Kinetics of Isobutylene Hydration Over a Wide Range of Medium Acidity: Effect of the Substrate Solubility

The rate constants of isobutylene hydration in 19-40% sulfuric, 20-64% phosphoric, and 59% tri-fluoroacetic acids at 298 K are determined by monitoring substrate consumption from the gas phase under the conditions of equilibrium substrate distribution between the gas phase and solution. The coefficients of isobutylene distribution are calculated α = [i-C ₄ H ₈ ] _g /[i-C ₄ H ₈ ] _s at 298 K in the H ₂ O-H ₂ SO ₄ , H ₂ O-H ₃ PO ₄ , and H ₂ O-HNO ₃ systems over the entire range of their compositions. On the basis of these findings, the data on the hydration rates in sulfuric and phosphoric acids obtained by the distribution methods are refined. The effect of the medium acidity on the reaction rate is quantitatively described over a wide range of the acid concentrations.