Pd(ii) immobilized on mesoporous silica by N-heterocyclic carbene ionic liquids and catalysis for hydrogenation
作者:Gang Liu、Minqiang Hou、Tianbin Wu、Tao Jiang、Honglei Fan、Guanying Yang、Buxing Han
DOI:10.1039/c0cp01213k
日期:——
In this work we synthesized Pd(II) immobilized on mesoporous silica by N-heterocyclic carbene (NHC) ionic liquids (ILs) with different alkyl chain lengths. The catalysts were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), low-angle X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen sorption. The catalysts were used for the hydrogenation of alkenes and allyl alcohol. The results indicated that the catalysts were very active, selective, and stable. The selectivity for the hydrogenation of allyl alcohol to 1-propanol increased with the increase of the alkyl chain length of the ILs. The effect of supercritical CO2 (scCO2) on the hydrogenation of allyl alcohol was also studied, and it was demonstrated that scCO2 could enhance the selectivity of the reaction considerably. The XPS study showed that the valence of Pd(II) remained unchanged under hydrogenation conditions.
在这项工作中,我们通过具有不同烷基链长度的N-杂环卡宾(NHC)离子液体(ILs)合成了固定在介孔二氧化硅上的Pd(II)催化剂。通过傅里叶变换红外光谱(FT-IR)、热重分析(TGA)、低角X射线粉末衍射(XRD)、透射电子显微镜(TEM)、X射线光电子光谱(XPS)和氮吸附等方法对催化剂进行了表征。这些催化剂被用于烯烃和烯丙醇的加氢反应。结果表明,这些催化剂具有很高的活性、选择性和稳定性。烯丙醇加氢生成1-丙醇的选择性随着ILs烷基链长的增加而增加。还研究了超临界二氧化碳(scCO2)对烯丙醇加氢反应的影响,结果证明scCO2可以显著提高反应的选择性。XPS研究显示,在加氢条件下Pd(II)的价态保持不变。