Phenol alkylation with methanol: effect of sodium content and ammonia selective poisoning of an HY zeolite

Abstract:

Sodium exchange and ammonia selective poisoning of the acid sites of an HY zeolite (Si/Al=20) were carried out and their effects on the catalytic properties for the alkylation of phenol with methanol (200‡C, 1 atm and N2/reactants molar ratio of 4) were evaluated. Results show that the reaction is highly sensitive to the number and strength of the acid sites of the catalyst. A decrease in the number of acid sites by sodium exchange of the protons or by ammonia selective poisoning produces important changes in the selectivity of the reaction. In fact, a high increase in the anisole/cresol ratio is observed as the percentage of exchanged sodium in the zeolite increases, while the ammonia selective poisoning shows that at low desorption temperatures (⩽250‡C) only anisole is formed while at higher desorption temperatures both anisole and cresols were observed. These results show that anisole formation …

Año de publicación:

1996

Keywords:

Fuente:

google