Efficient catalytic amination of diols to diamines over Cu/ZnO/γ-Al2O3

•Continuous production of tetramethyl diamines via diols and dimethylamine.•Excellent catalytic performance for amination of diols over Cu/ZnO/γ-Al2O3–20.•The dispersion of metallic Cu was efficiently enhanced by the introduction of ZnO.•Internal relation between promotion effect and Zn content. Catalytic amination of diols with dimethylamine is a promising approach for the preparation of tetramethyl diamines. In this work, a series of Cu/ZnO/γ-Al2O3 catalysts were developed by co-precipitation and employed in the amination of 1,6-hexanediol (HDO) with dimethylamine (DMA) to N, N, N’, N’-tetramethyl-1,6-hexanediamine (TMHDA) in a fixed-bed reactor. Cu/ZnO/γ-Al2O3–20 exhibited remarkable catalytic performance. Nearly complete conversion of HDO was reached and 93% selectivity of TMHDA was obtained at 180 °C. The excellent catalytic performance was attributed to the highly dispersion of Cu, which was promoted by doped ZnO. The results of characterizations (TEM, H2-TPR, XRD, XPS, etc.) indicated that doped ZnO could efficiently decrease the average particle size and improve the dispersion of Cu. The promoting effect could be ascribed to strong interaction between Cu and ZnO. The availability and effectiveness of Cu/ZnO/γ-Al2O3 catalyst offer a prospective way for the industrial production of tertiary diamines through amination of diols. [Display omitted]