Abstract: In this paper, NaX zeolite was modified with Ce ions by liquid phase ion exchange method. After comparing the catalytic effects of Ce(III)X and Ce(IV)X, the effect of ion occupation and valence state on cyclohexane oxidation were investigated under different ion exchange rates and different calcination atmosphere. The modified catalysts were characterized by ICP, XRD, BET, XPS, H2-TPR. The results showed that the conversion of cyclohexane on Ce(III)X was 2.6 times higher than that on NaX, and slightly higher than that on Ce (IV) X; the conversion of cyclohexane was increased from 3.15% to 8.54% with the Ce(III)X ion occupation increasing from 13.4% to 76.2%, and the conversion of cyclohexane was reduced to 7.5% and 5.7% with Ce(III)X calcinated in vacuum and air, respectively. The reduction of catalytic activity was related to the migration of Ce(III) ions to sodalite cages and valence variation. At the same time, the optimum process conditions were obtained: oxygen pressure was 1.5 MPa, reaction temperature was 150℃, stirring speed was 800 r/min, and reaction time was 2 hours. The conversion of cyclohexane was 8.54%, and the selectivity of target products (cyclohexanone and cyclohexanol) was 86.39% under the optimum process conditions.

Key words: CeX molecular sieve, ion exchange method, calcination atmosphere, cyclohexane oxidation