Efecto del solvente sobre la actividad catalítica en la hidrogenación de acetofenona sobre Ni/SiO2

A. TRASARTI; N.M. BERTERO; C.R. APESTEGUÍA; A. J. MARCHI

Buenos Aires

Congreso; XVI Congreso Argentino de Catálisis; 2009

The effect of solvent on the selective liquid-phase hydrogenation of acetophenone (AF) to 1-phenylethanol (FE) was studied on Ni/SiO2 catalyst. The solvents used had different nature: protic polar (alcohols C1-C3), aprotic polar (tetrahydrofurane, acetonitrile), and non polar (toluene, benzene, cyclohexane). A strong effect of the solvent on the catalytic activity was observed. However, selectivity to FE remains almost constant (higher than 85%) when changing the solvent. The initial hydrogenation rate pattern: alcohols C3-C2 > cyclohexane > toluene > tetrahydrofurane > methanol > benzene @ acetonitrilo was analyzed taking into account the effect of H2 solubility, solvent polarity, solvation ability, and the interactions solvent/catalyst. It was found that H2 solubility would not play any important role and was unable to explain the results. Even more, neither the polarity nor the solvation properties of the solvents are able to explain the whole catalytic activity pattern between solvent of mixed families. On the other hand, the interactions solvent/ catalyst, measured by the enthalpy of adsorption, provided strong evidence that, in some solvents, the key factor influencing the activity is solvent/catalyst interaction.2 catalyst. The solvents used had different nature: protic polar (alcohols C1-C3), aprotic polar (tetrahydrofurane, acetonitrile), and non polar (toluene, benzene, cyclohexane). A strong effect of the solvent on the catalytic activity was observed. However, selectivity to FE remains almost constant (higher than 85%) when changing the solvent. The initial hydrogenation rate pattern: alcohols C3-C2 > cyclohexane > toluene > tetrahydrofurane > methanol > benzene @ acetonitrilo was analyzed taking into account the effect of H2 solubility, solvent polarity, solvation ability, and the interactions solvent/catalyst. It was found that H2 solubility would not play any important role and was unable to explain the results. Even more, neither the polarity nor the solvation properties of the solvents are able to explain the whole catalytic activity pattern between solvent of mixed families. On the other hand, the interactions solvent/ catalyst, measured by the enthalpy of adsorption, provided strong evidence that, in some solvents, the key factor influencing the activity is solvent/catalyst interaction.