Use of free air as oxidant and copper(II)chloride as catalyst,3,3'-di-tert-butylbi-phenyl-2,5,2',5'-diquinone(BBDQ)was prepared via catalytic oxidation of 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethoxy-biphenyl(di-BHA).The yield of reaction attained 95% and the selectivity for BBDQ was 100%.The single-crystal X-ray diffraction analysis reveals that the dihedral angle between two rings(benzene rings for di-BHA and quinone rings for BBDQ)changes from 89.8 to 45.3o,indicating the steric hindrance effects of methyl disappear in the oxidation process.The crystal structures of di-BHA and BBDQ are further confirmed by their spectral characterizations.The probable mechanism for this oxidation process is also discussed.
Nanometer SnO2 particles were synthesized by sol-gel dialytic processes and used as a support to prepare CuO supported catalysts via a deposition-precipitation method. The samples were characterized by means of TG-DTA,XRD,H 2-TPR and XPS. The catalytic activity of the CuO/TiO2-SnO2 catalysts was markedly depended on the loading of CuO,and the optimum CuO loading was 8 wt.%(T 100 = 80 C) . The CuO/TiO2-SnO2 catalysts exhibited much higher catalytic activity than the CuO/TiO 2 and CuO/SnO 2 catalysts. H 2-TPR result indicated that a large amount of CuO formed the active site for CO oxidation in 8 wt.% CuO/TiO2-SnO2 catalyst.
Kairong Li Yaojie Wang Shurong Wang Baolin Zhu Shoumin Zhang Weiping Huang Shihua Wu
