Modeling and Optimization of Reactive Extraction of Citric Acid

Abstract

Reactive extraction of citric acid from dilute aqueous solutions was studied using three different extractants, namely tri-n-butylphosphate (TBP), tri-n-octylamine (TOA), and Aliquat 336 (A336), dissolved in three different diluents: butyl acetate, decanol, and benzene. The isothermal batch equilibrium experiments were carried out at T = 300.15 ± 1 K. The extraction was interpreted in terms of the distribution coefficient (K D ). Maximum extraction efficiency (E = 95.5%) was obtained at 20% (v/v) TOA in butyl acetate with complexation constant K E2 = 1039.7 (kg mol −1 ) 2 for the (2:1) complex. In addition to having a higher loading ratio (Z > 0.5), the overloading of amine(TOA) in the case of the citric acid + TOA + decanol system was also confirmed by spectroscopic (FTIR) analysis. The linear solvation energy relationship model was successfully applied to predict the distribution coefficient. The complex stoichiometry was also optimized using differential evolution. A close resemblance was observed between experimental and model values.

Reactive Extraction of Lactic Acid, Formic Acid and Acetic Acid from Aqueous Solutions with Tri-n-octylamine/1-Octanol/n-Undecane

“…Usually, the solvent phase in reactive extraction consists of three components, the reactive extractant, the modifier and the diluent. The purpose of the reactive extractant is the reaction with the targeted substances, the diluent decreases the density and the viscosity, while the modifier increases the solubility of the complex or salt formed in the solvent phase [22,29,30]. The influence of the diluent n-undecane and the modifier 1-octanol in the solvent phase on the extraction efficiency of lactic acid was investigated further.…”

Self-optimising reactive extractions: towards the efficient development of multi-step continuous flow processes

“…However, only the reaction conditions were varied in each optimisation, despite the potential impact variables such as pH and solvent ratios have on the efficiency and volume productivity of downstream work-ups. Typically, reactive LLEs have been optimised using either statistical [17] or physicochemical based modelling, [18,19] which require relatively small amounts of material. However, modelling approaches suffer from an increased complexity with an increasing number of species and/or protic sites in solution, which can result in low accuracy predictions [18].…”

Solvent Extraction of Citric Acid with Different Organic Phases

“…Thakre et al [19] carried out experiments using the same concentration of citric acid (0.5 mol•kg −1 , that is equivalent to10% w/v), but using 30% TBP in different diluents. For each of the diluents used, different extraction percentages were obtained: 5%, 10%, and 14% for benzene, decanol, and n-butyl acetate, respectively.…”

“…[21]. TBP was also used for citric acid extraction by Thakre et al [19]. The use of alcohols is common due to their amphiphilic characteristics: their polar part interacts with the polar portion of the complex and the non-polar part interacts with the diluent, favoring the solvation of the complex in the organic phase.…”