3,644,529 United States Patent Office Patented Feb. 22, 1972 2 formylation reaction product to a decobalting operation 3,644,529 to remove cobalt carbonyl therefrom. This has generally OXO PROCESS involved subjecting the hydroformylation reaction prod Edmond R. Tucci, Pittsburgh, and Helen . Thayer and luct to temperature and pressure conditions favoring the John V. Ward, Oakmont, Pa., assignors to Gulf Re decomposition of cobalt carbonyi to elemental cobalt and search & Development Company, Pittsburgh, Pa. carbon monoxide. Elemental cobalt is difficult to remove No Drawing. Filed Aug. 23, 1966, Ser. No. 574,316 from the hydroformylation reaction product, and it has it, C, CO7c 45/10 a tendency to plug the lines leading to and from the de U.S. C. 260-604 HF 14 Claims cobalter and for some to find its way into the hydrogena tion reactor. The removal of such cobalt adds significantly ABSTRACT OF THE DISCLOSURE to the overall cost of the hydroformylation reaction. Co balt so obtained, in addition, has to be discarded or, by a An Oxo process wherein an olefin is reacted with hydro tedious procedure may, perhaps, be converted back to the gen and carbon monoxide in the presence of a cobalt original cobalt salt or cobalt carbonyl for use in the hydro carbonyl and a dioxaphosphacyclohexane, preferably in formylation reaction zone. the presence of a trialkyl amine. We have found, however, that the above discussion can be avoided by employing in the hydroformylation re action Zone a cobalt catalyst such as defined above and a This invention relates to an Oxo process or hydro specific dioxaphosphacyclohexane selected from the group formylation reaction, wherein hydrogen and carbon mon consisting of 2,4,6-tris (alkyl)-1,3-dioxa-5-phosphacyclo oxide are added to an olefinic compound in the presence 20 of a catalyst to obtain a mixture predominating in an hexane and 2,4,6-tris(aryl)-1,3-dioxa-5-phosphacyclohex aldehyde having one more carbon than said olefinic com ane having the following structural formula: pound. The catalyst generally employed for the hydroformyl ation reaction is a cobalt salt of a higher molecular 25 P weight fatty acid, such as octanoic, steric, oleic, palmitic, naphthenic, etc. acids. Inorganic salts, such as Rs - it i-Fi. cobalt carbonate, can also be used. Most of these salts O Q are soluble in most of the olefinic feeds supplied to the Ng/ hydroformylation reaction zone, but when they are not, 30 they can be supplied in an inert, liquid hydrocarbon in i. which they are soluble, such as benzene, Xylene, naphtha, wherein R1,R2 and Ra, the same or different, are straight heptane, decane, etc. Although the catalyst is supplied in chain or branched alkyl substituents having from one to the form of a cobalt salt to the hydroformylation reaction 16 carbon atoms, preferably one to 10 carbon atoms, or zone, under the conditions existing therein the salt reacts aryl substituents having from 6 to 16 carbon atoms, pref with carbon monoxide, preferably in the presence of hy erably from 6 to 10 carbon atoms and X is selected from drogen, to form a cobalt carbonyl, that is, one or more the group consisting of hydrogen, fluorine, chlorine, bro of the following: cobalt hydrocarbonyl, HCo(CO)4; di mine, iodine, aryl, alkyl, acyl, benzoyl, alkylcarbamyl or cobalt octacarbonyl, Coa(CO)8; and/or tetracobalt dode arylcarbamyl, preferably hydrogen or alkyl. Specific ex carbonyl, Co4(CO)12. As defined herein "cobalt carbon 40 amples of alkyl substituents are methyl, ethyl, n-propyl, y1' will refer to any one or all of the specific cobalt n-butyl, n-pentyl, n-hexyl, n-hepty, n-octyl, n-decyl, n carbonyls referred to above. It is generally believed that dodecyl, n-tetradecyl, n-hexadecyl, isopropyl, 2-methyl the cobalt carbonyl is the active form of catalyst for the butyl, 2-ethylpentyl, 3-butylhexyl, 4-pentyldecyl, 2,2'-di hydroformylation reaction. methyldecyl, 3-methyl-4-ethyldecyl, 5-propylhexyl, 3 Since cobalt carbonyls are thermally unstable and will 45 methyldodecyl, 6-ethyldodecyl, 3,3'-dimethyltetradecyl, 2 easily decompose to elemental cobalt and carbon mon butylhexadecyl, etc., and of aryl substituents are phenyl, oxide, it is necessary to maintain a high pressure of hy tolyl, Xylyl, 1,3,5-trimethylphenyl, ethylphenyl, propyl drogen and carbon monoxide in the hydroformylation re phenyl, butylphenyl, hexylphenyl, decylphenyl, dodecyl action zone to inhibit such decomposition at the elevated phenyl, tetradecylphenyl, hexadecylphenyl, etc. Specific ex temperatures existing in the hydroformylation reaction 50 amples of such compounds that can be employed herein zone. At the end of the reaction period, the reaction prod include: uct will consist largely of an aldehyde having one carbon more than the olefinic charge, plus unreacted