Suppression of amine disproportionation over Cu or Cu-containing supported catalysts is of particular interest since amine disproportionation leads to reduction in the selectivity of desired amine in general amination reaction.
Therefore, it is necessary to improve catalytic behavior of Cu-containing supported catalyst by making a bimetal with Zn or Ag or by treating Na.
The results of disproportionations over support materials indicated that there exists a relationship between disproportionation activity and acidic strength of support material.
$Cu/SiO_2$ supported catalyst which has been known to be effective for the amination reaction was modified by making a bimetal with Ag or Zn and the results of disproportionation over $Cu-Ag/SiO_2$ or $Cu-Zn/SiO_2$ supported bimetal catalyst showed that the catalytic behavior was improved by making a bimetal with Ag or Zn.
Also, Cu-containing supported catalysts were modified by treating Na and the results of disproportionation over these catalysts were promising.
$Cu-Ag/SiO_2$ supported bimetal catalyst which showed enhanced catalytic behavior was observed using XRD and the results indicate that there is no interaction between Cu and Ag in $Cu-Ag/SiO_2$ supported bimetal catalyst. There is another evidence that Cu and Ag represent their characteristic catalytic behavior and the evidence is that there is a linear relationship between disproportionation activity and Ag/Cu molar ratio.