| The La2O3/γ-Al2O3catalysts showed a fine catalytic effect in reaction system when isopropanol used as hydrogen transfer reagent and toluene used as solvent. These La2O3/γ-Al2O3catalysts also catalyzed the adole condensation reaction of cinnamaldehyde with acetone at the same time in catalytic reaction. The main product of reaction was determined as6-phenyl-3,5-diene-2-hexanone. In accordance with the initial research, the influence of acid/base sites character of the catalysts on the reaction was investigated by using NH3and CO2as probe molecules to block for acid/base sites on the catalysts. New species was adhibitted on La2O3/γ-Al2O3catalysts to change acid/base sites on La2O3/γ-Al2O3catalysts, and then react the MPV reactions. Some conclusions are drawn as followings:1. La2O3/γ-Al2O3samples showed better catalytic activity than y-Al2O3samples. The activity of La2O3/γ-Al2O3samples declined by using NH3and CO2as probe molecules to block for acid/base sites on the catalysts. The experiment result showed that acid and base sites also gave influence on MPV reaction of cinnamaldehyde. The influence of acid sites was larger than that of base sites on the reaction. 2. When the blocked acid sites on the catalysts is set free, the selectivity of cinnamyl alcohol is increased, but the selectivity of the main product A is decreased.3. When NiO is loaded on La2O3/γ-Al2O3samples, the surface acid/base sites and the surface areas are changed, which showed largely influence on reactivity of MPV.4. After a lot of reactions, when NiO content reaches to4.18wt.%, La2O3content reaches to9.45wt.%, the catalysts showed the best effect, the convertion of cinnamldehyde is83.38%.5. The activity of La2O3/γ-Al2O3samples and NiO-La2O3/γ-Al2O3samples declined with increasing of reaction times (or total reaction time) gradually, the main cause of catalysts deactivation was strong adsorption of organics on catalytics surface. |
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