The alkylation of Raffinate II and isobutane in the liquid phase over novel Nafion resin/silica nanocomposites with 13-16% of Nafion entrapped within a porous silica network (SAC 13) produces isooctane in high yields. Using a step-up design under batch conditions at 353 K, high conversions of isobutane and Raffinate II were observed. The catalyst was active up to 90 min before deactivating due to alkene oligomerization. Strong evidence of hydride transfer based on different trimethylpentane selectivity was observed. The nanocomposites are directly recyclable with only low catalyst deactivation.