increases as the alkyl chain of the carboxylic acid increases. The n-heptane is most soluble in the carboxylic acid mixtures with long alkyl chain, that is, (3-methylbutanoic acid + sulfolane) and (pentanoic acid + sulfolane) systems and least soluble in the carboxylic acid with short alkyl chain (acetic acid + sulfolane) system. Carboxylic acid together with many other oxygenates and hydrocarbons are produced by SASOL Company in South Africa using the Fischer-Tropsch process. The details about this process are given in introduction section. The NRTL and UNIQUAC models were used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. It was found that the NRTL model fits the experimental values significantly better than the UNIQUAC model.