The kinetics of the liquid phase hydrogenation of 4-tert-butylphenol to form cis-and trans-4-tert-butylcyclohexanol at 1 .O -10.0 MPa and 40 "C in isopropanol over a Rh catalyst has been studied. The kinetic behavior of this parallel system is described by a proposed reaction network. Keto-enol tautomeric transformation of adsorbed 4-tert-butyltetrahydrophenol and 4-tert-butylcyclohexanone is thought to be a key step, which governs the stereoselectivity of the overall complex reaction of alkylphenol hydrogenation.