Lewis acidity induced heteropoly tungustate catalysts for the synthesis of 5-ethoxymethyl furfural from fructose and 5-hydroxymethylfurfural

Abstract

Heteropoly tungstate with tantalum ions in its secondary structure were prepared and subsequently dispersed on tin oxide. The prepared materials physical and chemical properties were estimated by different spectroscopic methods Characterization results indicate that the stable Keggin ion of tantalum heteropoly tungstate was well preserved on support. New Lewis acidic sites were generated with the presence of Ta ions in heteropoly tungstate. These samples were tested for their catalytic performance towards conversion of fructose to 5-ethoxy methyl furfural (EMF) and selective etherification of 5-hydroxymethylfurfural (HMF) with ethanol. The catalyst with 30 wt% of active component on SnO2 exhibited highest HMF etherification activity with 90% of 5-ethoxymethylfurfural yield with in 45 min. The catalysts also able to converted fructose into EMF in one-pot with a yield of 68%. The etherification activity over these catalysts was studied under the influence of different reaction parameters such as reaction temperature, reaction time, catalyst weight and reactants mole ratio.