Alkylation of benzene for ethylbenzene under supercritical conditions

摘要

The regeneration of the deactivated catalyst produced in the alkylation of benzene with ethylene to ethylbenzene (usually carried out in gas phase or in liquid phase) has received increasing attention. This reaction is accompanied by the formation ofheavy by-products deposited on the catalyst surface and leads to catalyst deactivation, in which the dehydrogenation occurs and provokes coke formation. In the supercritical fluid phase (SCFP) reaction (above the critical point of the reaction mixture),the molecular diffusivity of some coke precursors could be two orders of magnitude (10~2) higher than that in the liquid phase (LP)i, and the solubility could be three orders of magnitude (10~3) higher than that in the gas phase (GP). Therefore, supercritical fluid reactants could be convenient for removing some deposited precursors from the catalyst surface and for prolonging reactor runtime.