Abstract: A series of modified ZSM-5 catalysts for 2,6-lutidine synthesis through catalytic amination of acetone and methanol were prepared by a transition metal doping method. The catalyst 6%Pb-0.5%Fe-0.5%Co/ZSM-5(200) with good performance in the reaction was selected on a fixed-bed reactor. The reasons for the improvement of the catalyst performance by doping transition metals into ZSM-5 were discussed. The effects of reaction temperature, molar ratio of ammonia to methanol, composition of raw materials, and residence time on the catalytic performance of the catalyst were studied. Acetone conversion and 2,6-lutidine yield reached 67.6% and 40.3%, respectively, when the reaction was run at 450 °C for 20 h under the conditions of atmospheric pressure, the molar ratio of ammonia to acetone to methanol of 2:2:1, the volume content of water of 40%, and the residence time of 5.5 s. With the time extension, the performance of the catalyst got deterioration gradually and the yield of 2,6-lutidine dropped to 23% after a time on stream of 42 h. The catalyst activity could be recovered largely by air oxidation on line. The possible reasons for the deterioration of the catalyst performance were discussed.

Key words: 2,6-lutidine, methanol, acetone, ammoniation, lead, iron, cobalt, ZSM-5 zeolite