The Effects of Additives on the Activities of Supported Copper(II) Chloride Catalysts for Oxychlorination of 1, 3-Butadiene

Abstract

For the oxychlorination of 1, 3-butadiene to obtain, 3, 4-dichloro-1-butene and 1, 4-dichloro2-butene, copper (II) chloride supported on sintered alumina-silica was found to be a suitable catalyst. The conversion of 1, 3-butadiene and the selectivity for dichlorobutenes were found to be improved by the addition of alkali metal chlorides. Phosphoric acid was effective for the improvement of selectivity. The addition of both compounds gave a better result.
The conversion and the selectivity obtained by a catalyst composed of CuCl2, LiCl, H₂PO₄ and carrier, for example, with a weight ratio of 1.86 x 10-2, 1.96 X 10-3, 1.51 x 10-8 and 1.0, were 72% and 92%, respectively, at 2509C and a space velocity of 210 hr'. for the effect of alkali ions, butadiene conversion at 200'C decreased in the following order, Csfrz-, R. b>Na> Li, while the selectivity for dichlorobutenes at 250°C showed different order, Li > Na > Rb> Cs, although the effect of KCI was somewhat different.
The butadiene conversion was independent of reactant gas pressure in the case of alkali promoted catalysts, but dependent on HCl in the case of unpromoted catalysts. Therefore, the addition of alkali metal chloride seemed to speed up the velocity of oxychlorination by activation of HCI.