5-hydroxymethylfurfural (5-HMF) is a compound that is becoming increasingly recognized due to its utility in the field of biofuels and chemical production. A key method for its production is the liquid-liquid extraction, during which the 5-hydroxymethylfurfural is extracted from aqueous to organic phase. A thorough understanding of the tricomponent system water–5-hydroxymethylfurfural–organic solvent equilibrium is needed for a successful establishment of the aforementioned process.
The purpose of this work is choosing a solvent for extraction of 5-HMF with a good yield. An extraction isotherm, in a selected concentration range, was determined for solvents 2-ethylhexan-1-ol (2-EtH), cyclopentyl methyl ether (CPME), isophorone (ISP), benzyl alcohol (BnOH), 2-sec-butylphenol (2-SBP) and tetrahydrofuran (THF). We prepared a series of biphasic systems of different volumetric ratios (O/Aq)vol, with the aqueous phase containing 1,5, 5 or 9 wt% of 5-HMF. We also conducted a screening test for two series of randomly selected solvents with different polarities in a 1:1 volumetric ratio.
The amount of 5-HMF in each phase was determined with HPLC analysis by calibration standards. From the results we calculated the partition coefficient (Kd) and quantified the solvent's extraction capabilities.
THF with addition of NaCl showed the best results, partition coefficient of this system was 9,1. ISP and BnOH reached partition coefficients of 3,65 and 3,8, meanwhile the Kd for 2-SBP fell into the 1,8–9 range. Kd for solvents methyl isobutyl ketone (MIBK), ethylacetat (EtAc), butan-2-ol (2-BuOH), 2-methyl-2-butanol (TAA) and 2 methyltetrahydrofuran (2-MTHF) moved within the 1-2 range.
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