Catalysts for the hydrogenation of adiponitrile (ADN) have been extensively studied, but achieving high selectivity of hexamethylenediamine (HMDA) in the absence of additional alkali inhibitors still poses many challenges. Herein, we fabricated nickel-based catalysts modified with Na additives for the liquid-phase hydrogenation of ADN in a fixed-bed reactor. The results showed that suitable weak acid sites are more conducive to enhancing the selectivity for HMDA, while stronger acid sites tend to promote the formation of higher amines. Moreover, the introduction of an appropriate amount of Na additive facilitates the dispersion of nickel, increasing the content of Ni⁰ species. Its electron-donating capacity to nickel aids in hydrogen adsorption and dissociation, thereby enhancing hydrogenation activity and favoring the selectivity for HMDA. Under optimal conditions of 120 °C and 4 MPa, improved catalytic performance with 100% ADN conversion and 82.07% HMDA selectivity were achieved over the Ni-0.15Na/Al₂O₃ catalyst.

中文翻译：

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Na 改性 Al2O3 负载镍基催化剂用于己二腈液相加氢：酸度的影响


己二腈（ADN）加氢催化剂已被广泛研究，但在没有额外碱抑制剂的情况下实现六亚甲基二胺（HMDA）的高选择性仍然面临许多挑战。在此，我们制备了用钠添加剂改性的镍基催化剂，用于固定床反应器中 ADN 的液相加氢。结果表明，合适的弱酸性位点更有利于增强HMDA的选择性，而较强的酸性位点则倾向于促进高级胺的形成。此外，适量Na添加剂的引入有利于镍的分散，提高了Ni ⁰ 物种的含量。其对镍的供电子能力有助于氢的吸附和解离，从而增强氢化活性并有利于HMDA的选择性。在120℃和4MPa的最佳条件下，与Ni-0.15Na/Al ₂ O ₃ 催化剂相比，催化性能得到了改善，ADN转化率达到100％，HMDA选择性达到82.07％ 。