Liquid-Phase Catalytic Hydrogenation of 1,4-Cyclohexanedione: Activity and Selectivity

Article abstract of DOI:10.1021/jo01289a010

Liquid-phase catalytic hydrogenation of 1,4-cyclohexanedione was carried out by using various metal catalysts on SiO2 (Ni, Cu, Pd, Pt ,Ir, Ru) in 2-propanol as solvent under low hydrogen pressure, 6.2 bar, and 20 deg C.A kinetically consecutive process, diketone -> ketol -> diol, is obtained , and 4-hydroxycyclohexanone may be obtained in a single step at a yield of 70percent by utilizing Ru/SiO2.The rate and the selectivity for the first step of the reaction giving the ketol were examined as a function of several parameters: hydrogen pressure, substrate concentration, and temperature.The kinetic orders are 1 in H2 and -0.6 in diketone with an activation energy of 11 kcal/mol.