The reductive amination of cyclohexanone with 1,6-diaminohexane over alumina B modified Cu–Cr–La/γ-Al2O3

The reductive amination of cyclohexanone with 1,6-diaminohexane over alumina B modified Cu–Cr–La/γ-Al2O3 was investigated. The experimental results indicated that the doped alumina B remarkably increased the selectivity of N, N′-dicyclohexyl-1,6-diaminohexane. The catalysts were studied by BET, XRD, TEM and NH3-TPD, the introduction of alumina B to Cu–Cr–La/γ-Al2O3 reduced the strong acid capacity of the catalyst, which inhibited the generation of cyclohexane and 2-cyclohexylidene-cyclohexanone, and facilitated the desorption of amino compounds. The reaction parameters, including reaction temperature and molar ratio of starting materials, were optimized and a 92.6% selectivity of N, N′-dicyclohexyl-1,6-diaminohexane was obtained under optimized conditions.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► N, N'-dicyclohexyl-1,6-diaminohexane was obtained with a selectivity of 92.6%. ► Alumina B reduced the strong acid capacity of the catalyst. ► The low acidity increased the selectivity of N, N'-dicyclohexyl-1,6-diaminohexane. ► Hydrogenation of cyclohexanone includes irreversible and reversible process. ► The alumina B modified Cu-Cr-La/γ-Al2O3 exhibited excellent lifetime.