ALKYLATION OF ISOBUTANE BY ETHYLENE CATALYZED BY CHLORIDED ALUMINA - INFLUENCE OF EXPERIMENTAL CONDITIONS

Chlorided alumina obtained by reaction of alumina with tetrachlorometh ane was tested as a catalyst for alkylation of isobutane with ethylene at 273-373 K. The alkylate composition and the catalyst deactivation were examined under various experimental conditions. At high isobutane /ethylene ratios the catalyst was deactivated rather slowly. A high di lution of ethylene also favoured the production of hexanes versus octa nes, isopentane and heavier products, however the primary products of alkylation were largely isomerized. Whatever the dilution of ethylene, the catalyst stability was improved when the reaction temperature was lowered to 273 K. Then the isomerization of the primary products was less pronounced. Increasing the catalyst mass led to better stability, hexane production was enhanced at the expense of heavier products. Al umina catalysts treated with various chlorinating agents (hexachloroet hane, thionyl chloride, hexachloropropanone, hydrogen chloride) were a lso examined: no marked improvement in either stability or selectivity was noted. Added metal cations did not appear beneficial either.