GB684673A - Improvements in and relating to carbonyl-containing compounds - Google Patents

Abstract

Oxygen - containing organic compounds, especially aldehydes, are made when an olefine is reacted in the liquid phase in countercurren-with CO and H2 in the presence of a carbonylation catalyst at elevated temperature and pressure in a reactor so that the olefine is introduced above the point of entry of the carbonylaing gas which is introduced at an intermediate point in the reactor and a gas rich in hydrogen is introduced at a point below the point of introduction of the carbonylating gas. The olefine may be added dissolved in an inert diluent, e.g. saturated butene trimer, 3,5,5 - trimethyl hexanol, dinonyl ether and di-isobutylene when olefines containing up to 5 carbon atoms are being treated. Preferably the inert medium is added above the point of entry of the olefine. Preferably the reactor is cooled by indirect cooling coils and the carbonylating gas may be used for cooling. Preferably the reactor is lined with a metal not readily attacked by CO, e.g. Cu, Ag or stainless steel. Liquid products are removed at the bottom of the reactor. The gas containing hydrogen is used as a stripper so that a suitable arrangement comprises in descending order a carbonylation zone, a stripping or carbonyl decomposition zone and a filtering zone. The magnetic separator of Specification 670,423 may be used. The decomposition zone is desirably of such dimensions as will give a residual CO content in the product of preferably not more than 1 litre at N.T.P. per kilogram of liquid product and when unpacked narrow diameter reactors are used a depth of at least 10 feet is preferably required. When the catalyst is cobalt a depth of at least 4 feet is sufficient to reduce the dissolved cobalt of the liquid to about 0.002 per cent by weight. Preferably the hydrogen is pure hydrogen and free from oxygen. The product is worked up for aldehydes, e.g. by the flash distillation of Specification 655,976, [Group III], and hydrogenated to alcohols, e.g. at 250 atmos. and with a copper chromite catalyst in a separate stage. Preferably the molar ratio of H2 : CO is 1 : 1 although a ratio of 4 : 1 is also specified, but if ordinary steel equipment is used this ratio should be not less than 2 : 1 and preferably about 3 : 1. Excess gases may be recycled. The preferred catalyst is cobalt, particularly as the carbonyl, and it may be injected as such or formed from a metal salt dissolved in the liquid reactant or medium, or from the metal on a support by reaction with CO. 0.1 to 1.0 per cent is a suitable concentration of cobalt dissolved in the feed. Reaction conditions specified are 200-300 atmos. gauge and 100-180 DEG C. for carbonylation and similar temperatures for p decomposition. Preferably the pressure is 250 atmos. when the volume ratio gas: olefine is preferably 1000 : 1 to 3000 : 1 and the temperature of the decomposition zone is about 150 DEG to 170 DEG C. Cyclohexene is a specified aldehyde. In an example, di-isobutene is carbonylated and the product hydrogenated to 3,5,5-trimethyl hexanol.