Mesoporous titanium dioxide nanocatalyst: a recyclable approach for one-pot synthesis of 5-hydroxymethylfurfural

The present study deals with the production of 5-hydroxymethyl furfural (HMF) from fructose by chemo-conversion method using chemical catalyst, conventionally achieved by microwave-assisted dehydration process. Five different chemical catalysts, namely oxalic acid, phosphotungstic acid and mesoporous titanium dioxide nanoparticles (TNPs) were compared at constant conditions of which TNPs yielded a maxima of 33.95%. The optimum temperature and catalyst loading were found to be 200 degrees C and 20%, respectively, at a 5% optimum substrate concentration during 15min optimum reaction time to yield 61.53% HMF. The efficiency of synthesised TNPs was investigated further through reusability studies. TNPs were properly recycled and the catalytic activity recovery was good even after a 14 batch reactions. The specific surface area of the TNP obtained is about 105.46m(2)/g and its pore-volume is about 0.42cm(3)/g according to single point adsorption. A large accessible surface area combined with a minimal pore size (15.92nm) obtained with mesoporous TNPs is desirable for better catalyst loading, high-yield HMF, retention and reduced diffusion constraints.