It is of great significance to develop an inexpensive and efficient catalyst to enhance the catalytic activity of oxidation coupling of alcohols with amines to imine. In this research, a series of manganese-iron bimetallic oxide catalysts have been prepared by a simple co-precipitation method, which were applied to the catalytic reaction of oxidation coupling of benzyl methanol with aniline to N-benzylideneaniline. The effects of different Fe/Mn feed ratios on the catalytic activity of the products have been explored. The Mn_0.5Fe_0.5O_x sample with a Fe/Mn feed ratio of 1:1 demonstrated the best catalytic activity, giving an aniline conversion rate of 74.7%, 99.9% selectivity and 74.6% yield of N-benzylidene, respectively. Through a variety of characterizations, Mn_0.5Fe_0.5O_x exhibited rich mesoporous structure and surface adsorbed oxygen species, as well as excellent oxidation ability. The high-efficiency catalyst synthesized in this work has great application potential in the preparation of imines by oxidation coupling of alcohols with amines.

In this research, β-MnO₂ nanorods enriched with surface oxygen vacancies were successfully fabricated through a facile quenching strategy using pristine β-MnO₂ nanorods as the precursor. The quenched samples were applied as the catalysts for the selective oxidation of cinnamyl alcohol to cinnamaldehyde. By varying the calcination temperature, the influence of surface structure of quenched β-MnO₂ nanorods on their catalytic performance was investigated.The results showed that the catalytic activities of quenched β-MnO₂ nanorods were significantly better than those of the precursor and naturally cooled β-MnO₂ nanorods after calcination. Notably, the β-MnO₂ nanorods calcined at 350 ℃ followed by rapid cooling achieved the highest catalytic performance, with a cinnamyl alcohol conversion of 53.1% and a cinnamaldehyde selectivity of 95.2%, outperforming several commercial non-noble metal oxides. Various physicochemical characterizations demonstrated that the quenching technique could enhance the surface lattice oxygen activity and oxidation ability of β-MnO₂ nanorods, thereby effectively boosting their catalytic oxidation performance. This work demonstrates that quenching technique has a positive effect on increasing the surface oxygen vacancy concentration and catalytic performance of MnO₂, which offers an effective strategy for designing the high-efficiency non-noble metal oxide catalysts.