Facile synthesis of a nano titanium catalyst and its performance in selective oxidation of aromatic and pyridinic alcohols under visible light

The oxidation of alcohols to the corresponding carbonyl compounds is of great significance in chemical synthesis and fine chemical production. Traditional oxidants such as MnO2, chromium oxide, high-valent iodine, etc. will produce corresponding stoichiometric derivative waste when oxidizing alcohols. Polluting the environment does not conform to the concepts of green chemistry and atom economy. Herein, we successfully synthesized a small particle size 150-TiO2 by a simple solvothermal process in a hydrothermal reactor using tetrabutyl titanate, water, and ethanol as raw materials. Under visible blue light irradiation, the 150-TiO2 catalyst synthesized in this study exhibited the best catalytic activity and desirable product selectivity among commercial P25, anatase catalysts. Moreover, this catalyst has universality for the catalytic oxidation of different aromatic alcohol substrates, including the interesting pyridyl alcohols which are high-value chemicals for the preparation of pyridine aldehydes and ketones. The in situ facile synthesis heterogeneous catalyst 150-TiO2 not only has excellent stability and recyclability, but also broadly expands the application of green, atom-efficient, and sustainable photocatalytic oxidation of alcohols in pharmaceutical intermediates. Through characterization and result analysis, we confirmed that TiO2 adsorption of benzyl alcohol to form surface complexes is the key to achieving visible light response, and the high specific surface area of TiO2 is the key to achieving high catalytic activity.