INFLUENCE OF OPERATIONAL VARIABLES ON THE CATALYTIC BEHAVIOR OF PT ALUMINA IN THE SLURRY-PHASE HYDROGENATION OF PHENOL/

Hydrogenation of phenol in the liquid phase has been studied. The reac tion system was a stirred tank reactor with the catalyst-highly disper sed platinum/gamma-alumina prepared by adsorption from an aqueous solu tion of H2PtCl6-suspended as a slurry. In order to prevent the mass tr ansport steps to control the reaction rate, several experiments were c arried out varying stirring rate, catalyst particle size, and catalyst weight. In the studied conditions, working with stirring rate above 9 Hz, catalyst particle size below 50 mum, and catalyst weight below 0. 5 g assured the kinetic regime. The influence of pressure, temperature , and catalyst platinum content on both initial activity and selectivi ty was analyzed, for the chemically-controlled regime. Increasing tota l pressure was found to increase activity almost linearly and to decre ase selectivity. The apparent activation energies for phenol consumpti on and cyclohexanone and cyclohexanol formation (from phenol) were det ermined.