Homologation Of Methanol Research Articles

Methanol homologation by cobalt-phosphine-iodine catalyst systems

Despite numerous research efforts, the mechanism of methanol homologation and especially the role of iodine promoters remain unclear. In an approach to improve the understanding of this reaction, the basic properties of cobalt-iodine-phosphine catalyst systems have been studied. In addition, well-defined cobalt complexes and clusters were used as catalysts, and experiments with labelled reagents have been carried out. Based on these data a reaction mechanism via oxidative addition of methyl iodide to a cobalt(I) center is proposed.

The reductive carbonylation of methanol with homogeneous iron-cobalt catalysts

Salts of the FeCo 3(CO) − 12 anion promoted with methyl iodide have proven to be effective catalysts for the methanol homologation reaction. These catalysts are similar but superior to other CoI homologation catalysts and it is suspected that many similar intermediates are involved. Infrated evidence has shown that the FeCo 3 cluster does not remain intact during the reaction, but the nature of the active catalyst species is not known. Monitoring the product composition at short reaction times has shown that acetaldehyde, which is formed simultaneously with a small amount of methyl acetate, is the primary homologation product. By varying many of the reaction parameters, relatively high yields of acetaldehyde are obtained. Ethanol can be produced in reasonable yields under more vigorous conditions than those required for acetaldehyde, but under such conditions side reactions become increasingly important.

ChemInform Abstract: HOMOLOGATION OF METHANOL CATALYZED BY MIXED TRANSITION METAL CLUSTERS CONTAINING COBALT

AbstractDer aus RuCl3 mit Na[Co(CO)4] leicht zugängliche Clusterkomplex (III) wird nach Austausch des Kations als Katalysator bei der Homologisierung von Methanol (IV) mit CO und H2 zu Ethanol (V) eingesetzt.

THE HOMOLOGATION OF METHANOL. THE MODIFICATION OF COBALT CATALYST BY DIPHOSPHINES

Abstract Cobalt iodide modified by α,ω-bis(diphenylphosphino)alkane (PCnP; n=1–6) efficiently catalyzes the homologation of methanol to ethanol. The ethanol selectivity as high as 89% was achieved by using PC6P as the ligand.

HOMOLOGATION OF METHANOL CATALYZED BY MIXED TRANSITION METAL CLUSTERS CONTAINING COBALT

Abstract Syntheses of mixed transition metal clusters containing cobalt and their catalytic activities for homologation of methanol were investigated. The reaction of RuCl3 with Na[Co(CO)4] gave a reddish brown complex Na [RuCo3(CO)12]. The cluster easily underwent a cation exchange to give the Cs+ and [Et4N]+ salts. These clusters showed a remarkable catalytic activity for homologation of methanol. The selectivity of ethanol was increased up to 51% in ca. 40% conversion in case of [Et4N]+ salt. Catalytic activities of some other mixed metal clusters were also examined.

Chimie organometallique XIV. Homologation du methanol par des catalyseurs homogenes derives de cobalt

Selectivity for ethanol in the cobalt-catalysed methanol homologation reaction is increased by addition of borates and decreased by addition of hard cations. The influence of borates is assigned to an increase in carbenoid character of the intermediate acylcobalt, which should make hydrogenolysis easier.

Methanol Homologation Reaction Catalyzed by Cobalt Carbonyl

Methanol Homologation Reaction Catalyzed by Cobalt Carbonyl