| 刘菁,$2.（PdCl2—PVP）／Al2O3催化剂中Pd状态的探讨[J].分子催化,1992,(1):32-37 |
| （PdCl2—PVP）／Al2O3催化剂中Pd状态的探讨 |
| An Examination on the Active State of Pd in (PdCl2-PVP)/Al2O3 Catalyst |
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| DOI： |
| 中文关键词: 钯 络合物 催化剂 催化加氢 烯烃 |
| 英文关键词:Polyvinylpyrrolidone, Palladium complex catalyst, Catalytic hydrogenation, Alkene |
| 基金项目: |
| 刘菁 $2 |
| 中国科学院大连化学物理研究所，中国科学院上海有机化学研究所，金属有机化学开放实验室，中国科学院大连化学物理研究所催化基础国家重点实验室，中国科学院大连化学物理研究所催化基础国家重点实验室 大连 116023，上海 200032，大连 116023，大连 116023 |
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| 中文摘要: |
| 氯化钯先锚定在聚乙烯吡咯烷酮上后进一步负载到Al_2O_3上所制的催化剂[简称(PdCl_2-PVP)/Al_2O_3]是一种活性、选择性高,稳定性好的烯烃、二烯烃和多烯烃加氢催化剂。本文结合加氢反应,使用XPS、FT-IR、电镜及用CO为探针的FT-IR,对这种催化剂进行了考察。实验说明,在这种催化剂中,钯的价态是在0—2之间。红外光谱在486cm~(-1)处有一微弱的小峰,说明存在Pd—N的配位键。催化剂中钯含量低时(0.2wt％)稳定性好,不吸附CO,活性中心是络合钯原子;当钯含量较高时(0.7wt％),催化剂的初活性虽不低,稳定性却较差,这种催化剂能吸附CO,IR谱图上仅在1919cm~(-1)处有CO桥式吸附态的伸缩振动。表明除络合钯原子外,还有聚集的钯金属存在。FT-IR尚表明,PVP在Al_2O_3上可能并非单纯的物理吸附。电镜结果表明,PVP在Al_2O_3上呈30—70(?)的微球状,(PdCl_2-PVP)/Al)_2O_3上的(PdCl_2-PVP)亦呈微球状,与前者无明显区别,这种催化剂中其活性中心是络合钯原子。 |
| 英文摘要: |
| The catalyst prepared by coordinating PdCl2 with polyvinylpyrrolidone and then supporting on Al2O3 exhibited good activity, selectivity and stability in the hydrogenation of olefines. This type of catalyst was characterized by X- ray photoelectron spectroscopy, electron microscopy and FI- IR spectroscopy. Experimental data showed that the valence state of Pd was between 0 to 2 and the weak 486 cm-1 band in the IR spectra of PdCl2-PVP suggested the existence of Pd-N coordination bond. The catalyst with low Pd content (0. 2 wt%) exhibited good activity and stability. It did not adsorb any CO. Its active species is proposed to be the coordinated Pd atom. In the case of high Pd content (0. 7 wt% or more), though it kept high initial activity, but the stability was poor. By using CO as probe there was only a 1919 cm-1 band corresponding to the stretching vibration of bridge type adsorbed CO in the IR spectra. It revealed that besides the coordinated Pd atom, some Pd aggregated to very fine particles as well. Electron micrographs showed that PVP stayed on AL2O3as round particles(30-70 A ) and PdCl2-PVP deposited in an analogous state on the Al2O3 surface. |
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