Synthesis of 3-picoline from acrolein dimethyl acetal and ammonia over NH4F-HF treated ZSM-5

The post-treated ZSM-5 was an effective catalyst for the synthesis of pyridine bases and therefore selecting suitable post-synthetic method was very crucial. In this work, a series of Mg-modified ZSM-5 with different forms was directly treated by HF-NH4F mixture solution, and then they acting as catalysts were for the first time employed for the reaction of acrolein dimethyl acetal, water and ammonia toward 3-picoline. The catalysts were characterized by means of XRD, SEM, EDX, FT-IR, Al-27 MAS NMR, N-2-physisorption, NH3-TPD and Py-IR techniques. The characterization results revealed that the fluorination had a great influence on the pore structure and acidity of catalysts, deriving from the simultaneous desilication and dealumination. These factors resulted in large changes on the catalytic activities toward the modified catalysts than the corresponding to parent ones.