Patent GB-860645-A (GB)
Title: Process for preparing metal carbonyls
IPC: C07F9/28
Filed: 1957-10-01
Abstract: Organo-transition metal complexes of the type: <FORM:0860645/IV (b)/1> or <FORM:0860645/IV (b)/2> where M = a transition metal of Group IV-VIIb and VIII of the Periodic Table; A1=O or S; A2=N or P; R1 and R2 are organic groups characterized by the absence of (1) olefinic unsaturation, (2) hydrogen atoms on the carbon atom in the a -position to the carbon atom to which the O, S, N or P is bonded; R3=an organic radical and x and y are small whole numbers dependent upon the valence of M, x being 1, 2 or 3, y being 1 or 2, are prepared by reaction of a transition metal salt with an organo metallic intermediate of the type formed by reaction of a non-transition metal with organic compounds of the type <FORM:0860645/IV (b)/3> or <FORM:0860645/IV (b)/4> where R1, R2, R3 and A1 and A2 have the meaning above defined.  The radical R3 above may be an alkyl, aryl, alkenyl, alkaryl or aralkyl radical containing 1-16 carbon atoms.  Transition Transition metal salts employed are generally ionic compounds, e.g. halides, nitrates, sulphates, oxalates or acetates and the non-transition metal may be an alkali or alkaline earth metal or aluminium.  The organo metallic intermediate is preferably formed by reaction carried out in an inert atmosphere and by addition of the non-transition metal as a dispersion in mineral oil.  The organo metallic intermediate thus formed may then be reacted directly with the transition metal salt.  Alternatively, the organo metallic complex may be formed in one reaction by reacting the appropriate organic compound having a formula as specified above with a non-transition metal in the presence of a non-transition metal salt.  The reactions may be carried out in an inert solvent, e.g. benzene, toluene or hexane or preferably in non-reactive cyclic ethers, e.g. dioxane or tetrahydrofurane.  Of the organic compounds referred to above which may be ketones, thiones, imines or phosphine compounds, ketones and thiones containing 9-25 carbon atoms/molecule, e.g. 2,2,4,4 - tetramethyl 1-3-pentanethione; bis-(tert.-butyl) thione; bis-phenylthione; bis-(4-nitrohexyl) thione; bis-(1,1,3,3,4,4-hexamethyl pentyl) ketone; bis-(p-biphenyl) ketone; 1-phenyl 1-2, 5-diethyl 1-2, 4-dimethyl-1-hexathione; bis-(p-dimethyl amino phenyl) ketone; di-tert.-butyl ketone; diphenyl ketone; bis-(p - nitro - phenyl) thione, phenyl - tert. - butyl ketone; bis-(m-nitrophenyl) ketone; bis-(1-ethyl-1,3-dimethyl butyl) ketone, and imines and phosphine compounds containing 9-25 carbon atoms/molecule, e.g. p,p1-diaminobenzohydrylidene methyl imine; p,p1-diphenyl benzohydrylidine-n hexyl phosphine; m,m1-dinitro benzhoydrylidene benzyl phosphine; 4,4,6,6-tetramethyl - 5 - nonylidene ethyl imine; N - benzohydrylidene phenylimine; 2,2,4,4-tetramethyl - 3 - pentylidene methylimine; p-methyl benzohydrylidene benzylimine, benzohydrylidine - n - hexylimine and 2,4-diethyl-2,4-dimethyl-3-pentylidene-p-nitrophenylimine are specified.  Use of such organo metallic complexes to prepare transition metal carbonyls by reaction with CO (see Group III) is specified.ALSO:Transition metal carbonyls are prepared by reaction of CO with organo-transition metal complexes of the type: <FORM:0860645/III/1> or <FORM:0860645/III/2> where M = a transition metal of the Group IVb, Vb, VIb, VIIb and VIII of the Periodic Table; A1 = O or S; A2 = N or P; R1 and R2 are organic groups characterized by the absence of (1) olefinic unsaturation, (2) hydrogen atoms on the carbon atom in the a  position to the carbon atom to which the O, S, N or P is bonded; R3=an organic radical and x and y are whole numbers dependent upon the valence of M, and being 1, 2 or 3, y being 1 or 2.  R3 may be an ethyl, aryl, alkenyl, alkaryl or aralkyl radical containing 1-16 carbon atoms, organic hydrocarbon radicals being preferred.  Complexes of the type where A1=O and A2=N are preferred especially the complex formed by reaction of a transition metal salt and bis-(N-sodio-benzo phenoneimine).  In operation, a pressure vessel containing the required complex is pressurized at ambient temperature with Co to 250-50,000 p.s.i.g., preferably 500-3000 p.s.i.g., and is slowly heated to a reaction temperature of 50-300 DEG  C., preferably 150-230 DEG  C., for a time of 1/2 -2\ba1/2 hours or until the system no longer absorbs Co.  The reaction may be carried out in an inert solvent, e.g. benzene, toluene or hexane or preferably polar, non-reactive cyclic ethers, e.g. dioxane or tetrahydrofurane.  The metal carbonyl is recovered from the reaction products by hydrolysis and steam distillation followed by extraction of the aqueous distillate with a solvent, e.g. benzene, toluene or cyclohexane and finally purified by crystallization.  The organo metallic complexes (I) and (II) above may be prepared (see Group IV (b)) by reaction of a transition metal salt, e.g. halides, nitrates, sulphates, oxalates or acetates, with an organo metallic intermediate formed by the reaction of stoichiometric amounts of a non-transition metal, e.g. alkali metals, alkaline earth metals and aluminium, and organic compounds of the type <FORM:0860645/III/3> i.e. a ketone (A1=O) or a thione (A1=S) or <FORM:0860645/III/4> i.e. an imine (A2=N) or a phosphine compound (A2=P). The use of an imine, especially N-benzohydrylidenephenylimine, is preferred.  The Specification contains numerous examples of the various ketones, thiones, imines and phosphine compounds which may be employed.