Liquid-phase hydrogenation of dementholized peppermint oil on Pt/Al2O3 catalysts Part I: A study of catalyst performance

JUAN C. YORI; DEBORA MANUALE; ALBERTO J. MARCHI; JAVIER M. GRAU

APPLIED CATALYSIS A-GENERAL

Elsevier

Año: 2004 vol. 275 p. 221 - 226

0926-860X

The present work studies the catalytic hydrogenation of the ()-menthone fraction existing in a dementholized peppermint oil, subproduct of the low-temperature crystallization process of the Arvensis peppermint oil. The aim is to obtain a liquid menthol composition for commercial use that replacing the crystal form. Pt/Al2O3 catalysts with different metal content (1 and 4% Pt) were used and the effect of several operating variables is analyzed: H2 pressure, reaction temperature, and reactant mass/catalyst mass ratio. Total conversion values (()- menthone + (+)-isomenthone) in the order of 95% on the fresh catalyst after 4 h on-stream were obtained for 4%Pt/Al2O3. These conversion values decrease when the catalyst is reused, which is indicative of deactivation. When the Pt content is reduced, the total conversion values fall drastically. The ()-menthone to ()-menthol selectivity values are higher than 90% in every case.