Amorphous aluminophosphates are industrial catalysts that are active in aldol-type condensations, dehydration and alkylation. The intrinsic nature of the active sites present in these materials is poorly understood. Herein we report a comparative investigation of the catalytic active sites in amorphous and crystalline aluminophosphates (AFI topology) and their corresponding iron-containing analogues, employing Claisen-Schmidt condensation of acetophenone and benzaldehyde as the test reaction. Secondary porosity generated via the soft-templating approach in hierarchically-porous HP FeAlPO-5, and the presence of large mesopores in amorphous Am FeAlPO resulted in improved mass-transport and high conversion of carbonyls. The nature and concentration of the active acidic sites within these materials were characterized by pyridine-DRIFTS and propylamine-TPD studies and was shown to play a crucial role in the activation of carbonyl groups and better catalytic performance. Am FeAlPO(5) nearly outperformed HP FeAlPO-5, thus providing a promising alternative for expanding scope in industrial and pharmaceutical applications.

无定形铝磷酸盐是工业催化剂，在醇醛型缩合、脱水和烷基化中具有活性。这些材料中存在的活性位点的内在性质知之甚少。在此，我们报告了对无定形和结晶铝磷酸盐（AFI 拓扑结构）及其相应含铁类似物的催化活性位点的比较研究，采用苯乙酮和苯甲醛的 Claisen-Schmidt 缩合作为测试反应。在分层多孔 HP FeAlPO-5 中通过软模板方法产生的二次孔隙率，以及无定形 Am FeAlPO-5 中大中孔的存在导致传质得到改善和羰基化合物的高转化率。这些材料中活性酸性位点的性质和浓度由吡啶-DRIFTS 和丙胺-TPD 研究表征，并显示在羰基的活化和更好的催化性能方面起着至关重要的作用。Am FeAlPO(5) 几乎优于 HP FeAlPO-5，从而为扩大工业和制药应用的范围提供了一个有前景的替代方案。