Dehydration of fructose to 5-hydroxymethylfurfural was performed in a
batch mode in the presence of a series of dealuminated H-form mordenit
es as catalysts, at 165 degrees C, and in a solvent mixture consisting
of water and methyl isobutyl ketone (1:5 by volume). Under the operat
ing conditions used, the reaction was not controlled by external or in
ternal diffusional limitations. Fructose conversion and selectivity to
5-hydroxymethylfurfural were found to depend on acidic and structural
properties of the catalysts used as well as on the micropore vs. meso
pore volume distribution of those catalysts. A maximum in the rate of
conversion of fructose was observed for the H-mordenite with a Si/Al r
atio of 11. A maximum in the selectivity to 5-hydroxymethylfurfural wa
s observed only for H-mordenites with a low mesoporous volume. The hig
h selectivity obtained (> 90%) was correlated with the shape selectivi
ty properties of H-mordenites (bidimensional structure), and particula
rly with the absence of cavities within the structure allowing further
formation of secondary products. The influence of the microporosity v
s, mesoporosity on the selectivity to 5-hydroxymethylfurfural was also
studied, the formation of mesopores upon dealumination procedures bei
ng damaging to obtain a high selectivity. A significant increase in th
e selectivity (10%) was also obtained by simultaneous extraction of 5-
hydroxymethylfurfural with methyl isobutyl ketone circulating in a cou
ntercurrent manner in a continuous catalytic heterogeneous pulsed colu
mn reactor.