Gold nanoparticles deposited on surface modified carbon materials as reusable catalysts for hydrocarboxylation of cyclohexane

Gold nanoparticles were deposited on different carbon materials and used as catalysts for the alkane hydrocarboxylation reaction. Cyclohexane hydrocarboxylation to cyclohexanecarboxylic acid was carried out in the presence of CO and water, peroxodisulfate, in water/acetonitrile medium, at ca. 50 degrees C, with gold nanoparticles deposited by a colloidal method on carbon nanotubes and activated carbon with three different surface chemistries: in their original forms (CNT or AC, respectively), oxidized with HNO3 (ox) or oxidized with HNO3 and subsequently treated with NaOH (-ox-Na). Au/CNT-ox-Na was the best catalyst, yielding cyclohexanecarboxylic acid up to 88.2% yield, with excellent recyclability (97.5% of the initial activity was maintained after five consecutive catalytic cycles).