Experimental study and kinetic modeling of continuous flow conversion of fructose to 5-(chloromethyl)furfural using micro- and millistructured coiled flow inverter

Abstract

5-(chloromethyl)furfural (CMF) can be derived from renewable feedstocks and is considered as potentially biorenewable platform chemical. Experimental investigations and kinetic modeling of the conversion of d-fructose with aqueous HCl to CMF by a reactive extraction was undertaken with a continuous flow setup. Experiments were performed under variation of extraction solvents, reaction temperatures, fructose concentrations, and reactor diameters for various residence times so that time evolution of species concentration allowed for detailed kinetic analysis. Anisole, a solvent ranked as “recommended” by the CHEM21 selection guide was found to be an environmentally more benign alternative to the typically employed chlorinated extraction solvents. A maximum CMF yield of 79 % was obtained at 90 °C within a residence time of 265 s. Kinetic modeling under non-limiting mass transfer conditions showed general consistency of experimental data with the view that the reactions take place solely in the aqueous phase and that CMF is formed consecutively via 5-(hydroxymethyl)furfural (HMF) from fructose. Under these conditions no side-product formation from CMF and HMF was discernible. Activation energies for conversion of fructose to HMF of 94 ± 8 kJ/mol, of HMF to CMF of 85 ± 6 kJ/mol, and for conversion of CMF to HMF of 74 ± 25 kJ/mol were observed. To the best of our knowledge this study provides the first detailed kinetic investigation of biphasic CMF synthesis under variation of several experimental parameters in continuous flow.