Equilibrium study on the reactive extraction of heterocyclic monocarboxylic acids from the aqueous solution using Alamine 300/diluent composite solvent: Optimization and modeling of the solvent effect

Abstract

Experiments were conducted to optimize the extraction equilibrium of reactive systems (water + heterocyclic carboxylic acid + Alamine 300/diluent) at T = 298.2 K and P = 101.3 kPa. The uptake capacity of the commercial composite solvent Alamine 300/diluent approximates the order: 2-furoic acid >= alpha-oxo-2-furanacetic acid > tetrahydro-2-furoic acid, and n-heptane < 1,2-dichloroethane < 1-heptanol <= 2-heptanone. Four differentiable models featuring the effects of separation ratio R and synergistic enhancement SE factors are stringently tested to identify global optimization ranges by derivative variation method as follows: 0.2 < R < 0.8 and 4 < SE < 7 for 1-heptanol and 2-heptanone, 1.2 < R < 3.5 and 4 < SE < 6.5 for 1,2-dichloroethane, 2 < R < 80 and 4 < SE < 80 for n-heptane, and Alamine 300 concentration 0.12-0.18 mol dm(-3). Consecutively, the optimum mass transfer stages of a countercurrent extraction are calculated by Kremser-Souders-Brown equation. The equilibrium properties are estimated precisely according to linear solvation energy relation with substantial improvement linear solvation energy relation with substantial improvement (LSER-si), solvation probability relation solvation probability relation (SPR) and Chemodel-modified yielding mean relative errors of 7.0%, 0.08% and 20.4%, respectively.