A ZnAl2O4@SiO2 nanocomposite was prepared from metal nitrates and tetraethyl orthosilicate by the sol-gel process,and characterized by X-ray diffraction,Fourier transform infrared,transmission electron microscopy,and ...A ZnAl2O4@SiO2 nanocomposite was prepared from metal nitrates and tetraethyl orthosilicate by the sol-gel process,and characterized by X-ray diffraction,Fourier transform infrared,transmission electron microscopy,and N2 adsorption-desorption measurements.The nanocomposite was tested as a heterogeneous catalyst for the acetylation of alcohols,phenols,and amines under solvent-free conditions.Under optimized conditions,efficient acetylation of these substrates with acetic anhydride over the ZnAl2O4@SiO2 nanocomposite was obtained.Acetylation of anilines and primary aliphatic amines proceeded rapidly at room temperature,while the reaction time was longer for the acetylation of alcohols and phenols,showing that an amine NH2 group can be selectively acetylated in the presence of alcoholic or phenolic OH groups.The catalyst can be reused without obvious loss of catalytic activity.The catalytic activity of the ZnAl2O4@SiO2 nanocomposite was higher than that of pure ZnAl2O4.The method gives high yields,and is clean,cost effective,compatible with substrates having other functional groups and it is suitable for practical organic synthesis.展开更多
基金supported by the Lorestan University Research Council and Iran nanotechnology Initiative Council
文摘A ZnAl2O4@SiO2 nanocomposite was prepared from metal nitrates and tetraethyl orthosilicate by the sol-gel process,and characterized by X-ray diffraction,Fourier transform infrared,transmission electron microscopy,and N2 adsorption-desorption measurements.The nanocomposite was tested as a heterogeneous catalyst for the acetylation of alcohols,phenols,and amines under solvent-free conditions.Under optimized conditions,efficient acetylation of these substrates with acetic anhydride over the ZnAl2O4@SiO2 nanocomposite was obtained.Acetylation of anilines and primary aliphatic amines proceeded rapidly at room temperature,while the reaction time was longer for the acetylation of alcohols and phenols,showing that an amine NH2 group can be selectively acetylated in the presence of alcoholic or phenolic OH groups.The catalyst can be reused without obvious loss of catalytic activity.The catalytic activity of the ZnAl2O4@SiO2 nanocomposite was higher than that of pure ZnAl2O4.The method gives high yields,and is clean,cost effective,compatible with substrates having other functional groups and it is suitable for practical organic synthesis.
