Cr and Co-modified Cu/Al2O3 as an efficient catalyst for the continuous synthesis of bis(2-dimethylaminoethyl)ether

Abstract

A series of transition metal-doped Cu-based Al₂O₃ catalysts were prepared by a coprecipitation–kneading method, and applied in the continuous synthesis of bis(2-dimethylaminoethyl)ether (BDMAEE) via amination of diethylene glycol (DEG) with dimethylamine (DMA), in which Cu–Cr–Co/Al₂O₃ exhibits desirable catalytic performance toward BDMAEE. Multiple characterization methods including XRD, TEM, H₂-TPR, N₂O chemisorption, XPS, NH₃-TPD, and FTIR of adsorbed pyridine were employed to investigate the structure–activity relationship. Compared with Cu/Al₂O₃, co-doping Cr and Co into Cu/Al₂O₃ can promote the dispersion of Cu nanoparticles and regulate the acidity of the catalyst. Therefore, superior Cu dispersion facilitates the amination of alcohols with DMA, and the appropriate acidity of the catalyst promotes its catalytic selectivity towards BDMAEE, resulting in desirable yields. Moreover, Cu–Cr–Co/Al₂O₃ exhibits good stability. This work provides a promising way for the continuous industrial production of BDMAEE and its derivatives via catalytic amination of alcohols.