Creating a Heterohomogeneous Catalytic System for the Alkylation of Benzene with Ethylene through the Reaction beteen Carbon Tetrachloride and Aluminum Alloys

Abstract

The in situ formation of a catalytic heterohomogeneous system containing Al–M alloy (M is Ni, Co, Cu) and Al(M)/Cl complex in a benzene–ethylene medium at a temperature of 80°C and a pressure of 0.2–0.3 MPa is studied. The characteristic patterns of interaction between Al–M alloys activated with a liquid metal Ga–In eutectic and a chlorinating agent (CCl₄) with the formation of catalytically active metal–aluminum chloride Al(M)/Cl complexes are established. Results from spectrokinetic measurements show the order of the reactivity of activated alloys with respect to excess CCl₄ is Al–Cu ≈ Al–Ni > Al > Al–Co. The highest catalytic activity is displayed by nickel–aluminum chloride complexes whose selectivity toward ethylbenzene is 48%. Data from IR and UV-VIS spectroscopy show that the structure and composition of metal chloride complexes formed in situ in the aromatic reaction medium is determined by a combination of coupled ionic pairs \([{\text{AlC}}{{{\text{l}}}_{4}}]_{{{\text{tetr}}}}^{ - }{\text{/[NiC}}{{{\text{l}}}_{{\text{6}}}}]_{{{\text{oct}}}}^{{4-}}\) and \(\left[ {{\text{AlC}}{{{\text{l}}}_{{\text{4}}}}} \right]_{{{\text{tetr}}}}^{ - }/\left[ {{\text{CuC}}{{{\text{l}}}_{{\text{2}}}}} \right]_{{{\text{lin}}}}^{ - }\), which are stabilized by (C₆H₅)₃C⁺ carbocation.