III International Conference

PP-II-124MODIFYING INFLUENCE OF WHITE PHOSPHORUS AND PHOSPHINE (PH 3 )IN THE PRODUCTION OF NANOSCALE PALLADIUM HYDROGENATIONCATALYSTSSkripov N.I., Belykh L.B., Schmidt F.K.Irkutsk State University, Irkutsk, RussiaE-mail: fkschmidt@chem.isu.ruThe formation, nature and properties of palladium nanoscale hydrogenation catalystsmodified by white phosphorus or phosphine have been studied. It has been shown that whitephosphorus and phosphine exceed significantly in magnitude of promoting effect nanoscalepalladium hydrogenation catalysts with organic phosphines studied earlier. One of the reasonsfor promoting effect of phosphorus and phosphine at low ratio P/Pd compared with Pd-blackis a dispersity increase of the catalyst consisting of palladium clusters Pd(0) and palladiumphosphides of different composition.In this paper, data on the formation, nature and properties of nanoscale hydrogenationcatalysts based on palladium bis-acetylacetonate, white phosphorus and phosphine formed undermolecular hydrogen are presented. It has first been shown that the usage of white phosphorus orphosphine (PH 3 ) as the modifiers at the stage of synthesis allows one to obtain highly effectivepalladium nanoscale hydrogenation catalysts whose specific activity exceeds that of nanoscalecatalysts based on palladium complexes with organic phosphines [1]. An influence of differentparameters on the composition and properties of the catalysts has been studied. It has been shownthat the size, nature and therefore catalytic properties of formed nanoparticles depend on the ratioP/Pd. Independently of the promoter nature (P 4 , PH 3 , PH 2 Ph [2]) the most effective hydrogenationcatalyst is formed at the ratio P/Pd = 0,3. That catalyst consists mostly of the nanoparticles in8-10 nm containing palladium phosphides of different composition (Pd 6 P, Pd 4,8 P, Pd 5 P 2 ) andpalladium in reduced state the share of which attains 30%. One of the reasons for promoting effectof phosphorus and phosphine is a dispersity increase in comparison with Pd-black formed underthe similar conditions. Using the complex of the physical-chemical researches of the catalyticsystems (NMR, IR-, UV-spectroscopy, X-ray diffraction, TEM) the model of active catalyst hasbeen suggested. The general trends and distinctions in the formation and nature of thenanoparticles of palladium hydrogenation catalysts obtained in the presence of differentcontaining phosphorus compounds have been established.References1. Schmidt F.K., Belykh L.B.,Goremyka T.V. // Kinet. Katal. – 2003. – Т. 44, N 5. – C. 683-691.2. Belykh L.B., Goremyka T.V., Belonogova L.N., Schmidt F.K. // J. Mol. Catal. – 2005. – V 231,N 1-2. – P. 53-59.392