Rh-Mn-Li/SiO2催化剂上CO加氢制C2含氧化合物:载体硅烷化程度的影响

以三甲基氯硅烷为硅烷化试剂,对硅胶进行不同程度硅烷化预处理,采用浸渍法制备了其负载的Rh-Mn-Li催化剂,用于CO加氢制C₂含氧化合物的反应,并运用红外光谱、N₂吸附-脱附法、C含量测定、透射电镜、H₂程序升温还原和程序升温表面反应等手段对载体和催化剂进行了表征。结果表明,制得的不同硅烷化程度硅胶织构性质变化不大,它们负载的催化剂上Rh平均粒径均在3nm左右,硅烷化对催化剂吸附CO的形态和Rh的还原性能的影响均很小,但随着载体硅烷化程度的提高,催化剂上Rh解离CO的能力增加,因而其活性逐渐增加,且不影响C₂含氧化合物的选择性。

Rh-Mn-Li/SiO2 catalyst for CO hydrogenation to C2 oxygenates:Effect of support silanization degree on its catalytic performance

Silica was treated with trimethylchlorosilane before using as the supports for Rh-Mn-Li catalysts in CO hydrogenation to C₂ oxygenates. The catalysts were characterized by infrared spectroscopy, N₂ adsorption-desorption, C content measurements, transmission electron microscopy, H₂ temperature programmed reduction, and temperature programmed surface reaction. The results showed that the silanization degree has little effect on the textural properties of silica. The mean Rh particle size (about 3nm), CO adsorption state on Rh and reducibility of Rh supported on silica remain unchanged by the silanization of silica support. However, with an increase of the silanization degree of silica, the ability of Rh to dissociate CO is improved, which can enhance the catalytic activity of Rh-Mn-Li/SiO₂ in CO hydrogenation but has little influence on the selectivity towards C₂ oxygenates.