Glucose dehydration reaction over metal halides supported on activated charcoal catalysts.

Different metal halide catalysts supported on a commercial active charcoal have been synthesized, activated, characterized and tested in glucose dehydration to 5-hydroxymethylfurfural using a biphasic water/methyl isobutyl ketone media. The influence of the cation nature (K+, Ca2+, Sr2+, Mg2+) and anion nature (F-, Cl-, Br-) on the catalytic performance of the solid is discussed in terms of glucose conversion, HMF yield and products selectivity. The activation of the impregnated catalysts results in a great diversity of active sites, such as Bronsted sites (carboxylic groups), basic sites (metal oxide), and Lewis acid site (Mn+). Their distribution within the samples determinates the resulting products and the final HMF yield. [Display omitted] • Metal Halide catalysts supported on active carbon are active in the glucose dehydration to 5-HMF. • Cation (K+, Ca2+, Sr2+, Mg2+) and anion nature (F-, Cl-, Br-) affects the catalytic performance. • Thermal activation of the catalysts decreases the surface acidity and originates new active sites, such as MOx. • Activated catalysts shows higher glucose conversions and minor HMF selectivity than fresh ones. • The best performing catalyst is stable and maintains it activity during four cycles of reutilization. [ABSTRACT FROM AUTHOR]