Neuartige basische Liganden für die homogenkatalvtische Homologisierung von Methanol zu Ethanol, III [1]. Der Einfluß neuartiger P–N-Liganden auf die Selektivität und den Umsatz bei der Ethanolsynthese aus Methanol / Novel Basic Ligands for the Homogeneous Catalytic Homologation of Methanol to Ethanol, III [1]. The Impact of Novel P-N-Ligands on the Selectivity and Conversion for the Synthesis of Ethanol from Methanol

Abstract

The N -P-N-ligands RP(XC₅H₄N)₂ (1b′, c′, b″, c″) [X = O: R = t-Bu (b′), Me (c′); X = NH: R = t-Bu (b″), Me (c″)] are characterized by their different complex chemical behaviour towards group VI metal carbonyl derivatives. By reaction of 1b′, c′, b″, c″ with (CH₃CN)₃M(CO)₃ the complexes (OC)₃M[RP(XC₅H₄N)₂] (2b′, c′, 3b″) and (OC)₄W|[CH₃P(NHC₅H₄N)₂] (3c″) [M = Mo (2).,W(3)] are formed in which the ligands are tridentate and bidentate, respectively. This difference can be explained with the existence of hydrogen bridge linkages between NH and pyridyl groups in 3c″. Homologation experiments of methanol with 1, CoOAc_: and I₂ as an activator show high conversions (85%) with about 40% of ethanol selectivity. The lowest selectivities are found with 1c″.