화학공학소재연구정보센터
Chemical Engineering Research & Design, Vol.93, 531-540, 2015
Comparison of solvents for the recovery of low-molecular carboxylic acids and furfural from aqueous solutions
Liquid-liquid extraction of formic acid, acetic acid and furfural from an aqueous synthetic acid hydrolysis process stream is studied. Different types of extractants are first evaluated and two solvents that can efficiently recover the compounds, 2-methyltetrahydrofuran (2-MTHF) and tri-n-octylamine in toluene (Alamine 336-toluene) are then studied further. Important considerations in solvent selection were the efficiency of solvent regeneration and the recovery of the extractives from the loaded solvents. Solvent regeneration experiments were carried out under a vacuum in a spinning band distillation unit. Both solvents showed good regeneration characteristics. The rate of phase separation for Alamine 336 increased, without the formation of an emulsion, when performing extractions at low mixing rates. The use of toluene as a diluent for Alamine 336 prevented the formation of a third intermediate phase. In general, the equilibrium favors the extraction of formic acid for Alamine 336 and the extraction of furfural for 2-MTHF. For acetic acid there was only a small difference in the distribution coefficients for both solvents. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.