t-Butyl alcohol (TBA) is an important octane enhancer that is used to replace lead additives in gasoline [Ind. Eng. Chem. Res., 27, 2224 (1988)]. TBA was produced by the liquid-phase hydration (W) of isobutene (I) over an Amberlyst-15 catalyst. The system is normally a multiphase mixture of hydrocar- bon, water, and solid catalysts. However, the use of cosolvents or excess TBA can achieve reasonable miscibility. The reaction mechanism is believed to be I+S I:S . W+S WS (P10-3.1) (P10-3.2) (P10-3.3) (P10-3.4) W.S+I:S TBA S+S TBA :S TBA + S Derive a rate law assuming: (a) The surface reaction is rate-limiting. (b) The adsorption of isobutene is limiting. (c) The reaction follows Eley-Rideal kinetics I.S + W TBA :S . (P10-3.5) and the surface reaction is limiting. (d) Isobutene (I) and water (W) are adsorbed on different sites. I Si (P10-3.6) I + Si W + S2 = W S2 TBA is not on the surface, and the surface reaction is rate-limiting. (P10-3.7)