Sn exchanged acidic ion exchange resin for the stable and continuous production of 5-HMF from glucose at low temperature

[Display omitted] •Cheap catalyst for the conversion of sugars to 5-HMF at 120 °C.•Facile preparation via SnCl2 exchange to acidic Amberlyst-15 resin.•Catalysts show high stability in continuous flow 5-HMF production. This report discusses the easy and cheap preparation of SnCl2 exchanged Brønsted acidic Amberlyst-15 ion exchange resin prepared by ion exchange of an aqueous SnCl2 solution at room temperature. The prepared materials were tested in the conversion of sugars, being glucose, fructose and saccharose to 5-HMF at low temperature conditions (120 °C) and high sugar concentrations (30 wt. %). Materials showed activity in the conversion of glucose, fructose and saccharose. The effect of the repeating exchange procedures on the catalytic performance was studied under batch and continuous flow conditions. The physicochemical properties of the Amberlyst materials were characterized by various techniques, among them NH3-TPD, N2 physisorption and XRF experiments. The superior stability over 120 h and the selectivity towards 5-HMF of the SnCl2 exchanged Amberlyst material under continuous flow conditions was partially attributed to a reduced concentration of the total acid site concentration, preventing products to react further towards poorly defined humin-type products.