t-Butyl alcohol (TBA) is an important octane enhancer that is used to replace lead additives in gasoline. t-Butyl alcohol was produced by the liquid-phase hydration (W) of isobutene (I) over an Amberlyst-15 catalyst. The system is normally a multiphase mixture of hydrocarbon, water and solid catalysts. However, the use of cosolvents or excess TBA can achieve reasonable miscibility. The reaction mechanism is believed to be