FeAlPO-34 molecular sieves with controllably high iron contents: ionothermal synthesis and catalytic performance in phenol hydroxylation

FeAlPO-34 molecular sieves with tunable iron contents were synthesized in a 1-butyl-3-methylimidazolium bromide [BMIm] Br ionic liquid. The added Fe 3+ was successfully incorporated into the AlPO-34 framework, which mainly presents in tetrahedral and octahedral sites in the framework, with up to 10.28 wt.% of isolated iron contents. The iron contents directly influenced the crystal size and morphology, mesoporous properties. A sample with relatively high iron contents and a hierarchical structure shows excellent catalytic performances when utilized as the catalyst of phenol hydroxylation reaction. The sample with 6.09 wt.% Fe showed a 41.55% of phenol conversion with the selectivity of 92.72 to hydroquinone and catechol.