Hydrogenation of 2,2,6,6-Tetramethylpiperidin-4-one over Cu30Cr5/Basic Alumina

Alumina B (basic alumina, pH > 8) was used as the support of copper-chromium catalysts for continuous hydrogenation of 2,2,6,6-tetramethylpiperidin-4-one (TAA) to 2,2,6,6-tetramethylpiperidin-4-ol (TMP). It was found that Cu30Cr5/alumina B exhibited better catalytic performance than Cu30Cr5/γ-Al2O3. 99.0% conversion of TAA and 97.2% selectivity for TMP were obtained over Cu30Cr5/alumina B under optimized conditions. Cu30Cr5/γ-Al2O3 and Cu30Cr5/alumina B were characterized by N2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, and NH3 temperature-programmed desorption. The results showed that Cu particles dispersed better in Cu30Cr5/alumina B than in Cu30Cr5/γ-Al2O3.

摘要在2,2,6,6-四甲基哌啶酮连续化加氢生成 2,2,6,6-四甲基哌啶醇的反应中, Cu30Cr5/碱性氧化铝比Cu30Cr5/γ-Al2O3 具有更优异的催化性能, 反应的转化率和选择性分别高达 99.0% 和 97.2%. N2 物理吸附-脱附、X 射线光电子能谱、X 射线衍射和氨气程序升温脱附结果表明, Cu0 作为催化加氢反应的活性中心, 在 Cu30Cr5/碱性氧化铝中具有更好的分散性, 且随着碱性氧化铝的引入, 催化剂酸性大幅下降, 从而有效抑制副产物 2,6-二甲基-4-庚酮的生成, 因而产物 2,2,6,6-四甲基哌啶醇的选择性显著提高.

Graphical abstractCu particles in Cu30Cr5/basic alumina (alumina B) dispersed better compared with Cu30Cr5/γ-Al2O3 and the acidic capacity of the support decreased. These resulted in higher selectivity and conversion.Figure optionsDownload full-size imageDownload as PowerPoint slide