GB659701A - A process for decomposing cobalt compounds in formylation products and apparatus therefor - Google Patents

Abstract

Cobalt compounds contained in products obtained by reaction of olefinic compounds with CO and H2 in presence of cobalt catalysts are decomposed by raising said products to the temperature required for the decomposition by mixing with a reaction product heated above the decomposition temperature, in which product the cobalt compounds have already been decomposed. The product to be decobaltized may be preheated, for example to 80-100 DEG C., if desired in presence of CO or a gas containing it, before mixing with the decobaltized product at a temperature of 200-350 DEG C. The latter may be heated in presence of hydrogen at above 10 atm. A recycled portion of the products obtained in the decomposition may be used for the heating. The ratio of recycled product to material to be decobaltized is generally 1-5 : 1, dependent on the temperature. The cobalt liberated may be absorbed by a carrier, for example that recycled with the decobaltized product of a reaction using a suspended cobalt catalyst on a carrier. The decomposition is effected in the presence of hydrogen if cobalt in an active form for hydrogenation is required. The hydrogenated product comprising alcohols or the high boiling fraction thereof after distillation of alcohols may be used as the heating medium. An apparatus for decobaltizing comprises two concentric vessels, the inner one having a conical base with an inlet at the apex to which product to be decobaltized and hydrogen are fed. The product is forced up through the inner vessel, flows over the top and down through the annular space where it is heated, and is then entrained by the fresh feed. In examples: (1) C6-C8 alkenes are converted to a product containing aldehydes and alcohols using a suspended cobalt - kieselguhr catalyst. The product is fed at 20 DEG C., together with decobaltized product at 300 DEG C. and hydrogen, to the base of a tower at a pressure of 50 atm.; (2) an aldehydic product is preheated to 100 DEG C. and mixed with decobaltized product at 200 DEG C. to give a final temperature of 180 DEG C. The decobaltized product, after separating from gas, is in part recycled, and the remainder hydrogenated to alcohols.