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 hydrocarbon, water, and solid catalysts. However, the use of cosolvents or excess TBA can achieve reasonable miscibility. The reaction mechanism is believed to be
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
and the surface reaction is limiting.
(d) Isobutene (I) and water (W) are adsorbed on different sites.
TBA is not on the surface, and the surface reaction is rate-limiting.
(e) What generalization can you make by comparing the rate laws derived in parts (a) through (d)?