Oxidative Dehydrogenation of Ethylbenzene to Styrene on an Exhausted Aluminum Chromium Catalyst

Abstract

The catalysts were synthesized based on the spent industrial aluminum-chromium catalyst used in the hydrocarbon dehydrogenation by SABIC Co., and the catalysts were modified with copper and potassium carbonate. The catalysts were tested in the oxidative dehydrogenation of ethylbenzene to styrene. It was found that the prepared and modified 1 wt % Cu catalyst, upon the conversion of ethylbenzene to styrene in the presence of O2, exhibits an activity of 53% with a selectivity for styrene of 85%. It was shown that the introduction of carbon dioxide into the reaction zone leads to an increase in activity to 60–63%, and selectivity to 89–91%. The stability of the functioning of a copper-promoted catalyst and the effect of water vapor on the process were studied. It was found that under conditions close to industrial, within 100 h, a stable conversion of the mixture (ethylbenzene : O2 = 9 : 1) : H2O = 4 : 1 with a selectivity for styrene of at least 90% at a space velocity of 2 h–1 (at liquid ethylbenzene).