Glycolaldehyde co-extraction during the reactive extraction of acetic acid with tri-n-octylamine/2-ethyl-1-hexanol from a wood-based pyrolysis oil-derived aqueous phase

Glycolaldehyde and acetic acid are promising bio-based platform chemicals, which could be extracted from a wood-based pyrolysis oil-derived aqueous phase. The aim of this paper was to study the effect of the aqueous feed composition and tri-n-octylamine/2-ethyl-1-hexanol concentration on the acetic acid extraction and glycolaldehyde co-extraction performance. In the physical and reactive extractions, glycolaldehyde and acetic acid are extracted independently from each other. In the physical extraction, the feed composition has a slight influence on the distribution coefficients and yields of both acetic acid extraction and glycolaldehyde co-extraction. In the reactive extraction, the acetic acid extraction and glycolaldehyde co-extraction are relatively independent of the feed composition. For a combined one-step acetic acid and glycolaldehyde extraction pure 2-ethyl-1-hexanol solvent provides the highest yields. Although 40 wt.% tri-n-octylamine provides the best acetic acid extraction performance, a solvent containing more than 50 wt.% tri-n-octylamine in 2-ethyl-1-hexanol is preferred for a two-step scenario in which acetic acid is extracted prior to glycolaldehyde, due to the decrease of glycolaldehyde co-extraction with increasing tri-n-octylamine concentration.

► We extract acetic acid and glycolaldehyde from pyrolysis oil-derived aqueous phase.
► Feed composition has a minor influence on the physical extraction.
► The performance of reactive extraction is independent of feed composition.
► Extraction with 2-ethyl-1-hexanol is needed for a combined one-step recovery.
► Extraction at a concentration above 50 wt.% TOA is needed for a two-step separation.