Support effects of metal oxides on gold-catalyzed one-pot N-alkylation of amine with alcohol

Gold nanoparticles supported on metal oxides catalyzed the N-alkylation of aniline with benzyl alcohol to produce secondary amine under the equimolar amounts of substrates without additives under mild conditions. Selectivity to secondary amine was changed by the kinds of supports. Gold on ZrO2 exhibited the highest catalytic performance and achieved 94% selectivity to secondary amine. Surface hydroxyl groups of ZrO2 played important roles in the deprotonation of alcohol in the alcohol dehydrogenation step, as the adsorption sites of aniline, and as a proton source in the hydrogen transfer step.

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► Supported gold nanoparticles catalyzed one-pot N-alkylation of aniline with alcohol.
► Gold on ZrO2 exhibited the best catalytic activity and the selectivity.
► Zirconia might assist alcohol dehydrogenation, aniline adsorption, and hydrogen transfer.