Preliminary Research For Effect Of La₂O₃ Content On MPV Reaction Of Cinnamaldehyde To Cinnamyl Alcohol Over La₂O₃/γ-Al₂O₃ Catalyst

Cinnamaldehyde, the major component of cinnamon oil from Chinese cinnamon, produces greatly in GuangXi Province. Cinnamyl Alcohol, selectively reduce product of Gnnamaldehyde, is importance in fine chemicals manufacture. In many approaches of reduction ofα,β-unsaturated aldehydes to unsaturated alcohols, heterogeneous MPV reduction is one of them. Compared with other reaction approaches, heterogeneous MPV reduction shows advantage of high selectivity for C=O, continuous catalytic process and simple treatment after reaction.In order to sift metal oxide active component of supported heterogeneous catalyst for MPV reaction, a MPV reaction on cinnamaldehyde to cinnamyl alcohol was selected as model reaction. Experiment research has found some oxides, such as CuO,ZnO,NiO,CoO_x,ZrO₂ and La₂O₃, showed catalytic activities for model reaction when they were loaded onγ-Al₂O₃. La₂O₃ showed best in them.Reaction time shows largely influenced on convertion of cinnamaldehyde and forming selectivity of cinnamyl alcohol for La₂O₃/γ-Al₂O₃ catalyst. At beginning of the reaction, the convertion of cinnamaldehyde and forming selectivity of cinnamyl alcohol increase with reaction time. When reaction time is longer than 60min., The conversion of cinnamaldehyde increases slowly and forming selectivity of cinnamyl alcohol declines.When the reaction time is 1h, the order of single solvent in favor of reaction is: toluene> isopropanol > ethyl acetate>petroleum etherThe catalysis property of La₂O₃/γ-Al₂O₃ catalyst correlate with the loading amount of La₂O₃. When La₂O₃ content reaches to 9.56%, the convertion of cinnamaldehyde and the forming selectivity of cinnamyl alcohol is 56% and 66% respectively. Preliminary characterization for acid-basic property of La₂O₃/γ-Al₂O₃ samples, we also found surface base amount increase and distrubition of basic sites change with LaO₃ content onγ-Al₂O₃.