Novel magnetic-separable and efficient Au/Fe–Al–O composite for the lactonization of 1,4-butanediol to γ-butyrolactone

Abstract

Nano-sized gold catalysts have attracted much interest during recent years. Here, we report a new material to improve the catalytic activity and recyclability of gold catalysts. Multi-component Fe–Al–O oxides prepared by impregnation (γ-Fe₂O₃/γ-Al₂O₃ and Al₂O₃/α-Fe₂O₃) and encapsulation (Fe₂O₃@Al₂O₃) methods were employed as carriers for gold catalysts. The Au/Fe–Al–O composites exhibited efficient catalytic activity and selectivity for the lactonization of 1,4-butanediol to γ-butyrolactone. They could also be easily recovered due to their super-paramagnetic property. XRD, TEM, XPS and H₂-TPR were used to characterize the composites. The influence of surface Fe/Al ratio on Au/(Fe₂O₃@Al₂O₃) composites was also studied by adjusting the Fe/Al molar ratio for comparison and the optimal Fe/Al ratio was found to be 1 : 4. The results confirmed that higher conversion and selectivity were obtained due to the bifunctional effect of Fe₂O₃ and Al₂O₃.