Regular Paper
Synthesis of SrO–Al2O3 Solid Base Catalysts from Strontium Hydroxide and Aluminum Alkoxide by a Solid-liquid Interface Reaction
2021 Volume 64 Issue 2 Pages 103-111
Details
2021 Volume 64 Issue 2 Pages 103-111
Highly dispersed SrO in amorphous Al2O3, SrO–Al2O3, was synthesized by solid-liquid interface reaction of Sr(OH)2 · 8H2O in the solid phase with Al(OCH(CH3)2)3 dissolved in 2-propanol. The water of crystallization in Sr(OH)2 · 8H2O was consumed for the hydrolysis of Al(OCH(CH3)2)3. SrO–Al2O3 catalyst synthesized by solid-liquid interface reaction of equimolar amounts of Sr(OH)2 · 8H2O and Al(OCH(CH3)2)3, then heat treated at 673 K, exhibited the highest activity among the prepared catalysts for the base-catalyzed retro-aldol reaction of diacetone alcohol. Catalytic activity of SrO–Al2O3 catalyst calcined at 673 K was twice that of SrO–Al2O3 catalyst prepared by physical mixing of Sr(OH)2 · 8H2O with Al2O3. Active SrO–Al2O3 catalyst was obtained by heating at a temperature just below that of Sr3Al2O6 crystallization. Formation of SrO by heat treatment at 673 K was confirmed using X-ray absorption near edge structure analysis. The SrO particle size was too small for detection by powder X-ray diffraction. We found that interface reaction of a metal hydroxide in the solid phase with an alkoxide in the liquid phase is useful for the preparation of well-dispersed mixed metal oxides under mild conditions.
