Selective glucose dehydration over novel metal phthalocyanine catalysts at low temperatures

Abstract

In this report, promising carbon-based novel metal phthalocyanine catalysts were prepared and tested in glucose dehydration at low temperatures (90-130 degrees C) under atmospheric conditions. Most of the prepared phthalocyanines exhibited high conversions in dimethylsulfoxide (DMSO). A complete conversion of glucose was obtained over Aluminum phthalocyanine (AlPcCl) and Tin phthalocyanine (SnPcCl2) catalysts. AlPcCl also provided the highest HMF yield (53% in 3 h at 130 degrees C). Al3+ cations promoted the glucose conversion and Cl- anions played an active role in 5-Hydroxymethylfurfural (5-HMF) formation. Dimethylsulfoxide (DMSO) as a solvent, was also found effective with phthalocyanines for high 5-HMF yield by stabilizing its structure. Thus, the 5-HMF yield was observed high (53.0% at 130 degrees C for 3 h) over AlPcCl in DMSO. Kinetic studies showed that the optimum reaction temperature was 130 degrees C at 1/5 catalyst/glucose ratio for 3 h. Dehydration reactions, performed in the aqueous phase, exhibited higher fructose selectivities with AlPcCl catalyst.