Abstract:

Magnetic CuO-Bi₂O₃/Fe₃O₄-SiO₂-MgO catalysts with different Cu content were prepared by using impregnation and coprecipitation methods. The obtained catalysts were characterized by atomic emission spectrometer (ICP-AES), N₂ absorption, X-ray diffraction (XRD), H₂ temperature-programmed reduction (H₂-TPR) and vibrating sample magnetometer (VSM). Their catalytic performance for formaldehyde ethynylation was evaluated. The results indicated that preparation method showed a great influence on the CuO station in catalysts, thus, on the performance for formaldehyde ethynylation reaction. Compared with the catalysts prepared by impregnation, the CuO-Bi₂O₃/Fe₃O₄-SiO₂-MgO catalysts prepared by co-precipitation method showed higher CuO dispersion and better reducibility, so had better catalytic activity and selectivity. Moreover, Cu content was another important factor affecting catalyst activity. With Cu content increasing, the catalyst activity increased gradually. In the present work, 30% (mass) Cu loading catalyst prepared by co-precipitation method showed the highest catalytic activity. In addition, this catalyst was of good superparamagnetism and stability, so easy separated by external magnetic field for reuse. After six cycles, its stability was much better than non-paramagnetism CuO-Bi₂O₃/SiO₂-MgO catalyst.

Key words: separation, recovery, catalysis, formaldehyde ethynylation, 1,4-butynediol, magnetic

摘要：

采用浸渍法和共沉淀法制备了一系列不同Cu含量的超顺磁CuO-Bi₂O₃/Fe₃O₄-SiO₂-MgO催化剂。使用电感耦合等离子体发射光谱仪(ICP-AES)、低温N₂物理吸-脱附、X射线衍射(XRD)、H₂程序升温还原(H₂-TPR)、振动样品磁强计(VSM)对催化剂的组成、结构、织构及磁性能进行表征, 评价了该催化剂催化甲醛乙炔化合成1, 4-丁炔二醇的催化活性。结果表明, 制备方法对催化剂中活性组分CuO的存在状态及炔化性能有较大影响, 采用共沉淀法较浸渍法制备的催化剂具有更高的比表面积、CuO分散度与较好的还原能力, 表现出较高的炔化性能;Cu含量是影响催化剂炔化性能的另一重要因素, 随Cu含量的增加, 催化剂活性逐渐增加, 在本研究考察范围内, 以共沉淀法制备的Cu质量分数为30%的催化剂表现出最佳的甲醛乙炔化性能。同时, 该催化剂具有良好的超顺磁性, 可以在外加磁场的作用下迅速分离回收, 循环使用6次后, 其催化活性明显高于非磁性催化剂。

关键词: 分离, 回收, 催化, 甲醛乙炔化, 1, 4-丁炔二醇, 磁性