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.

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► 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.