Selective hydrogenation of paracetamol to acetamidocyclohexanone with silylated SiO2 supported Pd-based catalysts
Selective hydrogenation of paracetamol to acetamidocyclohexanone with silylated SiO2 supported Pd-based catalysts
复制标题
DOI：
10.1039/c6ra05479j
复制
发表时间：
2016-04
期刊：
影响因子：
3.9
通讯作者：
Song Wenjing;Xiuna Liu;Shaoyang Jiang;Zhou Chen;W. Weng;I. Rodríguez-Ramos;X. Yi;W. Fang
中科院分区：
文献类型：
--
作者：
Song Wenjing;Xiuna Liu;Shaoyang Jiang;Zhou Chen;W. Weng;I. Rodríguez-Ramos;X. Yi;W. Fang
采用湿法浸渍法制备了一系列Pd纳米粒子负载硅烷化二氧化硅催化剂，并用于对乙酰氨基酚选择加氢合成4-乙酰氨基环己酮的研究。采用TG、FT-IR、氮气物理吸附、TPR和XPS等手段对不同焙烧温度下的催化剂进行了表征。结果表明，在300℃焙烧后，有机改性后的催化剂表面仍由稳定的Si-(CH3)3物种组成，Pd粒子的大小和电子性质因载体上接枝基团的数量不同而发生变化。载体上较大的有机基团影响了扑热息痛分子的吸附方式，显著提高了4-乙酰氨基环己酮的选择性，并在一定程度上阻止了完全加氢反应。在500℃焙烧的硅烷化Pd催化剂上，对乙酰氨基环己酮的选择性为64.9%，对乙酰氨基环己酮的转化率为60.5%，而未硅化的SiO_2负载Pd催化剂的4-乙酰氨基环己酮选择性为29.1%，转化率为53.8%。
A series of catalysts comprising well-distributed Pd nanoparticles incorporated on silylated SiO2 were fabricated by the wet impregnation method and investigated in the selective hydrogenation of paracetamol to 4-acetamidocyclohexanone. The catalysts calcined at different temperatures were characterized by TG, FT-IR, N2 physisorption, TPR and XPS. The results showed that organic modification led to a catalyst surface composed of stable Si–(CH3)3 species even after calcination at 300 °C. Also, changes occurred in the size and electronic properties of the Pd particles through the different amounts of grafted groups on the SiO2 support. The mode of adsorption of the paracetamol molecule was influenced by the quite bulky organic groups on the support, resulting in a significant improvement in selectivity towards 4-acetamidocyclohexanone and preventing full hydrogenation to some extent. The best result was obtained on the silylated Pd catalyst calcined at 500 °C, with 64.9% selectivity to keto at the paracetamol conversion of 60.5%, while the non-silylated SiO2 supported Pd catalyst gave 4-acetamidocyclohexanone selectivity of 29.1% at 53.8% conversion.