Calcium alginate-TiO2/SiO2 nanocomposite for glucose conversion to 5-hydroxymethylfurfural

Abstract

The sodium alginate biopolymer used to form calcium alginate-TiO2/SiO2 nanocomposite has been successfully synthesized. The first stage is synthesis of TiO2/SiO2 composites by the sol-gel method using tetraethyl orthosilicate (TEOS) and titanium isopropoxide (TTIP) precursors. Calcium alginate nanocomposite is formed from the crosslinking process between Ca2+ ions from CaCl2.2H2O with sodium alginate combined with TiO2/SiO2 composites, characterized by Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Tunneling Electron Microscopy (TEM). The average particle size of TiO2/SiO2 composite on the surface of calcium alginate obtained by TEM is about 50 nm. The application of calcium alginate-TiO2/SiO2 nanocomposite as catalyst is used for conversion of glucose into 5-hydroxymethylfurfural (HMF) using dimethyl sulfoxide (DMSO) solvents. The best glucose conversion obtained at 140 °C for 4 hours is 97 % and optimum HMF yield obtained at 140 °C and 5 hours is 40 %. Nanocomposites based on sodium alginate biopolymers combined with TiO2/SiO2 composites can be developed as new superior materials and promising catalysts because it is easily obtained and biodegradable.