氮杂冠醚取代单Schiff碱过渡金属配合物催化氧化对二甲苯研究

本文将苯并-10-氮杂-15-冠-5或吗啉基取代的单Schiff碱过渡配合物作为催化剂,在常压和120℃条件下,以空气为氧源,研究了对二甲苯催化氧化反应。实验探讨了Schiff碱配合物中心金属离子、Schiff碱配体中挂接的氮杂冠醚环、配体芳环上取代基和反应时间等对对二甲苯催化氧化反应的影响。实验结果表明:Schiff碱配合物中氮杂冠醚的存在能显著缩短反应诱导期,提高催化反应活性和产物选择性;Schiff碱Mn(III)配合物比Schiff碱Co(II)具有更高的催化反应活性;氮杂冠醚Schiff碱Mn(III)配合物对于二甲苯的催化氧化反应转化率大于60%,对甲苯甲酸产物的选择性均高于70%。

Study on catalytic oxidation for p-xylene to p-toluic acid by mono-Schiff base complexes with pendant aza-crown ether

mono-Schiff base complexes with pendant aza-crown or morpholino groups had been studied as catalysts in aerobic oxidation of p-xylene to p-toluic acid(PTA)with air at 120℃ under normal atmospheric pressure.The effects of central metal of Schiff base complexes,the aza-crown ether group pendant and the substituents group in Schiff base ligands and the reaction time on the oxidation of p-xylene were also investigated.The results revealed that the catalytic activity of mono-Schiff base complexes binding aza-crown ether pendants could be visibly improved and the induce period of the oxidation for p-xylene to p-toluic acid was shortened.Schiff base manganese(III)complexes had higher catalytic activity than cobalt(II)complexes under the same ligand.Significant selectivity(up to～70%)and conversion levels(up to～60%)were obtained in the presence of aza-crown ether substituted mono-Schiff base Mn(III)complexes.