GB702950A - Improvements in or relating to oxo alcohol synthesis - Google Patents

Abstract

Aldehydes containing dissolved cobalt obtained by the Oxo synthesis are intimately contacted in a decobalting zone with a dilute aqueous solution of an organic acid whose cobalt salt is water-soluble and oil-insoluble to form a solution of a cobalt salt which is separated. It may be recycled directly to the synthesis zone to provide catalyst and cooling, neutralized to form the hydroxide which is recycled in suspension in an organic liquid, e.g. aldehyde product or olefin, or heated with a higher organic acid to form an oil-soluble salt. Suitable acids for the decobalting are acetic, formic or oxalic. The temperature is about 150-200 DEG F. The Oxo synthesis is preferably effected at 200-450 DEG F. and 2500-3500 p.s.i.g. with a cobalt soap such as naphthenate or oleate or an aqueous solution of an organic cobalt salt as catalyst. The liquid products may be in part recycled, and the remainder is mixed with sufficient acid to combine with all the cobalt and water to dissolve the salt formed. 10 per cent. of a 5 per cent. aqueous acetic acid is suitable. A mixing time of 30-120 mins. is usual. After stratifying, the aldehyde layer may be washed with hot, then with cold water. The aqueous layer may be recycled to the reactor or the cobalt first converted as indicated. The water added to the reactor should not be much above 3-5 per cent. of the olefin. The process may be applied to aldehydes already subjected to the usual thermal decobalting. Examples employ formic or acetic acid for treating C8 aldehydes. Specification 679,664 is referred to.