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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。
PdCl2-PVP / Al_2O_3], which is anchored on polyvinylpyrrolidone and then further supported on Al_2O_3, is an active, highly selective and stable olefin, diolefin and poly Olefin Hydrogenation Catalyst. In this paper, the hydrogenation reaction, the use of XPS, FT-IR, electron microscopy and CO-probe FT-IR, the catalyst was investigated. Experiments show that in this catalyst, palladium valence is between 0-2. Infrared spectrum at 486cm -1 has a weak small peak, indicating the presence of Pd-N coordination bond. When the content of palladium is low (0.2wt%), the catalyst has good stability and does not adsorb CO. The active center is a complex palladium atom. When the content of palladium is higher (0.7wt%), the initial activity of the catalyst is not low, but the stability On the contrary, this catalyst can adsorb the stretching vibration of the CO and IR spectra with the CO bridging adsorption state at 1919cm -1. Show that in addition to complexing palladium atoms, but also the presence of aggregated palladium metal. FT-IR still shows that PVP may not be purely physical adsorption on Al 2 O 3. Electron microscopy results showed that the PVP was (PdCl_2-PVP) / (AlCl 2 -PVP) microspheres in the shape of 30-70 (?) On Al 2 O 3, and had no obvious difference from the former Its active center is a complex palladium atom.