Carrier Effects on Supported CuCl₂-H₃PO₄-LiCl Catalysts for Oxychiorination of 1, 3-Butadiene

Abstract

The oxychlorination of 1, 3-butadiene over CuCl2-H3P0, -LiCl supported on commercial carriers such as active carbon, silica-gel, r-alumina, celite, silicon carbide and five samples of sintered alumina-silica has been studied. The reaction temperature was 130-275°C and the space velocity was 210 Among the carriers studied, sintered alumina-silica was the best with respect to the selectivity to dichlorobutene and the conversion of butadiene. Other carriers of high surface area were less effective. In the case of sintered alumina-silica, the presence of β-alumina lowered the selectivity and ZrO₂ contained as impurity exhibited a favourable effect.
On the basis of these results, we prepared a catalyst by using as the carrier base a-alumina which contained 0.O^2-5 wt % Zr on the surface and by treating it for 15 hours at 300°C and obtained a maximum conversion of 79% and a 92% selectivity to dichlorobutene. The effect of Zr, however, was restricted to the LiCl promoted catalyst. The increase in the conversion by Zr may be attributed to the increase in the number of effective active because the catalysts with and without Zr gave practically equal activation energies of 30.2 kcal/mol and 31.6 kcal/ mol, respectively, and the difference in the selectivities to dichlorobutene was undetectable.