Effect of 3D open-pores on the dehydration of n-butanol to di-n-butyl ether (DNBE) over a supported heteropolyacid catalyst

Abstract The production of di-n-butyl-ether (DNBE), for use as a blending agent in diesel fuel, is very attractive because the reactant (n-butanol) can be readily produced by the fermentation of bio-derivatives. The dehydration of n-butanol is known to show diffusion-limited characteristics on porous catalysts, such as zeolites or mesoporous supported catalysts. In order to overcome this limitation, herein, we synthesized silica spheres (DSS) with three-dimensional (3D) open pores by a hydrothermal reaction for use as a catalyst for the dehydration of n-butanol. In addition, supported heteropolyacid (PW) catalysts were also prepared on various porous silicas, DSS, SBA-15 and microporous silica (mi-S), to investigate the effect of 3D pore structures on the conversion of n-butanol to DNBE against 2D mesoporous and microporous materials by quantitative calculation. PW/DSS showed the best performance among the catalysts at various temperatures (453, 473, and 493 K). The extent of catalytic performance enhancement was quantified by calculating the effectiveness factor ( η ) based on kinetics data. The η values for PW/DSS, PW/SBA, and PW/mi-S were determined to be 0.83, 0.63 and 0.52, respectively.