Investigation of levulinic acid distribution from aqueous phase to organic phase with TOA extractant

Abstract

Levulinic acid, which is a carboxylic acid with a ketone structure, is a clear to brownish semisolid; it melts at 37 C and is soluble in alcohol, ether, and chloroform. Levulinic acid can be used as an acidulant in foods and beverages. The extraction of levulinic acid with trioctylamine (TOA), dissolved in five alcohol solvents (isoamyl alcohol, hexan-1-ol, octan-1-ol, nonan-1-ol, and decan-1-ol) and two ketones (diisobutylketone (DIBK) and methylisobutylketone (MIBK)) were investigated. In addition to these amine systems, experiments were also conducted with single solvents. All measurements were performed at 298.15 K. Organic solutions of amines are being used increasingly to separate organic acids from aqueous mixture solutions via reactive extraction. The extent to which the organic phase may be loaded with levulinic acid is explained by calculating the loading ratio (T), extraction efficiency (E), and distribution coefficients (K-D). Isoamyl alcohol was determined to be the most effective solvent, with a maximum distribution value of 11.303. Possible equilibrium complexation constants for acid: amine ratios of 1: 1 and 2: 1 have been determined, with maximum values of 6.530 and 116.608 for K-11 and K-21, respectively, with isoamyl alcohol. Furthermore, a linear solvation energy relationship (LSER) model equation has been obtained to calculate the distribution coefficients for alcohols, with a correlation coefficient of R-2 = 0.97.