hydrogen 2,4,6-tris(isopropyl)-1,3-dioxa-5-phosphacyclohexane, and carbon monoxide and some alcohol, corresponding to 2,4,6-tris(3-pentyl)-1,3-dioxa-5-phosphacyclohexane, the aldehyde, carrying dissolved cobalt carbonyl. The un 2,4,6-tris(3-heptyl)-1,3-dioxa-5-phosphacyclohexane, reacted hydrogen and carbon monoxide can rather easily 2,4,6-tris(3-decyl)-1,3-dioxa-5-phosphacyclohexane, be separated from the reaction product, for example, by 2,4,6-tris(3-tetradecyl)-1,3-dioxa-5-phosphacyclohexane, flash distillation, but the cobalt carbonyl is removed only 2,4,6-tris(3-hexadecyl)-1,3-dioxa-5-phosphacyclohexane, with difficulty. It is obvious that if the aldehyde product, 2,4,6-tris(butyl)-1,3-dioxa-5-phosphacyclohexane, as such, is desired, it would be necessary to remove co 60 2,4,6-tris(heptyl)-1,3-dioxa-5-phosphacyclohexane, balt carbonyl therefrom. In most cases the aldehyde is 2,4,6-tris(decyl)-1,3-dioxa-5-phosphacyclohexane, Subjected to hydrogenation conditions in the presence of 2,4,6-tris(tetradecyl)-1,3-dioxa-5-phosphacyclohexane, a hydrogenation catalyst, such as nickel, to convert the 2,4,6-tris(hexadecyl)-1,3-dioxa-5-phosphacyclohexane, aldehyde to the corresponding alcohol. In such case it 2,4,6-tris(2-butyl)-1,3-dioxa-5-phosphacyclohexane, becomes even more imperative to remove cobalt carbonyl 65 2,4,6-tris(2-hexyl)-1,3-dioxa-5-phosphacyclohexane, from the aldehyde being hydrogenated, since at the lower 2,4,6-tris(2-decyl)-1,3-dioxa-5-phosphacyclohexane, pressures employed in the hydrogenation reactor cobalt 2,4,6-tris(2-hexadecyl)-1,3-dioxa-5-phosphacyclohexane, carbonyl will decompose to cobalt and carbon monoxide, 2,4,6-tris(4-octyl)-1,3-dioxa-5-phosphacyclohexane, the latter being undesirable in the hydrogenation reaction 2,4,6-tris(4-dodecyl)-1,3-dioxa-5-phosphacyclohexane, Zone, since it has a tendency to poison the hydrogenation 70 2,4,6-tris(8-hexadecyl)-1,3-dioxa-5-phosphacyclohexane, catalyst, such as nickel, which is generally used. 2,4,6-tris(isopropyl)-1,3-dioxa-5-chloro-5-phosphacyclo It has been customary, therefore, to subject the hydro hexane, 3,644,529 3 w 4 2,4,6-tris(3-heptyl)-1,3-dioxa-5-fluoro-5-phosphacyclo butylamine, tri-n-hexylamine, tri-n-dodecylamine, tri-n- hexane, . - - - - - - hexadecylamine, tribenzylamine, N,N- dimethylbenzyl 2,4,6-tris (3-decyl)-1,3-dioxa-5-bromo-5-phosphacyclo amine, N,N-dimethylnaphthylamine, N,N-methylbutyl hexane, benzylamine, N,N-butylethylbenzylamine, N,N-diethyl 2,4,6-tris(2-butyl)-1,3-dioxa-5-iodo-5-phosphacyclo dodecylamine, 2,2,2'-iminotriethanol, 2,2,2'-iminotri hexane, ethylchloride, 4,4',4' - iminotributylchloride, 1,1,1'- 2,4,6-tris(isopropyl)-1,3-dioxa-5-acetyl-5-phosphacyclo iminotrimethylfluoride, 4,4',4' - iminotributyraldehyde, hexane, 7,7,7'-iminotriheptaldehyde, etc. 2,4,6-tris(isopropyl)-1,3-dioxa-5-benzoyl-5-phosphacyclo The cobalt complex defined above, that is, the complex hexane, O formed between cobalt carbonyl and the DPC is easily 2,4,6-tris(isopropyl)-1,3-dioxa-5-octyl-5-phosphacyclo obtained and employed herein. In a preferred embodiment hexane, it is obtained in situ in the hydroformylation reaction 2,4,6-tris(isopropyl)-1,3-dioxa-5-phenyl-5-phosphacyclo zone. Thus, one of the cobalt salts, for example, one of hexane, those defined above is introduced into the hydroformyla 2,4,6-tris(isopropyl)-1,3-dioxa-5-(p-chlorophenylcar tion reaction zone along with one of the defined DPC's, bamyl)-5-phosphacyclohexane, the olefin to be subjected to hydroformylation reaction, 2,4,6-tris(isopropyl)-1,3-dioxa-5-ethylcarbamyl-5- hydrogen and carbon monoxide. Any olefinic compound phosphacyclohexane, that can be subjected to hydroformylation reaction and etc. For purposes of simplicity herein, we shall refer can be converted therein to aldehyde having one more throughout the specification, except in the specified ex 20 carbon than said olefin can be employed. Representative amples, to these compounds as DPC. In the specific ex examples of olefins that can be employed include propyl amples DPC will refer to the specific compound 2,4,6-tri ene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, isopropyl-phospha-3,5-dioxacyclohexane. We believe that decene-1, tetradecene-1, hexadecene-1, pentene-2, hexene under the hydroformylation reaction conditions, the DPC, 2, heptene - 2, octene-2, 4-methyl-1-pentene, 2,4,4-tri as a ligand, combines with the cobalt carbonyl and forms methyl - 1-pentene, 4-methyl-2-pentene, 2,6-dimethyl-3- a complex therewith. By “ligand' we intend to include heptene, cyclopentene, cyclohexene, cycloheptene, cyclo DPC's which contain an element with an electron pair octene, 4-methyl-1-cyclohexene, etc. The molar ratio of that can form a coordination compound with a metal com hydrogen to carbon monoxide can be from about 5:1 to pound.