Equilibrium & kinetic studies of reactive extraction of trans-aconitic acid using sunflower oil with tri-n-octylamine

Abstract

Abstract In order to design an efficient extraction system for the separation of biochemically produced trans-aconitic acid (TAH) from fermentation broth; equilibrium and kinetics of reactive extraction of TAH from aqueous solutions was investigated using tri-n-octylamine (TOA) as an extractant and sunflower oil as a diluent. Through the equilibrium studies stoichiometry (acid, extractant) of complex formations was determined with the help of loading ratio. Formation of (1, 1), (2, 1), & (3, 1) stoichiometry complexes were observed having complexation constants values 179.73 kmol−1 m3, 9512.58 kmol−2 m6, and 614,407.02 kmol−3 m9, respectively. Kinetics experiments were performed in Lewis type stirred cell and results confirmed that reaction between TAH and TOA in sunflower oil fall in regime 1, i.e. slow reaction occurring in bulk organic phase. The overall order of reaction is pseudo first order with rate constant (K mn ) 1.78 × 10−5 (kmol m−3)−0.71 s−1 and physical mass transfer coefficient (K l ) 4.22 × 10−5 m s−1.