Isobutane Alkylation with Butene on SO_4~(2-)/ZrO_2 Superacid Catalysts

The activity and selectivity of SO 2- 4/ZrO 2 solid superacid catalysts for the alkylation of isobutane with butene were extensively investigated in a continuous fixed-bed microreactor.The crystal structure,thermal stability and acidity of the catalysts were characterized by means of XRD,DTA and NH 3-TPD methods.The results indicated that strength of acid sites on SO 2- 4/ZrO 2 catalysts was closely correlated with calcination temperature.The medium strong acid sites were the main active sites of alkylation reaction.The higher the acid strength of the catalyst is,the higher the relative activity,and the lower the selectivity of the target products.In general,weak and strong acid sites of the catalysts favor oligomerization and catalytic cracking,respectively. Hydrogen fransfer and isomerization take place easily on medium strong acid sites.The optimum range of acid strength of SO 2- 4/ZrO 2 catalysts for alkylation of isobutane with butenes is -12.7～-8.1.