Enhanced extraction of 2,3‐butanediol by medley solvent of salt and n‐butanol from aqueous solution

Abstract

Enhanced extraction of 2,3-butanediol by adding salt into solvent n-butanol has been studied in this paper. Ternary phase diagrams for 2,3-butanediol + water + salt have been determined. The influences of phase ratio, type of salts and salt content on distribution coefficient and selectivity have also been investigated systematically. With phase ratio of 0.75 (w/w) and salt content of K 2 HPO 4 of 25% (w/w), the distribution coefficient, separation factors and recovery yield in a single extraction process by n-butanol can reach 5.2%, 34% and 80%, respectively. Salt addition can greatly enlarge the two phase region and enhance extraction simultaneously in this system.

Repulsive effect of salt on solvent extraction of 2,3-butanediol from aqueous fermentation solution

“…This study reported K d around 8 for 2,3‐butanediol using ethanol as solvent. Another study reported K d and α value of 5.2 and 34, respectively, with 80% extraction yield using 1‐butanol as solvent and potassium phosphate as salt . To achieve this high recovery yield larger amounts (>25%) of salts were used, making the process uneconomical and less attractive from an industrial‐scale perspective .…”

“…Another study reported K d and α value of 5.2 and 34, respectively, with 80% extraction yield using 1‐butanol as solvent and potassium phosphate as salt . To achieve this high recovery yield larger amounts (>25%) of salts were used, making the process uneconomical and less attractive from an industrial‐scale perspective . Aqueous two phase extraction studies on 2,3‐butanediol extraction reported K d 9.9 and 7.1 for 2,3‐butanediol using isopropanol/ammonium sulfate and ethanol/ammonium sulfate systems .…”

“…29 To achieve this high recovery yield larger amounts (>25%) of salts were used, making the process uneconomical and less attractive from an industrial-scale perspective. 29 Aqueous two phase extraction studies on 2,3-butanediol extraction reported K d 9.9 and 7.1 for 2,3-butanediol using isopropanol/ammonium sulfate and ethanol/ammonium sulfate systems. 26,27 In both these studies, saturated amounts (>15%) of salt were used to achieve such high K d and extraction efficiencies.…”

“…It is postulated that the addition of inorganic salts to dilute aqueous solutions may provide a repulsive effect and help achieve higher extraction efficiencies for various solutes including diols (2,3‐butanediol) . The use of kosmotropic salts can reduce the mutual solubility between the organic and aqueous phase making the process much more likely to recover the solvent completely .…”

Extraction of 2,3-Butanediol with Aqueous Two-Phase Systems Formed by Water-Miscible Organic Solvents and Inorganic Salts

“…In these papers, ethanol and isopropanol as water-miscible alcohols, and dipotassium hydrogen phosphate and ammonium sulfate as inorganic salts were used. Wu et al [21] employed the dipotassium hydrogen phosphate/1-butanol system for the extraction of 2,3-BD, although 1-butanol is not fully water-miscible.…”