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% trifluoroacetic acids at 298 K are determined by monitoring substrate consumption from the gas phase under the conditio ns of equilibrium substrate distribution between the gas phase and sol ution. The coefficients of isobutylene distribution are calculated alp ha = [i-C4H8](g)/[i-C4H8](s) at 298 K in the H2O-H2SO4, H2O-H3PO4, and H2O-HNO3 systems over the entire range of their compositions. On the basis of these findings, the data on the hydration rates in sulfuric a nd phosphoric acids obtained by the distribution methods are refined. The effect of the medium acidity on the reaction rate is quantitativel y described over a wide range of the acid concentrations.