光照及需氧条件下Al_2O_3-AlBr_x催化醇的选择性氧化反应

Selective Oxidation of Alcohols Catalyzed by Al_2O_3-AlBr_x Under Aerobic and Light Conditions

以脱脂棉为模板制备了多孔管状结构的Al2O3材料,用不同浓度的氢溴酸对多孔管状结构的Al2O3材料进行化学剪裁,制备了活性量可控,比表面积可调,不同形貌的负载型催化剂Al2O3-AlBr x。采用电场发射扫描电镜(SEM)和X射线衍射仪(XRD)对催化剂进行了表征。结果表明,该催化剂较好地复制了棉纤维的宏观和微观结构,呈现出明显的生物形貌特征。在光照条件下以空气为氧化剂的醇的选择性氧化反应中,发现催化剂Al2O3-AlBr x-3可以高选择性地将醇氧化为相应的醛、酮或酸,并对反应机理进行了探讨。该催化剂循环使用3次仍保持较高的催化活性。

Al2O3 material with cribrate tubular structure was prepared through immersion method with absorbent cotton as moldboard and was clipped chemically by HBr acid solution of different concentration. The catalyst Al2O3-AlBrx with controlled activity, adjustable specific surface area and different feature was prepared successfully, and was characterized by means of scanning electronic microscope and X-ray diffraction. The results show that the catalyst copied the macroscopic and microscopic structure of the cotton fiber in a desirable way and showed the characteristics of typical biological morphology. Under lighting condition, we found that Al2O3-AlBrx-3 was available for the oxidation of alcohol into corresponding aldehyde, ketone or acid with higher conversion and selectivity using air as an oxidant, thus proposing a plausible mechanism. Al2O3-AlBrx-3 was reeyclable, still maintaining high catalytic activity after using three times.