Selective oxidation of alcohols to nitriles with high-efficient Co-[Bmim]Br/C catalyst system

Abstract

An efficient method for catalyzing the ammoxidation of aromatic alcohols to aromatic nitriles was developed, in which a new heterogeneous catalyst based on transition metal elements was employed, the new catalyst was named Co-[Bmim]Br/C-700 and then characterized by X-ray photo-electronic spectroscopy, transmission electron microscope and X-ray diffraction. The reaction was carried out by two consecutive dehydrogenations under the catalysis of Co-[Bmim]Br/C-700, which catalytically oxidized the alcohol to the aldehyde, and then the aldehyde was subjected to ammoxidation to the nitrile. The catalyst system was suitable for a wide range of substrates and nitriles obtained in high yields, especially, the conversion rate of benzyl alcohol, 4-methoxybenzyl alcohol, 4-chlorobenzyl alcohol and 4-nitrobenzyl alcohol reached 100%. The substitution of ammonia and oxygen for toxic cyanide to participate in the reaction accords with the theory of green chemistry.