Patent GB-784317-A (GB)
Title: Improvements in catalyst decomposition in carbonylation of olefins
IPC: C07C27/22
Filed: 1953-04-17
Abstract: A carbonylation process comprises reacting, at an elevated temperature and pressure, an olefinic feed with CO and H2 in the presence of a cobalt carbonylation catalyst to form a crude aldehyde product containing dissolved cobalt carbonyl, decobalting the crude aldehyde by treatment with liquid water, heat being supplied to the mixture of aldehyde and water during the decobalting treatment at least in part through a surface of a heat-exchanger, separating substantially cobalt-free aldehyde and water containing dissolved cobalt formate from the product of the decobalting treatment, and reusing at least a portion of the separated water containing cobalt formate in the decobalting of further aldehyde product containing dissolved cobalt carbonyl. The formate ions are derived from formic acid obtained by the hydrolysis of its esters produced as by-products in the process. 2-50 per cent of water may be added, based on the volume of aldehyde product at temperatures of 250-500 DEG , preferably 250-350 DEG  F., and pressures of 50-175, preferably 100-175 p.s.i.g.  Preferably decobalting is effected by passing the aldehyde product through one or more vessels heated with steam coils whilst water is simultaneously injected into the vessels, the aqueous mixture residing in the vessel, e.g. for 0.5-4 hours, until the catalyst is decomposed.  Advantageously water is maintained in the heating vessel as a continuous phase, the vessel best being completely filled with water.  The aqueous mixture obtained after catalyst decomposition may be passed to a vertical conical settling vessel and allowed to stratify.  The upper layer consists of aldehyde product which may be withdrawn and hydrogenated to alcohols.  The bottom layer consists of the cobalt slurry which is withdrawn for cobalt recovery and reuse as catalyst in the process.  Cobalt may be recovered in the form of the metal or its formate or basic formate. A clear aqueous stream containing cobalt formate is withdrawn at an intermediate point at least a portion of which is recycled to the heater.  If plugging of slurry lines occurs the full water load may be removed from the bottom of the cone and at least some of the aqueous stream returned to the heater after removal of solids by settling. After continuous recycling the quantity of cobalt in the aqueous stream may build up so that the stream may be used as carbonylation catalyst.  In a modification, decobalting is effected by passing a mixture of crude aldehyde product and separated cobalt formate containing hot water into a first zone containing no auxiliary heating means, the hot water being in an amount such as to raise the temperature of the mixture to above 190 DEG  F., so that substantial but not complete decobalting occurs and thereafter passing the mixture to a second zone, maintained at a higher temperature than the first zone by the supply of heat thereto through the surface of a heat exchanger, wherein decobalting is substantially completed.  A diagram is provided of suitable apparatus for the process.  Specification 717,446 is referred to.  Reference has been directed by the Comptroller to Specification 660,737.