The nanostructured mesoporous Pd/MCM-41 catalyst was prepared by impregnation.This catalyst exhibited high activity and selectivity to piphenyl during Ullmann coupling reaction of iodobenzene.With Pd loading of 12%,the biphenyl yield may reach 50%,showing its good potential to match the homogeneous catalyst in traditional Ullmann coupling reactions.Based on BET and XRD etc.characterizations,the relationship between the excellent catalytic properties of the Pd/MCM-41 and its structural characteristics was discussed briefly.
Sustained oscillations were observed in the BrO3?-fructose-Mn2+-H2SO4 system. Unlike the classical BZ oscillations, the present oscillations might be considered as radical- controlled rather than bromide-controlled since no substance subjected to bromination was present. Addition of acetone induced dual-frequency oscillations comprised of both the radical-controlled and the bromide-controlled oscillations.
