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Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, XI [1]. Ether-Phosphan-Cobalt-Komplexe in der katalytischen Methanolhydrocarbonylierung zu Acetaldehyd / Novel Basic Ligands for the H om ogeneous Catalytic Methanol Carbonylation, XI [1]. Ether Phosphane Cobalt Complexes in the Catalytic Hydrocarbonylation of Methanol to Acetaldehyde

Lindner, Ekkehard, Schober, Uwe, Glaser, Erhard, Norz, Hubert, Wegner, Peter
Zeitschrift für Naturforschung 2014 v.42 no.12 pp. 1527-1536
acetaldehyde, bromine, chemical bonding, cobalt, ligands, methanol, models, sodium, trapping
PhP(CH₂C₄H₇O₂)₂ (1) and [-CH₂(Ph)P~D]₂ (3a-c) [D = CH₂C₄H₇0₂ (a), CH₂C₄H₇O (b). CH₂CH₂OCH₃ (c)] are obtained by reaction of Li₂PPh and Na(Ph)P~D with ClCH₂C₄H₇O₂ and C1CH₂CH₂Cl, respectively. 1 and 3a, b give rise to high selectivities and conversions in the cobalt catalyzed hydrocarbonylation of methanol to acetaldehyde. Model complexes of cobalt which are of importance in the catalytic cycle are synthesized. Complexes of the type X₂Co(Ph₂P~D)₂ (6az, 6bx-bz, 6cx-cz), especially those with X = I, obtained from CoX₂ [X = Cl (x), Br (y), I (z)] and the ether phosphanes Ph₂P~D (5a-c), are regarded as precursors of the catalytically active species. With K[HB(sec-C₄H₉)₃] they are reduced to the cobalt(I) complexes XCo(Ph₂P~D)(Ph₂P~D) (7az, 7bx-bz, 7cx-cz). Trapping reactions with CO, PPh₃ or 5b, c lead to the compounds XCo(CO)₂(Ph₂P~D)₂ (8az, 8bx-bz, 8cx-cz), XCoPPh₃(Ph₂P~D)₂ (9bx-bz). and XCo(Ph₂P~D)₃ (10bz, cz), respectively, with cleavage of a Co-O bond. The reduction of X₂Co(PPh₃)₂ (11x, z) with K[HB(sec-C₄H₉)₃] represents a simple method for the preparation of the complexes XCo(CO)₂(PPh₃)₂ (13x, z) which are formed from the intermediates XCo(PPh₃)₂ · THF (12x, z) in the presence of CO.