Patent GB-811850-A (GB)
Title: Ketone synthesis
IPC: C07C45/00
Filed: 1955-08-08
Abstract: Ketones containing 2n + 1 carbon atoms are prepared from olefinically unsaturated compounds containing n carbon atoms by a process comprising reacting the olefinic compound with carbon monoxide and a hydrocarbon that acts as a hydrogen donor in the absence of a dehydrogenation catalyst, the reaction being carried out in the absence of extraneously added molecular hydrogen and in the presence of a cobalt containing carbonylation catalyst under a pressure of from 1500 to 5000 p.s.i.g. and at a temperature that is at least 250 DEG  F. but is not sufficiently high to decompose cobalt carbonyl or, in conjunction with the amount of hydrogen donor used, to produce quantities of molecular hydrogen from the donor sufficient to suppress formation of the ketone.  In a modification, the olefinic compound is reacted with carbon monoxide and a mono- or poly-C1-5 alkyl-benzene in the absence of extraneously added molecular hydrogen and in the presence of a cobalt-containing carbonylation catalyst and a small amount (0.5 to 5 per cent by weight) of a heterogenous dehydrogenation catalyst under a pressure of from 1500 to 5000 p.s.i.g. and at a temperature that is at least 250 DEG  F. but is not sufficiently high to decompose cobalt carbonyl or, in conjunction with the amounts of aromatic hydrocarbon and dehydrogenation catalyst used, to produce quantities of molecular hydrogen from the aromatic hydrocarbon that are sufficient to suppress formation of the ketone. Specified olefinic compounds are ethylene, propylene, butylenes, amylenes and C7-12 straight or branch-chained olefines.  Suitable hydrocarbons which are direct hydrogen donors are alkylated cycloparaffins, iso paraffins and certain hydrocarbon-substituted multiple ring or partially hydrogenated multiple-ring aromatic hydrocarbons, such as 1 : 2 : 3 : 4-tetrahydronaphthalene, hydrogenated thermal tar, methyl cyclohexane and isopentane.  The isoparaffins and alkylated cyclo paraffins, however, are preferably used in conjunction with the heterogeneous dehydrogenation catalyst mentioned above.  Specified C1-5 alkyl benzenes are toluene, xylenes and ethyl benzene. Suitable dehydrogenation catalysts are nickel, copper and chromia.  The cobalt catalyst may be cobalt metal or its carbonyl, oleate, naphthenate or other salt, preferably soluble in the olefin feed; oil-insoluble forms of cobalt, however, may also be used such as aqueous salt solutions e.g. of cobalt acetate or a slurry of the oxide.  The olefinic reagent may be dissolved in a solvent which may be inert or may comprise at least in part the hydrocarbon hydrogen donor or its dehydrogenated product formed in the reaction, such as hexane, heptane, cyclohexane, toluene, benzene, xylenes and polar compounds such as ethers.  Suitable apparatus is described wherein an olefinic feed, carbon monoxide, cobalt catalyst and hydrocarbon hydrogen donor are passed into a reactor under preferred conditions of 300-400 DEG  F., 3000-5000 p.s.i.g., an olefin feed rate of about 0.1 to 10 v/v/hour, a carbon monoxide feed rate of 1000-4000 cu. ft./barrel of olefin, a ratio of 1 : 1 to 5 : 1 mols. of hydrogen donor per mol. of olefine and a residence time of 0.1 to 10 hours.  Liquid product is separated from unreacted gases and is decobalted and then distilled to recover the ketone formed, any byproduct aldehyde, the inert solvent, if used, and a mixture of unchanged and dehydrogenated hydrocarbon hydrogen donor which mixture is recycled to the reactor preferably after hydrogenation to regenerate the hydrogen donor.  Data is tabulated for a number of batch-experiments wherein (1) ethylene, diluted or not with hexane is reacted with carbon monoxide at 150-200 DEG  C. under 3500-3700 p.s.i.g. pressure in the presence of cobalt oleate using, as hydrogen donor, either tetrahydro naphthalene alone or methyl cyclohexane with a nickel-onkieselguhr or copper dehydrogenation catalyst yielding diethyl ketone, a C3 aldehyde and a C6 unsaturated aldehyde; (3) propylene is similarly reacted with carbon monoxide and tetrahydronaphthalene yielding 4-heptanone, butyraldehyde and a C8 unsaturated aldehyde.  Comparative experiments are also described wherein (a) ethylene is reacted substantially as in (1) at 200 DEG C. using a larger amount of tetrahydronaphthalene whereby are formed a C3 aldehyde and saturated and unsaturated C6 aldehydes but no ketone and (6) wherein ethylene diluted with hexane is reacted with carbon monoxide and hydrogen at 175 DEG  C. under 3500 p.s.i.g. pressure using a cobalt oleate catalyst with formation only of a C6 unsaturated aldehyde and a minor amount of a C3 aldehyde.