GB824331A - Preparation of metallic hydrocarbonyls - Google Patents

Abstract

Cobalt hydrocarbonyl is produced by reacting an organic or inorganic cobalt salt, e.g. cobalt formate or acetate, with a gaseous mixture comprising hydrogen and carbon monoxide at a temperature of 90-180 DEG C. in the presence of an organic solvent. The solvent must be insoluble in water and inert under the reaction conditions. The solvent may be a primary aliphatic alcohol or aldehyde containing at least 4 carbon atoms, e.g. iso-octyl alcohol or aldehyde, or a crude mixture obtained by decobalting oxo products or by hydrogenation of the product of a hydroformylation reaction. The reaction may take place in the presence or absence of water. In the former case an aqueous solution of the (metal) hydrocarbonyl is produced directly, while in the latter case the hydrocarbonyl may be extracted from the organic solvent by the subsequent addition of water. An aqueous solution of a cobalt salt containing 2-5 wt. % of cobalt and 10-100% of solvent based on the aqueous solution may be employed. The reaction may be carried out at a pressure of 1000-4000 p.s.i.g., and a contact time of 0.5-6 hours. The hydrogen-carbon monoxide mixture may be employed in a 10-100 fold stoichiometric excess with respect to cobalt. The hydrogencarbon monoxide ratio may be 0.5-4 to 1, preferably 1 to 1. According to the embodiment illustrated (Figure not shown), an aqueous solution of a cobalt salt is passed downwards through a tower in counter-current to synthesis gas and recycled solvent. The reaction may be allowed to proceed to a limited extent such that the unreacted cobalt salt is at least stoichiometrically equivalent to the hydrocarbonyl produced, so as to produce a salt of the hydrocarbonyl. Cobalt carbonyl may be produced by treating an aqueous solution of the hydrocarbonyl under acidic conditions with air.