Process for the recovery of cobalt catalysts from the products formed during the oxo reaction

摘要

Cobalt is recovered from the degassed liquid product of a cobalt-catalysed oxo reaction by heating the product at a temperature of 100-190 DEG F. and at an absolute pressure of 10-25 p.s.i. with steam, separating from the resulting mixture an aqueous phase substantially free of cobalt, and removing cobalt from the remainder of the mixture. In one embodiment of the invention the steam is provided at atmospheric pressure or slightly above, and the mixture separates into three phases-a clear top organic phase, a clear aqueous phase and at the interface between the layers a thick black suspension containing the cobalt and referred to as the cobalt "interfacial rag". The liquid layers can be separated leaving the interfacial rag which can be recovered as a cobalt soap and recycled to the oxo reactor. In another modification the cobalt is converted into a form which passes into the organic layer by passing an oxygen-containing gas into the mixture either at the same time as or subsequently to passing in the steam. The organic layer is then separated and distilled to give a bottoms fraction containing cobalt which can be recycled to the oxo reactor. The oxygen-containing gas may be commercial oxygen, air, air diluted with inert gas. The interfacial rag may be converted to a form suitable for use as catalyst in the oxo reaction by treating it with sulphuric acid to form the sulphate, treating the sulphate with an alkali metal hydroxide and then adding an acid such as oleic acid, linoleic acid, stearic acid or tall oil acid. Alternatively the interfacial rag may be treated direct with the organic acid while passing oxygen into the mixture. Specification 682,177 is referred to.