Production of alcohols by oxo process

摘要

Alcohols are produced by reacting a synthesis gas containing hydrogen and carbon monoxide with an olefine in the presence of a metallic hydroformylation catalyst to form an aldehydic product contaminated with the catalyst, removing at least a substantial proportion of the catalyst from the aldehydic product in a demetalling zone, contacting the aldehydic product from the demetalling zone with a metal from Group VIII of the Periodic Table or the oxide of such a metal in a contact zone at temperatures of 143-204 DEG C. and elevated pressure and catalytically hydrogenating the resulting aldehydic product. The preferred contact material is nickel or its oxide and preferably the product from the demetalling zone is contacted with it in the presence of hydrogen and of water or steam. The "Group VIII metals" referred to are iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum. To insure continuous operation of the process two contact chambers in parallel are used so that when the contact material in the one chamber becomes deactivated the demetalled aldehydic product may be diverted to the other while the deactivated material is replaced or reactivated. Preferred catalysts for the hydroformylation step are cobalt octanoate and cobalt naphthenate. In the preferred method of carrying out the process, the demetalling chamber is packed with pumice and is maintained at a temperature of 99 DEG to 204 DEG C. and a pressure of 1.75 to 35 kgs. per sq. cm. The Group VIII metal contact material used in the contact chamber may be deposited on kieselguhr. The hydrogenation reactor is operated under adiabatic conditions and is packed with a suitable hydrogenation catalyst, preferably a nickel catalyst, similar to that used in the contact chamber. It is maintained at a pressure of 3.5 to 350 kgs. per sq. cm. and a maximum temperature in the range 193 DEG to 204 DEG C. In an example a decobalted hydroformylation product containing iso-octyl aldehyde and obtained by the hydroformylation of heptene is passed into a contact chamber containing nickel oxide on kieselguhr, along with water and hydrogen; the product is then passed into a hydrogenation reactor containing a similar nickel catalyst; the product from the hydrogenation zone contains iso-octyl alcohol.ALSO:In a process for the production of alcohol by the oxo process the products from the hydroformylation step are passed first to a demetalling zone to remove at least a substantial proportion of contaminating hydroformylation catalyst from the aldehydic product and then to a contact zone containing a catalyst consisting of a metal from Group VIII of the Periodic System, or an oxide of such a metal, at temperatures in the range 143 DEG to 204 DEG C. before they are submitted to catalytic hydrogenation. The catalyst in the contact zone becomes deactivated by contamination with, for example, sulphur, sulphur-containing compounds and free metals resulting from decomposition of metal carbonyls. To regenerate the spent catalyst it is preferably initially purged with hot hydrogen gas and then flushed with steam. It is then heated with inert gas such as nitrogen or carbon dioxide and air is then introduced at a temperature of 475 DEG to 550 DEG C. After the impurities have been burnt off the catalyst may be cooled to 150-205 DEG C. and may be used without reduction. Alternatively, the catalyst is cooled a little and reduced with hydrogen to an extent of 20-80 per cent. Before re-using the catalyst it is advisable, regardless of the method of deactivation to steam it with superheated steam. The preferred catalyst is partially reduced nickel oxide which may be mounted on kieselguhr. Other metals which may be used as catalyst are iron, cobalt, ruthenium, rhodium, palladium, osmium, iridium and platinum.