Liquid phase isomerization of isoprenol into prenol in hydrogen environment

Supported Pd, Pt, Ru and Ir catalysts doped with Cd, Sn, P, Sb, Bi, Se, Ca and Ce have been studied in a liquid phase isomerization of 3-methyl-3-buten-1- ol (isoprenol) into 3-methyl-2-buten-1-ol (prenol) in a continuous reactor in the temperature range of 60-100 °C. Silica and different aluminas were used as supports. The catalyst containing 0.5% Pd-0.05% Se-0.3% Ce/SiO₂ exhibited the best performance. A 45% conversion of isoprenol at selectivity of 93-94% to prenol was recorded in 100 h run in hydrogen flow. The catalysts were characterized by SEM, XRD and XPS methods. The role of selenium consists in the stabilization of Pd in a partially oxidized state Pdⁿ⁺, depressing completely hydrogenation activity, and thus selenium promotes a shift of double bond. Addition of Ce oxide improves dispersion of palladium species affecting catalyst activity significantly.