Efficient conversion of fructose to 5-[(formyloxy)methyl]furfural by reactive extraction and in-situ esterification

5-[(Formyloxy)methyl]furfural (FMF), an analogue of 5-(hydroxymethyl)furfural (HMF) is becoming more attractive due to its superior stability and hydrophobicity, which make it easier to refineand store. In the present study, FMF was produced from fructose by one-pot approach in pure formic acid media or by a two-step approach via HMF in choline chloride (ChCl)/fructose deep eutectic solvents (DES) system. A favorable FMF yield of 63.22% was reached by two-step approach. In addition, the effects of reaction parameters, such as temperature and acidity, on preparation of FMF from fructose were systematically investigated. The dehydration of fructose into HMF was confirmed as the rate-controlling step in the consecutive reaction. Ultimately, the separation and purification procedures of FMF were put forward. The FMF with a purity of 98.8% was obtained finally. Meanwhile, the FMF purified by saturated sodium bicarbonate solution showed an excelled storage stability.