The effect of coke deposition on the deactivation of sulfated zirconia catalysts

The formation of coke on sulfated zirconia during the isomerization of n-bu tane was quantified as a function of time on stream and temperature. The fo rmation of coke was essentially linear with time on stream when the isomeri zation reaction was performed at 200 degrees C. When the amount of coke dep osited reached 0.04 wt.%, the catalytic isomerization activity was observed to decrease to 10% of its initial value. When the reaction temperature was increased, the higher selectivity to cracked products resulted in an incre ase in coke formation and a higher rate of deactivation. The deactivated su lfated zirconia catalyst could be completely regenerated in air at 450 degr ees C. The TGA/FT-IR technique used offers significant advantages over othe r methods of quantifying coke deposition. (C) 1998 Elsevier Science B.V. Al l rights reserved.