In this work, a facile route was developed for the preparation of amine-functionalized magnetite nanoparticles by co-precipitation method. These amine-functionalized magnetite nanoparticles were sulfonated and then used as novel heterogeneous acid catalyst and their catalytic activities were investigated in the green synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes under thermal and solvent free conditions. The catalyst was characterized by FT-IR, SEM, EDX, XRD, TGA and VSM. Also, the catalyst could be recovered easily and reused several times without any significant loss of its catalytic activity.

中文翻译：

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有效制备胺官能化的纳米磁铁矿作为新型固体酸催化剂的前体，用于在无溶剂条件下一锅合成黄嘌呤

在这项工作中，开发了一种通过共沉淀法制备胺官能化磁铁矿纳米粒子的简便途径。这些胺官能化的磁铁矿纳米粒子被磺化，然后用作新型多相酸催化剂，并在无热和无溶剂条件下绿色合成14-芳基-14H-二苯并[a，j]氧杂蒽时研究了它们的催化活性。通过FT-IR，SEM，EDX，XRD，TGA和VSM对催化剂进行了表征。而且，该催化剂可以容易地回收并重复使用几次，而其催化活性没有任何重大损失。