US 7,910,782 B2Granted

Cobalt recovery from cobalt catalysed hydroformylation reactions

AssigneeExxonMobil Chemical Patents Inc.

InventorsEddy T. A. Van Driessche, Arie Van Vliet, Raphael Frans Caers, Hubertus Joseph Beckers, Ronald Dean Garton, Bertrand Raymond Da Cruz, Michel J. P. Lepagnol, Edwin Kooke

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Abstract

In a hydroformylation reaction, the circulation and recovery of cobalt carbonyl in a cobalt catalyst cycle using carbonylate as an intermediate and acidification thereof, is improved by supplying an aqueous sulfuric acid solution containing less than 16% wt of sulfuric acid to the carbonylate to control sulfuric acid concentration in the carbonylate/acid mixture, before accounting for any acid consuming reaction, to a value of from 2% to 10% by weight. Single step and multistage liquid/liquid extraction techniques as well as vapor/liquid extraction techniques followed by the absorption of cobalt from the vapor in an organic liquid both benefit from this improvement.

Claims14

Dependent claims

A process for the recovery of cobalt from the product of a continuous cobalt catalysed hydroformylation reaction, which recovery process comprises the steps of:

(i) by a treatment of the hydroformylation product with dilute base forming a carbonylate, comprising a water soluble salt of a carbonyl of the cobalt hydroformylation catalyst,
(ii) acidifying the carbonylate by combining said carbonylate with an aqueous sulfuric acid solution to form a carbonylate/acid mixture, and
(iii) recovering hydrocobalt carbonyl from the acidified carbonylate, thereby producing a dilute acid effluent,
wherein the aqueous sulfuric acid solution used for acidifying the carbonylate has a sulfuric acid concentration of less than 16 wt % and the acidification step is performed to provide a sulfuric acid concentration in the carbonylate/acid mixture, before any sulfuric acid consuming reaction, of from 2% to 10% by weight, based on the weight of the mixture.

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Dependencies are inferred from the claim text.