NaY分子筛固载席夫碱钴配合物的制备、表征及其催化性能研究

NaY分子筛固载席夫碱钴配合物的制备、表征及其催化性能研究

  • 摘要: 利用“瓶中造船”(ship-in-a-bottle) 技术将双水杨醛缩乙二胺合钴(Cosalen)配合物封装于Y型沸石分子筛的超笼中,制备出固载型席夫碱钴金属配合物Cosalen/Y(SB)。同时采用浸渍方法将Cosalen负载于Y型分子筛的表面,制备了浸渍型的负载物Cosalen/Y(IM)。采用原子吸收、红外光谱、紫外光谱、X射线衍射、热重差热和电镜扫描等方法对两者进行了表征。 结果表明 ,固载物Cosalen/Y(SB)中Cosalen已成功地进入了分子筛的孔道内。以分子氧为氧源,考察了Cosalen/Y(SB)对环己烷的催化氧化性能以及催化剂用量、溶剂、氧气压力对反应的影响。结果表明,Cosalen/Y(SB)具有较高的催化氧化活性和对环己醇、环己酮以及己二酸的选择性,有一步氧化环己烷生成己二酸的潜力。重复实验表明,催化剂稳定性较好,没有明显的活性组分流失。

     

    Abstract: N,N’-Bis(salicylidene)ethylenediiminocobalt (Cosalen) was encapsulated into the supercage of microporous NaY zeolite via “ship-in-a-bottle” technique, which was compared with the impregnated Cosalen complex immobilized on the outer surface of the zeolite to prove the encapsulation. The samples were characterized by AAS, FT-IR, UV-Vis, XRD, TG-DTA and SEM techniques. The oxidation of cyclohexane with oxygen was chosen to evaluate the catalytic performance of the encapsulated complex. The effects of catalyst usage, solvent and initial oxygen pressure on the oxidation reaction were investigated. The encapsulated complex Cosalen/Y(SB) exhibited high catalytic activity for cyclohexane oxidation and high selectivity to cyclohexanol, cyclohexanone and adipic acid in the CH3CN solution without adding any inducing agents, which suggested that the catalyst is potential for the oxidization of cyclohexane into adipic acid. Moreover, the catalyst exhibited excellent stability and could be reused without obvious loss of the active components.

     

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