EFECTO DEL SOLVENTE EN LA OXIDACIÓN DE ALCOHOLBENCÍLICO SOBRE ZnO/MnCO3. INFLUENCIA DE LOS PARÁMETROS SOLVATOCRÓMICOS SOBRE LA CINÉTICA DE REACCIÓN.

JUAN ZELÍN; HERNÁN DUARTE; PABLO JORGE LUGGREN; MARÍA EUGENIA SAD; VERÓNICA DIEZ; ISABEL DI CÓSIMO

Congreso; XXVIII CONGRESSO IBERO-AMERICANO DE CATÁLISE; 2022

The relationship between the physicochemical properties solvent and catalytic activity of a ZnO/MnCO3catalyst in the aerobic oxidation of benzyl alcohol (BA) to benzaldehyde (B) was studied. Polar aprotic solvents (dibutyl ether, dioxane, dibenzyl ether and dimethyl sulfoxide) and no polar solvents (heptane, toluene and ethyl benzene) were used. The solvent had a significant influence on the catalytic activity,obtaining the following activity pattern: ethyl benzene > toluene > dibenzyl ether > heptane  dioxane > dibutyl ether = dimethyl sulfoxide. However, the nature of the solvent showed no difference in the selectivity to benzaldehyde which ranged from 95% to 99%. In order to explain the activity pattern, physicalparameters, solvatochromic scale and adsorption enthalpies (Hads) of the solvent on the catalyst were studied. For polar solvents, the catalytic activity decreased with the increase of the parameter representing the hydrogen bonding acceptance capacity (SB). In contrast, for non-polar solvents, an increase in activity was observed with increasing SB. An increase in solvent polarity/polarizability index resulted in an increase in catalytic activity, while the low Hads values measured for all the studied solvents suggested that the strength of the solvent-catalyst interaction is negligible compared to that of the AB-solvent interaction.