Low cost and non-surfactant synthesis of fluorinated alumina modified with magnesium for condensation of aniline to diphenylamine

Fluorinated alumina was modified with different alkaline and alkaline earth metals. And fluorinated alumina modified with magnesium was found to show the best reactivity and selectivity for condensation of aniline to diphenylamine (DPA) under fix-bed continuous flow reaction conditions. Various characterizations involving X-ray diffraction, nitrogen-adsorption measurements, inductive coupled plasma emission spectrum as well as infrared spectrum has integrally testified the structure of fluorinated alumina modified with magnesium. The preparation of fluorinated alumina modified with magnesium was simply convenient and, importantly, environmentally benign for non-surfactant needed in comparison with H-beta zeolite. Meanwhile, the catalyst even exhibited higher conversion of aniline than H-beta zeolite. Such alumina-based catalyst can be readily recovered for at least 5 times, while the conversion of aniline and productivity for DPA was almost maintained during the reaction.