Effect of surface acidity and basicity of supported Ni catalysts on the N-alkylation of isopropylamine with isopropanol,Reaction Chemistry & Engineering

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Effect of surface acidity and basicity of supported Ni catalysts on the N-alkylation of isopropylamine with isopropanol
Reaction Chemistry & Engineering ( IF 3.4 ) Pub Date : 2021-11-19 , DOI: 10.1039/d1re00437a
Shaozhong Li ₁ , Qing Guo ₁ , Jin Li ₁ , Yongke Hu ₁

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The N-alkylation of amines with alkylating reagents is widely used in the synthesis of aliphatic amines, which is usually catalyzed by homogeneous catalytic systems. In this work, the heterogeneous catalysts Ni/AlSiO (NAS), Ni/LaAlSiO (NLAS) and Ni/LaO (NL) with different strengths of acidity and basicity were used in the N-alkylation of isopropylamine (IPA) with isopropanol (IPO) to diisopropylamine (DIPA) in a fixed-bed reactor, and the effect of surface acidity and basicity of the supported Ni catalysts on the N-alkylation was studied by microcalorimetric adsorption and in situ Fourier transform infrared spectra. It was found that the surface acidity and basicity of the supported Ni catalysts affected the adsorption and interaction of IPO, IPA and DIPA on the supported Ni catalysts, and IPO and IPA molecules were strongly adsorbed onto the strong acidic surface, which would improve the N-alkylation reaction. In addition, the generation of imine species from the dehydrogenation of IPA greatly decreased the activity of the N-alkylation reaction, and the strong adsorption of dissociated H from the adsorption of IPO, IPA or DIPA on acidic surface inhibited the generation of imine species, which promoted the conversion of IPA. Meanwhile, the strong adsorption of dissociated H on acidic surface also promoted the hydrogenation of diisopropylimine, which increased the selectivity to DIPA.

中文翻译：

负载型镍催化剂表面酸碱度对异丙胺与异丙醇N-烷基化反应的影响

胺与烷基化试剂的N-烷基化广泛用于脂肪胺的合成，通常由均相催化体系催化。在这项工作中，将具有不同酸碱度的多相催化剂 Ni/AlSiO (NAS)、Ni/LaAlSiO (NLAS) 和 Ni/LaO (NL) 用于异丙醇 (IPO) 对异丙胺 (IPA)的N-烷基化反应。 ) 在固定床反应器中转化为二异丙胺 (DIPA)，并通过微量热吸附和原位研究了负载型 Ni 催化剂的表面酸碱度对N-烷基化反应的影响。傅里叶变换红外光谱。发现负载Ni催化剂的表面酸性和碱性影响IPO、IPA和DIPA在负载Ni催化剂上的吸附和相互作用，IPO和IPA分子强烈吸附在强酸性表面上，这将提高N -烷基化反应。此外，IPA 脱氢产生的亚胺物种大大降低了N的活性。-烷基化反应，IPO、IPA或DIPA吸附在酸性表面上的强烈吸附解离的H抑制了亚胺物种的生成，从而促进了IPA的转化。同时，游离H在酸性表面的强吸附也促进了二异丙基亚胺的加氢，从而提高了对DIPA的选择性。

更新日期：2021-12-10

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