Phosphorus-based catalysts characterizing

IR Data Characterizing Selected Phosphorus-Based Catalysts after Drying and Calcination... 

Following Section 11. J, which reported some characteristic vibrational and NMR data representing phosphorus-based reference compounds (Tables VI-Vlll), it is interesting to propose similar compilations concerning phosphorus-containing alumina catalysts in the dried and calcined forms. These vibrational and NMR data (Tables IX-XII) are more informative in characterizing hydrotreating catalysts than are XRD data because the catalysts are amorphous. 

More remarkably, structurally well-characterized Phen-containing transition metal complexes have been prepared and further applied in challenging organic transformations. Thus, cationic palladium complexes of t)fpe Pd(phen)2X2 (where X = CF3SO3, PFs, BF4) are very stable and found fairly active in combination with either benzoic acids or phosphorus acids as cocatalysts in the conversion of nitroarenes to the corresponding carbamate derivatives. Extensive studies have evidenced the key role of the nature of counteranion X of such Phen-based catalysts in the reaction outcome and even metaUacycles of type A have been isolated and identified as active intermediates in the reductive carbonyla-tion of nitrobenzene (eq l). ... 

Theories and principles of the characterization techniques are not described here. For consistenc), all the catatysts described in this review are referred to with the same nomenclature, although a different nomenclature is sometimes used in the cited publications. Each catalyst component (element) separated by the symbol indicates the sequence of its introduction into the catalyst formulation from right to left. Those separated by the symbol 7 between right and left belong to the support material and the elements on the support, respectively. For example, NiMo-P/Al refers to a catalyst prepared such that the phosphorus-containing precursor is loaded on the alumina support first, followed by nickel and molybdenum, which are introduced simultaneously. CoMo/Al — P refers to a catalyst in which cobalt and molybdenum are introduced simultaneously onto an alumina support doped with phosphorus-containing species. Each element may represent its oxide or sulfide forms. In all cases, A1 refers to the alumina-based support or to its hydroxide precursor. 

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