Modification of the Interlayer in Lanthanum-Niobium Oxide and Its Catalytic Reactions

ISSN： 0021-9517

Source： Journal of Catalysis, Vol.168, Iss.1, 1997-01, pp. : 26-34

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Abstract

The methods for preparation of pillared materials with ZrO 2 , TiO 2 , or SiO 2 in the interlayer of layered perovskite structural oxides, HLaNb 2 O 7 (HLa), were examined in detail. HLa that had been intercalated with n -amines of different carbon chain lengths was used in pillaring ZrO 2 . N -octyl- and decylamine were useful in the construction of the pillar. It is of critical importance to enlarge the interlayer spacing of the HLa by using filling with n -octylamine for the intercalation of the precursor of ZrO 2 , TiO 2 , or SiO 2 . The precursor of ZrO 2 or TiO 2 could easily be intercalated by exchange with n -octylamine. When pillaring with SiO 2 was done, the preparation was not as easy as pillaring with ZrO 2 or TiO 2 . The molar ratio of tetraethoxysilane (TEOS), the concentration of HCl, and the amount of ethanol was closely related in the preparation. The optimum preparation condition was a molar ratio of TEOS:ethanol:HCl (2 or 3 M ) of 10:5:0.5 to 1 mol of HLaNb 2 O 7 fully filled with n -octylamine at 40#°C. Thus, the materials prepared (by pillaring with ZrO 2 , TiO 2 , or SiO 2 ) were used as a catalyst in the dehydration of 1-butanol. Enhancement of activity was detected on all the pillared catalysts. It was caused by interaction between the pillaring material and the host matrix. The TiO 2 pillared catalyst exhibited the highest activity in hydration, followed by the ZrO 2 and SiO 2 pillared catalysts. All of the catalysts that were examined consisted of a large amount of mesopore, in which the TiO 2 pillared catalyst exhibited the presence of a larger ratio of mesopore, as compared with other catalysts.